Investigation of several OPF applications in the Vietnamese power system

The Vietnamese power system is in phase of development. Due to the increase in the size and complexity in this system with the strong exchange of power between the North and South regions via a long link, the optimization of planning and exploitation of this system becomes essential. In order to ensure the quality of supply of energy, safety and economy in several operating condition for this system, the optimal control strategies are necessary. Thus this paper presents several applications of optimal power flow with different objective functions for this power system such as economic dispatch, voltage/Var control and control strategies in order to avoid risk of voltage instability. An optimal method based on indicator of voltage instability is developed.

I. Introduction

The Vietnamese power system is in phase of development. Due to the increase in the size and complexity in this system with the strong exchange of power between the North and South regions via a long link, the optimization of planning and exploitation of the this system becomes essential. This system must be able to meet the continually changing load demand for active and reactive power. The system should supply energy at minimum cost. The quality of power supply must meet certain minimum standards with regard to the constancy of frequency and voltage and the level of reliability. Several levels of controls involving a complex array of devices are used to meet the above requirements. The control objectives are dependent on the operating state of the power system. Under normal conditions, the control objective is to operate as efficiently as possible with voltages and frequency close to nominal values. When an abnormal condition develops, new objectives must be met to restore the system to normal operation.