Study on models of the HVDC converter for calculation of high-frequency interference

High-frequency noise in HVDC converter station is mainly generated by converter valves. As the basic unit of the converter, the model of 12-pulse bridge has a direct impact on calculation of high-frequency interference in HVDC station. Based on the traditional model of noise source, voltage-divide model of 12-pulse bridge is put forward with 3-pulse bridge as the basic unit of high-frequency noise generation. The voltage waveforms of some positions are simulated in PSCAD/EMTDC and the noise spectra are obtained by FFT analysis to verify the validity of the voltage-divide model. The voltage-divide model proves to be able to simulate the distribution of the noise voltage inside 12-pulse bridge. Take GUI-GUANG project in China as an example, interference noise using the two models are calculated at AC side of the HVDC project. It is proved that the result from voltage-divider model is more accurate than that from traditional one through comparison between reference noise curve and calculated noise curve.