Bidding Surveillance Indices and Their Application

Market monitoring has been identified as a basic function in the deregulated electricity environment. In order to supervise power suppliers´ bidding behaviors and abuse of market power, three surveillance indices are put forward in this paper, including capacity price index (CPI), bidding difference degree (BDD) and out-of-merit capacity index (OCI). CPI is defined as price-weighted sum of normalized value of all blocks capacity; BDD is defined as the area between two normalized bidding curves; and OCI is the ratio of the out-of-merit capacity of a unit shares of its actual bidding capacity to the value system surplus capacity accounts for system available capacity at a trading period. The actual historical bidding data of a certain provincial electricity market in China is then analyzed in detail to test the proposed indices. The results show that the three surveillance indices can sensitively detect the abnormal bids and abnormal changes in suppliers´ bidding behavior exist in electricity market in time. Therefore, the three surveillance indices are applicable to be effective part of market monitoring systems for a healthy market