Study On Static Voltage Stability And Reactive Power Control Strategy Of Large-Scale Photovoltaic Power Plants

Depletion of fossil energy and environmental pollution has brought new opportunities for development of Photovoltaic power which is a representative of the new energy. But with the increasing scale of photovoltaic power plants, voltage problem of photovoltaic power plants is even more serious. To solve the voltage problem in large-scale photovoltaic power plants, this paper focuses on the mechanism of voltage beyond limits and static voltage stability analysis of the large photovoltaic power plants. And a coordinated control strategy of photovoltaic power generation units is proposed to solve voltage problem and guarantee the stable operation of large-scale photovoltaic power plants.In this paper, considering the output power of photovoltaic array, and the internal resistance of the photovoltaic power plants, the steady-state model of large scale photovoltaic power plants is established. In view of the problem of voltage limitation for large-scale photovoltaic power plants, this paper analyzes the voltage of point of common coupling and voltage distribution in the large scale photovoltaic power plants, find out the mechanism of voltage beyond limits, and use simulation to verify it.In this paper, the static voltage stability was analyzed by calculating the minimum eigenvalues of Jacobin matrix of large-scale photovoltaic power plants. And the static voltage stability criterion and margin is obtained. And based on this analysis, the influence of the operation parameters on the static voltage stability of large-scale photovoltaic power station is studied by changing the light irradiance, the power grid impedance and the operating power factor. This paper calculates the sensitivity coefficient of ??min/?Qi to study the influence on system voltage stability within the photovoltaic power unit, and to provide guidance for the reactive power control strategy of large photovoltaic power plant.In order to solve the voltage limit and instability problems of large-scale photovoltaic power plants, a coordinated control strategy of photovoltaic power generation units is proposed to guarantee voltage within the specified range and improve voltage stability. By using the sensitivity coefficient of the characteristic value and the distribution of the voltage of each photovoltaic generation unit, the reactive power is distributed coordinately in each reactive power source. And this paper design a reactive power control system of large-scale photovoltaic power plants to solve the static voltage problem of large-scale photovoltaic power plants, and guarantee the stable operation of large-scale photovoltaic power plants.