TEPCO-BCU for on-line dynamic security assessments of large-scale power systems

Abstract

The current direction of development for fast transient stability assessment is to combine a reliable direct method and a fast time-domain method into an integrated methodology to take advantage of the merit of both methods. TEPCO-BCU is developed under this direction by integrating BCU method, BCU classifiers, and BCU-guide time domain method. Current version of TEPCO-BCU is able to perform exact stability assessment and accurate energy margin computation of each contingency of large-scale power systems. Exact stability assessment is meant to classify stable contingencies as stable and unstable contingencies as unstable while accurate energy margin computation is meant to give accurate critical clearing time of each contingency of large-scale power systems. To bypass the difficulty of checking the one-parameter transversality condition of BCU method, the concept of the boundary property has been proposed and a group-based BCU method has been developed. This paper has described on-line transient stability assessment results of TEPCO-BCU program on a 12,000-bus power system data. Feasibility study of applying Parallel TEPCO-BCU to on-line transient stability evaluation in terms of speed and accuracy of stability assessment has been conducted. It has been found that the wall clock time needed to process 3,000 contingencies on the 12,000-bus system is 29.5 minutes, 15.5 minutes and 3.1 minutes respectively on a 1-node, 2-node and 10-node configurations. Given a credible list of contingencies, TEPCO-BCU system can fast screen out critical contingencies. This capability in conjunction with some relevant functions can lead to several practical applications. These relevant functions include the energy function method, the controlling UEP coordinates and their sensitivities with respect to parameters or control actions. (14 pages)