An improved system operation for better voltage stability and reduced losses

This paper presents a new technique named Phasor Relativity based Mathematical Technique (PRM Technique) for coordinated automatic voltage control of the power system for enhanced voltage stability. The PRM control system is implemented on standard IEEE 14 bus system and an equivalent South Indian EHV system and results are presented for three different cases. The first case is the system with no control of reactive power. The second case is system with shunt reactors permanently connected while coordinated voltage control is present only at generators, tap changers and switched shunt capacitors. In the third case a new variable reactive power device called Controlled Shunt Reactor (CSR) is introduced in the place of fixed reactors and the same control strategy is implemented. All the cases are studied and compared to analyze the advantages of the CSR implementation in EHV systems. While CSR can provide variable reactive power support independently based on prevailing local voltages, the implementation of coordinated control provides additional system security and optimum operation. PRM control system with PMU technology can be proposed as a good smart grid technology.