1. Electric Power Research Institute of State Grid Zhejiang Electric Power Co., Ltd., Hangzhou 310014, China;2. College of Electrical Engineering, Zhejiang University, Hangzhou 310027, China;3. College of Electrical Engineering, Sichuan University, Chengdu 610065, China
The ultra-high voltage direct current(UHVDC)converter station is usually equipped with multiple sets of AC filters, which can filter the characteristic harmonics and compensate for the reactive power. However, the AC filters are easy to interact with the background harmonic impedance of power grid to cause low-order harmonic amplification. The background harmonic impedance of AC power grid is the foundation of harmonic characteristic analysis and AC filter design. According to the fact that the characteristics of background harmonic impedance of power grid are complex and it is hard to be calculated by modelling, this paper proposes an estimation method of background harmonic impedance of 500 kV AC power grid based on different operation conditions of the converter station. Then, the harmonic gain index of the AC filter sets is defined. Through this index, the amplification mechanism of the low-order harmonics by the AC filter sets in the UHVDC converter station is analyzed. The relationship between the amplification and the parameters of AC filter is studied, and two modification schemes for AC filters are proposed. Finally, taking the measured data of Shaoxing converter station as an example, and considering the estimation results of background harmonic impedance of power grid, the 5th harmonic amplification problem is theoretically analyzed, while the modification schemes for AC filters are discussed.
LYU Wentao, XIE Haiwei, XU Qunwei,et al.Analysis on Impact of AC Filter Sets on Power Grid Harmonic in UHVDC Converter Station[J].Automation of Electric Power Systems,2019,43(23):217-225.DOI:10.7500/AEPS20190201002Copy