Smart
transformer (ST) is a power electronic based transformer equipped with
effective control and communication. It is expected to play a significant role
in future power distribution system, however, their operational features in the
medium voltage (MV) power distribution systems are yet not explored. In this
paper, operation and control of ST are presented for improving its performance
and operational range in a power distribution system consisting of two radial
feeders in a city center. For investigating the performance of ST in above
system, one conventional power transformer (CPT) is replaced by the ST whereas
other feeder is continued to be supplied through the CPT. In this scheme, the
ST is operated such that it makes total MV grid currents of the combined system
balanced sinusoidal with unity power factor. Therefore, in addition to
providing continuous and reliable operation of ST based loads, the ST can also
improve the performance of the loads which are supplied by the CPT in a
different feeder. Moreover, the proposed scheme eliminates the need of power
quality improvement devices at the other feeder. Therefore, the scheme also
makes the application of ST in the distribution system cost effective.
Simulation results validate the suitability of ST in improving the performance
of multiple feeder medium voltage power distribution system.
KEYWORDS:
1. Smart
transformer (ST)
2. Medium
voltage rectifier
3.
Power distribution system
SOFTWARE: MATLAB/SIMULINK
BLOCK DIAGRAM:
Fig.
1. A schematic of conventional power distribution system consisting of
two
radial feeders in a city center.
Fig.
2. Simulated waveforms when ST is not compensating for feeder II. (a) PCC
voltages. (b) Grid currents. (c) MV rectifier currents (d) Feeder II currents.
Fig.
3. Simulated waveforms when ST is compensating for feeder II. (a) PCC voltages.
(b) Grid currents. (c) MV rectifier currents (d) Feeder II currents.
Fig.
4. Simulated waveforms during transient conditions when load in feeder II is
changed. (a) PCC voltages. (b) Grid currents. (c) MV rectifier currents (d)
Feeder II currents.
CONCLUSION:
In
this paper, the operation and control of a futuristic power distribution system
consisting of two radial feeders with one CPT replaced by an ST is presented.
It is shown that the ST can compensate for the loads connected at the feeder
supplied by the CPTs, in addition to supplying their own loads. This scheme has
potential to eliminate the requirement of power quality improvement devices
such as STATCOM, power factor correcting capacitors, etc., connected at the
second feeder. This ancillary feature in the medium voltage power distribution systems
has potential to make application of ST more attractive and cost effective.
REFERENCES:
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2012
IEEE,
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[3]
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