光伏阵列对地绝缘阻抗检测电路及检测方法研究  

Research on Detection Circuit and Method of Ground Insulation Impedance for Photovoltaic Array

作　　者：李炅 姜利 宁光富 吴晋波 何智强 LI Jiong;JIANG Li;NING Guangfu;WU Jinbo;HE Zhiqiang(School of Automation,Central South University,Changsha 410083,China;State Grid Hunan Electric Power Company Limited Research institute,Changsha 410208,China;State Grid Hunan Electric Power Company Limited,Changsha 410014,China)

机构地区：[1]中南大学自动化学院,湖南长沙410083 [2]国网湖南省电力有限公司电力科学研究院,湖南长沙410208 [3]国网湖南省电力有限公司,湖南长沙410014

出　　处：《湖南电力》2023年第5期11-15,共5页Hunan Electric Power

基　　金：国家自然科学基金项目(52307231);国家电网有限公司科技项目(5216A321N206)。

摘　　要：提出了一种光伏板对地绝缘阻抗检测电路及检测方法,包含1个光伏板负极对大地的电压采样电路、2个电子开关和3个平衡电阻。为平衡光伏板负极与大地之间的采样电阻,在光伏板正极与大地之间并联一个与采样支路阻值相当的平衡电阻,在绝缘性能正常时,使光伏板负极与大地之间采样点电压不会出现极小的情况,降低对电压采样精度的要求。在光伏板正负极与大地之间分别并联一个由电子开关和电阻相串联组成的支路,各支路所串联的电阻阻值与满足漏电流标准的临界绝缘阻抗值相当。当光伏板某一极阻抗下降时,将另一极电子开关闭合,接入相应的平衡电阻,提高采样电压对电路阻抗变化的敏感度,从而计算出电路的实际阻抗值。此方法能够在低精度电压采样下得到准确的绝缘阻抗计算值,提高了检测的可靠性。This paper proposes a detection circuit and method of insulation impedance for photovoltaic array,which contains a voltage sampling circuit of photovoltaic negative electrode to the earth,two electronic switches and three balance resistors.In order to balance the sampling resistance,a balance resistor equivalent to the resistance of the voltage sampling branch is always connected in parallel between the positive electrode of the photovoltaic panel and the earth,so that the voltage of the sampling point between the negative electrode of the photovoltaic panel and the earth will not be extremely small when the insulation performance is normal,which reduces the requirements for voltage sampling accuracy.The branch consisting of an electronic switch and a resistor in series is connected between the positive/negative electrodes of the photovoltaic panel and the earth,and the resistor in series is equivalent to the critical insulation impedance that meets the leakage current standard.When the impedance of one electrode of the photovoltaic panel decreases,the other pole electronic switch is closed connected in parallel with the other electrode,and the corresponding balance resistor is connected to improve the sensitivity of the sampling voltage to the impedance change of the circuit,so as to calculate the actual impedance of the circuit.The proposed method can obtain accurate insulation impedance with low-precision voltage sampling,which improves the reliability of detection.

关 键 词：绝缘阻抗 平衡电阻 漏电流 光伏阵列 

分 类 号：TM854[电气工程—高电压与绝缘技术]