Research On Virtual Energy Storage Control Method Based On Power Spring

Energy saving,emission reduction and green power industry have jointly promoted the rapid development of renewable energy power generation.As the main form of renewable energy power generation,due to the impact of intermittent nature of renewable energy,the output power of DG is random and hard to be predicted.Therefore,the intergration of large scale DGs will cause the fluctuation of distribution network bus voltage,and also the fluctuation of demand side power in distribution network.To solve the problem of DG intergration,and increasing the allowable capacity of DG in distribution network,both traditional energy storage technology and VS control technology have been widely concerned by scholars all over the world.However,traditional energy storage has high price and limited capacity,VS technology which is based on 0-1 load control is not flexible and cannot regulate reactive power.Therefore,in order to solve the above problems,and increasing the allowable capacity of distribution network for large-scale grid-connected DG,a concept of VSbES and its control methods are proposed in this paper based on the ES theory.The main contents of this paper are as follows:1.The control method of single VSbES is studied.The power control models of single VSbES are established,which include the active power control model and the reactive power control model.Based on the models,the control method of VSbES is analysed,and its control loops are also designed,which include the amplitude control loop and the phase control loop of ES output voltage.Besides,a simulation is conducted to verify the method above.2.The adaptive improvement of single VSbES control method is studied.The operating surface diagram of VSbES is achieved,then based on which,the principle of regulating volume oscillation while NCL switches in,and the principle of regulating volume deviation while NCL switches off are analysed repectively.Based on the current feedback,the improved adaptive control method of single VSbES is proposed,and simulations are also conducted to verify it.3.The cooperative control strategy of multiple VSbES is studied.The principle of multi-agent technology is analysed,and by integrating the treelike multi-agent architecture and the annular multi-agent architecture,the multi-VSbES hierarchical collaborative control architecture based on multi-agent is established.Based on the improved particle swarm optimization algorithm,the upper-level control strategy of multi-VSbES cooperation is studied,and both the object function and constraint conditions are setted.At the same time,the lower-level control strategy of multi-VSbES cooperation is proposed,and simulations are conducted to verify the above methods.4.Taking a regional power grid in Jiangning,Nanjing as an applieation environment,the applications of VSbES in power system are studied.Let VSbES only participates in active power regulation,apply it to suppress the demand side power fluctuation of distribution network with DG,and the load real-time price response,study the principle and carry out the case analysis respectively.Let VSbES participates in active power regulation and reactive power regulation simultaneously,apply it into the anti-islanding protection for DG integration,study the principle and carry out the case analysis respectively.By the above examples,it can be proved that VSbES can realize many functions in power system,and the allowable DG capacity of distribution network can be enhanced effectively.