Combined resonance eliminating device suitable for 4PT

The invention discloses a combined resonance eliminating device suitable for a 4PT. The combined resonance eliminating device comprises a three-phase voltage transformer, a zero-sequence voltage transformer, a controllable switch KA and a microcomputer resonance eliminating device body. The primary side of the three-phase voltage transformer is in a star shape through connection, and the neutral point of the star shape is grounded through the primary side of the zero-sequence voltage transformer. The secondary side of the three-phase voltage transformer comprises a first winding and a second winding, one end of a triangular opening of the first winding of the secondary side is connected with the end 0 of the controllable switch KA, the other end of the opening is connected with the end 2 of the controllable switch KA, the second winding of the secondary side is in a star shape through connection, and the neutral point of the star shape is grounded through the secondary side of the zero-sequence voltage transformer. The microcomputer resonance eliminating device collects the voltage of the secondary side of the zero-sequence voltage transformer, and the power resistance output end is connected with the end 1 and the end 2 of the controllable switch KA and outputs a control signal of the controllable switch KA at the same time. The combined resonance eliminating device suitable for the 4PT is simple in structure, easy to control and capable of eliminating resonance of an ultra-low-frequency transformer.