Download Grid and DG connected mode

DG VOLTAGE CONTROL IN AN ISLANDING
MODE OF OPERATION
CHANDANA BOMMAREDDY
CLEMSON UNIVERSITY
Clemson University Electric Power Research Association
Presentation Outline
•
Purpose of the presentation
•
Distributed Generation and the increasing interest in distributed resources
•
Grid-connected and stand-alone modes of operation
•
Simulation of an IEEE bus feeder using PSCAD
•
Simulation of synchronous generator using PSCAD
•
Simulation of induction generator using PSCAD
•
To study their impact on the voltage in both the modes and compare the results
•
Conclusion and future work
Clemson University Electric Power Research Association
Purpose of the Presentation
•
Operation of distributed generation systems (DGS) in a standalone AC power
supply
•
Voltage fluctuations due to many reasons
•
Distribution networks and voltage stability
•
Control voltage and frequency to the improvement of the power quality
Clemson University Electric Power Research Association
Distributed Generation
Why is Distributed Generation so popular ?
•
Speed & mobility
•
Higher efficiencies than centralized generation
•
Reliability of power
•
Flexibility & choice to consumers
•
Reduction of transmission and distribution costs
•
Suited for small-scale generation in the commercial and industrial
sectors
Clemson University Electric Power Research Association
Distributed Generation Technologies
Considering only the electrical characteristics there are three different DG types:
•
Synchronous generator
•
Asynchronous generator
•
Photo Voltaic
•
Other
Clemson University Electric Power Research Association
Different modes of operation
GRID
4.16 kV
•
DG
4.16 / 0.48 kV
LOAD
480V, 1.5 MW
Grid-connected mode
The utility is used as reference for voltage and frequency. DG is
assumed to be disconnected from the grid in this mode of operation.
•
Grid and DG connected mode
DG is assumed to be connected and operating in parallel with the grid
in this mode of operation.
•
Stand-alone mode
The DG is disconnected from the grid and is its in maximum mode
of operation
Clemson University Electric Power Research Association
Modeling of power system components
IEEE 13 Node Test Feeder
650
646
645
611
684
652
Clemson University Electric Power Research Association
632
671
680
633
692
634
675
Simulation of synchronous generator
Exciter (SCRX)
Vref
Vabc
Ef
If
Tmi
Multimass
( SyncM/c)
Tm Te Wrad
1.0
1.0
3 Phase
RMS
Ef If
w
Sync1
Te
Tm
w Tm
Tm0 w Tm
SP Hydro
Governor
Clemson University Electric Power Research Association
A
A
B
B
C
C
Simulation of induction generator
3 Phase
RMS
1.01
StoT
W
Motor
S 1
0
T
A
A
B
B
C
C
TS
2100.0
2100.0
2100.0
Clemson University Electric Power Research Association
Results and Discussions
Grid-connected mode with and without capacitors
Clemson University Electric Power Research Association
Grid and DG mode
Synchronous Generator with and without capacitor
Clemson University Electric Power Research Association
Induction Generator with and without capacitor
Clemson University Electric Power Research Association
Stand-alone mode
Synchronous Generator
Clemson University Electric Power Research Association
Induction Generator
CONCLUSIONS
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The steady state models developed, simulate the operation of synchronous
generator and induction generator in the stand-alone and grid-connected
modes.
•
Both the models were used to study the comparison of voltage magnitudes
in the two different modes of operation of the DG.
•
Results show the voltage magnitudes dropped significantly in the standalone mode.
•
Capacitors connected at selected buses improved the voltage magnitudes by
3 - 6% which is a considerable increase.
•
Original capacitors in the grid-connected mode may not help the islanding
mode of operation.
Clemson University Electric Power Research Association
FUTURE WORK
I.
Develop the following control mechanisms to control the voltage in the
stand-alone mode of operation at 60 Hz :
a)
Synchronous Condenser
Static VAR Compensator
Tap Changing Transformers
Voltage Regulator
Other
b)
c)
d)
e)
II.
Develop detailed models of some DG control methods that are
described in Part I to control harmonics due :
a)
Non linear loads
DG model
b)
Clemson University Electric Power Research Association
QUESTIONS ?
THANK YOU
Clemson University Electric Power Research Association