VaR-based operating reserve assessment in composite power systems

BASSOTTI, G.; OLSINA, F.; GARCÉS, F.

Belen, Brazil

Conferencia; XI SEPOPE; 2009

Operating reserve levels is traditionally set by system operators as the largest generating unit, a percentage of the system peak load or a mix of both. This criterion while it’s easy to implement doesn’t consider the stochastic nature of the system components. This paper proposes an alternative that uses a probabilistic approach, based on a risk assessment. The approach presented here is based on the calculation of the value at risk of a power system. The value at risk index (VaR) has been typically used by financial and insurance companies but its application on electric power system has been limited to long term planning stages. On this paper, this risk assessment method is introduced for setting the operating reserve requirements considering the electrical network constraints. This novel approach to compute the reserve requirement through the use of the theory of value-at-risk considering a composite power system is divided in five sections. First, a short introduction to the problem is made. Then, the theory of VaR of a power system and the proposed approach is explained as to be applied in a composite power system. This approach is tested in IEEE reliability test system where the full composite generation and transmission system is considered. Finally, the conclusions about the use of VaR index in the power systems reserve assessment are discussed.