The method of traditional active compensation for the neutral point voltage is realized by injecting a theoretically calculated current into the neutral point of the distribution network(DN). The insulation resistance of the DN affecting the compensation effect on the neutral point voltage is usually ignored. Neither is it possible to control the neutral point voltage flexibly. When the parameters of DN change

the traditional method has to measure them frequently. So it isn't effective for DN whose system architecture and parameters change frequently. A new method based on the idea of the difference method is proposed. By injecting an initial current into the neutral point of DN

and controlling the amplitude and phase of this current simultaneously

flexible control of neutral point voltage is achieved ultimately. Not only is this method able to suppress the neutral point voltage at zero

but also it can suppress the neutral point voltage to an arbitrary non-zero target. It has such advantages as fast convergence

simultaneous adjustment to the amplitude and phase of the injection current

and wide application range that together make it usable in the DN whose system structure and parameters change frequently. Its feasibility has been verified by simulation. This work is supported by National Natural Science Foundation of China(No. 51107143).