Calculation of total transfer capability incorporating the effect of reactive power

Abstract

Total transfer capability (TTC) is an important index in power markets with large volume of interarea power exchanges and/or wheeling transactions. In this paper, a mathematical programming approach is proposed to calculate the TTC considering reactive power and voltage effects. The objective function is to maximize the power transmission between specific generator(s) and load(s) subject to the constraints of load flow equations and system operation limits. Since the reactive power generation is taken as a control variable in the formulation, the bus voltages can be optimized to yield maximum transfer capability. The model tends not to hamper the sales capability of the existing generators in the market, but rather finds out additional allowable transactions for that particular system operating condition. The adopted approach can avoid the conservativeness of continuation power flow (CPF) methods. The sequential quadratic programming (SQP) is used to solve the problem. The computer results from a 4-bus test system and the IEEE 30-bus system show a great potential of the proposed method in calculating TTC.