2MiCOM P921, P922 and P923Voltage and frequency relays

IntroductionPart of the new MiCOM range, theP921, P922 and P923 relaysprovide reliable and highperformance voltage and frequencyprotection.

Their versatility of application andthe association of protectionfunctions with automation, controland measurement functions, as wellas maintenance reduction, providean optimal and innovative solution.

ApplicationTwo voltage ranges are availableto cover the large variety of controlapplications: reference voltagelevels supported by MiCOM P921,P922 and P923 relays from 57V to 480V.

Because of the 3 independentphase overvoltage and phaseundervoltage thresholds, MiCOMP921, P922 and P923 relays areable to provide effective voltageprotection: a typical applicationmight be the protection of motorsand generators. The configurabledetection logic (AND, OR) can alsoindicate the absence of voltage,when the undervoltage protection is used.

The 3 zero-sequence overvoltagethresholds can be applied :

to detect earth faults at the neutral point of generators, withMiCOM P921, P922 and P923relays being insensitive to the3rd harmonic

to detect earth faults for neutralelectrical systems which are veryimpedant or isolated, whilstavoiding the expensive use andinstallation of core balance CTs.

The negative sequence overvoltageprotection provided by the MiCOMP922 and P923 relays is designedto detect unbalanced conditions: itcould therefore be used for motorstarters, in which any unbalancewill lead to overheating anddamage.

The MiCOM P922 and P923relays integrate 6 frequencythresholds which are used forautomated load shedding/loadrestoration.

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Models availableMiCOM P921: voltage protectionrelays, 2 logic inputs, 4 outputs.

MiCOM P922: voltage andfrequency protection relays, eventand fault records, disturbancerecorder, 5 logic inputs, 8 outputcontacts.

A G version (CORTEC code option)is available to meet thespecifications of EDF GTE 2666,types 1 and 2.

MICOM P923 : Voltage andfrequency protection relay (Plus therate of change of frequencyelement df/dt), event and faultrecords, disturbance recorder,5logic inputs, 8 output contacts.

5 optoinputs

RS485Communication

Setting software

3 phases VTs

Watchdog

7 auxiliaryoutputs

Trip output

P92330 86

47

WD

RS232 RS485

27 5959N 27D

81U 81OLoadingresistor

81R

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In addition, the MiCOM P923relays provide 6 thresholds ofinstantaneous rate of change offrequency (df/dt) or averagemeasurements over a settable timeinterval.

These elements are suitable forsevere disturbances accelerate theload shedding when this operation,in small step, may not be sufficientto bring the system back to normaloperating condition.

In order to adapt the protectionscheme to each application,programmable logic equations areavailable and allow thecombination of MiCOM P921,P922 and P923 internal protectionfunctions of relays with externalsignals from other protectiondevices on the system. Thisflexibility reduces both externalwiring and the use of auxiliaryrelays.

The MiCOM P921, P922 andP923 relays primarily providefast and accurate protectionfor use in numerousapplications. In addition, theyoffer the following benefits:

protection, control,measurements and recordsin a single case, therebyreducing the number ofdevices and the total cost ofinstallation

clear indication of eventswhich have taken place,via explicit messages andprogrammable LEDs on thefront panel, increasingoperational efficiency

simple integration intocontrol systems through theuse of a large number ofavailable standardcommunication protocols,with no additional cost

Advantages of MiCOM P921, MiCOM P922 and MiCOM P923 relays

standardisation of cases,identical to the MiCOMP120 series relays.

diagnostic supportfollowing a fault, throughthe use of event recordsand disturbance records

maximum security providedby periodic self-tests

increased flexibility throughlogic inputs, outputcontacts, LEDs andprogrammable logicequations

3 different ways of enteringthe relay settings whilstconstantly aiming atproviding the safety, speedand simplicity required forthis type of operation

possibility of using a"battery" box (MiCOM E1)to set the relay, without theneed to provide anauxiliary supply

powerful and intuitiveMiCOM S1 supportsoftware designed tominimise the need fordocumentation and training

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4Functions available

Functions ANSI Codes MiCOM P921 MiCOM P922 MiCOM P923Version S Version G

ProtectionConfiguration depending on the number and type of voltage transformers X X X XPhase-to-neutral or phase-to-phase voltage protection X X X XPhase undervoltage (AND/OR logic) 27 X X OR Logic XPhase overvoltage (AND/OR logic) 59 X X OR Logic XSettable Hysteresis X XZero-sequence overvoltage 59N X X X XNegative sequence overvoltage 47 X XPositive sequence undervoltage 27D X XUnder/overfrequency 81U/81O X X XRate of change of Frequency 81R XNominal operating frequency: 50 Hz/60 Hz X X X XInhibition of voltage & frequency protection functions XInhibition of timers (instantaneous forcing) XControlProgrammable logic equations X X X XProgrammable logic inputs and outputs 30 X X X XFail-safe operation XBlocking logic X X XUndervoltage Blocking XCircuit breaker control X X X XLatching of output contacts 86 X X X XSetting groups for protection parameters 1 2 2 2Possible prohibition of remote setting XMeasurementsPhase-to-neutral or phase-to-phase voltages with true RMS values X X X XResidual voltage with true RMS value X X X XFrequency X X X XPositive and negative sequence voltages X XRolling and peak values X XLogs and recordsEvent records X X XFault records X X XDisturbance records X X XFrequency Disturbance records XMonitoringMonitoring the position of the circuit breaker X X X XData for circuit breaker maintenance X X XCommunicationsRemote communication (RS485 port) X X X XLocal communication (RS232 port) X X X XUser interfaceBack-lit LCD display X X X XProgrammable LEDs X X X XPassword-protected access (with optional transparent front cover) X X X XCompatible setting software MiCOM S1(Windows) X X X X

5Protection functions

Configuration depending on the VTMiCOM P921, P922 and P923relays can be used in the followingconfigurations: "3 phase-neutral VTs" or

"3 phase-neutral VTs and 1residual VT": The voltage protection elementcan therefore operate either frommeasured phase-to-neutralvoltages, or from phase-to-phasevoltages which have beeninternally calculated by the relay.Zero-sequence overvoltageprotection will always beavailable, the presence of theresidual VT is designed todisplay the true RMS value of theresidual voltage,

"3 phase-phase VTs and 1 residual VT" or "2 phase-phase VTs and 1 residual VT": The voltage protection elementcan only operate from measuredphase-to-phase voltages. If theresidual VT is not connected, thezero-sequence overvoltageprotection will not be available.

The MiCOM P922-G is onlydesigned to operate with the "3 phase-neutral VTs" or "3 phase-phase VTs"configuration.

Voltage protectionFor each function listed below, aninstantaneous signal and a time-delayed signal is available foreach threshold.For time-delayed signals, the firstthreshold of each function ("lowthreshold") offers the choicebetween a definite timer and aninverse timer, to which a reset timercan be assigned. The otherthresholds only have one definitetimer.In the case of the MiCOM P922-G,all thresholds have definite time-delays and the only detection logicis the "OR" logic.

Under/Overvoltage (27/59)Three thresholds are available foreach function: each one can beindependently activated ordeactivated.

If a threshold is activated, it can beconfigured to detect: an overvoltage on the 3

simultaneous phases (logic"AND") or on at least one of thephases (logic "OR") for the"Overvoltage" function

an undervoltage on the 3simultaneous phases (absence ofvoltage with the "AND" logic) oron at least one of the phases(logic "OR") for the"Undervoltage" function

The MiCOM P923 and P923relays provide a programmablehysteresis(drop- out / pick-up ratio) as apercentage of the under voltageand over voltage settings values.

The MiCOM P922 provides asettable under voltage Block ofall the protection and controlelements based on thefrequency.

Zero-sequence overvoltage(59N)Three thresholds are available:each one can be independentlyactivated or deactivated.Depending on the VT configuration,MiCOM P921, P922 and P923relays will operate from the zero-sequence voltage, which iscalculated internally, or from theresidual voltage, which is measureddirectly.

Negative sequenceovervoltage (47) - MiCOM P922 (S version) and P923Two thresholds are available: eachone can be independently activatedor deactivated.This function is based on thenegative-sequence component ofthe voltage, which is calculatedinternally and displayed on thescreen of the front panel: It isdesigned to detect any voltageunbalance condition.

Positive sequenceundervoltage (27D) - MiCOM P922 (S version)and P923Two thresholds are available: Eachone can be independently activatedor deactivated.This function is based on thepositive phase sequencecomponent of the voltage, which iscalculated internally.

Frequency protectionsFrequency protection functions areinhibited from a certain level of themeasured secondary voltage(adjustable level on G version).

Under/Overfrequency(81U/81O) - MiCOM P922and P923Six thresholds are available: Eachone can be configured to detect anunder or overfrequency within therange [fn - 10Hz, fn + 10Hz],where fn is the nominal frequencyselected (50Hz or 60Hz).

A definite timer is assigned to eachthreshold.

Rate of Change of Frequency(81R)- MiCOM P923Six threshold are available: Eachcan be configured independentlywithin the range[-10 Hz/s, +10 Hz/s]. These functions are based on thecalculation of the instantaneousrate of change of frequency over asettable integration time (number ofcycles).

Automation

Earth fault(V0>)

Trip&

Timer

Manualclose

(tAUX1)

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Programmable logic equations Two programmable logic equations(AND) are available with MiCOM P921 and P922 relays. Four programmable logic equations(AND) are available with MiCOM P923.A pick-up timer and a drop-offtimer can be assigned to eachequation.These equations are not defined ingraphic form, they can thus becalculated directly from the frontpanel, thereby avoiding the needfor dedicated software.

Inputs/Outputs/Programmable LEDs

All logic inputs, output contacts(excluding the RL0 changeoveroutput contact, dedicated to the"relay failed" function) and the 4LEDs of the MiCOM P921, P922and P923 relays can beprogrammed. This affects in particular all logicsignals (instantaneous, time-delayed) in the relays which can becombined on the different outputcontacts and LEDs.

Blocking logicWhen MiCOM relays are used inelectrical systems, the managementof the different protection modulesmust take surrounding devices intoconsideration. MiCOM P921, P922and P923 relays supplyconfigurable logic inputs, which,when active, can "freeze" theassociated protection timers andfault is still present if the after drop-off can re-impose the initial value.

Output contact latching (86)Each output contact can beprogrammed to be latched once thefault has cleared: The latchedcontacts can be reset either directlyon the front panel of the relay,locally (RS232 port) or remotely(RS485 port).

Setting groups for protectionfunctionsThe MiCOM P922 and P923 relayshave two independent settinggroups, which are used to adaptthe protection functions to differentoperating conditions. The twogroups can be switched byactivating a dedicated logic input,or by the operator via the frontpanel, or locally (RS232 port) orremotely (RS485 port). Typically,these two setting groups can beused to switch from GTE type 1.4 to GTE type 1.1 for the MiCOM P922 G version.

The switch from one setting groupto another will only take effect if noprotection or automation functionsare running, to prevent unwantedtripping.

MeasurementsIn accordance with theconfiguration of the VTs connectedto MiCOM P921, P922 and P923relays, the following values will bedisplayed as true RMS values onthe back-lit screen:

phase-to-neutral voltages Ua, Ub, Uc

phase-to-phase voltages Uab,Ubc, Uca

residual voltage Vo

frequency.

In addition, the MiCOM P922 (S version) and P923 relayscalculate the following valuesinternally:

positive sequence voltage

negative sequence voltage

peak values of phase-to-neutralor phase-to-phase voltages

rolling values of phase-to-neutralor phase-to-phase voltages

All measurements are availablelocally or remotely.

Logs and recordsAll event, fault and disturbancerecords are time-stamped to 1ms bythe internal real time clock.

In the event of a loss of auxiliarypower, a lithium battery is used tosave the records, the date and thetime. Checked at regular intervals,the battery can be easily accessedfrom the front panel if it has to bereplaced.

Event recordsAny change of state of logic inputs,output contacts or protectionfunctions will be recorded in thenon-volatile memory of the MiCOM P922 and P923 relays,with a maximum of 75 events.When the memory is full, the oldestevents will be deleted, which willincrease the storage capacity formore recent events.

Each event can either be displayedlocally using the MiCOM S1support software (RS232 port) orremotely (RS485 port).

Fault recordsThe MiCOM P922 and P923 relayscan store the last 5 faults that haveoccurred in non-volatile memory.

Each record provides the followinginformation:

date and time of fault

origin of fault (undervoltage, etc.)

faulted phase(s)

magnitude of the quantity whichlead to the fault

magnitude of phase-to-neutral orphase-to-phase voltages

magnitude of the zero-sequencevoltage (if available)

All this information can be restoredlocally, using the MiCOM S1setting software (RS232 port), orremotely (RS485 port).

Disturbance recordsFive disturbance records, eachlasting 2.5 seconds, can be storedin non-volatile memory by MiCOMP922 and P923 relays. Thesampling frequency is fixed at 32samples per cycle. The mechanismthat triggers the recording can beconfigured: Instantaneous signals,time-delayed signals, or activationof a dedicated logic input.

The various recordings can berestored locally (RS232 port) or fedback remotely (RS485 port).

Frequency disturbancerecordsOne frequency disturbance record,lasting 20 secs can be stored innon-volatile memory by the MiCOMP923 relay. The sampling frequencyis fixed at 1 sample per cycle. Themechanism that triggers therecording can be configured:instantaneous or time delayedtripping, activation of a dedicatedlogic input or time delayed logicequation signal.

The various recordings can berestored locally (RS232 port) or fedback remotely (RS485 port).

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Disturbance Record Analysis

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Fully WINDOWS compatible(98, NT), the MiCOM S1 settingsoftware has been designed so thatall relay settings can be preparedin the office ("off-line" mode) andthe configuration file created canthen be loaded on-site.

The different information stored byeach MiCOM relay (measurements,event records, disturbance records,parameters, etc.) can also beretrieved by the software (storageon PC, printout of various files, etc.)and used on-site or processed at alater date.

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Circuit breakermonitoring and control

Monitoring the position ofthe circuit breakerThe use of logic inputs andprogrammable LEDs enables theposition of the circuit breaker to bedisplayed on the front panel.

Circuit breaker controlWith MiCOM P921, P922 andP923 relays, the circuit breaker canbe controlled locally via logicinputs (AUX1 and AUX2), withlocal or remote communication: theopening and closing commandswill therefore activate theprogrammed output contacts.

Circuit breaker maintenance -MiCOM P922 and P923In addition to protecting andcontrolling the electrical network,the MiCOM P922-P923 relays willprovide preventive and curativemaintenance of the circuit breakers.The maintenance programs can beadapted in accordance with thedata supplied by the relay.

The MiCOM P922 and P923relays control the opening andclosing time of the circuit breaker,and monitor the number ofoperations carried out. An alarm istriggered as soon as the maximumopening or closing time, or themaximum permitted number ofoperations is exceeded.

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Hysteresis: 50mHz

I 5 Hz/T for df/dt with IT :Integration time, settable from 1 to 200

Timers:

2% or 10ms for DT

5% or 40ms for IDMT

t = TMSUUThreshold

1

11

Technical specifications

Voltage inputs (Vn)4 voltage inputs

2 ranges available (RMS phase-phase voltage): 57-130V or 220-480V

Primary voltage:

from 0.1 to 100kV, steps of0.01kV, range 57-130V

from 220 to 480V, steps of 10V,range 220-480V

Secondary voltage:

from 57 to 130V, steps of 0.1V,range 57-130V

from 220 to 480V, steps of 10V,range 220-480V

Thermal withstand andvoltage input burdenRange 57-130V:260V continuous300V for 10sburden: < 0.25 VA

Range 220-480V:960V continuous1300V for 10sburden: < 0.36 VA

FrequencyNominal frequency 50/60 Hz

Operating range 40/70 Hz

Auxiliary supply VauxThree ranges available

24 - 60 Vdc

48 -150 Vdc

130 - 250 Vdc / 100 - 250 Vac, 50/60 Hz

Consumption:

DC: 3W (standby)+ 0.25W per energised outputrelay

AC: 6 VA (standby)+ 0.5VA per energised output relay

Logic inputsNumber of logic inputs:2 (P921), 5 (P922 and P923)

Configuration (P922-G) : active onlow or high level or pulse for theinput dedicated to the change ofsetting group, active on low or highlevel for the other inputs

Polarisation: direct voltage withinthe same range as the auxiliaryvoltage

Response time: < 2ms

Burden: 10000 operations

Communication ports

Rear communication portConnection: multidrop (32 units)Type of cable: twisted shielded pairLength of cable: 1000m max.Connectors: screw terminalsLink: RS485Isolation: SELV

Front communication portConnection: peer to peerCable type: multi-coreCable lenght: 15m max.Connectors: RS232 DTE, 9-pin,femaleLink: RS232Isolation: ELV

Backup batterySaves the date and time of event,fault and disturbance records aswell as frequency disturbancerecord (P923 only) in the event ofan auxiliary power failure

Battery type: lithium, 1/2 AA,3.6V, 850mAh, 10-year guarantee

CaseThe characteristics of the case areshown in figure 11 (page13).

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Standard tests

Environment Temperature IEC 60255-6

Storage-25C to +70C

Operation-25C to +55C

HumidityIEC 60068-2-3 56 days at 93%

RH and 40C Enclosure protection

IEC 60529 IP 52, IK 07 Vibrations IEC 60255-21-1 Response and endurance,

class 2 Shock and bump

IEC 60255-21-11 class 1 Seismic withstand

IEC 60255-21-3, class 1

EMC compliance

89/336/EEC

Conformity to EEC EMCdirectives can be found in thetechnical construction file.

The following genericstandards have been used as abasis for this conformity:

EN 50081-2: 1994EN 50082-2: 1995

Product safety

73/23/EEC

Conformity to EEC low voltagedirectives.

Conformity is based on thefollowing generic safetystandards:

EN61010-1: 1993/A2: 1995EN60950: 1992/A11: 1997

Additional information Technical guide:

ref. TG1. 1530

MiCOM S1 user manual:ref. R8610

MIDOS parts catalogue:ref. R7012

Standards Dielectric withstand

IEC 60255-52 kV common mode1 kV differential mode

Impulse voltage IEC 60255-55 kV common mode1 kV differential mode

Insulation resistance IEC 60255-5

> 100 MW High frequency disturbance

IEC 61000-4-12.5 kV common mode, class 31 kV differential mode, class 3

Fast transient disturbance IEC 61000-4-4ANSI C37.90.1

Electrostatic dischargeIEC 61000-4-28 kV, class 4

Radiation immunityANSI C37.90.235 V/mIEC 61000-4-3 10 V/m

22625,1

Side view, flush mounting

151,2 max.

7851.8

10,5

158168

23,6

Alldimensionsin mm.

Panel cut-out flush mountingfixing details

Relay weight (case + active part) 2,1 kg

99 4 holes 4,4 (M4 screw)

103 (20 TE)

.

C

MiCOM P921

VA = 24.50 V

177

Face view

4 holes 3,4

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Outline descriptionNumerical protection for thedetection of voltage (P921, P922and P923) and frequency (P922and P923) variations in a 4U draw out metal case.

A G version which meets EDF GTE2666 specifications is available forthe P922 model.

The following functions areavailable in MiCOM P921, P922and P923 relays:

3 independent phaseovervoltage thresholds(instantaneous and time-delayed- ANSI 59 code)

3 independent phaseundervoltage thresholds(instantaneous and time-delayed- ANSI 27 code)

3 independent zero-sequenceovervoltage thresholds(instantaneous and time-delayed- ANSI 59N code)

2 programmable logic equations(P921 - P922)

Programmable I/O

Relay latching (ANSI 86 code)

Display of true RMS values

An RS485 rear port compatiblewith one of the followingprotocols: MODBUS, Courier,IEC 60870-3-105

The MiCOM P922 (S version) andMiCOM P923 relays offer thefollowing additional functions:

2 independent negativesequence phase overvoltagethresholds (instantaneous andtime-delayed - ANSI 47 code)

2 independent positive sequencephase undervoltage thresholds(instantaneous and time-delayed- ANSI 27D code)

Settable Hysteresis thresholds forUndervoltage and Overvoltagefunctions.

The MiCOM P922 relay, G version, is designed to:

instantaneously force tripping totake account of make on powerpresent (MPP)

program output contacts 1 and 2for fail-safe operation

provide the possibility to prohibitall remote configurations

MiCOM P922 (S and G versions)and MiCOM P923 relays,therefore integrate: 6 independent

over/underfrequency thresholds(instantaneous and time-delayed- ANSI 81U/81O codes)

Records of the last 75 events,time-stamped to 1 ms

Data records relating to the last5 faults

Disturbance recorder withstorage of 5 records, eachlasting 2.5 seconds, 32 samplesper cycle

The MiCOM P923 relay offers thefollowing additional functions:

6 independent rate of change offrequency thresholds - ANSI 81R codes

1 adjustableundervoltage Blocking threshold

4 programmable logic equations

The user interface is common toMiCOM P921, P922 and P923relays and includes the followingelements:

A 32-character alphanumericback-lit LCD display

An RS232 front port compatiblewith application software andPC setting software

Programmable LEDs withcustomised labelling

13

14

Relay type

User interface language options (see note 1)

Voltage relayVoltage/frequency relay (only possibility for G application)Voltage/frequency with (df/dt)

123

Franais (choix unique pour application G)EnglishSpanishGermanItalianRussianPolishPortugueseDutchCzechHungarian

012345678AB

Voltage inputs

57 130 V220 480 V

AB

Application

Auxiliary voltage supply

StandardEDF / GTE2666 (types 1&2)

SG

24 60Vdc 48 150Vdc 130 250Vdc/100 250Vac 50/60 Hz

AFM

Communications protocol options

Modbus (only possibility for G application) K-BUS / CourierCEI 60870-5-103

123

Note 1 : please consult us for language availability.

P92MiCOM 0 1

Informations required with order: