Table Of ContentPROTECTION
MiCOM P342, P343, P344
Generator Protection Relays
The MiCOM generator protection relays
provide flexible and reliable integration of
protection, control, monitoring and
measurement functions.
Extensive functionality is available to
provide complete protection and control
with three models for a wide range of
applications, covering most installations
MiCOM P343
from small generators up to sophisticated
Generator protection relay
systems.
The variable number of opto inputs and
output contacts available allow complex
protection schemes to be created using
the relay's powerful but easy to use
"Programmable Scheme Logic" (PSL).
A customer choice of industry standard
protocols are available on the relay,
facilitating an easier integration into both
new and existing network control
systems.
Customer Benefits
• Extensive protection
functionality to meet the
requirements for most
generator protection
applications
(cid:127)Programmable Scheme
Logic allows easy
customistaion of the
protection and control
functions
(cid:127)Flexible
communications
options with a number
of protocols and
communications ports
available
AREVA T&D
APPLICATION The MiCOM P343 is suitable for protection of larger or
more important generators, providing generator
The MiCOM P342 is suitable for protection of differential, 100% stator ground fault via a 3rd harmonic
generators which require cost effective high quality measuring technique, pole slipping and unintentional
protection.Protection includes overcurrent, ground energisation at standstill protection in addition to the
fault, neutral voltage displacement, sensitive or features of the P342.The P344 is similar to the P343
restricted ground fault, voltage dependent overcurrent but includes a second neutral voltage input for ground
or underimpedance, under and overvoltage, under and fault / interturn protection.
overfrequency, reverse, low forward or overpower, field
failure, negative phase sequence thermal, negative
phase sequence overcurrent and overvoltage, turbine
abnormal frequency, thermal and overfluxing, as well
as VT and CT supervision.
FUNCTIONS OVERVIEW P342 P343 P344
87 Differential - 1 1
Interturn (Split Phase) - 1 1
50/51/67 Directional / non directional, instantaneous/ 4 4 4
time delayed phase overcurrent
50N/51N Non directional, instantaneous 2 2 2
/ time delayed phase ground fault
67N/67W Sensitive directional earth fault / wattmetric ground fault 1 1 1
64 Restricted ground fault 1 1 1
51V Voltage dependent overcurrent 1 1 1
21 Underimpedance 2 2 2
59N Neutral voltage displacement/residual overvoltage, 2M/2D 2M/2D 2M/2M/
interturn - measured (M), derived (D) 2D
27/59 Under/Over voltage 2/2 2/2 2/2
81U/81O Under/Over frequency 2/4 2/4 2/4
81AB Turbine abnormal frequency 6 6 6
32R/32L/32O Reverse/Low Forward/Over power 2 2 2
40 Loss of field 2 2 2
46T Negative phase sequence thermal 2 2 2
46OC Directional / non directional, 4 4 4
negative phase sequence overcurrent
47 Negative phase sequence overvoltage 1 1 1
49 Stator thermal overload 2 2 2
24 Overfluxing 5 5 5
78 Pole slipping - 1 1
27TN/59TN 100% stator earth fault - 1 1
(3rd harmonic neutral under/over voltage)
50/27 Unintentional energisation at standstill - 1 1
50BF CB Fail 2 2 2
Current transformer supervision 1 1 1
Voltage transformer supervision 1 1 1
RTDs x 10 PT100 Option Option Option
CLIO (4 analogue inputs+4 analogue outputs) Option Option Option
IRIG-B Option Option Option
Front communications port (EIA(RS) 232 9-pin) 1 1 1
Rear communications port (EIA (RS)485 / K-Bus) 1 1 1
(COMM1)
Rear communications fibre optic port (COMM1) Option Option Option
2nd rear communications port (COMM2) Option Option Option
Opto Inputs 8-24 16-32 24-32
Output Contacts 7-24 14-32 24-32
2>3
GLOBAL FUNCTIONS
The following global functions are generally available in
all devices :
> 4 setting groups
> Metering
> Event recording
> Disturbance recording
> Fault recording
> Trip circuit supervision via PSL
> Breaker state and condition monitoring
MAIN PROTECTION FUNCTIONS
The main protection functions are autonomous and
can be individually enabled or disabled to suit a
particular application.Each protection function is
available in 4 separate setting groups which can be
individually enabled or disabled.
Three phase tripping with faulted phase indication is
Figure 1 Simple function selection by mouseclick
provided for all protection functions.
FUNCTIONAL OVERVIEW
Communication Self
COMM1 COMM2 Monitoring
to SCADA / substation control / RTU / modem ... Disturbance
via RS485 or Fibre optic using IEC60870-5-103, Recording
Modbus, DNP3.0, Courier on COMM1. COMM2 Metering
is RS485 / RS232 Courier only
.
59N
V
NEUTRAL2
VTS 2579 8811OU 81AB 24 47
V
INSENSITIVE
I2
67
64 87 CTS 5501 5211V 323R2/O32L 40 46T 5207 78 49 67N 50BF 46OC
I1
IN
VNEUTRAL1
59N 27TN 5501NN
P344 only
P343/4 only Generator Protection
RTDs CLIO always available P342 / P343 / P344
optional
(Description of ANSI code nos.see Functions Overview)
MiCOM P342/3/4 : Comprehensive protection
for all your generator protection requirements
> Generator differential (P343/4 only) > Phase overcurrent
Three phase generator differential protection is Four independent stages are available for each phase
provided to detect stator phase faults.This can be set overcurrent element.Each stage may be selected as
as either a percentage bias scheme with a dual slope non-directional or directional (forward/reverse).All
characteristic or as a high impedance scheme.When stages have definite time (DT) delayed characteristics,
high impedance is used, additional stabilising two of the stages may also be independently set to
resistance and metrosil will be required. one of nine inverse definite minimum time (IDMT)
curves (IEC and IEEE).
> Interturn (split phase) differential (P343/4 only) The IDMT stages have a programmable reset timer for
grading with electromechanical relays and to reduce
On generators with multi-turn coils and two or more clearance times where intermittent faults occur.
windings per phase, such as hydrogenerators, The phase fault directional elements are internally
interturn (split phase) differential may be used to polarised by quadrature phase-phase voltages, and
detect turn to turn faults. will make a correct directional decision down to 0.5V
(Vn = 110/120V) or 2.0V (Vn = 380/440V).A
The element operates as a definite time overcurrent synchronous polarising signal is maintained for 3.2s
function with independant current setting per phase.It after voltage collapse to ensure that the instantaneous
should be noted that when using this function the and time delayed overcurrent elements operate
generator differential protection is not available. correctly for close-up three phase faults.
> Interturn (residual overvoltage) > Standard ground fault
On generators with multi-turn or single turn coils The standard ground fault element operates from an
interturn protection can be provided by measuring the ground fault input connection to measure the fault
residual voltage across the 3 phase windings. current in the ground path of the generator.Two
To prevent operation for external faults a negative independent stages are available for each phase
phase sequence apparent power and a directional overcurrent.Both stages have definite time (DT)
negative phase sequence overcurrent element can be delayed characteristics, the first stage may also be
used to interlock the residual overvoltage element in independently set to one of nine inverse definite
PSL. minimum time (IDMT) curves IEC and IEEE).
> 100% stator ground fault 3rd harmonic method > Sensitive ground fault
(P343/4 only)
A core balance CT should be used to drive the
Third harmonic neutral undervoltage protection covers sensitive ground fault function.The directionality is
the final 15% of the stator winding and, in conjunction provided by the residual voltage.
with the other ground fault elements, provides 100%
ground fault protection for the stator.This is supervised > Wattmetric
by a three phase undervoltage element.Additional
supervision using three phase active, reactive and The sensitive ground fault protection is also suitable for
apparent power can be enabled if required.A third Petersen Coil grounded systems by enabling a
harmonic neutral over voltage protection is also wattmetric element.This form of protection uses the
provided for applications where the measurement is sensitive ground fault protection directional
available at the terminal end of the generator.The characteristic, but with a directional residual power
blocking features of the under voltage element are not threshold providing an additional constraint on
required for this application. operation.
> Restricted ground fault
The restricted ground fault protection may be
configured as either high impedance or low impedance
biased differential.When high impedance is used,
additional stabilising resistance and a metrosil will be
required.
MiCOM P343/4 : 100% stator earth fault
and pole slipping protection
for large machines
4>5
> Voltage dependent overcurrent/underimpedance > Power protection
In order to provide backup protection for phase faults, The power protection element provides two stages
an element is included which can be set as either which may be independently configured to operate as
voltage controlled overcurrent, voltage restrained reverse power (RP), over power (OP) or low forward
overcurrent or underimpedance.If selected as voltage power (LFP) protection.The direction of the power
controlled or voltage restrained overcurrent, the timing measured by the protection can be reversed by
characteristic can be set as either definite time or selecting the operating mode, generating/motoring.The
IDMT.If selected as underimpedance, a 2 stage three power protection can be used to provide simple
phase non-directional underimpedance element is overload protection (OP), protection against motoring
provided. (RP, generating mode), CB interlocking to prevent
overspeeding during machine shutdown (LFP,
> Neutral displacement/residual overvoltage generating mode) and/or loss of load protection (LFP,
motoring mode).In addition to the standard 3 phase
Residual overvoltage protection is available for power protection, (minimum setting 0.5% Pn) a
detecting ground faults where there is an isolated or sensitive single phase power protection element can be
high impedance ground.The residual voltage can be used, (minimum setting 0.5% Pn) which uses the
measured from a broken delta VT, from the secondary sensitive ground fault current input.
winding of a distribution transformer ground at the
generator neutral, or can be calculated from the three > Loss of field
phase to neutral voltage measurements.Each stage
can be set with a definite time delay or an inverse time To detect failure of the machine excitation a two stage
delay characteristic. offset mho impedance element is provided.This allows
The P342/3/4/5 have 2 measured and 2 calculated a small instantaneous characteristic to be used to
stages of residual overvoltage protection.The P344 has provide fast tripping for loss of excitation at high power
an additional neutral voltage input and so has an outputs, where system stability could be affected.The
additional 2 stages of measured residual overvoltage second stage can be set with a larger time delayed
protection. characteristic to provide stable, secure tripping under
low power conditions.Integrating timers are provided to
> Under/overvoltage enable the impedance characteristic to provide time
delayed pole slipping protection.A power factor alarm
Under/overvoltage protection may be configured to element is also available to offer more sensitive
operate from either phase-phase or phase-neutral protection for unusual operating conditions, for example
voltage elements.Two independent stages with definite a lightly loaded unit operating as an induction
time elements are available.The first stage can also be generator.
configured to an inverse characteristic.
> Negative phase sequence thermal
> Under/overfrequency
To protect against unbalanced stator currents caused
Two independent stages of overfrequency and four of by external faults or unbalanced loading, two stages of
under frequency are provided.Each stage functions as negative sequence protection are provided.These
a definite time element. comprise a definite time alarm stage and a trip stage
that operates with a thermal characteristic.
> Turbine abnormal frequency
> Negative phase sequence overcurrent
Turbine abnormal frequency protection is included to
protect the turbine blade from potential damage due to Four definite time negative phase sequence overcurrent
prolonged under/over frequency operation of stages are included.Each stage may be selected as
generators.Up to six frequency bands can be non-directional or directional (forward/reverse) and can
programmed, each having an integrating timer to operate for remote phase-phase and phase-ground
record the time spent within the band.The time in each faults even with delta-star transformers present.
band is stored in battery backed memory so that loss of
auxiliary supply to the relay does not lead to a loss of
the recorded time.When the time within a band has
reached the user set limit, an alarm can be raised to
initiate investigation and maintenance.
> Negative phase sequence overvoltage > Resistance temperature detectors (RTDs)
One definite time stage of negative phase sequence In order to monitor temperature accurately, an option
overvoltage protection is provided.Negative phase allowing measurement of temperatures using up to 10
sequence overvoltage protection can be used for the platinum RTDs is available.This provides an
detection of voltage unbalance which will quickly lead instantaneous alarm and time delayed trip output for
to overheating and damage of generators. each RTD.
> Overfluxing > Thermal overload
To protect the generator, or connected transformer, To monitor the thermal state of a generator, a thermal
against overexcitation a five stage V/Hz element is replica protection is provided.The thermal element has
provided.The first stage is a definite time alarm, the a trip and an alarm stage.Positive and negative
second stage can be used to provide an sequence currents are taken into account so that any
inverse/definite time trip characteristic and stages 3/4/5 unbalance condition can be detected and any abnormal
are definite time. heating of the rotor can be avoided.There are separate
time constants for heating and cooling and in the event
> Unintentional energisation at standstill of a loss of auxiliary supply the thermal state is stored
(P343/4 only) in non-volatile memory.
If the machine circuit breaker is closed accidentally, > Blocked overcurrent logic
when the machine is not running, very high current will
result.A voltage supervised overcurrent scheme is Each stage of overcurrent and ground fault protection
available to protect against this condition.When the can be blocked by an optically isolated input.This
machine voltage is low, that is, the machine is not enables the overcurrent and ground fault protection to
running, an instantaneous overcurrent element is be integrated into a blocked overcurrent busbar
enabled.Timers ensure that the element will be stable protection scheme.
for normal voltage dips that could occur for system
faults or machine reconnection. > Analog (Current Loop) Inputs and Outputs
(CLIO)
> Pole slipping (P343/4 only)
Four analog (or current loop) inputs are provided for
The pole slipping protection uses the variation in transducers with ranges of 0-1mA, 0-10mA, 0-20mA or
"apparent" impedance as seen at the generator's 4-20mA.The analog inputs can be used for various
terminals to detect pole slipping.If the measured transducers such as vibration monitors, tachometers
impedance crosses the two halves of the lens and pressure transducers.Associated with each input
characteristic and spends longer than a specified time there are two time delayed protection stages, one for
in each half a pole slip is counted.Two zones are alarm and one for trip.Each stage can be set for 'Over'
created by a reactance line which is used to or 'Under' operation.
distinguish whether the impedance centre of the pole Four analog (or current loop) outputs are provided with
slip is located in the power system or in the generator. ranges of 0-1mA, 0-10mA, 0-20mA or 4-20mA which
Separate counters are used to count pole slips in the 2 can alleviate the need for separate transducers.These
zones.A setting is also provided to determine whether may be used to feed standard moving coil ammeters
the protection operates in a generating mode, motoring for analog indication of certain measured quantities or
mode or both. into a SCADA using an existing analog RTU.
Figure 2
PSL Editor (MiCOM
6>7
SUPERVISORY FUNCTIONS > Circuit breaker condition monitoring
The circuit breaker conditionmonitoring features
include:
> Circuit breaker failure protection (cid:127) monitoring the number of breaker trip operations
(cid:127) recording the sum of the broken current quantity
Two stage circuit breaker failure protection may be ∑Ix, 1.0 ≤ x ≤ 2.0
used for tripping upstream circuit breakers and/or the (cid:127) monitoring the breaker operating time
local secondary trip coil.The circuit breaker failure
(cid:127) monitoring the fault frequency counter
logic may also be initiated externally from other
protection devices if required.The P343/4 CB fail logic
can be set to use current measurement from any of
CONTROL
the 2 sets of 3 phase current inputs.Typically CB fail
protection uses the CTs on the busbar side of the
generator. > Programmable scheme logic
> Voltage transformer supervision Programmable scheme logic allows the user to
customise the protection and control functions.It is
Voltage transformer supervision (VTS) is provided to also used to programme the functionality of the
detect loss of one, two or three VT signals, providing optically isolated inputs, relay outputs and LED
indication and inhibition of voltage dependent indications.The programmable scheme logic
protection elements.An optically isolated input may comprises gate logic and general purpose timers.The
also be configured to initiate the voltage transformer gate logic includes OR, AND and majority gate
supervision alarm and blocking when used with functions, with the ability to invert the inputs and
miniature circuit breakers (MCBs) or other external outputs, and provide feedback.The system is
forms of voltage transformer supervision. optimised to evaluate changes to the scheme logic
signals and thus minimise any delays in logic
> Current transformer supervision execution.The programmable scheme logic may be
configured using the graphical MiCOM S1 PC based
Current transformer supervision (CTS) is provided to support software, as illustrated in Figure 2.The
detect loss of phase CT signals and inhibit the required logic is drawn as shown and is then
operation of current dependent protection elements. downloaded directly into the relay.The logic may also
CTS is provided for both sets of 3 phase CTs in the be uploaded from the relay and then modified using
P343/4 relays. MiCOM S1 support software.
> Independent protection settings groups
PLANT SUPERVISION
The settings are divided into two categories;protection
> Trip circuit monitoring settings and control and support settings.Four setting
groups are provided for the protection settings to allow
Monitoring of the trip circuit in both breaker open and for different operating conditions and adaptive relaying.
closed states can be realised using the programmable
scheme logic. > Control inputs
> Circuit breaker state monitoring The ON/OFF status of 32 control inputs can be
changed manually or remotely via the communications
An alarm will be generated if there is a discrepancy to provide user defined control functions.
between the open and closed contacts of the circuit
breaker.
Comprehensive Post-fault analysis
and communication options
INFORMATION INTERFACES
AREVA TRACK RECORD -
GENERATOR PROTECTION
Information exchange is done via the local control
>> LGPG: First numerical generator protection relay.
panel, the front PC interface, the main rear
First released in1994.Over 1500 devices installed.
communications interface (COMM1/RP1) or an
optional second rear interface (COMM2/RP2). >> MX3IPG1A:Numerical generator protection relay.
First released in1997.Over 500 devices installed
>> 34x:Numerical generator protection relays designed for all generator
> Local communication applications.First released in1999.Over 2000 devices installed.
The front EIA(RS)232 Courier communication port has
been designed for use with the MiCOM S1 software
and is primarily for configuring the relay settings and
programmable scheme logic. It is also used to locally
extract event, fault and disturbance record information
and can be used as a commissioning tool by viewing
all relay measurements simultaneously.
P
E
> Rear communication N-IT
O
SI
VI
The main rear communications interface supports the NO
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AUTOMiCO
AREVA T&D Worldwide Contact Centre: Our policy is one of continuous development.Accordingly the
http://www.areva-td.com/contactcentre/ design of our products may change at any time.Whilst every
effort is made to produce up to date literature, this brochure
Tel.: +44 (0) 1785 250 070 should only be regarded as a guide and is intended for
information purposes only.Its contents do not constitute an offer
for sale or advise on the application of any product referred to in
www.areva-td.com it.We cannot be held responsible for any reliance on any
decisions taken on its contents without specific advice.
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