Distributed Photovoltaic Generation Emulation in Converter Based Power Grid Emulation System Anthony...

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Distributed Photovoltaic Generation Emulation in Converter Based Power Grid Emulation System Anthony Perez, Mitchell Smith, Wenchao Cao, Dr. Fred Wang Final Presentation July 17, 2014 Knoxville, Tennessee

Transcript of Distributed Photovoltaic Generation Emulation in Converter Based Power Grid Emulation System Anthony...

Page 1: Distributed Photovoltaic Generation Emulation in Converter Based Power Grid Emulation System Anthony Perez, Mitchell Smith, Wenchao Cao, Dr. Fred Wang.

Distributed Photovoltaic Generation Emulation in Converter Based Power

Grid Emulation System

Anthony Perez,

Mitchell Smith, Wenchao Cao, Dr. Fred WangFinal Presentation

July 17, 2014

Knoxville, Tennessee

Page 2: Distributed Photovoltaic Generation Emulation in Converter Based Power Grid Emulation System Anthony Perez, Mitchell Smith, Wenchao Cao, Dr. Fred Wang.

Outline

• Objective and Approach

• Emulation Structure of HTB Converters

• Distributed Photovoltaic Model

• Future Work

Page 3: Distributed Photovoltaic Generation Emulation in Converter Based Power Grid Emulation System Anthony Perez, Mitchell Smith, Wenchao Cao, Dr. Fred Wang.

Objective and Approach

1. Use one converter to emulate one PV unit.

2. Use two converters to emulate two PV units.

3. Use one converter to emulate a radial distribution line with two PV units.

Objective: To emulate a distribution feeder with two PV units

Physical components of two stage PV inverter system

One inverter with PV model

Page 4: Distributed Photovoltaic Generation Emulation in Converter Based Power Grid Emulation System Anthony Perez, Mitchell Smith, Wenchao Cao, Dr. Fred Wang.

Hardware Test Bed

Page 5: Distributed Photovoltaic Generation Emulation in Converter Based Power Grid Emulation System Anthony Perez, Mitchell Smith, Wenchao Cao, Dr. Fred Wang.

Two-Area System Topology

Page 6: Distributed Photovoltaic Generation Emulation in Converter Based Power Grid Emulation System Anthony Perez, Mitchell Smith, Wenchao Cao, Dr. Fred Wang.

Simulations of Two-Area System

Page 7: Distributed Photovoltaic Generation Emulation in Converter Based Power Grid Emulation System Anthony Perez, Mitchell Smith, Wenchao Cao, Dr. Fred Wang.

Emulation Structure of HTB Converters

Functionality:

1. Current and voltage are measured.

2. Voltage’s value goes to the PV model to generate the current reference.

3. Current’s value goes to a current control loop to generate the signals to the inerter.

Page 8: Distributed Photovoltaic Generation Emulation in Converter Based Power Grid Emulation System Anthony Perez, Mitchell Smith, Wenchao Cao, Dr. Fred Wang.

Single Inverter System

Page 9: Distributed Photovoltaic Generation Emulation in Converter Based Power Grid Emulation System Anthony Perez, Mitchell Smith, Wenchao Cao, Dr. Fred Wang.

Single Inverter System Control (Simulink)

Distributed PV model

Current control

Page 10: Distributed Photovoltaic Generation Emulation in Converter Based Power Grid Emulation System Anthony Perez, Mitchell Smith, Wenchao Cao, Dr. Fred Wang.

Current Control Testing

Different testing have been done to test if the simulation has been well implemented.

The different testing are:

1. Id & Iq current control2. P & Q control

Active Current test

Reactive Current test

A step function was used for this test.

-For Id: a)Step time – 0.2 s b)Range – 0 to 0.5 pu

-For Iq: a)Step time – 0.2s b)Range - 0 to 0.2 pu

Page 11: Distributed Photovoltaic Generation Emulation in Converter Based Power Grid Emulation System Anthony Perez, Mitchell Smith, Wenchao Cao, Dr. Fred Wang.

P & Q Control

P and Q response when a step change is apply as a reference.

For Q: Step time – 0.2 s Range - 0 to 0.1 pu

For P: Step time – 0.2 s Range – 0 to 1pu

Page 12: Distributed Photovoltaic Generation Emulation in Converter Based Power Grid Emulation System Anthony Perez, Mitchell Smith, Wenchao Cao, Dr. Fred Wang.

Distributed Photovoltaic Model

Physical components of two stage PV inverter system

One inverter with PV model

Distributed PV model

PV panel model

Page 13: Distributed Photovoltaic Generation Emulation in Converter Based Power Grid Emulation System Anthony Perez, Mitchell Smith, Wenchao Cao, Dr. Fred Wang.

Distributed Photovoltaic System Model (Simulink)

5-13

Sub part 1:PV panel model

Sub part 2: System control model

Page 14: Distributed Photovoltaic Generation Emulation in Converter Based Power Grid Emulation System Anthony Perez, Mitchell Smith, Wenchao Cao, Dr. Fred Wang.

Sub part 1: PV Panel Model

5-14

S: solar irradiance (W/m2)T: temperature (deg C)Pmax: Maximum power outputSingle diode model

stcVopstcIsc

VocIscstcPmpP

___max

Simulation model of PV panel

Page 15: Distributed Photovoltaic Generation Emulation in Converter Based Power Grid Emulation System Anthony Perez, Mitchell Smith, Wenchao Cao, Dr. Fred Wang.

Simulation of PV Panel Model

• 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.

0 10 20 30 40 500

2

4

6I - V curve with irradiance changes (T = 25 C)

Voltage (V)

Cu

rre

nt (

Am

ps)

S = 600 W/m2

S = 800 W/m2

S = 1000 W/m2

0 10 20 30 40 500

2

4

6

Voltage (V)

Cu

rre

nt (

Am

ps)

I - V curve for temperature variations (S = 1000 W/m2)

T = 25 C

T = 45 C

T = 60 C

0.2 0.4 0.6 0.8 1 1.225

30

35

Time (s)

T (

C)

0.2 0.4 0.6 0.8 1 1.2600

800

1000

Time (s)

S (

W/m

2 )

0.2 0.4 0.6 0.8 1 1.20

0.5

1

Time (s)

Po

we

r (p

u)

Pmax

Q

Page 16: Distributed Photovoltaic Generation Emulation in Converter Based Power Grid Emulation System Anthony Perez, Mitchell Smith, Wenchao Cao, Dr. Fred Wang.

Sub part 2: DPVS Control Model

Ref. http://www.powerworld.com/files/WECC-Solar-PV-Dynamic-Model-Specification-September-2012.pdf [Western Electricity Coordinating Council]

Q-V droop control

P-f droop control

Page 17: Distributed Photovoltaic Generation Emulation in Converter Based Power Grid Emulation System Anthony Perez, Mitchell Smith, Wenchao Cao, Dr. Fred Wang.

DPVS Control Model (Simulink)

P-f droop control

Q-V droop control

Page 18: Distributed Photovoltaic Generation Emulation in Converter Based Power Grid Emulation System Anthony Perez, Mitchell Smith, Wenchao Cao, Dr. Fred Wang.

P & Freq. Droop

-A ramp function was used for this test.

-For freq: slope – 0.5 a)starting time – 0 b)initial output - 60

- Dead-band: 0.05 Hz

Note: The frequency of the constant source is modify to have an step change of 0.3 in 0.5 and 0. 8 s.

0 0.2 0.4 0.6 0.8 1-0.5

00.5

11.5

Time (s)Act

ive

Po

we

r (p

u)

0 0.2 0.4 0.6 0.8 160

60.260.460.660.8

Time (s)

Fre

qu

en

cy (

Hz)

Page 19: Distributed Photovoltaic Generation Emulation in Converter Based Power Grid Emulation System Anthony Perez, Mitchell Smith, Wenchao Cao, Dr. Fred Wang.

Q & V Droop

-A ramp function was used for this test.

-For freq: slope – 0.2 a)starting time – 0 b)initial output – 0.9

- Dead-band: 0.02 pu

Note: The amplitude of the constant source is modify to change from 1 to 1.1 and 0.9 pu in 0, 0.5 and 0. 8 s respectively.

0 0.2 0.4 0.6 0.8 1-0.3-0.2-0.1

00.10.20.3

Time (s)

Re

act

ive

Po

we

r (p

u)

0 0.2 0.4 0.6 0.8 10.80.9

11.11.2

Time (s)

Vo

ltag

e (

pu

)

Page 20: Distributed Photovoltaic Generation Emulation in Converter Based Power Grid Emulation System Anthony Perez, Mitchell Smith, Wenchao Cao, Dr. Fred Wang.

System Response with Q & V and P & f Implementation

Reactive Power and terminal voltage waves when the voltage change from 1 to 1.1 pu in 0.5 seconds and to 0.9 pu in 0.8 seconds.

0.1 0.3 0.5 0.7 0.9 1.1 1.2-0.5-0.3-0.10.10.30.5

Time (s)

Q (

pu

)

0.2 0.4 0.6 0.8 1 1.21.20

0.5

1

1.5

Time (s)

Vo

ltag

e (

pu

)

0 0.2 0.4 0.6 0.8 1 1.2

0.2

0.4

0.6

0.8

Time (s)P

(p

u)

0 0.2 0.4 0.6 0.8 1 1.2

60

60.1

60.2

Time (s)

Fre

qu

en

cy (

Hz)

Active power and frequency Waveforms when the frequency it is changed by .3 Hz in .5 and .8 second respectively

Page 21: Distributed Photovoltaic Generation Emulation in Converter Based Power Grid Emulation System Anthony Perez, Mitchell Smith, Wenchao Cao, Dr. Fred Wang.

Two PV Unit System SimulationA distribution feeder with two PV units

PV 1

PV 2

Page 22: Distributed Photovoltaic Generation Emulation in Converter Based Power Grid Emulation System Anthony Perez, Mitchell Smith, Wenchao Cao, Dr. Fred Wang.

Two PV Inverter System Simulation

0.2 0.4 0.6 0.8 1 1.20.9

0.95

1

Time (s)

V (

pu

)

0.2 0.4 0.6 0.8 1 1.2

0

1

2

3

x 104

P (

W)

Q(V

ar)

Time (s)0.2 0.4 0.6 0.8 1 1.2

0

1

2

3

x 104

Time (s)

P (

W)

Q(V

ar)

0.2 0.4 0.6 0.8 1 1.2

0.96

0.98

1

1.02

Time (s)

V (

pu

)

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.

Without Q-V droop With Q-V droop

Q1, Q2

P1, P2

V1

V2

Q1, Q2

V1

V2

P1, P2

Page 23: Distributed Photovoltaic Generation Emulation in Converter Based Power Grid Emulation System Anthony Perez, Mitchell Smith, Wenchao Cao, Dr. Fred Wang.

Conclusions & 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.

Page 24: Distributed Photovoltaic Generation Emulation in Converter Based Power Grid Emulation System Anthony Perez, Mitchell Smith, Wenchao Cao, Dr. Fred Wang.

Questions?