Assessment of up and down spinning reserve considering transmission constraints

In this paper a new model is proposed to schedule the capacity of both up and down spinning reserve (SR) considering transmission constraints. Up SR is seen as the most important resource to cope with many contingencies and it is well studied, while the down SR is ignored by many papers especially when network constraints are considered. Ignoring the down SR would cause sub-optimal or even unfeasible solution. In this paper an iterative process is proposed to schedule up and down SR and the importance of down SR will be analyzed and illustrated. At each iteration of the process, the up SR cost is firstly minimized with respect to reserve constraints and reliability constraints and then the sum of expected interruption cost and down SR cost is minimized with respect to various post- contingency constraints under each contingency event to alleviate transmission congestion. The effectiveness of the proposed method is demonstrated by the Roy Billinton Test System (RBTS) and the results are analyzed to illustrate the significance of down SR in the market-clearing model with transmission constraints.