Time-domain Simulation of Conducted EMD Caused by HVDC Valves in Substations

The wide-band frequency electromagnetic noise is generated by periodical turn-on and turn-off processes of thyristor valves in converter stations. It will be conducted along the primary circuit, and may interfere with secondary systems such as power line carrier (PLC) systems, measuring systems and so on. A simulation method to analyze the conducted electromagnetic disturbance (EMD) based on time-domain wide-band equivalent circuits was proposed in the paper. The steady-state electromagnetic process and EMD were calculated together. Influences of operating states and device characteristics on EMD generation and propagation, can be easily considered. Models of mayor equipments such as converters, converter transformers, smoothing reactors, were described. The EMD source from valves was simulated by a macro-model, and other devices were represented by wide-band equivalent models considering working frequency and high frequency characteristics. Parameters of these models can be derived from significations and test results provided by manufacturers. The method was verified by field test results in a ±500 kV converter station, and the EMD levels of a ±500 kV transmission project called Guizhou-Guangzhou II were calculated by the method.