Analysis on Response Characteristics of Control and Protection Systems in Event of Measurement Anomalies for UHVDC Transmission System

The measurement system in UHVDC systems mainly includes DC voltage measurement and DC current measurement, and the accuracy of its results is the key to ensure the reliable operation of the DC control and protection systems. In this paper, based on the analysis of the principle of the UHVDC transmission system, the +/- 800kV UHVDC transmission system model is constructed using PSCAD/EMTDC simulation software. The effects of rectifier-side DC current and DC voltage measurement faults on the response characteristics of the DC control and protection systems are investigated under different scenarios by superimposing different abnormal measurement values, and the simulation results are analyzed in conjunction with the control strategy and protection principles. The simulation results show that the DC system exhibits different response characteristics under different measurement anomalies. The deviation of rectifier-side DC current measurement affects the DC voltage, DC current and power transmission of the two stations and causes the protections to operate. And the abnormal DC voltage measurement causes the protections to operate falsely.