Fuzzy Approach to Nodal Reliability Ranking for Radial Distribution Networks

Power distribution systems are exposed to load swings and faults, which can lead to voltage instability and collapse. It's important for a distribution engineer is to identify the sensitive nodes so that corrective action can be taken. This paper presents a fuzzy logic methodology to rank the distribution system nodes based on its reliability. For calculating reliability of nodes, paper defines a new index 'Percentage Reliability', which is a function of Voltage and Voltage Stability Index. The proposed technique predicts nodes critical to voltage collapse and provides inputs information for corrective action. This ensures reliable distribution system. For the load flow calculation purpose, a three phase fuzzy load flow algorithm for unbalanced radial distribution systems is developed, which is based on algebraic recursive expression of the voltage magnitude.