SiemensNumerical Pilot Protection 7SD52 using digital wide-band communication Protection and Substation Control EV S 1 Siemens Numerical pilot protection relay 7SD52 Universally applicable to power system configurations up to six ends , containing : OH-Lines Cables Transformers For digital data transmissen Protection and Substation Control Via dedicated optical fibres Via Communication networks EV S 2 Siemens Numerical Pilot Differential Protection Principle IA IB IAS , IAC I I IBS , IBC ID +j operate IA IAC stabilize IB ID IBS IAS IB + Operate : ID = IA +IB Bias: IB = IA + IB Operating Criterium: ID K1 + K2 . IS IBC IA = IAS + j IAC IB = IBS + j IBC Protection and Substation Control EV S 3 Siemens Definition of Synchronous Phasor: measured at different locations based on a common time reference Time reference i i A B Location : A Location : B I M I B Relay A B I R E B Relay B Protection and Substation Control EV S 4 . Siemens Numerical pilot protection: Advanced Fourier analysis of the currents . . n IS(k) i(k ni ) i k-n I(k) IS(k) j IC(k) k IC(k) I (k ) j IC(k) cos 2 i n Protection and Substation Control IS(k) EV S 5 .Supress DC components. . harmonics sin 2 i n 0 1 2 . Optimized filtering coeffizients for 7SD52 -> Suppress DC 4 times better than conventional Fourier-filters -> Archieve high sensitivity i0 i1 i2 iN t 0 1 2 3 .. Protection and Substation Control N iO iN N1 2 IC cos ω n Δt in N 2 2 n1 EV S 6 ..Siemens Advanced Fourier Transformation .. N 2 N1 IS sinω n Δt in N n1 n 0 1 2 3 ... Siemens Advanced Full Cycle Fourier analysis: Filter characteristic Protection and Substation Control EV S 7 . Siemens Orthogonal Current Components (Advanced Fourier Filter) t I(t) 1 Ø IS I ( t) sin t dt 2 Ø -360 =0 I (Ø) I S j I C I 0 1 j 0 I 1 IC 2 Ø I (t) cos t dt Ø .360 I 30 3 1 j I 2 2 j IC I I 60 1 3 j I 2 2 t t=0 IS I 90 0 j1 I Protection and Substation Control EV S 8 . . tA1 tL1 tA5 tB2 tV tA3 tA4 tB1 tB3 tL2 tV t B3 t A1 .tL2) x (360O/Tperiod) Protection and Substation Control EV S 9 .Siemens Numerical Pilot Differential Relay Propagation Time Measurement and Phasor Angle Correction A B I I IS(A .tA1.. I C(B IB(tA3) Propagation time: tL1= tL2= 1/2 x (tA-reception .. ) tA1 tA2 IC(A ) .tV) Corrected sampling instant: tB3= tA-reception -tL2 IB(tB3) = (tB3 .. tB4 ) I S(B).. Tarrival / B->NY + Tarrival / NY->B . Tdepart / B->NY (6:00) --------------------> Tarrival / B->NY (8:00) From the flight back from New York to Berlin the local departure time in NY and the arrival time in Berlin is: T arrival / NY->B (23:00) <--------------.6:00 + 23:00 .9 Uhr)/2 = 6 hours (-> difference between the time zones) Protection and Substation Control EV S 10 .Tdepart / NY->B ) / 2 Time difference = (Tdepart / B->NY . Each relay has it´s own 1 us resolution timer.Tdepart / NY->B ) / 2 Duration = (8:00 .8 Uhr + 23 Uhr . The time difference between NY and B and the duration of the flight (transmission time) Duration = ( T arrival / B->NY . = (6 Uhr .T depart / NY->B (9:00) Under the assumption. The reason are the different time zones.9:00) / 2 = 8 hours (-> delay time) Time diff. that the flight to New York and the flight back from NY have the same duration the relevant time results can be calculated.Siemens Example for the delay time calculation Flight from Berlin <-> New York You can not calculate the duration of a flight if you look at the clock in Berlin on departure and later note the local New York time on arrival..T depart / B->NY+ T arrival / NY->B . The relays are also in two time zones. Siemens Coded message of current differential protection 7SD52 HDLC FRAME FORMAT Opening Flag 01111110 Address Field (A) 16 bits relays address Control Field (C) 8 or 16 bits Synchronizing Information Field (I) any length 0 .N bits time data status + command Frame Check Seqence (FCS) Closing Flag 32 bits 01111110 message validation Current vectors Protection and Substation Control EV S 11 . or of a data transmission network PCM MUX PCM MUX (Protection and PCM-device not in the same room) Protection and Substation Control EV S 12 .F. Wire.703 Further services: Telefon. b) Channel of a data transmission system or of a data transmission network (Protection and PCM-device in the same room) PCM MUX PCM MUX Multimode optic fibres 850 nm I O.Siemens Numerical pilot differential protection: Communication options Monomode fibre 1300 ober 1550 nm I I a) Dedicated optic fibre I Further services: Telefon. etc.703 Optic fibre or Microwave I G. Multimode optic fibres 850 nm O. Data transmission. I Further services: Telefon. G. Data transmission. etc.703 Wire G. b) Channel of a data transmission system. etc. G.703 Optic fibre or microwave Further services: Telefon. Data transmission.F. etc. Data transmission. Siemens Application for a three terminal configuration Monomode fibre optic cable up to 10 km (1300 nm modul) Monomode fibre optic cable up to 35 km with 1300 nm interface Distance relay 7SA52 X21 G703.1: 64 kBit X21: N*64 kBit (1N8) Protection and Substation Control EV S 13 .1 820 nm Option: I-REGB time synchronisation max. 3 km e o PCM multiplexer SDH comms-network PCM multiplexer o e Commsconverter G703. Overload protection Option: 5 fast trip contacts .Siemens Numerical line differential protection 7SD52 Scope of functions / Hardware options .For system configurations with up to 6 terminals 3Iph.Autoreclosure 1/3 pole 24 binary inputs 32 contacts .Sensitive current phasor differential .4 remote commands.Inrush restraint (2nd harmonic) and vector group adaption ½*19´´ .Fast high set charge comparision (subcycle trip) . and IE 4U 8 binary inputs 16 contacts 1 .CT saturation detector 16 binary inputs 24 contacts .2 protection interfaces System interface PC-interface Time synchronisation .Switch on to fault protection . 24 remote signals Protection and Substation Control 1*19´´ EV S 14 . 5 km (with clock feed-back) distance 3km 1300 nm 10 km FO7 : distance 10km 1300 nm 35 km FO8: distance 35km internal O internal O internal O E X21 G703 KU : hook-up to communication network external Km data for worst-case conditions Protection and Substation Control EV S 15 .5 km / 3 km FO5: FO6 : distance 1.Siemens Communication Options O 820 nm 1. standard Interfacemodul 2 RS485 or FO service-interface Interfacemodul 1 RS485 or FO or RS232 DIGSI local Browser local-PC interface Serial time sync.Siemens Hardware option of the comms interfaces Protection interface 2 Remote line end 2 Port E Synchronous N x 64kB/sec Remote line end 1 2 D5 7S Plug in modules Protection interface 1 Port D Synchronous N x 64kB/sec Subst. also for modem connection and Browser GPS-receiver EV S 16 . input Protection and Substation Control Substation control DIGSI 4. control interface communication modules FO (Fibre optic) or RS485 or RS232 Available Protocols IEC . Interfaces Main processor board of the relay Sockets for the communication modules Protection and Substation Control EV S 17 .Siemens Main board of the relay with it´s Communication . fundamental frequency 87L 0 87L Every 5ms (128-512 bBit). <1cycle 5 i dt 5 i dt Phasor differential For high resistive faults IDiff> Setting: 0.Siemens Adaptive Algorithm: Fast Charge comparison and very sensitive Phasor differential Charge comparison Fast normal trip stage IDiff>> Setting: 0.2 IN 0 1 cycle Phasor.1-0. 10 ms (64 kBit) Protection and Substation Control EV S 18 .67*ILoadmax/IN Fast. trip I2 I3 I1 I2 restrain IDiff> 0.5 Calculated Phasor sum: Minimum pick-up: Restrain: IDiff = I1 + I2 + I3 I3 Irestr I1 IN.Siemens Adaptive differential relaying Consideration of CT. IDiff = Ilow set IRestrain = c.load.Betr. tolerance + Syncronising tolerance trip condition: IDiff >Ilow set and IDiff > IRestraint Protection and Substation Control EV S 19 .t.and communication-errors IDiff IN.15 I1 load Through fault 0. 5.2 C.t.1 and c.t. 4 • IC sensitive set point at short lines. Pick-up value: minimum 0.2 I2 I1 Source V1 I1 C.IDiff .t.Siemens Spill Current through Line Charging Capacitances Protected Zone defined by c.t. IC = I1 + I2 Difference equals charging current IDiff> >2. 1 IDiff IC Source V2 Kichhoff equation: I1 + I2 .1 IN Protection and Substation Control EV S 20 ..IC = 0 Service conditions: IDiff = 0. 1 • I1 Resulting set point Set points: Percentage bias related to c. errors IDiff = 10.05•I1 IC j U L CL IDiff=0.5 • IN = IN Protection and Substation Control EV S 21 .5 • IN .I1´ + I2´| = f1• I1 + f2 • I2 Load: I1 = IN IDiff=0.9.95•I1 I2 I1 IC I2´=1. errors IDiff IDiff = |.t.1• IN Through Fault: I1 = 10 • IN IDiff> I1 Minimum pick-up related to line charging current • IDiff> set point > line charging current • Percentage bias > Sum of c.t. error and line charging I1 -I1 I1 I1´=0.Siemens Setting above spill currents: c.t.1 • I1 = 0. Siemens Approximated c. fB < 3%.t I1 : parameter 7SD52 Example: 10P10.t. Tolerance Basis for the restraint current calculation IDiff I1 Fault current tolerance Tolerance of a real CT Load current tolerance ALFe / ALFN • IN.c. fK at ALFN = 10% Protection and Substation Control EV S 22 . s total error at accuracy limit nN = 5% with class. e..g.0.1.t. 5P20..t. 3% with 10P c. 5P and 10% 10 P Protection and Substation Control EV S 23 .2 * RN RN at 10 VA 10 => Ri 2 ALFe ALFN = Pi + PN Pi + PB 2 VA + 10 VA 2 VA + 1 VA With PB = Pleads + Prelay (0.Siemens Current transformer data C.1 VA) = 4 Resulting Relay Parameter: • effective ALF / nominal ALF = 4 (calculation as per above) • IEC 44 -1: tolerance in load area up to ALFe / ALFN : 1% with 5P. Parameter c.t. 10VA % tolerance at ALFN ALFe = ALFN Thumb rule: Ri 0. 05 + 800 A • 0.5 • 100 A + 800 A • 0.load = 0.01 + 5600 A • 0.01 + 400 A • 0.load = 0.5 • 100 A + 4800 A • 0.063 Case 2 (Through fault) IRest = 2.01) fSC 2 = 5% (0.load = 0.load = 1600 A 1200 A 5600 A 400 A 800 A IStab = 2.01) fSC 1 = 5% (0.05) 800 A 4800 A IC = 100 A 10P10 10 VA 400:1 ALFe/ALFN = 1 fLoad 3 = 3% (0.03 = 282 A Idiff = 100 A I restr / IN.41 I Diff / IN. error currents IDiff = actual deviation of vector summation and charge summation Case 1 (Through load) IRest = 2.176 I Diff / IN.025 Protection and Substation Control EV S 24 .t.5 • line charge currents (basic restraint value) + c.1) 5P20 20 VA 1600:1 ALFe/ALFN = 2 fLoad 2 = 1% (0.load = 0.03) fSC 3 = 10% (0.1 = 658 A IDiff = 40 A I restrain / IN.05) IN.Siemens Internal restraint current calculation due to CT-errors The restraint current is the sum of the maximal expected CT-errors 5P20 20 VA 1600:1 ALFe/ALFN = 5 fLoad 1 = 1% (0.01 + 1200 A • 0. Siemens CT Saturation detector based on harmonic analysis ct I2 ct I1 Harmonic content of the differential current 2 |fn| |f1| 0 t Id = I1 .I2 0 0 Harmonic order 10 t Protection and Substation Control EV S 25 . Siemens Charge comparison: Operating Principle I1 I3 protected Line configuration I4 Q diff=Q 1+Q 2+Q 3+Q 4 Q1 I2 Q part1=Q 1 7SD52 Q part2=Q 2+Q 3+Q 4 1 Protection and Substation Control Q2 Qdiff 2 Q3 Q part2=Q 1+Q 2 Q4 Q part3=Q 1+Q 2+Q 3 7SD52 Q part3=Q 3+Q 4 7SD52 Q part4=Q 4 3 4 EV S 26 . Operating characteristic. errors qdiff12. Tripping times |Q | diff Operate (internal fault) Charge calculation by numerical integration t 1 Q Q 1 t 0 ing nd e ep ed p slo t 2 t 3 t 4 DIFF > t 6 Current Measuring window 5 ms (50 Hz) Corrected time instants after end-to-end time synchronisation Protection and Substation Control f dif Settable pick-up value =IDiff>> t 5 on Q Restraint Area Calculated charge restraint value from CT-errors . synch.Siemens Charge Comparison: Charge calculation.dsf QRest Relay calculates the charge. Setting as current value I Diff>> speed 64 kbit/s 128 kbit/s 512 kbit/s (FO) 2 relays 21 ms 16 ms 14 ms 3 relays 21 ms 16 ms 14 ms EV S 6 relays 41 ms 24 ms 17 ms 27 . Siemens 7SD52 Pilot Protection: Sliding data windows faultinception current. voltage voltage current time 5 ms charge and 20 ms phasor data windows Protection and Substation Control EV S 28 . 20 ms) Counts number of invalid telegrams Blocking the diff.IRIG-B) (If signal transmission time depends on the transmission direction. N settable from 1 . Online high resolution fault recorder) Protection and Substation Control EV S 29 .protocol Permanent supervision of the data transmission Measurement and compensation of signal transmission time (max.network Step 2: Microsecond exact time synchronisation via satellite (civil .8. synchronous HDLC-protocol) Communication device addresses (Protection devices are clearly assigned to a defined protection section) Detection of reflected data in the loops in comms.protection if transmission failure rate is too high Settings for the data transmission (N*64 kBit/s.Siemens Familiar with digital communication networks Features of the relay to relay communication Synchronous data transmission by HDLC. relays I3 I3 I1 I3+I1 I1+I2 side 1 Partial current summation EV S 30 . if one connection is lost or not available side 2 side 2 I2 side 3 I2 Connection to side 3 I3 I3+I1 I2 I1+I2 I1 side 1 Closed ring Protection and Substation Control other diff.Siemens Ring and Chain topologie Automatic change from closed ring to chain. Siemens Breaker-and-a-half Scheme. Through Fault Stabilisation 87L To remote end busbar 2 If = through fault current If = through fault current busbar 2 busbar 1 Partial differential Protection and Substation Control 87L To remote end 87L busbar 1 Full differential EV S 31 . Protection Interface PI1 6 PI1 Protection and Substation Control PI2 5 PI1 PI2 4 EV S 32 . 6 line ends 1 PI1 PI1 2 PI2 PI1 3 PI2 PI .Siemens Topologies: Chain topology for max. 6 line ends 1 PI2 PI1 2 PI2 PI1 3 PI1 PI2 PI2 PI1 6 PI1 PI2 5 PI1 PI2 4 PI .Protection Interface Protection and Substation Control EV S 33 .Siemens Topologies: Ring topology. Siemens Web-Browser based commissioning tool Protection and Substation Control EV S 34 . Siemens 7SD52: Commisioning and Monitoring using Web-Browser Protection and Substation Control EV S 35 .