TITLE:
Investigation and Mitigation of Transformer Inrush Current during Black Start of an Independent Power Producer Plant
AUTHORS:
Salman Kahrobaee, Marcelo C. Algrain, Sohrab Asgarpoor
KEYWORDS:
Black Start; Distributed Generation; Inrush Current Mitigation; Independent Power Producer; Transformer Energizing
JOURNAL NAME:
Energy and Power Engineering,
Vol.5 No.1,
January
4,
2013
ABSTRACT:
The
energizing of large power transformers has long been considered a critical
event in the operation of an electric power system. When a transformer is
energized by the utility, a typical inrush current could be as high as ten
times its rated current. This could cause many problems from mechanical stress
on transformer windings to harmonics injection, and system protection
malfunction. There have been numerous researches focusing on calculation and
mitigation of the transformer inrush current. With the development of smart grid,
distributed generation from independent power producers (IPPs) is growing
rapidly. This paper investigates the inrush current due to black start of an
IPP system with several parallel transformers, through a simulation model in
DIgSILENT Power Factory software. The study demonstrates that a single genset
is capable of energizing a group of transformers since the overall inrush
current is slightly above the inrush of the transformer directly connected to
the generator. In addition, a simple method is proposed to mitigate the inrush
current of the transformers using an auxiliary transformer.