UNINTERRUPTED LOAD TRANSFER BETWEEN TWO DISTRIBUTION FEEDERS WITH DIFFERENT POWER SOURCES

Abstract
This article shows the analysis for load transfer without interruption between two 23 kV distribution feeders. This procedure is not common in this type of system and requires paying primary attention to the characteristics of the electrical network for its application. The distribution circuits discussed here have their own power substation with different voltage levels. The information obtained from a state estimator, the contingency conditions, the electrical parameters of impedances and network configuration allow to carry out the simulation of the load transfer with the Alternative Transients Program software. From the simulation it is shown that load transfer without interruption is possible as long as certain operating conditions are met in the power and distribution networks. The dependence of the transfer on the voltage levels, angular phase shift of voltages and strength of the electrical network is shown, represented by its thevenin impedance at the interconnection point. The results found from the simulation indicate that the success of the interconnection is mainly a function of the electrical strength of the power substations and the phase sequence of the power transformer at the load transfer point. Certain percentages of variation of voltage and currents of the feeders are defined that must not be exceeded. The operational aspects proposed here serve as a basis to have a general interconnection procedure between distribution feeders where special attention is required in the continuity of the service due to the high expectation in the satisfaction of the user of the electrical network. Keywords: feeder, state estimator, medium voltage, power system, load transferring.