A Novel Simulation Method for the Zero-flux Current Transformer in the HVDC Systems Based on Magnetic Path and Electrical Circuit

In the high voltage direct current (HVDC) systems, the measurement of DC current is very important for monitoring HVDC control and protection purposes. The zero-flux current transformer is a good choice to detect the currents of the DC neutral bus and the DC pole line. However, the magnetic head of DCCT is a three-dimensional structure with multiple cores and multiple windings. The circumference of the core is several hundred times larger than its cross-sectional size. Therefore, it is difficult to perform electromagnetic simulation through finite element analysis. In this paper, a novel simulation method for the zero-flux current transformer based on magnetic path and electrical circuit is proposed. This makes it possible to conduct simulation calculations for large-sized zero-flux current transformers.