A STATCOM-Control Scheme for Grid Connected Wind Energy System for Power Quality Improvement

ABSTRACT:

Injection of the wind power into an electric grid affects the power quality. The performance of the wind turbine and thereby power quality are determined on the basis of measurements and the norms followed according to the guideline specified in International Electro-technical Commission standard, IEC-61400. The influence of the wind turbine in the grid system concerning the power quality measurements are-the active power, reactive power, variation of voltage, flicker, harmonics, and electrical behavior of switching operation and these are measured according to national/international guidelines. The paper study demonstrates the power quality problem due to installation of wind turbine with the grid. In this proposed scheme STATic COMpensator (STATCOM) is connected at a point of common coupling with a battery energy storage system (BESS) to mitigate the power quality issues.

The battery energy storage is integrated to sustain the real power source under fluctuating wind power. The STATCOM control scheme for the grid connected wind energy generation system for power quality improvement is simulated using MATLAB/SIMULINK in power system block set. The effectiveness of the proposed scheme relives the main supply source from the reactive power demand of the load and the induction generator. The development of the grid co-ordination rule and the scheme for improvement in power quality norms as per IEC-standard on the grid has been presented.

 

KEYWORDS:

  1. International electro-technical commission (IEC)
  2. power quality
  3. wind generating system (WGS)

 

SOFTWARE: MATLAB/SIMULINK

 

BLOCK DIAGRAM:

  statcom

Fig.1.System operational scheme in grid system.

 

EXPECTED SIMULATION RESULTS:

  

Fig. 1. Three phase injected inverter Current.

Fig. 2. (a) Source Current. (b) Load Current. (c) Inverter Injected Current. (d) Wind generator (Induction generator) current.


Fig. 3. (a) DC link voltage. (b) Current through Capacitor, 
STATCOM output voltage.

Fig. 5. Supply Voltage and Current at PCC.


Fig.6.(a) Source Current. (b) FFT of source current.                

Fig.7.(a) Source Current. (b) FFT of source current

 

CONCLUSION:

The paper presents the STATCOM-based control scheme for power quality improvement in grid connected wind generating system and with non linear load. The power quality issues and its consequences on the consumer and electric utility are presented. The operation of the control system developed for the STATCOM-BESS in MATLAB/SIMULINK for maintaining the power quality is simulated. It has a capability to cancel out the harmonic parts of the load current. It maintains the source voltage and current in-phase and support the reactive power demand for the wind generator and load at PCC in the grid system, thus it gives an opportunity to enhance the utilization factor of transmission line. The integrated wind generation and STATCOM with BESS have shown the outstanding performance. Thus the proposed scheme in the grid connected system fulfills the power quality norms as per the IEC standard 61400-21.

 

REFERENCES:

 Sannino, “Global power systems for sustainable development,” in IEEE General Meeting, Denver, CO, Jun. 2004.

  • S. Hook, Y. Liu, and S. Atcitty, “Mitigation of the wind generation integration related power quality issues by energy storage,” EPQU J., vol. XII, no. 2, 2006.
  • Billinton and Y. Gao, “Energy conversion system models for adequacy assessment of generating systems incorporating wind energy,” IEEE Trans. on E. Conv., vol. 23, no. 1, pp. 163–169, 2008, Multistate.
  • Wind Turbine Generating System—Part 21, International standard-IEC 61400-21,
  • Manel, “Power electronic system for grid integration of renewable energy source: A survey,” IEEE Trans. Ind. Electron., vol. 53, no. 4, pp. 1002–1014, 2006, Carrasco.

Improving the Dynamic Performance of Wind Farms with STATCOM

ABSTRACT:

When integrated to the power system, large wind farms can pose voltage control issues among other problems. A thorough study is needed to identify the potential problems and to develop measures to mitigate them. Although integration of high levels of wind power into an existing transmission system does not require a major redesign, it necessitates additional control and compensating equipment to enable (fast) recovery from severe system disturbances. The use of a Static Synchronous Compensator (STATCOM) near a wind farm is investigated for the purpose of stabilizing the grid voltage after grid-side disturbance such as a three phase short circuit fault. The strategy focuses on a fundamental grid operational requirement to maintain proper voltages at the point of common coupling by regulating the voltage. The DC voltage at individual wind turbine (WT) inverters is also stabilized to facilitate continuous operation of wind turbines  during disturbances.

 

KEYWORDS:

  1. Wind turbine
  2. Doubly-fed Induction Generator
  3. STATCOM
  4. Three phase fault
  5. Reactive power

 

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

wind farm with statcom

Fig. 1. Block diagram of a Doubly-fed induction generator

Fig. 2 Test System

EXPECTED SIMULATION RESULTS: 

Fig. 3. Voltage at the fault bus (Load bus) , Voltage at the fault bus (Zoomed version)

Fig. 4. Reactive power in the system with no compensating device, Reactive power in the system with mechanically switched capacitors

Fig. 5. Reactive and active power of the 25 MVA STATCOM for Case 3, AC and DC busbar voltages of the STATCOM for Case III.

Fig. 6. Reactive and active powers of only the STATCOM for Case 4, Reactive power and terminal voltage of only the the MSC for Case 4.

Fig. 7. Reactive powers of the system with a STATCOM and MSC

Fig. 8. Reactive power of the 125 MVA STATCOM for Case 5.

 

CONCLUSION:

Wind turbines have to be able to ride through a fault without disconnecting from the grid. When a wind farm is connected to a weak power grid, it is necessary to provide efficient power control during normal operating conditions and enhanced support during and after faults. This paper explored the possibility of connecting a STATCOM to the wind power system in order to provide efficient control. An appropriately sized STATCOM can provide the necessary reactive power compensation when connected to a weak grid. Also, a higher rating STATCOM can be used for efficient voltage control and improved reliability in grid connected wind farm but economics limit its rating. Simulation studies have shown that the additional voltage/var support provided by an external device such as a STATCOM can significantly improve the wind turbine’s fault recovery by more quickly restoring voltage characteristics. The extent to which a STATCOM can provide support depends on its rating. The higher the rating, the more support provided. The interconnection of wind farms to weak grids also influences the safety of wind turbine generators. Some of the challenges faced by wind turbines connected to weak grids are an increased number and frequency of faults, grid abnormalities, and voltage and frequency fluctuations that can trip relays and cause generator heating.

 

REFERENCES:

  • http://www.awea.org/newsroom/releases/Wind_Power_Capacity_012307. html, accessed Nov. 2007.
  • Sun, Z. Chen, F. Blaabjerg, “Voltage recovery of grid-connected wind turbines with DFIG after a short-circuit fault,” 2004 IEEE 35th Annual Power Electronics Specialists Conf., vol. 3, pp. 1991-97, 20-25 June 2004.
  • Muljadi, C.P. Butterfield, “Wind Farm Power System Model Development,” World Renewable Energy Congress VIII, Colorado, Aug- Sept 2004.
  • M. Muyeen, M.A. Mannan, M.H. Ali, R. Takahashi, T. Murata, J. Tamura, “Stabilization of Grid Connected Wind Generator by STATCOM,” IEEE Power Electronics and Drives Systems Conf., Vol. 2, 28-01 Nov. 2005.
  • Saad-Saoud, M.L. Lisboa, J.B. Ekanayake, N. Jenkins, G. Strbac, “Application of STATCOMs to wind farms,” IEE Proceedings – Generation, Transmission, Distribution, vol. 145, pp.1584-89, Sept 1998.

final year eee in ieee electrical projects in mancherial

final year eee in ieee electrical projects in mancherial. 
Software Used: Matlab/Simulink
Areas : Power Electronics and Drives, Power Systems, Renewable Energy and sources, etc
Download
Contact us:
email: asokatechnologies@gmail.com
website: www.asokatechnologies.in
Asoka technologies provide Academic Electrical Projects mancherial.
ELECTRICAL ENGINEERING is a field of engineering that generally deals with the study and application of electricity, electronics, and electro magnetism. This field first became an identifiable occupation in the later half of the 19th century after commercialization of the electric telegraph, the telephone, and electric power distribution and use. Subsequently, broad casting and recording media made electronics part of daily life. The invention of the transistor, and later the integrated circuit, brought down the cost of electronics to the point they can be used in almost any household object.
Electrical engineering has now subdivided into a wide range of sub fields including electronics, digital computers, power engineering, tele communications, control systems, radio-frequency engineering, signal processing, instrumentation, and microelectronics. Many of these sub disciplines overlap and also overlap with other engineering branches, spanning a huge number of specializations such as hardware engineering, power electronics, electro magnetics & waves, microwave engineering, nanotechnology, electro chemistry, renewable energies, mechatronics, electrical materials science, and many more.

Power Quality Improvement of PMSG Based DG Set Feeding Three-Phase Loads

IEEE Transactions on Industry Applications, 2015

ABSTRACT: This paper presents power quality improvement of PMSG (Permanent Magnet Synchronous Generator) based DG (Diesel Generator) set feeding three-phase loads using STATCOM (Static Compensator). A 3-leg VSC (Voltage Source Converter) with a capacitor on the DC link is used as STATCOM. The reference source currents for the system are estimated using an Adaline based control algorithm. A PWM (Pulse Width Modulation) current controller is using for generation of gating pulses of IGBTs (Insulated Gate Bipolar Transistors) of three leg VSC of the STATCOM. The STATCOM is able to provide voltage control, harmonics elimination, power factor improvement, load balancing and load compensation. The performance of the system is experimentally tested on various types of loads under steady state and dynamic conditions. A 3-phase induction motor with variable frequency drive is used as a prototype of diesel engine with the speed regulation. Therefore, the DG set is run at constant speed so that the frequency of supply remains constant irrespective of loading condition.

KEYWORDS:

  1. STATCOM
  2. VSC
  3. IGBTs
  4. PMSG
  5. PWM
  6. DG Set
  7. Power Quality

SOFTWARE: MATLAB/SIMULINK

CIRCUIT DIAGRAM:

Fig. 1 Configuration of PMSG based DG set feeding three phase loads.

EXPECTED SIMULATION RESULTS:

 

Fig. 2. Dynamic performance at linear loads (a) vsab, isa,isb and isc ,(b) vsab, iLa,iLb and iLc (c) Vdc, isa,iLa and iCa

CONCLUSION:

The STATCOM has improved the power quality of the PMSG based DG set in terms voltage control, harmonics elimination and load balancing. Under linear loads, there has been negligible voltage variation (From 219.1 V to 220.9 V) and in case of nonlinear load, the voltage increases to 221 V. Thus, the STATCOM has been found capable to maintain the terminal voltage of DG set within ± 0.5% (220 ±1 V) under different linear and nonlinear loads.

Under nonlinear loads, the load current of DG set is a quasi square with a THD of 24.4 %. The STATCOM has been found capable to eliminate these harmonics and thus the THD of source currents has been limited to 3.9 % and the THD of terminal voltage has been observed of the order of 1.8%. Therefore, the THDs of source voltage and currents have been maintained well within limits of IEEE-519 standard under nonlinear load.

It has also been found that the STATCOM maintains balanced source currents when the load is highly unbalanced due to removal of load from phase ‘c’. The load balancing has  also been achieved by proposed system with reduced stress on the winding of the generator.

The proposed system is a constant speed DG set so there is no provision of frequency control in the control algorithm.

However, the speed control mechanism of prototype of the diesel engine is able to maintain the frequency of the supply almost at 50 Hz with small variation of ±0.2 %.

Therefore, the proposed PMSG based DG set along with STATCOM can be used for feeding linear and nonlinear balanced and unbalanced loads. The proposed PMSG based DG set has also inherent advantages of low maintenance, high efficiency and rugged construction over a conventional wound field synchronous generator based DG set.

 REFERENCES:

[1] Xibo Yuan; Fei Wang; Boroyevich, D.; Yongdong Li; Burgos, R., “DC-link Voltage Control of a Full Power Converter for Wind Generator Operating in Weak-Grid Systems,” IEEE Transactions on Power Electronics, vol.24, no.9, pp.2178-2192, Sept. 2009.

[2] Li Shuhui, T.A. Haskew, R. P. Swatloski and W. Gathings, “Optimal and Direct-Current Vector Control of Direct-Driven PMSG Wind Turbines,” IEEE Trans. Power Electronics, vol.27, no.5, pp.2325-2337, May 2012.

[3] M. Singh and A. Chandra, “Application of Adaptive Network-Based Fuzzy Inference System for Sensorless Control of PMSG-Based Wind Turbine With Nonlinear-Load-Compensation Capabilities,” IEEE Trans. Power Electronics, vol.26, no.1, pp.165-175, Jan. 2011.

[4] A. Rajaei, M. Mohamadian and A. Yazdian Varjani, “Vienna-Rectifier-Based Direct Torque Control of PMSG for Wind Energy Application,” IEEE Trans. Industrial Elect., vol.60, no.7, pp.2919-2929, July 2013.

[5] Mihai Comanescu, A. Keyhani and Dai Min, “Design and analysis of 42-V permanent-magnet generator for automotive applications,” IEEE Trans. Energy Conversion, vol.18, no.1, pp.107-112, Mar 2003.

Performance comparison of PI & ANN based STATCOM for 132 KV transmission line  

International Conference on Electrical, Electronics, and Optimization Techniques (ICEEOT) – 2016

ABSTRACT: This paper presents simulation model of the 132KV transmission line with comparison of ANN based STATCOM and conventional PI based STATCOM. The STATCOM being the state-of-the-art VSC based dynamic shunt compensator in FACTS family is used now a days in transmission system for reactive power control, increase of power transfer capacity, voltage regulation etc. Such type of controller is applied at the middle of the transmission line to enhance the power transmission capacity of the line. The simulation result shows that the STATCOM is effective improve the power factor and voltage regulation for the 132kV line loading.

 KEYWORDS:

  1. STATCOM
  2. PI
  3. ANN control strategy
  4. MatLab simulink

 SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

 Fig 1: Schematic Representation of the Control Circuit.

 EXPECTED SIMULATION RESULTS:

 

Fig 2 1-phase current and voltage waveform using STATCOM

Fig3 Phase Current and Voltage waveform when the STATCOM is ON

Fig 4Phase Current and Voltage waveform when Load is Varied in the system

Fig 5 Phase Current and Voltage waveform when suddenly a Load is remove from the system at 0.4sec

Fig 6 3-phase current and voltage waveform using STATCOM

Fig 7 Active and Reactive power flow in Transmission system using STATCOM

Fig8 1-phase current and voltage waveform for STATCOM using ANN

Fig 9 Phase Current and Voltage waveform when the STATCOM is ON

Fig 10 1 Phase Current and Voltage waveform when Load is Varied in the System

Fig11 3-phase voltage and current waveform for STATCOM using ANN

CONCLUSION:

The paper present that the STATCOM bring the power factor to the unity thereby enhancing the power transfer capability by supplying or absorbing controllable amount of reactive power. By using a STATCOM with ANN controller and the Response time is faster comparing to the PI Controller because of this voltage regulation maintained within a limit. More over ANN Controlled STATCOM will improve the stability of the system and improve the dynamic performance of the system.

REFERENCES:

[1] B.Sing ,R.saha, A.Chandra “Static Synchronous Compensator (STATCOM): a review” IET Power Electronic 2008

[2] N.G Hingroni and I Gyugyi. “Understanding FACTS: Concepts and Technology of flexible AC Transmission System”, IEEE Press, New York, 2000.

[3] D.J Hanson, M.L.Woodhouse, C.Horwill “STATCOM: a new era of Reactive Compensation” Power Engineering Journal June 2002

[4] Mustapha Benghanem — Azeddine Draou” A NEW MODELLING AND CONTROL ANALYSIS OF AN ADVANCED STATIC VAR COMPENSATOR USING A THREE–LEVEL (NPC) INVERTER TOPOLOGY” Journal of ELECTRICAL ENGINEERING, VOL. 57, NO. 5, 2006, 285–290

[5] Jagdish Kumar, Biswarup Das, and Pramod Agarwal “ Modeling of 11- Level Cascade Multilevel STATCOM” International Journal of Recent Trends in Engineering, Vol 2, No. 5, November 2009

Comparative Analysis of 6, 12 and 48 Pulse T-STATCOM

2016, IEEE 

ABSTRACT: This paper presents the performance and comparative analysis of Static Synchronous Compensator (STATCOM) based on 6, 12 and 48-pulse VSC configuration. STATCOM is implemented for regulation of the voltage at the Point of Common Coupling (PCC) bus which has time-variable loads. The dq decoupled current control strategy is used for implementation of STATCOM, where modulation index M and phase angle ø are varied for achieving voltage regulation at the PCC bus. The 6, 12 and 48-pulse configurations are compared and analyzed on the basis of Total Harmonic Distortion (THD) and time response parameters such as rise time, maximum overshoot and settling time. The simulation of various configurations of STATCOM is carried out using power system block-set in MATLAB/Simulink platform.

KEYWORDS:

  1. FACTS
  2. STATCOM
  3. Decoupled current control system
  4. Voltage Sourced Converter
  5. Total Harmonic Distortion

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

 

Fig.1:Single line diagram of STATCOM.

 EXPECTED SIMULATION RESULTS:

 

 

Fig. 2: PCC bus voltage-VM for 6, 12 and 48 pulse STATCOM respectively.

Fig. 3: q-axis STATCOM current-ishq for PI controller of 6, 12 and 48 pulse STATCOM respectively.

Fig. 4: d-axis STATCOM current-ishd for PI controller of 6, 12 and 48 pulse STATCOM respectively.

a: Dc capacitor voltage-Vdc

b: Active power of loads-PL

c: Reactive power-Qstat

                                d: Active power-Pstat

Fig. 5: Vdc, PL, Qstat and Pstat for 48 pulse STATCOM respectively.

CONCLUSION:

In this paper, for voltage regulation and dynamic power flow control a 48-pulse ±100 MVA two-level GTO STATCOM has been modeled and simulated using decoupled current control strategy. By varying the modulation index (M) and phase angle (ɸ) between PCC bus voltage and STATCOM voltage, voltage regulation at the PCC bus is achieved. The THD and various time response parameters of 6, 12 and 48 pulse STATCOM are compared. The results show that THD of output voltage of 48 pulse STATCOM is less than 5%, which satisfies the IEEE 519 standard. Hence, there is no need of active filter. Also, 48 pulse STATCOM has better transient response as compared to 6, 12 pulse STATCOM.

REFERENCES:

[1] K. Padiyar, FACTS controllers in power transmission and distribution. New Age International, 2007.

[2] K. K. Sen and M. L. Sen, Introduction to FACTS controllers: theory, modeling, and applications. John Wiley & Sons, 2009, vol. 54.

[3] A. Edris, “Facts technology development: an update,” IEEE Power engineering review, vol. 20, no. 3, pp. 4–9, 2000.

[4] El-Moursi and A.M. Sharaf, “Novel controllers for the 48-pulse vscstatcom and ssscfor voltage regulation and reactive power compensation,” IEEE Transactions on Powersystems, vol. 20, no. 4, pp. 1985–1997, 2005.

[5] N. G. Hingorani and L. Gyugyi, Understanding FACTS: concepts and technology of flexible AC transmission systems. Wiley-IEEE press, 2000.

Modeling of 18-Pulse STATCOM for Power System Applications

ABSTRACT:

 A multi-pulse GTO based voltage source converter (VSC) topology together with a fundamental frequency switching mode of gate control is a mature technology being widely used in static synchronous compensators (STATCOMs). The present practice in utility/industry is to employ a high number of pulses in the STATCOM, preferably a 48-pulse along with matching components of magnetics for dynamic reactive power compensation, voltage regulation, etc. in electrical networks. With an increase in the pulse order, need of power electronic devices and inter-facing magnetic apparatus increases multi-fold to achieve a desired operating performance. In this paper, a competitive topology with a fewer number of devices and reduced magnetics is evolved to develop an 18-pulse, 2-level + 100MVAR STATCOM in which a GTO-VSC device is operated at fundamental frequency switching gate control. The inter-facing magnetics topology is conceptualized in two stages and with this harmonics distortion in the network is minimized to permissible IEEE-519 standard limits. This compensator is modeled, designed and simulated by a Sim Power Systems tool box in MATLAB platform and is tested for voltage regulation and power factor correction in power systems. The operating characteristics corresponding to steady state and dynamic operating conditions show an acceptable performance.

KEYWORDS:

  1. Fast Fourier transformation
  2. Gate-turn off thyristor
  3. Magnetic
  4. STATCOM
  5. Total harmonic distortion
  6. Voltage source converter

SOFTWARE: MATLAB/SIMULINK

MATLAB MODEL:

Fig. 1 MATLAB model of ±100MVAR 18-pulse STATCOM

EXPECTED SIMULATION RESULTS:

Fig. 2 Three phase instantaneous voltage(va , vb, vc) and current (ia, ib, ic) with 75MW 0.85pf lagging load when V* sets at 1.0pu, 1.03pu and 0.97pu

Fig. 3 Operating characteristics in voltage regulation mode for 70MW, 0.85pf(lag) load

Fig. 4 Voltage(va) spectrum in capacitive mode

Fig. 5. Voltage spectrum (va) in inductive mode.

Fig. 6. Current (ia) spectrum in capacitive mode.

Fig. 7. Current spectrum (ia) in inductive mode.

Fig. 8 Operating characteristics for unity power factor (upf) Correction in var control mode for 75MW, 0.85pf(lag) load

Fig. 9. Voltage harmonics(va) spectrum for upf correction.

Fig. 10 Current harmonics(ia) spectrum for upf correction

Fig. 11 Operating characteristics following 10% load injection at the instant of 0.24s in voltage regulation mode on 70MW, 0.85pf(lag) load

Fig. 12 Voltage harmonics (va) spectrum after load variation

Fig. 13. Current harmonics (ia) spectrum after load variation.

Fig. 14 Operating characteristics in var control mode for incremental Load variation of 10% at the instant of 0.24s on an initial load of 70MW, 0.85pf(lag)

Fig. 15 Voltage harmonics (va) spectrum after the load injection

Fig. 16. Current harmonics (ia) spectrum after the load injection.

CONCLUSION:

A new 18-pulse, 2-level GTO-VSC based STATCOM with a rating of + 100MVAR, 132kV was modeled by employing three fundamental 6-pulse VSCs operated at fundamental frequency gate switching in MATLAB platform using a Sim Power Systems tool box. The inter-facing magnetics have evolved in two stage sinter- phase transformers (stage-I) and phase shifter (stage-II), and with this topology together with standard PI-controllers, harmonics distortion in the network has been greatly minimized to permissible IEEE-519 standard operating limits [9]. The compensator was employed for voltage regulation, power factor correction and also tested for dynamic load variation in the network. It was observed from the various operating performance characteristics which emerged from the simulation results that the model satisfies the network requirements both during steady state and dynamic operating conditions. The controller has provided necessary damping to settle rapidly steady states for smooth operation of the system within a couple of cycles. The proposed GTO-VSC based 18-pulse STATCOM seems to provide an optimized model of competitive performance in multi-pulse topology.

REFERENCES:

[1] Colin D. Schauder, “Advanced Static VAR Compensator Control System,” U.S. Patent 5 329 221, Jul. 12, 1994.

[2] Derek A. Paice, “Optimized 18-Pulse Type AC/DC, or DC/AC Converter System,” U.S. Patent 5 124 904, Jun. 23, 1992.

[3] Kenneth Lipman, “Harmonic Reduction for Multi-Bridge Converters,” U.S. Patent 4 975 822, Dec. 4, 1990.

[4] K.K. Sen, “Statcom – Static Synchronous Compensator: Theory, Modeling, And Applications,” IEEE PES WM, 1999,Vol. 2, pp. 1177 –1183.

[5] Guk C. Cho, Gu H. Jung, Nam S. Choi, et al. “Analysis and controller design of static VAR compensator using three-level GTO inverter,” IEEE Transactions Power Electronics, Vol.11, No.1, Jan 1996, pp. 57 –65.

Cascaded Control of Multilevel Converter based STATCOM for Power System Compensation of Load Variation

ABSTRACT:

The static synchronous compensator (STATCOM) is used in power system network for improving the voltage of a particular bus and compensate the reactive power.It can be connected to particular bus as compensating device to improve the voltage profile and reactive power compensation. In this paper, a multi function controller is proposed and discussed. The control concept is based on a linearization of the d-q components with cascaded controller methods. The fundamental parameters are controlled with using of proportional and integral controller. In closed loop method seven level cascaded multilevel converter (CMC) is proposed to ensure the stable operation for damping of power system oscillations and load variation.

KEYWORDS:

  1. FACTS
  2. PWM
  3. CMC
  4. STATCOM

 SOFTWARE: MATLAB/SIMULINK

TEST SYSTEM:

 Figure 1.STATCOM network connection.

 EXPECTED SIMULATION RESULTS:

Figure 2. Load terminal dq0 Currents with Load variation

Figure 3. Source terminal dq0 Currents with Load variation.

Figure 4. Iqref output for load rejection.

Figure 5. Source Voltage for load rejection with AGC.

Figure 6. THD of output Voltage of Cascaded Multilevel converter.

Figure 7. THD of output Current of Cascaded Multilevel Converter

Figure 8.Source Active and Reactive power.

Figure 9. Power factor in Load and Source Bus

Figure 10.Three phase Supply Voltage of multilevel converter.

 CONCLUSION:

The cascaded controller is designed for seven level CMC based STATCOM. This control scheme regulates the capacitor voltage of the STATCOM and maintain rated supply voltage for any load variation with in the rated value. It has been shown that the CMC is able to reduce the THD values of output voltage and current effectively. The CMC based STATCOM ensures that compensate the reactive power and reduce the harmonics in output of STATCOM.

 REFERENCES:

[1] N. Hingorani and L. Gyugyi, 2000, “Understanding FACTS: Concepts and Technology Flexible AC Transmission Systems”, New York: IEEE Press.

[2] P. Lehn and M. Iravani, Oct.1998, “Experimental evaluation of STATCOM closed loop dynamics”, IEEE Trans. Power Delivery, vol.13, pp.1378-1384.

[3] Mahesh K.Mishra and Arindam Ghosh, Jan 2003, ”Operation of a D-STATCOM in Voltage Control Mode”, IEEE Trans. Power Delivery, vol.18, pp.258-264.

[4] Arindam Ghosh, Avinash Joshi, Jan 2000, ”A New Approach to Load Balancing and Power Factor Correction in Power Distribution System”, IEEE Trans. Power Delivery, vol.15, No.1, pp. 417-422.

[5] Arindam Ghosh, Gerard Ledwich, Oct 2003,”Load Compensating DSTATCOM in Weak AC Systems”, IEEE Trans. Power Delivery, vol.18, No.4, pp.1302-1309.

 

A Five Level Cascaded H-Bridge Multilevel STATCOM

2015, IEEE

ABSTRACT: This paper describes a three-phase cascade Static Synchronous Compensator (STATCOM) without transformer. Lt presents a control algorithm that meets the demand of load reactive power and also voltage balancing of isolated dc capacitors for H-bridges. The control algorithm used for inverter in this paper is based on a phase shifted carrier (PSC) modulation strategy that has no restriction on the cascaded number. The performance of the STATCOM for different changes of loads was simulated.

 KEYWORDS:

  1. STATCOM
  2. PSCPWM
  3. Cascaded Multilevel Inverter

 SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

Fig1.cascaded multilevel STATCOM.

EXPECTED SIMULATION RESULTS:

 

Fig. 2 Source voltage, source current and inverter current far inductive load(sourece current gain-5 and Inverter current gain-8).

Fig. 3 Load & Inverter Reactive componenets of current for Inductive load.

F ig. 4 Response of DC link voltage for inductive load.

Fig. 5 Source voltage and inverter current for the change of inductive load to half of the load at I sec(lnverter current gain-8)

Fig. 6 Load & Inverter Reactive componenets of current for the change of Inductive load to half of the load at I sec.

Fig. 7 Source voltage and inverter current for the change of inductive load to standby at 1 sec (Inverter current gain-8).

Fig. 8 Load & Inverter Reactive componenets of current for the change of Inductive load to standby at 1 sec

F ig. 9 Inverter Output Voltage

Fig. 10 Harmonie spectrum ofInverter line voltage.

Fig. 11 Load & Inverter reactive component for the change of Inductive to

capacitive load at 1.5 Sec.

Fig. 12 Response of oe link voltage for change in mode of operation from

inductive to capacitive load at 1.5 Sec.

Fig. 13 Inverter reactive component for the change of Inductive to capacitive load at 2 Sec

Fig. 14 Response of OC link voltage for change in mode of operation from inductive to capacitive at 2 Sec

CONCLUSION:

The cascaded H-bridge multilevel topology is used as one of the more suitable topologies for reactive-power compensation applications. This paper presents a new control strategy for cascaded H-bridge multilevel converter based STATCOM. By this control strategy, the dc-link voltage of the inverter is controlled at their respective values when the ST A TCOM mode is converted from inductive to capacitive. The dc link voltages of the inverter are kept balanced in all the circumstances, and the reactive power that is produced by the STATCOM is equally distributed among all the H-bridges.

REFERENCES:

[1] N. N. V. Surendra Babu, and B.G. Fernandes, ” Cascaded Two Level Inverter- Based Multilevel ST ATCOM for High-Power Applications,” IEEEE Trans. Power Delivery., vol. 29, no. 3, pp. 993-1001, lune. 2014.

[2] N.G. Hingorani and L. Gyagyi, “Understanding F ACTS”, Delhi, India: IEEE, 2001, Standard publishers distributors.

[3] B. Singh, R. Saha, A. Chandra, and K. AI- Haddad, ” Static synchronous compensators (ST A TCOM): A review, ” lET Power Electron., vol. 2, no. 4, pp. 297-324, 2009.

[4] Hirofumi Akagi, Shigenori Inoue and Tsurugi Yoshii, “Control and Performance of a Transformerless Cascade PWM ST A TCOM With Star Contiguration,” IEEE Trans. Ind. Appl., vol. 43, no. 4, pp. 1041-1049, July/ August 2007.

[5] H. Akagi, H. Fujita, S.Yonetaniand Y. Kondo, “A 6.6-kV transformerless ST ATCOM based on a tivelevel diode-clamped PWM converter: System design and experimentation of a 200-V 1 O-kV A laboratory model,” IEEE Trans. Ind. Appl., vol. 44, no. 2, pp. 672-680, Mar./Apr. 2008.

Enhancement of Power Quality in Distribution System using D-Statcom

ABSTRACT:

STATCOM (static synchronous compensator) as a shunt-link flexible AC transmission system(FACTS) controller has shown extensive feasibility in terms of cost-effectiveness in a wide range of problem solving abilities from transmission to distribution levels. Advances in power electronic technologies such as Voltage Source Converter (VSC) improves the reliability and functionality of power electronic based controllers hence resulting in increased applications of STATCOM. In this paper, design and implementation of a Distribution type, Voltage Source Converter (VSC) based static synchronous compensator (DSTATCOM) has been carried out. It presents the enhancement of power quality problems, such as voltage sag and swell using Distribution Static Compensator (D-STATCOM) in distribution system. The model is based on Sinusoidal Pulse Width Modulation (SPWM) technique. The control of the Voltage Source Converter (VSC) is done with the help of SPWM. The main focus of this paper is to compensate voltage sag and swell in a distribution system. To solve this problem custom power devices are used such as Fixed Compensators (FC, FR), Synchronous Condenser, SVC, SSSC, STATCOM etc. Among these devices Distribution STATCOM (DSTATCOM) is the most efficient and effective modern custom power device used in power distribution networks. DSTATCOM injects a current into the system to mitigate the voltage sag and swell. The work had been carried out in MATLAB environment using Simulink and SIM power system tool boxes. The proposed D-STATCOM model is very effective to enhance the power quality of an isolated distribution system feeding power to crucial equipment in remote areas. The simulations were performed and results were found to be satisfactory using MATLAB/SIMULINK.

KEYWORDS:

  1. Statcom
  2. Facts Controllers
  3. D-Statcom
  4. Voltage Source Converter
  5. Total Harmonic Distortions

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

Fig.1 Schematic diagram of D-STATCOM

 EXPECTED SIMULATION RESULTS:

 

 Fig.2 Three Phase to Ground -Voltage at Load Point is 0.6600 p.u

Fig.3 Double Line to Ground- Voltage at Load Point is 0.7070 p.u

Fig.4 Line to Line- Voltage at Load Point is 0.7585

Fig.5 Single Line to Ground- Voltage at Load Point is 0.8257

Fig.6 The waveforms shows THD (41.31%) results of fixed load and variable inductive load.

Fig..7 The wave forms shows THD (21.28%) results of fixed load and variable capacitive load

Fig.8 Three Phase to Ground-Voltage at Load Point is 0.9367 p.u

Fig.9 Double Line to Ground- Voltage at Load Point is0.9800 p.u

Fig.10 Line to Line- Voltage at Load Point is 1.068

Fig.11 Single Line to Ground – Voltage at Load Point is 0.9837

Fig.12 The waveform for pure inductive,capacitive loads with statcom

Fig.13 The waveform for without filter THD results 41.31%

Fig.14 The above waveform for with filter THD results 1.11%

 CONCLUSION:

The simulation results show that the voltage sags can be mitigate by inserting D-STATCOM to the distribution system. By adding LCL Passive filter to D-STATCOM, the THD reduced. The power factors also increase close to unity. Thus, it can be concluded that by adding DSTATCOM with LCL filter the power quality is improved.

REFERENCES:

[1] A.E. Hammad, Comparing the Voltage source capability of Present and future Var Compensation Techniques in Transmission System, IEEE Trans, on Power Delivery. Volume 1. No.1 Jan 1995.

[2] G.Yalienkaya, M.H.J Bollen, P.A. Crossley, “Characterization of Voltage Sags in Industrial Distribution System”, IEEE transactions on industry applications, volume 34, No. 4, July/August, PP.682-688, 1999

[3] Haque, M.H., “Compensation of Distribution Systems Voltage sags by DVR and D STATCOM”, Power Tech Proceedings, 2001 IEEE Porto, Volume 1, PP.10-13, September 2001.

[4] Anaya-Lara O, Acha E., “Modeling and Analysis Of Custom Power Systems by PSCAD/EMTDC”, IEEE Transactions on Power Delivery, Volume 17, Issue: 2002, Pages: 266 272.

[5] Bollen, M.H.J.,”Voltage sags in Three Phase Systems”, Power Engineering Review, IEEE, Volume 21, Issue: 9, September 2001, PP: 11-