电容式电压互感器传变特性研究  

Research of CVT Transient Response

作　　者：黄然 周仿荣 张恭源 赵现平 

机构地区：[1]云南电网电力研究院,昆明650217

出　　处：《高压电器》2015年第8期158-163,共6页High Voltage Apparatus

摘　　要：电容式电压互感器存在电磁单元,当过电压达一定值时,中间变压器及速饱和电抗器可能饱和,在低频振荡下CVT的分压比降低,二次绕组测量到的电压值将高于实际值,导致过压保护误动。文中以500 k V多乐永丰I回线在带高抗切除空线时过压保护动作为切入点,通过过电压电磁暂态仿真及CVT在系统电压偏离工频时的传变特性计算,分析CVT在低频饱和状态下二次侧测量电压被放大的原因,研究CVT饱和后的电压测量偏差。该线路空载分闸过电压现场测试数据,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。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.

关 键 词：过电压 CVT 传变特性 饱和 低频振荡 仿真 实测 

分 类 号：TM451.2[电气工程—电器]