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Traditionally Security Constrained Optimal Power Flow and VAr planning methods consider static security observing voltage profile and flow constraints under normal and post contingency conditions. Ideally, these formulations should be extended to consider dynamic security. This paper reports on a B.C. Hydro/CEPEL joint effort establishing a Dynamic Security Constrained OPF/VAr planning tool which considers simultaneously static constraints as well as voltage stability constraints. This paper covers the details of formulation and implementation of the tool together with the test results on a large scale North American utility system and a reduced Brazilian system.

The objective of contingency screening and ranking function is to shortlist a specified number of critical contingencies from a large list of credible contingencies and rank them according to their severity. This paper summarizes the work conducted as part of the EPRIA3.C. Hydro on-line voltage stability project in developing a Contingency Screening and Ranking (CS&R) module. The two methods of Reactive Support Index (RSI) and Iterative Filtering are derived in this paper and tested on the large scale systems of B.C. Hydro and another Major Unnamed Utility. The results obtained indicate that RSI on its own or in combination with the Iterative Filtering method can be used for CS&R depending on the acceptable level of misranking. The RSI method is a very fast and powerful CS&R method and is suggested for systems where some misclassification of contingencies can be tolerated. On the other hand, for systems where an exact list of critical contingencies is intended, then the Iterative Filtering method can be used for screening complemented with another method like RSI for ranking. The latter technique is being integrated in the EPRU6.C. Hydro On-line Voltage Stability tool.

The location of SVC (Static VAR Compensators) and other types of shunt compensation devices for voltage support is an important practical question. This paper considers a tool based on the determination of critical modes. Critical modes are computed by studying the system modes in the vicinity of the Point of Collapse. System participation factors for the critical mode are used to determine the most suitable sites for system reinforcement. Because the method does not rely on base case linearizations, the method is able to properly consider all system limits and nonlinear effects. The paper tests the proposed method by performing an assessment of the impact of the addition of Static VAR compensators to a 1380 bus model of the BC Hydro system.

This paper summarizes BC Hydro's experience in applying neural networks to dynamic security contingency screening and ranking. The idea is to use the information on the prevailing operating condition and directly provide contingency screening and ranking using a trained neural network. To train the two neural networks for the large scale systems of BC Hydro and Hydro Quebec, in total 1691 detailed transient stability simulation were conducted, 1158 for BC Hydro system and 533 for the Hydro Quebec system. The simulation program was equipped with the energy margin calculation module (second kick) to measure the energy margin in each run. The first set of results showed poor performance for the neural networks in assessing the dynamic security. However a number of corrective measures improved the results significantly. These corrective measures included: 1) the effectiveness of output; 2) the number of outputs; 3) the type of features (static versus dynamic); 4) the number of features; 5) system partitioning; and 6) the ratio of training samples to features. The final results obtained using the large scale systems of BC Hydro and Hydro Quebec demonstrates a good potential for neural network in dynamic security assessment contingency screening and ranking.