Loss based performance index for the reactive power control

The reactive power is the major drawback of the AC electric grids. This paper proposes a performance index, "Q/loss", based on the energy loss share of the MVAR flows. If computed with powers, the performance index is time-dependent and characterizes one grid operating regime. Calculated on energy basis, it stamps the quality of the MVAR control over a period of time. As outlined by simulations conducted for various IEEE test-systems as well as on a region of the Romanian transmission grid, the performance index ranges from few percent to some 15%. The energy loss related to the MVAR flows can be either be allocated to the grid operator or carried over the corresponding ancillary service: reactive power supply for voltage regulation.