List the conditions for parallel operation of three phase transformer.

List the conditions for parallel operation of three phase transformer.

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Conditions for Parallel operation of 3 phase transformer: 1) Voltage ratings of both the transformers must be identical. 2) Percentage / p.u. impedances should be equal in magnitude. 3) X/R ratio of the transformer windings should be equal. 4) Transformer terminals with identical polarity must be connected to each other on secondary side. 5) Phase displacement between primary & secondary voltages must be same. 6) Phase sequence of both must be same.

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Why phasing out and polarity test is carried out on three phase transformer?

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A three-phase transformer, connected in star-delta, is composed of three single-phase transformers, each

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Three phase step-up transformer installed at power house, just before commencement of transmission line, have:

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Last Answer : Answer: A