Study On System Architecture And Protection Configuration Scheme Of The Distribution Network Protection Intelligence Center

Urban distribution network is an important foundation to support urban development and the distribution network protection system is an important guarantee for the safety of urban distribution network.In the field of the distribution network, renewable energy is being accessed in the form of distributed power, and the micro-grid technology and DC distribution network technology are put into practical use. Therefore, the distribution system is being highly flexible and highly intelligent. But at this stage, distribution network protection is still using the traditional protection model by local information. It is not only unable to adapt to the value tuning and optimization problems brought by new energy accessing, bu also can not solve the problem being exposed in the distribution network. On the other hand, highly intense urban land makes the new substation construction particularly difficult, and the cost will highly increased. There is an urgent need to achieve a breakthrough in the architecture of the protection in the distribution network.To this end, this thesis proposes the concept of "The Distribution network Protection Intelligence Center ". The center in the distribution network can take over the function of several substations' protection. By the use of highly reliable communication network, each substation's data can be centralized. On one hand, it can provide better panoramic information for the integrated protection to achieve the function of remote backup for the local protection and area protection. On the other hand, it can also alleviate the pressure of substation's area in the city by concentrating the substation's secondary equipment.The Distribution network Protection Intelligence Center is divided into two layers, the local layer and the center layer. The local layer adopts the structure of distributed centralized configuration. The secondary equipment within the station can be integrated as local synthetic intelligence device. It can share and centralize station's information, providing fast and reliable protection for distribution network. The center layer adopts the structure of area centralized configuration. By the use of high-speed communication network between layers, it can collect area grid's information and realize the function of area protection and control. Through the thought of the Distribution network Protection Intelligence Center, this thesis explains the way to apply the Distribution network Protection Intelligence Center to the actual high voltage distribution network, providing the support for its promotion and application in the distribution network.For the character of collecting multisource data in the Distribution network Protection Intelligence Center, this thesis simplies the area grid to the topology only formed by dots and lines, proposes a quickly partition searching method by that topology, and constitutes the basic protection area of each element by using multi-terminal current differential protection principle. It is able to merge basic protection area to the generating protection area, configuring differential protection for the region when the data of the current cannot be acquired. This thesis studies the partition searching step and area differential protection under various types of complex structures in the distribution network, which shows that the strategy can achieve the function of area protection. And by using the software of PSCAD/EMTDC for all kinds of situation, the result shows that the partition searching and area protection strategy proposed in this paper is adaptable and effective.For the protection function under the Distribution network Protection Intelligence Center, this thesis proposes a design of remote backup triple protection and remote backup double protection. By using Markov model for the unique protection cooperation scheme, the state space diagram is built to calculate the rate of protection system's availability, refusing and malfunction. The result shows that, comparing to the local double protection method and the local single protection, the protection cooperation scheme proposed in this paper is pretty reliable and reasonable.In the end, the full text content is summarized and the development of the Distribution network Protection Intelligence Center is discussed.