Simulation Research on Circuit Power and Harmonics of DC Bias Injection Test Device

Taking a ±800kV UHV DC project as an example, DC bias testing should be carried out before the project is put into operation to investigate the impact of single pole operation on the equipment of nearby substations. In order to ensure the smooth implementation of the DC bias test, a study on the DC bias injection test method was carried out, and a high-capacity DC bias injection test circuit was designed to simulate the generation process of DC current, estimate the output current, analyze the harmonic characteristics of output current and voltage, and analyze the impact of AC side harmonics on the power grid. A simulation model was established in the simulink simulation platform to complete the simulation study of equipment power and harmonics.