Micom P721 Quick start guide

MiCOM P721 & P723
High Impedance Differential Protection
P72x/EN T/C21
Software Version 11.D
Technical Guide

Technical Guide P72x/EN T/C21
Contents
MiCOM P721/723 Page 1/2
MiCOM P721 & P723
HIGH IMPEDANCE DIFFERENTIAL PROTECTION
TECHNICAL GUIDE
CONTENTS
Safety Section Pxxxx/EN SS/G11
Introduction P72x/EN IT/C21
Handling, Installation and Case Dimensions P72x/EN IN/C21
User Guide P72x/EN FT/C21
Menu Content Tables P72x/EN HI/C21
Technical Data P72x/EN TD/A11
Getting Started P72x/EN GS/C21
Application P72x/EN AP/C21
Communication Database P72x/EN CT/A11
Commissioning and Maintenance Guide P72x/EN CM/C21
Connection Diagrams P72x/EN CO/A11
Commissioning Test & Records Sheets P72x/EN RS/A11
Hardware/Software Version History and Compatibility P72x/EN VC/C21

P72x/EN T/C21 Technical Guide
Contents
Page 2/2
MiCOM P721/P723
BLANK PAGE

Pxxx/EN SS/G11
SAFETY SECTION

Pxxx/EN SS/G11
Safety Section Page 1/8
STANDARD SAFETY STATEMENTS AND EXTERNAL
LABEL INFORMATION FOR SCHNEIDER ELECTRIC
EQUIPMENT
1. INTRODUCTION 3
2. HEALTH AND SAFETY 3
3. SYMBOLS AND EXTERNAL LABELS ON THE EQUIPMENT 4
3.1 Symbols 4
3.2 Labels 4
4. INSTALLING, COMMISSIONING AND SERVICING 4
5. DECOMMISSIONING AND DISPOSAL 7
6. TECHNICAL SPECIFICATIONS FOR SAFETY 8
6.1 Protective fuse rating 8
6.2 Protective Class 8
6.3 Installation Category 8
6.4 Environment 8

Pxxx/EN SS/G11
Page 2/8 Safety Section
BLANK PAGE

Pxxx/EN SS/G11
Safety Section Page 3/8
1. INTRODUCTION
This guide and the relevant equipment documentation provide full information on safe
handling, commissioning and testing of this equipment. This Safety Guide also includes
descriptions of equipment label markings.
Documentation for equipment ordered from Schneider Electric is despatched separately from
manufactured goods and may not be received at the same time. Therefore this guide is
provided to ensure that printed information which may be present on the equipment is fully
understood by the recipient.
The technical data in this safety guide is typical only, see the technical data section of the
relevant product publication(s) for data specific to a particular equipment.
Before carrying out any work on the equipment the user should be familiar with the
contents of this Safety Guide and the ratings on the equipment’s rating label.
Reference should be made to the external connection diagram before the equipment is
installed, commissioned or serviced.
Language specific, self-adhesive User Interface labels are provided in a bag for some
equipment.
2. HEALTH AND SAFETY
The information in the Safety Section of the equipment documentation is intended to ensure
that equipment is properly installed and handled in order to maintain it in a safe condition.
It is assumed that everyone who will be associated with the equipment will be familiar with
the contents of that Safety Section, or this Safety Guide.
When electrical equipment is in operation, dangerous voltages will be present in certain parts
of the equipment. Failure to observe warning notices, incorrect use, or improper use may
endanger personnel and equipment and also cause personal injury or physical damage.
Before working in the terminal strip area, the equipment must be isolated.
Proper and safe operation of the equipment depends on appropriate shipping and handling,
proper storage, installation and commissioning, and on careful operation, maintenance and
servicing. For this reason only qualified personnel may work on or operate the equipment.
Qualified personnel are individuals who:
• Are familiar with the installation, commissioning, and operation of the equipment and
of the system to which it is being connected;
• Are able to safely perform switching operations in accordance with accepted safety
engineering practices and are authorised to energize and de-energize equipment and
to isolate, ground, and label it;
• Are trained in the care and use of safety apparatus in accordance with safety
engineering practices;
• Are trained in emergency procedures (first aid).
The equipment documentation gives instructions for its installation, commissioning, and
operation. However, the manual cannot cover all conceivable circumstances or include
detailed information on all topics. In the event of questions or specific problems, do not take
any action without proper authorization. Contact the appropriate Schneider Electric technical
sales office and request the necessary information.

Pxxx/EN SS/G11
Page 4/8 Safety Section
3. SYMBOLS AND EXTERNAL LABELS ON THE EQUIPMENT
For safety reasons the following symbols and external labels, which may be used on the
equipment or referred to in the equipment documentation, should be understood before the
equipment is installed or commissioned.
3.1 Symbols
Caution: refer to equipment documentation Caution: risk of electric shock
Protective Conductor (*Earth) terminal
Functional/Protective Conductor (*Earth)
terminal.
Note: This symbol may also be used for a
Protective Conductor (Earth) Terminal if that
terminal is part of a terminal block or sub-
assembly e.g. power supply.
*NOTE: THE TERM EARTH USED THROUGHOUT THIS GUIDE IS THE
DIRECT EQUIVALENT OF THE NORTH AMERICAN TERM
GROUND.
3.2 Labels
See Safety Guide (SFTY/4L M/G11) for equipment labelling information.
4. INSTALLING, COMMISSIONING AND SERVICING
Equipment connections
Personnel undertaking installation, commissioning or servicing work for this
equipment should be aware of the correct working procedures to ensure safety.
The equipment documentation should be consulted before installing,
commissioning, or servicing the equipment.
Terminals exposed during installation, commissioning and maintenance may
present a hazardous voltage unless the equipment is electrically isolated.
The clamping screws of all terminal block connectors, for field wiring, using M4
screws shall be tightened to a nominal torque of 1.3 Nm.
Equipment intended for rack or panel mounting is for use on a flat surface of a
Type 1 enclosure, as defined by Underwriters Laboratories (UL).
Any disassembly of the equipment may expose parts at hazardous voltage, also
electronic parts may be damaged if suitable electrostatic voltage discharge (ESD)
precautions are not taken.
If there is unlocked access to the rear of the equipment, care should be taken by
all personnel to avoid electric shock or energy hazards.
Voltage and current connections shall be made using insulated crimp terminations
to ensure that terminal block insulation requirements are maintained for safety.
Watchdog (self-monitoring) contacts are provided in numerical relays to indicate
the health of the device. Schneider Electric strongly recommends that these
contacts are hardwired into the substation's automation system, for alarm
purposes.

Pxxx/EN SS/G11
Safety Section Page 5/8
To ensure that wires are correctly terminated the correct crimp terminal and tool
for the wire size should be used.
The equipment must be connected in accordance with the appropriate connection
diagram.
Protection Class I Equipment
- Before energizing the equipment it must be earthed using the protective
conductor terminal, if provided, or the appropriate termination of the
supply plug in the case of plug connected equipment.
- The protective conductor (earth) connection must not be removed since
the protection against electric shock provided by the equipment would be
lost.
- When the protective (earth) conductor terminal (PCT) is also used to
terminate cable screens, etc., it is essential that the integrity of the
protective (earth) conductor is checked after the addition or removal of
such functional earth connections. For M4 stud PCTs the integrity of the
protective (earth) connections should be ensured by use of a locknut or
similar.
The recommended minimum protective conductor (earth) wire size is 2.5 mm²
(3.3 mm² for North America) unless otherwise stated in the technical data section
of the equipment documentation, or otherwise required by local or country wiring
regulations.
The protective conductor (earth) connection must be low-inductance and as short
as possible.
All connections to the equipment must have a defined potential. Connections that
are pre-wired, but not used, should preferably be grounded when binary inputs
and output relays are isolated. When binary inputs and output relays are
connected to common potential, the pre-wired but unused connections should be
connected to the common potential of the grouped connections.
Before energizing the equipment, the following should be checked:
- Voltage rating/polarity (rating label/equipment documentation),
- CT circuit rating (rating label) and integrity of connections,
- Protective fuse rating,
- Integrity of the protective conductor (earth) connection (where
applicable),
- Voltage and current rating of external wiring, applicable to the application.
Accidental touching of exposed terminals
If working in an area of restricted space, such as a cubicle, where there is a risk of
electric shock due to accidental touching of terminals which do not comply with
IP20 rating, then a suitable protective barrier should be provided.
Equipment use
If the equipment is used in a manner not specified by the manufacturer, the
protection provided by the equipment may be impaired.
Removal of the equipment front panel/cover
Removal of the equipment front panel/cover may expose hazardous live parts,
which must not be touched until the electrical power is removed.

Pxxx/EN SS/G11
Page 6/8 Safety Section
UL and CSA/CUL Listed or Recognized equipment
To maintain UL and CSA/CUL Listing/Recognized status for North America the
equipment should be installed using UL or CSA Listed or Recognized parts for
the following items: connection cables, protective fuses/fuseholders or circuit
breakers, insulation crimp terminals and replacement internal battery, as
specified in the equipment documentation.
For external protective fuses a UL or CSA Listed fuse shall be used. The Listed
type shall be a Class J time delay fuse, with a maximum current rating of 15 A
and a minimum d.c. rating of 250 Vd.c., for example type AJT15.
Where UL or CSA Listing of the equipment is not required, a high rupture
capacity (HRC) fuse type with a maximum current rating of 16 Amps and a
minimum d.c. rating of 250 Vd.c. may be used, for example Red Spot type NIT or
TIA.
Equipment operating conditions
The equipment should be operated within the specified electrical and
environmental limits.
Current transformer circuits
Do not open the secondary circuit of a live CT since the high voltage produced
may be lethal to personnel and could damage insulation. Generally, for safety,
the secondary of the line CT must be shorted before opening any connections to
it.
For most equipment with ring-terminal connections, the threaded terminal block
for current transformer termination has automatic CT shorting on removal of the
module. Therefore external shorting of the CTs may not be required, the
equipment documentation should be checked to see if this applies.
For equipment with pin-terminal connections, the threaded terminal block for
current transformer termination does NOT have automatic CT shorting on removal
of the module.
External resistors, including voltage dependent resistors (VDRs)
Where external resistors, including voltage dependent resistors (VDRs), are fitted
to the equipment, these may present a risk of electric shock or burns, if touched.
Battery replacement
Where internal batteries are fitted they should be replaced with the recommended
type and be installed with the correct polarity to avoid possible damage to the
equipment, buildings and persons.
Insulation and dielectric strength testing
Insulation testing may leave capacitors charged up to a hazardous voltage. At the
end of each part of the test, the voltage should be gradually reduced to zero, to
discharge capacitors, before the test leads are disconnected.
Insertion of modules and pcb cards
Modules and PCB cards must not be inserted into or withdrawn from the
equipment whilst it is energized, since this may result in damage.
Insertion and withdrawal of extender cards
Extender cards are available for some equipment. If an extender card is used,
this should not be inserted or withdrawn from the equipment whilst it is energized.
This is to avoid possible shock or damage hazards. Hazardous live voltages may
be accessible on the extender card.

Pxxx/EN SS/G11
Safety Section Page 7/8
External test blocks and test plugs
Great care should be taken when using external test blocks and test plugs such
as the MMLG, MMLB and MiCOM P990 types, hazardous voltages may be
accessible when using these. *CT shorting links must be in place before the
insertion or removal of MMLB test plugs, to avoid potentially lethal voltages.
*Note: When a MiCOM P992 Test Plug is inserted into the MiCOM P991 Test
Block, the secondaries of the line CTs are automatically shorted, making
them safe.
Fiber optic communication
Where fiber optic communication devices are fitted, these should not be viewed
directly. Optical power meters should be used to determine the operation or
signal level of the device.
Cleaning
The equipment may be cleaned using a lint free cloth dampened with clean water,
when no connections are energized. Contact fingers of test plugs are normally
protected by petroleum jelly, which should not be removed.
5. DECOMMISSIONING AND DISPOSAL
De-commissioning
The supply input (auxiliary) for the equipment may include capacitors across the
supply or to earth. To avoid electric shock or energy hazards, after completely
isolating the supplies to the equipment (both poles of any dc supply), the
capacitors should be safely discharged via the external terminals prior to
de-commissioning.
Disposal
It is recommended that incineration and disposal to water courses is avoided.
The equipment should be disposed of in a safe manner. Any equipment
containing batteries should have them removed before disposal, taking
precautions to avoid short circuits. Particular regulations within the country of
operation, may apply to the disposal of the equipment.

Pxxx/EN SS/G11
Page 8/8 Safety Section
6. TECHNICAL SPECIFICATIONS FOR SAFETY
Unless otherwise stated in the equipment technical manual, the following data is applicable.
6.1 Protective fuse rating
The recommended maximum rating of the external protective fuse for equipments is 16A,
high rupture capacity (HRC) Red Spot type NIT, or TIA, or equivalent. Unless otherwise
stated in equipment technical manual, the following data is applicable. The protective fuse
should be located as close to the unit as possible.
CAUTION - CTs must NOT be fused since open circuiting them may
produce lethal hazardous voltages.
6.2 Protective Class
IEC 60255-27: 2005
EN 60255-27: 2006
Class I (unless otherwise specified in the equipment
documentation). This equipment requires a protective
conductor (earth) connection to ensure user safety.
6.3 Installation Category
IEC 60255-27: 2005
EN 60255-27: 2006
Installation Category III (Overvoltage Category III):
Distribution level, fixed installation.
Equipment in this category is qualification tested at
5 kV peak, 1.2/50 µs, 500 Ω, 0.5 J, between all
supply circuits and earth and also between
independent circuits.
6.4 Environment
The equipment is intended for indoor installation and use only. If it is required for use in an
outdoor environment then it must be mounted in a specific cabinet or housing which will
enable it to meet the requirements of IEC 60529 with the classification of degree of
protection IP54 (dust and splashing water protected).
Pollution Degree - Pollution Degree 2 Compliance is demonstrated by reference
Altitude - Operation up to 2000m to safety standards.
IEC 60255-27:2005
EN 60255-27: 2006

Introduction P72x/EN IT/C21
MiCOM P721/P723
INTRODUCTION

Introduction P72x/EN IT/C21
MiCOM P721/P723 Page 1/10
CONTENTS
1. INTRODUCTION 3
2. HOW TO USE THIS MANUAL 4
3. INTRODUCTION TO THE MiCOM RANGE 5
4. INTRODUCTION TO THE MiCOM P721 & P723 PROTECTIONS 6
5. MAIN FUNCTIONS 7
5.1 Main functions 7
5.2 General functions 7
5.3 Ordering options 9

P72x/EN IT/C21 Introduction
Page 2/10 MiCOM P721/P723
BLANK PAGE

Introduction P72x/EN IT/C21
MiCOM P721/P723 Page 3/10
1. INTRODUCTION
The differential protections of the MiCOM P72x range are Schneider Electric numerical high
impedance differential protection. MiCOM P721 and P723 have been designed to provide
differential protection and a high impedance differential protection
The differential protection consists to measure the summation of n Current Transformers
(CTs) secondary currents. Without internal fault, this sum is null. If an internal fault occurs,
the protection measures the leak current. If an external fault occurs (with non-saturated CT),
the Kirchhoff's law is conserved and no current is measured.
The high impedance differential protection main application is a CT saturation in a busbar
(when a serious and external fault occurs).

P72x/EN IT/C21 Introduction
Page 4/10 MiCOM P721/P723
2. HOW TO USE THIS MANUAL
This manual provides a description of MiCOM P721 and P723 functions and settings. The
goal of this manual is to allow the user to become familiar with the application, installation,
setting and commissioning of these relays.
This manual has the following format:
P72x/EN IT Introduction
The introduction presents the documentation structure and a
brief presentation of the relay, including functions.
P72x/EN IN Handling, installation and case dimensions
This section provides logistics general instructions for handling,
installing and stocking..
P72x/EN FT User Guide
This section provides relay settings with a brief explanation of
each setting and detailed description. It also provides recording
and measurements functions including the configuration of the
event and disturbance recorder and measurement functions.
P72x/EN HI Menu content tables
This section shows the menu structure of the relays, with a
complete list of all of the menu settings.
P72x/EN AP Application Notes
This section includes a description of common power system
applications of the relay, calculation of suitable settings, some
typical worked examples, and how to apply the settings to the
relay.
P72x/EN TD Technical data and curve characteristics
This section provides technical data including setting ranges,
accuracy limits, recommended operating conditions, ratings and
performance data. Compliance with norms and international
standards is quoted where appropriate.
P72x/EN CT Communication database
This section provides an overview regarding the communication
interfaces of the relay. Detailed protocol mappings, semantics,
profiles and interoperability tables are not provided within this
manual. Separate documents are available per protocol,
available for download from our website.
P72x/EN CM Commissioning and Maintenance Guide
Instructions on how to commission the relay, comprising checks
on the calibration and functionality of the relay.
P72x/EN CO Connection diagrams
This section provides the mechanical and electrical description.
External wiring connections to the relay are indicated.
P72x/EN RS Commissioning test and records sheets
This section contains checks on the calibration and functionality
of the relay.
P72x/EN VC Hardware/Software version history and compatibility
History of all hardware and software releases for the product.