Reactive reserve management

A methodology is proposed in steady state to determine the output or setting of existing VAr/voltage control devices so that the allocation of reactive reserves guarantees that the system does not move towards voltage collapse as demand changes and that it will cope under credible contingency conditions. The procedure is to define 'reactive areas' by identifying 'weak' circuits and then to assess the distance to voltage collapse by the Q-distances illustrated. For security, an outage screening algorithm is employed and VAr rescheduling performed to limit any violations in a robust manner. The proposed global strategy has been prototyped on a computer by integrating algorithmic software and symbolic programming. Although the methodology is basically algorithmic, the use of knowledge-based systems technologies made the prototyping a simple task. The methodology is particularly useful for the operational planning phase of large power systems.