基于注入信号法的容性设备介质损耗在线测量系统

On-line Measurement System of Dielectric Loss Tangent for Capacitive Apparatus Based on the Injecting Signal Method

针对介质损耗(简称介损)测量在准确度和抗干扰等方面的不足,介绍了一种基于注入信号法的介损在线高精度测量系统。该测量系统采用FPGA产生可变频的注入信号,然后利用注入信号进行系统自校正和产生介损测量信号,再结合双极性过零比较法和信号拟合技术进行介损计算。测试结果表明,该系统可有效削弱电网工频干扰和消除装置的固有测量误差,使介损在线测量的准确性和稳定性显著提高。

In order to improve the precision and anti-interference capacity of on-line tan δ monitoring system for capacitive apparatus, a high precision tan δ monitoring system is presented. The injecting signal produced by FPGA is used to realize the functions such as error adaptive correcting and the signal producing for measurement of dielectric loss. Then the tan δ is calculated by combining the integrated techniques of signals with the zero cross point comparing method. The results of experiment and field tests show that the interference of power system in power frequency can be avoided and also the inherent measuring errors of hardware can be eliminated. Thus the precision and stability of this system proposed are verified much better than those of the traditional measuring equipment.