A Lenticular Characteristic Adapted ToVery High Voltage Networks

Fields of applicationPXLP 3000 is a static full schemedistance protection capable ofdetecting all types of faults. It ismainly designed for fast and selectiveprotection of high and very highvoltage networks interconnected ornot, with solidly earthed neutral orusing impedance earthing (reactive) atlow value. PXLP 3000 is particularlysuitable for networks in which faultcurrents may be well below the loadcurrent and for the supervision of longlines because of its lenticular orcircular characteristic which iscapable of being offcentered.

Main characteristics• Underimpedance starting• Circular or lenticular characteristicsselected by internal switch.• 4 forward zones, 1 reverse zone.• 4 tripping steps.• Reactance type zone measurementfor eliminating the influence of faultresistance and load current.• Independent measurement systemfor each loop being monitored.• Electronic voltage memory slavedonto the network frequency permittingdirectional operation even in the eventof sub-station close-up three-phasefaults.• Fuse failure detection.• Instantaneous tripping in the eventof closing onto fault.• Locking device in event of power

swing detection.• Programming by switches for thefollowing signalling schemes :- step acceleration,- permissive overreach,- blocking,- direct inter-tripping.• Programming of single phase orthree-phase tripping modes for varioussteps.• Built-in single phase-three-phaseauto-recloser.

OperationThe three voltages and three currentsfrom the measurement reducers feedtransformers ensuring galvanicinsulation and reducing levels tovalues compatible with the electronics.In bloc 1, the signal from thetransformer are added to generatezero sequence quantities of Vo, Io,Ko.Bloc 2 includes six underimpedancerelays and their settings. These relaysserve to start the protection.Bloc 3 includes the voltage memorycircuit.Bloc 4 ensures band pass filtering ofinput quantities, thus eliminating allsignals which are harmful formeasurement : aperiodic component,line oscillation, CVT transients,harmonics...Bloc 5 carries out zone setting.Bloc 6 makes measurements.Bloc 7 receives measurement data,

processes it, dialogues with the steptime delays and generates outputsignals (trippings and indications).Bloc 8 represents the protectionpower supply DC-DC converter.Bloc 9 includes step time delays.Bloc 10 represents optical indications.Bloc 11 includes indication andtripping contacts.Bloc 12 receives data from the outside(fuse failure, line closing, ...).Bloc 13 includes an optional powerswing detection circuit.

Proven measurement principles

StartingFor each of the six starting elements,the protection generates twodifferential voltages whose phase shiftis measured. The impedance pointfalls within starting when themeasured phase shift is greater than90° for a circular characteristic or100 to 130° for a lenticularcharacteristic.

Distance measurementA differential voltage is generated foreach of the loops (six per zone). In thesame way as for starting, the phaseshift of this voltage is measured whithrespect to a current image voltage.The impedance point is within thezone in question when the phase shiftis greater than 90°.For earth faults, distance measurementin the first zone is carried out whenthe voltage drop in the fault resistanceis zero (zero instantaneous residualcurrent), rendering this measurementparticularly insensitive to faultresistance. It is also insensitive tofrequencies, aperiodics and loads.

Direction measurementwithout dead zone• Phase-to-phase faultsThe voltage representing the directionof fault current flow is compared witha stored positive-sequence voltage(electronic memory voltage). Thuseven in the event of a three-phasefault witout voltage, correct directionalinformation is preserved.• Phase-to-earth faultsThe zero sequence power flowdirection is measured. To avoid anyincertainties when the fault is far offand the sources are powerful, thezero sequence voltage iscompensated for. This is equivalent tobringing the relay closer to the faultpoint.

Fault on secondary sideof a voltage reducerA logic checking the presence ofresidual voltage and the absence ofresidual current detects the blowing ofone of the fuses across the secondaryof the VT or the breaking of one of theconnection circuits. This detectioninstantly blocks the protection and

3I

3U

Operation block diagram

12

10

13

1ΣU, ΣI

(Vo, Io, Ko)

3V

memoryD

11

2 4

Logical

5 7

9 8CC

CC

6

triggers an alarm by contact after atime delay has elapsed. Blocking canalso be controlled by an externaldevice (protection of reducers byminiature circuit breaker).

Closing onto faultsIn the event of a circuit breakerclosing on a faulty line, the protectiontrips on a starting criterion.

AlarmsOn the front panel of the protection,there are indicator lamps whichindicate the faulty phase or phasesand the tripping zone. The indicationis stored (bistables) even in the eventof auxiliary supply loss. Manypolarity-free contacts are provided topermit remote signalling.

TrippingIn its basic version, the protectionincludes six tripping contacts (two perphase) providing direct control of thecircuit-breaker coils. To prevent anydeterioration, the contacts are held aslong as the current conducted throughthem is greater than 0.2 A.

Complementary modules• Power swing detectionThe module measures the speed ofvariation of the impedance pointbetween two circular or lenticularcharacteristics. After initial detection,the protection is blocked for onesecond and blocking is rearmed aftereach further passage through thepower swing band. Internal selectorsare used for choosing the zone forwhich blocking is effective. In theevent of a simultaneous single phasefault, the protection is unlockedimmediatly.• Auto-recloserThe protection can incorporate asingle phase-three-phase auto-reclosermodule. It includes a 6-positionselector for choosing the desiredoperating mode.

Technical characteristics

Input circuits

Rated voltage Un 100 to 130 V(or 200 to 260 V for non-standard model)

Constantly permissible voltage 2 UnBurden 0.1 VAFrequency 50 or 60 HzRated current In 1 or 5 AConstant overload current 4 InOverload current for 10 s 30 InOverload current for 1 s 100 InBurden measured across rack terminal 0.1 VA (1 A) ; 0.5 VA (5 A)

Auxiliary supply

Inaudible DC/DC converter 48,110, 125, 220, 250 V DCTolerance -20%, +20%

except for 250 V DC : -20%, +10%Standby state consumption 30 WFault state consumption 55 W

Settings

Forward supervision limit : X4 X4 = 10 x Fn ohms/phaseN4 + 1 In

N4 adjustable from 0 to 99 bythumbwheels switches

Table of X4 limits (in ohms/phase)

In Fn 50 Hz 60 Hz

1 A 5 to 500 6 to 6005 A 1 to 100 1.2 to 120

Reverse supervision limit : X5 X5 = K5 x X4 with K5 = 1, 1/2, 1/4, 1/8Characteristics form a a = 0.47 ; 0.58 ; 0.7 ; 0.84 ; 1b b

First zone limit : X1 X1 = a1 x 0.4 x Fn ohms/phaseN1 +1 In

a1 = 1, 5, 10, 50 thumbwheel switchesN1 = 0 to 99

Second zone limit : X2(same equation as for X2 with index 2) Table of X1 limits

(in steps equal or less than 5%)

In Fn 50 Hz 60 Hz

Third zone limit : X3 1 A 0.2 to 100 0.24 to 120(same equation as for X1 with index 3) 5 A 0.04 to 20 0.048 to 24The settings for all 3 zones are independent

Earth coefficient : Ko = Xo - Xd Setting from 0 to 1.5 in steps of 0.13 Xd (thumbwheel switch)

Reference impedance characteristic angle F = 50 Hz : 45° to 86° in 16 steps(line angle) : ϕ F = 60 Hz : 50° to 87° (thumbwheel

switch)

X

R

b

aϕ

X4

X5

X

R

First zone forward

X1

X

R

Second zone forward

X2

X

R

Third zone forward

X3

X

R

Fourth zone forwardFifth zone reverse

X5

X4

SettingsTime delays : step 1 T1 0 to 495 ms in steps of 5 ms

step 2 T2 0 to 990 ms in steps of 10 msor 0 to 9.9 s in steps of 0.1 s

step 3 T3 0 to 9.9 s in steps of 0.1 sstep 4 T4 0 to 9.9 s in steps of 0.1 s

Sensitivity : phase current threshold 0.15 InEarth current threshold 0.1 to 1.6 In in steps of 0.1 In or

0.2 to 3.2 In in steps of 0.2 Inor percentage relay (thumbwheel switch)

Directional sensitivity unlimited for all unbalance faultsunlimited for 0.5 s for nearby three-phasefaults (voltage memory)

Power swing detector ∆ X4 with X4 : forward zone value∆ : setting : 0.1 ; 0.2 ; 0.4 ; 1

AccuracyDistance measurements 1st, 2nd and 3rd zone for an SIR from 0.1 to 30 andcurrent from 0.25 to 30 In 5% of set valueStarting 10% of set valueTime delays 2% of set value Operating timeMinimum value : 15 ms, typical value : 25 msAuto-recloserSingle phase cycle 0.1 to 9.9 s in steps of 0.1 sFast three phase cycle 0.05 to 4.95 s in steps of 0.05 sSlow three phase cycle 1 to 99 s in steps of 1 sReclaim time 1 to 99 s in steps of 1 sTripping circuits 2 tripping contacts per phase, self-held for current greater than 0.2 AContacts • Tripping :

Max service voltage 250 VMaking current (0.5 s) 30 APermanent current 5 ABreaking capacity (L/R = 40 ms) 0.75 A at 48 VDC

0.30 A at 125 VDC0.15 A at 220-250 VDC

• Indication :Max service voltage 250 VPermanent current 5 ABreaking capacity (L/R = 40 ms) 0.75 A at 48 VDC

0.30 A at 125 VDC0.15 A at 220-250 VDC

Environment In operation -10° C to +55° CStorage -40° C to +70° CRelative humidity less than 95% without condensationInsulation (International standard IEC 255)Dielectric strength 2 kV, 50 Hz, 1 mnImpulse wave withstand 5 kV, 1.2/50 µs, 0.5 JHigh frequency perturbation 2.5 kV, 1 MHzPresentation Size : one 19’’ rack, 8 UWidth 483 mmHeight 354 mmDepth 304 mmWeight of complete model 25 kg

thumb-wheelswitches

Modular And Compact Technology

VariantsDepending on the number ofindependent measurement elementsand the built-in complementary

modules, the protection is codified asfollows :

Code Zone 2 Zone 3 P/S 2-pole opening onindependent independent

3001

3002 •

3003 •

3004 • •

3005 •

3006 • •

3007 • •

3008 • • •

3009 •

3010 • •

3011 • •

3012 • • •

3013 • •

3014 • • •

3015 • • •

3016 • • • •

Auto-recloser module

Signalling schemesBy means of internal selectors, thefollowing remote action types can beselected :- step acceleration,- permissive overreach,- blocking,- intertripping.

Step accelerationB detects the fault in Zone 1 andsends a signal to A which switches itsmeasurement reach in Zone 2 withoutwaiting for the second step. Thus, afault near B, normally eliminated at T2

by A, will be eliminated at T1.

Permissive overreachA sees the fault in extended Zone 1and sends the signal to B which tripsif it has detected the fault in itsextended Zone 1.

Blocking(2) : B detects the reverse fault andsends a signal to A, inhibiting it fromtripping.(1) : A and B both detect the fault inextended Zone 1 and trip after aslight waiting delay for a possibleblocking order.

A Z1A

Z1B

Z2A

Z2B

B

AZ2AZ1A or

Z2BZ1B or

B

AZ2AZ1A or

Z2BZ1B or

B

(1)

Z4B

Z4A

(2)

A Single StandardizedPresentation

3L 2L 1L

PresentationPXLP 3000 is a modular rangeprotection. It is built in the form of an8 U 19’’ standardized rack, whateverthe model. All these models includethe following basic parts :- transformer unit,- card for low level testing,- starting, zone measurement and timedelay modules,- memory voltage modules,- indicating and tripping modules,- input-output modules.At all stages of manufacture, fromcomponent incoming checking to finalinspection, protection is put through asevere quality control plan designed toensure optimum reliability. Toeliminate faults in the early stage, theprotection undergoes oven debuggingfor a period of 168 hours.

Testing and maintenanceIn the same way as all the modularrange protections, PXLP 3000 can betested at low level by means of a cardinterfacing with the DLF 3000 test set.During testing, all the tripping signalscan be inhibited to prevent anyinadvertent tripping.

DocumentationOn request :- descriptive leaflet : ND 1.6867- commissioning leaflet : MS 1.6867- maintenance leaflet : M 1.6867

Indication card

Simplified diagram of PXLP 3000 connections

brbr

Auxiliary supply

+T2Tripping A2Tripping B2Tripping C2

Starting informationMRDA2DB2DC2

+T2

+T6Phase tripping indication A6Phase tripping indication B6Phase tripping indication C6

DA6DB6DC6

+T6

+T5NA Phase A fault informationNB Phase B fault informationNC Phase C fault information

Tripping information

Tripping information

Single Phase fault information

Single Phase fault information

NANBNCDTMN

+T5

+T1Tripping A1Tripping B1Tripping C1

+T4Zone 1 tripping signalZone 2 tripping signalZone 3 tripping signalZone 5 tripping signal

NA Phase A fault informationNB Phase B fault informationNC Phase C fault information

Z1Z2Z3Z5NANB

A4 tripping indicationB4 tripping indicationC4 tripping indication

Multi-phase fault indicationStarting information

Fuse failure informationAuxiliary supply

failure indication

DA4DB4DC4PYMRFFMSA

Power swing detection indication

W

NCDTMN

+T4

DA1DB1DC1

+T1

+T3Tripping indication Phase A3Tripping indication Phase B3Tripping indication Phase C3

DA3DB3DC3

+T3

Auto-recloser controlMR

Remote protection transmissionMR

Remote tripping transmission Zone 1MR

Monitoring direction inversion inputINV

Choice of three-phase tripping by protectionBDT

HF presence inputPHFReception - Remote protectionCommonRHF

Protection blocking inputVERCB closing input

TPLFuse failure reception inputCommonRFF

N 1

.686

7 B

- 04/

96

Overall dimensions

482.6

466

356 465.1

316

23

(19'')35

4.8

(8 U

)

354.

8 (8

U)

101.

610

1.6

76.2

37.7

450 min.

8 holes M6

101.

610

1.6

76.2

37.7

Information required when ordering• Code 3 0 0 (see table on page 6)• Rated current 1 A 5 A• Rated voltage 100 200

• Frequency 50 Hz 60 Hz• Auxiliary 48 Vcc 110 Vcc 125 Vcc 220 Vcc 250 Vcc

supply

Note : on leaving the works, and unless the above information is given, modelconfiguration will be as follows :• Basic model : 3001• Rated current : 5 A (transformable to 1 A)• Rated voltage : 100/ V• Rated frequency : 50 Hz (transformable to 60 Hz)

130 2603 3

3

3 3

TRA

NSC

OM

P Ed

ition

67

92 0

2 20

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