Effect of mutual coupling to the reactive power placement of power systems

A systematic procedure for determining the optimal location and discrete sizes of compensation shunt capacitors for distribution systems by considering the mutual coupling among phase conductors and grounding effect has been developed. The equivalent circuit models of distribution line segments are derived so that the mutual coupling will be included in the computer simulation. The MINOS package is applied to solve the highly nonlinear objective function subjected to voltage constraint and discrete capacitor size. A sample distribution feeder is used for computer simulation to verify the proposed methodology. It is found that the optimal capacitor placement solved by using the conventional positive sequence circuit model will introduce higher cost due to overcompensation of shunt capacitors for distribution systems. It is concluded that reactive power planning will yield a better solution