Researching On Optimal Allocation Of Distributed Power In Medium Voltage Distribution Network

Worldwide conventional energy crisis, environmental crisis and the electricity crisis have become increasingly prominent. The big drawbacks of centralized power generation system are particularly prominent. Distributed power is an effective complement to large grid systems, large grid system with distribution power combining is the direction of the electric power enterprise reform, but also reduce energy consumption, investment, system security and it is an effective way to improve flexibility. However, a large number of distributed power accessing to has had a profound impact on medium voltage distribution network, which must be fully coordinated with the contradiction between large distributed power system, mining distributed power advantage in economic, energy and the environment. Especially at the start from the root, optimize distributed power access locations and injection capacity at the planning stage; fault information in a clear operational phase, the development of rational strategies divided island, and in a targeted manner to restore power according to the load characteristics, thereby improve system reliability, and ultimately to reach the role of medium voltage distribution network optimization.So far, the main contents are as follows:(1) First, there will be a brief introduction of the definition of distributed power, classification and influence on medium voltage distribution grid. Summarize the impact of distribution power access location, injection capacity on distribution grid voltage and network losses, through test operation mode;(2) It describes the relevant knowledge of graph theory, the distribution network topology analysis and flowing calculation method. Distribution network will be equivalent to a connected graph composed of nodes and branch, combined with graph matrix representation and tree traversal mode to search and store data, formation of the search forward and backward substitution method based on hierarchical theory; then according to special handling for distributed power special processing methods in power flow calculation to improve and validate flow calculation method;(3) It will establish an integrated and coordinated system security and economy optimization model, and use a novel search algorithm of Gaussian cuckoo search to optimize the access problem of distributed power. Ensure security and stability in the distribution network on the basis of considerations to minimize the environmental costs of electricity distribution networks to optimize the overall investment cost target, so Gaussian cuckoo search algorithm was first introduced for distributed power access locations and injection capacity in parallel optimization. Benchmark function test algorithm with performance and the algorithm, the original cuckoo search algorithm and particle swarm algorithm are applied to solve IEEE 33 node with distributed power system access issues, and validate algorithms for superiority over;(4) It will also address known distributed power access information and fault information, and consider the extent of the load rating and controlled using the "search + parity" to develop ideas for solving islanding strategy and runs through the island to improve system reliability. Combining connectivity tree diagram theory of distributed power to the root node of the tree to establish connectivity model, will have the greatest benefit of the program to restore power to the initial division of the island’s model, the application of search forward and backward substitution method check whether the voltage and power limit, and adjust the power distribution within the island, in order to determine the best optimization.