A new approach to reduce the expected energy not supplied in a power plant located in a non-expandable transmission system

The main objective of most of power plants is to inject power as much as possible into the grid from the power plants. However, the transmission system may restrain the output capability of the power plant, especially, if the power plant is located in an area of non-expandable transmission system. In this situation, any disturbance in the nearby transmission system may force the plant to generate lower than its rated value, which disables it from selling the remaining available generated power to the costumers and also increases the cost of energy not supplied. In this paper, an efficient method is proposed to determine the maximum output capacity of the power plant, by which the avoidable cost of energy not supplied, is not burdened on the plant. The effectiveness of the proposed method has been evaluated on a three machine test system and also on the actual large Mashhad power plant in Iran

A new approach to reduce the non-linear characteristics of a stressed power system by using the normal form technique in the control design of the excitation system

In this paper, a new approach is presented to reduce the nonlinear characteristics of a stressed power system by reducing its second-order modal interaction through retuning some parameters of the generator excitation system. In order to determine the second-order modal interaction of the system, a new index on nonlinearity is developed using normal form theory. Using the proposed index of nonlinearity, a sensitivity function is formed to indicate the most effective excitation system parameters in the nonlinear behavior of the system. These dominant parameters are tuned to reduce the second-order modal interaction of the system and to reduce the index on nonlinearity. The efficiency of the proposed method is validated using a four-machine two-area test system. Simulation results show that a proper tuning of the excitation controller can reduce the second-order modal interaction of the system and can even improve the transient stability margin of the network