电容型设备绝缘在线监测信号采集方式的实践

The Practice of Insulating Signal Collection Method of Capacitive Equipment Online Monitoring

电容型设备介质损耗在线监测,每台被试设备配一只磁性耦合传感器,采样输出信号弱,传感器本身和信号传输电缆易受电磁干扰,不同地点受干扰的程度不同,在加上每个传感器角差的差异,往往同类同相介质损相近的被试设备的测量结果差别很大。为此,提出采用被试品末屏串接保护单元通过大容量的可控硅来控制测试通道通断的带电测试方法,能把磁性耦合传感器移到测试仪器内,实现所有的被试品使用同一传感器和统一的通道测试,不仅可用绝对值法测试,还可用相对比较法测试,降低了几个干扰因素的影响。采用该方法在现场大量的测试数值表明可信、可比、稳定,能有效地判断电容型设备的绝缘状况。

Each online monitoring equipment of dielectric loss factor devices is equipped with a magnetic coupling sensor. Its sampling output signal is weak and is likely to be effected by electromagnetic interference, and the angle error of each sensor is different. All these factors result in the great difference of measuring results of similar capacitive equipments. Therefore the online monitoring method is brought up that the tap of detected equipment is connected with a protection unit in series and the detection channel is controlled by high power thyristor. The magnetic coupling sensor is installed in the detection equipment, hence all detected equipment are detected through the same sensor and the same channel. Absolute value model or relative comparison method can be used. The method reduces influence of several interference factors. The practice of this method in the field shows its stability and reliability. The insulation condition of capacitive equipment can be diagnosed effectively by using this method.