The output power of photovoltaic power generation devices varies with natural factors such as sunlight, weather, season, temperature, etc. The output power is unstable, especially when the output power changes significantly, which can cause voltage fluctuations and flicker at the system access point. The photovoltaic power generation system converts solar energy into direct current energy through photovoltaic modules, and then converts it into alternating current energy through inverters. During the conversion process, a large number of harmonics are generated.

So real-time monitoring of harmonics is necessary during grid connection. If it exceeds national standards, corresponding measures such as installing filtering devices need to be taken. The power factor of photovoltaic power generation is relatively high, usually around 0.98, which is basically active output. To meet the principles of reactive power compensation layering, zoning, and balance, photovoltaic power stations should be equipped with corresponding reactive power compensation devices to meet the demand of the power grid for reactive power.

Photovoltaic power generation is connected to the grid through power electronic inverters, which can easily cause three-phase current imbalance. When a fault occurs on the photovoltaic power generation system line, it can easily affect the relay protection and reclosing action of the power grid. Due to the significant impact of photovoltaic power grid connection on the power quality of the public power grid, the state stipulates that photovoltaic power stations must be used at the grid connection pointPower quality monitoringdeviceConduct long-term monitoring of power quality.

Characteristics of power quality monitoring devices:The voltage input adopts a high voltage isolation module, and the current input adopts a high-precision current transformer, which isolates the input signal from the measurement system and greatly improves the anti-interference ability of HD DZ300B.Adopting a Chinese interface and simple button operation, it is convenient for users to use,Meet the requirements of national standard A-level instruments.

Reference algorithms are used for harmonics, three-phase imbalance, flicker, and fluctuations, without approximate calculations. High precision A/D (16 bit) is used for simultaneous sampling, with a collection rate of 12.8 kHz.Adopting the DSP+ARM+CPLD kernel, it has fast processing speed and rich software functions, making HD DZ300B suitable for complex testing and data processing work, greatly improving testing efficiency and level.