The Optimal Power Flow Algorithm Considering Load Power Factor Limits

Efficient reactive power operation enhances economic operation of the power system. To provide reliable and economic system operation, the acceptable load power factor must be analyzed according to the demand level of load bus. This paper presents two-bus equivalent method combined with stability index analysis to calculate acceptable load power factor range. The above method begins with searching the critical load bus with the line stability index, where the two-bus equivalent circuit is applied to determine the acceptable load power factor limit for the critical load bus. The acceptable range of load power factors is portrayed as bandwidths of load power factor expressed as a function of load level. After critical bus selection and load power factor calculation, an optimal power flow considering load power factor is carried out to optimize reactive power source. A case study using an IEEE 26 buses system is presented to demonstrate the suggested OFF method, and results show that system loss is reduced as well as load power factors are improved.