HUANG Ran, ZHOU Fangrong, ZHANG Gongyuan, et al. Research of CVT Transient Response[J]. High voltageapparatus, 2015, 51(8): 158-163. DOI: 10.13296/j.1001-1609.hva.2015.08.027.
充分验证了CVT低频下传变特性改变引起测量值大于实际值是500 k V多永I回线在空载分闸时过压保护动作的真正原因。
Abstract
When the over-voltage of power-grid reaches a certain value
the reactor of CVT may be saturated within a very short time; thus the voltage ratio of CVT is reduced under the condition of low frequency oscillation. In this paper
the action of over-voltage protection of the 500 k V Duole-Yongfeng No. 1 transmission line is analyzed to find out the reason why secondary side voltage of CVT is amplified in such circumstance. Simulation of overvoltage and calculation of transfer characteristics of CVT with voltage deviating from the power frequency are conducted to determine the deviation of voltage measurement of the saturated CVT. It is concluded that the action of over-voltage protection of the 500 k V Duole-Yongfeng No. 1 transmission line is due to the change of transfer characteristics of CVT
which results in an amplification of the voltage measurement under the working condition of low-frequency saturated over-voltage. Field test demonstrates that the analysis in this paper is correct.