Research On Power Supply Restoration Strategies Under Fragile Grids In Areas With Concentrated Small Hydropower

With the rapid development of China’s power industry,the scale of interconnected power grids across regions of the power system is becoming larger and larger,and the interaction between subsystems is also becoming larger and larger.Although with the continuous development of power technology,the automation level has been improved,and the reliability of operation has been improved accordingly,there is still a certain probability of the failure of power supply in the operating system.For example,if some systems in the operation failure of power supply,there may be further transformed into a large or large area due to the incorrect action of some automatic devices,and even more serious,the collapse of the whole power system will be caused by the interaction of various subsystems.As we all know,the use of electric energy has penetrated into all aspects of our lives,so once a large-scale failure of power supply occurs,it will inevitably affect our normal life from a small point of view,and from a large point of view it will inevitably bring huge losses to the national economy.Therefore,it is particularly important for the power supply departments in each region to formulate the power supply restoration strategy that is in line with their actual power grid.This paper is mainly based on the actual situation of a certain area of Yunnan power grid,after a large-scale power failure occurred in the power supply area,the quick restoration of power supply to this area was studied.The main contents of this paper are as follows:Firstly,it gives a brief overview of the current situation of the Power Grid.At the same time,it classifies the data surveyed from the Power Supply Bureau,classifies all kinds of data,screens and summarizes the data which are needed.It mainly includes the network structure of the power grid,the information of generators in the area under the jurisdiction of the Power Grid,the basic operation parameters of the Power Grid and the information of important users in the area under the jurisdiction.Then it establishes the main body of the study,establishes the multi-objective optimization problem with the total generating power and the recovery path distance as the objective function,uses Floyd shortest path algorithm to obtain the recovery path distance,and introduces the principle of how to search the path,and also explains the rules of updating the system after each unit is started.The NSGA-II algorithm is used to solve multi-objective problems,an entropy weight comprehensive evaluation method is proposed.And the best solution of the Pareto optimal solution is obtained by combining the entropy weight comprehensive evaluation method.Then,it is applied to the Power Grid,and the power supply restoration scheme of the Power Grid is obtained by MATLAB simulation.For the proposed power supply recovery scheme,small disturbance stability analysis is needed for the small systems generated after the increase of units and lines to determine whether the updated small systems can maintain stability,and then identify the feasibility of the proposal.Finally,in order to better adapt to the actual situation of the regional power grid and the development and construction of the future power grid,the idea of flexible power supply restoration research for the regional power grid is put forward.The main part is to judge and frame the areas of out power supply under different circumstances.After that,the research of power supply recovery is carried out for different power loss areas.