Basler BE1-59NC User manual

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Publication: 9 2794 00 990
Revision: A 01/98

i
W A R N I N G !
To avoid personal injury or equipment damage, only
qualified personnel should perform the procedures
presented in this manual.
INTRODUCTION
This Instruction Manual provides information concerning the
operationandinstallationoftheBE1-59NCNeutralOvervoltageRelay.
To accomplish this, the following is provided.
Specifications
Functional characteristics
Mounting Information
Connections
Testing
REV A
ECA 14472

ii
CONFIDENTIAL INFORMATION
OF BASLER ELECTRIC COMPANY, HIGHLAND, IL. IT IS LOANED FOR
CONFIDENTIAL USE, SUBJECT TO RETURN ON REQUEST, AND WITH THE
MUTUAL UNDERSTANDING THAT IT WILL NOT BE USED IN ANY MANNER
DETRIMENTAL TO THE INTEREST OF BASLER ELECTRIC COMPANY.
First Printing: April 1994
Printed in USA
September 1994
It is not the intention of this manual to cover all details and variations
in equipment, nor does this manual provide data for every possible
contingency regarding installation or operation. The availability and
design of all features and options are subject to modification without
notice. Should further information be required, contact Basler
Electric Company, Highland, Illinois.
BASLER ELECTRIC, BOX 269 HIGHLAND, IL 62249 USA
PHONE [phone] FAX [phone]

iii
CONTENTS
Section 1 GENERAL INFORMATION 1-1
General ................................................ 1-1
Application .............................................. 1-1
Capacitor Bank Switching ............................... 1-1
Protection ........................................... 1-1
Input Sensing ........................................ 1-2
Alarms And Outputs ................................... 1-3
Model and Style Number Description ......................... 1-3
Sample Style Number .................................. 1-3
Style Number Identification Chart ......................... 1-4
Specifications ........................................... 1-4
Characteristic Curves ..................................... 1-6
Section 2 CONTROLS AND INDICATORS 2-1
Section 3 FUNCTIONAL DESCRIPTION 3-1
General ................................................ 3-1
Functional Description ..................................... 3-1
Inputs .............................................. 3-1
Filters .............................................. 3-1
Overvoltage Comparator ................................ 3-2
Definite Time Delay ................................... 3-2
Inverse Time Delay .................................... 3-2
Reference voltage Circuit ............................... 3-2
Power Supply ........................................ 3-2
Power Supply Status Contacts ........................... 3-2
Target Indicator Circuits ................................ 3-2
Section 4 INSTALLATION 4-1
General ................................................ 4-1
Relay Operating Precautions ............................... 4-1
Dielectric Test ........................................... 4-1
Relay Mounting .......................................... 4-1
Connections ............................................ 4-8
Section 5 TESTING 5-1
General ................................................ 5-1
Equipment Required ...................................... 5-1
Operational Test ......................................... 5-1
E2 Timing Option ..................................... 5-1
Typical Test Setup Timing Option E2 ...................... 5-2
Typical Test Setup Timing Option D1 Or D2 ................. 5-3
D1 Timing Option ..................................... 5-4
D2 Timing Option ..................................... 5-6

iv
CONTENTS - Continued
Section 6 MAINTENANCE 6-1
General ................................................ 6-1
Storage ................................................ 6-1
Test Plug ............................................... 6-1
Section 7 MANUAL CHANGE INFORMATION 7-1

1-1
SECTION 1
GENERAL INFORMATION
GENERAL
BE1-59NC Neutral Overvoltage Relays provide sensitive protection for capacitor banks. There are three
common types of capacitor bank failures that BE1-59NC Neutral Overvoltage Relays recognize. They are:
Unit dielectric failure.
Capacitor bank insulator failure.
Blown fuses.
BE1-59NC Neutral Overvoltage Relays protect for overvoltages due to internal voltage shifts that occur as
a result of these types of failures.
APPLICATION
Capacitor banks are widely used by utilities to maintain specified system voltage. Addition of capacitive
loads at appropriate points on the system compensate for heavy inductive loading that normally tends to
reduce voltage. This adding of leading megavars to compensate for the lagging megavar component of
electric loads is frequently referred to as power factor correction. Capacitor banks must be switched in
response to actual load conditions in order to obtain maximum power factor correction benefits.
Capacitor Bank Switching
One of the common methods of maximizing capacitor bank benefits is by evaluating the bus voltage. A
bandwidth surrounding the desired bus voltage level is established. When the bus voltage falls below the
bandwidth level, the capacitor bank is switched into the circuit. When the bus voltage rises above the
bandwidth level, the capacitor bank is switched out.
Protection
Protection of capacitor banks has always been difficult. It is especially difficult to sense failures inside the
capacitor banks because of the configuration. Experience indicates that most capacitor bank faults involve
one or more insulator failures with arcing across groups and/or phase-to-phase inside the bank. In most
cases, these types of faults are not seen by the bus differential or other protection unless the arcing spills
over to the area between the fuses and the circuit switcher. A fault across an insulator usually means that
one or more groups of parallel units are shorted. This will cause a neutral shift and unbalanced phase
currents. Unbalancedphasecurrentmagnitudesaredeterminedbythenumberofseriesconnectedgroups.
For full phase-to-neutral flashover, the maximum phase current is three times normal capacitor bank load
in the faulted phase.
Onemainprotection concern isovervoltagecascading. Acapacitorbankis unique inthatcascadingofunits
may take place after a predetermined number of unit fuses haveoperated. Normally aftera fuse has blown
in any other type of equipment, the faulted apparatus is disconnected and usually does not affect any
remaining equipment that is in service. That is not so with a capacitor bank. Each fuse that blows to isolate
the faulted unit sets up an increased voltage stress on the remaining units (Figure 1-1). Sometime later, the
nextweakestunit in thatgroupfails. As each successivefuseblows,thevoltage increases anotherstepand
rapidly causes the next unit to fail. Cascading takes place and results in serious damage to the capacitor
bankandpossiblehazardstopersonnel. Whilethecapacitorbankisfailing,thestationinminimallyaffected.

BE1-59NC General Information
1-2
The voltage is nearly normal, the current flow is almost unaffected, and station relay protection is not taking
any action until the failure has developed into a phase-to-phase or phase-to-ground fault.
A solution was to develop a protective scheme for the capacitor bank with the main emphasis on preventing
overvoltage cascading. To do this, a ground fault relay or neutral shift device had to be developed that was
sensitive enough to detect blown fuses for both alarming and tripping purposes. The best place to obtain
the sensing information is between the neutral of the capacitor bank and ground. Voltage differentials
between the normal capacitor bank status and that of one blown fuse are very small. However, BE1-59NC
Neutral Overvoltage Relays are sensitive enough to differentiate between these conditions and act
decisively.
Figure 1-1. Ungrounded 3-Phase, 3-Wire System
Input Sensing
BE1-59NC Neutral Overvoltage Relays receive the input signal from voltage sensing devices connected
between the capacitor bank neutral and ground. These voltage sensing devices can be potential
transformers or resistor potential devices. Ideally, the voltage across each leg of a capacitor bank is
balanced, and the voltage from neutral to ground is zero. If a single capacitor fails and blows the protecting
fuse, an unbalanced condition occurs that shifts the neutral and creates a small but measurable voltage.
Through the potential sensing devices, the neutral relay senses this voltage unbalance and reacts to give
the appropriate signal (usually an alarm or trip depending on the voltage level).
Further loss of more capacitors increases the neutral voltage. The relay senses this voltage increase, and
reacts to give the appropriate signal. This signal is usually a trip depending on the voltage levels and how
the protection scheme is designed.

BE1-59NC General Information
1-3
Alarms And Outputs
Sensitive settings on the relay are used as an alarm to alert that a fuse has blown and maintenance is
required. They would be typically set at a level corresponding to the voltage rise caused by one blown fuse.
The second output would have a setting that would be set to trip the capacitor bank off the bus or line when
the voltage exceeds 110% of the nominal capacitor bank voltage. This setting depends on the capacitor
bank size and configuration.
MODEL AND STYLE NUMBER DESCRIPTION
BE1-59NC Neutral Overvoltage Relays electrical characteristics and operational features are defined by a
combination of letters and numbers that make up the style number. Model numbers BE1-59NC designate
the relay as a Basler Electric, Class 100, Relay. The model number, together with the style number,
describe the options included in a specific device, and appear on the front panel, drawout cradle, and inside
the case assembly. Upon receipt of a relay, be sure to check the style number against the requisition and
the packing list to ensure that they agree.
Sample Style Number
Style number identification chart (Figure 1-2) defines the electrical characteristics and operational features
includedinBE1-59NC Neutral OvervoltageRelays. Forexample,ifthe model numberoftherelaywasBE1-
59NC, and the style number was A5E-E2J-C0S1F, the device would have the following features:
A- Single-phase voltage
5- 120 Vac, 60 Hz, nominal 1 to 20 Vac pickup
E- Two output relays with normally open contacts
E2 - Two setpoints; setpoint 1, definite timing 00.0 to 99.9 seconds; setpoint 2, definite timing
00.0 to 99.9 seconds
J- 125 Vdc or 100/120 Vac power supply
C- Internally operated targets
O- None
S- Push-to-energize outputs
1- Two auxiliary output relays, two SPDT sets of contacts; one for setpoint 1 and one for
setpoint 2
F- Semi-flush mounting case

BE1-59NC General Information
1-4
Figure 1-2. Style Number Identification Chart
SPECIFICATIONS
BE1-59NC Neutral Overvoltage Relays have the following features and capabilities.
Voltage Sensing Inputs Maximum continuous rating: 360 Vac for 100/120 Vac input, 480 Vac for
200/240 Vac input, with a maximum burden of 2 VA.
Sensing Input Ranges
Ranges 1 and 5 1 to 20 Vac pickup
Ranges 2 and 6 10 to 50 Vac pickup
Ranges 3 and 7 2 to 40 Vac pickup
Ranges 4 and 8 20 to 100 Vac pickup

BE1-59NC General Information
1-5
Pickup Accuracy
Ranges 1, 3, 5, or 7 ±2.0% or 100 millivolts, whichever is greater.
Ranges 2, 4, 6, or 8 ±2.0% or 200 millivolts, whichever is greater.
Dropout 98% of pickup within 7 cycles.
Timing Characteristics
Inverse Responsetimedecreasesasthedifferencebetweenthemonitoredvoltage
and the setpoint increases. The inverse time characteristics switch is
adjustable from 01 to 99 in 01 increments. Each position corresponds to
a specific curve except 00, which is instantaneous.
Definite Adjustable from 00.1 to 99.9 seconds, in steps of 0.1 seconds. Accuracy
is within 2.0 % or 100 milliseconds, whichever is greater. (A setting of 00.0
provides instantaneous timing.)
Accuracy Within±5%or25.0milliseconds(whicheverisgreater)oftheindicatedtime
for any combination of the time dial and within ±2% of the voltage
magnitude or 100 millivolts (for the 100/120 Vac sensing ranges) or 200
millivolts (for the 200/240 Vac sensing ranges) (whichever is greater) from
the actual pickup value. Inverse time is repeatable within ±2% or 25.0
milliseconds (whichever is greater) for any time dial or pickup setting.
Power Supply Refer to Table 1-1.
Table 1-1. Power Supply Specifications.
Type Nominal Input
Voltage
Input
Voltage
Range
Burden
at
Nominal
J 125 Vdc
120 Vac 62 to 150 Vdc 90 to 132 Vac 7.5 W 15.0 W
K 48 Vdc 24 to 60 Vdc 7.0 W
†L 24 Vdc 12 to 32 Vdc 7.5 W
‡Y 48 Vdc
125 Vdc 24 to 60 Vdc 62 to 150 Vdc 7.0 W 7.5 W
Z 250 Vdc
230 Vac 140 to 280 Vdc 190 to 270 Vac 12.0 W 33.5 VA
NOTES:
†Type L Power Supply may require 14 Vdc to begin operation.
Once operating, the voltage may be reduced to 12 Vdc.
‡Type Y Power Supply is field selectable for 48 or 125 Vdc.
Selection must be implemented at time of installation. This Power
Supply option is factory set for 125 Vdc.
Output Contacts Output contacts are rated as follows:
Resistive:
120/240 Vac Make 30 A for 0.2 seconds, carry 7 A continuously, and break 7 A.
250 Vdc Make and carry 30 A for 0.2 seconds, carry 7 A continuously, and break
0.3 A.
500 Vdc Make and carry 15 A for 0.2 seconds, carry 7 A continuously, and break