Pub Date : 2018-03-01DOI: 10.1109/CPRE.2018.8349816
J. Patten, Majid Malki, Matt Jones
Tapped transmission lines are quite common as they provide a low cost solution to connect remote loads without incurring the prohibitive cost of building a substation and the associated protective equipment. However, adding a tap in the line complicates the protection scheme and introduces unique challenges for the protection engineer. Protecting transmission lines with long taps is even more challenging. The effects of infeed can result in a fault on the tap having a larger apparent impedance than a fault at the remote end of the line. Setting relay elements to provide adequate coverage of long taps can cause coordination issues with remote lines. This paper will illustrate, through some real world examples, the issue of protecting transmission lines with long taps and discuss some options for protecting long taps. Three examples will be used to explore different scenarios with tapped transmission lines: •The first example will look at how a redundant POTT scheme is used to protect a line with a 15 mile tap in the middle of a 20 mile 69 kV sub-transmission line. •The second example will highlight the effect of the location of the tap on the line by examining a line with a tap located at 95% of the line length from one end. •The third example will explore how the relative strength of the system will impact the protection of lines with a long tap. In this example, one terminal is much stronger source than the other. The system strength on the line under study will be determined by calculation of the source impedance ratio. A short circuit program with automated scripts will be used to illustrate these examples and run different contingency scenarios. Sensitivity and coordination scripts will be run to check the validity of the proposed settings. The last part of the paper will discuss the issues related to fault location on transmission lines with long taps.
{"title":"Protection challenges for transmission lines with long taps","authors":"J. Patten, Majid Malki, Matt Jones","doi":"10.1109/CPRE.2018.8349816","DOIUrl":"https://doi.org/10.1109/CPRE.2018.8349816","url":null,"abstract":"Tapped transmission lines are quite common as they provide a low cost solution to connect remote loads without incurring the prohibitive cost of building a substation and the associated protective equipment. However, adding a tap in the line complicates the protection scheme and introduces unique challenges for the protection engineer. Protecting transmission lines with long taps is even more challenging. The effects of infeed can result in a fault on the tap having a larger apparent impedance than a fault at the remote end of the line. Setting relay elements to provide adequate coverage of long taps can cause coordination issues with remote lines. This paper will illustrate, through some real world examples, the issue of protecting transmission lines with long taps and discuss some options for protecting long taps. Three examples will be used to explore different scenarios with tapped transmission lines: •The first example will look at how a redundant POTT scheme is used to protect a line with a 15 mile tap in the middle of a 20 mile 69 kV sub-transmission line. •The second example will highlight the effect of the location of the tap on the line by examining a line with a tap located at 95% of the line length from one end. •The third example will explore how the relative strength of the system will impact the protection of lines with a long tap. In this example, one terminal is much stronger source than the other. The system strength on the line under study will be determined by calculation of the source impedance ratio. A short circuit program with automated scripts will be used to illustrate these examples and run different contingency scenarios. Sensitivity and coordination scripts will be run to check the validity of the proposed settings. The last part of the paper will discuss the issues related to fault location on transmission lines with long taps.","PeriodicalId":285875,"journal":{"name":"2018 71st Annual Conference for Protective Relay Engineers (CPRE)","volume":"45 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":"134402349","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.2018.8349787
Brian Ehsani, J. Hulme
This paper analyzes the effects of reducing tripping times on the cost of a transmission system. A range of trip times are examined to demonstrate the difference in the initial price tag of a transmission system as well as the ongoing cost. The increased cost of a slower tripping scheme is analyzed by investigating the relationship between substation ground grid and transmission line neutral conductor sizing and cost.
{"title":"Cost benefit analysis of faster transmission system protection systems: Presented at the 71st annual conference for protective relay engineers","authors":"Brian Ehsani, J. Hulme","doi":"10.1109/CPRE.2018.8349787","DOIUrl":"https://doi.org/10.1109/CPRE.2018.8349787","url":null,"abstract":"This paper analyzes the effects of reducing tripping times on the cost of a transmission system. A range of trip times are examined to demonstrate the difference in the initial price tag of a transmission system as well as the ongoing cost. The increased cost of a slower tripping scheme is analyzed by investigating the relationship between substation ground grid and transmission line neutral conductor sizing and cost.","PeriodicalId":285875,"journal":{"name":"2018 71st Annual Conference for Protective Relay Engineers (CPRE)","volume":"27 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":"125202263","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.2018.8349830
K. Donahoe
At the 44th Annual Conference for Protective Relay Engineers in 1991, Walt Elmore presented the paper “Ways to Assure the Improper Operation of Transformer Differential Relays.” This paper applies the same approach to microprocessor relays. Relay designers work very hard to develop microprocessor relays that will be secure and dependable. However, a considerable amount of background and experience is required to apply them correctly. There is a limited number of correct ways to connect and apply a microprocessor relay and literally hundreds of ways to connect them improperly. Wrong connections or applications generally manifest themselves in an undesired trip or failure to trip. Often, unfortunately, this doesn't happen on first energization but rather during a fault when proper operation is most needed or during load periods when false operations are to be avoided. The six ways to ensure improper operation of microprocessor relays are presented with examples of each. The six ways are: 1. Fail to consider how the relay is set. 2. Fail to consider how the relay acts. 3. Fail to consider how the relay measures the power system. 4. Fail to consider how the relay operates the control system. 5. Fail to consider how the power system acts. 6. Fail to consider how the power system is operated. Applications of the Six Ways to design, testing and troubleshooting are discussed.
{"title":"The six ways to ensure improper operation of microprocessor relays","authors":"K. Donahoe","doi":"10.1109/CPRE.2018.8349830","DOIUrl":"https://doi.org/10.1109/CPRE.2018.8349830","url":null,"abstract":"At the 44th Annual Conference for Protective Relay Engineers in 1991, Walt Elmore presented the paper “Ways to Assure the Improper Operation of Transformer Differential Relays.” This paper applies the same approach to microprocessor relays. Relay designers work very hard to develop microprocessor relays that will be secure and dependable. However, a considerable amount of background and experience is required to apply them correctly. There is a limited number of correct ways to connect and apply a microprocessor relay and literally hundreds of ways to connect them improperly. Wrong connections or applications generally manifest themselves in an undesired trip or failure to trip. Often, unfortunately, this doesn't happen on first energization but rather during a fault when proper operation is most needed or during load periods when false operations are to be avoided. The six ways to ensure improper operation of microprocessor relays are presented with examples of each. The six ways are: 1. Fail to consider how the relay is set. 2. Fail to consider how the relay acts. 3. Fail to consider how the relay measures the power system. 4. Fail to consider how the relay operates the control system. 5. Fail to consider how the power system acts. 6. Fail to consider how the power system is operated. Applications of the Six Ways to design, testing and troubleshooting are discussed.","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":"131405123","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.2018.8349799
M. Zapella, L. Oliveira, R. Hunt
The demand for accurate time synchronization available 24/7 increases with the growth of critical substation applications, such as phasor measurement, merging units, traveling-wave fault location and current differential protection schemes. In order to yield the best accuracy and granularity from such applications, the use of a common, reliable and precision-time reference is essential.
{"title":"GPS and GLONASS constellations for better time synchronizing reliability","authors":"M. Zapella, L. Oliveira, R. Hunt","doi":"10.1109/CPRE.2018.8349799","DOIUrl":"https://doi.org/10.1109/CPRE.2018.8349799","url":null,"abstract":"The demand for accurate time synchronization available 24/7 increases with the growth of critical substation applications, such as phasor measurement, merging units, traveling-wave fault location and current differential protection schemes. In order to yield the best accuracy and granularity from such applications, the use of a common, reliable and precision-time reference is essential.","PeriodicalId":285875,"journal":{"name":"2018 71st Annual Conference for Protective Relay Engineers (CPRE)","volume":"43 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":"122654688","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.2018.8349805
M. Boecker, Genardo T. Corpuz, Glenn Hargrave, Swagata Das, N. Fischer, V. Skendzic
This paper describes an event in which lightning struck and discharged current into the phase conductor of a 345 kV transmission line. The magnitude of the lightning discharge was insufficient to lead to a flashover (line insulation breakdown). The paper examines and explains the response of two different line current differential protective relays to this event that was inside their zone of protection.
{"title":"Line current differential relay response to a direct lightning strike on a phase conductor","authors":"M. Boecker, Genardo T. Corpuz, Glenn Hargrave, Swagata Das, N. Fischer, V. Skendzic","doi":"10.1109/CPRE.2018.8349805","DOIUrl":"https://doi.org/10.1109/CPRE.2018.8349805","url":null,"abstract":"This paper describes an event in which lightning struck and discharged current into the phase conductor of a 345 kV transmission line. The magnitude of the lightning discharge was insufficient to lead to a flashover (line insulation breakdown). The paper examines and explains the response of two different line current differential protective relays to this event that was inside their zone of protection.","PeriodicalId":285875,"journal":{"name":"2018 71st Annual Conference for Protective Relay Engineers (CPRE)","volume":"112 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":"123198004","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.2018.8349826
B. Vandiver, Peter Rietmann
The paper identifies how substation automation systems using IEC 61850 can be engineered and deployed in a standardized and efficient way using flexible naming extensions. This facilitates interoperability between different vendor IEDs and other substation automation systems. This allows a standardized way that a utility can engineer their substation automation systems with a model that they are always familiar with bringing standardization, efficiency, and time savings in the substation automation engineering process and throughout its entire life-cycle.
{"title":"Standardizing protection systems with flexible naming extensions of IEC 61850 functions","authors":"B. Vandiver, Peter Rietmann","doi":"10.1109/CPRE.2018.8349826","DOIUrl":"https://doi.org/10.1109/CPRE.2018.8349826","url":null,"abstract":"The paper identifies how substation automation systems using IEC 61850 can be engineered and deployed in a standardized and efficient way using flexible naming extensions. This facilitates interoperability between different vendor IEDs and other substation automation systems. This allows a standardized way that a utility can engineer their substation automation systems with a model that they are always familiar with bringing standardization, efficiency, and time savings in the substation automation engineering process and throughout its entire life-cycle.","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":"132358856","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.2018.8349771
S. Chase, Sumit Sawai, Amol Kathe
Protection engineers are often interested in calculating the steady-state voltages and currents on faulted transmission lines. This necessitates the use of accurate fault solution techniques. The most commonly taught and used methods involve symmetrical components. Symmetrical components are advantageous in that they yield multiple decoupled systems that are simple to solve. This simplicity was crucial before the advent of digital computers. With modern computers, it is equally easy to perform calculations with phase components (A, B, C) or with symmetrical components (positive, negative, zero). With symmetrical components, different circuit topologies must be used for different fault types, which can be inconvenient in practice. Additionally, symmetrical component techniques commonly assume line transposition and give oversimplified results for real-life cases. This paper presents phase-domain solution methods as an alternative to symmetrical components. Phase-domain analysis allows all ten common shunt faults to be modeled using a single circuit topology. In exchange for this convenience, the phase-domain approach must account for mutual coupling between the three phases of a transmission line. However, this in turn allows phase-domain analysis to be used to model untransposed transmission lines without compromising the accuracy of the solution. This paper presents a general derivation for a steady-state, phase-domain transmission line solution and illustrates its practical use through several examples. Steady-state signals can be reliably used for testing traditional phasor-based relays. This steady-state solution is then translated into a time-domain equivalent, which numerically solves differential equations to accurately model the transition between prefault and fault states. Accurate modeling of state transitions makes this solution suitable for testing relays that use incremental quantities.
{"title":"Analyzing faulted transmission lines: Phase components as an alternative to symmetrical components","authors":"S. Chase, Sumit Sawai, Amol Kathe","doi":"10.1109/CPRE.2018.8349771","DOIUrl":"https://doi.org/10.1109/CPRE.2018.8349771","url":null,"abstract":"Protection engineers are often interested in calculating the steady-state voltages and currents on faulted transmission lines. This necessitates the use of accurate fault solution techniques. The most commonly taught and used methods involve symmetrical components. Symmetrical components are advantageous in that they yield multiple decoupled systems that are simple to solve. This simplicity was crucial before the advent of digital computers. With modern computers, it is equally easy to perform calculations with phase components (A, B, C) or with symmetrical components (positive, negative, zero). With symmetrical components, different circuit topologies must be used for different fault types, which can be inconvenient in practice. Additionally, symmetrical component techniques commonly assume line transposition and give oversimplified results for real-life cases. This paper presents phase-domain solution methods as an alternative to symmetrical components. Phase-domain analysis allows all ten common shunt faults to be modeled using a single circuit topology. In exchange for this convenience, the phase-domain approach must account for mutual coupling between the three phases of a transmission line. However, this in turn allows phase-domain analysis to be used to model untransposed transmission lines without compromising the accuracy of the solution. This paper presents a general derivation for a steady-state, phase-domain transmission line solution and illustrates its practical use through several examples. Steady-state signals can be reliably used for testing traditional phasor-based relays. This steady-state solution is then translated into a time-domain equivalent, which numerically solves differential equations to accurately model the transition between prefault and fault states. Accurate modeling of state transitions makes this solution suitable for testing relays that use incremental quantities.","PeriodicalId":285875,"journal":{"name":"2018 71st Annual Conference for Protective Relay Engineers (CPRE)","volume":"53 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":"116959763","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.2018.8349817
N. Perera, R. Midence, V. Liyanage
The Sub Synchronous Torsional Interaction (SSTI) conditions occurred due to the interactions of the generator-turbine systems and devices such as series compensated systems and HVDC systems has identified as harmful condition to avoid. Although it is a common practice to study and mitigate possibilities of SSTI conditions at system level designs, the power systems are not fully immune to SSTI conditions. This paper investigates the applicability of a numerical sub-harmonic relay for providing the protection against such SSTI conditions. Performance (accuracy and speed) of the proposed solution is investigated using various SSTI conditions injected into the relay.
{"title":"Protection for sub synchronous torsional interaction conditions using an industrial sub-harmonic relay","authors":"N. Perera, R. Midence, V. Liyanage","doi":"10.1109/CPRE.2018.8349817","DOIUrl":"https://doi.org/10.1109/CPRE.2018.8349817","url":null,"abstract":"The Sub Synchronous Torsional Interaction (SSTI) conditions occurred due to the interactions of the generator-turbine systems and devices such as series compensated systems and HVDC systems has identified as harmful condition to avoid. Although it is a common practice to study and mitigate possibilities of SSTI conditions at system level designs, the power systems are not fully immune to SSTI conditions. This paper investigates the applicability of a numerical sub-harmonic relay for providing the protection against such SSTI conditions. Performance (accuracy and speed) of the proposed solution is investigated using various SSTI conditions injected into the relay.","PeriodicalId":285875,"journal":{"name":"2018 71st Annual Conference for Protective Relay Engineers (CPRE)","volume":"85 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":"127029185","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 : 1900-01-01DOI: 10.1109/cpre.2018.8349784
This paper will discuss the differences in types of testing philosophies, test set units and different automated testing software used across different utilities. These differences typically arise due to legacy procedures, economic and scalability reasons and difference in understanding of industry best practices. Utilities have their own ways of commissioning and testing protection relays. Some utilities provide logic diagrams along with protection standards and during the commissioning stage the relay testers are expected to test the internal logic and perform dynamic tests, and end to end tests for the protection scheme. Other utilities require the relay techs to only perform static tests and functional tests in order to put the protection in-service. Utilities use different test sets with various capabilities to perform their commissioning and maintenance tests. This paper will present a detailed analysis of some of these differences and discuss their advantages and disadvantages.
{"title":"Comparing protective-relaying commissioning and test philosophies and methods","authors":"","doi":"10.1109/cpre.2018.8349784","DOIUrl":"https://doi.org/10.1109/cpre.2018.8349784","url":null,"abstract":"This paper will discuss the differences in types of testing philosophies, test set units and different automated testing software used across different utilities. These differences typically arise due to legacy procedures, economic and scalability reasons and difference in understanding of industry best practices. Utilities have their own ways of commissioning and testing protection relays. Some utilities provide logic diagrams along with protection standards and during the commissioning stage the relay testers are expected to test the internal logic and perform dynamic tests, and end to end tests for the protection scheme. Other utilities require the relay techs to only perform static tests and functional tests in order to put the protection in-service. Utilities use different test sets with various capabilities to perform their commissioning and maintenance tests. This paper will present a detailed analysis of some of these differences and discuss their advantages and disadvantages.","PeriodicalId":285875,"journal":{"name":"2018 71st Annual Conference for Protective Relay Engineers (CPRE)","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126232705","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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