Reserve capacity assessment in small isolated electric power generating systems

The conventional approach to reserve capacity assessment in small isolated electric power generating systems is to use a deterministic procedure which recognises the possible loss of the largest generating unit and also some variation in the forecast load. These approaches do not normally include any explicit recognition of system risk and do not provide comparable risks for systems of different size or composition. The concept of system risk is presented in this article and illustrated by comparison with two basic deterministic procedures. A probabilistic framework for describing the wellbeing of the generating capacity in a small isolated system is proposed and illustrated. The wellbeing of the system is quantified in terms of system health and margin states, which incorporate the agreed deterministic criteria, in addition to a system risk index which describes the system inadequacy.