Framework,Software Simulation And Practical Verification For Secure And Efficient Distribution Network Operation Based On Security Region

As a power system which supplies electric power for customers directly,distribution system plays a very important role in ensuring continuous power supply for customers.And safety,reliability and economy is the main focus of the planning and operation of distribution system.Smart grid will change the distribution system thoroughly,fast load transfer between transformers will be a new condition,on which,when transformer N-1 contingency occurs,load can be transferred not only between transformers,but also by switches of networks,which provides fundamental theory for Distribution System Security Region(DSSR).This paper discusses a new distribution operational mode under smart grid;and proposes a secure and efficient operational framework for future distribution network.Firstly,the effects on Total Supply Capability(TSC)and Distribution System Security Region of smart distribution network are analyzed.The theory of DSSR establishes the basis of a new operation mode,making the real-time security calculation possible.Operators can supervise the system and take action to regulate the state of systems by the visual technology of security margin,which ensures load can be safely transferred in case of an N-1 contingency.The theory of TSC is able to combine the substation supply capability and network transfer capability;therefore,the efficiency of distribution network can be significantly improved without adding the capacity of facilities under the N-1 security principle.Secondly,this paper proposes a security and efficiency-based mode and framework,which consist of functions,such as monitoring,alarming,control,optimization,risk evaluation and so on.Then,the new distribution operational mode is compared to the traditional distribution mode.Finally,an actual case with certain scale is presented to prove the framework and method proposed.Third,the program to realize DSSR method of calculation is accessd to the planning platform for urban power network,named CNP 4.0.Also,a large scale case is entered,and data of security boundary and security distance of operating points are calculated.The realization of the program in CNP 4.0 lays a basis to apply DSSR theory in future dispatching mode.Finally,an actual case is presented to analyse the secure and efficient distribution network operation method proposed.It turns out that the calculation of DSSR method and analysis results of summer great load meet the actual situation of the dispatch department.Thus,the theory of this paper is available and reliable.