A new method for voltage stability evaluation of distribution network

This paper presents a new method for voltage stability evaluation of distribution network. Making use of the node voltage equation, a direct load flow solution method is found at first. This load flow algorithm can directly derive the voltage correction on imaginary axis of every node without any iteration. Then the derived correction on imaginary axis is inserted into the voltage equation which has been simplified, and a quadratic equation about the voltage correction on real axis is obtained. The root discriminant of this quadratic equation is used as a new voltage stability index for distribution network. The derived direct load flow algorithm and the method of voltage stability evaluation have been tested on IEEE 33-bus distribution system. Finally, the load flow results obtained from the direct algorithm is very similar with standard results worked out by New-Laphson method. And the proposed method for voltage stability evaluation of distribution network is the same with the conventional method, it also can accurately reflect the voltage stability of distribution system without load flow results.