Maharashtra State Power Generation Co. Ltd. Thermal Thermal Power Power Station, Station, Parli – V Testing Stage - II
Report on Parli Unit No. 4 Modification in Generator Protection Scheme Prepared by : P. A. Amilkanthwar Modifications usingAlstom make Generator Protection Relay Micom Micom P343
Importance Of Generator Protection Scheme Generator is a having vital importance in the generating stations. It is one of the expens expensive ive equipm equipment ents s instal installed led in therma thermall power power plant. plant. Hence it is worth to have reliable and accurate protective system for the generator. Though the protective relays cannot prevent the faults to occur but the correct protection system can definitely avoid or minimize the the seco second ndar ary y dama damage ge to the the gene genera rato torr unde underr faul faultt cond condit itio ion n or runnin running g under under abnorm abnormal al workin working g condi conditio tions ns this includ includes es extern external al faults, working beyond capability, etc.
Previous Generator Protection Scheme Previously ABB Make Static conventional Generator protection Scheme was installed at Parli Unit No. 4 during first commissioning of the unit. During every annual over haul of the unit the protective relays are being being tested tested and and the results results of relay relay testin testing g shows shows the genera generator tor prot protec ectio tion n rela relays ys are loos loosin ing g its its accu accurac racy y and and reli reliab abili ility ty,, it was was observed since few years. Some of the relays getting mal operated hence the reliability of operation was decreased. This might be due to aging. Most of the relays used were basically designed for 110Vdc and by using voltage dropping resistances, those were used with 220 vdc hence internal heating caused damage to the relays. Also the relays were of old technology and the setting ranges were limited. Hence it was difficult to set the relays accurately, according to the generator capabilities. The event logging and disturbance recording was not available with old relays. Hence it was difficult to analyze the fault / events occurred and the tripping analysis was based on imagination only. The on-line healthiness checking was not available with old relays. This was was alwa always ys crea creatin ting g doub doubtt in the the mind mind abou aboutt the the avail availab abili ility ty of protection. Consid Consideri ering ng the above above it was necess necessary ary to change change the genera generator tor protection scheme.
Availability of Suitable Relay in the Market: PAGE 1 OF 58
ALST ALSTOM OM intr introd oduc uced ed protection relay Type P343 •
micr microp opro roce cess ssor or
base based d
inte integr grat ated ed
gene genera rato tor r
Salient Features of the relay P343: Following Protections of generator are covered in the relay 1. Generat Generator or Differe Differentia ntiall Protec Protectio tion: n: - Phase Phase segre segregat gated ed differ different ential ial protec protectio tion n operati operating ng on a biased biased or high high imped impedanc ance e princi principle ple.. Provides high speed, discriminative protection for all fault types. {P343 only} OR Gene Genera rato torr Inte Intertu rturn rn prot protec ecti tion on:: suita suitabl ble e for for use use with with split split phas phase e generator and CBCT with facility of DT function. 2. Phas Phase e faul faultt over over curre current nt prote protect ctio ion: n: - Two Two stag stage e nonnon-di dire rect ctio iona nall back up protection. 3.
Neutra Neutrall volta voltage ge displ displace aceme ment nt prote protecti ction: on: - Two Two stag stage e eleme element nt providing protection against earth fault on high impedance earthed system.
4. 100% 100% Stat Stator or earth earth faul faultt prote protect ctio ion: n: - Provi Provide des s prot protec ectio tion n agai agains nstt earth faults close to the generator start point. 5. Under/ Under/ove overr voltage voltage protectio protection: n: - Two stage stage under under voltage voltage and two stage over voltage protection. 6. Under/over Under/over frequen frequency cy protectio protection: n: - Four Four stage stage under under frequency frequency and and two stage over frequency protection. 7. Reverse Reverse power: power: - Protect Protection ion against against loss of of prime prime mover. mover. 8. Low forward forward power: power: - Provides Provides an an interlock interlock for for non-urgent non-urgent trippin tripping. g. 9. Fiel Field d fail failure ure:: - Two Two stag stage e elem elemen entt for for prot protec ecti tion on agai agains nstt loss loss of excitation. 10. Negative phase sequence sequence protection: - Provides protection against against unbalanced loading, which can cause overheating of the generator rotor. 11. Over Over fluxin fluxing: g: - Provid Provides es protec protectio tion n for the generat generator/t or/trans ransform former er against unusual voltage or frequency conditions. 12. Unintentional energisation at standstill standstill (dead machine) protection: Protect Protection ion agains againstt inadve inadverten rtentt closin closing g of the generat generator or circui circuitt breaker when machine is not running.
PAGE 2 OF 58
Other non-protective features of the relay: 1.
Voltage Voltage transforme transformerr supervisio supervision: n: - To prevent prevent mal-opera mal-operation tion of voltage dependent protection elements upon loss of a VT input signal.
2. Measur Measureme ements nts:: - Variou Various s measure measuremen mentt of value value for display display on the relay or accessed from the serial communications e.g. Currents, voltages, Power etc. 3. Fault Fault / even eventt / dist distur urba banc nce e reco records rds:: - Avai Availa labl ble e from from the the serial communication or on the relay display (fault and event records only on relay display. 4. Four Four setting setting groups: groups: - Indepen Independe dent nt setting setting groups groups to cater cater for alternative arrangements or user specific application. 5. Contin Continuou uous s self monito monitorin ring: g: - Power Power on diagnost diagnostics ics and self self checking routine to provide maximum relay reliability and availability. 6.
Circ Circui uitt brea breake kerr stat state e moni monito torin ring: g: - Prov Provide ides s indi indica cati tion on of discrepancy between circuit breaker auxiliary contacts.
PAGE 3 OF 58
PAGE 4 OF 58
Scheme Design: 100% Redundancy: Considering the vital importance of generator protection scheme Two number of P343 relays are used. One used as a Main and other as a redundant. Both the relays will be all the time in service and functions independently. CT/PT circuits, tripping circuits and alarm / interlocking circuits are made independent to achieve 100% redundancy.
Removal of old protective relays Following old Generator Protection relays completely removed along with the associated components
Generator Diff. Protection
Gen. Inter-turn Protection
Gen. Negative Sequence Protection
Gen. Loss of excitation Protection
Gen Back up impedance Protection
Gen. 95% Stator Earth Fault protection
Gen Over voltage protection
Gen over fluxing Protection
Gen over current Protection
Gen. Low forward power protection
Gen Under / Over Frequency Protection
Gen under voltage protection.
Retention of old conventional relays with the modified Generator Protection Scheme Following conventional relays retained in the scheme.
GT overall differential Protection (RADSB).
Gen. Reverse Power Protection (WCD)
GT Restricted Earth Fault Protection.
GT HV Back-Up Over Current Protection (HBB Make)
Local Breaker Back-Up Protection (RAICA)
UAT differential Protection (RADSB). PAGE 5 OF 58
UAT HV Back-Up Over Current Protection (CDG61)
UAT LV Neutral displacement Relay
Gen. PT fuse monitoring Scheme.
Gen. Check Synchronization Relay (SKE11).
Gen. Breaker Trip Circuit Supervision Relay.
Gen. Protection Master Trip Relay for Class A Protection. (86G, 86GT, 86T, 86TT, 86B)
Gen. Rotor Earth-Fault Protection Scheme .
GT & UAT Winding temp, Oil Temp, Buccholz Protection Scheme.
PAGE 6 OF 58
Preparation and Homework Procurement of Relays: Relays: Two numbers of ALSTOM make
microp microproc rocess essor or based based genera generator tor protec protectio tion n relay relay type type P343 P343 procured for this modification
Preparation of scheme and schematic drawings: drawings :
The scheme is design to accommodate the above changes and to ensure adequate protection to the generator, the protection scheme drawings prepared before the shut down. The modified drawings prepared in three sections 1.
Sing Single le line line Dia Diagr gram ams: s: Thi This s cove covers rs the the allo allotm tmen entt of gene genera rato tor r CT & PT for different protection relays. Also it shows the over view of the generator protection scheme.
2.
CT/PT CIRCUITS: This covers the CT/PT Secondary connection details.
3.
Genera Generator tor Protec Protectio tion n contro controll DC circui circuit: t: This This covers covers the different trip commands, alarm and interlocking circuitry up to the final elements of execution.
The The comp comple lete te “Gen “Gener erat ator or Prot Protec ecti tion on Sche Scheme me”” draw drawin ings gs are are enclosed in Annexure B.
PAGE 7 OF 58
Execution of work: •
Above listed old conventional relays removed along with associated wiring and components from the panel.
•
Two number of P343 relays mounted on RA1 Panel
•
Wiring of relays and scheme is done as per approved drawings.
Checking and Testing •
Wiring checking: checking: After completion of installation and wiring work. Wiring is thoroughly checked before charging the scheme with control supply.
•
Charging of control supply: supply: 220 v dc control supply charged and voltage measurements at all the relays checked for correct polarity and magnitude.
•
Interlocking checking: checking: all interlocking circuitry checked thoroughly by operating respective contacts/ contacts/ Relays manually the correctness is checked and confirmed as per drawings.
•
Secondary injection testing : all the relays tested completely by secondary injection method for correctly functioning.
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Calculation of settings for P343
1. Gen Gen differ differen enti tial al prote protect ctio ion n Previous setting = 20mA, 100V Setting for P343 Function- high impedance Is1=250mA Is1=250mA (min available setting) Stabilizing resistance value Rst = Vs/Is1= (1.5*If(Rct+2RL))/Is1 If – maximum through fault current that can flow through the generator From previous SCC results To circulate 9000A stator currents, excitation current required 1920A as there is limit for maximum excitation that is 3200A therefore maximum short circuit stator current corresponding to maximum excitation will be Isc max=(3200*9000)/1920 A = 15000 A (C.T. secondary 7.5 A) Rct+2RL=3.2ohm (measured) Rst=1.5*7.5*3.2/0.25 = 144 ohm Actual set at 400 ohms , to get 100 V differential voltage. 2. Gen Gen pow power er prot protec ecti tion on Operating mode generator a) Revers Reverse e powe powerr protec protectio tion n -P>1 = -20 watts (5.72 MW) minimum setting available on relay selected PSL time settings Electrical RPP = 10 sec Mechanical RPP = 1 sec (interlocked with turbine trip) b) Generator Generator low forwar forward d power power protection protection P>2 = 20 watts (5.72 MW) minimum setting available on relay selected Delay = 2 sec PSL interlocked with turbine trip
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3. Gen field field failur failure e protec protection tion
Previous settings Xa1 = 2 ohm Xa1 +Xb1 = 42.5 ohm Hence Xb1 = 40.5 ohm delay 2 sec sec Setting criteria Xa1 = 0.5*Xd*CTR/PTR Xd = 30.5% = 0.305 pu …………sub-transient reactance reactance of generator Xa1 = 0.5*Xd*(10000/5)*(110/15750) Xd in ohms = Xd (pu)*kv* (pu)*kv*kv/MVA = 0.305*15.75*15.75/247 =0.306311993 ohm Xa1 = 2.139 ohm Nearest settable value is 2.099 ohms Xb1 = Xd * CTR/PTR Xd (ohmic) = Xd(pu)*kv*kv/MVA Xb1 = 2.22*(15.75*15.75/247)*(10000/5)* 2.22*(15.75*15.75/247)*(10000/5)*(110/15750) (110/15750) = 31.14 ohm Nearest settable value is 31.2 ohms Time delay = 2 sec for trip Field fail alarm angle = 25 degrees Alarm delay = 1 sec 4. Negativ Negative e phase phase seque sequence nce prot protect ection ion Original setting Start time capability I22 *t = 8 I2 start = 7.5% Continuous rated I2 = 5% of rated current PAGE 10 OF 58
tmax = 300 sec New settings Alarm I2>1 alarm enabled I2>1 current setting Alarm for 5% for 5% of Im I2> 1 current set = I2 continuous rating (pu)*( Ifull load /Ip)*In Ifull load = rated full load current in primary = 9050 A Ip = Rated C.T. primary current = 10000 A In = Rated C.T. secondary current = 5 A I2>1 (set) = 0.05*9050*5/10000 = 0.226 A Nearest available setting = 200 mA Alarm delay = 2 sec I2>2 trip enabled I2 >2 start = 6% I2>2 set = I2 start (pu)*( Ifull load /Ip)*In = 0.06*9050*5/10000 = 0.271 A Nearest settable value = 250 mA K setting calculations Generator capability for I2 is I22*t = 8 To operate the relay earlier than the capability of generator relay characteristic selected I22*t = 7 in standard format kg = I 22*t hence kg = 7 K = kg*(Ifull load /Ip)2 K = 7*(9050/10000)2 = 5.733 Nearest available setting of K = 5.7
Kreset Kept same as K that is 5.7 I2>2 tmax This is the maximum operating time for negative phase sequence thermal characteristic I2>2 tmax set at 500 sec (minimum setting available) PAGE 11 OF 58
I2>2 tmin This is the minimum operating time and set at 250 msec 5. Gen backup impedance protection
Original setting Z = 1.5 ohms (per phase) Function under impedance Z (G.T.) = 12.5% Ohmic value of Z (G.T.) = Z(pu)*KV2/MVA = 0.125*15.752/250 = 0.124 ohm Impedance protection to be covered up to 220 KV bus bar that is Z = Z(G.T.) Z at C.T.,P.T. secondary level = Z*(CTR/PTR) = 0.124*(10000/5)*(110/15750) = 1.73 ohm For three phase impedance 1.73*sqrt(3) = 2.996 ohm Z<2 set = 3 Ohm (nearest setting available) Time setting = 2.5 sec (considering the line under impedance time setting that is to allow the line protections to clear the fault before tripping of generator) Z<1 setting (for P343 (for P343 main only) Setting criteria: for long faults and sustained overloading the setting of this stage should be kept to operate at 30% overloading i.e. it should be set at 70% impedance of the full load parameters of the generator.
Zfull load at C.T., P.T. level = rated volts (phase to phase)/ Ifull load = 110/4.525 = 24.3 ohms Z 70% = Zfull load*0.7 = 24.3*0.7 = 17.01 ohms Hence Z<1 setting = 17 ohms (nearest available value) Z<1 delay = 5 sec PAGE 12 OF 58
1. Gen therma thermall overl overload oad protect protection ion BHEL supplied the following capability for the generator Current in
%
Time in
KA 9.95 10.41 10.86 11.31 11.76 12.22 12.67 13.57
Overload 1.1 1.15 1.2 1.25 1.3 1.35 1.4 1.5
minute 60 15 6 5 4 3 2 1
As per BHEL generator is capable of continuous over load of 10% hence Ithermal set at 1.12 pu 1.12*9050*5/10000 = 5.068 A nearest available setting is 5.05 A T constant is selected as 7 minutes With With abov above e sett setting ing & allo allowa wabl ble e over over load loads s the the comp compat atib ibilility ity checked. As per relay manual t = T*ln((Ieq2-Ip2) / ( Ieq2-Iset2))
After calculations following are the results
Current in KA
% Overload
Time in
Relay time in minute
minute With I2=0%
9.95 10.41 10.86 11.31 11.76 12.22
1.1 1.15 1.2 1.25 1.3 1.35
60 15 6 5 4 3 PAGE 13 OF 58
10.88 6.04 4.21 3.21 2.59
With I2=5% 10.315 5.88 4.138 3.1759 2.56
12.67 13.57
1.4 1.5
2 1
2.155 1.5
2.1 1.582213
Above characteristics shows relay setting is ok except current above 1.35 times overload to protect this part of overload definite time over current protection 2. Gen over over cur curren rentt prot protecti ection on Iset > 1.35*(9050*5/10000) = 6.108 A Iset > 6.1 A (nearest available setting) Fixed delay 40sec 3. Residual Residual over over voltage voltage of NVD NVD (Generator (Generator stator stator 95% 95% E/F protec protection tion ) Original setting 5.75V 5% of 125 = 6.25V Vn>1 function DT Vn>1 voltage set = 6V (nearest available setting) Time delay = 1 sec 4. 100% 100% stato tatorr E/ E/F It is based on third harmonic under voltage measurement principle henc hence e afte afterr obse observ rvin ing g the the third third harm harmon onic ic comp compon onen entt duri during ng different loading conditions the setting for 100% stator E/F will be decided presently it kept disable.
5. GT over over fluxing fluxing protec protection tion (V/Hz protection) protection) Original setting V/Hz = 2.53 New setting Alarm V/Hz alarm = 2.35 V/Hz Alarm delay = 3.5 sec Trip function IDMT V/Hz set = 2.4 V/Hz, V/Hz, TMS = 4 Trip time t = 0.8+0.18*TMS/(M-1)2 M = V/Hz actual/V/Hz set 6. Gen Gen volta voltage ge pro prote tecti ction on a) Generat Generator or under under volta voltage ge prote protecti ction on PAGE 14 OF 58
only alarm is given for generator under voltage and set at 80% of the rated voltage V<1 voltage set = 88 V, V, with delay 1 sec b) Generat Generator or over volta voltage ge protect protection ion stagestage-II V>1 voltage set at 121 V (10% over voltage) V>1 time delay 5 sec c) Generat Generator or over over voltage voltage protec protectio tion n stage-II stage-II V>2 voltage set at 127 V (15% over voltage) V>2 time delay 500 msec 7. Gen Gen freq freque uenc ncy y prote protect ctio ion n a) Generat Generator or under under freq frequen uency cy alarm alarm F<1 set = 48 Hz F<1 time delay = 1 sec b) Generat Generator or under under freq frequen uency cy trip trip F<2 set = 47 Hz F<2 time delay = 500 msec c) Generat Generator or over over freque frequency ncy alarm alarm F>1 set = 51.5 Hz F>1 time delay = 1 sec d) Generat Generator or over over freque frequency ncy trip F>2 set = 52.5 Hz F>2 time delay = 1 sec Actual settings done and final PSL attached in Annexure C
PAGE 15 OF 58
Conventional Relay Settings and Testing Report (Not Included in P343) 1. Check Check synchr synchron onizat ization ion relay relay Model No. :
SKE11BF550 3B(M)
Sr. No. :
M837347
Rate Rated d Vol Volta tage ge::
63.5 63.5/1 /110 10 Vac, Vac, 50H 50Hz z
<α:
+/- 200
Aux Supply:
220 Vdc
▲v setting:
5%
t- Set:
0.5Sec
Relay Testing ▲v Checking: a. Applied V1 Voltage Voltage (5 & 7) = 110V (fixed) Variable Voltage applied V2 (8 & 10) Relay Picks up at 104 V Relay Drops Out at 102 V b. Applied V2 Voltage Voltage (8 & 10) = 110V (fixed) Variable Voltage applied V2 (5 & 7) Relay Picks up at 106 V Relay Drops Out at 104 V <α Checking V1 and V2 applied voltage = 110 V Phase difference between V1 & V2 Varied and observed Relay operates from -200 to +200 2.
Reverse Power Protection Relay
Relay Type WCD12BF2026A5 Sr. No. 115084J Testing Procedure:
Apply 3 Phase balanced Currents 180 degree to 3 phase applied balanced voltage Voltage Applied = 63.5 V (Phase to Neutral) Go on increasing current till relay operates Relay operated at 11 mA, Drop out 9mA PAGE 16 OF 58
Electrical Reverse Power delay 10.399 Sec ( set 10 Sec) Mechanical Reverse Power delay 2.037 Sec ( set 2 Sec) 3. UAT UAT Diff Diff Prote Protect ctio ion n (87UA (87UAT) T) Relay Type: RADSB RA3:D1:101 101:RXTP18, 107: RXTUG 2H, 113:RTQTB60 In= 1A, 119:RTQTB61 In=1A, 125:RXDSB-4, 137:RXMS-1, 337:RXSGA-1 Setting Range: 3Id /I > Isr = (0.2,---------,0.5) In 3 Id >> Isu = (8, 13, 20) In Adopted Setting: 3Id /I > Isr = 0.2* In = 0.2 A 3 Id >> Isu = 8* In = 8 A Relay Testing Report Operational Test Phas Phase e
Curr Curren entt Inje Injec cted ted
Pick Up
Expected
R
Between 3 – 12
(A) 0.207
0.2
phase Y phase B phase
4 - 13 5 - 14
0.21 0.205 0.284
0.2 0.2 0.34
3 Phase
Through Current Restrain Checking Phase
Current Injected at Ia = 3, Ib = 6, Id =
Ia 0.
Ib 0.53
Id 0.26
% Bais 39.34
12 Ia = 3, Ib = 6, Id =
8 1.
7 0.69
3 0.31
36.68
12 Y phase Ia = 4, Ib = 7, Id =
0 0.
0.54
0.26
13 Y phase Ia = 4, Ib = 7, Id =
8 1.
0 0.68
0 0.31
38.80597
13 B phase Ia = 5, Ib = 8, Id =
0 0.
9 0.54
1 0.25
36.82652
14 B phase Ia = 5, Ib = 8, Id =
8 1.
6 0.69
4 0.30
37.74146
0 1.
8 0.61
2 0.38
35.57126 47.37168
R phase R phase
14 3phase
PAGE 17 OF 58
0
7
3
% Bais = 100*Id/(Ib + 0.5*Id) 4. UAT 95% 95% Earth Earth Fault Fault Prote Protecti ction. on.(64 (64UAT UAT)) RA3:D1:101 101:RTXP18, 107: RXIG 28, 307:Filter Unit, 119:RXKB1, 319:RXSF-1 Setting Range: (1,-------,3)*5 V Tim Time Sett Settin ing g Ran Range ge::
(00— (00—99 99)* )* 10 msec sec
Adopted Setting: 6V, 1 Sec Delay Relay Testing Report Voltage Applied Between:
9 & 10
Pick Up Value:
6.1 V
Drop Out Value:
6.0 V
5. UAT HV HV Over Over Current Current Prot Protect ection ion (50/ (50/51 51 UAT) UAT) Relay Type:
CDG61 EG 111ZMCH
Sr. No.:
130534770409002
In:
5A
Setting Range: PS:
(2.5, 3.75, 5, 6.25, 7.5, 8.75, 10) A
Inst:
LK1 (50* K), LK2 (25*K), LK3 (12.5* K): K: (1.2 -----2)
Setting Adopted: PS: 5 Amp, TMS: 1 Inst: LK2(25), K= 1.6, = 40A Relay Testing Report Instantanious Element Test Phas
Settin
Actual
Expected Value
e R Y B
g 40 A 40 A 40 A
Value 40 A 40.5 A 40 A
40 A 40 A 40 A
Induction Pick Up Test Phas
Settin
Pick
Drop
Expected
e R Y
g 5A 5A
Up 5.0 A 5A
Out 4.98 A 4.99 A
5A 5A PAGE 18 OF 58
B
5A
5.03 A
4.98 A
5A
Charectristic Checking Phas
Settin
Current
Expected trip
Actual Trip Time
e R Y B
g 5A 5A 5A
Injected 10 A 10 A 10 A
time 3.85 Sec 3.85 Sec 3.85 Sec
3.92 Sec 3.95 Sec 3.77 ec
6. Voltag Voltage e Bala Balanc nce e Schem Scheme e (60G) (60G) RA3:D25:101 101:RTXP18 Test switch 107, 119, 131: RXEG21
Metering PT
307, 319, 331: RXEG21
AVR PT
507, 519, 531: RXEG21
Protection PT
Setting Range: (1-------3)*40 V Relay
Pick
Drop Out
Metering
up 48.8 V
47.8 V
R Metering Y Metering B AVR R AVR Y AVR B PROT R RROT Y PROT B
48.0 V 48.5 V 43.6 V 42.9 V 42.6 V 45.5 V 44.5 V 45.7 V
46.9 V 47.6 V 42.7 V 42.10 V 41.6 V 44.5 V 43.7 V 44.7 V
7. Over Over all all Diff Diff Protec Protectio tion n (87G (87GT) T) Relay Type: RADSB RA3:D1:101 101:RXTP18, 107: RXTUG 2H, 113:RTQTB60 In= 5A, 119:RTQTB61 In=5A, 125:RXDSB-4, 137:RXMS-1, 337:RXSGA-1 Setting Range:
PAGE 19 OF 58
3Id /I > Isr = (0.2,---------,0.5) In 3 Id >> Isu = (8, 13, 20) In
Adopted Setting: 3Id /I > Isr = 0.2* In = 1.0 A 3 Id >> Isu = 8* In = 40 A Relay Testing Report Operational Test Phas Phase e
Curr Curren entt Inje Injec cted ted
Pick Up
Expected
R
Between 3 – 12
(A) 1.02
1.0
4 – 13 5 – 14
0.99 1.014 1.406
1.0 1.0 1.7
phase Y phase B phase 3 Phase
Through Current Restrain Checking Phase
Current Injected at
I
Ib
Id
R
Ia = 3, Ib = 6, Id =
a 5
3.4
1.5
phase
12 Ia = 3, Ib = 6, Id =
9 1.3
37.81213
4
1 2.6
1 1.4
39.16293
5
9 3.5
8 1.2
34.74178
4
2 2.7
1 1.4
35.64065
5
9 3.5
7 1.2
34.46659
4
3 2.7
5
6 3
4 2
36.68639 50
R phase
12 Y phase Ia = 4, Ib = 7, Id = 13 Y phase Ia = 4, Ib = 7, Id = 13 B phase Ia = 5, Ib = 8, Id = 14 B phase Ia = 5, Ib = 8, Id = 14 3phase
% Bais
% Bais = 100*Id/(Ib + 0.5*Id) 8. GT Restri Restricte cted d Earth Faul Faultt Protect Protection ion(64 (64GT) GT) Relay Type RADHD RA4:D5:101 101:RTXP18, 107:RXTLA1, 113:RXTCA1, 307:RXID1, 313:RXSF1 Setting: 97 V fixed PAGE 20 OF 58
Relay Testing Report Voltage Applied Between:
3&4
Pick Up Value:
93.5 V; (17.9 mAmp)
Drop Out Value:
70.2 V; (13.3 mAmp)
PAGE 21 OF 58
GEN PROTECTION TESTING REPORT DURING ANNUAL OVERHOUL OF UNIT4 Dec -2007
Relay testing report Gen Protection Relay P343 Main Relay Sr. No 072605C Current Injected at RA1: TTB1 FOR R,Y,B & N respectively except for diff. protection Voltage Injected at out terminals of PT fuses for the relay 1. Gener Generator ator Differe Differenti ntial al Prote Protecti ction on Phas e R
Setting Adopted 250 mA 250 mA 250 mA
Operating Value 250 mA 250 mA 250 mA
2. Gener Generator ator Reve Reverse rse Powe Powerr Protect Protection ion.. Setting Adopted -P>1 -5.72 MW (20 Watt)
Operating Value Pick-Up -5.76 MW (0.106A)
Time Delay Checking Set Actual Value Delay 10 Sec 10.0463 Sec 1 Sec 1.048 3.
Remark
Drop -Out -5.35 MW (0.099 A)
3 Phase Nominal Voltage Injected (63.5 V)
Remark Without 86TT With 86TT
Generator Low Forward Power Protection. Protection.
Setting Adopted P>2 5.72 MW
Operating Value •
5.657 MW •
Remark Relay Tested with 86TT operated Actual delay 2.048 Sec (set 2 Sec) 3 Phase Nominal Voltage Injected (63.5 V)
4. Field Failure Protection. Protection.
Alarm Checking
Setting Adopted 25 Degree (Lead)
Operating Value 25.09 Degree (lead)
Remark Checked in both generating and Motoring mode
PAGE 22 OF 58
FF1 settings Xa1 = 2.1 ohm Xb1 = 30.2 ohm
OB = Xa1 + Xb1 = 2.1 + 30.2 = 32.23 ohm OA = Xa1 = 2.1 ohm Test Procedure: Checking of Point “B” 1. Apply 3 Phase Phase balanced balanced Currents Currents 90 degree degree leading leading to to 3 phase phase applied balanced voltage 2. Voltag Voltage e Applie Applied d = 63.5 V (Phase (Phase to to Neutra Neutral) l) 3. Go on incre increasi asing ng curre current nt till relay relay oper operate ates s 4. Relay operated at 1.98 A 5. Actual X =63.5 /1.98 = 32.075 ohm Checking of Point “A” 6. Apply 3 Phase Phase balanced balanced Currents Currents 90 degree degree leading leading to to 3 phase phase applied balanced voltage 7. Curr Curren ents ts Appl Applied ied = 5.3 5.3 A 8. Go on incre increasi asing ng Volta Voltage ge till till relay relay operat operates es 9. Relay operated at 11.15 V (Phase to Neutral) 10. 10. Actual X =11.15 / 5.3 = 2.10 ohm 11. Delay Checked actual actual delay 2.0248 sec (Set at at 2 Sec) 5. Gen Negat Negative ive Phase Phase Seque Sequence nce Prote Protecti ction on
Settings Adopted: I2 > 1 Alarm I2 > 1 Current Set = 200 mA I2 > 1 Time Delay = 2 Sec. I2 > 2 Trip I2 > 2 Current Set = 250 mA. I2 > 2 K Setting = 6.5 Sec. I2 > 2 K Reset = 6.5 Sec
Alarm Checking PAGE 23 OF 58
Single Phase Current injection Iinj = I2/ 0.577 Expected Iinj = 200/0.577 = 346.6 mA
Phase R-Y Y-B B-R
Setting Adopted 200 mA 200 mA 200 mA
Expected Value 346.6 mA 346.6 mA 346.6 mA
Operating Value 350 mA(I2 403.1A) 350 mA(I2 403.4A) 350 mA(I2 402.5A)
Trip Time Checking T = - K (ln (1-((I2 Set)*( I2 Set)/(I2*I2)) I2 Set* I2 Set T= time in sec. K = K set = 5.7 Sec I2 = Actual I2 in P.U. I2 Set = I2 st in p.U. = 0.06 Trip Timing for 20% I2 T= -(5.7/0.06*0.06)ln(1-(0.06*0.06/0.2*0.2)) T = - (1583.34)ln(1-(0.09)) T = 149.3 Sec. Sec. Current Injected for 20% I2 = 5*0.2/0.577 = 1.73A
Actual Time = 148.18 Sec. Sec. 6. Under Impedance Protection: Protection: Settings Adopted: Z < 1 set = 17 ohm Z < 2 set = 3 ohm
Test Procedure for Z1: 1. Apply 3 Phase Phase balanced balanced Currents Currents & 3 phase phase applied applied balance balanced d voltage PAGE 24 OF 58
Desk Meter 4.4% 4.4% 4.4%
2. Voltag Voltage e Applie Applied d = 63.5 V (Phase (Phase to to Neutra Neutral) l) 3. Go on incre increasi asing ng curre current nt till relay relay oper operate ates s 4. Relay Relay oper operat ated ed at 6.5 A 5. Actual X = 63.5*1.73 / 6.5 = 16.92 ohm 6. Delay Delay actu actull 5.0242 5.0242 Sec (Set at 5 Sec) Sec) Test Procedure for Z2: 7. Apply 3 Phase Phase balanced balanced Currents Currents & 3 phase phase applied applied balance balanced d voltage 8. Curr Curren entt injec injecte ted d Applie Applied d = 5A 9. Go on decreasing voltage till relay operates 10. Relay operated operated at 8.6 V 11. 11. Actual X = 8.6*1.73 / 5 = 2.98 ohm 12. Delay actul 2.5429 Sec (Set at 2.5 Sec) 7. Thermal Over load: load: Settings Adopted: Thermal I> 5.05 Thermal Alarm = 90% T Heating = 7 min T cooling = 7 Min M factor = 3 Ieq = SQR(I1*I1 + 3 *I2*I2) Testing Procedure: Single phase injection Current injected Between R & B Phases I1 = 0.577 Iinj. I2 = 0.577 Iinj. Ieq = 1.154 Iinj t = T ln(((Ieq*Ieq)-(Ip*Ip))/(( ln(((Ieq*Ieq)-(Ip*Ip))/(( Ieq*Ieq)Ieq*Ieq)- (th Set* Ith Set))) t = 7 ln(((1.154Iinj*1.154Iinj)-(0)/(( 1.154Iinj*1.154Iinj)-(5.05*5.05))) For Iinj = 5 A t = 609.96 sec Actual time = 609.6262 Sec 8. GT over over flux fluxing ing Protec Protectio tion: n: Setting adopted: V/Hz Alarm = 2.352 V/Hz Trip Function IDMT V/Hz Trip Set = 2.4 TMS = 4
V/Hz Trip Alarm Checking Apply 3 Phase Balanced Voltage = 63.5 V (Phase to Neutral) Go on reducing frequency till relay operates Actual Value = 46.76 Hz Actual V/Hz = 63.5*1.73/46.76 = 2.35212 Trip time Characteristic Checking t = 0.8 + 0.18*TMS/(M-1)*(M-1) M = V/Hz (actual) V/Hz (set)
PAGE 25 OF 58
V (phase to phase) 135V 138.56V
Hz 45 40
Expected time 12.32 Sec 4.46 Sec
Protection: 9. Voltage Protection:
Over Voltage Protection Stage 1 Settings Adopted V>1 set = 121 V Actual Value: Pick up = 121.07 V, Drop out = 118.57 V Actual delay 5.045 Sec (Set at 5.0 Sec) Over Voltage Protection Stage 2 Settings Adopted V>2 set = 127 V Actual Value: Pick up = 127.01 V, Drop out = 124.24 V Actual delay m Sec (Set at 500 m Sec) 10. 10. Frequency Protection: Protection:
Under Frequency Alarm Settings Adopted F<1 set = 48 Hz Actual Value = 48 HZ Drop out = 48.03 Hz Actual delay 1.178 Sec (Set at 1.0 Sec) Under Frequency Trip Settings Adopted F<2 set = 47 Hz Actual Value = 47 HZ Drop out = 47.03 Hz Actual delay 717 mSec (Set at 500 mSec) Over Frequency Alarm Settings Adopted F>1 set = 51.5 Hz Actual Value = 51.5 HZ Drop out = 51.47 Hz Actual delay 1.1544 Sec (Set at 1.0 Sec) Over Frequency Trip Settings Adopted F>2 set = 52.5 Hz Actual Value = 52.51 HZ Drop out = 52.47 Hz Actual delay 1.21 Sec (Set at 1.0 Sec) 11. Gen Over Current Current Trip Settings Adopted I>1 set = 6.1 Amp Actual Value = 6.1 Amp Drop out = 5.77 Amp Actual delay 40.05 Sec (Set at 40Sec) 12. 95% Stator Earth Fault Protection Settings Adopted PAGE 26 OF 58
Actual Time 12.35 Sec 4.54 Sec
Vn>1 set = 6.0 Volt Actual Value = 6.02 Volt Drop out = 5.71 volt Actual delay 1.05 Sec (Set at 1Sec)
PAGE 27 OF 58
Gen Protection Relay P343 Redundant Relay sr. No. 130504130351001 Current Injected at RA1 TTB 4 FOR R,Y,B & N respectively except for Inter turn protection Voltage Injected at Out terminals of PT fuses for the relay 13. 13. Generator Inter Turn Turn Protection
Phase
Setting Adopted 250 mA
Operating Value 253 mA (253 A) 253 mA (253 A) 253 mA (253 A)
250 mA 250 mA
Drop Out
Delay
241 mA (241A) 241 mA (241A) 241 mA (241A)
1.01 Sec (set at 1 Sec) 1.04 Sec (set at 1 Sec) 1.04 Sec (set at 1 Sec)
14. Gen Over Current Current Trip Settings Adopted I>1 set = 6.1 Amp Actual Value = 6.1 Amp Drop out = 5.79 Amp Actual delay 40.053 Sec (Set at 40Sec) 15. Generator Reverse Reverse Power Protection. Setting Adopted -P>1 -5.72 MW (20 Watt) Time Delay Checking Set Actu ctual Va Value lue Delay 10 Sec 10.0143 Sec 1 Sec 1.047
Operating Value Pick-Up -5.73 MW (0.105A)
Drop -Out -5.32MW (0.098)
Remark 3 Phase Nominal Voltage Injected (63.5 V)
Remar emark k Without 86TT With 86TT
16. 16. Generator Low Forward Power Protection. Protection.
Setting Adopted P>2 5.72 MW
Operating Value 5.625 MW( 0.103 mA)
Remark Relay Tested with 86TT operated Actual delay 2.041 Sec (set 2 Sec)
PAGE 28 OF 58
17. 17.
Fiel Field d Failu ailure re Prot Protec ecti tion on.. Alarm Checking
Setting Adopted 25 Degree (Lead)
Operating Value 25.07 Degree (lead)
delay Actual delay 1.05 Sec (set at 1 Sec)
FF1 settings Xa1 = 2.1 ohm Xb1 = 30.2 ohm
OB = Xa1 + Xb1 = 2.1 + 30.2 = 32.23 ohm OA = Xa1 = 2.1 ohm Test Procedure: Checking of Point “B” 1. Apply 3 Phase Phase balanced balanced Currents Currents 90 degree degree leading leading to to 3 phase phase applied balanced voltage 2. Voltag Voltage e Applie Applied d = 63.5 V (Phase (Phase to to Neutra Neutral) l) 3. Go on incre increasi asing ng curre current nt till relay relay oper operate ates s 4. Relay operated at 1.972 A = 32.2 ohm 5. Actual X =63.5 /1.972 Checking of Point “A” 6. Apply 3 Phase Phase balanced balanced Currents Currents 90 degree degree leading leading to to 3 phase phase applied balanced voltage 7. Curr Curren ents ts Appl Applied ied = 5.3 5.3 A 8. Go on incre increasi asing ng Volta Voltage ge till till relay relay operat operates es 9. Relay Relay opera operated ted at at 11.15 11.15 V (Phas (Phase e to Neutra Neutral) l) 10. 10. Actual X =11.143 / 5.3 = 2.10 ohm 11. 11. Delay Checked actual delay 2.06 sec (Set at 2 Sec) 18. Gen Negative Phase Phase Sequence Protection
Settings Adopted: I2 > 1 Alarm : PAGE 29 OF 58
I2 > 1 Current Set = 200 mA I2 > 1 Time Delay = 2 Sec. I2 > 2 Trip: I2 > 2 Current Set = 250 mA. I2 > 2 K Setting = 6.5 Sec. I2 > 2 K Reset = 6.5 Sec
Alarm Checking Single Phase Current injection Iinj = I2/ 0.577 Expected Iinj = 200/0.577 = 346.6 mA
Phase R-Y Y-B B-R
Setting Adopted 200 mA 200 mA 200 mA
Expected Value 346.6 mA 346.6 mA 346.6 mA
Operating Value 349 mA(I2 402.5A) 349 mA(I2 402.5A) 349 mA(I2 402.5A)
Trip Time Checking T = - K (ln (1-((I2 Set)*( I2 Set)/(I2*I2)) I2 Set* I2 Set T= time in sec. K = K set = 5.7 Sec I2 = Actual I2 in P.U. I2 Set = I2 st in p.U. = 0.06 Trip Timing for 20% I2 T= -(5.7/0.06*0.06)ln(1-(0.06*0.06/0.2*0.2)) T = - (1583.34)ln(1-(0.09)) T = 149.3 Sec. Sec. Current Injected for 20 I2 = 5*0.2/0.577 = 1.73A
Actual Time = 148.24 Sec. Sec. 19. 19. Under Impedance Protection: Protection: Settings Adopted: Z < 1 set = 17 ohm Z < 2 set = 3 ohm
PAGE 30 OF 58
Remark
Test Procedure for Z1: 1. Apply 3 Phase Phase balanced balanced Currents Currents & 3 phase phase applied applied balance balanced d voltage 2. Voltag Voltage e Applied Applied = 63.50 63.509 9 V (Phase (Phase to Neutra Neutral) l) 3. Go on incre increasi asing ng curre current nt till relay relay oper operate ates s 4. Relay Relay oper operat ated ed at 6.48 6.48 A 5. Actual X = 63.509*1.73 / 6.48 = 16.97 ohm 6. Delay Delay actu actull 5.035 5.035 Sec Sec (Set (Set at 5 Sec) Sec) Test Procedure for Z2: 7. Apply 3 Phase Phase balanced balanced Currents Currents & 3 phase phase applied applied balance balanced d voltage 8. Curr Curren entt injec injecte ted d Applie Applied d = 5A 9. Go on decre decreasi asing ng volta voltage ge till rela relay y operate operates s 10. Relay operated operated at 8.66 8.66 V 11. 11. Actual X = 8.66*1.73 / 5 = 2.99 ohm 12. Delay actul 2.53 Sec (Set at 2.5 Sec)
20. 20. GT over fluxing Protection: Protection:
Setting adopted: V/Hz Alarm = 2.352 V/Hz Trip Function IDMT V/Hz Trip Set = 2.4 TMS = 4
V/Hz Trip Alarm Checking Apply 3 Phase Balanced Voltage = 63.509 V (Phase to Neutral) Go on reducing frequency till relay operates Actual Value = 46.78 Hz Actual V/Hz = 63.509*1.73/46.78 = 2.3514 Delay 3.75 sec (set at 3.5sec) Trip time Characteristic Checking t = 0.8 + 0.18*TMS/(M-1)*(M-1) M = V/Hz (actual) PAGE 31 OF 58
V/Hz (set) V (phase to phase) 135V 138.56V
Hz 45 40
Expected time 12.32 Sec 4.46 Sec
21. 21. Voltage Protection: Protection:
Over Voltage Protection Stage 1 Settings Adopted V>1 set = 121 V Actual Value: Pick up = 121.01 V, Drop out = 118.59 V Actual delay 5.1 Sec (Set at 5.0 5.0 Sec) Sec) Over Voltage Protection Stage 2 Settings Adopted V>2 set = 127 V Actual Value: Pick up = 127.02 V, Drop out = 124.46 V Actual delay 552 m Sec (Set at 500 m Sec) 22. 22. Frequency Protection: Protection:
Under Frequency Alarm Settings Adopted F<1 set = 48 Hz Actual Value = 47.99 HZ Drop out = 48.04 Hz Actual delay 1.178 Sec (Set at 1.0 Sec) Under Frequency Trip Settings Adopted F<2 set = 47 Hz Actual Value = 47 HZ Drop out = 47.03 Hz Actual delay 740 mSec (Set at 500 mSec) Over Frequency Alarm Settings Adopted F>1 set = 51.5 Hz Actual Value = 51.5 HZ Drop out = 51.47 Hz Actual delay 1.1544 Sec (Set at 1.0 Sec) Over Frequency Trip Settings Adopted F>2 set = 52.5 Hz Actual Value = 52.51 HZ Drop out = 52.47 Hz Actual delay 1.21 Sec (Set at 1.0 Sec) 23. 23. Thermal Over load: load: Settings Adopted: Thermal I> 5.05 Thermal Alarm = 90% T Heating = 7 min T cooling = 7 Min PAGE 32 OF 58
Actual Time 12.41 Sec 4.55Sec
M factor = 3 Ieq = SQR(I1*I1 + 3 *I2*I2) Testing Procedure: Single phase injection Current injected Between R & B Phases I1 = 0.577 Iinj. I2 = 0.577 Iinj. Ieq = 1.154 Iinj t = T ln(((Ieq*Ieq)-(Ip*Ip))/(( ln(((Ieq*Ieq)-(Ip*Ip))/(( Ieq*Ieq)Ieq*Ieq)- (th Set* Ith Set))) t = 7 ln(((1.154Iinj*1.154Iinj)-(0)/(( 1.154Iinj*1.154Iinj)-(5.05*5.05))) For Iinj = 5 A t = 609.96 sec Actual time = 609.942 Sec 24. 95% Stator Earth Fault Protection Settings Adopted Vn>1 set = 6.0 Volt Actual Value = 6.02 Volt Drop out = 5.71 volt Actual delay 1.05 Sec (Set at 1Sec)
PAGE 33 OF 58
Alarm and trip protection trial protocol: Date
Annunciation and Protection Tripping T Trials rials After completion of generator protection panel wiring work following annunciation and protection trials taken in presence of operation staff 1. Gen Gen pro prote tect ctio ion n DC DC fai faill P343M/M11-M12 P343R/ M11-M12 +B Failed (Remove fuse) +T Failed (Remove fuse) +GT Failed (Remove fuse) +G Failed (Remove fuse) +TT Failed (Remove fuse) 2. Gen Gen Diffe Differe rent ntia iall Trip Trip P343M/K3-K4 3. Gen. Gen. Inte Intertur rturn n Prot Protect ection ion Trip Trip P343R/ K3-K4 4. Gen Gen Sta Stato torr E/F E/F Trip Trip P343M/J9 – J10 P343R/ J9 – J10 5. Gen Over Over Volta Voltage ge Prot Protect ection ion Trip Trip P343M/J7 – J8 P343M/J7 – J8 6. Gen NPS NPS Trip P343M/L11-L12 P343R/H15-H14 7. GT Ov Over er Flux Fluxin ing g Trip Trip P343M/H1 – H2 P343R/ H1 – H2 8. Gen Backup Impedance Protection Trip P343M/J15 –J14 P343R/ J15 –J14 9. Gen Gen Loss Loss of of Exci Excita tati tion on Trip Trip P343M/K1-K2 P343R/K1-K2 10. Gen RPP Trip Trip P343M/K5-K6 P343R/ K5-K6 WCD /1-2 Observe Master trip operation 86GT WCD/11-12+86TT operated Observe Master trip operation 86GT 11. Gen Frequency Trip (U/F or O/F) P343M/K7-K8 P343R/ K7-K8 PAGE 34 OF 58
OK OK OK OK OK OK OK OK OK OK OK OK OK OK OK OK OK OK OK OK OK OK OK OK OK OK OK OK OK
12. Gen Thermal Thermal O/L or O/C Trip
P343M/K9-K10 P343R/ K9-K10 13. Gen LPF LPF Trip P343M/H5 – H6 P343R/ H5 – H6 14. Gen Over Current Current Alarm Alarm P343M/K14-K15 P343R/K14-K15 15. Gen RPP Plain P343M/K17-K18 P343R/K17-K18 16. Gen NPS NPS Alarm Alarm P343M/J1-J2 P343R/J1-J2 17. Gen Over Voltage Voltage Alarm Alarm P343M/J3 – J4 P343R/J3 – J4 18. Gen Under Frequency Alarm Alarm P343M/J5-J6 P343R/J5-J6 19. Gen Over Frequency Frequency Alarm Alarm P343M/J11-J12 P343R/ J11-J12 20. Gen Over Fluxing Fluxing Alarm Alarm P343M/H3 – H4 P343R/H3 – H4 21. Gen Under Excitation Alarm / Under Voltage Alarm P343M/H7 – H8 P343R/H7 – H8 22. Gen CT/ CT/ VT Fail Fail P343M/H9 – H10 P343R/H9 – H10 23. P343M/L1-L2 P343M/L1-L2 (R1 Class Class A Trip) Master trip operation 86G Alarm 24. P343R/L1 – L2 (R1 Class A Trip) Master trip operation 86T Alarm 25. P343M/L3-L4 (R2 Class B Trip) Master trip operation 86B Alarm 26. P343R/ L3-L4 (R2 Class B Trip) Master trip operation 86B Alarm 27. Gen Rotor Rotor E/F AC Fail Fail Make AC supply off(SF96) 28. Gen Rotor E/F Short ( RA2/X4/101 -104) and observe Rotor E/F Stage II Operated PAGE 35 OF 58
OK OK OK OK OK OK OK OK OK OK OK OK OK OK OK OK OK OK OK OK OK OK OK OK OK OK OK OK OK OK OK
OK
Rotor E/F Stage II Operated Master Trip Relay 86GT Operated 29. Gen Rotor E/F Protection Out Put the switch on +/- to Earth 30. UAT Oil Temp Temp Alarm Alarm Short RA3/X4/114 -115 31. UAT Oil Temp Trip Short RA3/X4/116 -117 Master Trip Relay 86GT Operated 32. UAT Winding Winding Temp Temp Alarm Short RA3/X4/112-113 33. UAT Winding Temp Trip Short RA3/X4/110 -111 Master Trip Relay 86GT Operated 34. UAT Differentia Differentiall Trip Short RA3:D1:101:125:421 -425 Master trip operation 86GT Alarm 35. Excitation Excitation Class Class A Trip Short RA3/X4/105 -106 No alarm only operation of 86GT 36. UAT Buccholz Buccholz Alarm Short RA3/X4/108-109 37. UAT Buccholz Trip Short RA3/X4/108 -107 Master Trip Relay 86GT Operated 38. UAT Over Current Trip Master trip operation 86GT 39. Serious Serious Turbine Faults Short RA3/X4/118 – 119 No alarm only operation of 86GT 40. GT R/E/F R/E/F Trip For Alarm 307:17 - 18 For Trip 307:15 -25Master trip operation 86GT 41. GT Buccholz Alarm Short RA4/X4/101-103 42. GT Buccholz Trip Short RA4/X4/102 -104 Master Trip Relay 86GT Operated 43. GT HV Back Up Over Current Trip 44. GT Winding Winding Temp Alarm Short RA4/X4/105-109 45. GT Winding Temp Trip Short RA4/X4/106 -110 Master Trip Relay 86GT Operated 46. GT Oil Temp Temp Alarm Short RA4/X4/107 -111 47. GT Oil Temp Trip Short RA4/X4/108 -112 Master Trip Relay 86GT Operated PAGE 36 OF 58
OK OK OK OK OK OK OK OK OK
OK OK
OK OK OK OK OK OK
OK OK OK OK OK OK OK OK OK OK OK OK OK
48. GT PRV Operated Operated Trip Short RA4/X4/116 -117 Master Trip Relay 86GT Operated 49. GT Overall Differential Trip Short RA3:D1:101:125:421 -425 Master trip operation 86GT Alarm 50. Gen LBB Operate Operated d Short 331:23 -24 51. 220 KV Bus Bar Protection Operated Operate 96L manually and observe Alarm Master trip operation 86T 52. Excitation Excitation Class Class B Trip Short RA3/X4/131 -132 No alarm only operation of 86B 53. Stator Water Conductivity Very High Short RA3/X4/133 -134 No alarm only operation of 86B 54. UAT 95% E/F protection Short 107:118 -117 only Alarm 55. Stator Water Flow very low Short RA5/X4/191 -192 (delayed) No alarm only operation of 86B 56. Oil Level in damper damper tank very low Short RA5/X4/194 -193 (delayed) No alarm only operation of 86B 57. Metering Metering PT fuse Fail Short 307:117 – 118 58. AVR PT fuse Fail Short 507:117 – 118 59. Protection Protection PT fuse Fail Short 107:227 – 228 60. Operation of 86TT Short RA3/X4/165 -166 Alarm Gen 220 KV Breaker Protection and ON/OFF ON/ OFF Trials
OK OK OK OK OK OK
OK OK
OK
OK OK
OK
OK OK OK OK
OK
1. Breaker Local ON-OFF trial taken stood
2. Breake Breakerr remote remote ON-OFF ON-OFF trial trial taken taken 3. Synchronization circuit interlocking checked 4. Breake Breakerr clos closed ed and tripped tripped on gene genera rato torr diff differe erent ntial ial prote protect ctio ion n throu through gh P343 P343M M relay relay.( .(86 86G) G) Gen. Interturn Protn through P343R relay. (86T) Gen. RPP by shorting WCD /1 – 2 (86GT) Sd/-
OK OK OK OK OK OK Sd/-
Gen. Desk Operator
JE (Testing II) PAGE 37 OF 58
220 KV Back Charging Activity for Synchronizing circuit checking for unit 4 Date: 08/01/2008 •
GT HV Links removed
•
220 KV isolators 29AL, 29DL Closed
•
Gen 220 KV breaker closed.
•
Synchroscope showing 12 o clock Position
•
Delta V showing 4%
•
Check Synchro lamp showing clearance
•
PT Voltages measured at SKE relay
Termina l
Voltage
5–7
105
8 - 10
108
Ok
Ok
Breaker tripped on 86T master trip operation through P343R
AE(Test – II)
Operation Unit 4
PAGE 38 OF 58
GT local panel annunciation trials Unit #4 Sr n o 1 2 3 4 5 6 7 8 9
1 2 1 3
Operation
Date 12/01/2008 Remark
GT Buccholz alarm (By shorting 1T 35 – 1T 36 in marshaling box box ) GT Buccholz trip (By shorting 1T 34 – 1T 33 in marshaling box box ) GT HV winding temp high alarm By operating WTI GT HV winding temp high trip By operating WTI GT LV winding temp high alarm By operating WTI GT LV winding temp high trip By operating WTI GT oil temp high alarm By operating OTI GT oil temp very high trip By operating OTI GT PRV operated (By shorting 1T 29 – 1T 30 in marshaling box box ) (By shorting 1T 31 – 1T 32 in marshaling box box ) GT conservator oil level low (By shorting 1T 37 – 1T 38 in marshaling box box ) A) Pumps start and stop from local when selection is on local
Ok Ok Ok. 94o C Ok. 106 106o C Ok. 94o C Ok. 106 106o C Ok 84o C Ok 95o C Ok.
Ok Ok Ok
B) Pumps start and stop from MCC when selection is on MCC C) Pumps selected on remote I) Pump selected on manual mode a) Pump A Start and Stop b) Pump B Start and Stop c) Pump A RUN and Pump Pump B STANDBY selected Pump A get started on wdg temp 54 degree d) Pump B RUN and Pump A STANDBY selected Pump B get started on wdg temp 54 degree
Ok Ok
Ok Ok
II) Pump selected on auto mode a) Both Pumps pickup along with pump ON annunciation at HV wdg temp 85 o C and dropout at 78o C b) Both Pumps pickup along with pump ON annunciation at LV wdg temp 85 o C and dropout at 78o C c) Stand by Pump pickup when selected pump dropout d) Select Pump gets ON when FB ON contact simulated
PAGE 39 OF 58
Ok Ok
PAGE 40 OF 58
UAT local panel annunciation trial Unit #4 Date Jan 12, 2008 Sr n o 1
2
Operation
Power supply trial Both main & standby supply made ON from turbine board a) Main supply switch made OFF (in Marshaling box) Found supply changeover to standby after 20 sec. b) Main supply made ON Found supply changeover to main after 20 sec. Control Supply trial Normal supply fed from CCT-I (415/240 V) a) Remove CCT I fuse (in ( in Marshaling box) and observe supply change over to CCT-II b) Put CCT I fuse (in Marshaling box) box) and observe supply change over to CCT-I
Remark
Ok
Ok
3
Manual mode cooling fan trial Fan No. 3, 5 and 6 stars directly irrespective of selection as it is having only MCB
Ok
4
Auto mode Fan trial by operating HV WTI manually Selector switch kept on auto Fans 1, 2 & 4 get started at 58 degrees Fans 1, 2 & 4 get stopped at 48 degrees UAT Buccholz alarm ( short TB T2 – T3 in Marshaling box ) UAT Buccholz trip ( short TB T2 – T1 in Marshaling box ) UAT LV winding temp high alarm By operating WTI ( T11- T12 ) UAT LV winding temp very high trip By operating WTI ( T13- T14 ) UAT oil temp-high alarm By operating OTI ( T5- T6 ) UAT Oil temp very high trip By operating OTI ( T7- T8 ) UAT Conservator oil level low ( short TB T15 – T16 in Marshaling box )
Ok.
5 6 7
8
9
1 0 1 1
PAGE 41 OF 58
Ok. Ok Ok 95o C Ok. 105 105o C Ok 84o C Ok 90o C Ok
Generator Testing 1. Generator winding resistance measurement Phase Resistance milliohm
in
R-N
Y-N
B-N
R-Y
Y-B
B-R
1.773 2
1.776 9
1.743 2
3.42 6
3.39 1
3.394
2. Generator HV Testing: Taken by M/S Mahale, Pune a. IR Test before HV test: IR Value measured by Evershed Megger with 1KV Phas e
IR15
IR60
IR600
PI
R
2000 Mohm
5000 Mohm
19000 Mohm
3.8
Y
1800 Mohm
4900 Mohm
17000 Mohm
3.46
B
1900 Mohm
4900 Mohm
18000 Mohm
3.67
b. HV test with 16KV for 1min. Temp during test- 330 Phase
R
Y
B
Leak Leakag age e Curr Curren entt in mill millii amp amp
114 114 8
113 113 2
1120
c. IR Test after HV test: IR Value measured by Evershed Megger with 1KV Phas e
IR15
IR60
R
1800 Mohm
5000 Mohm
Y
1700
5000 Mohm
PAGE 42 OF 58
Mohm B
2000 Mohm
5100 Mohm
PAGE 43 OF 58
3. Rotor Impedance Test Voltage (Vac)
Current (Iac)
Impedance (Z)
26
10.8
2.407
49
19.3
2.538
74
26.5
2.792
100
32.9
3.0395
126
38.4
3.281
151
42.4
3.561
175
46.8
3.739
200
50.1
3.992
225
54
4.166
303
65.5
4.625
326
68.8
4.738
348
71.8
4.846
4. Rotor Resistance Test Rotor Resistance = 93.89 milliohm at 30 0 Measured with motwane make micro-ohm meter
5. Transformer Testing: After completion of maintenance works Gen. Transformer, UAT, Excitation Transformer tested for confirming healthyness the test results are enclosed in annexture D
PAGE 44 OF 58
Dynamic testing Modifications for dynamic testing Following Modification done for Slow Built up / Dynamic Testing of Unit No. 4 Generator Excitation System: HV Supply to Excitation Transformer : Removed the HV Power connections of excitation transformer from 15.75 KV bus bar and extended 6.6KV Power supply to excitation transformer from unit bus. 2. Manual Pot Modification (To facilitate the excitation to start from O V) 1.
3.
4. 5.
6.
7. 8.
Spare digital reference unit UN8001 prepared with R1005 = 3.32 K (Original value 4.7 K) R1004 = 4.7K (Original value 3.32K) This will facilitate manual UST at minimum position to –1V to –2V Rest of resistances and links kept as it is i.e. links 1006 – Closed 1007 – closed & Resistances R1002 – Open R1003 – 53 K ohm Replace existing man pot with above AFR Unit Supply: 230Vac is separately extended to 19TY(n), 20TY from 10TY(n) & 11TY(p) respectively. (Original wires coming from 275R &276R kept removed) AR10 AR104 4 re remove moved d To inhibit FFB closing & bypass the FF disturb protection. Thyrister Fan Supply: Thyrister fan supply is extended separately from EB through FF fuses. Remove outgoing wires of FS107, FS108 & FS109. Remove internal wires of 34FF, 35FF &36FF. Extend 3 phase supply from FS107, FS108 & FS109 to 34FF, 35FF &36FF respectively. Tier fan supply: (To extend Station Supply to Tier Fans)4of MCB6 is disconnected (wire No.) supply extended to 4 of MCB6 from 4 of MCB3 MCB3 T4 supply. 17R and 18R looped to bypass GCB ON contact. (To Extend Class B Tripping) FB closing interlock ( To Extend 6.6 KV breaker ON Interlock for FB closing) Remove loop between FB36 & FB32 and connect wires from 6.6KV breaker (Aux Contact ) 3A17 & 3A18 to FB36 & FB32 respectively. Rest of the FB closing interlocks are retained i.e. ULR reset, Auto/Man pot at homming position.
PAGE 45 OF 58
9. 6.6KV 6.6KV Breaker protection to FB Tripping: (contact of
51R, Y, B , 86, 6.6KV breaker off, PB in FB cubical are connected in parallel brought to 52FB, 53FB for FB tripping Rest of the trippings kept as it is i.e. ULR, Remote PB, Tripping on AR36.
10. 10. 6.6KV breaker tripping: Spare contacts of AR35 relay
(AR3, AR4 ) extended to 6.6KV breaker tripping.
11. 11. 6.6 KV Breaker closing:
12. UN2007 UN2007 MCB mode OFF OFF 13. Auto channel UN1001 UN1001 racked out. 14. Thyrister fan supply fuse unit F25 isolated. 15. Cable schedul schedule e
PAGE 46 OF 58
PAGE 47 OF 58
After Slow built up modifications following trials / Tests Carried out 1. Man Man Ust Ust Meas Measur urem emen entt At Pot Position Min Ust = -1.71 V At Pot Position Max. Ust = 2.093 V 2. Thyrister Thyrister fan trials: trials: All All Thyrister Thyrister Fan Fan started started and directi direction on trials trials taken taken stood OK. 3. Tier fan trial: Regula Regulation tion supply supply made made on and confirme confirmed d tier fan is running. 4. 6.6 kv settings: settings: CTR 100/5 inst set = 12.5 Amp, PSM = , TMS = 5. Excitat Excitation ion Transf Transform ormer er IR value value Measure Measureme ment nt LV to Earth = 10 Mohm. HV to Earth = 200 Mohm Megger Voltage = 500V 6. FB & 6.6 KV KV feeder feeder protection protection / Interlock Interlock / ON – OFF Trials Trials taken taken and found OK 7. Excitation Excitation transformer transformer charged charged from from 6.6 6.6 KV & Following Following measurements taken Phase Sequence checked at trunking Cubical found OK Voltage measured at trunking cubical VRY = 236 Vac VYB = 235 Vac VBR = 236 Vac Voltage measured at Regulation cubical Voltage measured at Manual Filter 1-2 = 155 Vac 2-3 = 154 Vac 3-1 = 154 Vac Voltage measured at VR1 2-3 = 155 Vac 3-4 = 154 Vac 4-2 = 155 Vac • •
• •
•
•
•
•
Voltage measured at tier Panel RU08/ 74-75 = 158 Vac 75-76 = 158Vac 76-74 = 158 Vac Voltage measured at tier Panel RU08/ 43-44 = 157 Vac 44-45 = 157 Vac 45-43 = 158 Vac Voltage measured at Final stage Terminal TY TY TY RU12 1 2 3 10-11 160 160 160 11-12 159 159 159 12-10 160 160 160
PAGE 48 OF 58
TY4 160 159 160
8. Manual Manual Chan Channel nel DC Suppl Supplies ies Measu Measurem rement ent RU 08/ +15V = 15 Vdc - 15V = - 14.8 Vdc 5V = 4.8 Vdc UL = 18.8 Vdc Ust = -1.71 Vdc 9. Final Final Stag Stage e DC Suppl Supplies ies Check Checking ing Terminal RU12 30-7 -8 -9 -10
TY1 5V 15 V -15.13 V 24.9 V
TY2 5.18 V 15.03 vdc -15.15 V 25.2 V
TY3 5.02 V 15.06 V -15.25 V 25.3v
TY4 5.22 V 14.65 V -15.4 V 25.3v
10. Dummy Load Testing of Excitation system taken as follows
Sr
MAN UST
Firing angle degree
TY-I Vdc
-1.71 (min)
223.2
-1.33 V -0.93 V -0.56
208.8
13 V
201.6
22 V
190.8
0.00 V
180
+0.97
158.4
1.35
147.6
1.71
136.8
2.09 (max)
122.4
28.73 V 38.1 V 117.1 V 158.1 5V 198.9 V 245 V
Idc
TY-II
Y-III
TY-IV
Common
Vdc
Idc
Vdc
Idc
Vdc
Idc
Vdc
Idc
0V
50mA
5V
0.10 A
5V
0.10A
5V
0.06A
0.26 A 0.4 A
14.75 V 22 V
0.26 A
0.26 A
15.2 V
0.22A
0.4 A
22.6 V
0.275 A 0.4 A
11 V
0.4 A
19 V
.35A
0.513 A 0.625 A 1.95 A 2.78 A 3.6 A
29.9 V
0.52 A
14.75 V 22.6 V 30 V
0.52 A
29.8 V
.65 A
8V
0.71A
47 V
0.88 A
47 V
0.88 A
48 V
0.89 A
47 V
0.88A
115.85 V 158.15 V 196.8 V 242 V
1.9 A
1.9 A
108 V
2.0 A
13 V
.11A
2.78 A
115.1 V 158 V
2.78 A
151 V
2.7 A
85 V
3.45A
3.6 A
197 V
3.6 A
187 V
3.6 A
243 V
4.54A
4.5 A
245 V
4.5 A
243 V
4.6 A
253 V
5.78A
4.6 A
Dynamic Testing of Generator : Dynam Dynamic ic testin testing g proce procedur dure e is newly newly devel develop oped ed and and ipmlem ipmlemen ented ted in unit unit 4. The detailed procedure is enclosed in Annexture E TA set rolled and dynamic testing performed the detailed result of dynamic testing is enclosed herewith in annexure E
PAGE 49 OF 58
Normalization and Synchronization: •
•
•
Normalized the modifications for dynamic testing. Protec Protectio tion n trials trials and interloc interlock k trials trials of FB / excita excitatio tion n System System is taken taken satisfactory. Rolled the TA set to 3000 rpm and synchronized the unit No. 4 to the grid at 12.50 Hrs. on 05/02/2008.
On Load Measurements of Generator Parameters After synchronization on load measurements are done. Print outs of the same are enclosed in annexure E
Setting of 100% Stator Earth Fault: Following table shows the measurement of 3rd Harmonic component of Gen. Neutral voltage Sr. No. No.
Description
1.
Single Fault
2.
Phase
3rd Voltage to
Earth
Harmonic
Remark
10.25 v
During Dynamic Testing
At 5 KV Gen Voltage
50.51 V
During Open Circuit Test
3.
At 7 KV Gen Voltage
69.46 V
During Open Circuit Test
4.
At 10 KV Gen Voltage
98.93 V
During Open Circuit Test
5.
At 15 KV Gen Voltage
124.2 V
During Open Circuit Test
6.
At 15.75 KV Gen Voltage
187.1 V
During Open Circuit Test
7.
At 7.812 MW
187.9 V
After Synchronization
8.
At 192 MW
526 V
After Synchronization
PAGE 50 OF 58
According to above observations, 3rd Harmonic Under Voltage setting should be less than 50 V (in secondary term 350 mV) Setting Adopted = 300 mV (Nearest Available Setting) With delay = 5 Sec
PAGE 51 OF 58
ANNEXTURE “A”
TEST – II OFFICE – NOTE Date: 15/05/2006 Sub: Sub: Appr Approv oval al for for Modi Modifi fica cati tion on of Gene Genera rato torr Prot Protec ecti tion on Sche Scheme me with with microprocessor based Integrated Generator Protection Relay. Generator is a having vital importance in the generating stations. It is one of the expensive equipments installed in thermal power plant. Hence it is worth to have reliable and accurate protective system for the generator. Though the protective relays cannot prevent the faults to occur but the correct protection system can definitely avoid or minimize the secondary damage to the generator under fault condition or running under abnormal working conditions this includes external faults, working beyond capability, etc. Nowada Nowadays ys it is utmost utmost to know know the exact picture picture of occurr occurrenc ences es happened in the system. The occurrence may be happened due to internal (Gen) fault or it may be due to external (Grid) reason, the analysis of occurrence is very much important. Exact analysis can save lot of downtime and ultimately money. Presently ABB Make Electromagnetic Generator protection Scheme is in service at Parli Unit No. 4 since commissioning commissioning of the unit. The relays are of old technology and the setting ranges are limited. Hence it is difficult to set the relays accurately, according to the generator capabilities. The event event loggin logging g and disturb disturbanc ance e record recording ing is not availa available ble with with existing existing relays. Hence it is difficult to analyze analyze the fault / events events occurred and the tripping analysis is based on imagination only.
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The on-line healthiness checking is not available with existing relays. This is always creating doubt in the mind about the availability of protection. The existing existing relays relays are deteri deteriora oratin ting g due to ageing ageing and heatin heating g of relays
(the voltage dropping resistances are provided inside the relays and
relays gets heated up). The deterioration is like hardening of internal control wire, dry soldering of PCBs and cases of mal operations also noticed. Simi Simila larr modif odific icat atio ion n has has been been done done in unit unit No. No. 3 and and work workin ing g satisfactory since oct. 2005. during this period it proved the imporatance of disturbance recording during AC failuere and during the different disturbances occurred. Also these relays are used in unit no. 2 during rehabilitation after fire. The same relays are also being used in new parli. Cons Consid ider erin ing g the the abov above e it is nece necess ssar ary y to chan change ge the the gene genera rato tor r protection scheme by Microprocessor based integrated Generator protection relays. Considering the vital importance of generator protection scheme two numbers of relays are proposed (One as main and other as Redundant). The relays proposed to procure vide G. O. – 2 / CS 93 clause No. 6 Total estimated amount for 2 relays is Rs 2200000/Budget provision is already made in 2006-07. Submitted for approval please. Sd/Executive Engineer TIC, St-II Sd/Superintendent Engineer Op. St-II Sd/General Manager
Sd/-
TPS, Parli-V. PAGE 53 OF 58
Chief General Manager TPS, Parli-V.
ANNEXTURE B TESTING – STAGE II OFFICE NOTE Date: 02/06/2007
Sub: - Approval for the Modifications / Modified Generator Protection Scheme Scheme Drawings Drawings With Microproce Microprocessor ssor Based Based Gen Protectio Protection n Relays Relays Micom P343. For unit No. 4 Generator During proposed shut Down. Pres Presen entl tly y ABB ABB make make prot protec ecti tion on rela relays ys syst system em is used used for for Unit Unit 4 Generator. The protection relays are of old version (ABB make static relays) and the accuracy and reliability have deteriorated due to aging. Hence it was decided to replace the relays with microprocessor based integrated relays. In line with this, P343 Areva make generator protection relays (2 Nos) are under procurement. Following major works involves in the modifications. I. Foll Follow owin ing g conv conven enti tion onal al rela relays ys to be remo remove ved d alon along g with with asso associ ciat ated ed wiring. 2.
Generator Diff. Protection
3.
Generator Inter Tu Turn Protection
4.
Gen Gen. Negative Sequence Protec tection
5.
Gen Gen. Loss of excitati tatio on Protec tectio tion
6.
Gen Ba Back up up im impedance Pr Protection
7.
Gen Gen. 95 95% Sta Stattor Ea Earth Fault pro prottectio tion
8.
Gen Over voltage protection
9.
Gen over fluxing Protection
10.
Gen Gen over cu current Pro Prote tec ctio tion
11. 11.
Gen Gen. Low Low forw forwa ard power prote rotec ction tion
12. 12.
Gen Gen Und Under er / Ove Over Fre Freq quency ncy Pro Prote tect ctiion
13.
Gen Gen un under vo voltag tage pro prote tec ctio tion.
14.
Gen Gen Re Reverse Po Power Pr Protection
II. Two numbe numberr micom micom P343 P343 relay commi commissi ssioni oning ng (One as Main Main and other other as redundant).
PAGE 54 OF 58
III. Followin Following g convention conventional al relays relays are to be be retained retained in the the scheme. scheme. 1. GT overall overall differenti differential al Protectio Protection n (RAD (RADSE). SE). 2. Gen. Gen. Reverse Reverse Power Power Prote Protecti ction on (WCD) (WCD) to be install installed ed as a back up protection 3. GT Rest Restric ricted ted Eart Earth h Fault Fault Prote Protecti ction. on. 4. GT HV Back-U Back-Up p Over Curre Current nt Protec Protectio tion n (P111) (P111) in place place of old relay HBB make 5. Local Local Breake Breakerr BackBack-Up Up Prote Protecti ction on 6. UAT UAT differe differenti ntial al Protec Protectio tion n (RADSE (RADSE). ). 7. UAT UAT HV Back-Up Back-Up Over Over Curre Current nt Protec Protectio tion n (P111) (P111) in place place of old relay HBB make 8. UAT UAT LV Neu Neutra trall displ displace acemen mentt Relay. Relay. 9. Gen. Gen. PT PT fuse fuse monito monitorin ring g Sche Scheme me 10. Gen. Check Check Synchronization Synchronization Relay Relay (SKE11). (SKE11). 11. Gen. Breaker Trip Circuit Circuit Supervision Relay. 12. Gen. Protection Master Master Trip Relay Relay for Class A Protection. Protection. 13. 13. Gen. Gen.
Roto Rotorr
Eart Earthh-Fa Faul ultt
Prot Protec ecti tion on
Sche Scheme me
(VAE (VAEM3 M33 3
&CAEM33). to replace old relay ABB Make 14. 14. GT & UAT UAT Wind Windin ing g temp temp,, Oil Oil Temp Temp,, Bucc Buccho hoz z Prot Protec ecti tion on Scheme. For accommodation of above changes and to ensure adequate protection to the generator, the protection scheme drawings have been modified / prepared. The modified proposed drawings are prepared in three t hree sections •
Single line Diagrams: This covers the allotment of generator CT & PT for different protection relays. Also it shows the over view of the generator protection scheme.
•
CT/PT CIRCUITS: This covers the CT/PT Secondary connection details. details.
•
Generator Protection control DC circuit : This covers the different trip commands, alarm and interlocking circuitry up to the final f inal elements of execution. The Proposed Proposed Modificati Modification on Drawings Drawings are submitted submitted herewith herewith for kind perusal & approval please
Sd/Superintending Superintending Engineer (Gen)
Sd/Executive Engineer (Gen) T,I&C STAGE-II
ELECTRICAL STAGE – II
Sd/General Manager (Gen) TPS Parli-V PAGE 55 OF 58
Sd/Chief General Manager (Gen.) TPS Parli-V
PAGE 56 OF 58
