| Static ATC determines the maximum size of a transfer that can be implemented across a system without violating line thermal, bus high and low voltage, and static collapse constraints. The exact determination of ATC requires computationally expensive nonlinear simulations. ATC traditionally uses fast linear methods, which only predicting distances to thermal limits. This dissertation develops a theoretically sound and computationally efficient ATC screening algorithm to determining whether the transfer limiters will be thermal (in which case linear ATC is sufficient) or bus voltage and collapse (in which case the full nonlinear ATC is required). Based on limiter estimates, the method applies a decision rule that correctly classifies ATC cases as linear or nonlinear. The effectiveness of the developed algorithm is demonstrated in numerous examples, and offers a direct enhancement to the quality of ATC results and considerable reduction of its computational burden.; The prediction of the transfer size to reach the thermal limits is done using a fast method that incorporates the effect of reactive power flows in linear ATC. The estimation of bus voltage constraints is based on a system state approximation using an explicit polynomial expression on the transfer size. Generator reactive power limits are predicted using flow-based methods, and the collapse point is estimated using a complex flow-based necessary condition, which is demonstrated as part of this thesis. All the estimates are obtained from information exclusively from the initial operating point. Numerical examples on systems ranging from few to several thousand buses are used to describe and demonstrate the proposed tool. |
