Study On Substation-area Protection Of Fuzzy Cluster Based On Fault Degree And Gray Correlation Degree

A series of new technologies, such as intelligent primary equipment, networkedsecondary equipment and IEC61850communication standard, have been applied tosmart substation. Thus the real-time sharing of multi-source panoramic data and theinteroperability between devices in substation have been realized, then theinformation interaction barriers could be eliminated completely. All thetechnologies provide extremely favorable conditions to study substation-areaprotection (SAP) based on the real-time sharing of multi-source panoramic data.Therefore, the main research contents of the dissertation are protection principle andapplication of SAP for smart substation.Firstly, a new type of SAP based on fault degree is presented. The fault degreeand its expression are defined based on the consistency of fault component currentof each side of a single element, and the authenticity and comparative of faultdegree can be improved by the same method. The SAP based on fault degree and itsapplication are discussed in detail in this paper. The results demonstrate that theSAP can identify fault components quickly and accurately, and also can avoid thebad influence of CT ratio inconsistent and CT saturation.Secondly, a new type of SAP based on gray correlation degree is proposed. Fora single element, the protection algorithm based on gray correlation degree ispresented through the gray relational analysis of fault component current of eachside of a single element within data window. The algorithm determines faultcomponents through the relative size of gray correlation degree, and has a naturalanti-CT saturation capacity. On this basis, the SAP based on gray correlation degreeis proposed, which can identify fault components quickly and accurately, and has anatural anti-CT saturation capacity and high safety performance.Thirdly, four statistical indices characterizing the state of a single componentare defined based on fault degree and gray correlation analysis, that is, fault degree,non-fault degree, fault gray correlation degree and non-fault gray correlation degree.Then, the SAP of fuzzy cluster based on fault degree and gray correlation degreeand the substation-area lock protection (SALP) based on fuzzy cluster are presented.In addition, the scheme of SAP is designed, when faced with fault, the SALPestimates whether it is substation-area internal fault firstly, and if so, the SAP willdetermine and remove the fault component, otherwise lockout the SAP system directly, providing a new idea for the construction of SAP system.Meanwhile, in order to verify the methods proposed above, typical substation-area simulation models are constructed in PSCAD, based on which a large numberof fault simulations are carried out, and then large amounts of fault data areprocessed with Matlab. The results demonstrate the feasibility and the effectivenessof the method.