Transcript REU Poster - CURENT Education

Distributed Photovoltaic Generation Emulation in
Converter Based Power Grid Emulation System
Anthony Perez1, Wenchao Cao2, Mitchell Smith2, Dr. Fred Wang2
1 University of Puerto Rico, Mayaguez, 2 University of Tennessee
Motivations
Single PV Inverter System Simulation
Natural conditions variations like temperature and solar
irradiance are considered in this work, to see the impacts
in the system and to obtain more realistic results.
I - V curve with irradiance changes (T = 25 C)
6
T (C)
4
25
0.2
S = 600 W/m
2
20
30
Voltage (V)
40
50
T = 25 C
T = 45 C
T = 60 C
2
10
20
30
Voltage (V)
40
1.2
600
0.2
0.4
0.6
0.8
Time (s)
1
1.2
1
Pmax
Q
0.5
0
0.2
0.4
0.6
0.8
Time (s)
50
1
1.2
System response after P-f and
Q-V droop implementation
P (pu)
0.8
0.2
60.8
60.6
60.4
60.2
60
0
0.4
0.6
Time (s)
0.2
0.3
0.2
0.1
0
-0.1
-0.2
-0.3
0
0.8
0.4
0.6
Time (s)
0.8
1
0.4
0
0.8
1
1.2
1.1
1
0.9
0.8
0
0.2
0.4
0.6
Time (s)
0.8
0.4
0.6
Time (s)
0.8
1
1.2
0.2
0.4
0.6
Time (s)
0.8
1
1.2
60.1
60
0
0.4
0.6
Time (s)
0.2
60.2
0.5
0.3
0.1
-0.1
-0.3
-0.5
0.1
Voltage (pu)
0.2
0.6
0.2
1
Q (pu)
Frequency (Hz) Active Power (pu)
1.5
1
0.5
0
-0.5
0
Voltage (pu) Reactive Power (pu)
Diagram of distributed PV model
1
800
Power (pu)
Current (Amps)
4
S (W/m 2)
10
P-f and Q-V droop testing
Emulation structure of HTB converters
0.6
0.8
Time (s)
1000
2
S = 1000 W/m
0
0
• The dynamic model of the photovoltaic panels were
implemented with a Maximum Power Point Tracking control
system to output the maximum power of the PV system.
• To emulate this system the Hardware Test Bed (HTB) is
used.
• HTB is a reconfigurable structure that can emulate a large
scale power system.
• HTB uses some reprogrammable converters to emulate
different components of the power system like: generators,
loads and transmission lines.
0.4
2
S = 800 W/m
I - V curve for temperature variations (S = 1000 W/m 2)
6
• For this work, two photovoltaic systems connected at the
distribution level were selected.
30
2
0
0
Methods
35
Frequency (Hz)
Current (Amps)
• Emulate photovoltaic panels (PV) without using the actual
physical component.
• Investigate the impact of distributed photovoltaic systems
(DPVS) penetration using the Hardware Tesbed (HTB)
configuration.
• Be able to emulate one PV in one converter and then
emulate two photovoltaic systems in one converter.
Results
0.3
0.5
0.7
Time (s)
0.9
1.1 1.2
1.5
1
0.5
0
1
0.2
0.4
0.6
0.8
Time (s)
1
1.2
Two PV Inverter System Simulation
4
Without Q-V droop
x 10
P (W) Q(Var)
x 10
P (W) Q(Var)
• In order to emulate a photovoltaic system into the HTB it is
necessary to design the control functions that will manage
the converter.
• This control functions involve P-freq. and Q-V droop
functions to maintain the balance in the system.
To verify the effects of the droop function implementation into
the two PV models, it is shown in the graphs below. The
reactive power and terminal voltage changes at the terminal
of each PV system.
3
P1, P2
Q1, Q2
2
1
0
0.2
0.4
0.6
0.8
Time (s)
1
1
0.2
V (pu)
V (pu)
V2
0.6
0.8
Time (s)
P1, P2
Q1, Q2
2
0.4
1.02
0.95
0.4
3
1.2
V1
0.2
With Q-V droop
0
1
0.9
4
0.6
0.8
Time (s)
1
1.2
1
V1
0.98
0.96
1
1.2
0.2
0.4
0.6
0.8
Time (s)
1
1.2
V2
Conclusions and Future Work
• A converter based distributed PV emulator with variable
irradiance and temperature is designed.
• Different control strategies for the DPVS were implemented
in order to maintain the balance in the power grid.
• The implementation of this system into the real HTB
configuration is required for future work.
This work was supported primarily by the Engineering Research Center
Program of the National Science Foundation and the Department of
Energy under NSF Award Number EEC-1041877 and the CURENT
Industry Partnership Program.