Research On PVGS And D-STATCOM Voltage Support Planning And Configuration Under Random Grid Faults

With the domestic photovoltaic generation system(PVGS)grid-connected capacity continued growth,the interaction between PVGS and the power grid has become increasingly prominent.The photovoltaic grid-connected inverter uses a fully controlled power electronic interface,and has a consistent circuit topology with power quality control devices such as distributed static synchronous compensator(D-STATCOM)of the distribution network,which makes PVGS reduce the voltage sag.Governance becomes possible.Today,power users have stricter requirements for power quality.Voltage sag is one of the main causes of power quality problems,and most voltage sags are caused by various short circuit faults in the power grid.Aiming at the distribution network voltage sag caused by grid fault,which leads to sensitive load losses,a method of supporting local distribution network voltage by bi-level optimal configuration of PVGS and D-STATCOM is proposed.First,fully considering the photovoltaic output randomness,the output condition of minimum grid voltage support is derived.Based on this,the position and capacity of PVGS is configured,ensuring better voltage support for other conditions.Then,the fault probability model based on Monte Carlo method and sensitive load loss function considering voltage sag are established.Second,improved discrete particle swarm algorithm by using a new probability mapping function and inertial weights(CIBPSO):The limitations of traditional continuous and discrete particle swarm optimization algorithms are elaborated.A new probability mapping function is used to improve the global and local search capabilities.The shrinkage factor guarantees the search efficiency of the algorithm.The benchmark function is simulated to verify the advantages of the algorithm.a bi-level planning model is established,taking minimum sensitive load losses in the distribution network as upper layer for PVGS configuration,and best economic goal as lower layer for D-STATCOM configuration.Their capacity and position are solved by discrete particle swarm optimization algorithm.Finally,the IEEE 33-node system is simulated.The results show that comparedwith the traditional D-STATCOM local configuration,the proposed method effectively improves the PVGS utilization,saves the D-STATCOM investment costs,supports the distribution network voltage and reduces the sensitive load losses.