Optimal Control of Distributed Generation for Improved Security Constraint Management

The management of static security constraints (bus voltages and branch thermal limits) is one of the continuous tasks performed by operators. These constraints at any operating point can be divided into noncritical and critical constraints. To be secure, the system must fulfil both types of security constraints at all the time. While primary active and reactive power controls can manage noncritical constraints, emergency controls or remedial actions must be computed using optimal power flow (OPF) analysis to alleviate critical constraint violations. If the post contingency network involves a violation of critical constraints (which are not known a priori), conventional OPF algorithms may fail to converge and compute required control action, as the corresponding optimization problem becomes mathematically infeasible. Hence, the identification of critical constraint violations is necessary, as their location in the network decides the installation (during planning) and activation (during operation) of emergency controls. In this context, this paper first identifies the location of critical constraint violations using a metaheuristic approach, and then proposes a method to optimally place or control distributed generation to alleviate network thermal and voltage congestions during emergency situations.