This document discusses methods for detecting and classifying disturbances in a hybrid distributed power system using wavelet transform and artificial neural networks. It begins by introducing the motivation for distributed generation and some challenges like unintentional islanding. It then describes using the wavelet transform on voltage signals to detect islanding and compares this to using total harmonic distortion. Statistical indices from the wavelet transform are used as inputs to an artificial neural network classifier to identify different disturbances like islanding, faults, and load changes with over 95% accuracy. The study concludes the wavelet transform approach provides better detection and classification than conventional techniques. Future work could explore improving performance under noisy conditions and different feature selection.
Process Variation Aware Crosstalk Mitigation for DWDM based Photonic NoC Arch...Ishan Thakkar
Photonic network-on-chip (PNoC) architectures are a potential candidate for communication in future chip multi-processors as they can attain higher bandwidth with lower power dissipation than electrical NoCs. PNoCs typically employ dense wavelength division multiplexing (DWDM) for high bandwidth transfers. Unfortunately, DWDM increases crosstalk noise and decreases optical signal to noise ratio (SNR) in microring resonators (MRs) threatening the reliability of data communication. Additionally, process variations induce variations in the width and thickness of MRs causing shifts in resonance wavelengths of MRs, which further reduces signal integrity, leading to communication errors and bandwidth loss. In this paper, we propose a novel encoding mechanism that intelligently adapts to on-chip process variations, and improves worst-case SNR by reducing crosstalk noise in MRs used within DWDM-based PNoCs. Experimental results on the Corona PNoC architecture indicate that our approach improves worst-case SNR by up to 44.13%.
Signal Integrity - A Crash Course [R Lott]Ryan Lott
This document provides an introduction to signal integrity for interconnects. It discusses typical interconnects like PCB traces, cables, and connectors and the signal integrity problems they can cause, such as loss, reflections, crosstalk, and ringing. It also introduces concepts like characteristic impedance, frequency-dependent loss, and how signals propagate as electromagnetic waves. Measurement techniques like S-parameters and using a vector network analyzer are discussed as ways to characterize devices in the frequency domain.
The Approach on Influence of Biasing Circuit in Wideband Low Noise Amplifier ...IJEACS
This proposed work investigates the effects of biasing
circuit in the ultra-wideband microwave low noise amplifier
which operates between 3GHz to 10GHz. The complete circuit is
visualized the importance of every component in the design with
respect to linear measurements like Gain, Noise Figure, Return
loss under unconditionally stable condition. The design and
realization are made by using Hybrid Microwave integrated
circuit in AWR microwave office. The thing that is absolutely
necessary and frequently the difficult step in the design of an
LNA is 'biasing circuit design'. The difficulty situation arises
because traditional methods LNA by using S-parameters data
files in EDA tools provides almost all linear measurements.
Hence a number of time consuming iterations of different biasing
circuits with optimization methods may be required to reach
targeted specifications with the fixed operating point at the
desired points in the load line. Considering this behavior, various
alternate biasing circuit schemes are prepared and founded the
results associated with it. Furthermore, this paper unmistakably
clarifies the impacts of the biasing circuit by utilizing
intermodulation and harmonics distortion technique for
portrayal characterization. Different cases and sorts of the
biasing circuits with various biasing focuses have been tested and given clear perspective of the biasing ideas.
This document provides an agenda for a presentation on signal integrity that includes: defining signal integrity and why it is important; methods for signal integrity analysis including analytical, measurement, and simulation; modeling transmission lines and reflections; analyzing power planes and power integrity; and characteristics needed for successful signal and power integrity analysis and system design. Examples are provided throughout to illustrate key concepts.
This document describes a student project to implement frequency shift keying (FSK) modulation using two 555 timer circuits. The first 555 timer generates a digital signal at a defined frequency. The second 555 timer circuit modulates this signal to shift between two mark-space frequencies, controlled by a BC-547 transistor switching between logic 1 and 0 levels. The project analyzes the circuit operation and resulting modulated signal. Applications of FSK modulation discussed include early modems, radio transmission, and local area networks.
Chapter 2 passive components, resonators and impedance matchingkiên lý
This document is a chapter from a textbook on electronic circuits for communication written by Dr. Cuong Huynh from the Telecommunications Department at HCMUT. The chapter discusses passive components, resonators, and impedance matching. It covers the high frequency characteristics of passive components like resistors, capacitors, and inductors. It also discusses series and parallel RLC resonator circuits and their quality factors. Impedance transformations between series and parallel circuits are described while maintaining the same quality factor value.
This document discusses different types of transit time devices, focusing on IMPATT diodes. It describes the basic operation of IMPATT diodes, including how transit time and avalanche effects produce negative resistance and microwave oscillation. It covers different IMPATT diode designs like SDR, DDR, and DAR, and discusses their characteristics, materials used, efficiency, advantages and disadvantages. The document also briefly covers other transit time devices like BARITT, TRAPATT, and their operating principles and applications.
1. The document describes a self-adjusting optical serrodyne loop frequency shifter that uses a DQPSK modulator to generate a spectrum of optical carrier frequencies for testing high data rate transmission.
2. A biasing technique was studied that uses asymmetric dither signals to monitor and optimize the bias points of the DQPSK modulator in order to produce a clean optical frequency shift. This technique was simulated and a system was designed using an FPGA to implement it.
3. Testing showed that optimizing the bias points reduced output power and suppressed unwanted frequencies when no RF was applied, and produced a single sideband shift when RF was on, enabling generation of multiple optical subcarriers.
Process Variation Aware Crosstalk Mitigation for DWDM based Photonic NoC Arch...Ishan Thakkar
Photonic network-on-chip (PNoC) architectures are a potential candidate for communication in future chip multi-processors as they can attain higher bandwidth with lower power dissipation than electrical NoCs. PNoCs typically employ dense wavelength division multiplexing (DWDM) for high bandwidth transfers. Unfortunately, DWDM increases crosstalk noise and decreases optical signal to noise ratio (SNR) in microring resonators (MRs) threatening the reliability of data communication. Additionally, process variations induce variations in the width and thickness of MRs causing shifts in resonance wavelengths of MRs, which further reduces signal integrity, leading to communication errors and bandwidth loss. In this paper, we propose a novel encoding mechanism that intelligently adapts to on-chip process variations, and improves worst-case SNR by reducing crosstalk noise in MRs used within DWDM-based PNoCs. Experimental results on the Corona PNoC architecture indicate that our approach improves worst-case SNR by up to 44.13%.
Signal Integrity - A Crash Course [R Lott]Ryan Lott
This document provides an introduction to signal integrity for interconnects. It discusses typical interconnects like PCB traces, cables, and connectors and the signal integrity problems they can cause, such as loss, reflections, crosstalk, and ringing. It also introduces concepts like characteristic impedance, frequency-dependent loss, and how signals propagate as electromagnetic waves. Measurement techniques like S-parameters and using a vector network analyzer are discussed as ways to characterize devices in the frequency domain.
The Approach on Influence of Biasing Circuit in Wideband Low Noise Amplifier ...IJEACS
This proposed work investigates the effects of biasing
circuit in the ultra-wideband microwave low noise amplifier
which operates between 3GHz to 10GHz. The complete circuit is
visualized the importance of every component in the design with
respect to linear measurements like Gain, Noise Figure, Return
loss under unconditionally stable condition. The design and
realization are made by using Hybrid Microwave integrated
circuit in AWR microwave office. The thing that is absolutely
necessary and frequently the difficult step in the design of an
LNA is 'biasing circuit design'. The difficulty situation arises
because traditional methods LNA by using S-parameters data
files in EDA tools provides almost all linear measurements.
Hence a number of time consuming iterations of different biasing
circuits with optimization methods may be required to reach
targeted specifications with the fixed operating point at the
desired points in the load line. Considering this behavior, various
alternate biasing circuit schemes are prepared and founded the
results associated with it. Furthermore, this paper unmistakably
clarifies the impacts of the biasing circuit by utilizing
intermodulation and harmonics distortion technique for
portrayal characterization. Different cases and sorts of the
biasing circuits with various biasing focuses have been tested and given clear perspective of the biasing ideas.
This document provides an agenda for a presentation on signal integrity that includes: defining signal integrity and why it is important; methods for signal integrity analysis including analytical, measurement, and simulation; modeling transmission lines and reflections; analyzing power planes and power integrity; and characteristics needed for successful signal and power integrity analysis and system design. Examples are provided throughout to illustrate key concepts.
This document describes a student project to implement frequency shift keying (FSK) modulation using two 555 timer circuits. The first 555 timer generates a digital signal at a defined frequency. The second 555 timer circuit modulates this signal to shift between two mark-space frequencies, controlled by a BC-547 transistor switching between logic 1 and 0 levels. The project analyzes the circuit operation and resulting modulated signal. Applications of FSK modulation discussed include early modems, radio transmission, and local area networks.
Chapter 2 passive components, resonators and impedance matchingkiên lý
This document is a chapter from a textbook on electronic circuits for communication written by Dr. Cuong Huynh from the Telecommunications Department at HCMUT. The chapter discusses passive components, resonators, and impedance matching. It covers the high frequency characteristics of passive components like resistors, capacitors, and inductors. It also discusses series and parallel RLC resonator circuits and their quality factors. Impedance transformations between series and parallel circuits are described while maintaining the same quality factor value.
This document discusses different types of transit time devices, focusing on IMPATT diodes. It describes the basic operation of IMPATT diodes, including how transit time and avalanche effects produce negative resistance and microwave oscillation. It covers different IMPATT diode designs like SDR, DDR, and DAR, and discusses their characteristics, materials used, efficiency, advantages and disadvantages. The document also briefly covers other transit time devices like BARITT, TRAPATT, and their operating principles and applications.
1. The document describes a self-adjusting optical serrodyne loop frequency shifter that uses a DQPSK modulator to generate a spectrum of optical carrier frequencies for testing high data rate transmission.
2. A biasing technique was studied that uses asymmetric dither signals to monitor and optimize the bias points of the DQPSK modulator in order to produce a clean optical frequency shift. This technique was simulated and a system was designed using an FPGA to implement it.
3. Testing showed that optimizing the bias points reduced output power and suppressed unwanted frequencies when no RF was applied, and produced a single sideband shift when RF was on, enabling generation of multiple optical subcarriers.
Webinar Slides: Digital Power Management and Power Integrity Analysis and Tes...teledynelecroy
Join Teledyne LeCroy for an overview of digital power management, power integrity, and power sequencing. We'll discuss test of single or multi-phase digital power management ICs (PMICs), voltage regulator modules (VRMs), point-of-load (POLs) switching regulators, low-dropout (LDO) regulators or other DC-DC converter operations under transient load conditions, and test of complete embedded systems that contain these devices.
Dispersion Compensation Module for WDM -PON at 5 -GB/S Downstream with Variou...IRJET Journal
This document discusses dispersion compensation in wavelength division multiplexing passive optical networks (WDM-PONs) operating at 5 Gbps downstream transmission. It simulates various modulation formats, including duobinary, differential phase shift keying (DPSK), and on-off keying (OOK) to increase data speeds over different transmission distances. The combination of 87.5 km standard single mode fiber and 12.5 km dispersion compensating fiber is used to transmit over a total of 100 km while maintaining a low bit error rate and high Q factor. Dispersion compensation fibers are employed to counteract chromatic dispersion accumulated over long reaches of single mode fiber.
This document analyzes very fast transient overvoltages (VFTOs) in transformers in 400kV gas insulated substations (GIS) using wavelet transforms. It presents a model of a three-phase, two-winding transformer designed in MATLAB Simulink to simulate VFTOs generated by circuit breaker operations under open and closing conditions. Wavelet transform analysis is applied to the results to investigate suppression of overvoltage magnitudes and resonant frequency amplitudes. The analysis shows the proposed technique provides high accuracy in mitigating VFTOs using wavelet transforms.
The document summarizes research on comparing the performance of different adaptive beamforming algorithms for smart antenna systems. Simulation results showed that training sequence algorithms like recursive least squares (RLS) and least mean squares (LMS) formed the best main lobes towards the desired user but had limitations in interference rejection. The constant modulus algorithm (CMA) provided better interference rejection but a higher bit error rate for a single antenna element. RLS was found to have the fastest convergence rate, making it the best choice. Increasing the step size for LMS affected its performance. Overall, RLS was found to perform best across parameters like beampattern, amplitude response, error, and bit error rate.
This document discusses intelligent reflecting surfaces (IRS), which are metasurfaces that can control the amplitude and phase of reflected wireless signals. An IRS consists of many small elements that each scatter incoming waves. By adjusting the individual element properties, the overall reflected signal can be constructively or destructively combined to focus energy towards or away from users. IRS technology could improve coverage and capacity for wireless networks by optimizing signal propagation through coherent beamforming based on estimated channel state information. Open challenges include developing efficient channel estimation techniques and determining optimal placements of IRS arrays within wireless environments.
The document discusses the design and implementation of a P-band RF low noise amplifier (LNA). It begins with an introduction to LNAs, explaining that their main function is to amplify weak signals while introducing minimal noise. It then discusses the use of pseudomorphic high electron mobility transistors (pHEMTs) for LNA design due to their ability to provide high gain and low noise figure. The document outlines the objectives and methodology for the project, which is to design an LNA with specifications including a frequency range of 50MHz-1GHz, gain of at least 22dB, noise figure below 4dB and input/output impedance of 50 ohms. It provides background on relevant LNA design concepts and
This document presents the design of a phased array antenna system using phase shifters. A group of 4 students designed and simulated a 1x4 microstrip patch antenna array fed by a Wilkinson power divider in ADS software. They first designed a single rectangular patch antenna, then a 1:4 Wilkinson power divider and combined them into an antenna array. Phase shifters using varactor diodes were also designed and simulated for different voltage biases. The phase and insertion loss characteristics of the phase shifters were analyzed to verify their performance in the phased array system.
Join Teledyne LeCroy for a discussion of what S-parameters are and why we should care about them. As serial data rates move into the multi-gigabit domain, S-parameters play an important role in understanding system performance. We will uncover the four main patterns found in s-parameters and learn what they can tell us about our interconnects.
The document summarizes a research project on multi-resolution data fusion using agent-based sensors. The project aims to develop collaborative signal processing techniques that are energy-aware, fault-tolerant, and progressively improve accuracy. Key accomplishments include developing mobile agent-based collaborative signal processing, energy-aware task scheduling algorithms, analytical battery modeling, and sensor deployment algorithms. The project has resulted in several publications and integrated some techniques successfully, while other integration efforts faced challenges.
Wavelength converters are devices that convert data from one incoming wavelength to another wavelength. They enable optical channels to be relocated and are achieved using nonlinear optical effects. Wavelength converters are useful in WDM networks for three reasons: 1) data may enter the network at an unsuitable wavelength, 2) converters may improve wavelength utilization on network links, and 3) converters may be needed when networks managed by different entities do not coordinate wavelength allocation. Common types of wavelength converters include optoelectronic, optical gating using cross-gain modulation, and four-wave mixing approaches.
Enhancement Power Quality with Sugeno-type Fuzzy Logic and Mamdani-type Fuzzy...Mohamed Khaleeel
Power quality is closely related issues of most directly affect nowadays. It can be clear that electrical power quality is the degree of any deviation from the nominal rate of the voltage magnitude and frequency. Voltage sagis one of the most significant power quality problems challenging at present time. This paper discussed modeling of a DVR with PI controller, Sugeno-type Fuzzy Logic and Mamdani-type Fuzzy Logic using Matlab/Simulink in order to mitigate voltage sag. Then analyze the performance of DVR in order to solve the problem of voltage sag by installed DVR between the supply voltage and a sensitive load.
This document discusses the design and performance analysis of an optical transmission system using different modulation formats. It simulates a long-haul optical transmission system over single-mode fiber. Return-to-zero (RZ) and non-return-to-zero (NRZ) modulation formats are analyzed at 10Gb/s. The performance is investigated based on parameters like Q-factor, bit error rate, eye diagrams, and input power. Simulation results show that RZ modulation has better performance for long-distance transmission systems due to its lower bit error rate, while NRZ is suitable for shorter distances due to its smaller bandwidth requirements.
The document discusses beamforming antennas and their applications. It begins by outlining beamforming concepts and configurations like phased arrays and adaptive arrays. It then discusses applications of beamforming antennas in areas like radar, sonar, communications and imaging. Specific examples covered include phased array radar, neuronal spike sorting, and smart antenna systems for wireless networks. Vector antennas and their advantages over phased arrays are also summarized. Finally, the document discusses potential uses and challenges of beamforming antennas for wireless ad hoc networks.
(1) This document discusses implementing discrete wavelet transformation (DWT) using VHDL for power system analysis. DWT provides time-frequency localization and can detect minor faults in power transformers. VHDL is used to design a digital DWT architecture on FPGA for improved efficiency over traditional methods. (2) The architecture performs multi-level DWT decomposition using high pass and low pass filters to extract detail and approximation coefficients from input signals. (3) This allows more accurate fault detection compared to conventional spatial analysis and can provide faster response for electrical equipment monitoring than existing DSP or filter chip methods.
The document describes a simulation project for a communication link using AM and PSK modulation. Students are asked to design and simulate a communication link using AM modulation to transmit an audio signal, investigating the effects of different message signal frequencies and modulation indices. They also simulate communication links using BPSK and QPSK modulation schemes, comparing the performance of each in terms of bandwidth efficiency and required signal power. The project uses Matlab and Simulink to generate signals, design modulators and demodulators, and simulate the overall communication links.
Digital communication viva questions.( 50+)
MCQ of digital communication (50+)
communication systems MCQ. (50+)
communication systems viva questions (50+)
covered topic list:
sampling,quantization,digital,discrete,AM,FM,PM,ASK,FSK,PSK,DM,DPCM,QPSK,ADM,differences,modulation,block diagram,applications,PAM,PWM,PPM,line encoding,polar encoding,bipolar encoding,unipolar encoding,RZ,NRZ,AMI,HDB3,B8ZS
This document discusses using electronic feedback to induce self-pulsation in a distributed feedback laser diode for use in photonic analog-to-digital conversion. It presents a theoretical model and simulation results showing that:
1) Electronic feedback can increase the relaxation oscillation frequency and modulation bandwidth of the laser diode compared to operating without feedback.
2) Increasing the feedback delay beyond a certain point induces self-pulsation, extracting pulses from the relaxation oscillation with intervals tunable by the bias current.
3) Self-pulsation produces an optical output spectrum with mode spacing that increases with bias current, showing potential as a tunable pulsing source for photonic analog-to-digital converters.
Low Noise Amplifier at 2 GHz using the transistor NE85639 in ADSKarthik Rathinavel
• Systematically designed a LNA and its biasing using non-ideal components such as Microstrip TLs resistors, capacitors etc.
• Calculated the S parameters of the Transistor and simulated the gain and bandwidth to be 10 dB and 1 GHz respectively.
• Achieved a Noise Figure of 3.2 dB and s11 of -20 dB in the final design.
Optical power debugging in dwdm system having fixed gain amplifierseSAT Journals
Abstract
This article covers optical power measurement of light signal in DWDM network and debugging of optical power as per the specifications of DWDM system with fix gain amplifier. The measurement and calculations of each component of DWDM system is discussed individually. Optical power of individual optical channel, aggregate optical power of multiplexed signals, relation with amplifier gain, insertion loss and attenuation on signal are the key factors involved in design and operation of DWDM system. From transmitter to receiver, the working performance of the DWDM system depends on the optical strength of input light signal should be as per specifications of its components. A description of input and output optical power of light signal of each DWDM component and its relationship is discussed. If there is any deviation as per specifications is observed, process to calculate deviation and debug is given with working example in this article.
Keywords: Dense wavelength division multiplexing (DWDM), Optical MUX/DEMUX, Optical transmitters/receivers, Optical amplifiers, Optical Fiber, Optical power, Attenuation, Optical Power Debugging
The document discusses different types of microwave phase shifters. It describes that a phase shifter is a two-port device that provides a fixed or variable phase shift of an RF signal with minimal attenuation. It then focuses on ferrite phase shifters, which use ferrite materials to provide a variable phase shift by changing the bias field of the ferrite. The document also discusses distributed phase shifters, active vs. passive phase shifters, analog vs. digital phase shifters, and fixed vs. variable phase shifters.
J. A. P. Lopes, "The MERGE control concept - Microgrids and EVs - Development...Eamon Keane
1. The document discusses a conceptual framework for integrating electric vehicles (EVs) into power systems through microgrids and aggregators.
2. A hierarchical control concept is proposed to manage EV charging and discharging across different grid levels from the distribution system operator down to individual EVs.
3. During normal grid operations, aggregators would participate in electricity markets on behalf of EVs. But in emergency situations, EVs would be controlled directly by distribution system operators to ensure stable microgrid operations.
This document summarizes research using power hardware-in-the-loop (PHIL) techniques to evaluate photovoltaic inverter island detection. It finds that PHIL methods provide reasonably similar results to standard RLC tank testing, and inverter island detection algorithms are robust against non-islanding distributed generation. However, induction motors can impact detection, with larger motors preventing detection. It concludes more research is needed to determine appropriate island detection performance standards and certification testing.
Webinar Slides: Digital Power Management and Power Integrity Analysis and Tes...teledynelecroy
Join Teledyne LeCroy for an overview of digital power management, power integrity, and power sequencing. We'll discuss test of single or multi-phase digital power management ICs (PMICs), voltage regulator modules (VRMs), point-of-load (POLs) switching regulators, low-dropout (LDO) regulators or other DC-DC converter operations under transient load conditions, and test of complete embedded systems that contain these devices.
Dispersion Compensation Module for WDM -PON at 5 -GB/S Downstream with Variou...IRJET Journal
This document discusses dispersion compensation in wavelength division multiplexing passive optical networks (WDM-PONs) operating at 5 Gbps downstream transmission. It simulates various modulation formats, including duobinary, differential phase shift keying (DPSK), and on-off keying (OOK) to increase data speeds over different transmission distances. The combination of 87.5 km standard single mode fiber and 12.5 km dispersion compensating fiber is used to transmit over a total of 100 km while maintaining a low bit error rate and high Q factor. Dispersion compensation fibers are employed to counteract chromatic dispersion accumulated over long reaches of single mode fiber.
This document analyzes very fast transient overvoltages (VFTOs) in transformers in 400kV gas insulated substations (GIS) using wavelet transforms. It presents a model of a three-phase, two-winding transformer designed in MATLAB Simulink to simulate VFTOs generated by circuit breaker operations under open and closing conditions. Wavelet transform analysis is applied to the results to investigate suppression of overvoltage magnitudes and resonant frequency amplitudes. The analysis shows the proposed technique provides high accuracy in mitigating VFTOs using wavelet transforms.
The document summarizes research on comparing the performance of different adaptive beamforming algorithms for smart antenna systems. Simulation results showed that training sequence algorithms like recursive least squares (RLS) and least mean squares (LMS) formed the best main lobes towards the desired user but had limitations in interference rejection. The constant modulus algorithm (CMA) provided better interference rejection but a higher bit error rate for a single antenna element. RLS was found to have the fastest convergence rate, making it the best choice. Increasing the step size for LMS affected its performance. Overall, RLS was found to perform best across parameters like beampattern, amplitude response, error, and bit error rate.
This document discusses intelligent reflecting surfaces (IRS), which are metasurfaces that can control the amplitude and phase of reflected wireless signals. An IRS consists of many small elements that each scatter incoming waves. By adjusting the individual element properties, the overall reflected signal can be constructively or destructively combined to focus energy towards or away from users. IRS technology could improve coverage and capacity for wireless networks by optimizing signal propagation through coherent beamforming based on estimated channel state information. Open challenges include developing efficient channel estimation techniques and determining optimal placements of IRS arrays within wireless environments.
The document discusses the design and implementation of a P-band RF low noise amplifier (LNA). It begins with an introduction to LNAs, explaining that their main function is to amplify weak signals while introducing minimal noise. It then discusses the use of pseudomorphic high electron mobility transistors (pHEMTs) for LNA design due to their ability to provide high gain and low noise figure. The document outlines the objectives and methodology for the project, which is to design an LNA with specifications including a frequency range of 50MHz-1GHz, gain of at least 22dB, noise figure below 4dB and input/output impedance of 50 ohms. It provides background on relevant LNA design concepts and
This document presents the design of a phased array antenna system using phase shifters. A group of 4 students designed and simulated a 1x4 microstrip patch antenna array fed by a Wilkinson power divider in ADS software. They first designed a single rectangular patch antenna, then a 1:4 Wilkinson power divider and combined them into an antenna array. Phase shifters using varactor diodes were also designed and simulated for different voltage biases. The phase and insertion loss characteristics of the phase shifters were analyzed to verify their performance in the phased array system.
Join Teledyne LeCroy for a discussion of what S-parameters are and why we should care about them. As serial data rates move into the multi-gigabit domain, S-parameters play an important role in understanding system performance. We will uncover the four main patterns found in s-parameters and learn what they can tell us about our interconnects.
The document summarizes a research project on multi-resolution data fusion using agent-based sensors. The project aims to develop collaborative signal processing techniques that are energy-aware, fault-tolerant, and progressively improve accuracy. Key accomplishments include developing mobile agent-based collaborative signal processing, energy-aware task scheduling algorithms, analytical battery modeling, and sensor deployment algorithms. The project has resulted in several publications and integrated some techniques successfully, while other integration efforts faced challenges.
Wavelength converters are devices that convert data from one incoming wavelength to another wavelength. They enable optical channels to be relocated and are achieved using nonlinear optical effects. Wavelength converters are useful in WDM networks for three reasons: 1) data may enter the network at an unsuitable wavelength, 2) converters may improve wavelength utilization on network links, and 3) converters may be needed when networks managed by different entities do not coordinate wavelength allocation. Common types of wavelength converters include optoelectronic, optical gating using cross-gain modulation, and four-wave mixing approaches.
Enhancement Power Quality with Sugeno-type Fuzzy Logic and Mamdani-type Fuzzy...Mohamed Khaleeel
Power quality is closely related issues of most directly affect nowadays. It can be clear that electrical power quality is the degree of any deviation from the nominal rate of the voltage magnitude and frequency. Voltage sagis one of the most significant power quality problems challenging at present time. This paper discussed modeling of a DVR with PI controller, Sugeno-type Fuzzy Logic and Mamdani-type Fuzzy Logic using Matlab/Simulink in order to mitigate voltage sag. Then analyze the performance of DVR in order to solve the problem of voltage sag by installed DVR between the supply voltage and a sensitive load.
This document discusses the design and performance analysis of an optical transmission system using different modulation formats. It simulates a long-haul optical transmission system over single-mode fiber. Return-to-zero (RZ) and non-return-to-zero (NRZ) modulation formats are analyzed at 10Gb/s. The performance is investigated based on parameters like Q-factor, bit error rate, eye diagrams, and input power. Simulation results show that RZ modulation has better performance for long-distance transmission systems due to its lower bit error rate, while NRZ is suitable for shorter distances due to its smaller bandwidth requirements.
The document discusses beamforming antennas and their applications. It begins by outlining beamforming concepts and configurations like phased arrays and adaptive arrays. It then discusses applications of beamforming antennas in areas like radar, sonar, communications and imaging. Specific examples covered include phased array radar, neuronal spike sorting, and smart antenna systems for wireless networks. Vector antennas and their advantages over phased arrays are also summarized. Finally, the document discusses potential uses and challenges of beamforming antennas for wireless ad hoc networks.
(1) This document discusses implementing discrete wavelet transformation (DWT) using VHDL for power system analysis. DWT provides time-frequency localization and can detect minor faults in power transformers. VHDL is used to design a digital DWT architecture on FPGA for improved efficiency over traditional methods. (2) The architecture performs multi-level DWT decomposition using high pass and low pass filters to extract detail and approximation coefficients from input signals. (3) This allows more accurate fault detection compared to conventional spatial analysis and can provide faster response for electrical equipment monitoring than existing DSP or filter chip methods.
The document describes a simulation project for a communication link using AM and PSK modulation. Students are asked to design and simulate a communication link using AM modulation to transmit an audio signal, investigating the effects of different message signal frequencies and modulation indices. They also simulate communication links using BPSK and QPSK modulation schemes, comparing the performance of each in terms of bandwidth efficiency and required signal power. The project uses Matlab and Simulink to generate signals, design modulators and demodulators, and simulate the overall communication links.
Digital communication viva questions.( 50+)
MCQ of digital communication (50+)
communication systems MCQ. (50+)
communication systems viva questions (50+)
covered topic list:
sampling,quantization,digital,discrete,AM,FM,PM,ASK,FSK,PSK,DM,DPCM,QPSK,ADM,differences,modulation,block diagram,applications,PAM,PWM,PPM,line encoding,polar encoding,bipolar encoding,unipolar encoding,RZ,NRZ,AMI,HDB3,B8ZS
This document discusses using electronic feedback to induce self-pulsation in a distributed feedback laser diode for use in photonic analog-to-digital conversion. It presents a theoretical model and simulation results showing that:
1) Electronic feedback can increase the relaxation oscillation frequency and modulation bandwidth of the laser diode compared to operating without feedback.
2) Increasing the feedback delay beyond a certain point induces self-pulsation, extracting pulses from the relaxation oscillation with intervals tunable by the bias current.
3) Self-pulsation produces an optical output spectrum with mode spacing that increases with bias current, showing potential as a tunable pulsing source for photonic analog-to-digital converters.
Low Noise Amplifier at 2 GHz using the transistor NE85639 in ADSKarthik Rathinavel
• Systematically designed a LNA and its biasing using non-ideal components such as Microstrip TLs resistors, capacitors etc.
• Calculated the S parameters of the Transistor and simulated the gain and bandwidth to be 10 dB and 1 GHz respectively.
• Achieved a Noise Figure of 3.2 dB and s11 of -20 dB in the final design.
Optical power debugging in dwdm system having fixed gain amplifierseSAT Journals
Abstract
This article covers optical power measurement of light signal in DWDM network and debugging of optical power as per the specifications of DWDM system with fix gain amplifier. The measurement and calculations of each component of DWDM system is discussed individually. Optical power of individual optical channel, aggregate optical power of multiplexed signals, relation with amplifier gain, insertion loss and attenuation on signal are the key factors involved in design and operation of DWDM system. From transmitter to receiver, the working performance of the DWDM system depends on the optical strength of input light signal should be as per specifications of its components. A description of input and output optical power of light signal of each DWDM component and its relationship is discussed. If there is any deviation as per specifications is observed, process to calculate deviation and debug is given with working example in this article.
Keywords: Dense wavelength division multiplexing (DWDM), Optical MUX/DEMUX, Optical transmitters/receivers, Optical amplifiers, Optical Fiber, Optical power, Attenuation, Optical Power Debugging
The document discusses different types of microwave phase shifters. It describes that a phase shifter is a two-port device that provides a fixed or variable phase shift of an RF signal with minimal attenuation. It then focuses on ferrite phase shifters, which use ferrite materials to provide a variable phase shift by changing the bias field of the ferrite. The document also discusses distributed phase shifters, active vs. passive phase shifters, analog vs. digital phase shifters, and fixed vs. variable phase shifters.
J. A. P. Lopes, "The MERGE control concept - Microgrids and EVs - Development...Eamon Keane
1. The document discusses a conceptual framework for integrating electric vehicles (EVs) into power systems through microgrids and aggregators.
2. A hierarchical control concept is proposed to manage EV charging and discharging across different grid levels from the distribution system operator down to individual EVs.
3. During normal grid operations, aggregators would participate in electricity markets on behalf of EVs. But in emergency situations, EVs would be controlled directly by distribution system operators to ensure stable microgrid operations.
This document summarizes research using power hardware-in-the-loop (PHIL) techniques to evaluate photovoltaic inverter island detection. It finds that PHIL methods provide reasonably similar results to standard RLC tank testing, and inverter island detection algorithms are robust against non-islanding distributed generation. However, induction motors can impact detection, with larger motors preventing detection. It concludes more research is needed to determine appropriate island detection performance standards and certification testing.
Modelling the system dynamics of islanding asynchronous generators / Telemark...Modelon
Study of Håkon Molland Edvardsen & Dietmar Winkler from Telemark University College
Norway (Modelica Conference 2014).
Modelon's Electric Power Library helps in the model-based reconstruction of events behind an earth circuit fault in Grunnåi, Norway.
Detection of Transmission Line Faults by Wavelet Based Transient ExtractionIDES Editor
This paper proposes a novel technique to detect faults in transmission lines using wavelet transform. Three-phase currents are monitored at both ends of the transmission line using GPS synchronization. Wavelet transform is used to extract transients from the current signals, which are indicative of faults. A fault index is calculated based on the detail coefficients of the wavelet transform and compared to a threshold value to detect faults. Simulation results demonstrate the technique can detect various faults at different locations and inception angles on the transmission line.
Signal-Energy Based Fault Classification of Unbalanced Network using S-Transf...idescitation
This document presents a technique for classifying faults on overhead transmission lines using S-Transform and a Probabilistic Neural Network (PNN) classifier. Voltage signals are processed using S-Transform to extract energy features from each phase. These 3 features (1 per phase) are used as inputs to a PNN classifier to determine the type of fault (e.g. line-ground, line-line) and faulty phase. The method was tested on a simulated 3-phase transmission line model in MATLAB with different fault conditions. It produced accurate classification results, even when noise was added to the signals. The paper concludes the method provides fast and accurate fault classification.
Principal component analysis (PCA) was used to analyze the conformational diversity of Ras proteins based on X-ray crystal structures. PCA separated the structures into two main clusters corresponding to the GTP-bound and GDP-bound conformations, capturing over 57.4% of the variance in the first two principal components. PCA loading plots identified displacements of switch regions as dominant features describing the conformational differences.
PCA was also used to analyze interactions between ligands and protein structures of CYP3A4 based on molecular interaction fields calculated using grid probes. Consensus PCA separated the structures based on differences in interactions with hydrophobic probes. PCA score plots distinguished the homology model from crystal structures based on interactions with Phe304, Thr309 and
1) The document discusses using discrete wavelet transforms to analyze vibration signals from roller bearings to detect faults. It proposes a new feature - summing the squared wavelet decomposition coefficients at each level - and compares it to the traditional energy-based feature.
2) An experiment is described where vibration signals are collected from a test rig under normal conditions and with introduced inner race, outer race, and combined faults. The signals are decomposed using discrete wavelet transforms.
3) Features are then extracted from the wavelet decompositions using both the proposed summed squared coefficient feature and the traditional energy-based feature. A decision tree is used to classify the features and determine which feature performs better at detecting the faults.
This document discusses synchronization failure detection between generators and the power grid using under voltage and over voltage detection. It defines synchronization as minimizing differences in voltage, frequency, and phase angle between a generator and the grid. Detection of synchronization failures is important to prevent issues like islanding where generators become disconnected from the main distribution lines. The document outlines various active and passive methods for detecting failures like impedance measurement, frequency shift, and under/over voltage and frequency protections. These detections are important for safety and to avoid power loss or consumption when failures occur.
Basics of process fault detection and diagnosticsRahul Dey
This document provides an overview of process fault detection and diagnostics. It discusses key topics such as fault detection vs diagnosis, abnormal event management, components of a fault diagnosis framework, classes of failures, and desirable characteristics of a fault diagnostics system. Quantitative model-based methods are also introduced, including the use of redundancy, Kalman filters, and residual generation in dynamic systems.
This document provides guidance on diagnosing and resolving various issues with landline phone and internet services. It includes steps to check for dial tone, static/noise, connection issues, speed tests, equipment setup and more. Technicians are instructed to have customers perform tests and try isolating the problem before lodging a fault if issues remain.
This document summarizes a research paper that proposes using an artificial neural network tuned by a simulated annealing algorithm for real-time credit card fraud detection. The paper describes how simulated annealing can be used to train the weights of a neural network model to classify credit card transactions as fraudulent or non-fraudulent based on attributes of past transactions. The algorithm is tested on a real-world credit card transaction dataset and is found to effectively classify most transactions correctly, though some misclassifications still occur.
This document summarizes an analysis comparing the primary leaf metabolites of pumpkin and tomatillo plants. The goal was to carry out statistical analyses, hierarchical cluster analysis (HCA), principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (O-PLS-DA) on metabolite profile data from pumpkin and tomatillo leaf samples. Both the HCA and PCA suggested that the treatment effect on metabolite profiles was minor compared to differences between species. A PLS-DA model was validated and found to have outstanding performance in discriminating between pumpkin and tomatillo leaf metabolites. Top discriminating metabolites between the species were then identified.
Introduction to principal component analysis (pca)Mohammed Musah
This document provides an introduction to principal component analysis (PCA), outlining its purpose for data reduction and structural detection. It defines PCA as a linear combination of weighted observed variables. The procedure section discusses assumptions like normality, homoscedasticity, and linearity that are evaluated prior to PCA. Requirements for performing PCA include the variables being at the metric or nominal level, sufficient sample size and variable ratios, and adequate correlations between variables.
SIGNAL PROCESSING TECHNIQUES USED FOR GEAR FAULT DIAGNOSISJungho Park
The slides are about signal processing techniques widely used for gear fault diagnosis (also the techniques could be used for other various rotating machine diagnosis such as bearing, rotor, motor, etc.). The techniques include wavelet transform, EMD (empirical mode decomposition), HHT (Hilbert-Huang transform), AR-MED filter, Spectral kurtosis, and cyclo-stationary analysis.
The document discusses a seminar presentation on Magneto Optical Current Transformers (MOCT). It begins with an introduction on the need for accurate current transformers and limitations of conventional transformers. It then covers the principles and workings of MOCT, which uses the Faraday effect to measure current through a glass prism. The document outlines the design, block diagram, applications and advantages of MOCT over conventional transformers, such as immunity to electromagnetic interference. It concludes by stating MOCT eliminates many drawbacks of conventional current transformers.
This document discusses using principal component analysis (PCA) to analyze metabolomic sample data from pumpkin experiments. PCA was performed on the raw data and scaled data to identify major sources of variance. For the raw data, the first two principal components captured most of the variance and separated samples by extraction method and treatment. Several samples were identified as potential outliers. When PCA was done on autoscaled data, the loadings showed differences due to both extraction and treatment. The scaled analysis also identified some outlier samples.
PCA transforms correlated variables into uncorrelated variables called principal components. It finds the directions of maximum variance in high-dimensional data by computing the eigenvectors of the covariance matrix. The first principal component accounts for as much of the variability in the data as possible, and each succeeding component accounts for as much of the remaining variability as possible. Dimensionality reduction is achieved by ignoring components with small eigenvalues, retaining only the most significant components.
The document presents a new topology for a submultilevel inverter and proposes connecting multiple submultilevel inverters in series to create a generalized multilevel inverter. The proposed multilevel inverter uses fewer switching devices than existing topologies and is analyzed under symmetric and asymmetric conditions. Simulation results using MATLAB-SIMULINK show the asymmetric 31-level inverter has distortion of only 0.2% using 12 switches, while the symmetric 13-level inverter has 0.8% distortion using 16 switches.
Amplification, ROADM and Optical Networking activities at CPqDCPqD
The document summarizes the amplification, ROADM, and optical networking activities at CPqD. It discusses the development of an automated amplifier characterizer, work on transient response issues in cascaded ROADMs, and dual-optimization algorithms for adaptive EDFA gain control and global WSS equalization. It also outlines collaboration with UTD on efficient numerical modeling of EDFA output power and network-wide signal power control strategies.
1) Analog to digital conversion involves sampling, quantizing, and encoding an analog signal to represent it as discrete digital values. Pulse code modulation is the most common technique which uses a low pass filter, sampler, and encoder.
2) Digital to analog conversion reconstructs the analog signal from discrete digital values using techniques like amplitude shift keying, frequency shift keying, and phase shift keying that modulate properties of a carrier signal.
3) A wireless sensor network is an ad hoc network of sensors that monitor physical conditions and communicate wirelessly, enabling applications in areas like environmental monitoring and healthcare. Challenges include energy efficiency, security, and coping with node failures.
IRJET- Disturbance and Detection in Power Quality with ClassificationIRJET Journal
This document discusses a hybrid method for classifying power quality disturbances using wavelet transform and fuzzy logic. Various power quality disturbances like sag, swell, and interruption are generated and decomposed using wavelet transform. Features like energy and total harmonic distortion are extracted and fed into a fuzzy expert system for classification of disturbances. A wavelet-based denoising method is also proposed to remove noise before feature extraction, since noise can reduce classification accuracy. The fuzzy expert system uses if-then rules and linguistic variables to classify disturbances based on the extracted features. This hybrid method provides an effective way to detect, classify, and analyze power quality disturbances.
This document discusses applications of artificial intelligence techniques like neural networks, expert systems, and fuzzy logic to power system protection. It provides examples of using these techniques for transmission line fault classification, distance relaying, machine winding protection, transformer differential relaying, and transformer fault diagnosis. The applications aim to make protection schemes more adaptive, reliable, and capable of handling changing system conditions. AI techniques can introduce new concepts like integrated, adaptive, and predictive protection to design smarter digital relays.
Troubleshooting Coherent Optical Communication SystemsCPqD
1) The document discusses troubleshooting of coherent optical communication systems. It covers topics such as market trends driving higher data rates, challenges in coherent measurements, and typical tests and impairments in coherent transmission systems.
2) The document outlines techniques used to maximize transmission capacity within the physical layer, including higher order modulation formats, time-domain pulse shaping, and polarization division multiplexing. It also discusses requirements for test instruments to test these advanced modulation schemes.
3) The presentation provides an overview of using arbitrary waveform generators to emulate optical distortions in the electrical domain, allowing for deterministic and precise testing with complex impairments like phase noise and polarization mode dispersion.
This document describes the implementation of a lock-in amplifier using LabVIEW software and a data acquisition board. A lock-in amplifier can measure very small input signals even in the presence of noise much larger than the signal. It works by multiplying the input signal with a reference signal and then filtering out signals at all frequencies other than the reference frequency. The implemented lock-in amplifier uses a National Instruments DAQ card and pre-amplifier to digitize and process signals on a computer running LabVIEW. It is shown to be effective at measuring low-level signals and analyzing their amplitude and phase characteristics.
These slides present about islanding detection techniques in microgrid systems. Later on the classes other aspects of microgrid protection will be discussed in more detail
Advanced Network Solutions for Electric Power Applicationchowfei
- The document discusses advanced communication networks for electric power applications, focusing on protocols like DNP3 and IEC 61850. It provides an overview of these protocols, their usage in different countries, and how IEC 61850 is emerging as an object-oriented, Ethernet-based standard.
- Case studies are presented that demonstrate applications of Loop Telecom's solutions for various power utility communication networks around the world, including microwave, optical fiber, and wireless technologies.
- Key components discussed include modems, multiplexers, routers, switches, and other devices that support protocols like DNP3, IEC 60870-5, and IEC 61850 over a variety of connection types.
This document summarizes a study comparing the results of Discrete Wavelet Transformation (DWT) analysis using Matlab and VHDL for power systems applications. DWT is proposed to detect minor faults in power transformer windings due to its time-frequency localization properties. The authors implement a DWT architecture in VHDL and compare the wavelet coefficients obtained to theoretical results from Matlab. They find the VHDL results meet the accuracy of the Matlab estimates. The digital implementation of DWT using VHDL allows for more efficient estimation and faster response times compared to traditional methods, improving power quality analysis.
This document provides information about MobileComm Technologies' drive test process for UMTS networks. It includes documentation on tools used for tuning and optimization, parameters measured, call flows, key performance indicators, examples of coverage and interference issues identified, and tips for network tuning. The document contains 47 slides covering topics like coverage verification using P-CPICH measurements, identifying interference and overshooting issues, analyzing call drops, tuning for voice and data calls, and comparing mechanical vs electrical antenna tilts.
Digital Implementation of Costas Loop with Carrier RecoveryIJERD Editor
Demodulator circuit is a basic building block of wireless communication. Digital implementation of
demodulator is attracting more attention for the significant advantages of digital systems than analog systems.
The carrier signal extraction is the main problem in synchronous demodulation in design of demodulator based
on Software Defined Radio. When transmitter or receiver in motion, it is difficult for demodulator to generate
carrier signal same in frequency and phase as transmitter carrier signal due to Doppler shift and Doppler rate.
Here the digital implementation of Costas loop for QPSK demodulation in continuous mode is discussed with
carrier recovery using phase locked loop.
The presentation discusses an islanding detection approach using discrete wavelet transform (DWT) to minimize non-detection zones. DWT is used to extract features from voltage and current signals that can help detect islanding events. Simulation results show the proposed hybrid method, combining DWT feature extraction and communication, improves accuracy and reliability of detection. Future work may explore integrating smart grid technologies, machine learning approaches for feature extraction, and addressing cybersecurity challenges to further advance islanding detection capabilities.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
The document describes experiments performed on time division multiplexing, pulse code modulation, differential pulse code modulation, delta modulation, frequency shift keying, and differential phase shift keying. The experiments aim to study the principles and characteristics of these digital communication techniques by using equipment like multiplexing/demultiplexing trainer kits, PCM modulator and demodulator kits, and oscilloscopes. The procedures involve applying input signals, observing the output waveforms on oscilloscopes, and analyzing the effects of varying signal parameters.
This document provides information about 3G drive testing, including:
1. It describes the steps involved in 3G drive testing and the tools used like software, hardware, and data analysis tools.
2. It explains various 3G network parameters that are analyzed during drive testing like serving cells, active set, neighbors, radio parameters, handovers and more.
3. It includes examples of issues found during drive testing like missing neighbors, poor coverage, and pilot pollution and provides recommendations to address them.
This document discusses using a vector network analyzer (VNA) for signal integrity testing. It begins with an overview of RF connectors and their impact on measurement accuracy. It then describes how a VNA works, measuring both amplitude and phase to determine S-parameters. Key aspects covered include calibration to define a reference plane, measuring transmission and reflection parameters, and converting frequency domain data to the time domain. Applications discussed include time domain reflectometry for fault detection and measuring rise times.
“Head of real time and back office systems in operation”IMDEA Energia
The document discusses smart grids from the perspective of distribution networks. It begins with an introduction and overview of smart grids. It then discusses the current state of distribution networks and energy sources. Next, it outlines a proposed roadmap for smart grids with five stages: 1) advanced metering infrastructure, 2) distributed generation integration, 3) advanced demand management, 4) optimization and coordination of the overall system, and 5) tiempo gestión inteligente de la red. It also discusses ancillary services and the potential role of distributed energy resources. Finally, it concludes that smart grids could provide benefits like increased efficiency, reliability, security of supply, and flexibility through technologies like smart metering, monitoring, and demand response.
This document describes a digital down converter (DDC) implemented on a Xilinx FPGA Virtex-5 device. The DDC allows a received intermediate frequency (IF) signal to be down converted to baseband. It uses a direct digital synthesizer to generate sine and cosine signals to mix with the input samples in a mixer, producing in-phase and quadrature signals. These pass through a low-pass filter to reject images and yield a complex baseband representation of the original signal. Implementing the filter as a multi-stage FIR filter approach optimizes the DDC with respect to hardware complexity, speed and power dissipation compared to a single-stage FIR filter. The DDC is controlled by commands received over
7SR220 series relays include for directional control of the overcurrent and earth fault functionality and are typically installed where fault current can flow in either direction i.e. on interconnected systems. Relays have five current and four voltage inputs they are housed in E6 or E8 cases.
Design, Development and Simulation of Front End Electronics for Nuclear Detec...ijtsrd
Design, Development and Simulation of Front end Electronics for nuclear detectors Preamplifier Amplifier Shaper Discriminator has been presented in this article. The Nuclear Detector Signal Channel NDSC comprises of charge sensitive preamplifier, single stage gain amplifier, CR RC shaping amplifier and integral discriminator. The charge sensitive preamplifier feedback circuit has 1M resistor and 10 pF capacitor that gives its decay time constant t of 10 µs. The gain of amplifier used in this channel is 51. Shaping amplifier which is the combination of high pass and low pass filter with equal time constant t1=t2=t of 5 µs to increase the signal to noise ratio. Single ended or integral discriminator function is to eliminate the system noise and pulse height discrimination. The NDSC has been designed and verified in Proteus 7.7 simulation platform. And the simulation results have been presented to show the performance and characteristics of the channel. M. N. Islam | M. S. Alam | S. Sultana | H. Akhter | M. A. S. Haque "Design, Development and Simulation of Front-End Electronics for Nuclear Detectors: Preamplifier-Amplifier-Shaper-Discriminator" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-6 | Issue-7 , December 2022, URL: https://www.ijtsrd.com/papers/ijtsrd52588.pdf Paper URL: https://www.ijtsrd.com/engineering/electronics-and-communication-engineering/52588/design-development-and-simulation-of-frontend-electronics-for-nuclear-detectors-preamplifieramplifiershaperdiscriminator/m-n-islam
Design, Development and Simulation of Front End Electronics for Nuclear Detec...
PPT_Final_Presentation
1. Detection and Classification
of Disturbances in a Hybrid
Distributed System Using
Wavelet Transform and ANN
GUIDE : Prof. P. R. Subadhra
By,
Sleeba Paul Puthenpurakel
2. Introduction
Rapid Increment in Energy Demand
India : By 2030, Demand = 6 x Current Demand
Feasibility of Renewable Energy Sources
Minimizes the environmental pollution
Advancement in Power Electronics, Internet of Things and Automation
7. Islanding Detection Methods
Communication Based
Communication between DG and Utility
Heavily relies on communication system
Reliable but complex and costly
Active
Perturb System Variables ( Voltage and Frequency)
Small Non - Detection Zone
8. Islanding Detection Methods
Passive
Measures system variables ( Voltage and Frequency )
No Power Quality Issues
Large non - detection zone
Selecting right variables is crucial
Threshold fixing is difficult
9. Computational Intelligence based methods
Mimics human intelligence
Solves non - linear multi objective problems
High speed and accuracy
Learn from examples
Training of algorithm is a one time process
Can detect and classify disturbances
10. Motivation of Thesis
Importance of Distributed Generation
Unintentional Islanding hazards
Inabilities of conventional methods
Power Quality issues
High Non – Detection zone
Cost of implementation
Popularity and Robustness of Computational Intelligence and Machine
learning
11. Objectives
Disturbance Detection using a conventional method in Hybrid System
Disturbance Detection using Wavelet Transform in Hybrid System
Disturbance Classification using Computational Intelligence Method
Comparative study
13. Hybrid System Specifications
PV System
Rated Power - 250 kW
Irradiance - 1000 W/m2
Wind Power Plant
Rated Power - 1.5 MW
Wind Speed - 12 m/s
Grid
14. Conventional Islanding Detection Method
Detection of Harmonics Method
THD
Measure of Harmonic Content in the signal
Based on Fourier Transform
Passive Method
THD of Voltage Signal at PCC is calculated
Normal value of THD at grid connected mode < 5% ( IEEE Standard)
15. Transform of a Signal
Real world signals are time domain ( Time V/s Amplitude )
Transform gives additional information
Frequency domain
Stationary signal
Frequency content dont change with time
All frequencies are present in all time !!
19. Fourier Transform - Anxieties
Gives the overall frequency content information
Frequency and Amplitude
Misses the time domain information
Can’t extract complete information from Non - Stationary signals
Frequency at a particular instant of time can’t be calculated
Can't differentiate events using the variation in frequency content of
20. THD (%) - Hybrid System Connected to Grid
Loading
(MW)
Grid
Connected
Islanding L-G Fault L-L Fault
Non -
Linear Load
Switch
0.875 1.2665 11.1161 3.5811 6.0342 62.3332
1 1.1347 8.0497 3.5966 6.0166 62.2358
1.3 0.953 3.3066 3.7453 5.9751 61.8576
1.75 0.7766 4.1653 3.9311 5.8795 61.3211
● Rated Power - 1.75 kW ( 0.25 MW + 1.5 MW )
● Loading varies from 50 % to 100 % of rated power
21. Inferences
THD can detect Islanding as well as Power Quality Issues
THD on Islanding event changes abruptly with load change
THD fails to maintain a threshold for Islanding
THD fails to differentiate Islanding and Power Quality Issues
23. Introduction to Wavelet Transform
Fourier Transform
Apt for Decomposition of Stationary
Signals
Basis function is Sine wave
Signal is represented as translated
and dilated versions of Sine
Wave
Frequency domain information is
available
Wavelet Transform
Apt for Decomposition of Non -
Stationary Signals
Basis function is Wavelet
Signal is represented as translated
and dilated versions of
Wavelet
Frequency and Time domain
information is available
24. Advanced Multirate Signal Processing
Non Stationary Signal
High Frequency Parts
Low Frequency Parts
High Frequency parts
Quick parts
Need more samples to detect them
Low Frequency parts
25. Discrete Wavelet Transform
v - Input Signal
Ψ - Mother Wavelet
- Translation Constant / Position
- Dilation Constant / Scale
Dyadic scale have =
26. Discrete Wavelet Transform - Working
● x[n] → Signal
● h[n] → HPF
● g[n] → LPF
Coefficients
Filters
Down - Sampling
27. Frequency Division
● Let sample frequency of signal = Fs
■ Eg. Fs = 1 kHz
Wavelet Level Frequency Band (Hz)
Level 1 500 - 1000
Level 2 250 - 500
Level 3 125 - 250
Level 4 62.5 - 125
28. Mother Wavelet Selection
Reconstruction capability
Empirically find if the input signal can be reconstructed by the wavelet perfectly
Similarity of Wavelet and Input Signal
29. Daubechies 4 Mother Wavelet
● Disturbance in power system features exhibit sharp changes
● Daubechies mother wavelet with low order
○ Which have an angular shape
○ Ideal to analyse sharp changes
■ For smooth features , a higher order is preferred.
31. Statistical Indices Of Wavelet Transform
At a particular frequency band / level
Standard Deviation
Power of signal when its mean =0
L2 Norm ( Energy )
32. Wavelet Transform Based Approach
Extract Neg.
Sequence Voltage
from PCC
Perform Wavelet
Transform
Find SD and Energy
values of appropriate
levels
Fix the threshold
GRID CONNECTED MODE - UNDISTURBED SYSTEM
33. Wavelet Transform Based Approach
Extract Neg.
Sequence Voltage
from PCC
Perform Wavelet
Transform
Find SD and Energy
values of appropriate
levels
Detect Disturbance
by Comparing With
Threshold
SYSTEM UNDER DISTURBANCE
34. Frequency Levels Under Consideration
Negative Sequence Voltage taken from PCC
Sample Frequency taken - 1 kHz , Fundamental Frequency - 60 Hz
Wavelet Level Frequency Band (Hz)
Level 1 500 - 1000
Level 2 250 - 500
Level 3 125 - 250
Level 4 62.5 - 125
Level 5 31.25 - 62.5
35. SD3 - Hybrid System Connected to Grid
● Standard Deviation at level n - SDn
Loading
(MW)
Grid
Connected
Islanding L-G Fault L-L Fault
Non -
Linear Load
Switch
0.875 0.00011473 0.03401753 0.00494453 0.00911728 0.01280362
1 0.00011594 0.03204665 0.00494597 0.00911516 0.01280433
1.3 0.00010763 0.02510713 0.00495142 0.00911595 0.01279189
1.75 0.00012745 0.00583276 0.00495896 0.00912749 0.01277151
36. SD4 - Hybrid System Connected to Grid
● Standard Deviation at level n - SDn
Loading
(MW)
Grid
Connected
Islanding L-G Fault L-L Fault
Non -
Linear Load
Switch
0.875 0.00014444 0.03705120 0.01195818 0.02928778 0.02509573
1 0.00015432 0.04406543 0.01196308 0.02921008 0.02509539
1.3 0.00017652 0.02957596 0.01204052 0.02910395 0.02506549
1.75 0.00022712 0.00608325 0.01213379 0.02892913 0.02500862
37. E3 - Hybrid System Connected to Grid
● Energy at level n - En
Loading
(MW)
Grid
Connected
Islanding L-G Fault L-L Fault
Non -
Linear Load
Switch
0.875 0.00130841 0.39045041 0.05639256 0.10401861 0.14671166
1 0.00132418 0.36693973 0.05641079 0.10399256 0.14673016
1.3 0.00123171 0.29207070 0.05647472 0.10399785 0.14659020
1.75 0.00145480 0.06664993 0.05656272 0.10413084 0.14638457
38. E4 - Hybrid System Connected to Grid
● Energy at level n - En
Loading
(MW)
Grid
Connected
Islanding L-G Fault L-L Fault
Non -
Linear Load
Switch
0.875 0.00119563 0.30587180 0.09861007 0.24154712 0.20694654
1 0.00128137 0.36386052 0.09865040 0.24090679 0.20694387
1.3 0.00146062 0.24395503 0.09928896 0.24003145 0.20669716
1.75 0.00187444 0.05016677 0.10005795 0.23858983 0.20622875
39. Inferences
Change in SD and Energy are not abrupt, unlike THD
Thus it's easy to fix a threshold with SD and Energy
SD and Energy can classify the events
Between Islanding and Power Quality Issues
40. Machine Learning
Subfield of Computer Science
Study of pattern recognition
Learns from examples
Training → Learning → Prediction
Category
41. Applications
Voice assistants like Google Voice Search , Cortana and Siri
Product Recommendations on E- Commerce sites
Spam mail classifier
According to Gartner’s Hype Cycle 2015
Most promising technology of future
43. Input Vector ( Feature Vector )
● Loading of DG (MW)
● Standard Deviation at Level 4
● Standard Deviation at Level 3
● Energy at level 4
● Energy at level 3
51. Data Set
No. of examples for each event - 26
No. of events = 5
Total Examples = 26 x 5 = 130
Splitting percentage of data - 70 %
Training Set - 91
52. Inferences
Verified using 3-fold cross validation
ANN can classify and identify the events with excellent accuracy
Prediction accuracy is > 95 %
53. Final Conclusions
WT Indices provide a better prospect on detecting and classifying Islanding
and PQ disturbances in a Hybrid DG System
THD fails to perform accurate classification
Implementation using Machine Learning Classifier
High prediction accuracy
54. Future Scope
Detection of Voltage Swell events are not well performed by WT
Load Switching
Capacitor Bank switching
Performance of WT at noisy environments
Feature Vector Selection
55. Implementation
Implementation as a Web Service
Using Microsoft Azure Machine Learning Suite
API Key -
zogVJpUKUmTEEh3auMuVYZ1q1tBKBWA+tHeZWIyzuG2sYUfxHKJ7F4IpXhGALe5IiVpunz
MHjDF8i0gTImfqfA==
URL -
https://ussouthcentral.services.azureml.net/workspaces/8e3a01b9b5a94cd8be8f69c85b
fd1215/services/923ca965d52a46788d91c32cd9cdc9fd/execute?api-
version=2.0&details=true
59. Reference
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61. Publications [1] Sleeba Paul Puthenpurakel, Subadhra P.R.,
“Islanding Detection in Grid-Connected 100 KW
Photovoltaic System Using Wavelet Transform”,
International Conference on Emerging Trends in
Smart Grid Technology - INCETS'16, IJIRSET Volume
5, Special Issue 5, April 2016
[2] Sleeba Paul Puthenpurakel, Subadhra P.R.,
“Identification and Classification of Microgrid
Disturbances in a Hybrid Distributed Generation
System Using Wavelet Transform”, International
Conference on Next Generation Intelligent Systems”