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Keywords

extra high voltage, overhead-cable hybrid lines, closing overvoltage, closing resistance

Abstract

With the development of city and its power supply demand increase, the overhead-cable hybrid line have become more and more widely application due to its flexible structure. The overvoltage caused by the closing operation of the hybrid line has become an important factor affecting the safe and reliable operation of the power system. In this paper, PSCAD simulation software is employed to study the closing overvoltage characteristics of 220 kV extra high voltage (EHV) overhead-cable hybrid lines in a certain area. An overvoltage simulation model is established, and the closing overvoltage characteristics generated during the closing operation of the hybrid line are simulated and analyzed. Finally, the affecting factors of the closing overvoltage are discussed. The results show that, the overvoltage amplitude of three-phase non-synchronous closing is 10%~20% larger than that of three-phase synchronous closing. The closing overvoltage is related to the closing phase angle, and the closing overvoltage amplitude is inversely proportional to the closing resistance. Through the coordination of the closing time, the closing resistors are input in stages to release energy systematically. Thereby, it is found that the application of multi-level closing resistance can limit the operating overvoltage more effectively. The proposed research provides a reference for the design of EHV overhead-cable hybrid line.

DOI

10.19781/j.issn.1673-9140.2022.01.021

First Page

178

Last Page

185

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