Central China Branch of State Grid Corporation, Wuhan 430077, China
To solve the problem that off-line section and limit can"t well match the system running state, a set of algorithms are proposed for searching and limit setting of transmission section components. Flow transferring amounts of three types of faults, i.e., branch breaking, active component tripping and bus tripping are calculated by DC method, and a method of transforming bus tripping into breaking several virtual short lines is proposed to make the power flow transferring relationship explicit. General linear expressions for three power flow transferring types are concluded, which lays a foundation for setting section limits. The thermal stability section searching method based on "risk branch line+threatening component" constitutional law is demonstrated. By using the general expressions of power flow transferring, a risk-weighted monitoring index construction method and a limit setting method for sections are proposed. The merging method is given for the similar sections consisting of parallel branches, and the simplification method of monitoring index is given for the sections composed of parallel branches. To ensure the solving speed and accuracy, the calculation strategy by combining DC searching method with AC correction method is adopted. Based on an actual example, the searched sections by the proposed algorithm cover all the thermal stability risks of the off-line sections, furthermore, the consistency of section limits between the proposed algorithm and the off-line calculation is proved, and thus the validity of the proposed algorithm is testified. A round of calculation consumes about 3.6 minutes, which meets the requirements of on-line application.
LIU Yang,YAN Faqi,WANG Yang,et al.Online Algorithm For Searching and Limit Setting of Thermal-stability Weak Section[J/OL].Automation of Electric Power Systems,http://doi.org/10.7500/AEPS20190921006.