A pilot directional protection based on low frequency voltage variable quantity for LCC-HVDC transmission lines

• Published in: International journal of electrical power & energy systems Vol. 145; p. 108512
• Main Authors: Chen, Yu, Wen, Minghao, Wang, Zhen, Yin, Xianggen
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.02.2023
• Subjects: LCC-HVDC; Low-frequency voltage; Pilot directional protection; Transmission lines; Variable quantity; Transmission lines; Pilot directional protection; Low-frequency voltage; Variable quantity; LCC-HVDC
• ISSN: 0142-0615
• DOI: 10.1016/j.ijepes.2022.108512

•The fault direction can be identified by comparing the voltage variable quantity.•The pilot directional protection has high sensitivity and high security.•The proposed pilot directional protection requires the low sampling frequency. In this paper, a pilot directional protection based on low frequency voltage variable quantities for LCC-HVDC transmission lines is proposed. Based on the regularities of low frequency voltage distribution along the HVDC transmission line, the low frequency voltage variable quantities of the positive pole and negative pole are defined. Then, the theory of low frequency voltage variable quantities based directional protection is presented. The low frequency voltage variable quantity variation characteristics of the relay device location point and calculation point under different fault conditions are analyzed. If a forward fault occurs, the low frequency voltage variable quantity of the calculation point would be larger than that of relay device location point. If a reverse fault occurs, the low frequency voltage variable quantity of the calculation point will be less than that of relay device location point. Next, the criteria of the low frequency voltage variable quantity based pilot directional protection is proposed. Finally, an LCC-HVDC transmission system is modelled for simulation. Simulation results reveal that the presented pilot directional protection has obvious physical significance with simple calculation and is adaptive to lower sampling frequency. Besides, the presented algorithm is independent on the HVDC transmission line boundary and invulnerable to strong noise and high fault resistance.