Download Fault Analysis on Maximum point Power Tracking based Grid

FAULT ANALYSIS ON MAXIMUM POINT POWER
TRACKING BASED GRID CONNECTED
PHOTOVOLTAIC SYSTEM
Guided By:-
Mr. Sibasish Panda
(Assistant Professor)
Presented By:1.
2.
3.
4.
5.
Mukesh Kumar Pandit(090101EER040)
Jyotiranjan Behera (0901213206)
Jagannath Mahapatra (0901213170)
Jyoti Ranjan Sahu (090101EER019)
Shiv Prasad Sahoo (090101EER007)
CONTENTS







Introduction
components of grid connected photovoltaic power system
Schematic Diagram of grid connected PV system
control of three phase grid connected PV system
Simulation and Result
Conclusion
References
INTRODUCTION
 As the world electricity consumption rapidly increases with
population growth, new power generation capacities are required to
cover that demand. So, there is need for power generation using
renewable sources. Hence Photovoltaic System is implemented to tie
with the power grid.
 In order to extract maximum power output from PV system
efficiently, MPPT technique is being used.
 A DC/DC converter used which tries to match the load impedance
to the ratio between voltage and current of the array at the
maximum power point (MPP).
 The converter used is a Voltage source inverter (VSI) which is
controlled using synchronous d-q reference frame to inject a
controlled current into the grid and Phase lock loop (PLL) is used
in controller to lock grid frequency and phase .
 Finally MPPT based Grid connected PV system was simulated
using SIMULINK and a fault study was conducted to examine the
behaviour of the system when the PV array was connected.
COMPONENTS OF GRID CONNECTED PV SYSTEM
Several components are needed to construct a grid connected PV
system to perform the power generation and conversion functions.
 Photovoltaic system
 DC-DC converter and Three-phase inverter
 LC filter
 Transformer
 Utility Grid
Figure 1: Components of a Grid Connected PV System
PHOTOVOLTAIC SYSTEM
Modeling of PV cell
I pv  I ph  I d  I Rp
Figure-2: Equivalent circuit diagram of PV cell
Figure-2 shows the equivalent circuit of the PVcell, formed by
a current source Iph in anti-parallel with diode driven by a
current Id.
From Figure -2 applying KCL
I pv  I ph  I d  I Rp
Finally, from the equivalent circuit of PV cell Ipv and Vpv are
I pv

 q  (V pv  I pv Rs )  
 N par  I ph  N par  I sat exp exp 
  1  (V pv  I pv Rs ) / R p
N s AkT

 

 I ph  I pv  I sat 
Vpv   I Rs  AVT ln ln 

I
sat


EFFECT OF IRRADIANCE
Figure 3: I-V characteristics of PV module under different irradiation level
Figure 4: P-V Characteristics of PV module under different irradiation level
EFFECT OF TEMPERATURE
Figure 5: I-V characteristics of PV module under different
temperature level
Figure 6: P-V characteristics of PV module under different temperature level
DC-DC BOOST CONVERTER
The boost DC converter is used to step up the input voltage by
storing energy in an inductor for a certain time period, and then
uses this energy to boost the input voltage to a higher value.
Figure 7: Circuit diagram of Boost Converter
The relationship between the input and output voltages is given by
Vinton  (Vin  Vout )toff  0
Vout ton  toff
1


Vin
toff
1 d
THREE-PHASE INVERTER
The three phase inverter is used to obtain a three-phase voltage output
from DC source. Three-phase voltage source inverter is a combination
of three single-phase bridge circuits.
Figure 8: Three-phase inverter
In grid connected PV system, the current output of the voltage source
inverter will be injected to the grid. The output of the inverter should
be in phase and have an identical frequency to the voltage of the grid.
SCHEMATIC DIAGRAM OF GRID CONNECTED
PV SYSTEM
Figure 9: Schematic diagram of grid connected PV system
CONTROL OF THREE PHASE GRID CONNECTED
PV SYSTEM
 The DC/DC boost converter is controlled using a maximum power
point tracking technique .
 For inverter control system dq transformation and SVPWM
technique are being used.
 Grid synchronizations plays important role for grid connected
systems. PLL technique is employed to synchronise the output
frequency and phase of grid voltage with inverter voltage using
different transformation.
MAXIMUM POWER POINT TRACKING
As the amount of power produced by the PV module varies greatly
depending on its operating conditions (temperature and
irradiation). Hence, there is need to constantly track the power
curve and keeps the solar panel operating voltage at the point
where the most power extracted. This process is known as
maximum power point tracking.
Figure 10: I-V & P-V curve at maximum power point
Description of Perturb-and-Observe Algorithm
Figure-11: Flow Chart of perturb and observe algorithm
abc/dq TRANSFORMATION
The dq transformation is used to transform three phase system
quantities like voltages and currents from the synchronous reference
frame (abc) to a synchronously rotating reference frame with three
constant components when the system is balanced. The relationship
that govern the transformation from the abc to dq frame is
 fd 
 fa 
 f  T  f 
 q
 b
 f 0 
 f c 
Where f can be either a set of three voltage or current to be transformed
T is the transformation matrix
The direct and quadrature components of the inverter output current
can be used to control the active and reactive output powers from the
PV array system
SVPWM TECHNIQUE
The space vector PWM (SVM) method is an advanced,
computation-intensive PWM method .
space vector PWM can be implemented by the following steps
Step 1. Determine Vd, Vq, Vref, and angle (α)
Step 2. Determine time duration T1, T2, T0
Step 3. Determine the switching time of each transistor (S1 to S6)

1

V
 d 2
V   
 q  3 0


V ref 
  tan
1
1
2
3
2

1 
Van 

2 
 Vbn 

3


Vcn 


2 

Vd2  Vq2
tan
1
Vq
Vd
 t  2 f
where f = fundamental frequency.
PHASE LOCKED LOOP TECHNIQUE
The role of the phase locked loop is to provide the rotation
frequency, direct and quadrature voltage components at the point of
common coupling (PCC) by resolving the grid voltage abc
components.
Figure 12: Schematic diagram of the phase locked loop (PLL)
  K pVq  Ki Vq dt
   dt
where  is rotation frequency in rad/s
 is rotation angle in radians
PLL SIMULINK MODEL
Figure 13 :Simulink model of PLL
VSI CONTROLLER SIMULINK MODEL
Figure 14 :Simulink model of VSI controller
SIMULATION MODEL OF GRID CONNECTED PV SYSTEM
Figure 15: Simulink Model of Grid Connected PV System
Voltage, Current and Power Output of PV array without MPPT
Voltage, Current and Power Output of Boost Converter with MPPT
FAULT ANALYSIS
Without Fault
LG Fault
LL Fault
LLG Fault
LLL Fault
LLLG Fault
WITHOUT FAULT
GRID VOLTAGE & CURRENT WAVEFORMS
P-Q WAVEFORMS
INVERTER VOLTAGE & CURRENT WAVEFORMS
THD FOR GRID VOLTAGE IN PHASE A
THD FOR GRID CURRENT IN PHASE A
THD FOR INVERTER VOLTAGE IN PHASE A
THD FOR INVERTER CURRENT IN PHASE A
LG FAULT
Grid Voltage & Current Waveforms
P-Q WAVEFORMS
INVERTER VOLTAGE WAVEFORM
THD FOR GRID VOLTAGE IN PHASE A
THD FOR GRID CURRENT IN PHASE A
THD FOR INVERTER VOLTAGE IN PHASE A
THD FOR INVERTER CURRENT IN PHASE A
LL FAULT
GRID VOLTAGE & CURRENT WAVEFORMS
P-Q WAVEFORMS
INVERTER VOLTAGE WAVEFORM
THD FOR GRID VOLTAGE IN PHASE A
THD FOR GRID CURRENT IN PHASE A
THD FOR INVERTER VOLTAGE IN PHASE A
THD FOR INVERTER CURRENT IN PHASE A
LLG FAULT
GRID VOLTAGE & CURRENT WAVEFORMS
P-Q WAVEFORMS
INVERTER VOLTAGE WAVEFORM
THD FOR GRID VOLTAGE IN PHASE A
THD FOR GRID CURRENT IN PHASE A
THD FOR INVERTER VOLTAGE IN PHASE A
THD FOR INVERTER CURRENT IN PHASE A
LLL FAULT
GRID VOLTAGE & CURRENT WAVEFORMS
P-Q WAVEFORMS
INVERTER VOLTAGE WAVEFORM
THD FOR GRID VOLTAGE IN PHASE A
THD FOR GRID CURRENT IN PHASE A
THD FOR INVERTER VOLTAGE IN PHASE A
THD FOR INVERTER CURRENT IN PHASE A
LLLG FAULT
GRID VOLTAGE & CURRENT WAVEFORMS
P-Q WAVEFORMS
INVERTER VOLTAGE WAVEFORM
THD FOR GRID VOLTAGE IN PHASE A
THD FOR GRID CURRENT IN PHASE A
THD FOR INVERTER VOLTAGE IN PHASE A
THD FOR INVERTER CURRENT IN PHASE A
Comparison of THDs for Grid side and Inverter side for various faults
Parameters
Voltage
Current
Type of fault
Inverter Side THD
(phase A) with filter
(in %)
Grid Side THD
(phase A)
(in %)
Without Fault
0.0
0.0
LG
LLG
LL
LLL
LLLG
Without Fault
LG
LLG
LL
LLL
LLLG
0.04
0.12
0.22
0.04
0.10
0.0
0.07
0.06
0.23
0.23
0.20
0.44
0.41
1.04
0.23
0.22
0.0
1.08
1.09
3.65
0.71
0.67
CONCLUSION
 First of all design of PV module is done using simulink .Then
Maximum power point tracking (P&O) algorithm was implemented
which aimed at tracking the maximum power from the PV array.
 At maximum power point, P&O technique perturbs the duty cycle of a
DC converter to check for power variations.
 After that 260V DC output voltage converted into AC using three
phase Inverter and the design of a control system for three phase grid
connected PV array was done using simulink.
 Finally, a fault study was conducted to assess the impact of the grid
connected PV system.
REFERENCES
• International Energy Agency (IEA)-PVPS. (2011, Sept.). Trends in
photovoltaic applications. [Online]. Available: www.iea-pvps.org
• Tarak Salmi, Mounir Bouzguenda, Adel Gastli, Ahmed Masmoudi,
“MATLAB/Simulink Based Modelling of Solar Photovoltaic Cell” ,
International Journal Of Renewable Energy Research Tarak Salmi et al.,
Vol.2, No.2, 2012.
• Trishan Esram, and Patrick L. Chapman, “Comparison of Photovoltaic
Array Maximum Power Point Tracking Techniques” IEEE Transactions
on Energy Conversion, Vol. 22, No. 2, June 2007.
• K. Manohar, P. Sobha Rani, “MPPT and Simulation for a GridConnected Photovoltaic System and Fault Analysis”, The International
Journal of Engineering And Science (IJES), Volume1; Issue 2, Pages
158-166; 2012.
• Xiao-Qiang GUO, Wei-Yang WU, He-Rong GU, “Phase locked loop
and synchronization methods for grid-interfaced converters: a review”,
PRZEGLĄD ELEKTROTECHNICZNY (Electrical Review), 2011.