基于变频信号法的一种对地电容电流检测系统-电力系统保护与控制.PDFVIP

第42 卷 第23 期 电力系统保护与控制 Vol.42 No.23 2014 年 12 月 1 日 Power System Protection and Control Dec. 1, 2014 基于变频信号法的一种对地电容电流检测系统 林 凌，刘明光 （北京交通大学电气工程学院，北京 100044 ） 摘要：现有的基于变频信号法的对地电容电流检测系统多采用PWM 逆变的方式作为扫频信号源，在应用中受到较多制约。对 对地电容电流检测系统进行重新设计，检测系统的测量单元采用双单片机模式，信号源部分使用单片机控制 DAC 芯片作为数 控信号源，经模拟实验验证在该应用中其性能优于传统的 PWM 逆变方式扫频信号源。相位测量部分由 C8051F20 片上系统兼 顾相位检测与通信功能，上位机软件基于 C/S 构架搭建。该检测系统测量一次电容电流的时间不超过 10 s，经现场实验验 证了样机的测量误差在±2%以内，可直接应用于中压配电网的预调式消弧线圈，进一步设计后可应用于随调试消弧线圈。 关键词：对地电容电流；消弧线圈；变频信号法；双单片机系统；系统通信 A capacitive current detecting system based on variable frequency method LIN Ling, LIU Ming-guang (School of Electrical Engineering, Beijing Jiaotong University, Beijing 100044, China) Abstract: The existing line-to-earth capacitive current detecting system based on variable frequency method uses PWM inverter as variable frequency source, which has many constraints in practical use. This paper redesigns the detecting system. Each measure unit is constructed with double single-chip computer model and uses single-chip to control the DAC chip as the variable frequency source. The model experiment proves that the DAC type variable frequency source has better performance than the source based on PWM inverter. The system-on-chip of C8051F20 is in charge of the phase detection and communication function. The build of upper computer software is based on the C/S architecture. This detection system can detect the capacitive current within 10 seconds and the field experiment proves that the measuring error is under ±2%. This system can be directly applied to the preset ar