无间隙金属氧化物避雷器运行状态特征参数温度特性研究

The Study on Temperature Character of Operating State Parameter of Metal Oxide Surge Arrester without Gaps in Service

无间隙金属氧化物避雷器(MOA)的运行状态监测是保证电力系统可靠运行的重要措施,由于MOA运行状态参量受环境温度影响,会造成对MOA状态判断不准确,引发严重事故。研究了MOA运行状态主要监测参量随温度的变化特性,揭示了状态参量变化与温度、荷电率及电阻片几何尺寸的关系。持续运行电压下,在20℃～60℃范围内,直流U1mA、工频参考电压随温度单调递减,交流泄漏单调递增;全泄漏电流具有微弱的正温度系数,随温度的升高而缓慢递增,而阻性电流分量随温度变化增长更快。在80%～90%荷电率下运行,MOA的阻性电流IR、功率损耗P随温度的升高和荷电率的增大单调快速递增。

Supervising the operating state of metal oxide arrester （MOA） is very important measure to ensure stabilization and safety of power system. Because the ambient temperature affects the operating state parameters of MOA, it may result in the diagnostic mistake and fault. The author studies the dependence of the detected state parameters of MOA with temperature. It is analyzed that the varying character of the operating state parameters of MOA on the temperature, load rate and dimensions of ZnO resistor. Under the continuous operating voltage, at 20 ℃-60℃ , U1mA DC and U1mA A C are monotonously decreasing with temperature; while the AC leakage current, having slight positive temperature monotonously. The joint leakage current, having slight positive temperature coefficient, increases slowly with the temperature rise, while resistive leak current increases even faster. Continuous current of MOA is of a faint positive-temperature coefficient. Operating at electric stress ratio of 80% - 90%, the resistive leakage current IR are power loss P fast monotonously increase with temperature rise and enhancement of electric stress ratio.