TESTING METHOD OF TEMPERATURE RISE OF TRANSFORMER

摘要

PURPOSE:To execute a temperature rise test by using a tap-difference conversion load method in a state close to a rated voltage and a rated current by a method wherein, when a required circulating current cannot be obtained, a dummy load is connected to secondary sides of transformers which are operated in parallel and a secondary-side circulating current flowing in a transformer under test is superposed on a dummy load current effectively. CONSTITUTION:When a difference voltage (e) which circulates a required secondary-side circulating current 12 cannot be obtained, a dummy load XC is connected to secondary sides of transformers TL, TR which are operated in parallel. When output voltages E2 at the secondary sides are used as a reference vector, the vector of the circulating current I2 flowing in the transformer TL is advanced by nearly 90 deg. from an output voltage E2, and the vector of the circulating current I2 flowing in the transformer TR is delayed by nearly 90 deg. from the output voltage E2. A dummy load current I2CL of the circulating current I2 flowing in the transformer TL show a nearly identical phase; a dummy load current I2CR of the circulating current I2 flowing in the transformer TR show a nearly opposite phase. Thereby, the dummy load currents I2CL and I2CR are superposed on the circulating currents I2 flowing in the transformer T1 and TR. A lack of the circulating current flowing in the transformer TL under test can be supplemented by the dummy load current I2CL.