Voltage control capability of SVC with var dispatch and slope setting

Voltage control capability of SVCs is decided by their var reserves, regulation slopes and available margins. In this paper, a sensitivity model for var dispatch is proposed to restore the var reserve of SVC while keeping desirable voltage profile, and the control capability of SVCs is defined by the available control margin, the slopes, the reference voltage, the static voltage characteristic of the system. The susceptance increment for expected compensation is found to define the critical SVC possibly violating the control limit, and coordinate outputs of SVCs at different locations.The numerical results show: (1) the operation point of SVC is controlled by var dispatch of the synchronous machines with satisfying accuracy; (2) the load’s response to voltage variation reduces the control effect of SVC; (3) lower slope setting or higher reference voltage yields more var output, and vice versa; (4) the control capability for SVCs at different locations may be coordinated to better utilize their var reserves.