Optimal Placement in Power Systems

This chapter deals with the optimal placement of power quality meters and flexible alternating current transmission systems (FACTS) devices in power systems. The chapter presents two recent applications of optimization techniques to power system planning. The first example addresses optimal monitoring programs of power system for voltage sags assessment. Voltage sags are short duration reductions of the rms voltage caused by the occurrence of remote short circuit faults. A meter placement method for voltage sags monitoring of a large transmission systems is presented. An integer programming based modeling is proposed for choosing the locations of a limited number of power quality meters. A branch and bound type algorithm is used to solve the optimization problem. A large transmission network is used to validate the proposed method and stochastic assessment of voltage sags is applied to the network to obtain simulated monitoring results. Voltage sag system indices are calculated from monitoring programs designed according to the optimization method. Comparisons with the system indices obtained from a full monitoring program show the applicability of the method. The second example considers the optimal placement of flexible alternating current transmission systems (FACTS) devices to reduce the transmission congestion problem in the deregulated power systems. The example deals with the congestion problem in the deregulated electricity market using an optimal power flow framework (OPF). The congestion management method considered is based on a constrained re-dispatch of generation schedule which are formed by the market. From the re-dispatch, the congestion management cost can be evaluated. The installation and operation of the flexible alternating current transmission systems (FACTS) devices in the transmission network is considered in order to alleviate congestion and minimize the amount of active power which has to be re-dispatched. A cost-benefit analysis to evaluate the economical justification of using FACTS for congestion management is also proposed. The IEEE 14-bus system is used to simulate the market and illustrate the proposed method. The study results show that when FACTS devices are included in the network, the amount of re-dispatched power is greatly reduced resulting in an optimal operating point closer to that dictated by the market settlement and that FACTS is a viable option for congestion management, from a technical as well as economical point of view