一种优化的光伏电站直流系统绝缘在线监测装置设计

摘要

ABSTRACT:The insulation fault of the photovoltaic power station DC-bus to ground causes serious influence on the equi-pment operation and personnel security. The online monitoring of the DC system insulation is an effective way to prevent accidents from occurring and spreading. This paper compares the commonly used several kinds of insulation online monitoring principle,and uses the unbalanced bridge and balanced bridge combined method for the principle design and optimizes the traditional monitoring method from the view of engineering application,effectively prevent the short-circuit of the positive and negative DC bus which is caused when the switch fails. The paper also introduces the measuring principle,hardware design and software realization process in detail. Test results show that the accuracy of measurement devices and high voltage perfor-mance meet the design requirements.%光伏电站直流母线对地绝缘故障将会对设备运行和人员安全造成严重影响，对直流系统绝缘性能进行在线监测，是防止事故发生和蔓延的有效途径。比较了常用的几种绝缘在线监测原理，选择了不平衡电桥和平衡电桥相结合的方法进行原理设计，并从工程应用的角度对传统的监测方法进行了优化改进。有效防止了投切开关故障击穿时引起正负直流母线短路的问题。对所设计的光伏电站直流母线对地绝缘监测装置的测量原理，以及硬件电路设计、软件实现流程等进行了详细说明，并通过试验验证了装置的测量精度和绝缘耐压性能。