Load Transfer Between Distribution Feeders From Different Substations Without Power Interruption: A Case Study

The interruption of electricity supply to users of a distribution network is common if the load is transferred between feeders from different substations. Furthermore, every time this action is made, most of the times it may come together with long time interruptions of the service on some branch of the circuit or power interruption of a complete feeder. In Mexico, load transfer through synchronizing distribution feeders at a point outside the substation usually leads to service interruption to customers. This article shows the results of the interconnection of two Mexican distribution circuits of 23 kV, and they are fed from different substations. The supplier company provides historical measurements of voltage phasors on different points of the feeders. The obtained information from the simulated contingencies, state estimator, and parameters of the electric system is used to perform the simulation of load transfer on the Alternative Transients Program, and some calculations in steady-state-like contingency analysis, short-circuit calculation, and phasor analysis are made. The results indicate that a successful interconnection is highly related to the state of the transmission grid, the voltage phasors in power transformers, and the location of interconnection point. The aim of this article is to show the effect of the elements that allow a load transfer without interruption between two distribution feeders that have different power sources.