Investigation For Electromagnetic Disturbance Characteristics Of UPFC Converter Valve And Electromagnetic Shielding Effectiveness Of Valve Hall

Unified Power Flow Controller(UPFC)is the most advanced flexible Alternating Current transmission device.Based on the Modular Multilevel Converter(MMC),a large number of insulated gate bipolar transistors(IGBT)are used on the converter valve to implement the commutation function.During the normal operation of the converter valve,IGBT is turned on and off periodically.When it is turned on or off,it always causes a sharp change of voltage and current at both ends which results in a large amount of electromagnetic disturbance.There are usually secondary equipment rooms,main control rooms and other places where low-voltage power electronic devices and equipment are placed around the UPFC valve hall.Workers also patrol and work around the valve hall.If no electromagnetic measures are taken on the valve hall,this part of electromagnetic disturbance not only may cause the equipment to malfunction or refuse to move,but also may exceed the human electromagnetic environment control limits.Therefore,it is necessary to study the electromagnetic disturbance which is generated by the converter valve and the shielding effectiveness of the valve hall.This paper is based on an UPFC project in Suzhou.Firstly,this paper establishes the prediction calculation model of the electromagnetic radiation of the UPFC converter valve which is based on the dipole radiation theory and superposition principle,combined with the signal processing principle of the radio disturbance test equipment.The distribution characteristics of the space electromagnetic field in the valve hall is calculated and analyzed.Then we measure the electromagnetic field distribution characteristic of the internal space of the UPFC valve hall.Combined with the calculation results and the relevant electromagnetic environment control limits,we propose the shielding effectiveness requirement of the UPFC valve hall is 30dB.And then shielding effectiveness of the valve hall for the actual steel structure is measured.The results show that the shielding effectiveness of the valve hall is greater than 50dB,which is higher than the shielding requirements of the UPFC valve hall.Finally,the electromagnetic shielding design scheme of the UPFC valve hall is given for the shielding effectiveness requirements of 40dB,30dB and 20dB respectively.This study has reference value for the actual UPFC station electromagnetic compatibility design and electromagnetic shielding design.