Method and system for online measurement of short-circuit loss and open-circuit loss of transformer

The invention belongs to the technical field of a power system, and particularly discloses a method for online measurement of short-circuit loss and open-circuit loss of a transformer. The method is based on the measurement principle that firstly short-circuit impedance of the transformer is calculated by utilizing the voltage and the current of the primary side and secondary side of the transformer, and then the short-circuit loss and open-circuit loss is calculated by utilizing the short-circuit impedance. According the property that the primary side voltage during normal operation of the transformer almost does not change with loads, an ideal AC constant-voltage source is used to substitute the primary side voltage of the transformer. Then a data collection device is adopted to collect a primary side current signal and secondary side voltage and current signals of the transformer; and the collected voltage and current signals as well as the constant-voltage source signals are processed by certain numerical calculation, and linear fitting is used to achieve the online short-circuit impedance measurement. Finally, the short-circuit loss and open-circuit loss of the transformer are calculated by utilizing the measured short-circuit impedance. The measurement method can save a great amount of manpower and material resources, and does not affect the continuity of power supply.