Optimization Strategy Of Distribution Network Voltage Considering Distributed Photovoltaic Active Power Reduction

As the PV penetration rate in the distribution network continues to increase,the effect of distributed photovoltaic power(DPV)on the distribution network voltage is significantly increased.The randomness and uncertainty of the DPV output power and the mismatch with the power consumption of the load make the voltage fluctuation of the distribution network increase,and the problem of voltage overrun is more prominent.The DPV is generally connected to the grid through the inverter,and the PV inverter has the bidirectional reactive power adjustment capability,which enables the distributed power source to actively participate in the voltage regulation of the distribution network and adjust the active and reactive power of the output according to the voltage and power requirements.From the perspective of realizing the voltage qualified of the whole network and the minimum voltage deviation and maximizing the consumption of photovoltaics,this paper proposes a pre-optimization voltage strategy for the distribution network that takes into account the DPV active power reduction.Firstly,considering the uncertainty of DPV and load output power,the complex affine method is used to divide the time to establish the uncertainty model.On this basis,the pre-reactive optimization model is established with the sum of the node voltage deviations of each time period as the objective function,and the algorithm of complex affine nesting into particle swarm optimization is used to solve the problem.The optimization result is the optimal photovoltaic reactive output value,the tap changer of the on-load tap changer and the number of switching sets of the reactive compensation capacitor.Secondly,considering the limit of the number of actions of the on-load voltage regulating transformer and the reactive power compensation capacitor group in one day,the dynamic reactive power optimization model is established and the reactive power optimization result is used as the initial value in each period by the optimal segmentation-joint optimization method.The optimal segmentation number is the maximum number of allowed actions,and the optimal segmentation point is the device action time.Finally,the voltage optimization strategy of the distribution network with PV active power reduction is proposed for the period when the voltage is still over the limit after the reactive power optimization is completed.The value of the on-load voltage regulating transformer and the reactive compensation capacitor is set as the dynamic reactive power optimization result,that is,the optimal value.With the minimum total reduction of photovoltaic active power in the whole network as the objective function,under the constraints of the operation of the photovoltaic inverter,the PV reactive power value and the active power reduction value that are needed to make the voltage not exceed the limit are optimized,and no reactive power optimization is needed.In this paper,the IEEE33 node system is selected to verify the above optimization strategy.The simulation results show that the proposed optimization strategy of the distribution network voltage considering the DPV active power reduction can reasonably control the active power and reactive power of the photovoltaic power supply to participate in voltage regulation.Solve the voltage fluctuation and over-limit problem caused by the high-permeability photovoltaic power supply after grid connection,and reduce the voltage deviation of the whole network.