As we all know, the inherent characteristics of photovoltaic power station and the change of grid structure after access to the grid will have an impact on the power quality, planning, operation and relay protection of the grid. In the scheme of photovoltaic block generation, centralized inverter and local boost grid connection, the power quality monitoring before grid connection is particularly important. Whether the power quality of grid connected inverter meets the national standard directly affects the safety and stability of the whole grid.

The precision of our smr-em series power quality on-line monitoring device meets the national standard and has passed the authoritative certification of Xuchang Kaipu laboratory. It has the characteristics of high precision, large capacity, small size, high cost performance, safe and reliable performance. Online power quality monitoring system can monitor and count voltage, current, power, power, frequency, unbalance, harmonic, flicker, fluctuation and other power parameters.

The power quality measurement of photovoltaic power station is more stable and effective by installing power quality online monitoring device. The location selection of online power quality monitoring device should be the location of each node of distributed grid connection, which can give full play to the performance of the device and facilitate the monitoring and control of each line.

In order to analyze the action of photovoltaic power station accidents and automatic safety devices in the process of accidents, so that the power grid dispatching organization can fully, accurately and real-time understand the action of relay protection devices in the process of system accidents, fault recording devices should be installed in photovoltaic power station. Fault recorder can record the situation from 10 seconds before fault to 60 seconds after fault. The fault recorder shall include the necessary number of channels. The fault dynamic process of photovoltaic power station records the change process of relevant system electrical parameters and the action behavior of relay protection and safety automatic device after the occurrence of system large disturbance such as short circuit fault, system oscillation, frequency collapse, voltage collapse, etc. The AC voltage and current signals of the parallel point of photovoltaic power station need to be connected to the fault recording device of photovoltaic power station. The protection action signal and power quality on-line monitoring output signal can be connected to the external trigger node of fault recording.