Short-Circuit Current Limitation

In this paper, two methods of limiting three-phase short-circuit currents are considered: the first is by splitting the low-voltage winding of a power transformer, and the second is by connecting a current-limiting line reactor to a two-winding power transformer on the high-voltage side. Experimental studies have been carried out, which allowed to quantitatively assess the amplitude values of the resulting short-circuit currents and their reduction when applying the above methods. Based on the experimental data, simulation models have been created in MATLAB Simulink software package: the first one allowing to quantitatively evaluate the reduction of short-circuit currents depending on the power of the power transformer when splitting the low-voltage winding, the second one: the reduction of short-circuit currents when using a current-limiting linear reactor of the selected rating. The created simulation models allow to select the required parameters of short-circuit current reduction to ensure the necessary sensitivity of relay protection devices. Graphical dependences of arising values of short-circuit currents for power transformers of different capacity with voltage 10/0.4 kV, as well as the magnitude of their reduction when applying the considered methods are constructed.