Study On Fault Isolation Of Distribution Network With Wind Turbines

With the rapid development of society, the requirement of electricity is growing.Meanwhile, people raise higher demands about the power supply in the distributionnetwork. As one of the main tasks of distribution automation, fault isolation has the abilityto detective the problem area accurately and isolates the fault quickly.In recent years, the technology of wind power generation has refined. More and morewind turbines will be operating in the distribution network. When a fault occurs, the size,direction and distribution of the fault currents are changed. Then the equipments in thedistribution automation system could not action correctly. In order to solve this problem, itis necessary to propose an effective strategy about fault isolation of distribution networkwith wind turbines.This paper firstly introduces the action processes of three main types of wind turbineduring the fault. It includes the LVRT technology and transient current. On this basis, itanalyzes the impact to fault isolation of distribution network from wind turbines.Secondly, according to the fault energy balance theory, the distributed fault isolationalgorithm for distribution network with wind turbines is proposed. After that, it presents themain points and process about the realization of this scheme.Thirdly, it gives the presentations about inter-harmonics generating mechanism of theVFDs and the fluctuating loads. By analyzing, the effect to Fourier algorithm frominter-harmonics is obtained. Then a new over current detection algorithm is proposed.Finally, by theoretical analysis, the LVRT characteristics of wind turbines are obtained.After that, the related simulations for the FSIG have been done in MATLAB software.Then according to the LVRT characteristics of wind turbines, two fault isolation strategiesare proposed which could enable some wind turbines to keep on running after the fault.