This paper proposes the compensating strategy of static var generator(SVG)for multi-node voltage imbalance in power grid. Firstly

the multi-node unbalance mathematical model of power grid is established by combining symmetrical component method

and the mechanism of single SVG compensating multi-node voltage imbalance is analyzed. Secondly

the optimization problem of SVG is formulated with two different network unbalance control targets(minimize the sum of squared negative sequence voltage amplitude at each node and ensure the voltage unbalance factor not to exceed 2%)

and solved by nonlinear programming theory and geometric assistant analysis. On the basis of these

this paper proposes that a comprehensive management system can be built by the combination of power quality monitoring equipment and SVG

and the online control of this SVG can be realized by online impedance measurement and online instruction optimization. Finally a simple grid model is built in PSCAD to verify the effectiveness of the proposed method. This work is supported by National High Technology Research and Development Program of China(863 Program)(No. 2015AA050606).