Bus-bar splitting for enhancing voltage stability under contingencies

Abstract

As one of the network topology optimization ways, bus-bar splitting has been applied for various purposes. In this paper, the performance of bus-bar splitting on a look-ahead (i.e., short-term, say 30 min) power system (i.e., pre-splitting base case) with contingencies is evaluated. The proposed problem aims to find an ‘optimal’ bus-bar splitting scheme that can maximize the load margin of a look-ahead base case and ensure the load margin of each contingency case with a desirable level. Due to the complexity and nonlinear nature of the proposed problem, it is very difficult to be solved with the available solvers, and a large number of contingencies (including N−1 and N−k contingencies) and bus-bar splitting schemes need to be examined. A four-stage methodology is presented for online computing efficiency. Moreover, the group properties of contingencies are explored and illustrated in this paper, which is utilized to reduce the number of nonlinear constraints from a large number of contingencies and relieve the computational burden. The other advantage of the proposed methodology is that it can derive multiple effective solutions from which the operators can choose one. The effectiveness of the proposed methodology is demonstrated on the IEEE 118-bus and 1648-bus power systems with promising results.