光伏发电直流侧共模电压干扰的抑制研究

光伏电站直流监测系统的放电管持续闪烁放电会导致通信异常和印制板烧毁,阐述了其排查、分析和处理方法。通过对现场测试波形曲线、干扰源耦合通道、印制板通信防雷回路等方面进行分析,得出其主因是由逆变器开关管工作过程中对地产生的共模电压未得到有效抑制而引起的。经过现场设备电路接地回路改造并测试验证,问题得到有效解决。在光伏电站投运前应对各相关设备及电磁干扰进行专门严格的设计和检测,可有效地抑制共模电压,提高系统性能。

Research on suppression of photovoltaic DC side common-mode voltage interference

The abnormal communication and PCB burning will occur due to the continuous flashing of the discharge-tube in the DC monitoring system in the PV power generation station. Thus this paper elaborates how to find the problem, make an analysis and shoot the troubles. Through the analysis of the test waveform, the coupling channel of the interference source, the communication lightning protection circuit of the PCB and so on, it concludes that accident is mainly caused by the common-mode voltage in the inverter switch-tube has not been effectively restrained during runtime. After the transformation of the grounding circuit of the equipment, through test and verification, the problem is effectively solved. In order to suppress common mode voltage and improve system performance, it is necessary to design and test the relevant equipment and EMI strictly before the photovoltaic power station is put into operation. This work is supported by Science and Technology Project of State Grid Corporation of China (No. 5292C0140113).