Transmission Expansion in the Deregulated Power System Considering Social Welfare and Reliability Criteria

In the present paper, the authors propose a new method to determine an optimal transmission expansion plan in the deregulated power system. In the proposed scheme, social welfare and reliability are taken into account. Social welfare is computed from the summation of welfare of all market participants. On the other hand, reliability is determined from the cost of the loss of load or outage cost of consumers. Uncertainties such as generation, load, participant bidding strategies and facility availability are included in the planning problem. Uncertainties of generation and load are handled by using the analytical method while uncertainty of bidding strategy and facility availability are handled by using Monte Carlo simulation. In the proposed method, two transmission expansion cases: enhancing the existing transmission line capacity and investing in the new transmission line are investigated. In both cases, a set of transmission expansion plan candidates are picked up based on the social welfare sensitivity and price difference between buses. The most appropriate plan is selected based on three decision making approaches: average value, risk-based and probabilistic criterion. Numerical simulation is carried out for the modified IEEJ West 10-machine system