Capacitor provides reactive impedance that causes proportional voltage to the line current when it is series connected to the line. The compensation voltage is changed regarding to the transmission angle δ and line current. The delivered power P S is a function of the series compensation degree s where it is given by
The reactive power compensation and voltage control is primarily performed by selecting shunt devices that are shown in the first line of the figure. The SVCs are capable to present more accurate and smoother control comparing to mechanically switched shunt compensators.
This paper reviews different technology used in reactive power compensation such as synchronous condenser, static VAR compensator, capacitor bank, series compensator and shunt reactor, comparison between them, source of reactive power and different optimization techniques.
In the first stage, reactive power compensation at each load in the systems is implemented for increasing the power factor into 0.9. In the second stage, metaheuristic methods are employed to determine the location and size of additional capacitors at nodes in distribution lines.
In this paper, reactive power compensation in radial distribution systems has been investigated in reducing total power loss. On the contrary to other previous studies, the study has used local compensation at each load for increasing power factor to 0.9 and then capacitors in distribution lines have been placed as other studies.
In the first step, given power factor of each load node is predetermined and then capacitor at the load node is calculated based on the known power factor, active power, and reactive power of the load. In the second step, the total compensation power of all capacitors at electric loads is determined.