基于扫频法配电网电容电流测量装置研制  

Development of capacitive current measuring instrument based on frequency scanning method for power distribution system

作　　者：严干贵[1] 李果雪[1] 张正茂[1] 肖龙章 曹军[2] 穆钢[1] 戴武昌[1] 

机构地区：[1]东北电力大学电气工程学院,吉林吉林132012 [2]吉林供电公司,吉林吉林132001

出　　处：《电力自动化设备》2007年第3期64-68,共5页Electric Power Automation Equipment

摘　　要：准确测量配电网对地电容电流是确定消弧补偿及其容量的重要依据,为此研制了基于扫频法配电网电容电流测量装置,其工作原理是在消弧线圈电压互感器(TV)二次侧注入一方波变频电压,通过检测TV二次侧电流与所注入电压是否同相位来确定配电网对地电容与消弧线圈电感的并联谐振频率,进而求出对地电容电流。该装置由扫频信号发生源和控制器组成,其中扫频信号发生源是基于IGBT、直流侧电压为300 V的单相逆变器,用于向系统注入一方波变频电压;控制器采用混合信号片上系统(SoC)——C8051F 020单片机,用于产生递增变频控制信号,该控制信号经光耦隔离、放大电路驱动,以控制IGBT通断。利用EMTDC/PSCAD仿真和物理试验,对装置有效性进行验证,结果表明装置测量误差小于2%。Accurate capacitive current measurement is the basis of arc- suppression compensation capacity determination. A measuring instrument based on frequency scanning method for power distribution system is developed. Square- wave voltages with various frequencies are injected to the secondary side of the PT （Potential Transformer）of arc suppression coil,the parallel-resonance frequency between the parallel- connected suppression coil inductor and the grounding capacitor can thus be determined by detecting if the current at the secondary side of PT is in phase of the injected voltage,and the grounding capacitive current is further deduced. The instrument consists of a scanning frequency generator and a controller. The former is an IGBT- based single- phase inverter with DC side voltage being 300 V,which generates square- wave voltages with various frequencies.The latter uses a SoC （System- on- Chip） C 8051F020 to generate an increasing- frequency control signal to control the on- off of IGBT via optical coupling isolation and amplification. Simulations with EMTDC/PSCAD and physical experiments prove the measurement error is less than 2 %.

关 键 词：配电网 扫频法 电容电流 单相逆变器 测量装置 

分 类 号：TM934.2[电气工程—电力电子与电力传动]