Increase in High Impedance Value of Transformer to Reduce Short Circuit Fault Currents in High Voltage Networks

Abstract

Short-circuit current fault can have a bad impact on electric power systems that have high voltage levels. This adverse impact resulted in the burning of high-voltage equipment such as transformers. Several types of short circuit current faults that often occur in high voltage power systems such as line to ground, line to line, 2 lines to ground, and 3 phases. Circuit breakers can be a solution to disconnect the electric power system from short-circuit fault currents. In reality, there is still frequent damage to the transformer. The novelty of this research is to increase the high impedance of the transformer to reduce short-circuit fault currents in electric power systems that have high voltage levels. Several scenarios are made in order to be able to compare each change in transformer impedance to changes in short-circuit fault current. The first scenario increases the transformer impedance to 15% of its initial impedance. The second scenario increases the transformer impedance to 25%. Likewise for the third scenario the impedance increases to 35%. In the fourth scenario the impedance increase to 45%. Each scenario of increasing the value of the transformer impedance gives different results. Each scenario will be analyzed using a short circuit current measurement method at steady state. In addition, the fault current is also analyzed using the transient curve for the AC component, the DC component. The result is the lowest short-circuit fault current value occurs in the transformer with a high impedance percentage value of 45%. The higher the impedance value of the transformer, the lower the short-circuit fault current that occurs.