DOI : 10.17577/IJERTV5IS100097
- Open Access
- Total Downloads : 292
- Authors : Kiran Karibasappa Sunagar, B. D Ballullya, Sandeep Kudal, Vrutha Puthran
- Paper ID : IJERTV5IS100097
- Volume & Issue : Volume 05, Issue 10 (October 2016)
- DOI : http://dx.doi.org/10.17577/IJERTV5IS100097
- Published (First Online): 08-10-2016
- ISSN (Online) : 2278-0181
- Publisher Name : IJERT
- License:
This work is licensed under a Creative Commons Attribution 4.0 International License
Analysis of Fault Ride through Capabilities in Wind Plants using STATCOM and UPFC-A Case Study
B. D Ballullya2,
2Professor,
Power System Engineering Department, SDMCET, Dharwad
Kiran Karibasappa Sunagar 1, Sandeep Kudal3, Vrutha Puthran4
1, 3, 4PG students,
Power System Engineering Department, SDMCET, Dharwad
AbstractVoltage dip is one of the major concerns related to quality of power in power system. The main objective of this paper is to analyze the stability issues related to wind plant connected to grid. The work flow goes in order by collection of real time data, study of existing methods employed to improve power quality enhancement of wind plant connected to grid. The wind plant connected to grid and the use of FACTS controller such as STATCOM and UPFC controller with consideration of their design and control levels, a grid interactive wind plant model is built using MATLAB/SIMULINK model.
The developed SIMULINK model is studied for steady state analysis of reactive power compensation and voltage variation in wind plant. The system is analyzed with and without STATCOM and UPFC controller for different condition to study voltage variation and reactive power support.
Keywords Cerc,Facts,Statcom,Upfc.
-
INTRODUCTION
The technical development and sophistication life style has increased the use of electricity. The growing demand of electricity, depletion of fossil fuels, global warming has been a concern. This has led to generate electricity using green energy which is gaining a momentum all over the world. Hence, low cost and reliable low carbon electricity generation has been given much attention in many countries. Wind plant which is a green energy has large penetration into the power system network and wind grid penetration is expected to be 20 percent by 2030.This major increase in the capacity of wind energy in power system may affect the grid performance.
Grid interactive wind plants are susceptible to the faults caused by lightning, failure of insulation, generation and load pattern in deregulated power system network, contingency and increase in loading of transmission line. These can lead to voltage dip due to increased consumption of reactive power in the power system. So the reactive power support during faulted conditions to wind plant is necessary and it must be fulfilled by wind plants connected to grid as per CERC grid codes.
-
FAULT RIDE THROUGH CAPABILITY
REQUIREMENT
The Central Electricity Regulatory Authority of India has issued connectivity standards of wind plant interconnection to grid according to which wind plants should have fault ride through capability.ie at the point of common coupling whenever there is voltage dip on any phase up to 15% of its
nominal voltage, wind plant should be able to remain connected to grid during this fault condition till the period of 300ms or when voltage starts recovering. This requirement during faulted condition needs external reactive power support using external reactive power source using FACTS device [1]. Thus, FACTS controller can be opted to mitigate the effects of voltage dip at the point of common coupling for wind plant connected to grid and also provide reactive power support to the wind plant which in turn fulfills fault ride through capability.
Fig. 1.Fault Ride Through Capability Profile
Vf – 15% of nominal system voltage.
Vpf – minimum voltage
-
SYSTEM UNDER STUDY
A case study system has 24 wind turbines. Analysis and simulation of the same is carried out in this work. Each unit is connected with 1.6 MVA 400V/33kV step-up transformer; units are grouped in 6 rows and fed by separate inter-farm lines up to pooling station. From pooling station generated power will be transmitted via 33/220kV 30MVA Power Transformer and a 220kV line for a distance of about 18kms up Substation.
Fig. 2.Schematic diagram of system under study.
The electrical power generated by wind turbine is given by the following expression P=0.53…………………………………………………… [1.1]
Where
P – Power in watts.
– Air density (standard air density is 1.2 kg/ m³). A- Area Swept by turbine blades in m².
V- Wind speed in meter/second.
-
STATIC SYNCHRONOUS COMPENSATOR
A STATCOM is a controlled shunt connected reactive power source. By processing voltage and current waveforms in voltage source converter, a required generation and absorption of reactive power to the system to which it is connected is done. The design is compact since it is an adjustable voltage source behind a reactance. It indicates that reactive power generation and absorption do not need capacitor bank and reactors [2].
Fig. 3.Equivalent diagram of STATCOM
A STATCOM is a controlled reactive power source as its voltage can be controlled to desired output. The STATCOM consists of voltage source converter and it is connected to bus through shunt transformer as shown in figure 3.
In block diagram we can observe Vac – Bus Voltage
Iac- STATCOM Injected Current Vout- VSC output voltage
Vdc -DC side voltage Idc- Dc side current
Fig. 4.Schematic representation of STATCOM.
The VSC consists of IGBT with a back to back diode which indicates three arm IGBT bridge present in voltage source converter and voltage source converter has two operations[4]
-
Inverter operation- when IGBT conducts.
-
Converter operation when Diode conducts.
A STATCOM power exchange characteristics is shown in figure below and by controlling Vout of the converter we can control the exchange of reactive power
between converter and ac system to which it is connected. If the amplitude of Vout is greater than Vac then reactive current flows from converter to the AC system i.e. reactive power flows from converter to AC system. When amplitude of Vout is less than Vac then the reactive power flows from AC system to converter [3].
Fig. 5.VI characteristic of STATCOM
Fig. 6.Power Exchange Characteristic
The STATCOM control strategy consists of
-
PHASE LOCK LOOP: It synchronizes the positive sequence component of three phase primary voltage V1.The output of phase lock loop is used in computing D axis and Q axis components of three phase voltage and currents.
-
AC and DC REGULATOR: The AC regulator generates reference current for current regulator. Likewise DC regulator generates reference current for current regulator.
-
PULSE WIDTH MODULATION: It is used to generate gate pulses for IGBT of voltage source converter. It generates a sine wave of 50 Hz and a triangular wave of 20 kHz where both waves are compared to produce gate pulses which are in turn given as gate pulses to IGBT.
-
CURRENT REGULATOR: The reference current
generated AC and DC regulator are used by current regulator to control magnitude and phase of the voltage generated by pulse width modulation converter.
-
-
UNIFIED POWER FLOW CONTROLLER
Unified power flow controller is a shunt series FACTS controller which is more versatile controller used to regulate voltage and power flows. The unified power flow
controller is shunt series FACTS controller since it is combination of static synchronous compensator and static synchronous series compensator which are interconnected by a common DC capacitor. The UPFC has most fast response and decoupled active and reactive power compensations to connected system [5].
Fig. 7.Schematic representation o UPFC.
The UPFC control strategy consists of two converters i.e. STATCOM and SSSC converter the control strategy for statcom is same as explained in earlier section. In overall statcom performs control of AC voltage at it terminals and voltage of DC bus using inner current loop and outer loop. SSSC control scheme as shown in figure 8 can operate in two modes i.e. automatic mode and manual mode. In automatic mode power control is done by comparing measured values of active and reactive power with reference values to produce active and reactive power errors. The active and reactive power errors are used by PI controller to compute Vq and Vd components of voltage to be synthesized by the VSC.In manual mode reference values of injected voltage Vdref and Vqref are used to produce converter voltage[6].
Fig. 8.Schematic representation of control strategy STATCOM.
-
PERFORMANCE ANALYSIS OF CASE STUDY SYSTEM
The simulation of the system has been performed using the Simulink tool of MATLAB software.
-
Matlab/Simulink model of DFIG Wind plant with STATCOM for different conditions
Fig. 9.Matlab/Simulink model of DFIG Wind plant with STATCOM. CASE 1: NO LOAD CONDITION
TABLE I
NO LOAD CONDITION
33kV BUS VALUES
WITHOUT STATCOM
WITH STATCOM
T(S)
V (PU)
P (MW)
Q (MVAR)
V (PU)
P (MW)
Q (MVAR)
5
0.96
– 0.8
0.7
0.97
– 0.8
5.5
10
0.90
19.2
6.5
0.92
19.2
10.2
CASE 2: LOAD CONDITION -10 MW
TABLE II LOAD CONDITION
33kV BUS VALUES
WITHOUT STATCOM
WITH STATCOM
T(S)
V (PU)
P (MW)
Q (MVAR)
V (PU)
P (MW)
Q (MVAR)
5
0.93
– 0.8
0.6
0.95
0.12
4
10
0.89
19.2
6.4
0.92
19.2
10.5
CASE 3: OVERLOAD CONDITION 30MW
TABLE III OVERLOAD CONDITION
33kV BUS VALUES
WITHOUT STATCOM
WITH STATCOM
T(S)
V (PU)
P (MW)
Q (MVAR)
V (PU)
P (MW)
Q (MVAR)
2.5
0.42
-2.5
0.95
0.64
4.9
1.2
5
0.45
3.2
1.2
0.51
8.8
3.9
CASE 4: FAULT CONDITION
TABLE IV
CASE 3: OVER LOAD CONDITION 10MW
TABLE VII
33KV BUS VALUES
WITHOUT STATCOM
WITH STATCOM
T(S)
V (PU)
P (MW)
Q (MVAR)
V (PU)
P (MW)
Q (MVAR)
2.5
0.4
-8
0.6
0.8
-2.5
1.2
5
0.6
-1.5
0.8
0.92
6
1.3
33KV BUS VALUES
WITHOUT STATCOM
WITH STATCOM
T(S)
V (PU)
P (MW)
Q (MVAR)
V (PU)
P (MW)
Q (MVAR)
2.5
0.4
-8
0.6
0.8
-2.5
1.2
5
0.6
-1.5
0.8
0.92
6
1.3
FAULT CONDITION
-
Matlab/Simulink model of DFIG Wind plant with UPFC for different conditions
OVER LOAD CONDITION
33kV BUS VALUES
WITHOUT UPFC
WITH UPFC
T(S)
V (PU)
P (MW)
Q (MVAR)
V (PU)
P (MW)
Q (MVAR)
2.5
0.42
-2.5
0.95
0.64
-0.16
0.92
5
0.45
3.2
1.2
0.6
9.7
4.2
CASE 4: OVER LOAD CONDITION 10MW
TABLE VIII FAULT CONDITION
33kV BUS VALUES
WITHOUT UPFC
WITH UPFC
T(S)
V (PU)
P (MW)
Q (MVAR)
V (PU)
P (MW)
Q (MVAR)
2.5
0.4
-8
0.6
0.82
-1.5
1.2
5
0.6
-1.5
0.8
0.97
7.2
2.1
-
-
COMPARISION OF PERFORMANCE OF STATCOM AND UPFC CASE 1: NO LOAD CONDITION
N0 LOAD CONDITION
25
PU,MW,MVAR,M/SEC
PU,MW,MVAR,M/SEC
20
15
10
5 0.9 0.920.94
0
19.2 19.219.2
10.2 10.6
6.5
12 12 12
Voltage Power Reactive power Wind speed
Fig. 10. Matlab/Simulink model of DFIG Wind plant with UPFC CASE 1: NO LOAD CONDITION
TABLE V
Without FACTS STATCOM
AT 10 SECONDS
NO LOAD CONDITION
33kV BUS VALUES
WITHOUT UPFC
WITH UPFC
T(S)
V (PU)
P (MW)
Q (MVAR)
V (PU)
P (MW)
Q (MVAR)
5
0.96
-0.8
0.7
0.98
1.2
4.6
10
0.90
19.2
6.5
0.94
19.2
10.6
CASE 2: LOAD CONDITION 10MW
TABLE VI LOAD CONDITION
33kV BUS VALUES
WITHOUT UPFC
WITH UPFC
T(S)
V (PU)
P (MW)
Q (MVAR)
V (PU)
P (MW)
Q (MVAR)
5
0.93
-0.8
0.6
0.96
0.15
4.5
10
0.89
19.2
6.4
0.94
19.2
11.2
Fig. 11. Voltage, power, Reactive power, wind speed in STATCOM and UPF.C at No load condition
GENERATED REACTIVE POWER AT NO LOAD
CONDITION
GENERATED REACTIVE POWER AT NO LOAD
CONDITION
3
2.5
2
1.5
1
0.5
0
2.6
3
2.5
2
1.5
1
0.5
0
2.6
2.1
2.1
0.96 0.97
0.96 0.97
STATCOM
UPFC
STATCOM
UPFC
Voltage
Voltage
Generated
Reactive Power
Generated
Reactive Power
AT 10 SECONDS
AT 10 SECONDS
.
.
PU,MVAR
PU,MVAR
Fig. 12. Generated reactive power in STATCOM and UPFC at No load condition
3
2.5
3
2.5
2.4
2.4
2.56
2.56
2
1.5
1
2
1.5
1
19.2 19.219.2
19.2 19.219.2
15
15
10.511.2
10.511.2
12 12 12
12 12 12
10
10
PU,MW,MVAR,M/SEC
PU,MW,MVAR,M/SEC
CASE 2: LOAD CONDITION -10MW
LOAD CONDITION
25
20
GENERATED REACTIVE POWER AT OVERLOAD
CONDITION
LOAD CONDITION
25
20
GENERATED REACTIVE POWER AT OVERLOAD
CONDITION
0.81 0.82
0.81 0.82
STATCOM
STATCOM
0.5
0.5
UPFC
UPFC
0
0
Voltage
Voltage
Generated Reactive
Power
Generated Reactive
Power
AT 5 SECONDS
AT 5 SECONDS
6.4
6.4
5
5
0.890.92 0.94
0.890.92 0.94
0
0
Voltage
Voltage
Power Reactive power Wind speed
AT 10 SECONDS
Power Reactive power Wind speed
AT 10 SECONDS
Without FACTS
STATCOM
UPFC
Without FACTS
STATCOM
UPFC
3
2.5
2
3
2.5
2
2.7
2.7
2.2
2.2
PU,MVAR
PU,MVAR
PU,MVAR
PU,MVAR
Fig. 13. Voltage, power, Reactive power, wind speed in STATCOM and UPFC at Load condition
GENERATED REACTIVE POWER AT LOAD
CONDITION
GENERATED REACTIVE POWER AT LOAD
CONDITION
AT 10 SECONDS
AT 10 SECONDS
UPFC
UPFC
1.5 0.95 0.97
1
0.5
0
Voltage Generated Reactive Power
1.5 0.95 0.97
1
0.5
0
Voltage Generated Reactive Power
STATCOM
STATCOM
Fig. 14. Generated reactive power in STATCOM and UPFC at Load
condition.
OVERLOAD CONDITION
OVERLOAD CONDITION
14
12
10
8
6
4
2
0
14
12
10
8
6
4
2
0
12 12 12
12 12 12
9.7
9.7
8.8
8.8
3.94.2
3.94.2
PU,MW,MVAR,M/SEC
PU,MW,MVAR,M/SEC
CASE 3: OVERLOAD CONDITION-30 MW
3.5
3.5
0.45 0.51 0.6
0.45 0.51 0.6
1.2
1.2
Voltage
Without FACTS STATCOM UPFC
Voltage
Without FACTS STATCOM UPFC
Power
Power
Reactive Wind speed
power
Reactive Wind speed
power
AT 5 SECONDS
AT 5 SECONDS
Fig. 15.Voltage, power, Reactive power, wind speed in STATCOM and
UPFC at overload condition.
Fig. 16. Generated reactive power in STATCOM and UPFC at overload
condition.
7.2
6
7.2
6
4
2
0
-2
-4
4
2
0
-2
-4
2.1
2.1
PU,MW,MVAR,M/SEC
PU,MW,MVAR,M/SEC
CASE 4: FAULT CONDITION
FAULT CONDITION
FAULT CONDITION
14
12
10
8
6
12 12 12
14
12
10
8
6
12 12 12
Without FACTS
STATCOM UPFC
AT 5 SECONDS
Without FACTS
STATCOM UPFC
AT 5 SECONDS
0.60.92
0.60.92
0.97
0.97
0.8 1.3
0.8 1.3
Voltage
Voltage
Power
-1.5
Power
-1.5
Reactive power Wind speed
Reactive power Wind speed
Fig. 17.Voltage, power, Reactive power, wind speed in STATCOM and
3.5
3
2.5
2
1.5
1
0.5
0
STATCOM
3.5
3
2.5
2
1.5
1
0.5
0
STATCOM
2.7
2.7
2.9
2.9
PU,MVAR
PU,MVAR
UPFC at Fault condition.
GENERATED REACTIVE POWER AT FAULT
CONDITION
GENERATED REACTIVE POWER AT FAULT
CONDITION
0.94 0.95
0.94 0.95
Voltage
Voltage
Generated Reactive Power
At 5 SECONDS
Generated Reactive Power
At 5 SECONDS
UPFC
UPFC
Fig. 18.Generated reactive power in STATCOM and UPFC at Fault condition.
-
CONCLUSION
This paper investigates the application of FACTS devices to improve the fault ride through capability of wind plants to meet the grid code. Results obtained show that without FACTS devices, wind plants will be disconnected from the grid due to voltage dip at the point of common coupling. The presence of FACTS devices will improve voltage, fault ride through capability of wind plants and with adequate reactive power support the connectivity of wind plants to grid is guaranteed.
The FACTS devices such as STATCOM and UPFC are used in this study to provide reactive power support which ensures improvements in power system stability and fulfilling requirements of grid code standards.
The results obtained by use of two FACTS devices STATCOM and UPFC show that UPFC has improved reactive power support, improved voltage profile and stability. Hence, the results obtained encourage using UPFC in wind plants connected to grid for improved reactive power support and voltage profile to enhance fault ride through capability to meet grid code standards.
Following inferences can be drawn from the results obtained through performance analysis of UPFC and STATCOM.
-
Improved voltage profile and reactive power at the bus as shown in graphs at different operating conditions shows that UPFC is better as compared to STATCOM.
-
The improvement in the Stability associated issues such as Power, rotor speed, pitch angle and reactive power shows that UPFC is better as compared to STATCOM.
-
At different operating conditions, voltage profile and reactive power support improvement by UPFC is better as compared to STATCOM.
At overload and fault condition without FACTS devices, the voltage dips at point of common coupling violates safety margins of grid codes. Application of FACTS to wind plant connected to grid at overload and fault condition improves voltage at point of common coupling. The presence of FACTS will improve fault ride through capability and hence wind plant connection to grid can be maintained by adequate reactive power support at overload and fault conditions using FACTS to ensure connectivity of wind plants to grid. From the results obtained at overload and fault condition with STATCOM and UPFC shows that UPFC has better performance as compared to STATCOM to maintain voltage and reactive power support. Hence presence of UPFC has better performance to ensure connectivity of wind plants to grid.
REFERENCES
-
Understanding FACTS- Concepts and Technology of AC Transmission Systems.IEEE Press- 1999, John Wiley and Sons, INC., Publication Narain G. Hingorani, Laszlo Gyugi.
-
Flexible AC Transmission System: A status review Sadhana, Vol. 22, Part 6, December 1997.Xi Yong; Liwei Zhang; Zhangjun Song; Ying Hu; LanZheng; Jianwei Zhang, 2011 IEEE International Conference on , vol., no., pp.390, 395, 6-8 June 2011 K. R. Padiyar, A. M. Kulkarni.
-
A review of grid code technical requirements for wind farms M. Tsili,S.Papathanassiou,School of Electrical and Computer Engineering, National Tchnical University of Athens (NTUA), 9 Iroon Polytechniou str.,Athens 15773, Greece Published in IET Renewable Power 2008.
-
Fault Ride-through Requirements for Onshore Wind Power Plants Jens C. Boemer, Arjen A. van der Meer, Barry G. Rawn, Ralph L. Hendriks, Ana R. Ciupuliga,Madeleine Gibescu, Wil L. Kling, Members, IEEE, and Jan A. Ferreira, Fellow, IEEE.
-
Reactive Power Performance Requirements for Wind and Solar Plants A. Ellis, Senior Member, IEEE, R. Nelson, Member, IEEE,
E. Von Engeln, R. Walling, Fellow, IEEE, J.MacDowell, Member, IEEE, L. Casey, Member, IEEE, E. Seymour, Senior Member, IEEE,
W. Peter,Member, IEEE, C. Barker, Member, IEEE, B. Kirby, Senior Member, IEEE, J. R. Williams, Member, IEEE.
-
Low Voltage Ride Through (LVRT) Ability of DFIG based Wind Energy Conversion System II Rishabh Dev Shukla, Student Member, IEEE, Prof. Ramesh Kumar Tripathi, Member, IEEE.
-
A Direct Drive Grid Connected Wind Energy System with STATCOM and Super-capacitor Energy Storage M. Chowdhury, Student Member, IEEE, M. E. Haque, Senior Member, IEEE, A. Gargoom,Member, IEEE, and M. Negnevitsky, Senior Member, IEEE.
-
Application of STATCOM to improve the LVRT of DFIG during RSC Fire-through Fault A. F. Abdou , Student Member IEEE, A. Abu-Siada, Senior Member IEEE and H. R. Pota, Member IEEE.
-
Application of UPFC to Improve the Low-Voltage-Ride-Through Capability of DFIG Yasser M. Alharbi, Student Member, IEEE, A. Abu-Siada, Senior Member IEEE.
-
Modeling, Simulation of UPFC and Its Effect on Power System Protection Pankaj Khandelwal Bharat Modi M.Tech Scholar,,
S.K.I.T. Reader, Electrical Egineering, S.K.I.T. Jaipur, Rajasthan, India Jaipur, Rajasthan, India International Journal of Emerging Research in Management &Technology ISSN: 2278-9359 (Volume- 4, Issue-5).
-
Early Assessment of Grid Code Requirements for Wind Power Plant in Vestas Y. Q. Zhan*, P. Zhao Vestas Technology R&D, 1 Fusionopolis way, Singapore Vestas Technology R&D, 1 Fusionopolis Way, Singapore No. L-1/18/2010-CERC New Delhi, 28th April 2010.
-
A proposed voltage ride through compensators for improving power system performance Hamed H. H. Aly1, Mahdi M. El- Arini2, M. T. Youssef Department of Electrical and Computer Engineering, Dalhousie University, Halifax, NS, B3H 4R2, Canada Electrical Power & Machines Engineering Department, Zagazig University, Faculty of Engineering, Zagazig, Egypt International Journal of Energy and Power Engineering 2013; 2 (2) : 29-36 Published online April 2, 2013.
-
Operation And Control Of Wind Power Station Using Facts Devices Controller Chaudhary Sanjay Haribhai,Indrodia Nayna
,International Refereed Journal of Engineering and Science (IRJES) ISSN 2319-183X, (Print) 2319-1821 Volume 1, Issue 2 (October
2012), PP.17-38.
-
Technical requirements for high-penetration wind energy P Gardner, M Tremblay, D Price Garrad Hassan Canada 21, rue dArtois, F-75008 PARIS.
-
Analysis of High Voltage Shunt Capacitor Bank on Reduced Capacity: The Case of RRVPNL Power Grid Om Prakash Mahela Graduate Student Member IEEE & Junior Engineer-I, RRVPNL Jaipur, India Sheesh Ram Ola Director Professional Group Institute Jaipur, India2013 Annual IEEE India Conference (INDICON) 978- 1-4799-2275-8/13/$31.00 ©2013 IEEE.
-
Draft report on Indian Grid Codes by CENTRAL ELECTRICITY REGULATORY COMMISSION NEW DELHI No. L-1/18/2010- CERC New Delhi, 28th April 2010.
-
Power System Stability and Control by Prabha Kundur.
-
FACTS controllers in power transmission and distribution by
K.R. Padiyar.
-
A Guide to MATLAB for Beginners and Experienced Users by Brian R. Hunt, Ronald L.Lipsman, Jonathan M. Rosenberg, with Kevin R. Coombes, John E. Osborn, and Garrett J. Stuck.
-