Optimal reactive power dispatch by pseudo-gradient guided particle swarm optimization

This paper proposes a pseudo gradient based particle swarm optimization (PGPSO) method for solving optimal reactive power dispatch (ORPD) problem. The proposed PGPSO is the particle swarm optimization with constriction factor guided by pseudo-gradient for better search ability. The implementation of the pseudo-gradient in PSO is to determine the suitable direction for particles to guarantee that they can quickly move to global optimal solution. The proposed PGPSO has been implemented for the ORPD problem with different objectives such as minimizing the real power losses, improving the voltage profile, and enhancing the voltage stability satisfying various constraints of reactive power limits of generators, switchable capacitor banks, bus voltage limits, transformer tap changer limits, and transmission line limits. The proposed method has been tested on the IEEE 30-bus system and the obtained results are compared to those from other PSO variants and other methods in the literature. The result comparison has indicated that the proposed method can obtain total power loss, voltage deviation or voltage stability index less than the others for the considered cases. Therefore, the proposed PGPSO can be a favorable solution method for dealing the ORPD problem.