Engineering Procedure
Electrical
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EP 19 00 00 03 SP
COMMISSIONING OF TRANSLAY
PILOT WIRE PROTECTION SCHEME
Version 2.1
Issued April 2013
Owner: Chief Engineer, Electrical
Approved
by:
Neal Hook
Chief Engineer
Electrical
Authorised
by:
Neal Hook
Chief Engineer
Electrical
Disclaimer
This document was prepared for use on the RailCorp Network only.
RailCorp makes no warranties, express or implied, that compliance with the contents of this document shall be
sufficient to ensure safe systems or work or operation. It is the document users sole responsibility to ensure that the
copy of the document it is viewing is the current version of the document as in use by RailCorp.
RailCorp accepts no liability whatsoever in relation to the use of this document by any party, and RailCorp excludes
any liability which arises in any manner by the use of this document.
Copyright
The information in this document is protected by Copyright and no part of this document may be reproduced, altered,
stored or transmitted by any person without the prior consent of RailCorp.
UNCONTROLLED WHEN PRINTED Page 1 of 6
RailCorp Engineering Procedure Electrical
Commissioning of Translay Pilot Wire Protection Scheme EP 19 00 00 03 SP
RailCorp Page 2 of 6
Issued April 2013 UNCONTROLLED WHEN PRINTED Version 2.1
Document control
Version Date Summary of change
August 2002 Last Technical Review
2.0 May 2010 Application of TMA 400 format
2.1 April 2013 Update template
RailCorp Engineering Procedure Electrical
Commissioning of Translay Pilot Wire Protection Scheme EP 19 00 00 03 SP
RailCorp Page 3 of 6
Issued April 2013 UNCONTROLLED WHEN PRINTED Version 2.1
Contents
1 Introduction .............................................................................................................................4
2 Scope and Application ...........................................................................................................4
3 Definitions & Abbreviations ...................................................................................................5
4 Pre-Commissioning Procedure .............................................................................................5
5 Commissioning Procedure ....................................................................................................5
5.1 Pilot Circuit Measurements and Testing...................................................................................5
5.2 HMB4 Loop Resistance Compensation and Sensitivity............................................................5
5.3 Supervision Relay Adjustment..................................................................................................5
5.4 Verifying Phasing Between Substations ...................................................................................5
6 Post Commissioning Procedure ...........................................................................................6
6.1 Verifying Failure Alarms............................................................................................................6
6.2 Supervision Relay Re-Adjustment............................................................................................6
7 Data Set associated with the Equipment ..............................................................................6
RailCorp Engineering Procedure Electrical
Commissioning of Translay Pilot Wire Protection Scheme EP 19 00 00 03 SP
1 Introduction 1 Introduction
The most common type of unit protection used on the RailCorp high voltage network is
Translay pilot wire protection. This publication sets out the general requirements for the
testing and the recording of test results during the commissioning of a new Translay pilot
wire protection scheme. The relevant sections of this publication shall also apply when an
existing Translay pilot wire protection scheme is re-commissioned following any
alterations to the system.
The most common type of unit protection used on the RailCorp high voltage network is
Translay pilot wire protection. This publication sets out the general requirements for the
testing and the recording of test results during the commissioning of a new Translay pilot
wire protection scheme. The relevant sections of this publication shall also apply when an
existing Translay pilot wire protection scheme is re-commissioned following any
alterations to the system.
2 Scope and Application 2 Scope and Application
Translay protection schemes exist throughout the RailCorp high voltage network and
are a very important element in the overall protection of the high voltage system.
Translay protection schemes exist throughout the RailCorp high voltage network and
are a very important element in the overall protection of the high voltage system.
The most common Translay scheme used in the RailCorp network is that using HMB4
relays made by GEC Alsthom. Refer to Figure 1. These relays use the output of current
transformers (CTs) to represent the 3 phase currents in the form of a single phase
voltage. The voltages produced by each relay are proportional to the current flowing in
the transmission line being protected. A relay is installed on each end of the line. Under
normal conditions, the voltages produced by the HMB4 relay at each end of the feeder
should have the same magnitude and phase and negligible ac current should flow around
the pilot circuit.
The most common Translay scheme used in the RailCorp network is that using HMB4
relays made by GEC Alsthom. Refer to
Figure 1. These relays use the output of current
transformers (CTs) to represent the 3 phase currents in the form of a single phase
voltage. The voltages produced by each relay are proportional to the current flowing in
the transmission line being protected. A relay is installed on each end of the line. Under
normal conditions, the voltages produced by the HMB4 relay at each end of the feeder
should have the same magnitude and phase and negligible ac current should flow around
the pilot circuit.
C.T. 1 C.T. 2
Feeder
RailCorp Page 4 of 6
Issued April 2013 UNCONTROLLED WHEN PRINTED Version 2.1
Figure 1 - HMB4 pilot wire scheme between two substations Figure 1 - HMB4 pilot wire scheme between two substations
Note: Pilot wire relay detects faults between CT1 and CT2 only. Note: Pilot wire relay detects faults between CT1 and CT2 only.
When a fault occurs on a feeder, ac current flows in the pilots due to the imbalance of the
currents at each end and the corresponding difference in pilot voltage produced by each
relay.
When a fault occurs on a feeder, ac current flows in the pilots due to the imbalance of the
currents at each end and the corresponding difference in pilot voltage produced by each
relay.
A d.c. pilot supervision current does, however, normally flow around the pilot circuit. This
is injected onto the pilots at a pilot isolation transformer at one of the substations. The
substation at which the current is injected is referred to as the sending end substation.
A d.c. pilot supervision current does, however, normally flow around the pilot circuit. This
is injected onto the pilots at a pilot isolation transformer at one of the substations. The
substation at which the current is injected is referred to as the sending end substation.
In addition, RailCorp has adopted the practice of installing current check relays in pilot
wire schemes. By installing the trip contacts of these current check relays in series with
the trip contacts of the HMB4 relays, the circuit breakers are then only operated when
both relays detect a fault. This practice effectively ensures that no ACCB trips arise from
the pilots being tampered with or failing.
In addition, RailCorp has adopted the practice of installing current check relays in pilot
wire schemes. By installing the trip contacts of these current check relays in series with
the trip contacts of the HMB4 relays, the circuit breakers are then only operated when
both relays detect a fault. This practice effectively ensures that no ACCB trips arise from
the pilots being tampered with or failing.
Hence an ACCB will only trip if the HMB4 operates and the fault current is of sufficient
magnitude to pick-up the current check relays.
Hence an ACCB will only trip if the HMB4 operates and the fault current is of sufficient
magnitude to pick-up the current check relays.
Substation No.2
Substation No.1
Isolation
transformer
Pilot wires
Isolation
transformer
HMB4
& check
rela
HMB4
& check
rela ys ys
RailCorp Engineering Procedure Electrical
Commissioning of Translay Pilot Wire Protection Scheme EP 19 00 00 03 SP
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Issued April 2013 UNCONTROLLED WHEN PRINTED Version 2.1
3 Definitions & Abbreviations
ACCB Alternating Current Circuit Breaker
CT Current Transformer
EOC Electrical Operating Centre
4 Pre-Commissioning Procedure
In substations where one bus section ACCB provides protection for two feeders, a check
shall be carried out to ensure the connections between the bus section and the rectifier
current transformers are correct.
5 Commissioning Procedure
5.1 Pilot Circuit Measurements and Testing
Measure and record the pilot insulation resistance.
Pilot no.1 to earth.
Pilot no.2 to earth.
Pilot no.1 to Pilot no.2.
The insulation resistance shall be greater than 5 M.
Measure and record the pilot circuit capacitance. The pilot capacitance shall be in the
order of 0.05 F/km.
Measure and record the pilot loop resistance.
5.2 HMB4 Loop Resistance Compensation and Sensitivity
Compensation shall be set on the HMB4 relay to ensure the relay is working within its
designed loop resistance of 1000 .
5.3 Supervision Relay Adjustment
Adjust the SJ A pilot supervision unit to ensure that the output from its Wheatstone bridge
circuit is at a minimum under normal pilot conditions. The voltage shall be set as close to
zero as possible achievable, at least within 20 mV.
Measure and record the voltage from the SJ A pilot supervision unit.
5.4 Verifying Phasing Between Substations
Tests shall be conducted to verify that, for each phase, current entering the feeder at one
end and leaving the feeder at the other results in the output of both HMB4 relays being of
essentially the same phase and magnitude.
RailCorp Engineering Procedure Electrical
Commissioning of Translay Pilot Wire Protection Scheme EP 19 00 00 03 SP
RailCorp Page 6 of 6
Issued April 2013 UNCONTROLLED WHEN PRINTED Version 2.1
6 Post Commissioning Procedure
6.1 Verifying Failure Alarms
Verify, and record, by means of simulated failures, such as opening links and fuses, all
relevant alarms and flags, including:
pilot circuit failure relay flag
open pilot alarm at EOC
supervisory supply failure relay flag
HMB4 flags
current check relay flag
6.2 Supervision Relay Re-Adjustment
Check and record the dc voltage across the test terminals of the supervision relay to
ensure that the voltage has not changed significantly.
Adjust and record the voltage if the potentiometer is required to be readjusted for
minimum dc voltage.
7 Data Set associated with the Equipment
The results of the Pre-commissioning, Commissioning and Post Commissioning
procedures shall be recorded and maintained by the Maintenance Provider responsible
for the installation in which the pilot wire protection equipment is installed. These results
include:
Pilot insulation resistance;
o Pilot no. 1 to earth;
o Pilot no. 2 to earth;
o Pilot no. 1 to Pilot no. 2;
Pilot circuit capacitance;
Pilot loop resistance;
SJ A pilot supervision voltage;
Verification of alarms and flags;
pilot circuit failure relay flag;
open pilot alarm at EOC;
o supervisory supply failure relay flag;
o HMB4 flags;
o current check relay flag;
o Supervision relay dc test voltage.
