The Study Of Power System,s Anti Terrorist Attacks And Island Partition Of The Distribution System

As a social infrastructure, the power system crash under terrorist attacks, the social influence and the losses is enormous. So, how to avoid the attack and how to minimize the system loss when attacked is an increasingly popular topic.At the other hand, the distributed generation is becoming more and more common and the permeability of DGs is becoming higher and higher.How to formate the islanding operation by other independent power supply and improve the power supply reliability of power system when the system failure, is also a hot research. This paper conduct a study from the above two aspects and achieved a certain scientific research achievements. Based on all the above analysis, the following work has been done in this paper.Firstly, a new model and its solving method o0 f anti terrorist attack are presented in this paper. the bi-level optimization model is perfected by adding to the reactive power and voltage,and then the corresponding solving methods is put forward.First of all, through replacing the inner optimization of the bi-level model by KKT(Karush-Kuhn- Tucker) conditions, the bi-level model is transformed into a single level model. Furthermore, the single level optimization problem are decoupled into active power and reactive power optimization problem, then active power problem is simplified into a pure combination problem which can be approximately solved by using the maximum flow minimum cut, Finally the solution of the original bi-level model is transformed into the alternation optimization between active optimization and reactive power adjustment until meeting certain convergence condition. The results of several examples prove the validity of the model and algorithm in this paper.Secondly, considering island partition of distribution system for uncertainty of distributed generation and load, a new optimal island partition model and its solving method are presented based on tree knapsack problems(TKP) in this paper. The basic idea of the paper is as following: Firstly, a new stochastic island partition model considering the uncertainty of distributed generations and loads is constructed. Then the algorithm combining the Latin hypercube sample method with deterministic tree knapsack algorithm theory is used to determine the total island collection after sampling. And then this paper adopted two kinds of methods for statistical sampling results.Firstly, mathematical statistics method are adopted to determine the composition of the initial island. Secondly, the clustering method is used to determine determine the islands belonging of each node.Lastly, for each initial island, the stochastic optimal power flow is used to optimize and adjust the initial island on the basis of island reconfiguration. Through above optimization and adjustment, the security, optimization and economy for each DG island operation are ensured. The results of the example prove the validity of the model and algorithm in this paper.