Document Type : Review Paper


1 Electrical Engineering Department, Collage of Engineering, University of Mosul, Mosul, Iraq.

2 Electrical Engineering Department, Collage of Engineering, University of Mosul, Mosul, Iraq


Voltage stability of power systems reflects challenges to the power system operators due to its effect on the power systems components performances. Therefore, many solutions were invented in order to keep the systems within the voltage stability accepted limits. Because of the huge expansion of the power grids and the different loads natures on the grids, many techniques and solutions are used. The On Load Tap Changing Transformer (OLTC) was one of those techniques. In this paper, a review of past works that deal with the voltage stability limits, voltage stability improvement ways, OLTC types, the OLTC reverse action, and OLTC effect on voltage stability, in addition to several ways that make the OLTC work better. are discussed. The paper also sheds the light on the possible ways that may be employed to prevent the OLTC reverse action.  


Main Subjects

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