The Study Of Network Reconfiguration And Island Partition For Distribution Network With Distributed Generators Considered

In recent years, the penetration rate of distributed generators within the distribution network increases continuously which has influence on the operation mode of the distribution network in various aspects; And new demand on control measures of the distribution network has been proposed. The study of the techniques of the network reconfiguration and the island partition have contributed to absorb and utilize distributed generators fully by networks; Enhance the economy of system operation and the reliability of power supply; Improve power quality. The study is of great significance for the development and construction of strong smart grid. The thesis is mainly about:1) The basic theories of the network reconfiguration and the island partition have been introduced; The methods of mathematical modeling of the network reconfiguration and the island partition and their solving algorithm have been elaborated.2) According to structure characteristics of the distribution network, the concept of "virtual demand" has been introduced; And a directed graph based distribution network structure model has been proposed in which the direction of branch are alterable; And the feature of distribution network that it operates in dendroid mode can be guaranteed.3) The distribution network reconfiguration with distributed generators considered has been researched. By using the directed graph based distribution network structure model, an optimization model for distribution network has been proposed, which is targeting at reducing network losses; The proposed optimization model has been converted as a mixed-integer quadratic programming problem for easy solution.4) The island partition strategy and model with distributed generators considered has been studied. First, Two new concepts, "virtual node" and "virtual branch", have been introduced to modify the directed graph based structure model, adjusting to the feature of the islanding operation mode of the distribution network; Then, a islanding model of distribution network with distributed generators considered has been proposed with tie switches operability, the load priority and controllability and operation characteristics of distributed generators considered; The proposed islanding model has been converted as a mixed-integer linear programming problem; Furthermore, various islanding strategies have been discussed and analyzed under different scenarios.These proposed optimization models have been built on AMPL platform; A modified IEEE 33-bus system and a modified PG&E 69-bus system have been served for demonstrating the effectiveness and the reliability of these proposed optimization models.