Electrodynamic tests of power transformers with reactive-power compensation

Abstract

It is shown that electrodynamic tests of power transformers are accompanied by the predominant consumption of a reactive power that is many times higher than the active-power consumption. A scheme of electrodynamic tests with longitudinal compensation of the reactive power using a capacitor bank is proposed. It allows a considerable reduction of the power that is consumed from the power-supply system. The parameters of the capacitor bank and the preliminary-charging voltage levels were determined that provide various current regimes for conducting both adjusting and actual short-circuiting experiments. The possibility of performing electrodynamic tests of power transformers with nominal powers of up to 630 MV A under the conditions of factory test centers using a controlled alternating-voltage source with a regulation range of 1.5–7.5 kV and a power of 22 MW was substantiated. Short-circuiting tests have a negative effect on the power-supply system because they are able to initiate a voltage dip with a duration of up to 0.2 s and even a dynamic-stability loss. As a result, the quality and reliability of electric-power supply of other consumers of the power-supply system deteriorate. The above negative consequences can be avoided and the required testing short-circuit current simultaneously provided via reduction of the total power consumed from the powersuppl system. In this study, the problem of the electromagnetic compatibility of an electrodynamic-test bench and a power-supply system is solved by compensating the reactive power during short-circuiting experiments.