Research On Fault Location And Power Restoration Strategy Of Distribution Network With Distributed Generation

As an important part to ensure safe and stable operation of power system,quick and accurate respond to judge and find faults is critical for grid security and preventing large-scale blackouts.And quick and perfect power restoration strategy is critical to maximize the protection of non-fault area load supply and improve power supply reliability.Therefore,the study is to propose fault location algorithm and formulate power restoration strategy that can be applicable in distribution network including Distributed Generation.First of all,in view of the fact that mass penetration of Distributed Generation is unable to accurately reflect the location of fault or even failure location,a new method of fault location which common to various fault types based on improved impedance is proposed according to ? equivalent circuit model and the transition resistance of reactive power characteristics for zero.In order to quantify Distributed Generation impact on short current due to the failure of the system,the fault point current calculation,the fault current and voltage of each line segment in active distribution network are estableshed.And on this basis,the iterative calculation method of load power by taking advantage of the monitoring data of each power supply access point FTU device considering transmission loss is established,which can reduce the setious influence of load fluctuation on the accuracy of fault location algorithm.The validity of the proposed method is verified through the simulation under different operation conditions.Then,a fault location algorithm of small cerrent grounding active distribution network based on zero-sequence current mutation is proposed by analyzing single-phase grounding fault current characteristic of active distribution network which neutral point via arc suppression coil grounding and determining the booster interconnection transformer winding connection mode of distributed generation.The fault location algorithm is completed through fault start and location.The ground fault start algorithm based on the zero-mode voltage transient energy is proposed and fault location algorithm based on the zero-sequence current mutation characteristic is formulated.Finally,in order to solve the problem of dispatching management of Distributed Generation in power restoration,a communication method of island partiton based on the breadth-first search algorithm is proposed considering the type and operation characteristics of Distributed Generation,the operation of contact switch and the load priority ect.And in view of the problem that regrid of Distributed Generation in power restoration,FTU synchronization module is extended and a quick adjustment of grid connected measure based on the V/f control strategy are proposed.Via the distribution network model with Distributed Generation in PSCAD simulation software,FTU synchronization module and the quick adjustment of grid connected measure based on the V/f control strategy are simulated to verify the feasibility of the coordination between control strategies.