CALCULATIONS FOR SHORT CIRCUIT WITHSTAND CAPABILITY OF A DISTRIBUTION TRANSFORMER
The short circuit withstand test is the only test which is not performed in the manufacturers test laboratory. There is a need for a high test field power, especially for large units with ratings of 100MVA and above. The tests can only be performed at a few powerful test stations, such as those operated in KEMA (Netherlands), EDF (France), CESI (Italy) or IREQ (Canada). Short circuit tests are expensive. Not only is the cost of the test itself high, but also activities such as transport to and from the factory, local installation at the test laboratory and again at the factory , untanking and inspection , repetition of dielectic tests etc. For this reason the IEC standards also permits demonstration of the short circuit ability using calculation and design considerations. In this paper the different parameters for short circuit withstand capability is calculated for a 1500KVA, 22KV/415V, Dyn11 Distribution Transformer.