An accurate equivalence method of distribution system for transmission system operational reliability assessment

In the modern power system, the uncertainty on the power supply and electrical load will aggravate the volatility in the transmission system. Therefore, the accurate operational reliability evaluation of the transmission system is very important to guarantee the stableness of the power grid. The existing method is to equate the distribution system as a constant load of transmission system according to the rated capacity, which cannot reflect the uncertain factors and power demand changes in the distribution system, which caused the inaccurate of the results in reliability evaluation. To solve the above problems, an accurate equivalence method of distribution system for transmission system operational reliability assessment is proposed in this paper. Firstly, the concepts of load demand classification level and failure load level are proposed to reflect the variation of load level and component reliability changes in the distribution system respectively. Secondly, based on the concept of discrete convolution operation, the load demand classification level and failure load level are combined to construct the model of the accurate load expectation of distribution system. Finally, the distribution system of BUS5 in the RBTS transmission system is used for test, and the effectiveness of the accurate equivalence method of distribution system is verified. (c) 2023 The Author(s). Published by Elsevier Ltd. This is an open access article under theCCBY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).