Abstract: This paper is based on the difference in the layout of the primary equipment of the voltage mutual inductor during the construction and commissioning of a thermal power plant, which leads to the opposite phase sequence, the opposite phase of the primary voltage and the secondary voltage, the wrong use of the secondary winding of the current mutual inductor with different accuracy levels, and the wrong wiring of the corresponding load of different zero-sequence current mutual inductors. The method of comparing the difference between the factory drawing and the design institute drawing, standardizating the secondary circuit wiring, checking the voltage and current transient and steady-state amplitude phase after the equipment is charged, comparing the DC resistance value and voltammeter characteristic parameters and other construction considerations and acceptance are put forward, which effectively ensures the correctness of the circuit wiring.

    Key words: mutual inductor; secondary winding; arrangement order; DC resistance