Adnan Ahmed, Noor Ullah, Muhammad Idrees



Design and Simulation of Improved On Load Tap Changer (OLTC) to Mitigate Voltage Sag/Swell

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Many electrical and electronics equipments miss operate or stop working during voltage sag and swell. Due to this the entire industrial process disturbs, which leads not only to great financial loss but also caused of many accidents. Therefore it is necessary to avoid the tripping of these equipments during voltage instability or voltage sag /swell. There are some typical FACT devices which are used for voltage regulation i.e. DVR, STATCOM, UPFC and back to back converter. However these devices are not only costly but the synchronization of the voltage is also a challenging task. In this research work the conventional OLTC is replaced with a new one OLTC having the ability of fast transfer switching to mitigate voltage variation very fast. The fast transfer switching is made possible via bi-directional power triacs. The OLTC is connected to three phase variable power supply, the variable power supply is varied from 150 to 250 Vrms and the output voltage is measured by voltmeter and found in the range of 210 - 230Vrms which is a nominal voltage of a 220 Vrms system. The OLTC tap switching time is analyzed by oscilloscope and the results are shown below.


Power Quality, Voltage Sag/Swell, DVR, OLTC, Fast transfer switch


Cite this paper

Adnan Ahmed, Noor Ullah, Muhammad Idrees. (2020) Design and Simulation of Improved On Load Tap Changer (OLTC) to Mitigate Voltage Sag/Swell. International Journal of Power Systems, 5, 95-105


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