Study On Fault Line Selection Technology For Digital Substation

With the development and application of network technology, fiber communication technology, computer technology and optoelectronic device manufacturing technology, it is a trend that a technology based on IEC 61850 standard in the digital substation will alternative to traditional substation automation technology rapidly. In distribution networks, single-phase ground fault is the highest probability of fault type. In order to improve power supply reliability, it is important to selec the fault line timely and accurately. As an important function in the substation automation system, fault line selection in the digital substation should have the appropriate solutions.In this paper, the background, the purpose and the advantage in substation automation system of IEC 61850 protocol standard is analyzed. And it is analyzed that the technical features of the protocol standards.The fault line selection technology for the distribution network and the characteristicness of the digital substation is studie. Base on IEC 61850 standards protocol, the function of the fault line selection is descrbed as logical node. With the description abou data of logical node, it is established the fault line selection of the Intelligent Electronic Device(IED) model including the logical node model and the logical device model.Aiming at the difficulty of single line to ground fault detection in neutral compensated power networks. This paper presents a fusion scheme for line to ground fault detection in compensated power networks based on evidence theory and information entropy. Fault characteristics as initial abrupt wave, real power and transient are employed in the proposed fusion method. Using three fault characteristics, algorithm of fault measures is constructed that representing the likelihood of a line tend to be the fault one. And the problem of fault line selection will translate into D-S evidence theory model. Evidence theory is formulated for fusion strategy in this paper. Simulations and field fault data prove the reliability and adaptability for line to ground fault detection.Finally, the scheme of the fault line selection IED is discussed in the digital substation. Sample value massage of the fault line selection IED is captured base on FPGA system. The results of fault line selection is translated to background management system base on Manufacturing Message Specification(MMS)...