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Mr. Y.RAJASEKHAR REDDYMr. Y.RAJASEKHAR REDDYM.Tech, Assistant ProfessorM.Tech, Assistant Professor

Under the Esteemed Guidance of

Photo Voltaic Cell as Power Photo Voltaic Cell as Power Quality conditioner For Grid Quality conditioner For Grid

connected systemconnected system

ByByA.A.Hari PrasadHari Prasad(09c61d5405)(09c61d5405)

OutlinOutlinee

• Introduction

• Power Quality

• Modeling of Case study

• Photovoltaic Cell

• FACTS• MPPT Algorithm

• Power Quality of power Inverters

• Shunt Controllers for Voltage Dip Mitigation

• Simulation Results

• Conclusions

• References

• A computer simulation derived study of photovoltaic cells/ modules, utilizing MATLAB, is demonstrated. This aspect of MATLAB is used to simulate a circuit based model for PV cells/ modules with voltage mitigation solver. In future, the supporting services provided by photovoltaic (PV) systems could speed up their penetration in to power systems. Furthermore, low power PV systems can be used effectively to enhance the power quality using MPPT algorithm. • This project presents a single-phase photovoltaic system that furnishes grid voltage support and compensation of harmonic distortion at the point of common coupling (PCC).

IntroductiIntroductionon

• Any power problem that results in failure or disoperation of customer equipment manifests itself as an economic burden to the user, or produces negative impacts on the environment.

• the power issues which degrade power quality include: Power Factor, Harmonic Distortion, Voltage Transients, Voltage Sags or Dips, Voltage Swells

Power Power QualityQuality

• Power quality can be improved through: Power factor correction, Harmonic filtering, Special line notch filtering, Transient voltage surge suppression, Proper earthing systems.

• The advantages of PQ are Economic Impact, System Losses, Power Service Initial Capital Investments, Equipment Reliability, Power System Adequacy, Environment.

Power Power QualityQuality

• Distributed Power Generating Stations

• In this project, the relation has been adopted to optimize the power extraction from PV panels (MPPT).

Modeling of Case Modeling of Case studystudy

• The solar cell is the elementary building block of the photovoltaic technology. Solar cells are made of semiconductor materials, such as silicon.

Photovoltaic Photovoltaic CellCell

• Types of Electrical Connections– Series Connections– Parallel Connections– Array Connections


Series Connection Parallel Connection


stand-alone photovoltaic system grid-connected photovoltaic system

Photovoltaic Cell – Photovoltaic Cell – System DesignSystem Design

hybrid system incorporating a photovoltaic array and a motor generator set


Photovoltaic Cell - Photovoltaic Cell - InverterInverter

• A Solar inverter or PV inverter is a type of electrical inverter that is made to change the direct current (DC) electricity from a photovoltaic array into alternating current (AC) for use with home appliances and possibly a utility grid

• Types: Stand-alone inverters, Grid tie inverters, Battery backup inverters

• Normally, grid-tied inverters will shut off if they do not detect the presence of the utility grid. If, however, there are load circuits in the electrical system that happen to resonate at the frequency of the utility grid, the inverter may be fooled into thinking that the grid is still active even after it had been shut down. This is called islanding.

• Islanding refers to the condition of a distributed generation (DG) generator continuing to power a location even though power from the electric utility is no longer present.

Photovoltaic Cell - Photovoltaic Cell - anti-anti-

islanding protectionislanding protection

• An inverter designed for grid-tie operation will have anti-islanding protection built in; it will inject small pulses that are slightly out of phase with the AC electrical system in order to cancel any stray resonances that may be present when the grid shuts down.

• Islanding may be detected passively, actively or by utility notification.

Photovoltaic Cell - Photovoltaic Cell - anti-anti-

islanding protectionislanding protection

applications of FACTS-devices are:– Power flow control,– Increase of transmission capability,– Voltage control,– Reactive power compensation,– Stability improvement,– Power quality improvement,– Power conditioning,– Flicker mitigation,– Interconnection of renewable and distributed generation and

storages.

FACTSFACTS

Conventional Vs Facts Devices

FACTSFACTS

• The most used FACTS-device is the SVC or the version with Voltage Source Converter called STATCOM.

• Shunt Devices: These shunt devices are operating as reactive power compensators.

• Series Devices: Series devices have been further developed from fixed or mechanically switched compensations to the Thyristor Controlled Series Compensation (TCSC) or even Voltage Source Converter based devices.

FACTS - DevicesFACTS - Devices

Types of SVC

FACTS - SVCFACTS - SVC

FACTS- D- FACTS- D- StatcomStatcom

STATCOM structure and voltage / current characteristic

6 Pulses STATCOM

principle setup of a TCSC (Series Device)

FACTS - FACTS - TCSCTCSC

Principle configuration of DFC

FACTS - FACTS - DFCDFC

Principle configuration of an UPFC

FACTS - FACTS - UPFCUPFC

FACTS - FACTS - UPFCUPFC

Basic UPFC functional scheme

• MPPT, is an electronic system that operates the Photovoltaic (PV) modules in a manner that allows the modules to produce all the power they are capable of.

• The problem considered by MPPT methods is to automatically find the voltage VMPP or current IMPP at which a PV array delivers maximum power under a given temperature and irradiance.

MPPT AlgorithmMPPT Algorithm

MPPT Algorithm - MPPT Algorithm - TypesTypes

• Fractional Open-Circuit Voltage• Fractional Short-Circuit Current• Perturb and Observe• Incremental Conductance

• Line Commutated Inverters: used for high power converters.

• self-commutated converters: used for small PV-inverters.

• Different inverter concepts are– Single-stage concept of H-bridge PWM DC-DC converter coupled to

the grid with a low frequency (LF) isolation transformer– Multi-stage concept of PWM DC-DC converter front-end including a

high-frequency (HF) isolation transformer, and a 50Hz unfolding bridge coupled to the grid.

Power Quality of power Power Quality of power InvertersInverters

Single-stage concept Multi-stage concept

Power Quality of power Power Quality of power InvertersInverters

Shunt Controllers for Voltage Shunt Controllers for Voltage Dip MitigationDip Mitigation

• Shunt devices are usually adopted to compensate small voltage variations that can be controlled by reactive power injection.

• The shunt controller can be current or voltage controlled

• current controlled: grid-feeding component [Fig (a)]

• voltage controlled : grid-supporting component [Fig (b)]


Vector diagram of the shunt controller providing only reactive power. (a) Current-controlled converter in normal conditions. (b) Voltage-controlled converter in normal condition. (c) Vector diagram for compensation of a voltage dip of 0.15 pu.


Vector diagram of the shunt controller providing both active and reactive powers. (a) Normal conditions. (b) Vector diagram for compensation of a voltage dip of 0.15 pu


Grid-connected PV system with shunt controller functionality


MPPT Algorithm

Matlab ModellingMatlab Modelling

Performance of the voltage-controlled shunt converter with MPPT algorithm: grid voltage E and load voltage Vload

Simulation ResultsSimulation Results

Performance of the voltage-controlled shunt converter with MPPT algorithm: grid current Ig, converter current IC, and load current Iload.


Active and reactive power provided by the shunt-connected multifunctional converter to compensate the voltage sag of 0.15 pu.


Power–voltage characteristic of the PV array and current and voltage on the PV side in the presence

of a grid voltage sag of 0.85 pu.


Performance of the voltage-controlled shunt converter with MPPT algorithm: grid voltage E and load voltage Vload


Performance of the voltage-controlled shunt converter with MPPT algorithm: grid current Ig, converter current , and load current Iload.


Active and reactive power provided by the shunt-connected multifunctional converter to compensate the voltage sag of 0.15 Pu.


• In this project, a single-phase PV system with shunt controller functionality has been presented. The PV converter is voltage controlled with a repetitive algorithm. An MPPT algorithm has specifically been designed for the proposed voltage-controlled converter. It is based on the incremental conductance method, and it has been modified to change the phase displacement between the grid voltage and the converter voltage maximizing the power extraction from the PV panels.

ConclusionsConclusions

[1] F. Blaabjerg, R. Teodorescu, M. Liserre, and A. V. Timbus, “Overview of control and grid synchronization for distributed power generation systems,” IEEE Trans. Ind. Electron., vol. 53, no. 5, pp. 1398–1409, Oct. 2006.

[2] F. Blaabjerg, R. Teodorescu, Z. Chen, and M. Liserre, “Power converters and control of renewable energy systems,” in Proc. ICPE, Pusan, Korea, Oct. 2004.

[3] T.-F. Wu, H. S. Nien, H.-M. Hsieh, and C.-L. Shen, “PV power injection and active power filtering with amplitude-clamping and amplitude scaling algorithms,” IEEE Trans. Ind. Appl., vol. 43, no. 3, pp. 731–741, May/Jun. 2007.

[4] M. Ciobotaru, R. Teodorescu, and F. Blaabjerg, “On-line grid impedance estimation based on harmonic injection for grid-connected PV inverter,” in Proc. IEEE Int. Symp. Ind. Electron., Jun. 4–7, 2007, pp. 2437–2442.

[5] IEEE Standard for Interconnecting Distributed Resources with Electric Power Systems, IEEE Std. 1547-2003, 2003.

ReferencReferenceses

QuerieQueriess

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