Renewable Energy Systems Integration (RESI)
S2, 2025
Part 2 Tutorial
Q.1
Figure 1 shows the schematic diagram of a three-phase wind plant installed in a Micro Grid to feed a utility grid. The wind plant is connected at Bus 1 and is with six identical fixed-speed wind turbine (induction) generators. Each wind turbine generator is rated at 50Hz, 690V, 710 KVA.
Figure 1
Table 1 gives the parameters of wind turbine generators in the wind plant referred to the stator in Ω/phase.
Table 1
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Stator resistance
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0.00510
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Stator reactance
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0.06820
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Rotor resistance
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0.01340
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Rotor reactance
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0.09200
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Magnetizing reactance
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2.78400
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The wind plant connects the feeder between Bus 2 and Bus 3 via a 5 MVA, 0.69/11 kV transformer. The transformer has a leakage reactance of 0.062 pu. The real power loss of the transformer is negligible. Table 2 gives the parameters of the feeder between Bus 2 and Bus 3. The entire system operates at 50Hz. Consider the slip of an induction generator as -0.0185:
Table 2
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Length
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10 km
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Rated voltage
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11 kV
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Thermal rating
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10MVA
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Resistance
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0.4 Ω/ km/ phase
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Reactance
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0.44 Ω / km/ phase
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(a) Calculate at full load and no load power generated and consumed by wind turbine generators.
(b) Calculate no load and full load voltage at Bus 1.
Q.2
If the system given in Figure 1 is connected with a capacitor bank, as shown in Figure 2, for the correction of power factor:
Figure 2
(a) Calculate the required capacitance at Bus 1 to reduce the no load current of induction generators to zero.
(b) Calculate the voltage at Bus 1 with the calculated capacitor bank in (a)
Q.3
Calculate the full load active and reactive power losses of the system shown in Figure 2 with the capacitor bank size calculated in 2(a) and without. Ignore the losses of the terminals of wind turbine generators.