短时能量分析法在断路器机械状态监测中的应用

Application of Short-Time Energy Analysis in Condition Monitoring of Circuit Breakers

针对断路器机械特性在线监测中触头关合时刻难以获取的缺点 ,研究了短时能量法在断路器机械振动信号分析中的应用 .通过定量分析指出 ,短时能量法的优点在于有效提高了信噪比 ,可以从现场复杂的噪声环境中提取出振动事件的起始时间 .试验中将该方法应用于ZN12 35型真空断路器的合闸振动信号分析 ,准确得到了空载情况下三相触头的闭合时刻 ,从而计算出不同机械状态下的合闸同期性与合闸时间等状态参数 .在关合单相短路电流的情况下测试了VS1 12型真空断路器的合闸振动信号 ,分析了不同短路电流对振动信号测量及合闸同期性的影响 ,进一步验证了短时能量分析法的有效性和准确性 .试验结果表明 ,在选择合适的窗函数的基础上 ,短时能量分析法的测量精度能达到 0 2ms .

To avoid the drawback that the closing moment of circuit breakers are difficult to measure in online condition monitoring, the application of short-time energy (STE) analysis in the event time detection of the vibration signal was investigated. The quantitative analysis shows that STE method can significantly improve the signal-to-noise ratio (SNR), which facilitates determining the commencement of the vibration event from an adverse environment. This approach was applied to a ZN12-35 type vacuum circuit breaker for analyzing the vibration signals during the closing operation. The closing moments of three poles were gained accurately by STE analysis, and some mechanical parameters such as closing-simultaneity and closing time were calculated correctly. Moreover, a VS1-12 type vacuum circuit breaker was tested via analyzing the vibration signals under the condition of the single pole short-circuit current. The influences of different peak currents on the measurement system and closing simultaneity of the circuit breaker were discussed. The test results show that STE analysis has a measurement accuracy of 0.2 ms after selecting a proper window function.