Intelligent And Economic Operation Of A Substation Based On Active Distribution Network: Theroy And Practice

Active Distribution Network (ADN) is proposed as a system-level solution in order to adapt to the development trend of distribution system. The main features of future distribution system are the increasing permeability of distributed generation, the wides use of intermittent load and the implementation of demand side management,. The core of ADN is to make each part of a distribution network actively take part in the collaborative optimization, thus ensure the safety and economic network operation. Substations are core hubs of a distribution system, so their safety and economic operation is of great significance.In an ADN environment, the load fluctuation of a substation is far more frequent and significant, which greatly increases the difficulty of its safety and economic operation. This paper firstly systematically introduces traditional optimal substation transformer operation arrangement strategies. Then analyzes the problems arising when these strategies are applied in ADN environment, and introduced the author’s study around these problems. The paper proposes an intelligent economic operation strategy of substation transformers, which is formed by four parts:the equivalent simplification method of predictive load curves, the division of control periods, dynamic optimization of transformer operation combinations and the safety solution dealing with unexpected sharp increase of load. This strategy can minimize the substation operation loss under the premise of safety.Based on the strategy proposed above, the paper further considers two typical cases in ADN. Firstly, the switching frequency of substation devices is higher in an ADN than in a traditional distribution network. The loss of device life caused by frequent switching should not be neglected. Therefore this loss is to be considered within the optimization of a substation’s economic operation pattern.This paper takes the life loss as a switching loss, constructs a model for the switching loss of transformation of different operation patterns, and takes switching loss into consideration when performing the dynamic optimization of transformer operation patterns. Secondly, taking proper advantage of the Demand Side Management (DSM) applied in an ADN can effectively even the load curve, improve the substation capacity efficiency and the energy efficiency, enhance the robustness to cope with the unexpected load uprush in a near future period. Based the strategy above, the paper further proposed a load shifting strategy, from both perspectives of pattern optimizing and eliminating unexpected sharp load increase.Simulation result shows:applying this strategy, substations can not only run safety but also economically even when load varies frequently and significantly.