A direct calculation of power margin for transmission lines and buses in electrical power system networks

In this paper a technique is described for direct calculations of both real and reactive power limits that transmission lines can carry without losing system stability. The method is based on the technique of calculating the maximum power carrying capability for each transmission line. For each line of the system, the difference between the maximum power carrying capability and instant power is termed as the power margin. The proposed method uses data from local measurements and it is quite simple to calculate as it does not involve complex calculations. The remarkable characteristics of this technique is that it can be used for online monitoring without the requirement of load-flow solutions. Data collected from remote substations using SCADA or any other technique would make it feasible for online application. The proposed method has been tested on IEEE 118 Bus Reliability Test System and satisfactory results were observed.