New Method for Voltage Stability Analysis of Radial Distribution Networks

Abstract

In this Thesis work, an attempt has been made for voltage stability analysis of electric power distribution system. A new formula for computing the voltage stability index (VSI) of all nodes of any distribution network is proposed in this thesis work. The node having the minimum value of voltage stability index is the most sensitive node. Using three different examples, 29−node, 33−node and 69−node radial distribution network, it has been shown that the node having the minimum value of voltage magnitude becomes the most sensitive node using the proposed method which is also the end node. The critical values of total real power load (TPL) and total reactive power load (TQL) for constant power, constant current, constant impedance, composite as well as exponential load modelling is derived out for the sub-station voltage of 1.0 pu, 1.025 pu and 1.050 pu respectively for 69−node radial distribution network. The system will actually collapse beyond the computed values of TPL and TQL because load-flow based methods have a tendency to collapse before the exact critical values of TPL and TQL. The superiority of the proposed method has been established by comparing with other methods available in literature.