Matlab Simulations Using D-STATCOM and UPQC in Solar Photovoltaics. A Power Quality Analysis


Textbook, 2019
60 Pages

Excerpt

Table of Contents

Title Page

About the Author

Preface

List of Tables

List of Figures

List of Abbreviations

Table of contents 07-

Chapter 1 Introduction 10
1.1 Introduction
1.2 Overview of Renewable Energy
1.3 Relevance of Renewable Energy in India
1.3.1 Grid-interactive renewable power
1.3.2 Off-Grid Renewable Power
1.4 Chapter Conclusion

Chapter 2 Introduction to Custom Power Devices 15
2.1 Introduction
2.2 Introduction to D-STATCOM
2.3 Introduction to Unified Power Quality Conditioner (UPQC)
2.4 Basic configuration of UPQC
2.4.1 Series converter
2.4.2 Shunt converter
2.4.3 Midpoint-to-ground DC capacitor bank
2.4.4 Low-pass filter
2.4.5 High-pass filter
2.4.6 Series and Shunt transformers
2.5 Functions performed by UPQC

Chapter 3 Fault Analysis of Power Conditioning Systems
3.1 Introduction
3.2 Controlling Approach in Simulation Model
3.3 Simulation Results and Discussion
3.4 Chapter Conclusion

Chapter 4 Impact of D-STATCOM on Power Quality Aspects
4.1 Introduction
4.2 Control Methodology using D-STATCOM
4.3 Simulation Results and Discussion
4.4 Chapter Conclusion

Chapter 5 Effect of Three Phase Fault on PV System
5.1 Introduction
5.2 Computational Block Diagram
5.3 Voltage and Current Controllers
5.4 Maximum Power Point Tracking
5.5 Results and Discussion
5.6 Chapter Conclusion

Chapter 6 Impact of UPQC on Solar PV Grid Connected Systems
6.1 Introduction
6.2 Operation of UPQC
6.3 Results and Discussion
6.4 Chapter Conclusion

Chapter 7 Future Scope of Work

List of References

About the Author

Akhil Gupta received B.E in Electrical Engineering from Giani Zail Singh College of Engineering & Technology, Bathinda in 1999 and M. Tech in Electrical Power Systems from Kay Jay group of Institutes, Patiala in 2005. He obtained his Ph.D. from Department of Electrical Engineering at National Institute of Technology Kurukshetra Haryana in 2016. He has around 19 years in total of academic and industrial experience and has worked at all academic positions in engineering with reputed technical institutes of North India affiliated with government organizations. Presently he is working as Assistant Professor in I.K. Gujral Punjab Technical University Batala campus (a constituent campus of I.K. Gujral Punjab Technical University Jalandhar, Kapurthala), Punjab, India. He has published more than 30 research papers in various peer reviewed and indexed National/International journals and conference proceedings. He has attended and conducted around 30 faculty and student workshops. His areas of research are: power quality, smart grids, and application of solar photovoltaic systems into electrical power systems.

PREFACE

India’s plan to ramp up solar power generation to 100 GW by 2022 is among the largest in the world. It aims to bring sustainable, clean, climate-friendly electricity to millions of India’s people. The World Bank Group is moving to help India deliver on its unprecedented plans to scale up solar energy from installing solar panels on rooftops to setting up massive solar parks. This will catapult India to the forefront of the global effort to bring electricity to all, mitigate the effects of climate change, and set the country on a path to become the 'India of the future'. Solar power in Indiais a fast developing industry, with a cumulative installed grid connected solar power capacity of 26,025.97 MW (26 GW) as of 31st December 2019.The Indian government has significantly expanded its solar plans, targetingUS$100 billion of investmentand 100 GW of solar capacity(including 40 GW from rooftop solar) by 2022.

This book presents the status of renewable energy and solar PV technology at the beginning. A solar Photovoltaic (PV) cell converts solar radiation into electric energy with the help of a diode, two resistances and connected load. In order to harness the maximum power, Maximum Power Point Tracking (MPPT) technique is used which is able to generate the power at Maximum Power point (MPP). The importance of two custom power devices namely, Distributed Static Compensator (D-STATCOM) and Unified Power Quality Conditioner (UPQC) is highlighted with its impact on Power Quality (PQ) especially considering various PQ issues.

In this book, the impact of three-phase fault at unity power on the performance of solar PV grid tied system is highlighted. The PQ system performance has been evaluated under the influence of three-phase fault and waveforms are studied. The effect of fault has been discussed at Point of Common Coupling (PCC) and Total Harmonic Distortion (THD) analysis has been done using the Fast Fourier Transform (FFT) tool of Matlab software. Finally, the THD at the various points of PCC are calculated and discussed at fundamental frequency.

Finally, the role of D-STATCOM and UPQC in improving the PQ aspects for a solar PV grid tied system at unity power factor. Sag has been reduced in the current waveforms obtained at PCC whereas the THD levels have been reduced for utility grid side (i.e. the point where the fault has been introduced). In this way, it can be concluded that D-STATCOM and UPQC have been able to improve the PQ aspects mainly sag, swells and harmonic levels at fundamental frequency.

List of Tables

Page No.

Table 1.1: Plan wise capacity addition in grid connected renewable capacity [3] 13

Table 1.2: Off-Grid / Captive Renewable Power [3] 14

Table 3.1: Parameters of PV grid connected system 21

Table 3.2: Specifications adopted for single PV array (Kyocera KD135GX-LP) [8] 21

Table 3.3: Total harmonic distortion analysis without D-STATCOM 27

Table 4.1: Total harmonic distortion analysis 35

Table 5.1: Specifications adopted for single PV array (BP Solar SX3190) [9] 39

Table 5.2: Parameters of a VSC main controller 39

List of Figures

Figure 2.1 Configuration of a D-STATCOM 16

Figure 2.2 Basic Configuration of UPQC [4] 17

Figure 3.1 Simulation model of solar PV grid tied system with connected load 20

Figure 3.2. Without D-STATCOM Simulink waveforms for (a) Three-phase converter current (b) Three-phase converter voltage (c) Three-phase load current (d) Three-phase load voltage (e) Three-phase grid current (f) Three-phase grid voltage 22-25

Figure 3.3. Without D-STATCOM (a) Duty cycle of DC-DC boost converter (b) Comparison of DC link voltage with MPPT voltage 25-26

Figure 3.4 Without D-STATCOM, analysis of (a) Active power (b) Reactive power 26-27

Figure 4.1: Implementation of D-STATCOM into solar PV grid tied system 29

Figure 4.2. With D-STATCOM Simulink waveforms for (a) Three-phase converter current

(b) Three-phase converter voltage (c) Three-phase load current (d) Three-phase load voltage (e) Three-phase grid current (f) Three-phase grid voltage 30-33

Figure 4.3. Without D-STATCOM, analysis of (a) Comparison of DC link voltage with MPPT voltage (b) Active power (c) Reactive power 33-34

Figure 5.1. Block diagram of double stage grid connected solar PV system 37

Figure 5.2. Simulink diagram of DC voltage PI controller 37

Figure 5.3. Simulink diagram of DC current PI controller 38

Figure 5.4. Measurement of current, voltage and power in MATLAB simulation 38

Figure 5.5. Flowchart of Perturb & Observe MPPT technique 40

Figure 5.6. Impact of fault on three-phase (a) grid current (b) load current and

(c) converter current 42

Figure 5.7. Impact of fault on three-phase (a)-(c) real power (d)-(f) reactive power, of solar array, load and utility grid 43-44

Figure 5.8. Impact of fault on three-phase (a) converter voltage (b) load voltage and

(c) grid voltage 45

Figure 5.9. Impact of fault on (a) DC link voltage (b) modulation index 46-47

Figure 6.1. Synchronization operation of UPQC with solar PV grid tied system 49

Figure 6.2. (a) Three-phase voltage output of shunt controller

(b) Three-phase current output of shunt controller 50

Figure 6.3. Impact of UPQC on three-phase (a) grid current (b) load current and

(c) converter current, in the presence of three-phase fault 51-52

Figure 6.4. Impact of UPQC on three-phase (a)-(c) real power (d)-(f) reactive power, of solar array, load and utility grid 52-53

Figure 6.5. Impact of UPQC on three-phase (a) converter voltage (b) load voltage and

(c) grid voltage, in the presence of three-phase fault 54-55

Figure 6.6. Impact of UPQC on (a) DC link voltage (b) modulation index, in the presence of three-phase fault 55-56

List of Abbreviations

Custom Power Devices (CPD)

Distributed Static Compensator (D-STATCOM)

Fast Fourier Transform (FFT)

Flexible AC Transmission System (FACTS)

Incremental Conductance (IC)

Insulated Gate Bipolar Junction Transistors (IGBTs)

Insulated Gate Bipolar transistor (IGBT)

Maximum Power Point (MPP)

Maximum Power point Tracking (MPPT)

Photovoltaic (PV)

Perturbation & Observation (P&O)

Phase Locked Loop (PLL)

Point of Common Coupling (PCC)

Power Quality (PQ)

Power-Voltage (P-V) and Current-Voltage (I-V)

Proportional Integral (PI)

Pulse Width Modulation (PWM)

Resistance Inductance (RL)

Total Harmonic Distortion (THD)

Voltage Source Converter (VSC)

Unified Power Quality Conditioner (UPQC)

Chapter 1

INTRODUCTION

1.1 Introduction

The Kyoto agreement on global reduction of greenhouse gas emissions has prompted renewed interest in renewable energy systems worldwide. Many renewable energy technologies today are well developed, reliable, and cost competitive with the conventional fuel generators. The cost of renewable energy technologies is on a falling trend and is expected to fall further as demand and production increases. There are many renewable energy sources such as biomass, solar, wind, mini-hydro, and tidal power. However, solar energy systems make use of advanced power electronics technologies and, therefore the focus will be on solar Photovoltaic (PV) in this work. One of the advantages offered by renewable energy sources is their potential to provide sustainable electricity in areas not served by the conventional power grid. The growing market for renewable energy technologies has resulted in a rapid growth in the need for power electronics. Most of the renewable energy technologies produce DC power, and hence power electronics and control equipment are required to convert the DC into AC power. Inverters are used to convert DC to AC. There are two types of inverters: stand-alone and grid-connected. The two types have several similarities, but are different in terms of control functions. A stand-alone inverter is used in off-grid applications with battery storage. With backup diesel generators (such as PV-diesel hybrid power systems), the inverters may have additional control functions such as operating in parallel with diesel generators and bidirectional operation (battery charging and inverting). Grid-interactive inverters must follow the voltage and frequency characteristics of the utility-generated power presented on the distribution line. For both types of inverters, the conversion efficiency is a very important consideration.

Power electronics and power quality are irrevocably linked together. With the dramatic increase over the last 20 years in energy conversion systems utilizing power electronic devices, there is the emergence of Power Quality (PQ) as a major field of power engineering. Power electronic technology has played a major role in creating PQ and simple control algorithm modifications. This technology can play a dominant role in enhancing overall quality of electrical energy available to end-users. While many studies suggest increase in power electronic based energy utilization as high as 70-80% (of all energy consumed), it is equally clear that there is the beginning to realize the total benefit of such end-use technologies. PQ problems associated with grounding, sags, harmonics, and transients [1] continues to increase because of the sheer number of sensitive electronic loads expected to be placed in service. To utility suppliers, PQ initially referred to the quality of the service delivered as measured by the consumer’s ability to use the energy delivered in the desired manner. This conceptual definition included such conventional utility planning topics as voltage and frequency regulation and reliability. The end-user’s definition of PQ also centers around their ability to use the delivered energy in the desired manner. PQ can be roughly broken into categories viz, steady-state voltage magnitude and frequency, voltage sags, grounding, harmonics, voltage fluctuations and flicker, transients, and monitoring and measurement.

The IEEE has produced numerous standards relating to the various PQ phenomena. Of these many standards, the one most appropriate to power electronic equipment is IEEE Standard 519-1992 [2]. IEEE 519-1992 established the Point of Common Coupling (PCC) as the point at which harmonic limits are evaluated.

1.2 Overview of Renewable Energy

Recently, the advisory group of United Kingdom (UK) renewable energy explained the renewable energy used to cover those energy flows, which occur naturally and repeatedly in the environment and can be harnessed for benefit of human. The ultimate sources of most of this energy are the sun, gravity and the earth’s rotation. Most renewable energy sources are derived from solar radiation, including the direct use of solar energy for heating or electricity generation, and indirect forms such as energy from wind, waves and running water. Tidal source of energy result from gravitational pull of the moon and sun, and geothermal energy comes from the heat generated within the earth.

Further to the technology development, the renewable sources range from technologies those are well established and mature to those that need further research and development. The use of renewable on a more significant scale than at present would at the very least replace a further significant proportion of fossil and nuclear fuel use, thereby reducing the associated environmental impacts. In this scenario, whole world focusing mainly solar, wind and fuel cell type renewable energy source because of their advantages such easy operation and maintenance, efficiency of generations, plant and availability of resources.

Wind energy: A moving object possesses kinetic energy due to its motion. Similarly, the flow of air around the earth, or wind, possesses kinetic energy, which is called wind energy. The flow of wind in our atmosphere is mainly caused by uneven heating of earth’s surface by the sun. Thus, wind energy is an indirect manifestation of the sun’ energy. The wind energy has the good potential which can be a source of renewable and pollution free power. It has been seen that about 1% to 3% of the solar energy falling on the earth’s surface is converted into wind energy. The kinetic energy of blowing wind can be converted to mechanical energy and then to electrical energy. Globally, the wind energy has been a successful alternative technology for generation of electrical energy. Very large capacity wind turbine, in the range of several MW, has been developed which are successfully employed for electric power generation. Wind power is categorized as distributed generation, stand-alone generation and grid connected electric power sources. The worldwide cumulative installed is now nearly about 400 GW (at the end of 2015).

Solar energy: The natural sunlight can be converted to electric power by PV effect, which was discovered in 1839, by Edmund Becquerel, a French scientist. The sunlight is composed of photons or packets of energy. These photons contain various amounts of electric energy which corresponds to the different wavelengths of light. When these photons strike a solar PV cell (a semiconductor p-n junction device), they may be reflected or absorbed, or they may be passing through the solar PV cell. The absorption of a photon in a solar PV cell results in generation of electron-hole pairs. The current flows in an external circuit when the electron-hole pair separated from each other. The electric power can be extracted from the solar PV cell, which is now referred to as a PV device. However, the last 20 years have seen large improvements in solar technology, with the best confirmed solar PV cell efficiency being over 24%. Over recent years, good progress has been made in transferring some of the corresponding design improvements into commercial products with cell of 17%-18% efficiency now being commercially available. Modeling of PV module and PV array is described in chapter 2 section in detail. PV systems can be used as grid connected PV system, stand-alone PV system and hybrid PV system.

1.3 Relevance of Renewable Energy in India

India has a vast supply of renewable energy resources, and it has one of the largest programs in the world for developing renewable energy based product and systems. India is a developing and fast growing large economy and faces a great challenge to meet its energy needs in a responsible and sustainable manner.

1.3.1 Grid-interactive renewable power

Grid-interactive renewable power capacity in the country reached 75,760 MW on 31st December 2018 (Table 1.1), which is around 20% of the total grid installed capacity in the country. Out of which the capacity of solar PV grid connected plants is around 26,025.97 MW. By 2022, the Government of India plans to increase the solar PV capacity to 1,00,000 MW.

Table 1.1: Plan wise capacity addition in grid connected renewable capacity [3]

Abbildung in dieser Leseprobe nicht enthalten

1.3.2 Off-Grid Renewable Power

In addition to grid connected renewable power, there is off grid or distributed and decentralized renewable power generation in country. It is beneficial, where grid power is not available easily. It provides energy access to large rural populations including those in inaccessible areas and meeting unmet demand in many other areas. Perhaps the remote areas can get electricity only though renewable sources. Table 1.2 presents a summary of achievements in off-grid or distributed electric power.

Table 1.2: Off-Grid / Captive Renewable Power [3]

Abbildung in dieser Leseprobe nicht enthalten

1.4 Chapter Conclusion

This chapter has mainly discussed the scenario of the renewable energy, highlighting potential of solar energy sector in India. The various steps being taken by the Government of India are also highlighted.

Chapter 2

INTRODUCTION TO CUSTOM POWER DEVICES

2.1 Introduction

Hingorani, who introduced the concept of custom power “as the solution to V (voltage), P (active power), and Q (reactive power) compensation and various PQ problems at the expense of high cost and network complexity”. The various Flexible AC Transmission Systems (FACTS) controllers improve the reliability and quality of electric power transmission by enhancing both power transfer capacity and stability, simultaneously. As compared, the Custom Power Devices (CPD) enhance the quality and reliability of electric power delivered to the customer. With a custom power device installed, a customer or any sensitive load is able to receive a pre-specified quality of electric power. It includes the low harmonic distortion in the supply, load voltages, and currents, small phase imbalance, and low flicker in the system supply voltage.

Classification of CPD are based on their power electronic controllers, which can be either of the network reconfiguration type or of the compensation type. The network reconfiguration devices which is also called switchgear, include the solid state and or static versions or current limiting, current transferring components and current breaking. The compensation type CPD is to either compensate a load (e.g., correction of power factor, or imbalance) or improve the PQ in system supply voltage (e.g., elimination of harmonics). These devices are either connected in parallel or in series or a combination of both. CPD devices are classified as follows:

- Network-reconfiguration CPD include Solid State Current Limiter (SSCL), Solid–State Breaker (SSB), and Solid State Transfer Switch (SSTS).
- Compensation- CPD include Distribution-STATCOM, DVR, and UPQC.

CPD are designed to improve the PQ at the point of installation of the power distribution system. They are not primarily designed to improve the PQ of the entire system.

2.2 Introduction to D-STATCOM

A Distribution-STATCOM (D-STATCOM) is a shunt compensation device used for reactive power compensation. It can be used either in the power factor correction mode or in the voltage regulation mode. The major problem associated with the design of the controller for the DSTATCOM is the selection of appropriate circuit components. The second major problem is to understand the proper working of the controller and control algorithms.

A D-STATCOM is a shunt connected Flexible AC Transmission System (FACTS) controller used for improving the PQ in the distribution level or at the medium voltage level. Figure 2.1 shows a D-STATCOM configuration which consists of a VSC or an inverter, a DC-link capacitor and a coupling inductor. The design of the D-STATCOM means the selection of appropriate values of coupling inductor or choke, determining the capacitor value and its operating voltage level and selecting the appropriate operating voltage and current ratings for the power electronic switches. In general, for medium voltage applications, Insulated Gate Bipolar Junction Transistors (IGBTs) are used as power electronic switches.

Abbildung in dieser Leseprobe nicht enthalten

Figure 2.1 Configuration of a D-STATCOM

2.3 Introduction to Unified Power Quality Conditioner (UPQC)

UPQC are viable compensation CPD that ensure that delivered electric power meets all required standards and specifications at point of installation. The ideal UPQC can be represented as the combination of a VSC (Voltage Source Converter) - (injecting shunt current) and a common DC link (connected to a DC capacitor), Figure 2.2.

Abbildung in dieser Leseprobe nicht enthalten

Figure 2.2 Basic Configuration of UPQC [4]

The UPQC consist of combined series active power filter that compensates voltage harmonics of the power supply, and shunt active power filter that compensates harmonic currents of a non-linear load. This dual functionality makes it as one of the most suitable CPD that can solve the problems of both consumers and utility. It thus, helps to improve voltage profile and reliability, hence, an overall health of electric power distribution system.

2.4 Basic configuration of UPQC

The main components of open type UPQC are series and shunt power converters Sethi [5], DC capacitors, low-pass and high-pass passive filters, and series and shunt transformers:

2.4.1 Series converter

It is the VSC connected which in series with the AC line and acts as a voltage source to mitigate the voltage distortions. It eliminates supply voltage fluctuations from the load terminal voltage and forces the shunt branch to absorb current harmonics generated by the non-linear load. Control of the series converter output voltage is usually performed using Sinusoidal Pulse-Width Modulation (SPWM). The gate pulses are generated by the comparison of a fundamental voltage reference signal with a high-frequency triangular waveform, Haque, and Hosseini [6].

2.4.2 Shunt converter

It is the voltage-source converter connected in shunt with the same AC line and acts as a current source to cancel current distortions to compensate reactive current of the load and to improve the power factor. It also performs the DC-link voltage regulation, results the significant reduction of the DC capacitor rating. The output current of the shunt converter is adjusted -by controlling the status of semiconductor switches such that output current follows the reference signal and remains in a predetermined hysteresis band.

2.4.3 Midpoint-to-ground DC capacitor bank

It is divided into two groups which are connected in series. The neutrals of the secondary transformers are directly connected to the DC link midpoint. As the connection of both three-phase transformers is Y/Yo the zero-sequence voltage appears in the primary winding of the series-connected transformer in order to compensate for the zero-sequence voltage of the supply system. No zero-sequence current flows in the primary side of both transformers. It ensures the system current to be balanced even when the voltage disturbance occurs.

2.4.4 Low-pass filter

It is used to attenuate high frequency components at the output of the series converter that are generated by high-frequency switching.

2.4.5 High-pass filter

It is installed at the output of shunt converter to absorb current switching ripples.

2.4.6Series and Shunt transformers

These are implemented to inject the compensation voltages and currents, and for the purpose of electrical isolation of UPQC converters. The UPQC is capable of steady-state and dynamic series and/or shunt active and reactive power compensations at fundamental and harmonic frequencies. However, the UPQC is only concerned about the quality of the load voltage and the line current at the point of its installation, and it does not improve the PQ of the entire system.

2.5 Functions performed by UPQC

The typical functions performed by UPQC are briefed below:

- It converts the feeder (system) current to balanced sinusoids through a shunt compensator, Khadkikar, [7].
- It converts the system load voltage to balanced sinusoids through a series compensator.
- It ensures the zero real power injection (and/or absorption) by the compensators.
- It supplies reactive power to the load (reactive power compensation).

Chapter 3

FAULT ANALYSIS OF POWER CONDITIONING SYSTEMS

3.1 Introduction

This chapter presents the three-phase fault analysis of solar PV grid tied systems in which two PV arrays of 45 kW each has been implemented. Harmonic analysis for important parameters has been done in simulink environment. Real and reactive power control has been demonstrated among load, utility grid and Insulated Gate Bipolar Transistor (IGBT) based Voltage Source Converter (VSC).

3.2 Controlling Approach in Simulation Model

Proportional Integral (PI) based voltage and current controllers are used whose chosen values are given in Table 3.1. PI controller has been taken as it reduces the steady-state error of the incoming actuating signal. Phase Locked loop (PLL) approach has been integrated through which synchronization of the VSC with utility grid has been done. Synchronous reference frame theory has been implemented, which converts any three-phase sinusoidal signal into two signals: d (direct axis) -q (quadrature axis). Through this approach, it becomes easy to analyze steady state signals. The gate of IGBT has been triggered through the Pulse Width Modulation (PWM) signal generator, which generates the signal corresponding to modulation index.

As shown in Figure 3.1, two solar PV arrays are connected to DC-DC boost converter. Since the solar radiation is variable, it is important to control the variable DC voltage to VSC. This is controlled by implementing Incremental Conductance (IC) based Maximum Power Point Tracking (MPPT) technique. Multi-string topology is used according to which a common VSC based inverter is used. Inductance-Capacitance (LC) is used after the IGBT based VSC which removes the harmonics from the VSC output voltage and current. A transformer of distribution type is used which steps down the voltage at level of utility grid of 440 V.

Abbildung in dieser Leseprobe nicht enthalten

Figure 3.1 Simulation model of solar PV grid tied system with connected load

Table 3.1 also shows the linear load values according to which the maximum real power requirement is 72 kW. Table 3.2 shows the solar PV manufacturer data sheet Kyocera KD135GX-LP, which can easily generate the accurate and validated results.

Table 3.1: Parameters of PV grid connected system

Abbildung in dieser Leseprobe nicht enthalten

Table 3.2: Specifications adopted for single PV array (Kyocera KD135GX-LP) [8]

Abbildung in dieser Leseprobe nicht enthalten

3.3 Simulation Results and Discussion

The simulation model shown in Figure 3.1 has been simulated for the 0.3 seconds. A three-phase fault has been introduced in B phase of the distribution line in between the three-phase transformer and grid. The fault resistance and ground resistance are 0.064 Ω and 0.0009 Ω, respectively. The ode45 Dormand-Prince solver has been chosen from the solver options of Matlab, which is of type variable step. In this section, the main study is carried out without the application of D-STATCOM on the utility grid side in the presence of three-phase fault at fundamental frequency.

As shown in Figure 3.2 (a), the waveform of DC-AC three-phase VSC converter current is shown during the effect of three-phase fault. The faulted period during which the fault has been introduced is 0.1 seconds to 0.2 seconds. The current which flows during this period is reduced as compared to non-faulted period. Similarly, the impact of three-phase fault is clearly evident from Figure 3.2 (b) which shows for DC-AC three-phase converter voltage. Sag (one of important PQ parameter) is observed in the waveforms for all phases for current, whose value is more than 3 per unit.

Abbildung in dieser Leseprobe nicht enthalten

(a)

Figure 3.2 (c) and Figure 3.2 (d) demonstrates the effect of three-phase fault on three-phase linear load current and load voltage at fundamental frequency. Figure 3.2 (e) and Figure 3.2 (f) demonstrates the effect of three-phase fault on three-phase utility grid current and utility grid voltage. Figure 3.3 (a) analyze the duty cycle of DC-DC boost converter whereas Figure 3.3 (b) shows the comparison of practical DC link voltage to VSC (shown by blue line) with MPPT base or reference voltage (shown by green line). The base voltage of 200 V clearly tracks the practical voltage however, with some transients due to the effect of three-phase fault. Figure 3.4 (a) presents the active power behavior for three-phase VSC, linear load and utility grid, whereas Figure 3.4 (b) presents the reactive power during the faulted period.

[...]

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Details

Title
Matlab Simulations Using D-STATCOM and UPQC in Solar Photovoltaics. A Power Quality Analysis
College
I. K. Gujral Punjab Technical University
Course
Electrical Engineering
Author
Year
2019
Pages
60
Catalog Number
V459601
ISBN (eBook)
9783668878198
ISBN (Book)
9783668878204
Language
English
Tags
matlab, simulations, using, d-statcom, upqc, solar, photovoltaics, power, quality, analysis
Quote paper
Akhil Gupta (Author), 2019, Matlab Simulations Using D-STATCOM and UPQC in Solar Photovoltaics. A Power Quality Analysis, Munich, GRIN Verlag, https://www.grin.com/document/459601

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