Suppression Of Commutation Failure In Multi-infeed HVDC System Based On Station Control Of Electrochemical Energy Storage

Commutation failure is a prominent problem in HVDC(High Voltage Direct Current)transmission system.With the increase of the DC drop point of the load center,the receiving power grid presents a multi-infeed AC/DC hybrid structure,and the transient characteristics of the system become more complicated.The risk of HVDC commutation failure caused by faults increases,which seriously threatens the safe and stable operation of the power system.Electrochemical energy storage technology has developed rapidly in recent years.Due to the advantages of fast response speed and strong dynamic power adjustment capabilities,its largescale application will be a effective control method to improve the commutation failure problem in multi-feed HVDC systems.Therefore,it is a very meaningful work to carry out in-depth on the key technologies of the application of electrochemical energy storage power stations in multi-infeed AC/DC hybrid power grids.Based on the above background,this paper will focus on the problem of commutation failure in the multi-infeed HVDC system,and explore the application of electrochemical energy storage power station in the suppression of commutation failure in the multi-infeed HVDC system,and the coordinated control strategy with the common reactive power compensation equipment.This paper will aslo verify the control effect of the proposed strategy through simulation.The main progress made in this paper is as follows:(1)This paper comprehensively explains the commutation failure problem in the multiinfeed HVDC system,analyzes the concept of commutation failure from the perspective of the influence of commutation failure on the system stability,and sorts out the commutation failure situations of the multi-infeed HVDC system,Clarified the problems that need to be focused on and solved in the multi-infeed HVDC system.(2)Based on the actual engineering background,the Henan multi-infeed HVDC system model with electrochemical energy storage was built.The multi-infeed HVDC system was built according to the actual structure of Henan power grid.the electrochemical energy storage model is the mainstream lithium battery electrochemical energy storage power station in engineering applications.,so that the research work done in this paper is more in line with actual engineering.(3)Aiming at the subsequent commutation failure problem in the multi-infeed HVDC system,this paper analyzes the mechanism of the transient reactive power of the electrochemical energy storage power station on the HVDC commutation process,proposes an improved transient reactive power control strategy for the energy storage power station,and verifies that the proposed strategy can optimize the control effect of the energy storage power station through multiple sets of simulation conditions.(4)Aiming at the simultaneous commutation failure problem in the multi-infeed HVDC system,based on the difference between the dynamic reactive power response characteristics of the electrochemical energy storage power station and the synchronous condenser,this paper analyzes their respective advantages and disadvantages in simultaneous commutation failure suppression,and further proposes a coordinated reactive power control strategy between the energy storage station and the synchronous condenser.Finally,the simulation of typical operating conditions verifies that the proposed coordinated control strategy can form complementary advantages and achieve the overall optimal coordinated control effect.