Research On Distributed Bus Protection In Smart Substation

With the rapid development of technology of smart substation, Protection relay have developed from conventional protection to more extensive application of digital protection, Conventional protection use CT to gain analog information, Digital protection directly obtain and use an electronic transformer (ECT) to send digital information. Distributed bus protection has the advantage with scattered arrangement, which will be widely used in the reason of conforming the overall design of the smart substations and IEC61850thought. Although the substation structure has changed, the bus protection are also using a replica of the traditional substation busbar differential protection’s principle, it is necessary to get a new setting and improved bus differential protection.First,smart substation related technology and the influence to bus protection were introduced, including concepts of the smart substation, structure, intelligent equipment, etc, and after new technical application separately influence to bus protection’s structure, the installation and the principle is analyzed.Based on this thesis of the characteristics of smart substation, a detailed study of distributed bus protection schemes is done, a solution in the smart substations proposed fully distributed bus protection is discussed. Proposed bus phasor differential protection and the sampled differential protection in the smart substation, a new restraint criteria free from the bus current outflow internal fault are disscussed. Then, constructed a simulation system in PSCAD, demonstrated the great positive effect in reliability, sensitivity to bus differential protection.Distributed bus protection exchange information through the network, make protection in close connection with communication, conform the basic characteristics of the smart substations. Modeling distributed bus protection based on the IEC61850standard is the key applications in the smart substations.Finally, the research contents are summarized, and future research directions are also prospected.