| At present, China power grid has entered the development of high-voltage, large generator units and a large power grid, putting forward higher requirements for power system planning. The transmission network planning is an important part of power system planning and is a necessary condition for power system stable development. However, there is a lack of arithmetic and software which can be integrated assessment reliability and economic impact. In the practical evaluation work, economic indicators are still mainly used to assess planning project. The evaluation results are closely related to experts involved in the network planning and its understanding. Different experts may make different views on the same problem, leading grid companies with limited funds be difficult to grasp the priority of each project.On the basis of the preview research, this paper proposes a new quantitative assessment reliability index QRI and planning project investment value index PPIV. The former can be used for quantitative assessment of contribution to the reliability of the grid after a single planning project construction and the latter transforms the reliability index to the cash inflow of economic index by fitting the unit cost of the loss of power shortage, in order to calculate PPIV.Therefore, PPIV is a improved NPV indicator which considered the reliability benefits of planning project.In order to verify the effectiveness of the algorithm, this paper develops the planning project investment valuation procedure based on MATLAB platform, and put forward innovative solutions in the three modules of reliability calculation to improve actual operation speed in the the power grid. The first is presenting an algorithm of the relevant line set to narrow grid contingency collection to solve the problem which is using the entire network fault set to calculate the reliability index. The k shortest path search algorithm is used to find the line sets what produce the power flow visible change before and after of a planning project construction. The second is for the current trend of generating power flow calculation documents for transmission planning assessment completely rely on manual changes, this paper presents a algorithm based on the common subgraph in order to improve the automation level of transmission planning assessment. The third is developing a data interface for BPA and TRELSS based on the MATLAB software platform, in order to read the operation mode data directly from scheduling departments.Finally, this paper uses the 2012 planning projects of Guangdong power grid for the study cases. And the valuation of investment and prioritization of 500 kV planning project is completed to verify the validity and usefulness of the indicators and algorithm proposed by this author. The research results provides an effective analysis tool for the decision-making of planning management department, which laid the foundation for the engineering application. |
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