Placement of shunt VAR systems

Static VAR Systems (SVSs) are becoming increasingly important in the damping of power system oscillations and a number of papers discussing the control of SVS for this purpose have been published. In this paper, however, the position of the SVS is discussed and it is shown that in simple cases the SVS should be placed slightly closer to the generator than to the load, and that for long lines several SVSs will give the best control. Further analysis is included to estimate the optimum placement of the SVS for a variety of loads and operating conditions. Computer calculations and model transmission line measurements are presented to support this analysis. The former includes an investigation into the effectiveness of the SVS as a function of its position for several cases. The conclusions are that, although no easily recognisable rule of placement emerges, poor choice of position can drastically reduce the influence of the SVS on transient stability and the calculations presented show that a compromise solution may be reached for any line whose operating conditions can be predicted.