Wide Frequency Model Of Valve System And Research On Electric Magnetic Disturbance Characteristic In High Voltage Direct Current Converter Station

Understanding the electromagnetic compatibility (EMC) circumstance of±500kV High Voltage Direct Current (HVDC) converter station, modeling and predicting calculation independently, establishing the foundation of the EMC design of higher voltage class are the requirements of localization of HVDC technology. In this thesis supported by the Scientific Funds for Outstanding Young Scientists of China (No. 50325723), Project Supported by National Science of China(NSFC No.50707008), and Project Supported by National Development and Reform Commission (NDRC No. EHV[2007]GC004), measurements have been made of the electromagnetic disturbance (EMS) in three±500kV HVDC converter stations,and the time- frequency characteristic of the EMS are acquired. Based on the measurement, the Time Domain finite Element (TDFE) method for passive modeling of transmission lines and the wide band topology model of HVDC converter station are emphatically researched. Based on this model the primary conduct and radiation disturbance and the radio interference around the converter station are calculated. Compared with the measuring results, the proposed methods are proved to be correct. The main innovative achievements are as follows:1. Acquired the EMD characteristic of±500kV HVDC converter station when the converter station is normal running or the switch is operated. These measured results enriched the data base of HVDC converter station EMD circumstance in China.2. An effective method (TDFE) is presented for the analysis of transient response of Multi conductor lines (MTLs) with lumped parameter network. This method overcomes the disadvantage of FDTD, which is difficult to solve the MTLs with lumped parameter network branches. Further more the TDFE can effectively suppress the oscillation which is generated using FDTD method. At last the method is applied to numerical prediction of the EMD in secondary cable and the earth current of converter station generated by switching transient current through CVT.3. The paper presents converter the one-port elements to the form of dual-port network, and then measure the scattering parameter by network analyzer. Based on the scattering parameter this paper modeled the wide frequency circuit of valve elements in HVDC with Brune synthesis method. By comparing the measured results with EMTP simulation ensure the efficiency and accuracy of the model.4. The wide band topology model of±500kV HVDC converter station is set up. On the base of the wide band model, the conduct and radiation disturbance generated by primary system when the converter station is normal running are predicted. Compared with the measuring results, the model is proved to be efficiency. At last the model is applied to the research of the conduct and radiation disturbance problem when the converter station is normal running.5. Taking the transients voltage which is generated by the thyristor cut-on as driving source, the radio interference level around the HVDC converter station is numerical predicted.