Nuwan Perera - Academia.edu (original) (raw)

Papers by Nuwan Perera

Research paper thumbnail of High-Throughput Evaluation of Metabolic Activities Using Reverse Phase Protein Array Technology

Neuron Signaling in Metabolic Regulation

Research paper thumbnail of Patients with Lung Cancer of Different Racial Backgrounds Harbor Distinct Immune Cell Profiles

Cancer Research Communications

Tumors accumulated with infiltrated immune cells (hot tumors) have a higher response rate to immu... more Tumors accumulated with infiltrated immune cells (hot tumors) have a higher response rate to immune checkpoint blockade, when compared with those with minimal T-cell infiltration (cold tumors). We report here that patients with lung cancer with different racial backgrounds harbored distinct immune cell profiles in the tumor microenvironment. Compared with African Americans (AA), Caucasian Americans (CA) exhibited increased immune cell infiltration and vasculature, and increased survival. Changes of survival and immune profile were most pronounced among active smokers and nonsmokers, compared with former smokers and total patients. Neighborhood analysis showed that immune cells accumulated around cancer cells in CAs but not AAs. Our findings reveal intrinsic biological differences between AA and CA patients with lung cancer, suggesting that treatment plans should be tailored for patients with different racial backgrounds. Significance: We report biological racial differences among pa...

Research paper thumbnail of Directional Protection Applied to Wind Systems: Challenges and Solutions

2019 72nd Conference for Protective Relay Engineers (CPRE)

This paper investigates the applicability of a flexible directional element applied to a distance... more This paper investigates the applicability of a flexible directional element applied to a distance protection scheme with windfarms. The directional element investigated in this study operates based on sequence components of voltage and current measurements. This directional element provides the flexibility for users to enable/disable sequence elements and change their sensitivity levels depending on the application requirements. In addition, it provides extra security during subharmonic conditions. Some case studies are presented covering various applications such as series compensated systems and passive inverter based generating system.

Research paper thumbnail of Agent-based protection scheme for distribution networks with distributed generators

2006 IEEE Power Engineering Society General Meeting

This paper describes a novel protection scheme for a distribution network with distributed genera... more This paper describes a novel protection scheme for a distribution network with distributed generators. The network is divided into several segments to facilitate fault isolation. Relay agents protecting the system are installed at points of interconnection between different network segments. These relay agents communicate with the neighboring agents through an asynchronous communication network. A wavelet transform coefficients based technique is

Research paper thumbnail of sj-pdf-2-asp-10.1177_00037028211057574 – Supplemental Material for Transmission Infrared Microscopy and Machine Learning Applied to the Forensic Examination of Original Automotive Paint

Supplemental Material, sj-pdf-2-asp-10.1177_00037028211057574 for Transmission Infrared Microscop... more Supplemental Material, sj-pdf-2-asp-10.1177_00037028211057574 for Transmission Infrared Microscopy and Machine Learning Applied to the Forensic Examination of Original Automotive PaintFrancis by Francis Kwofie, Nuwan Undugodage D. Perera, Kaushalya S. Dahal, George P. Affadu-Danful, Koichi Nishikida, and Barry K. Lavine in Applied Spectroscopy

Research paper thumbnail of sj-pdf-3-asp-10.1177_00037028211057574 – Supplemental Material for Transmission Infrared Microscopy and Machine Learning Applied to the Forensic Examination of Original Automotive Paint

Supplemental Material, sj-pdf-3-asp-10.1177_00037028211057574 for Transmission Infrared Microscop... more Supplemental Material, sj-pdf-3-asp-10.1177_00037028211057574 for Transmission Infrared Microscopy and Machine Learning Applied to the Forensic Examination of Original Automotive PaintFrancis by Francis Kwofie, Nuwan Undugodage D. Perera, Kaushalya S. Dahal, George P. Affadu-Danful, Koichi Nishikida, and Barry K. Lavine in Applied Spectroscopy

Research paper thumbnail of A machine learning application for form-finding of tensegrity structures

Research paper thumbnail of Kinase-Catalyzed Labeling To Study Phosphatase Substrates, Phosphosite-Specific Kinases, And Histidine Kinases

Kinases and phosphatases are the key enzymes governing protein phosphorylation, which plays a maj... more Kinases and phosphatases are the key enzymes governing protein phosphorylation, which plays a major role in cell signaling. Unregulated cell signaling can cause diseases, such as cancer. Therefore, characterizing the function of kinase and phosphatase activities in cell signaling is vital. Unfortunately, limited methods are available to identify kinase and phosphatase substrates. To address this need, the Pflum lab developed a series of methods based on the ability of kinases to accept ɤ- phosphoryl modified ATP analogs as a cosubstrate to label cellular protein. Related to phosphatases, K-BIPS (Kinase-catalyzed Biotinylation to Identify Phosphatase Substrates) was tested to identify substrates of tyrosine phosphatase PTP1B by combining ATP-biotin and RNA interference-mediated phosphatase inactivation. From the mass spectrometry analysis, eight high confident possible protein hits were identified including PKM (pyruvate kinase PK – a known substrate of PTP1B) strengthening the K-BIPS as a working method. LDHA also was validated as a new substrate of PTP1B. As a second application of kinase catalyzed labeling, K-CLASP (Kinase Catalyzed CrossLinking And Streptavidin Purification) was applied to identify the kinases of the CARP-1, HDAC1 and MrpC proteins using ATP-arylazide for collaboration projects. The K-CLASP method was able to identify kinases and associated proteins for CARP-1 and HDAC1, proving that K-CLASP is a valuable tool to identify kinases in known phosphosite. Interestingly, several uncharacterized proteins and bifunctional enzyme were identified for MrpC in Myxococcus xanthus lysate. As a third and final application of ATP analogs, ATP-biotin was tested to label human histidine kinases (NME1 and NME2), which confirmed that both kinases are successfully biotinylated. In summary, kinase-catalyzed labeling methods are empowering tools to characterize cell signaling events of kinases, phosphatases, and their substrates

Research paper thumbnail of Power system transient classification for protection relaying

2008 13th International Conference on Harmonics and Quality of Power, 2008

ABSTRACT This paper investigates the applicability of decision tree based classifiers and hidden ... more ABSTRACT This paper investigates the applicability of decision tree based classifiers and hidden Markov model based classifiers to distinguish the transients originating from the faults from the transients due to normal switching events. Current signals due to different types of events such as faults, load switching, and capacitor bank switching were generated using a high voltage transmission system simulated in PSCAD/EMTDC simulation software. Simulated transients were used to train and test the classifiers. The feature vectors for the investigated techniques.

Research paper thumbnail of Power grid stability protection against GIC using a capacitive grounding circuit

PES T&D 2012, 2012

ABSTRACT This paper investigates a method to minimize the flow of geo-magnetically induced curren... more ABSTRACT This paper investigates a method to minimize the flow of geo-magnetically induced currents (GIC) through power transformers. The solution examined was an AC grounding path provided by a capacitor between the earth ground and the neutral point of a power transformer only when GIC was detected. The effectiveness and problems of this approach were investigated through simulation of a 765 kV transmission system in an electromagnetic transient (EMT) simulation program.

Research paper thumbnail of Micro processor based advanced bus protection scheme using IEC 61850 process bus (9-2) sampled values

2017 70th Annual Conference for Protective Relay Engineers (CPRE), 2017

A novel, phase segregated bus differential protection scheme, which utilizes independent multipri... more A novel, phase segregated bus differential protection scheme, which utilizes independent multiprinciple advanced protection algorithms, such as, differential percent slope, delta phase directional comparison, rate of change of differential (ROCOD) currents, delta phase directional comparison on zero sequence current differential, fast CT saturation detection, second harmonic blocking and a check zone to secure the electrical bus bars upto three zones (two main and one transfer bus) will be discussed. Various combinations of the bus architectures or topologies can be protected with bus couplers, isolators, and CTs configurations including the end-faults detection capability. The proposed advanced microprocessor based bus protection scheme does not require digital current inputs (sampled values) from Merging Units; instead, it has the ability to measure the conventional CT currents within the protection unit, and will share / distribute the sampled values using IEC 61850, 9-2 protocol, as a Merging Unit with other protection units to perform the overall differential protection. Each protection unit therefore acts as a processing (subscribing sampled values) and as well as a Merging Unit (publishing sampled values). The scheme can be scaled to support up to 24 bays (24 sets of three phase CT current inputs) and a three phase PT voltage input with 4 individual relay protection unit (6 sets of three phase CT current Inputs per relay) functions together as one protection scheme, in a very compact electrical panel (4 x 3U rack units). For time synchronization, additional inputs, and outputs, an I/O unit is used to accommodate the breaker status, isolator status, and any other inputs into the bus protection scheme.

Research paper thumbnail of Visible Light Communication by Using LED Array for Automatic Wheelchair Control in Hospitals

2019 IEEE 23rd International Symposium on Consumer Technologies (ISCT), 2019

In Japan, there is a shortage of caretakers due to the increase of aging population. As a solutio... more In Japan, there is a shortage of caretakers due to the increase of aging population. As a solution for this issue, an automated wheelchair driving system is proposed for the hospitals to reduce the workload of caretakers. In this system, the communication between the wheelchair and the external environment is realized by visible light communication which has no negative influence on the human body like other wave based communication methods. An LED matrix and a camera are used to achieve this communication. The wheelchair is guided by an LED blinking pattern which is recognized by a camera installed in the wheelchair. In this paper, the communication side of the system is studied. A set of experiments were carried out to validate the proposed system and their results emphasize the effectiveness of the system.

Research paper thumbnail of Transmission Infrared Microscopy and Machine Learning Applied to the Forensic Examination of Original Automotive Paint

Applied Spectroscopy, 2021

Alternate least squares (ALS) reconstructions of the infrared (IR) spectra of the individual laye... more Alternate least squares (ALS) reconstructions of the infrared (IR) spectra of the individual layers from original automotive paint were analyzed using machine learning methods to improve both the accuracy and speed of a forensic automotive paint examination. Twenty-six original equipment manufacturer (OEM) paints from vehicles sold in North America between 2000 and 2006 served as a test bed to validate the ALS procedure developed in a previous study for the spectral reconstruction of each layer from IR line maps of cross-sectioned OEM paint samples. An examination of the IR spectra from an in-house library (collected with a high-pressure transmission diamond cell) and the ALS reconstructed IR spectra of the same paint samples (obtained at ambient pressure using an IR transmission microscope equipped with a BaF2 cell) showed large peak shifts (approximately 10 cm−1) with some vibrational modes in many samples comprising the cohort. These peak shifts are attributed to differences in t...

Research paper thumbnail of Commissioning process and acceptance test of a sub-harmonic protection relay

2017 70th Annual Conference for Protective Relay Engineers (CPRE), 2017

Numerous technical papers have been published discussing the topic of Sub-Synchronous Resonance (... more Numerous technical papers have been published discussing the topic of Sub-Synchronous Resonance (SSR) and more recently about new protection devices capable of detecting and protecting against the detrimental effects of SSR. The advent of such protection devices has created the new challenge of testing and commissioning such devices. Commissioning sub-harmonic protection devices require following a process that differs from the traditional testing and commissioning process of microprocessor devices. This paper presents the experiences of the authors during the commissioning of Sub-harmonic Protection Relays and describes the process that was followed prior to the site visit and then during the actual commissioning of the relay. The paper will review the following topics: • The characteristics of a Sub-Harmonic Protection Relay • The engineering process for the determination of settings • The determination of test cases to make sure all the features of the relay are properly tested • The use of a real time digital simulator for the preparation of COMTRADE files to be used during the relay testing • The process followed at site to commission the relay by using advanced relay test equipment capable of playing back COMTRADE files. During the commissioning process of sub-harmonic protection relays the authors discovered that there is very little understanding on SSR and SSCI phenomena, on the engineering behind the selection of settings for sub-harmonic protection IEDs and on the process of testing and commissioning such IEDs, hence the need to educate the Protection & Control community. The paper describes the use of software capable of simulating and modeling power systems, similar to PSCAD™/EMTDC™ or RTDS TM for the creation of test cases in COMTRADE format that will be used to test de relay. Prior to the creation of test cases, the process requires the review of power system simulation cases that were used to determine the relay settings in order to create COMTRADE test cases that will confirm that the relay responds as expected. The process requires testing for: • Sub-harmonic frequency ranges-making sure the relay does not misoperate for frequencies outside the desire frequency range • Sub-harmonic magnitudes-making sure the relay does not misoperate for sub-harmonics with magnitudes below the set thresholds • Protection features at the fundamental frequency

Research paper thumbnail of Application of infrared microscopy and alternating least squares to the forensic analysis of automotive paint chips

Journal of Chemometrics, 2020

To collect infrared (IR) absorbance spectra from an automotive paint chip with an IR imaging micr... more To collect infrared (IR) absorbance spectra from an automotive paint chip with an IR imaging microscope, it is a common practice to cast the paint chip in epoxy and then cross section it using a microtome to reveal the individual layers of paint. Ideally, the epoxy should present little or no spectral interference. However, the epoxy can infiltrate individual layers of the paint chip as it cures contaminating the IR spectra of the layers and impairing the accuracy of a search of each of these layers against an automotive paint library. In this study, we have demonstrated that automotive paint chips can be successfully cross sectioned without the use of embedding media. Sample preparation is easier, and more importantly, interfering peaks in the spectra due to the epoxy are eliminated. To demonstrate the advantages of this approach for sample preparation, IR image maps of four automotive paint chips that were not cast in epoxy prior to cross sectioning were collected. After each IR image was unfolded using an oblique transit to traverse the image, the spectra of the individual paint layers comprising the line map were reconstructed by alternating least squares. Comparing each recovered IR spectrum against a spectral library, we show that high quality spectral matches were obtained for spectra from the same line/model of the vehicle from which the paint sample originated. When the same paint chips were cast in epoxy prior to cross sectioning, high quality spectral matches could not always be obtained. K E Y W O R D S chemometrics, cross sectioning, forensic automotive paint analysis, microtome, multivariate curve resolution, spectral library matching, transmission infrared imaging microscopy 1 | INTRODUCTION Automotive paint is an important category of trace evidence as it can provide crucial links in the early phase of an investigation or evidence of association in a criminal proceeding. Automotive paint in the form of a chip is often the only evidence recovered at the crime-scene of a vehicle related fatality such as a hit-and-run where injury or death to a pedestrian has occurred. Studies 1,2 conducted by the Royal Canadian Mounted Police (RCMP) almost 45 years ago showed that automotive vehicles could be discriminated by directly comparing the color, layer sequence, and chemical composition of each individual layer in an original equipment manufacturer (OEM) paint system. To make these

Research paper thumbnail of Series Compensated Transmission Line Protection Using Pscad

International Journal of Advance Engineering and Research Development, 2017

In order to meet the high demand for power transmission capacity, some power companies have insta... more In order to meet the high demand for power transmission capacity, some power companies have installed series capacitor on power transmission line. The introduction of the capacitance in series with the line reactance allows reduction in line impedance, thus resulting increased power transmission capability. It provides the benefits of increased system capacity, reduced system losses and voltage regulation. The paper presents series compensated transmission line model by using PSCAD. Results are tested with different fault locations for compensated and without compensated transmission line. Performance of the developed method ensures that the proposed scheme gives the apparent effects when compensation is going to be added in the line.

Research paper thumbnail of Performance Evaluation of an Enhanced Bus Differential Protection Relay

2019 72nd Conference for Protective Relay Engineers (CPRE), 2019

The busbar protection relays typically implements low impedance percentage differential principle... more The busbar protection relays typically implements low impedance percentage differential principle using dual slope characteristics. These relays may sometimes misoperate in response to the CT saturation during close-in external faults, and the subsidence current present after clearing external faults. A primary reason for such misoperations is the fact that the traditional percentage differential principle relies exclusively on current magnitudes rather than directionality for tripping decisions. This paper evaluates the performance of an enhanced bus differential relay which uses different principles that distinguish between external and internal faults so as to enhance the security of differential protection. Extensive testing has been carried out to evaluate the effectiveness of the new principles in enhancing the security for external faults.

Research paper thumbnail of Solutions for Monitoring GIC Events Using a Digital Fault Recording System

The GMD (Geo Magnetic Disturbance) activity, which causes GIC (Geomagnetic Induced Current) and i... more The GMD (Geo Magnetic Disturbance) activity, which causes GIC (Geomagnetic Induced Current) and its impact, has been seriously looked into in many geographical areas across the globe. Specifically, the North American continent has more probability of impact with GIC as per the calculations and as well as the events that have happened in the past. It is clear that the GIC phenomenon causes widespread effects throughout the electrical grid. The electric field gradient and the induced current can flow over wide areas of power systems. This includes the entire possible closed electric circuit path between grounded points. This technical paper provides general information on GIC in power systems and describes the causes and sources of GIC and touch on the consequences on power transformers. In addition, it provides information on how to apply a power system monitoring device to monitor for the negative effect of GIC on power transformers.

Research paper thumbnail of Spectrophotometric Analysis of Food Colorants

Coloring agents or food dyes have been used to make food more attractive since ancient times. The... more Coloring agents or food dyes have been used to make food more attractive since ancient times. The detection and quantification of dyes in food samples remain a challenge for food scientists because present methods involve the use of expensive chromatographic separation techniques, such as the high-performance liquid chromatograph (HPLC). Alternatively, spectrophotometers are faster and less expensive than HPLC. Utilizing spectrophotometric methods would increase the efficiency of food safety assessments. In this article, we review the benefits and limitations of spectrophotometric methods which provide a promising tool for the direct quantification of dyes in food matrices.

Research paper thumbnail of Applicability of Synchrophasor Based Frequency Data for Protection and Control Applications

2019 72nd Conference for Protective Relay Engineers (CPRE), 2019

Synchrophasor based wide area monitoring, protection, and control applications are widely used al... more Synchrophasor based wide area monitoring, protection, and control applications are widely used all over the world. The latest IEEE synchro-phasor standard C37.118.1a-2014 provides necessary steady-state and dynamic performance requirements for two different application categories namely the "Protection (P) Class" and the "Metering (M) Class" [1-2]. Satisfactions of these application classes require inclusion of digital filters into the standard phasor calculations. Although the IEEE standard provides benchmark test cases for dynamic and steady state frequency measurements, from application point of view, it is essential to understand their applicability for various protection and control applications specified by authorities and standards such as NERC, BAL-0003-1. The information discussed in this paper is useful for users to understand the impact of the performance filters introduced in the latest synchro-phasor standard applicable for frequency related power system applications.

Research paper thumbnail of High-Throughput Evaluation of Metabolic Activities Using Reverse Phase Protein Array Technology

Neuron Signaling in Metabolic Regulation

Research paper thumbnail of Patients with Lung Cancer of Different Racial Backgrounds Harbor Distinct Immune Cell Profiles

Cancer Research Communications

Tumors accumulated with infiltrated immune cells (hot tumors) have a higher response rate to immu... more Tumors accumulated with infiltrated immune cells (hot tumors) have a higher response rate to immune checkpoint blockade, when compared with those with minimal T-cell infiltration (cold tumors). We report here that patients with lung cancer with different racial backgrounds harbored distinct immune cell profiles in the tumor microenvironment. Compared with African Americans (AA), Caucasian Americans (CA) exhibited increased immune cell infiltration and vasculature, and increased survival. Changes of survival and immune profile were most pronounced among active smokers and nonsmokers, compared with former smokers and total patients. Neighborhood analysis showed that immune cells accumulated around cancer cells in CAs but not AAs. Our findings reveal intrinsic biological differences between AA and CA patients with lung cancer, suggesting that treatment plans should be tailored for patients with different racial backgrounds. Significance: We report biological racial differences among pa...

Research paper thumbnail of Directional Protection Applied to Wind Systems: Challenges and Solutions

2019 72nd Conference for Protective Relay Engineers (CPRE)

This paper investigates the applicability of a flexible directional element applied to a distance... more This paper investigates the applicability of a flexible directional element applied to a distance protection scheme with windfarms. The directional element investigated in this study operates based on sequence components of voltage and current measurements. This directional element provides the flexibility for users to enable/disable sequence elements and change their sensitivity levels depending on the application requirements. In addition, it provides extra security during subharmonic conditions. Some case studies are presented covering various applications such as series compensated systems and passive inverter based generating system.

Research paper thumbnail of Agent-based protection scheme for distribution networks with distributed generators

2006 IEEE Power Engineering Society General Meeting

This paper describes a novel protection scheme for a distribution network with distributed genera... more This paper describes a novel protection scheme for a distribution network with distributed generators. The network is divided into several segments to facilitate fault isolation. Relay agents protecting the system are installed at points of interconnection between different network segments. These relay agents communicate with the neighboring agents through an asynchronous communication network. A wavelet transform coefficients based technique is

Research paper thumbnail of sj-pdf-2-asp-10.1177_00037028211057574 – Supplemental Material for Transmission Infrared Microscopy and Machine Learning Applied to the Forensic Examination of Original Automotive Paint

Supplemental Material, sj-pdf-2-asp-10.1177_00037028211057574 for Transmission Infrared Microscop... more Supplemental Material, sj-pdf-2-asp-10.1177_00037028211057574 for Transmission Infrared Microscopy and Machine Learning Applied to the Forensic Examination of Original Automotive PaintFrancis by Francis Kwofie, Nuwan Undugodage D. Perera, Kaushalya S. Dahal, George P. Affadu-Danful, Koichi Nishikida, and Barry K. Lavine in Applied Spectroscopy

Research paper thumbnail of sj-pdf-3-asp-10.1177_00037028211057574 – Supplemental Material for Transmission Infrared Microscopy and Machine Learning Applied to the Forensic Examination of Original Automotive Paint

Supplemental Material, sj-pdf-3-asp-10.1177_00037028211057574 for Transmission Infrared Microscop... more Supplemental Material, sj-pdf-3-asp-10.1177_00037028211057574 for Transmission Infrared Microscopy and Machine Learning Applied to the Forensic Examination of Original Automotive PaintFrancis by Francis Kwofie, Nuwan Undugodage D. Perera, Kaushalya S. Dahal, George P. Affadu-Danful, Koichi Nishikida, and Barry K. Lavine in Applied Spectroscopy

Research paper thumbnail of A machine learning application for form-finding of tensegrity structures

Research paper thumbnail of Kinase-Catalyzed Labeling To Study Phosphatase Substrates, Phosphosite-Specific Kinases, And Histidine Kinases

Kinases and phosphatases are the key enzymes governing protein phosphorylation, which plays a maj... more Kinases and phosphatases are the key enzymes governing protein phosphorylation, which plays a major role in cell signaling. Unregulated cell signaling can cause diseases, such as cancer. Therefore, characterizing the function of kinase and phosphatase activities in cell signaling is vital. Unfortunately, limited methods are available to identify kinase and phosphatase substrates. To address this need, the Pflum lab developed a series of methods based on the ability of kinases to accept ɤ- phosphoryl modified ATP analogs as a cosubstrate to label cellular protein. Related to phosphatases, K-BIPS (Kinase-catalyzed Biotinylation to Identify Phosphatase Substrates) was tested to identify substrates of tyrosine phosphatase PTP1B by combining ATP-biotin and RNA interference-mediated phosphatase inactivation. From the mass spectrometry analysis, eight high confident possible protein hits were identified including PKM (pyruvate kinase PK – a known substrate of PTP1B) strengthening the K-BIPS as a working method. LDHA also was validated as a new substrate of PTP1B. As a second application of kinase catalyzed labeling, K-CLASP (Kinase Catalyzed CrossLinking And Streptavidin Purification) was applied to identify the kinases of the CARP-1, HDAC1 and MrpC proteins using ATP-arylazide for collaboration projects. The K-CLASP method was able to identify kinases and associated proteins for CARP-1 and HDAC1, proving that K-CLASP is a valuable tool to identify kinases in known phosphosite. Interestingly, several uncharacterized proteins and bifunctional enzyme were identified for MrpC in Myxococcus xanthus lysate. As a third and final application of ATP analogs, ATP-biotin was tested to label human histidine kinases (NME1 and NME2), which confirmed that both kinases are successfully biotinylated. In summary, kinase-catalyzed labeling methods are empowering tools to characterize cell signaling events of kinases, phosphatases, and their substrates

Research paper thumbnail of Power system transient classification for protection relaying

2008 13th International Conference on Harmonics and Quality of Power, 2008

ABSTRACT This paper investigates the applicability of decision tree based classifiers and hidden ... more ABSTRACT This paper investigates the applicability of decision tree based classifiers and hidden Markov model based classifiers to distinguish the transients originating from the faults from the transients due to normal switching events. Current signals due to different types of events such as faults, load switching, and capacitor bank switching were generated using a high voltage transmission system simulated in PSCAD/EMTDC simulation software. Simulated transients were used to train and test the classifiers. The feature vectors for the investigated techniques.

Research paper thumbnail of Power grid stability protection against GIC using a capacitive grounding circuit

PES T&D 2012, 2012

ABSTRACT This paper investigates a method to minimize the flow of geo-magnetically induced curren... more ABSTRACT This paper investigates a method to minimize the flow of geo-magnetically induced currents (GIC) through power transformers. The solution examined was an AC grounding path provided by a capacitor between the earth ground and the neutral point of a power transformer only when GIC was detected. The effectiveness and problems of this approach were investigated through simulation of a 765 kV transmission system in an electromagnetic transient (EMT) simulation program.

Research paper thumbnail of Micro processor based advanced bus protection scheme using IEC 61850 process bus (9-2) sampled values

2017 70th Annual Conference for Protective Relay Engineers (CPRE), 2017

A novel, phase segregated bus differential protection scheme, which utilizes independent multipri... more A novel, phase segregated bus differential protection scheme, which utilizes independent multiprinciple advanced protection algorithms, such as, differential percent slope, delta phase directional comparison, rate of change of differential (ROCOD) currents, delta phase directional comparison on zero sequence current differential, fast CT saturation detection, second harmonic blocking and a check zone to secure the electrical bus bars upto three zones (two main and one transfer bus) will be discussed. Various combinations of the bus architectures or topologies can be protected with bus couplers, isolators, and CTs configurations including the end-faults detection capability. The proposed advanced microprocessor based bus protection scheme does not require digital current inputs (sampled values) from Merging Units; instead, it has the ability to measure the conventional CT currents within the protection unit, and will share / distribute the sampled values using IEC 61850, 9-2 protocol, as a Merging Unit with other protection units to perform the overall differential protection. Each protection unit therefore acts as a processing (subscribing sampled values) and as well as a Merging Unit (publishing sampled values). The scheme can be scaled to support up to 24 bays (24 sets of three phase CT current inputs) and a three phase PT voltage input with 4 individual relay protection unit (6 sets of three phase CT current Inputs per relay) functions together as one protection scheme, in a very compact electrical panel (4 x 3U rack units). For time synchronization, additional inputs, and outputs, an I/O unit is used to accommodate the breaker status, isolator status, and any other inputs into the bus protection scheme.

Research paper thumbnail of Visible Light Communication by Using LED Array for Automatic Wheelchair Control in Hospitals

2019 IEEE 23rd International Symposium on Consumer Technologies (ISCT), 2019

In Japan, there is a shortage of caretakers due to the increase of aging population. As a solutio... more In Japan, there is a shortage of caretakers due to the increase of aging population. As a solution for this issue, an automated wheelchair driving system is proposed for the hospitals to reduce the workload of caretakers. In this system, the communication between the wheelchair and the external environment is realized by visible light communication which has no negative influence on the human body like other wave based communication methods. An LED matrix and a camera are used to achieve this communication. The wheelchair is guided by an LED blinking pattern which is recognized by a camera installed in the wheelchair. In this paper, the communication side of the system is studied. A set of experiments were carried out to validate the proposed system and their results emphasize the effectiveness of the system.

Research paper thumbnail of Transmission Infrared Microscopy and Machine Learning Applied to the Forensic Examination of Original Automotive Paint

Applied Spectroscopy, 2021

Alternate least squares (ALS) reconstructions of the infrared (IR) spectra of the individual laye... more Alternate least squares (ALS) reconstructions of the infrared (IR) spectra of the individual layers from original automotive paint were analyzed using machine learning methods to improve both the accuracy and speed of a forensic automotive paint examination. Twenty-six original equipment manufacturer (OEM) paints from vehicles sold in North America between 2000 and 2006 served as a test bed to validate the ALS procedure developed in a previous study for the spectral reconstruction of each layer from IR line maps of cross-sectioned OEM paint samples. An examination of the IR spectra from an in-house library (collected with a high-pressure transmission diamond cell) and the ALS reconstructed IR spectra of the same paint samples (obtained at ambient pressure using an IR transmission microscope equipped with a BaF2 cell) showed large peak shifts (approximately 10 cm−1) with some vibrational modes in many samples comprising the cohort. These peak shifts are attributed to differences in t...

Research paper thumbnail of Commissioning process and acceptance test of a sub-harmonic protection relay

2017 70th Annual Conference for Protective Relay Engineers (CPRE), 2017

Numerous technical papers have been published discussing the topic of Sub-Synchronous Resonance (... more Numerous technical papers have been published discussing the topic of Sub-Synchronous Resonance (SSR) and more recently about new protection devices capable of detecting and protecting against the detrimental effects of SSR. The advent of such protection devices has created the new challenge of testing and commissioning such devices. Commissioning sub-harmonic protection devices require following a process that differs from the traditional testing and commissioning process of microprocessor devices. This paper presents the experiences of the authors during the commissioning of Sub-harmonic Protection Relays and describes the process that was followed prior to the site visit and then during the actual commissioning of the relay. The paper will review the following topics: • The characteristics of a Sub-Harmonic Protection Relay • The engineering process for the determination of settings • The determination of test cases to make sure all the features of the relay are properly tested • The use of a real time digital simulator for the preparation of COMTRADE files to be used during the relay testing • The process followed at site to commission the relay by using advanced relay test equipment capable of playing back COMTRADE files. During the commissioning process of sub-harmonic protection relays the authors discovered that there is very little understanding on SSR and SSCI phenomena, on the engineering behind the selection of settings for sub-harmonic protection IEDs and on the process of testing and commissioning such IEDs, hence the need to educate the Protection & Control community. The paper describes the use of software capable of simulating and modeling power systems, similar to PSCAD™/EMTDC™ or RTDS TM for the creation of test cases in COMTRADE format that will be used to test de relay. Prior to the creation of test cases, the process requires the review of power system simulation cases that were used to determine the relay settings in order to create COMTRADE test cases that will confirm that the relay responds as expected. The process requires testing for: • Sub-harmonic frequency ranges-making sure the relay does not misoperate for frequencies outside the desire frequency range • Sub-harmonic magnitudes-making sure the relay does not misoperate for sub-harmonics with magnitudes below the set thresholds • Protection features at the fundamental frequency

Research paper thumbnail of Application of infrared microscopy and alternating least squares to the forensic analysis of automotive paint chips

Journal of Chemometrics, 2020

To collect infrared (IR) absorbance spectra from an automotive paint chip with an IR imaging micr... more To collect infrared (IR) absorbance spectra from an automotive paint chip with an IR imaging microscope, it is a common practice to cast the paint chip in epoxy and then cross section it using a microtome to reveal the individual layers of paint. Ideally, the epoxy should present little or no spectral interference. However, the epoxy can infiltrate individual layers of the paint chip as it cures contaminating the IR spectra of the layers and impairing the accuracy of a search of each of these layers against an automotive paint library. In this study, we have demonstrated that automotive paint chips can be successfully cross sectioned without the use of embedding media. Sample preparation is easier, and more importantly, interfering peaks in the spectra due to the epoxy are eliminated. To demonstrate the advantages of this approach for sample preparation, IR image maps of four automotive paint chips that were not cast in epoxy prior to cross sectioning were collected. After each IR image was unfolded using an oblique transit to traverse the image, the spectra of the individual paint layers comprising the line map were reconstructed by alternating least squares. Comparing each recovered IR spectrum against a spectral library, we show that high quality spectral matches were obtained for spectra from the same line/model of the vehicle from which the paint sample originated. When the same paint chips were cast in epoxy prior to cross sectioning, high quality spectral matches could not always be obtained. K E Y W O R D S chemometrics, cross sectioning, forensic automotive paint analysis, microtome, multivariate curve resolution, spectral library matching, transmission infrared imaging microscopy 1 | INTRODUCTION Automotive paint is an important category of trace evidence as it can provide crucial links in the early phase of an investigation or evidence of association in a criminal proceeding. Automotive paint in the form of a chip is often the only evidence recovered at the crime-scene of a vehicle related fatality such as a hit-and-run where injury or death to a pedestrian has occurred. Studies 1,2 conducted by the Royal Canadian Mounted Police (RCMP) almost 45 years ago showed that automotive vehicles could be discriminated by directly comparing the color, layer sequence, and chemical composition of each individual layer in an original equipment manufacturer (OEM) paint system. To make these

Research paper thumbnail of Series Compensated Transmission Line Protection Using Pscad

International Journal of Advance Engineering and Research Development, 2017

In order to meet the high demand for power transmission capacity, some power companies have insta... more In order to meet the high demand for power transmission capacity, some power companies have installed series capacitor on power transmission line. The introduction of the capacitance in series with the line reactance allows reduction in line impedance, thus resulting increased power transmission capability. It provides the benefits of increased system capacity, reduced system losses and voltage regulation. The paper presents series compensated transmission line model by using PSCAD. Results are tested with different fault locations for compensated and without compensated transmission line. Performance of the developed method ensures that the proposed scheme gives the apparent effects when compensation is going to be added in the line.

Research paper thumbnail of Performance Evaluation of an Enhanced Bus Differential Protection Relay

2019 72nd Conference for Protective Relay Engineers (CPRE), 2019

The busbar protection relays typically implements low impedance percentage differential principle... more The busbar protection relays typically implements low impedance percentage differential principle using dual slope characteristics. These relays may sometimes misoperate in response to the CT saturation during close-in external faults, and the subsidence current present after clearing external faults. A primary reason for such misoperations is the fact that the traditional percentage differential principle relies exclusively on current magnitudes rather than directionality for tripping decisions. This paper evaluates the performance of an enhanced bus differential relay which uses different principles that distinguish between external and internal faults so as to enhance the security of differential protection. Extensive testing has been carried out to evaluate the effectiveness of the new principles in enhancing the security for external faults.

Research paper thumbnail of Solutions for Monitoring GIC Events Using a Digital Fault Recording System

The GMD (Geo Magnetic Disturbance) activity, which causes GIC (Geomagnetic Induced Current) and i... more The GMD (Geo Magnetic Disturbance) activity, which causes GIC (Geomagnetic Induced Current) and its impact, has been seriously looked into in many geographical areas across the globe. Specifically, the North American continent has more probability of impact with GIC as per the calculations and as well as the events that have happened in the past. It is clear that the GIC phenomenon causes widespread effects throughout the electrical grid. The electric field gradient and the induced current can flow over wide areas of power systems. This includes the entire possible closed electric circuit path between grounded points. This technical paper provides general information on GIC in power systems and describes the causes and sources of GIC and touch on the consequences on power transformers. In addition, it provides information on how to apply a power system monitoring device to monitor for the negative effect of GIC on power transformers.

Research paper thumbnail of Spectrophotometric Analysis of Food Colorants

Coloring agents or food dyes have been used to make food more attractive since ancient times. The... more Coloring agents or food dyes have been used to make food more attractive since ancient times. The detection and quantification of dyes in food samples remain a challenge for food scientists because present methods involve the use of expensive chromatographic separation techniques, such as the high-performance liquid chromatograph (HPLC). Alternatively, spectrophotometers are faster and less expensive than HPLC. Utilizing spectrophotometric methods would increase the efficiency of food safety assessments. In this article, we review the benefits and limitations of spectrophotometric methods which provide a promising tool for the direct quantification of dyes in food matrices.

Research paper thumbnail of Applicability of Synchrophasor Based Frequency Data for Protection and Control Applications

2019 72nd Conference for Protective Relay Engineers (CPRE), 2019

Synchrophasor based wide area monitoring, protection, and control applications are widely used al... more Synchrophasor based wide area monitoring, protection, and control applications are widely used all over the world. The latest IEEE synchro-phasor standard C37.118.1a-2014 provides necessary steady-state and dynamic performance requirements for two different application categories namely the "Protection (P) Class" and the "Metering (M) Class" [1-2]. Satisfactions of these application classes require inclusion of digital filters into the standard phasor calculations. Although the IEEE standard provides benchmark test cases for dynamic and steady state frequency measurements, from application point of view, it is essential to understand their applicability for various protection and control applications specified by authorities and standards such as NERC, BAL-0003-1. The information discussed in this paper is useful for users to understand the impact of the performance filters introduced in the latest synchro-phasor standard applicable for frequency related power system applications.