Impact Of Distrubuted Generation On Distribution Network

As the problems of energy and environmental become increasingly sharp, the disadvantage of centralized power generation using conventional energy as driving force also becomes more and more obvious. At the same time, distributed generation, as an effective supplement of traditional generation, is getting more and more attention. Distributed generation is a flexible, efficient and environmental friendly way of power generation. It is an importment direction in the energy development field. With the connection of large number of distributed generators to power grid, the traditional distribution network is changing from a single source, radial structure to a multi source, gridding structure. As a result, changes should be made for the protection deveices and reliability evaluation to adapt the impact brought by the distributed power source. This article analses the influence of distributed generator on distribution network, with the foucs placed on relay protection and reliability assessment. The main work of this article is as follows:(1) This article introduces the definition of distributed generation, and carries on classification according to technical type, the energy they use, and the way they interconnected to the grid. Then discusses the working principle and respective advantages and disadvantages of several kinds of most widely used distributional power technology, including pv generation, wind generation, combined cold heat and power supply and micro turbines.(2) The working pricipal of relay protection device of traditional distribution network is introduced briefly. The influence of distributed generation on relay protection device running upstream and downstream of its access point is analysed, as well as the influence of distributed generation on this line and adjacent line when fault locates on the adjacent line. This article also analyses the impact of distributed generation on reclosing device.(3) Describes the main charcateristics and computing functionality of Powerfactory brifely, introduces its two short-circuit evaluation methods and their application, and analyses their calculation principles simplely. The focus is placed on Powerfactory's reliability calculation functions. This article introduces the application and main processes of reliability evaluation, and emphatically analyses the reliability assessment basing on states enumeration and failure effect analysis.(4) This article introduces the significance of reliability analysis, the common used reliability index, as well as common reliability analysis methods. Analyses the way distributed generation impacts on reliability assessment, research the model DG uses in reliability analysis, and finally in use of the Powerfactory's reliability calculation function analyses the impact of DG on the example system.