Current Contribution from Wind Plant for a System Fault

Working Group C17

May 2010 Meeting

Details• 67 Suzlons S88 2.1MW wind turbine-

generator

• 61 turbine-generators sync. to the system before the fault

• B ph to gnd fault on 138kV tie line to wind plant occurred at 22:40 11/25/2009

Suzlons S88 2.1MW wind turbine-generator

• A type 2 wound rotor induction generator with variable rotor resistance

System One Line

138 kV

Total line length11.9 miles

To Canyon Compression/

Naughton

ToLong Hollow

MUDDY CREEK

143

133

Collector Circuits34.5kV

34.5kV

Fault location mileageFrom Muddy Crk

8.6 miles

MOUNTAIN WIND

9 Turbine Generators

10 Turbine Generators

10 Turbine Generators

9 Turbine Generators

9 Turbine Generators

10 Turbine Generators

10 Turbine Generators

Status at Wind Plant before the

Fault

61 machines sync to system

14.6MW total output

11.4% of nameplate

Mountain Wind Sub 11A relay on line to Muddy Creek

Muddy Creek Sub 11A relay on line to Mountain Wind

Mountain Wind Sub (Wind Plant) Positive Sequence Current

Muddy Creek Sub (System) Positive Sequence Current

Generator Impedance

Generator Data

Using the Asynchronous Generator Values

Xs = 0.0536

Xm = 2.6

Xr = 0.0564

X’ = 0.1088 ohms

Synchronous data

X” = 0.0523 ohms

X’ = 0.0941 ohms

Generator Step up Transformer

Z = 5.75 % @ 2.25MVA

Filtered Fault Data

Phasor Data

Comparison of ResultsB Phase I1 I2 I0 I1 + I2 + I0

Measured

Time 1 1.1 cycle 1908 398 297 1092 1786

Time 2 1.9 cycle 1850 330 420 1096 1812

Time 3 3.0 cycle 1650 230 379 963 1535

Time Fault Interrupted 4.1 cycles

Fault Study

Subtransient 1786 396 346 1044 1786

Transient (equivalent synchronous) 1713 343 341 1029 1713

Transient (equivalent asynchronous) 1692 327 339 1025 1692

Faulted phase voltage on closest generator's terminals 0.82 pu

Conclusion

• For relay performance the subtransient reactance using the equivalent synchronous data provides the best fault current values

• For breaker interrupting currents the transient reactance using the calculated value from the equivalent asynchronous data provides the best fault current values