Method for configuring station transformer over-excitation protection of extra-high voltage convertor station

Abstract

The invention relates to a method for configuring station transformer over-excitation protection of an extra-high voltage convertor station, wherein the voltage level of the extra-high voltage convertor station is 500kV, a GIS device is applied to a station transformer circuit, a voltage transformer for the station transformer circuit is not used, and the station transformer and the GIS device are in GIL connection; and the extra-high voltage convertor station is divided into feeding end and receiving end convertor stations, wherein the work frequency steady state overvoltage level of an alternating current system of the receiving end converter station is not less than 1.1p.u, and the highest working magnetic flux density of the station transformer is 1.65-1.75T and is lower than saturation magnetic flux density which is 1.8-2T. According to the method disclosed by the invention, the 500kV station transformer of the extra-high voltage convertor station can run for a long term without over-excitation protection when the steady overvoltage level of the system is not less than 1.1p.u, and the circuit voltage transformer is not needed; therefore, engineering investment is saved, the total level arrangement is optimized, and an excellent base is provided for popularization and application of the GIL connection manner in the transformer circuit of the extra-high voltage convertor station.

Description

technical field [0001] The invention relates to a method for configuring over-excitation protection of a transformer used in a 500kV substation of an ultra-high voltage converter station. Background technique [0002] DC transmission is mainly used in long-distance high-power transmission and networking of asynchronous AC systems. The converter station is the core of the DC transmission system and completes the conversion between AC and DC. The ±800kV converter station is currently the converter station with the highest voltage level in China. The power consumption of the station is generally considered to be connected to 2 times the station power supply inside the station, and 1 times the station power supply to be connected outside the station. The 2 station power supplies in the station are connected to the AC GIS equipment in the station, the voltage level is 500kV, two station transformers are installed, and the voltage level of the low voltage side is 10kV. [0003] T...

AI Technical Summary

Problems solved by technology

[0005] At present, the transformer circuit of the UHV converter station generally adopts AIS equipment and is connected by an overhead line, which occupies a large area and is not conducive to the overall layout of the converter station