Pub Date : 2018-03-01DOI: 10.1109/CPRE.2018.8349810
J. Blumschein, Y. Yelgin
Ground fault protection is widely used to protect transmission and distribution lines in case of ground faults. Combined with a directional element and used in a teleprotection scheme ground fault protection can detect and isolate even high resistive ground faults which are not seen by distance protection. Today in general the directional element of ground fault protection is based on zero sequence components or negative sequence components. There is no clear advice which kind of polarization should be preferred for a special application. However there are a lot of maloperations due to incorrect result of the directional element of ground fault protection using either zero sequence or negative sequence quantities. Analyzing numerous fault records it seems obvious that these problems with the directional elements cannot be solved using either zero sequence or negative sequence because these quantities are sometimes very small or not related to the fault. One great advantage of numerical relays is that these relays measure all the voltages and currents of a three phase system. Analyzing fault records related to complicate cases for ground fault protection it can be seen that there is much more information about the fault than used by today's implementations of ground fault protection. For instance the location of the impedance in the complex plane often gives a clear indication about the direction to fault. This paper suggests a new design of ground fault protection using this additional information given by the numerical relays. The starting condition for the ground fault protection remains a threshold of zero sequence current. Once this threshold is exceeded a multi-criteria phase selector selects the faulted phase. Several criteria based on magnitudes of voltages and currents, changes in voltages and currents, symmetrical components and impedances are applied in parallel. The results of each single criterion are weighted and combined to get a final result for the selection of the faulted phase. Using the information of the faulted phase a multi-criteria directional element is suggested to estimate the direction to the fault. Different criteria based on actual voltages, memorized voltages, symmetrical components and delta quantities are applied in parallel. The final result is obtained by the multi-criteria directional element as a weighted combination of the result of each single criterion. This paper explains the new algorithm in more detail and illustrates the advantages of the proposed method using some real fault records. With the new design the ground fault protection takes a lot of advantages regarding phase selection and directional element from the distance protection. The main difference between distance protection and ground fault protection remains the different grading. For distance protection the sensitivity is limited by the resistive reach. The basic principle for grading of ground fault protection remains a simple threshold of ze
{"title":"New design of ground fault protection","authors":"J. Blumschein, Y. Yelgin","doi":"10.1109/CPRE.2018.8349810","DOIUrl":"https://doi.org/10.1109/CPRE.2018.8349810","url":null,"abstract":"Ground fault protection is widely used to protect transmission and distribution lines in case of ground faults. Combined with a directional element and used in a teleprotection scheme ground fault protection can detect and isolate even high resistive ground faults which are not seen by distance protection. Today in general the directional element of ground fault protection is based on zero sequence components or negative sequence components. There is no clear advice which kind of polarization should be preferred for a special application. However there are a lot of maloperations due to incorrect result of the directional element of ground fault protection using either zero sequence or negative sequence quantities. Analyzing numerous fault records it seems obvious that these problems with the directional elements cannot be solved using either zero sequence or negative sequence because these quantities are sometimes very small or not related to the fault. One great advantage of numerical relays is that these relays measure all the voltages and currents of a three phase system. Analyzing fault records related to complicate cases for ground fault protection it can be seen that there is much more information about the fault than used by today's implementations of ground fault protection. For instance the location of the impedance in the complex plane often gives a clear indication about the direction to fault. This paper suggests a new design of ground fault protection using this additional information given by the numerical relays. The starting condition for the ground fault protection remains a threshold of zero sequence current. Once this threshold is exceeded a multi-criteria phase selector selects the faulted phase. Several criteria based on magnitudes of voltages and currents, changes in voltages and currents, symmetrical components and impedances are applied in parallel. The results of each single criterion are weighted and combined to get a final result for the selection of the faulted phase. Using the information of the faulted phase a multi-criteria directional element is suggested to estimate the direction to the fault. Different criteria based on actual voltages, memorized voltages, symmetrical components and delta quantities are applied in parallel. The final result is obtained by the multi-criteria directional element as a weighted combination of the result of each single criterion. This paper explains the new algorithm in more detail and illustrates the advantages of the proposed method using some real fault records. With the new design the ground fault protection takes a lot of advantages regarding phase selection and directional element from the distance protection. The main difference between distance protection and ground fault protection remains the different grading. For distance protection the sensitivity is limited by the resistive reach. The basic principle for grading of ground fault protection remains a simple threshold of ze","PeriodicalId":285875,"journal":{"name":"2018 71st Annual Conference for Protective Relay Engineers (CPRE)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125748487","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-03-01DOI: 10.1109/CPRE.2018.8349789
K. Fodero, C. Huntley, P. Robertson
There is a growing trend in the power utility industry to move away from traditional synchronous optical network/synchronous digital hierarchy (SONET/SDH) systems for wide-area network (WAN) communications. Information technology (IT) teams and equipment manufacturers are encouraging utility communications engineers to implement Ethernet-based packet transport solutions that offer greater bandwidth efficiency. This technology migration comes with a challenge; engineers must now figure out how to design packet-based pilot channels that still meet the strict performance and determinism requirements essential for supporting protection applications. To solve this problem, this paper introduces a deterministic packet transport method for achieving guaranteed latency for critical traffic being transported over packet-based WANs that is compatible with both multiprotocol label switching (MPLS) and Carrier Ethernet systems. Latency, asymmetry, and packet delay variation (jitter) performance data are discussed to show the ability of the deterministic packet transport method to support a line current differential protection channel across mixed transport network topologies.
{"title":"Deterministic communications for protection applications over packet-based wide-area networks","authors":"K. Fodero, C. Huntley, P. Robertson","doi":"10.1109/CPRE.2018.8349789","DOIUrl":"https://doi.org/10.1109/CPRE.2018.8349789","url":null,"abstract":"There is a growing trend in the power utility industry to move away from traditional synchronous optical network/synchronous digital hierarchy (SONET/SDH) systems for wide-area network (WAN) communications. Information technology (IT) teams and equipment manufacturers are encouraging utility communications engineers to implement Ethernet-based packet transport solutions that offer greater bandwidth efficiency. This technology migration comes with a challenge; engineers must now figure out how to design packet-based pilot channels that still meet the strict performance and determinism requirements essential for supporting protection applications. To solve this problem, this paper introduces a deterministic packet transport method for achieving guaranteed latency for critical traffic being transported over packet-based WANs that is compatible with both multiprotocol label switching (MPLS) and Carrier Ethernet systems. Latency, asymmetry, and packet delay variation (jitter) performance data are discussed to show the ability of the deterministic packet transport method to support a line current differential protection channel across mixed transport network topologies.","PeriodicalId":285875,"journal":{"name":"2018 71st Annual Conference for Protective Relay Engineers (CPRE)","volume":"255 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130787892","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-03-01DOI: 10.1109/CPRE.2018.8349798
R. Chowdhury, D. Finney, N. Fischer, Jason Young
Because of the nature of stator winding construction, insulation failure typically results in a ground fault. Other failures — such as interturn, interbranch, and series faults — if undetected usually evolve into ground faults. Since these failure mechanisms can occur on any portion of the stator winding, 100 percent ground fault protection of the stator winding is recommended. Various third-harmonic schemes have been used to provide neutral-side stator winding protection for high-impedance grounded generators. Applying such schemes in conjunction with a fundamental neutral overvoltage (59N) element, which protects the top 85–95 percent of the stator winding, provides ground fault protection coverage for 100 percent of the stator winding when sufficient third harmonic is available. This paper compares the performance of different third-harmonic schemes and shows how these schemes can be applied to provide secure and sensitive stator winding coverage.
{"title":"Generator third-harmonic protection explained","authors":"R. Chowdhury, D. Finney, N. Fischer, Jason Young","doi":"10.1109/CPRE.2018.8349798","DOIUrl":"https://doi.org/10.1109/CPRE.2018.8349798","url":null,"abstract":"Because of the nature of stator winding construction, insulation failure typically results in a ground fault. Other failures — such as interturn, interbranch, and series faults — if undetected usually evolve into ground faults. Since these failure mechanisms can occur on any portion of the stator winding, 100 percent ground fault protection of the stator winding is recommended. Various third-harmonic schemes have been used to provide neutral-side stator winding protection for high-impedance grounded generators. Applying such schemes in conjunction with a fundamental neutral overvoltage (59N) element, which protects the top 85–95 percent of the stator winding, provides ground fault protection coverage for 100 percent of the stator winding when sufficient third harmonic is available. This paper compares the performance of different third-harmonic schemes and shows how these schemes can be applied to provide secure and sensitive stator winding coverage.","PeriodicalId":285875,"journal":{"name":"2018 71st Annual Conference for Protective Relay Engineers (CPRE)","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132515612","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-03-01DOI: 10.1109/CPRE.2018.8349772
Casey Thomas, Joe Perez, Luke Hankins, Haley Tribur
Compliance with NERC PRC-027-1 has brought increasing stress to utilities as they work to establish a defined process for performing relay setting development and coordination at regular intervals. While current software programs attempt to aid utilities in complying with this new standard, they only offer an overwhelming and unmanageable report of coordination study results. None of the current programs provides a work flow from relay setting development to wide area coordination, which is what utilities desperately need. In this paper, we present an innovative process to comply with the R1, R2, and R3 requirements of PRC-027-1 through the use of an automated solution.
{"title":"An innovative and automated solution for NERC PRC-027-1 compliance","authors":"Casey Thomas, Joe Perez, Luke Hankins, Haley Tribur","doi":"10.1109/CPRE.2018.8349772","DOIUrl":"https://doi.org/10.1109/CPRE.2018.8349772","url":null,"abstract":"Compliance with NERC PRC-027-1 has brought increasing stress to utilities as they work to establish a defined process for performing relay setting development and coordination at regular intervals. While current software programs attempt to aid utilities in complying with this new standard, they only offer an overwhelming and unmanageable report of coordination study results. None of the current programs provides a work flow from relay setting development to wide area coordination, which is what utilities desperately need. In this paper, we present an innovative process to comply with the R1, R2, and R3 requirements of PRC-027-1 through the use of an automated solution.","PeriodicalId":285875,"journal":{"name":"2018 71st Annual Conference for Protective Relay Engineers (CPRE)","volume":"439 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132785868","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-03-01DOI: 10.1109/CPRE.2018.8349814
Mohit Sharma, V. Shanmugasundaram
Various combinations of voltages and currents are possible in the power system in an event of fault. Distance relays use these voltage and current phasors, obtained from PTs and CTs, to calculate impedance. The relay operates when the calculated impedance is below the reach or set impedance. The operation can be better understood when plotted on an impedance plane. Mho circles and quadrilateral characteristic are essentially the most popular characteristics used all across the world since they are inherently directional and provide well defined reach with minimal over reaching and under reaching errors. All the impedance points that lie within the characteristic are considered operating points.
{"title":"Performance analysis of distance protection using different impedance calculation methods","authors":"Mohit Sharma, V. Shanmugasundaram","doi":"10.1109/CPRE.2018.8349814","DOIUrl":"https://doi.org/10.1109/CPRE.2018.8349814","url":null,"abstract":"Various combinations of voltages and currents are possible in the power system in an event of fault. Distance relays use these voltage and current phasors, obtained from PTs and CTs, to calculate impedance. The relay operates when the calculated impedance is below the reach or set impedance. The operation can be better understood when plotted on an impedance plane. Mho circles and quadrilateral characteristic are essentially the most popular characteristics used all across the world since they are inherently directional and provide well defined reach with minimal over reaching and under reaching errors. All the impedance points that lie within the characteristic are considered operating points.","PeriodicalId":285875,"journal":{"name":"2018 71st Annual Conference for Protective Relay Engineers (CPRE)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133348567","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-03-01DOI: 10.1109/CPRE.2018.8349795
H. Vardhan, R. Ramlachan, Wojciech Szela, Edward Gdowik
Though IEC 61850 GOOSE has been in use for a while for various applications such as controls, interlocking, blocking etc. with substations across the world running successfully in a multi-vendor environment but IEC 61850-9-2 Sampled values and switched Ethernet process bus have yet to gain popularity. The use of NCITs (Non-Conventional Instrument transformers) have been limited to some niche application so far, such as measuring GICs, Open Phase detection, measuring very low magnitude AC, measuring DC etc. Introduction of IEC 61850 process bus and availability of NCITs have led to the way to real word deployment of Digital Substations. There have been several papers published and studies done on the design benefits and various tangible and non-tangible savings attained in digital substations as compared to Conventional Substations. This has interested utilities across the world to start deploying digital substations as pilot projects to realize the real-time benefits, understand the difficulties or ease to deploy such systems and have practical experience while comparing digital substation to a conventional system. This paper discusses PECOs perspective in deploying one of the first digital substation pilot projects in North America. The pilot project is installed on a 230kV line connected to the ring bus managed by PECO, Philadelphia. The main aim of the project is to evaluate and learn the state of the art digital substation technology and compare the various aspects to a conventional substation. The project involves primary optical sensors, merging Units, Protection IEDs supporting 9-2LE, IEEE 1588 Clocks, Substation Servers and Substation hardened Ethernet switches.
{"title":"Deploying digital substations: Experience with a digital substation pilot in North America","authors":"H. Vardhan, R. Ramlachan, Wojciech Szela, Edward Gdowik","doi":"10.1109/CPRE.2018.8349795","DOIUrl":"https://doi.org/10.1109/CPRE.2018.8349795","url":null,"abstract":"Though IEC 61850 GOOSE has been in use for a while for various applications such as controls, interlocking, blocking etc. with substations across the world running successfully in a multi-vendor environment but IEC 61850-9-2 Sampled values and switched Ethernet process bus have yet to gain popularity. The use of NCITs (Non-Conventional Instrument transformers) have been limited to some niche application so far, such as measuring GICs, Open Phase detection, measuring very low magnitude AC, measuring DC etc. Introduction of IEC 61850 process bus and availability of NCITs have led to the way to real word deployment of Digital Substations. There have been several papers published and studies done on the design benefits and various tangible and non-tangible savings attained in digital substations as compared to Conventional Substations. This has interested utilities across the world to start deploying digital substations as pilot projects to realize the real-time benefits, understand the difficulties or ease to deploy such systems and have practical experience while comparing digital substation to a conventional system. This paper discusses PECOs perspective in deploying one of the first digital substation pilot projects in North America. The pilot project is installed on a 230kV line connected to the ring bus managed by PECO, Philadelphia. The main aim of the project is to evaluate and learn the state of the art digital substation technology and compare the various aspects to a conventional substation. The project involves primary optical sensors, merging Units, Protection IEDs supporting 9-2LE, IEEE 1588 Clocks, Substation Servers and Substation hardened Ethernet switches.","PeriodicalId":285875,"journal":{"name":"2018 71st Annual Conference for Protective Relay Engineers (CPRE)","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121766370","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The advantages of a dedicated, standalone DFR are well known: natively synchronized fault records, large record storage capabilities, high sampling rates, numerous types of triggers, and large numbers of analog and digital recording channels. The main disadvantage to the dedicated DFR is cost: a dedicated DFR must be directly wired to every current, voltage, and status point, resulting in an installed project cost easily 10 times the material cost of the DFR itself. For this reason, electric utilities have been moving away from dedicated, standalone DFRs.
{"title":"The return of the dedicated DFR how IEC 61850 process bus simplifies DFR installation","authors":"R. Hunt, L. B. de Oliveira","doi":"10.1049/JOE.2018.0240","DOIUrl":"https://doi.org/10.1049/JOE.2018.0240","url":null,"abstract":"The advantages of a dedicated, standalone DFR are well known: natively synchronized fault records, large record storage capabilities, high sampling rates, numerous types of triggers, and large numbers of analog and digital recording channels. The main disadvantage to the dedicated DFR is cost: a dedicated DFR must be directly wired to every current, voltage, and status point, resulting in an installed project cost easily 10 times the material cost of the DFR itself. For this reason, electric utilities have been moving away from dedicated, standalone DFRs.","PeriodicalId":285875,"journal":{"name":"2018 71st Annual Conference for Protective Relay Engineers (CPRE)","volume":"33 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120992496","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-03-01DOI: 10.1109/CPRE.2018.8349792
D. Finney, D. Haas
Power system events (such as starting a motor), a fault on the motor supply, or a switching event (such as the transfer of a motor from a primary to an alternate source) all expose a motor to transients. The electromagnetic torque response can be used as a measure of the impact of an event on the motor. A very large torque during a switching event can help identify improper switching controls or even the need to inspect a motor for damage. Motor torque calculated during normal motor starts and transfers can be trended to identify developing problems. While measuring the mechanical torque on the shaft of the machine can be challenging, it is possible to calculate the electromagnetic torque or air-gap torque directly from the motor terminal voltage and stator current. This paper discusses how electromagnetic torque can be calculated from oscillographic event report data obtained from digital motor protection. Several example cases are shared.
{"title":"Electromagnetic torque from event report data — A measure of machine performance","authors":"D. Finney, D. Haas","doi":"10.1109/CPRE.2018.8349792","DOIUrl":"https://doi.org/10.1109/CPRE.2018.8349792","url":null,"abstract":"Power system events (such as starting a motor), a fault on the motor supply, or a switching event (such as the transfer of a motor from a primary to an alternate source) all expose a motor to transients. The electromagnetic torque response can be used as a measure of the impact of an event on the motor. A very large torque during a switching event can help identify improper switching controls or even the need to inspect a motor for damage. Motor torque calculated during normal motor starts and transfers can be trended to identify developing problems. While measuring the mechanical torque on the shaft of the machine can be challenging, it is possible to calculate the electromagnetic torque or air-gap torque directly from the motor terminal voltage and stator current. This paper discusses how electromagnetic torque can be calculated from oscillographic event report data obtained from digital motor protection. Several example cases are shared.","PeriodicalId":285875,"journal":{"name":"2018 71st Annual Conference for Protective Relay Engineers (CPRE)","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115527873","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-03-01DOI: 10.1109/CPRE.2018.8349833
J. Theron, Amit Pal, A. Varghese
High impedance faults are generally not detected by conventional protection functions like over current, ground fault, distance, differential etc. because of the magnitude of impedance involved in the fault path and the nature and characteristic of the fault current are special and different than the conventional fault current profiles. Each type of high impedance fault is unique in terms of magnitude of fault current, nature, characteristic and waveshape. Majority of the high impedance faults are single phase to ground faults but this can involve phase to phase elements as well. Because of the inability of the conventional protection functions to detect high impedance faults especially high impedance phase to ground faults, the electrical conductor remains live under such condition and as can be imagined, poses a huge and significant risk to wild life and more importantly human life. Atmospheric and geographical conditions have a significant role to play in high impedance phase to ground faults since they have a direct impact on the magnitude and characteristic of the fault current. This paper describes different techniques to detect high impedance phase to ground faults and focuses on the proven algorithms that have been implemented in protection relays, had been verified by real site tests and fault inception on live power lines. The paper is broadly organized as a tutorial. The characteristics of high impedance faults and the challenges involved in detecting them are described first. The paper then goes on to detail some of the important techniques in use for high impedance fault detection highlighting their strengths and weaknesses, and some modern approaches proposed to improve the dependability of protection schemes. In particular, a technique combining the fundamental and harmonic analysis of the fault waveform is presented, along with its performance in field trials carried out in co-operation with utilities.
{"title":"Tutorial on high impedance fault detection","authors":"J. Theron, Amit Pal, A. Varghese","doi":"10.1109/CPRE.2018.8349833","DOIUrl":"https://doi.org/10.1109/CPRE.2018.8349833","url":null,"abstract":"High impedance faults are generally not detected by conventional protection functions like over current, ground fault, distance, differential etc. because of the magnitude of impedance involved in the fault path and the nature and characteristic of the fault current are special and different than the conventional fault current profiles. Each type of high impedance fault is unique in terms of magnitude of fault current, nature, characteristic and waveshape. Majority of the high impedance faults are single phase to ground faults but this can involve phase to phase elements as well. Because of the inability of the conventional protection functions to detect high impedance faults especially high impedance phase to ground faults, the electrical conductor remains live under such condition and as can be imagined, poses a huge and significant risk to wild life and more importantly human life. Atmospheric and geographical conditions have a significant role to play in high impedance phase to ground faults since they have a direct impact on the magnitude and characteristic of the fault current. This paper describes different techniques to detect high impedance phase to ground faults and focuses on the proven algorithms that have been implemented in protection relays, had been verified by real site tests and fault inception on live power lines. The paper is broadly organized as a tutorial. The characteristics of high impedance faults and the challenges involved in detecting them are described first. The paper then goes on to detail some of the important techniques in use for high impedance fault detection highlighting their strengths and weaknesses, and some modern approaches proposed to improve the dependability of protection schemes. In particular, a technique combining the fundamental and harmonic analysis of the fault waveform is presented, along with its performance in field trials carried out in co-operation with utilities.","PeriodicalId":285875,"journal":{"name":"2018 71st Annual Conference for Protective Relay Engineers (CPRE)","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114841639","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-03-01DOI: 10.1109/CPRE.2018.8349812
Shashidhar Reddy Sathu, N. Fischer, B. Johnson
The short circuit behavior of the early generation wind turbines depends solely on the physical characteristics of the machine. Conventional protection schemes can be applied to provide protection to those wind farms. But full converter based Type 4 wind turbine generators have complex fault current characteristics governed by the converter controls, with fault current responses very different from synchronous generators. The use of relays with conventional protection and supervision schemes may cause misoperation. This paper presents preliminary concepts for a new protection scheme based on converter control system behavior and tested with simulation of a Type 4 wind turbine in RTDS.
{"title":"New protection scheme for type 4 wind turbines","authors":"Shashidhar Reddy Sathu, N. Fischer, B. Johnson","doi":"10.1109/CPRE.2018.8349812","DOIUrl":"https://doi.org/10.1109/CPRE.2018.8349812","url":null,"abstract":"The short circuit behavior of the early generation wind turbines depends solely on the physical characteristics of the machine. Conventional protection schemes can be applied to provide protection to those wind farms. But full converter based Type 4 wind turbine generators have complex fault current characteristics governed by the converter controls, with fault current responses very different from synchronous generators. The use of relays with conventional protection and supervision schemes may cause misoperation. This paper presents preliminary concepts for a new protection scheme based on converter control system behavior and tested with simulation of a Type 4 wind turbine in RTDS.","PeriodicalId":285875,"journal":{"name":"2018 71st Annual Conference for Protective Relay Engineers (CPRE)","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127888435","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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