Impact Of Wind Farms Distributed Access Distribution Network On Relay Protection And Solutions

At present,China wind power development is rapid,access to distribution network in the form of distributed power of the wind power capacity is more and more big,the number is increasing,therefore,the distribution network original topology structure and the load flow distribution will be had a great influence,especially when short circuit fault occurs,wind farms access to change the magnitude,direction,and duration of the short circuit current,which affect the judgment of the relay protection device,and even cause relay protection device misoperation,and threat to power grid safety.It can be seen that the research on the influence of wind farms distributed access distribution network on relay protection and the solution is of great significance to the sustainable development of wind power in China.Firstly,analyzed the structure characteristics of traditional distribution network in China,analyzed the action principle,protect tasks and requirements of traditional distribution network relay protection device in detail,and describes the composition of distribution network three-step current protection.Secondly,analyzed theoretically different wind power capacity and different point of failure in both cases,impact of wind farms access to distribution network on short circuit current and relay protection,and according to the theoretical basis,through ETAP simulation software construct model,simulation proves the above theory influence.The results show that the different capacity wind farms and the different location of fault points in the distribution network can cause different effects on short circuit current and relay protection.The larger capacity of wind farms,the greater short circuit current provided,the more likely to cause protection misoperation;When the fault points are respectively in upstream,downstream and between of wind farms,increase,reverse and out flowing short circuit current provided by wind farms easy to cause protection misoperation.Finally,according to the simulation results of wind farms access to distribution network on relay protection influence,propose the longitudinal protection solution,and through theoretical analysis and simulation verification.The results show that introduction of longitudinal protection in distribution network with wind farms,when short circuit fault occurs,the longitudinal protection is not affected by wind power capacity and location of fault points,the fault can be removed accurately in all cases.Final confirmation,longitudinal protection scheme can effectively solve the influence of wind farms access to distribution network on relay protection.