Study On Impact Of The Grid-connected Distributed Generation On Voltage

With the continuous deterioration of the environment and the gradual lack of energy,distributed generation has begun to enter the distribution network because of its advantages such as small environmental pollution,high safety,and low cost.However,with the continuous increase in the number of grid-connected distributed generations,the stability of the grid voltage will be greatly impacted.Therefore,it is of great practical significance to study the influence of the distributed generation on the voltage of grid.In this paper,we first study the grid connection method,access requirements of wind power generation and photovoltaic power generation,and the mechanism of the influence of voltage on grid connection.It is concluded that the short circuit capacity,the variation of the power of the DG injection system and the power factor angle of the DG are three important factors that affect the system voltage impact of a single distributed generation.At the same time,the main reasons for the wide variety of DG's power change that are currently applied are analyzed.In order to evaluate the influence of DG on the steady-state voltage of distribution nodes,this paper proposes a stochastic power flow algorithm based on Monte Carlo simulation.The simulation results show that the proposed algorithm is feasible and reasonable.An in-depth study of the influence of DG on the distribution network voltage in three different situations with different access positions,different access capacities,and different power factors.It also compares the supporting effects of wind power and photovoltaic power generation on voltage,and proves that photovoltaic power generation is stronger than wind power generation.Finally,this paper builds a complete wind power and photovoltaic grid-connected model and related control strategies based on MATLAB/simulink,adjusts the output power of the distributed power source by changing the wind speed and irradiation intensity,and aims at the DG's output fluctuation instantaneously and the whole process to the power distribution.The influence of the voltage of important nodes in the network is simulated,and the trend of the feeder node voltage changes with the distributed generation's output power is obtained;The circuit breaker controls the input and output of DG and simulates the impact of the voltage of the grid-connected point.The results show that the input and output of the DG will cause acertain impact on the voltage of the power grid.The size of the impact and the capacity of DG is positive relevance.And it provides data support for the previous theoretical analysis.