Ge Secogear User guide

DET-882 Application and Technical Guide

SecoGear

$ZE $ZE8444MecP[-R[PS Switchgear

GE Energy Connections

Industrial Solutions

HAZARD CLASSIFICATIONS

The following important highlighted information appears

throughout this document to warn of potential hazards or

to call attention to information that clarifies a procedure.

Carefully read all instructions and become familiar with the

devices before trying to install, operate, service or maintain

this equipment.

DANGER

Indicates a hazardous situation that, if not avoided, will

result in death or serious injury.

WARNING

Indicates a hazardous situation that, if not avoided, could

result in death or serious injury.

CAUTION

Indicates that if the hazard is not avoidedcould result in

minor or moderate injury.

NOTICE

Is used to notify of practices not related to personal injury.

TRADEMARKS

SecoGear® Seco RMU®

Seco Cube® SecoBloc®

SecoVac® VB2+ Multilin®

All third party trademarks are the property of their

respective owners.

WARRANTY

This document is based on information available at the

time of its publication. While efforts have been made to

ensure accuracy, the information contained herein does

not cover all details or variations in hardware and software,

nor does it provide for every possible contingency in

connection with installation, operation, and maintenance.

Features may be described herein that are not present in

all hardware and software systems.

GE Industrial Solutions assumes no obligation of notice to

holders of this document with respect to changes

subsequently made. GE Industrial Solutions makes no

representation or warranty, expressed, implied, or

statutory, with respect to, and assumes no responsibility

for the accuracy, completeness, sufficiency, or usefulness

of the information contained herein.

No warrantees of merchantability or fitness for purpose

shall apply.

Contact your local sales office if further information is

required concerning any aspect of SecoGear switchgear

and SecoVac VB2+ breaker operation or maintenance.

SecoGear Medium-voltage Switchgear Application and Technical Guide DET-882

TABLE OF CONTENTS

SECTION 1. SecoGear Switchgear Concepts and Basic Configurations......................................................................................1

SecoGear Metal-clad Switchgear...............................................................................................................................................................................................1

Switchgear Standards......................................................................................................................................................................................................................3

Underwriters Laboratories, Inc. (UL)....................................................................................................................................................................................3

Service Conditions........................................................................................................................................................................................................................3

Temperature................................................................................................................................................................................................................................3

Humidity........................................................................................................................................................................................................................................3

Altitude...........................................................................................................................................................................................................................................3

Applicable Industry Standards...............................................................................................................................................................................................3

Modular Construction and Typical Sectional Views.........................................................................................................................................................3

Modular Compartments............................................................................................................................................................................................................3

Rollout Configurations................................................................................................................................................................................................................5

Two-High Breaker and Auxiliary Stacking.......................................................................................................................................................................6

SECTION 2. Circuit Breaker Selection.............................................................................................................................................. 10

Circuit Breaker Ratings..................................................................................................................................................................................................................10

Selection Considerations..............................................................................................................................................................................................................10

Circuit Voltage..............................................................................................................................................................................................................................10

System Frequency ....................................................................................................................................................................................................................10

Short-Circuit Current................................................................................................................................................................................................................10

Closing and Latching Current..............................................................................................................................................................................................11

Continuous Current...................................................................................................................................................................................................................11

Rated Interrupting Time..........................................................................................................................................................................................................11

Duty Cycle......................................................................................................................................................................................................................................11

Special Switching Applications.................................................................................................................................................................................................11

Automatic Transfer...................................................................................................................................................................................................................11

Capacitor Switching..................................................................................................................................................................................................................12

Usual Service Conditions........................................................................................................................................................................................................12

Unusual Service Conditions..................................................................................................................................................................................................12

Abnormal Temperature......................................................................................................................................................................................................12

Temperature Rise...................................................................................................................................................................................................................12

High Altitude.............................................................................................................................................................................................................................12

Breaker Accessories .......................................................................................................................................................................................................................13

Breaker Lift Truck.............................................................................................................................................................................................................................13

Related Circuit Breaker References........................................................................................................................................................................................14

Typical Breaker Device Internals.............................................................................................................................................................................................16

SECTION 3. Control Power Equipment............................................................................................................................................ 18

Control Power Requirements.....................................................................................................................................................................................................18

Breaker Close and Trip Considerations..........................................................................................................................................................................18

Breaker Tripping .........................................................................................................................................................................................................................18

DC Battery Trip........................................................................................................................................................................................................................19

SecoVac Autocharge Capacitor Trip Device............................................................................................................................................................19

Direct Acting Undervoltage Trip Device.....................................................................................................................................................................19

Breaker Closing...........................................................................................................................................................................................................................19

Indicating Lamps........................................................................................................................................................................................................................20

Relaying................................................................................................................................................................................................................................................20

Excitation Power...............................................................................................................................................................................................................................20

Other Loads.........................................................................................................................................................................................................................................20

Control Power Source Selection...............................................................................................................................................................................................21

DC Control Power Equipment..............................................................................................................................................................................................21

Battery Systems.........................................................................................................................................................................................................................21

Lead-Acid Batteries..............................................................................................................................................................................................................21

Nickel-Cadmium Batteries................................................................................................................................................................................................21

DET-882 SecoGear Medium-voltage Switchgear Application and Technical Guide

Battery Capacity and Sizing.................................................................................................................................................................................................21

Battery Chargers.........................................................................................................................................................................................................................22

AC Control Power Equipment.....................................................................................................................................................................................................23

Application......................................................................................................................................................................................................................................23

Selection..........................................................................................................................................................................................................................................23

Guide to Estimating Heat Loss...................................................................................................................................................................................................24

SECTION 4. System and Equipment Protection.............................................................................................................................25

Basic System Protection...............................................................................................................................................................................................................28

Phase Overcurrent Protection..............................................................................................................................................................................................28

Incoming Lines.........................................................................................................................................................................................................................28

Feeders........................................................................................................................................................................................................................................28

Feeder Ties.................................................................................................................................................................................................................................28

Bus Ties........................................................................................................................................................................................................................................28

Transformers............................................................................................................................................................................................................................28

Generators.................................................................................................................................................................................................................................28

Ground Overcurrent Protection..........................................................................................................................................................................................29

Transformers and Generators.........................................................................................................................................................................................30

Directional Phase Overcurrent Protection.....................................................................................................................................................................30

Directional Ground Overcurrent Protection..................................................................................................................................................................30

High Impedance Ground Fault Detection......................................................................................................................................................................30

Differential Protection..............................................................................................................................................................................................................30

Bus Protection..........................................................................................................................................................................................................................31

Transformer Protection.......................................................................................................................................................................................................31

Motors...........................................................................................................................................................................................................................................31

Transmission Line...................................................................................................................................................................................................................31

Open Phase Protection............................................................................................................................................................................................................31

Automatic Reclosing.................................................................................................................................................................................................................31

Directional Power, Underfrequency, and Undervoltage Protection................................................................................................................32

Arc Flash Detection..........................................................................................................................................................................................................................32

Basic Equipment Protection........................................................................................................................................................................................................32

Circuit Breaker Control and Control Power Protection...........................................................................................................................................32

Instrumentation, Current, and Voltage Transformers.............................................................................................................................................33

AM and VM Scales..................................................................................................................................................................................................................33

CT and VT Ratios.....................................................................................................................................................................................................................33

Metering and Test Block..........................................................................................................................................................................................................34

Control and Transfer Switches........................................................................................................................................................................................34

Surge Protection..........................................................................................................................................................................................................................34

ANSI Device Functions and Acronyms..................................................................................................................................................................................34

SECTION 5. SecoGear Switchgear Applications.............................................................................................................................37

Glossary: Basic Equipment Applications..............................................................................................................................................................................37

General-Purpose Feeders (GPF)................................................................................................................................................................................................38

Protective Scheme Selection................................................................................................................................................................................................38

Optional Equipment Selection..............................................................................................................................................................................................38

Protection...................................................................................................................................................................................................................................38

Current Transformers for Differential Circuits.........................................................................................................................................................38

Indication....................................................................................................................................................................................................................................38

Control..........................................................................................................................................................................................................................................39

Transformer Primary Feeders (TPF).........................................................................................................................................................................................40

Single-Source Incoming Lines (SSIL), or Dual Source with Normally Open Tie Breakers............................................................................40

SecoGear Medium-voltage Switchgear Application and Technical Guide DET-882

Dual-Source Incoming Lines (DSIL).........................................................................................................................................................................................43

Basic Equipment Selection....................................................................................................................................................................................................43

Location of Optional Devices...........................................................................................................................................................................................43

Bus Ties (BT).........................................................................................................................................................................................................................................44

Bus Entrances (BE)...........................................................................................................................................................................................................................46

Optional Indication Selection...............................................................................................................................................................................................46

Induction Motor Feeders (IMF)...................................................................................................................................................................................................46

Optional Equipment Selection (for IMFE, IMF1, IMF2)..............................................................................................................................................47

Reduced Voltage Starting............................................................................................................................................................................................................49

Synchronous Motor Feeders (SMF).........................................................................................................................................................................................49

Optional Equipment Selection (for SMF1 and SMF2)...............................................................................................................................................50

Excitation....................................................................................................................................................................................................................................50

Standard Breaker and Auxiliary Configurations..............................................................................................................................................................52

Standard Tie Breaker and Auxiliary Configurations......................................................................................................................................................53

SECTION 6. Standard SecoGear Construction, Features, and Installation.............................................................................. 55

Documentation.................................................................................................................................................................................................................................55

Construction.......................................................................................................................................................................................................................................55

Indoor Equipment......................................................................................................................................................................................................................55

Hardware........................................................................................................................................................................................................................................55

Breaker Compartments..........................................................................................................................................................................................................55

Visual Breaker Position Indication................................................................................................................................................................................56

Auxiliary Compartments........................................................................................................................................................................................................56

Compartment Doors............................................................................................................................................................................................................56

Safety Interlocks.........................................................................................................................................................................................................................57

Secondary Disconnect Interlocking.............................................................................................................................................................................57

Safety Key Lock Provisions...............................................................................................................................................................................................58

Padlock for Open/Close Pushbutton (Optional).....................................................................................................................................................59

Main Bus.........................................................................................................................................................................................................................................59

Secondary Control.....................................................................................................................................................................................................................59

Door-mounted Devices......................................................................................................................................................................................................59

Equipment-mounted Devices.........................................................................................................................................................................................59

DET-882 SecoGear Medium-voltage Switchgear Application and Technical Guide

Wiring............................................................................................................................................................................................................................................60

Power Termination Compartment.....................................................................................................................................................................................60

Ground Bus....................................................................................................................................................................................................................................61

Equipment Heaters....................................................................................................................................................................................................................61

Finish and Paint...........................................................................................................................................................................................................................61

Unit Nameplates.........................................................................................................................................................................................................................61

Accessories....................................................................................................................................................................................................................................61

Breaker Test Box.....................................................................................................................................................................................................................61

Breaker Racking Mechanism...........................................................................................................................................................................................61

Ground and Test Device.....................................................................................................................................................................................................61

Identification of Breakers and Equipment.....................................................................................................................................................................62

Installation Information.................................................................................................................................................................................................................63

Shipping Splits..............................................................................................................................................................................................................................63

Indoor Foundation Preparation...........................................................................................................................................................................................63

Anchoring Details........................................................................................................................................................................................................................64

Embedded Floor Channel Requirements...................................................................................................................................................................64

SECTION 7. Ground and Test Device ...............................................................................................................................................66

Safety......................................................................................................................................................................................................................................................66

TABLE OF FIGURES

Figure 1-1: Typical SecoGear 2-High Section............................................................................................................................................................................1

Figure 1-2: Section Contents...............................................................................................................................................................................................................2

Figure 1-3: Typical One-High Breaker............................................................................................................................................................................................2

Figure 1-4: Typical Two-High Breakers.........................................................................................................................................................................................3

Figure 1-5: Dual VT Rollouts, Line/Bus Connected – Upper or Lower Section..........................................................................................................4

Figure 1-6: Dual CPT Rollouts, Line/Bus Connected – Upper or Lower Section.......................................................................................................4

Figure 1-7: 1200 A/2000 A – Upper or Lower Breaker Section.........................................................................................................................................4

Figure 1-8: VT Rollout, Line/Bus Connected and Fuse Rollout, Line Connected – Lower Section..................................................................4

Figure 1-9: Dual Rollouts.......................................................................................................................................................................................................................5

Figure 1-10: Single Rollouts.................................................................................................................................................................................................................5

Figure 1-11: Breaker in Compartment A, Bus-connected VTs in Compartment B.................................................................................................6

Figure 1-12: Breaker in Compartment A, Line-connected VTs in Compartment B................................................................................................6

Figure 1-13: Breaker in Compartment A, Bus-connected VTs and CPT Fuse Rollout in Compartment B..................................................6

Figure 1-14: Breaker in Compartment A, Line-connected CPT and VT Rollouts in Compartment B.............................................................6

Figure 1-15: Breaker in Compartment A, Line- and Bus-connected VT Rollouts in Compartment B...........................................................7

Figure 1-16: Breaker in Compartment B, Bus-connected VT Rollout in Compartment A...................................................................................7

Figure 1-17: Breaker in Compartment B, Bus-connected CPT in Compartment A.................................................................................................7

Figure 1-18: Bus Entry in Compartment A – Cabling Above, Breaker in Compartment B – Cabling Below..............................................7

Figure 1-19: Breaker in Compartment B, Bus-connected VTs and CPT in Compartment A..............................................................................8

Figure 1-20: Breaker in Compartment B, Line-connected VT Rollouts in Compartment A................................................................................8

Figure 1-21: Typical Two-high Breaker Section – Cabling Below....................................................................................................................................8

Figure 1-22: Typical Two-high Breaker Section – Cabling Above...................................................................................................................................8

Figure 1-23: Breaker in Compartment A – Cabling Above, Bus Entry in Compartment B – Cabling Below..............................................9

Figure 1-24: Breaker in Compartment A, Bus-connected VTs and Line-connected Fuse Rollout in Compartment B........................9

Figure 1-25: Bus-connected VTs in Compartment A, Bus Tie Breaker in Compartment B................................................................................9

Figure 1-26: Bus-connected VTs in Compartment A, Aux Tie in Compartment B..................................................................................................9

Figure 2-1: SecoVac VB2+ Circuit Breaker................................................................................................................................................................................10

Figure 2-2: Lift Truck.............................................................................................................................................................................................................................14

Figure 2-3: SecoVac VB2+ Breaker Front Panel.....................................................................................................................................................................15

Figure 2-4: Spring Discharge Instructions................................................................................................................................................................................15

Figure 2-5: System Wiring Diagram.............................................................................................................................................................................................16

Figure 2-6: Terminal Block Located in Switchgear...............................................................................................................................................................16

Figure 2-7: Secondary Disconnect...............................................................................................................................................................................................16

Figure 2-8: Example – Main Breaker Control Circuit, 850 Relay, Expanded MOC Switch................................................................................17

Figure 4-1: Multilin Website Features – Motor Protection Selection...........................................................................................................................26

SecoGear Medium-voltage Switchgear Application and Technical Guide DET-882

Figure 4-2: Multilin Website Features – Digital Metering Selection............................................................................................................................27

Figure 5-1: General-Purpose Feeder...........................................................................................................................................................................................39

Figure 5-2: Transformer Primary Feeder..................................................................................................................................................................................40

Figure 5-3: Single-source Incoming Line..................................................................................................................................................................................42

Figure 5-4: Dual-Source Incoming Line.....................................................................................................................................................................................44

Figure 5-5: Bus Tie.................................................................................................................................................................................................................................45

Figure 5-6: Bus Entrance...................................................................................................................................................................................................................46

Figure 5-7: Induction Motor Feeder.............................................................................................................................................................................................48

Figure 5-8: Reduced Voltage Reactor Start.............................................................................................................................................................................49

Figure 5-9: Synchronous Motor Feeder.....................................................................................................................................................................................51

Figure 5-10: Sample Lineup – A.....................................................................................................................................................................................................52

Figure 5-11: Sample Lineup – B.....................................................................................................................................................................................................52

Figure 5-12: Tie Breaker and Aux Tie Stack.............................................................................................................................................................................53

Figure 5-13: Bus VTs on Each Side of Tie Breaker................................................................................................................................................................53

Figure 5-14: Feeder Breakers in Upper Compartment......................................................................................................................................................53

Figure 5-15: Bus VT in the Aux Tie Compartment................................................................................................................................................................53

Figure 5-16: Typical Main-Tie-Main Example with Eight Feeder Breakers.............................................................................................................54

Figure 6-1: Breaker Compartment...............................................................................................................................................................................................55

Figure 6-2: Ground Shoe in Breaker Cell...................................................................................................................................................................................56

Figure 6-3: Breaker Position – Disconnected (Green).........................................................................................................................................................56

Figure 6-4: Breaker Position – Intermediate (Yellow)..........................................................................................................................................................56

Figure 6-5: Breaker Position – Connected (Red)....................................................................................................................................................................56

Figure 6-6: Door Stop and Hinges................................................................................................................................................................................................57

Figure 6-7: Optional IR Viewing Window...................................................................................................................................................................................57

Figure 6-8: Optional Lockable T Handle....................................................................................................................................................................................57

Figure 6-9: Disconnect Plug Not Mechanically Interlocked............................................................................................................................................58

Figure 6-10: Disconnect Plug Mechanically Interlocked..................................................................................................................................................58

Figure 6-11: Rear Door Padlocking Provision.........................................................................................................................................................................58

Figure 6-12: Front Door Padlocking Provision........................................................................................................................................................................58

Figure 6-13: Breaker Racking Padlock.......................................................................................................................................................................................58

Figure 6-14: Shutter Padlocking Provision...............................................................................................................................................................................59

Figure 6-15: Open/Close Pushbutton Locked.........................................................................................................................................................................59

Figure 6-16: Open/Close Pushbutton Open............................................................................................................................................................................59

Figure 6-17: CT Mounting in Breaker Compartment ..........................................................................................................................................................59

Figure 6-18: Typical Ring-Type CTs Mounted in SecoGear Breaker Cell..................................................................................................................60

Figure 6-19: Typical Indoor Voltage Transformer................................................................................................................................................................60

Figure 6-20: Rear View of Two high Compartment Showing Cable Trough..........................................................................................................60

Figure 6-21: Cable Trough Opening.............................................................................................................................................................................................61

Figure 6-22: Ground Bus Bar Bolt Locations...........................................................................................................................................................................61

Figure 6-23: SecoVac Test Box.......................................................................................................................................................................................................61

Figure 6-24: Breaker Racking Mechanism...............................................................................................................................................................................61

Figure 6-25: Ground and Test Device.........................................................................................................................................................................................62

Figure 6-26: SecoVac Barcode.......................................................................................................................................................................................................62

Figure 6-27: SecoVac Nameplate.................................................................................................................................................................................................62

Figure 6-28: SecoGear Label...........................................................................................................................................................................................................62

Figure 6-29: Section Cutaway (Height, Width, and Depth)..............................................................................................................................................64

Figure 6-30: SecoGear Installation Drawing – Indoor Anchoring Method..............................................................................................................64

Figure 6-31: SecoGear Primary Indoor Anchoring Method............................................................................................................................................65

Figure 6-32: SecoGear Alternate Indoor Anchoring Method..........................................................................................................................................65

Figure 6-33: Installation Top View................................................................................................................................................................................................65

Figure 7-1: Device, Front View........................................................................................................................................................................................................66

Figure 7-2: Device, Contact Arms.................................................................................................................................................................................................66

TABLE OF TABLES

Table 1-1: Typical Dimensions for Indoor Construction......................................................................................................................................................2

Table 1-2: Applicable American National Standards Institute (ANSI) Standards....................................................................................................3

DET-882 SecoGear Medium-voltage Switchgear Application and Technical Guide

Table 1-3: Applicable National Electrical Manufacturers Association (NEMA) Standards..................................................................................3

Table 1-4: Permitted Rollout Unit Combinations......................................................................................................................................................................5

Table 2-1: SecoVac VB2+ Vacuum Circuit Breaker Characteristics............................................................................................................................11

Table 2-2: SecoVac Breaker Capacitor Switching Capabilities......................................................................................................................................12

Table 2-3: Altitude Correction Factors* for SecoVac VB2+ Circuit Breakers and SecoGear Switchgear................................................13

Table 3-1: SecoVac VB2+ IEEE Circuit Breaker Control Voltages and Currents....................................................................................................18

Table 3-2: Contact Ratings for MOC, TOC, and Breaker Auxiliary Switches............................................................................................................18

Table 3-3: Simultaneous Breaker Tripping ...............................................................................................................................................................................20

Table 3-4: GE Type HEA Lockout Relay Coil Current Characteristics.........................................................................................................................20

Table 3-5: AC Load Factor for Charger Battery Voltage...................................................................................................................................................20

Table 3-6: Battery Selection Guide...............................................................................................................................................................................................21

Table 3-7: Battery Sizing, Example A...........................................................................................................................................................................................22

Table 3-8: Battery Sizing, Example B...........................................................................................................................................................................................22

Table 3-9: AC Load Estimating Example....................................................................................................................................................................................23

Table 3-10: Heat Loss per Breaker................................................................................................................................................................................................24

Table 3-11: Heat Loss per Section................................................................................................................................................................................................24

Table 4-1: Remote Control Schemes...........................................................................................................................................................................................33

Table 4-2: Single Ratio CTs................................................................................................................................................................................................................33

Table 4-3: Multiple Ratio CTs............................................................................................................................................................................................................34

Table 4-4: ANSI Device Codes..........................................................................................................................................................................................................34

Table 6-1: SecoGear Characteristics...........................................................................................................................................................................................63

Table 7-1: SecoVac VB2+ Vacuum Circuit Breaker Characteristics............................................................................................................................66

DET-882 SecoGear Medium-voltage Switchgear Application and Technical Guide

SecoGear Switchgear Concepts and Basic Configurations

SECTION 1. SECOGEAR SWITCHGEAR CONCEPTS AND BASIC CONFIGURATIONS

This Application Guide provides information necessary to

help plan and specify medium-voltage power system

switchgear by utilizing SecoGear Metal-clad switchgear.

This publication can be used to write complete

specifications for most switchgear applications. Included is

guidance in equipment layout, ratings, relay protection,

and references to appropriate standards and literature.

General Electric engineering services, under special

contract agreements, will perform power systemstudies,

including the necessary calculations and comparisons.

The first four sections of this guide discuss topics

applicable to any type of medium-voltage metal-clad

switchgear. Information is provided for circuit breaker

ratings and selection, control power requirements, basic

circuit protections considerations, and specific

recommendations for protection, instrumentation, and

control for basic switchgear circuits.

The remaining sections of the application guide explain

SecoGear application and specification. The modular

construction and the use of multifunction relays and

meters are basic to SecoGear and are shown through

application details covering the use of SecoGear

switchgear and SecoVac breakers in basic circuit

applications. Also included are auxiliary unit and power

conductor compartment structuring.

After selecting individual units, an optimum lineup

configuration can be developed using the guidelines given.

A specification procedure, complete with Guide Form

Specifications, is recommended to facilitate the

documentation of SecoGear Metal-clad switchgear

requirements.

Start with your system voltage and current requirements,

and work through the guide in a step-by-step fashion. The

guide’s structure is based on extensive engineering

experience and will serve as a checklist to aid in preparing

complete specifications.

A brief introduction to SecoGear will serve as a useful

starting point to begin the application procedure.

SECOGEAR METAL-CLAD SWITCHGEAR

SecoGear Metal-clad switchgear is designed to house the

latest GE vacuum circuit breaker, SecoVac VB2+, and can

be used for applications on 4.76 kV, 8.25 kV, and 15 kV

power systems for 31.5 kA and 40 kA. A typical section of

SecoGear with a single breaker and rollout compartment is

shown in Figure 1-1.

Figure 1-1: Typical SecoGear 2-High Section

SecoGear metal-clad switchgear is designed with a full IEEE

metal-clad compartment, bus, and cabling isolation.

SecoVac breakers offer the benefits of reliable vacuum

interrupters, low maintenance, and reduced breaker size

and weight.

Specifically, SecoGear switchgear incorporates the

following basic design elements:

•SecoGear provides two-high breaker stacking for

application flexibility and floor space savings

SecoGear Medium-voltage Switchgear Application and Technical Guide DET-882

SecoGear Switchgear Concepts and Basic Configurations

•SecoGear utilizes modular construction resulting in one

basic vertical section size, simplifying system planning

and increasing installation savings

•SecoGear features four-high auxiliary arrangements,

providing additional flexibility and use of floor space

•SecoGear allows for intermixing auxiliary and a breaker

compartment in the same vertical section

Certain elements in the switchgear application procedure

are affected by these fundamental design features. Cubicle

stacking, cabling direction, and VT & CPT compartment

considerations are key when translating the one-line

diagram into a valid arrangement of switchgear cubicles,

auxiliary rollouts, and bus connections in a lineup. These

application considerations are necessary as a result of the

equipment design. A brief illustration of SecoGear

switchgear design concepts is provided to assist in

understanding.

Figure 1-2: Section Contents

Table 1-1: Typical Dimensions for Indoor Construction

Height (h)

95 in [2413 mm]

Width (w)

36 in [914 mm]

Depth (d)

95.05 in [2414 mm]

Breakers and auxiliary devices can be accommodated in

the upper and lower compartments, as shown in Figure 1-3

and Figure 1-4, in a variety of configurations.

Figure 1-3: Typical One-High Breaker

A = Main Busbar

Compartment

B = Circuit Breaker

Compartment

C = Cable

Compartment

D = Front Doors

DET-882 SecoGear Medium-voltage Switchgear Application and Technical Guide

SecoGear Switchgear Concepts and Basic Configurations

Figure 1-4: Typical Two-High Breakers

SWITCHGEAR STANDARDS

SecoVac VB2+ circuit breakers are rated per IEEE C37.04

and C37.06 standards (Table 1-2). Available ratings are

shown in Table 3-1.

SecoGear switchgear is designed, built, and tested to the

applicable industry standards shown in Table 1-2 and

Table 1-3.

SecoGear equipment is available in NEMA 1 indoor

construction. Typical section outlines for each of the basic

equipment types,along with dimensions and weights are

shown in SECTION 6. “Standard SecoGear Construction,

Features, and Installation.”

Underwriters Laboratories, Inc. (UL)

SecoGear Metal-clad switchgear and associated circuit

breakers are available with the option for UL labeling (File

No. E468553). Device selection and options are all

considerations when providing a UL label. The requirement

for UL labeling must be made known during the bidding

stage and agreed to by GE.

NOTICE

Not all medium-voltage switchgear assemblies

qualify for UL listing.

Service Conditions

SecoGear is designed for the normal service conditions of

indoor switchgear per IEEE Standards:

Temperature

•Maximum Ambient: 104 °F [40 °C]

•Minimum Ambient: -22 °F [-30 °C]

Humidity

•Maximum Relative: 95%

Altitude

•Maximum: 3300 ft [1000 m] a.s.l.

•High Altitude: At altitudes above 1000 m, consult

IEEEC27.20.2 for derating factors applicable to

dielectric and current values

Applicable Industry Standards

Table 1-2: Applicable American National Standards

Institute (ANSI) Standards

Standard No.

Description

C37.04

Rating Structure for AC High-Voltage Circuit

Breaker IEEE Standard

C37.06

AC High-Voltage Circuit Breakers Rated on

a Symmetrical Current Basis - Preferred

Ratings and Related Required Capabilities

Breakers

C37.09

IEEE Standard Test Procedure for AC High-

Voltage Circuit Breakers Rated on a

symmetrical Current Basis Breakers

C37.10 Application Guide for Power Circuit

Breakers

C37.11 Power Circuit Breaker Electrical Control

Requirements

C37.20.2

Metal-Clad Switchgear Assemblies

Table 1-3: Applicable National Electrical Manufacturers

Association (NEMA) Standards

Standard No.

Description

SG-4

Power Circuit Breakers

SG-5

Power Switchgear Assemblies

Compliance with other national standards must be

reviewed with GE Sales.

MODULAR CONSTRUCTION AND TYPICAL SECTIONAL

VIEWS

The standard cubicles or modules are shown in Figure 1-5

through Figure 1-8. The basic concepts for two-high unit

stacking and options with rollouts are shown in Figure 1-9

and Figure 1-10. Additional illustrations will be provided to

assist in the layout of a SecoGear lineup in SECTION 5

“SecoGear Switchgear Applications.”

Modular Compartments

VT Rollout and CPT Rollouts can be intermixed in the same

compartment. The rollouts are the same physical size and

can be either upper or lower drawout tray.

SecoGear Medium-voltage Switchgear Application and Technical Guide DET-882

SecoGear Switchgear Concepts and Basic Configurations

Figure 1-5: Dual VT Rollouts, Line/Bus Connected –

Upper or Lower Section

Figure 1-6: Dual CPT Rollouts, Line/Bus Connected –

Upper or Lower Section

Figure 1-7: 1200 A/2000 A – Upper or Lower

Breaker Section

Figure 1-8: VT Rollout, Line/Bus Connected and Fuse

Rollout, Line Connected – Lower Section

CPT

Space for 4 CTs per phase:

•2 on upper studs

•

2 on lower studs

Breaker

Fuse Rollout

DET-882 SecoGear Medium-voltage Switchgear Application and Technical Guide

SecoGear Switchgear Concepts and Basic Configurations

Rollout Configurations

Figure 1-9: Dual Rollouts

Figure 1-10: Single Rollouts

Table 1-4: Permitted Rollout Unit Combinations

Device

Ratings

Compartment A,

Single Rollout

Compartment A,

Dual Rollouts

Compartment B,

Single Rollout

Compartment B,

Dual Rollouts

Upper

Lower

Upper

Lower

VT Rollout

5 kV – 15 kV

Yes

CPT Rollout

5 kVA, 10 kVA, 15 kVA

Yes

Fuse

Yes

Notes:

1. All fuse rollouts are equipped with fuse clips forsize C EJ1/EJO1 fuses. Clips can be adjusted for 12” or15” centers. Fuse rollouts requirethe installation

of a keylock to prevent pulling the drawer out under load.

2. A single rollout in compartment A or B can be located in the upper or lower position, as shown in Figure 1-10.

3. A fused rollout in compartment A is available as bus connected only.

4. The upper rollout in compartment A can be bus connected as long as the lower rollout in compartment A is bus connected. The lower rollout in

compartment A can be bus connected, regardless of the connection to the upper rollout in compartment A. The lower rollout in compartment A can be

line connected only if the upper rollout in compartment A is also line connected.

5. The lower rollout in compartment Bcan bebus connected as long as the upper rollout in compartment B is bus connected. The lower rollout in

compartment B can be line connected, regardless of the connection to the upper rollout in compartment B. The upper rollout in compartment B can

only be line connected if the lower rollout if compartment B is also line connected.

CPT

Fuse Rollout

Compartment A

Compartment B

Upper Rollout

Lower Rollout

Upper Rollout

Lower Rollout

Compartment A

Compartment B

SecoGear Medium-voltage Switchgear Application and Technical Guide DET-882

SecoGear Switchgear Concepts and Basic Configurations

Two-High Breaker and Auxiliary Stacking

SecoGear allows stacking of various modules or

compartments into a vertical section. Typical equipment

section views in Figure 1-11 through Figure 1-26 illustrate

how upper and lower units can be combined with the

associated power connections.

Figure 1-11: Breaker in Compartment A, Bus-connected

VTs in Compartment B

Figure 1-12: Breaker in Compartment A, Line-connected

VTs in Compartment B

Figure 1-13: Breaker in Compartment A, Bus-connected

VTs and CPT Fuse Rollout in Compartment B

* Cabling to the breaker must enter or exit above.

Figure 1-14: Breaker in Compartment A, Line-connected

CPT and VT Rollouts in Compartment B

Breaker

CTs

Breaker*

Fuse Rollout

CTs

Breaker

CTs

CPT

DET-882 SecoGear Medium-voltage Switchgear Application and Technical Guide

SecoGear Switchgear Concepts and Basic Configurations

Figure 1-15: Breaker in Compartment A, Line- and Bus-

connected VT Rollouts in Compartment B

Figure 1-16: Breaker in Compartment B, Bus-connected

VT Rollout in Compartment A

Figure 1-17: Breaker in Compartment B, Bus-connected

CPT in Compartment A

Figure 1-18: Bus Entry in Compartment A – Cabling

Above, Breaker in Compartment B – Cabling Below

Breaker

CTs

Breaker

CTs

Breaker

CTs

CPT

Breaker

CTs

SecoGear Medium-voltage Switchgear Application and Technical Guide DET-882

SecoGear Switchgear Concepts and Basic Configurations

Figure 1-19: Breaker in Compartment B, Bus-connected

VTs and CPT in Compartment A

Figure 1-20: Breaker in Compartment B, Line-connected

VT Rollouts in Compartment A

Figure 1-21: Typical Two-high Breaker Section –

Cabling Below

Figure 1-22: Typical Two-high Breaker Section –

Cabling Above

Breaker

CTs

CPT

Breaker

CTs

Breaker

CTs

Breaker

GSCT

Breaker

CTs

Breaker

GSCT

DET-882 SecoGear Medium-voltage Switchgear Application and Technical Guide

SecoGear Switchgear Concepts and Basic Configurations

Figure 1-23: Breaker in Compartment A – Cabling Above,

Bus Entry in Compartment B – Cabling Below

Figure 1-24: Breaker in Compartment A, Bus-connected

VTs and Line-connected Fuse Rollout in Compartment B

Figure 1-25: Bus-connected VTs in Compartment A, Bus

Tie Breaker in Compartment B

Figure 1-26: Bus-connected VTs in Compartment A, Aux

Tie in Compartment B

Breaker

CTs

Breaker*

Fuse Rollout

CTs

Breaker

CTs

SecoGear Medium-voltage Switchgear Application and Technical Guide DET-882

Circuit Breaker Selection

SECTION 2. CIRCUIT BREAKER SELECTION

ANSI-C37.100 defines a circuit breaker:

A mechanical switching device, capable of making,

carrying, and breaking currents under normal circuit

conditions and also, making, carrying for a specified time

and breaking currents under specified abnormal circuit

conditions such as those of short circuit.

Figure 2-1: SecoVac VB2+ Circuit Breaker

The function of a circuit breaker is to carry and switch load

current and to interrupt short-circuit current when

required. A circuit breaker can be used to operate

frequently or infrequently, depending on the type and

application. To properly select a circuit breaker, it is

important to consider that the rating of the circuit breaker

must equal or exceed each of the calculated duty

requirements of the circuit in which the breaker is applied.

CIRCUIT BREAKER RATINGS

GE SecoVac VB2+ circuit breaker ratings are shown in

Table 2-1. Interrupting ratings are intended for 60 Hz and

50 Hz applications. Table 1-2 and Table 1-3 show more

information on service conditions, definitions, ratings, test

and other applicable terms listed in ANSI and NEMA

standards.

SELECTION CONSIDERATIONS

Circuit breaker selection is based on the duty requirements.

For your application, find the model SecoVac VB2+ circuit

breaker rated for those specifications (Table 2-1). It is

important to consult the ANSI Standard C37.010 for proper

guidance on duty requirements (see “Related Circuit

Breaker References,” item 2).

When selecting a circuit breaker, you must consider

several characteristics such as circuit voltage, system

frequency, continuous current, short-circuit current and

closing and latching current.

Circuit Voltage

ANSI standards determine that the nominal voltage classes

for medium voltage metal-clad switchgear are 4.16 kV, 7.2

kV, and 13.8 kV; in accordance with ANSI, SecoGear

switchgear is designed to operate at a voltage range from

2,400 V through 15,000 V.

System Frequency

SecoGear Metal-clad switchgear is rated to 60 Hz as a

standard with the option to provide a 50 Hz solution as

required. When determining the system frequency of any

switchgear, remember that the frequency rating should be

the same as the nominal frequency of the power system.

Short-Circuit Current

One of the first things to consider when selecting a circuit

breaker is the interruption rating of short-circuit current, for

any SecoVac VB2+ circuit breaker, the interrupting rating is

stated in three-phase, symmetrical, rms AC amperes.

Start by calculating the short-circuit current duty, followed

by selecting the required voltage class, and finally

determine the short-circuit current capability of SecoVac

that equals or exceeds the expected duty.

DET-882 SecoGear Medium-voltage Switchgear Application and Technical Guide

Circuit Breaker Selection

Table 2-1: SecoVac VB2+ Vacuum Circuit Breaker Characteristics

Characteristic

1200/31.5 Rating

1200/40 Rating

2000/40 Rating

Rated current

1200 A

2000 A

Rated voltage (max.) 4.76 kV, 8.25 kV,

15 kV 4.76 kV, 8.25 kV,

15 kV

Nominal ANSI voltage class 4.16 kV, 7.2 kV,

13.8 kV 4.16 kV, 7.2 kV,

13.8 kV

Rated frequency 50 Hz, 60 Hz 50 Hz, 60 Hz 50 Hz, 60 Hz

Rated dielectric

withstand test voltage Power frequency rms voltage 36 kV 36 kV 36 kV

Crest impulse voltage

95 kV

Rated short-circuit current (max interrupting capability)

31.5 kA

40 kA

Rated interrupting time 3 cycles 3 cycles 3 cycles

Rated permissible tripping delay

2 s

Short time current carrying capability

31.5 kA

40 kA

Close and latch current peak (2.6 x short-circuit current rating)

82 kA

104 kA

Notes:

1. Maximum voltage for which the breaker is designed and upper limit of operation.

2. At system operating voltages equal to or less than rated maximum voltage.

Closing and Latching Current

The function of any circuit breaker is to close and stay

latched, during which the breaker goes through a first-

cycle maximum asymmetrical rms current. In common

applications, the standard close and latch capability meets

the requirements and specification of the circuit.

However, in certain applications that can include large

motor loads, the first-cycle asymmetrical short-circuit

current exceeds the closing and latching capabilities of the

selected breaker. If this situation arises, the circuit breaker

selection will be based, in most cases, on the closing and

latching capability of the next higher short-circuit current.

The closing and latching capability (kA, rms) of the circuit

breaker is expressed in peak amperes. The value is equal to

2.6 times rated short-circuit current for 60 Hz and 2.5 times

for 50 Hz.

Continuous Current

To select the proper SecoVac VB2+ breaker, calculate the

continuous current duty based on the loads of the feeders

and main breaker and identify a continuous current rating

equal to or greater than the load current.

SecoVac circuit breakers are 100% rated with no

continuous overload rating. For special applications with

long-time overload rating such as motors, generators or

transformers, it is important to consider that all of the

switchgear equipment (including circuit breakers) must

have a continuous current rating at least equal to the

overload rating of the special apparatus. Consult ANSI

C37.20.2 for overload current capability guidelines.

Rated Interrupting Time

SecoVac VB2+ circuit breakers are available only with

interrupting ratings of 3 cycles, as stated in Table 2-1.

Duty Cycle

SecoVac VB2+ circuit breakers have a rated duty cycle of

O - 0.3s – CO - 180s – CO.

SPECIAL SWITCHING APPLICATIONS

Application of power circuit breakers for switching duty

may require derating of the circuit breaker, or increased

maintenance. SecoVac VB2+ circuit breakers do not require

derating when applied in automatic reclosing duty. For

these applications, like capacitor switching, the usual

practice is to first select a circuit breaker based on the

criteria provided under “Selection Considerations,” above.

Then, consider the switching duty and, if necessary, re-

determine the circuit breaker capabilities (continuous-

current rating, interrupting rating, etc.). Also, factor in any

modified operating or maintenance requirements.

Recheck the circuit breaker’s evaluation capabilities

against all the basic duty requirements under “Selection

Considerations.” If the circuit breaker selected initially, and

as derated (or otherwise modified), no longer meets the

duty requirements of the application, choose the next-

higher-rated breaker. Repeat the derating or rating

adjustment process to confirm that the new breaker has

adequate capability.

Automatic Transfer

To improve system reliability and ensure supply to critical

loads, primary or secondary selective system designs are

often utilized. In these configurations, two or more

otherwise typical radial buses are connected together via

SecoGear Medium-voltage Switchgear Application and Technical Guide DET-882

Circuit Breaker Selection

tie breakers. In normal operating mode, each bus is served

by its own source through normally closed main breakers,

with the bus tie breaker open. If an outage occurs on one

of the incoming supplies, the incoming breaker connected

to that supply is opened, and then the bus is re-energized

by closing the bus tie breaker to transfer the dead bus to

the live (alternate) source.

To protect against damage to motors connected to the

dead bus, the bus tie breaker is typically not allowed to

close until the residual voltage on the effected bus has

decayed to a safe level. After the lost source has been

reestablished, the scheme provides two methods (auto and

manual) to restore the system to normal configuration.

If the sources cannot be synchronized, the bus tie breaker

must be manually opened before the open incomer can be

manually closed. In this procedure, the incomer will be

allowed to close only if the incoming source (line VT)

voltage is above a “live” threshold and the load (bus VT)

voltage is below a “dead” threshold value.

If the sources are synchronized, it is possible to manually

close the open incomer with synch check supervision to

parallel all three breakers. The scheme will then

automatically open a breaker which had been previously

selected to trip if all breakers become closed, in this

instance the bus tie breaker. Note that if momentary

paralleling is utilized, the equipment and breakers must be

rated for the total available fault current from the

combined sources.

The detection of an undervoltage event and the resulting

transfer logic can be accomplished using either discrete

protective relays, auxiliary relays and timers, or with a PLC

and programming, or by using the various protective relay

and logic features contained in today’s multifunction

relays, such as GE Multilin SR850. In addition to a protective

relay required for each of the three circuit breakers (both

mains and the tie), it is required to connect one contact

from a three-position switch to each breaker. This switch

(device 43/10) is used to select the breaker that will trip

after all breakers are closed. It is generally recommended

that a two-position switch (device 43/83) with three

contacts, be connected to each relay as an “Auto-Off”

transfer scheme selector.

Because a relay is required for each the three circuit

breakers, it allows bus-splitting. This operation is

accomplished by setting the time overcurrent elements in

the relay on the bus tie breaker to trip faster than the

incomers, opening the bus tie before an incomer when

operating from only one source.

Capacitor Switching

Capacitor banks are generally applied on both utility and

industrial power systems to improve voltage regulation

and system stability. SecoVac VB2+ circuit breakers

properly equipped are applicable as circuit breakers for

small shunt-capacitor-bank switching applications.

Table 2-2: SecoVac Breaker

Capacitor Switching Capabilities

Rated Max. Voltage

15 kV RMS

Rated Short-circuit Current

31.5 kV RMS

Single Bank Rated Capacitor Breaking

Current (1200 A Breaker)

250 A

Switching Class

Frequency

60 Hz

SERVICE CONDITIONS

ANSI defines specific service conditions as “usual” or

“unusual” for the operation of metal-clad switchgear;

based on factors such as altitude, temperature, humidity

and a variety of others, like presence of atmospheric

contaminants storage conditions and tamper resistance.

ANSI C37.04 specifies service conditions for circuit breakers

and ANSI C37.20.2 for metal-clad switchgear.

Usual Service Conditions

SecoVac VB2+ circuit breakers and the complete SecoGear

switchgear assembly are designed for usual service

conditions at their standard nameplate ratings;

•Ambient temperature range: maximum 40 °C [104 °F]

and minimum -30°C [-22 °F]

•Altitude: maximum 1000 m [3300 feet]

Unusual Service Conditions

Abnormal Temperature

For special applications with unusual service conditions

such as ambient temperature outside normal range (-30 °C

[-22 °F] to 40 °C [104 °F], consult ANSI C37.20.2 for derating

values applicable. Refer special or abnormal applications to

GE for evaluation.

Temperature Rise

The temperature of the buses and bolted connections in

any switchgear assembly must not exceed 65 °C [149 °F]

when operating under full load current, and the total hot

spot must not exceed 105 °C [221 °F], as stated in ANSI

C37.20.2. Connections to insulated cables must not exceed

a 45 °C [113 °F] temperature rise, and an 85 °C [185 °F] hot

spot temperature when operated at rated continuous

current in rms amperes at rated frequency.

High Altitude

There are two characteristics to take into consideration

when designing medium voltage metal-clad switchgear at

altitudes above 1000 meters [3300 ft]: continuous current

rating and dielectric withstand capability. Both of them use

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