La protection sélective des réseaux électriques

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Baldwin Pearson
5 years ago
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1 La protection sélective des réseaux électriques ULG

2 The T&D grids Generation Transmission Distribution Industry

The electricity network ensure an efficient supply of energy High Voltage Transformers Medium Voltage Components, switchgear and turnkey projects for AC and DC

Components, switchgear and turnkey projects for AC and DC power technology for power transmission 52 kv.

3 The electricity network ensure an efficient supply of energy High Voltage Transformers Medium Voltage Components, switchgear and turnkey projects for AC and DC power technology for power transmission > 52 kv. Power transformers, distribution transformers with oil or cast-resin insulation. Components, switchgear and turnkey projects for AC and DC power technology for power transmission 52 kv. Energy Automation Network control systems, protection and substation automation, telecontrol systems, power quality. Services Network planning & consulting, asset maintenance and maintenance management for grids and networks, metering services.

4 Energy flow in electricity networks Main power station Wind Hydro Biomass 150 kv 15 kv Combined industrial processes kv 150 kv Fuel cell Storage 0. 4 kv 0. 4 kv Solar Domestic Industry Combined heat power Domestic

5 Key Product for High Voltage Network: Circuit Breaker 80 Rated short-circuit breaking current [ka] 63 3AT2/3 3AT4/ , AP1 FG 3AP1 FI 3AP2 FI 72, Rated voltage [kv]

6 Products for High Voltage Arrestors, Bushings, Coils & Instrument Transformers Arrester HV: AIS (Porcellain, Polymer) & GIS; HVDC, FACTS MV: Distribution & Traction Vehicles Coils Air Core Dry Type Reactors Line Traps Arc Suppression Coils Bushings Air Core Dry Type Reactors Line Traps Arc Suppression Coils Instrument Transformers Current Transformers Voltage Transformers

7 Gas Insulated Switchgear (GIS) 8DN9 switchgear Rated voltage Rated frequency Rated power frequency up to 245 kv 50 / 60 Hz withstand voltage (1 min) up to 460 kv Rated lightning impulse withstand voltage (1,2/50 µs) up to 1050 kv Rated busbar current Rated feeder current up to 3150 A up to 3150 A Rated breaking current up to 50 ka Rated short-time current up to 50 Leakage rate per year and gas compartment < 0.5 % Bay width Bay height Bay depth Bay weight 1500 mm 3500 mm 4700 mm 5 t ka

8 Medium Voltage Components Vacuum Tubes High reliability Excellent field experience with more than 2 million vacuum interrupters Tailormade development Wide product range for any application For use in LV and MV circuit-breakers, load-break switches and contactors Autoreclosers Transformer Tap Changers Delivery Program 690 up to 1300 V up to 65 ka up to 2500 A 7.2 up to 40.5 kv up to 72 ka up to 6300 A

Energy Automation Information and Do lor

9 Energy Automation Information and Do lor situs cum habilitarum network control itum technology alus causticus imanenter Protection Status and landum substation exus auto- rius laudanum tum. mation, telecon-trol systems, power Lorem quality exit vulnareus plexus est. Vulna pausta rhus tex, per itum falor sit wunt. Sit itum causticus aurum eum et expli ndus.cum

10 First objectives of the SELECTIVE PROTECTION -detect fault and isolate only the faulted part of the power system -ensure the greatest possible level of the grid and supply reliability -limit the effect of faults on the equipments (cable, transformer,..)

11 SIPROTEC 4 LE SYSTEME DE PROTECTION = TI/TP + Relais+ Disjoncteur Sélectif,rapide,fiable

12 Reliability of the protection relays X R 1. Fast operation Limit damages 2. High accuracy High selectivity 3. Signal distortion does not cause delay or maloperation

13 SIPROTEC more than 100 Years of Experience Analog Relays Electromechanical Relays Numerical Protection Relays

14 O/C protection

15 Time-overcurrent protection Functions Time-overcurrent protection Criteria for fault: Criteria for selectivity: overcurrent time

16 Time-overcurrent protection Characteristics Tripping characteristic of a two stage time-overcurrent protection device - definite time t [sec] Tripping area I> I>> x I N

17 Time-overcurrent protection Application Main protection as line protection x x x x O/C O/C O/C O/C t = 900ms t = 600ms t = 300ms t = 0ms Ttrip b a ck u p distance Advantage: simple device, only current transformers are necessary Disadvantage: near infeed higher tripping time

18 Distance protection

19 Why impedance protection? Situation: Meshed network and two infeeds Directional overcurrent time relays 0,6s 0,3s 0,6s 0,3s 0,6s 0,3s 0,6s non-selective trip 0,3s

20 Basic principle of impedance protection Localization of short-circuits by means of an impedance measurement: fault on the protected line relay A Z1 fault outside the protected line relay A Z2 selectivity

21 Distance measurement (principle) I L1 I L2 I L3 I E Z L Z Z L = R L + j X L Z E = R E +j X E U L1 U L2 U L3 E 6 loops: 3 phase- phase loops and 3 phase- ground loops phase- phase -loop: U L1-L2 = Z L ( I L1 - I L2 ) Measured current measured voltage The same applies to the remaining loops dtgerdis3

22 Distance measurement (principle) I L1 Z L I L2 Z L = R L + j X L I L3 I E Z Z E = R E +j X E U L1 U L2 U L3 E phase-ground-loop: U L1 = Ι L1 ( R L + j X L )- Ι E ( R E +j X E ) Ι L1, Ι E U L1 measured current measured voltage The same applies to the remaining loops dtgerdis3

23 U t U j j e U e U U ω ϕ = = Impedance calculation using U- and I-phasors R Z I t I j j e I e I I ω ϕ = = I t I =ω ϕ U t U =ω ϕ = 0 t I U Z ϕ ϕ ϕ = ( ) X j R j Z e Z Z Z Z j Z + = + = = ϕ ϕ ϕ sin cos X ( ) ( ) ( ) I U I U j j j I U j I U e I U e I e U I U Z I U I U ϕ ϕ ϕ ϕ ϕ ϕ ϕ ϕ + = = = = sin cos R X

24 Numerical filtered phasor measurement X R 1. Fast operation Use short data window 2. High accuracy High selectivity 3. Signal distortion does not cause delay or maloperation

25 Fourier analysis of measured values sin 2 π n i Sampled measuring values i ( k n + i) i k-n n I S(k) k I C(k) Resulting phasor I (k) = I j I C(k) S(k) + j I C(k) I (k j ) cos 2 π n i ϕ I S(k)

26 Load and short-circuit impedances distance relay operating characteristic Z LF1 Z LF2 Z L X Fault area R F R F Z Load Z L D F1 F2 Z LF2 R R Z F2 Phase - Phase Fault Z Load R R R F / 2 Z LF1 R R Z F1 j L Phase - Earth Fault R R R F /(1 + R E /R L ) Fault in reverse direction j SC1 j SC2 R Load area Minimum Load Impedance: Minimum voltage 0,9 Un Maximum current 1,1 In Maximum angle ± 30

27 Impedance zones of digital relays X Line Z1B α Z1 Z2 Z4 Z5 Distance zones Inclined with line angle ϕ Angle α prevents overreach of Z1 on faults with fault resistance that are fed from both line ends Load ϕ Load Z3 R Fault detection no fault detection polygon: the largest zone determines the fault detection characteristic simple setting of load encroachment area with R min and ϕ Load

28 Graded distance zones t = grading time time Z 2 t 3 Z 3 Z 1 t 2 t 1 A B C D1 D2 D3 D Grading rules: Z 1 = 0,85 Z AB Z 2 = 0,85 (Z AB + 0,85 Z BC ) Z 3 = 0,85 (Z AB + 0,85 (Z BC + 0,85 Z CD )) distance Safety margin is 15 %: line error CT, VT error measuring error

29 Ring feeder: with grading against opposite end grading time (s) The same grading from both sides

30 Differential protection

31 Measuring Principle I 1 Lines and Cables I 5 Busbar Transformer I 2 Generator I 4 Motor I 3 Kirchhoff: I 1 +I 2 +I 3 +I 4 +I 5 =0

32 Line differential protection over 3 line ends 7SD52 7SD52 7SD52

33 No restrictions for communication Communication with direct FO connection up to 100 km digital communication network (G703, X21) ISDN-connection 2 or 3 wire pilot wire (twisted, screened) FO or 7SD5 O O E E Digital communication network or ISDN E E O O 7SD5 O E or 2/3 wire pilot wire (Cu) E O

34 Transformer differential protection S N = 100MVA I P1 = 500A (load current) U N1 = 110kV U N2 = 30kV 1000/5A 2000/5A I P2 = 1833A winding 1 winding 2 (load current) I N, Trafo = 525A I N, Trafo = 1924A I S1 = 2.5A I S2 = 4.58A 7UT512 measured secondary currents I Diff =? I Stab =?

35 Method of Vector Group Determination 2L1 2L2 2L3 Side 2: Side 1: 1L1 1L2 1L3 I L1,S2 = I L1 - I L2 I L1,S1 330 (n * 30 ) Vector group is Y d 11

36 Current transformer saturation Saturation during steady-state current Saturation during offset current

37 Trip Characteristic Idiff internal fault fault line (k=1) external fault or operation condition Ideal internal fault Idiff = I1 Istab = I1 fault is on fault line External fault Idiff = 0 Istab = I1 + I In security for CT deviations Istab

38 Busbar protection - summation transformer version X X X X ma Summation transformer 4AM5120

39 Distributed System substation 1,5 km 2. central unit fibre optics bay unit terminal panel terminal panel terminal panel terminal panel

40 Reliability of the protection relays X R 1. Fast operation Limit damages 2. High accuracy High selectivity 3. Signal distortion does not cause delay or malope

50 0-50 -100 0,995 1,000 1,005 1,010 1,015 1,020 1,025 1,030 1,035 1,040 1,045

CT saturation Non system frequent voltages with capacitive voltage transformers

frequencies with series compensation ZS MOV GAP -XC i/ka Power swings 6 3-3 u/kv

41 ,995 1,000 1,005 1,010 1,015 1,020 1,025 1,030 1,035 1,040 1,045 1,050 Power System Influences Inrush currents i 1 Transformer overexcitation t CT saturation Non system frequent voltages with capacitive voltage transformers U/V t/s X Leitung Variable system impedances with FACTS R Sub-synchronous frequencies with series compensation ZS MOV GAP -XC i/ka Power swings u/kv 500 t/ms t/ms Inter-area oscillations High equipment and route capacity utilization

Energy a core sector at Siemens

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