Voltage Unbalance on Alternators, its Effects & Solution, at Power Plants in Pakistan

Abstract

n Pakistan where grid is partiallystable and losses are in abundance, it is also observed that the heavy loads are not intelligently distributed thus causing load unbalance among all the three phases more over generating harmonics and negative sequence currents. In our work, we observe the behavior of a power plant unbalance voltage and current conditions which eventually affects the alternator windings, in some cases causes burning up of insulations. Our work indicates the percentage difference between balance and unbalanced system. More over analyzing the adverse effects of voltage unbalance on alternator’s stator & rotor and devising the solutions to minimize the effects through Analysis based analysis. Our work contributes to the solutions that electrical system can be balanced through several techniques e.g. changing the system configuration through manual and automatic switching operations to transfer load among networks. Reconfiguration can be performed to reduce loss and to balance loading across network. Un-allocating certain type of load especially inductive from the network can also reduce negative sequence currents. More over increasing the core size of alternator cables and crimping joints can increase the capability of alternator winding to with stand the immense voltage unbalance to a certain extent