Pub Date : 2006-04-04DOI: 10.1109/CPRE.2006.1638695
B. Kasztenny
Transformer inrush currents are known to cause problems for sensitive protection functions applied to a power transformer itself, or in a near vicinity of a transformer. This paper reviews impact of transformer inrush currents on four protection functions. For each category the problem is reviewed and quantified, and practical solutions are presented. First, an impact of inrush currents combined with CT saturation on restricted ground fault (RGF) protection is analyzed. Second, the impact of inrush currents of a step-up transformer on generator protection is presented. Third, impact of the combination of inrush currents and saturated CTs on sensitive ground overcurrent protection is addressed. Fourth, distance zones, if set too far-as compared with the amount of inrush current-could pickup spuriously when energizing a large power transformer is analysed. The paper delivers analysis of the above phenomena and provides practical application guidelines regarding settings and scheme logic.
{"title":"Impact of transformer inrush currents on sensitive protection functions How to configure adjacent relays to avoid nuisance tripping?","authors":"B. Kasztenny","doi":"10.1109/CPRE.2006.1638695","DOIUrl":"https://doi.org/10.1109/CPRE.2006.1638695","url":null,"abstract":"Transformer inrush currents are known to cause problems for sensitive protection functions applied to a power transformer itself, or in a near vicinity of a transformer. This paper reviews impact of transformer inrush currents on four protection functions. For each category the problem is reviewed and quantified, and practical solutions are presented. First, an impact of inrush currents combined with CT saturation on restricted ground fault (RGF) protection is analyzed. Second, the impact of inrush currents of a step-up transformer on generator protection is presented. Third, impact of the combination of inrush currents and saturated CTs on sensitive ground overcurrent protection is addressed. Fourth, distance zones, if set too far-as compared with the amount of inrush current-could pickup spuriously when energizing a large power transformer is analysed. The paper delivers analysis of the above phenomena and provides practical application guidelines regarding settings and scheme logic.","PeriodicalId":125883,"journal":{"name":"59th Annual Conference for Protective Relay Engineers, 2006.","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122669698","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 : 2006-04-04DOI: 10.1109/CPRE.2006.1638703
J. Horak
This paper reviews the basic equations for ground loop current flow, including showing how neutral wires are included in the equations, then showing how this impedance is transformed from an ABC domain impedance to the 012 domain impedance. A side benefit of the approach taken is that the paper shows how one calculates the sequence impedances of untransposed power lines, including calculation of the off-diagonal (mutual) elements of the sequence component 012 domain impedances. The paper also addresses the calculation of mutual impedances between two parallel lines.
{"title":"Zero sequence impedance of overhead transmission lines","authors":"J. Horak","doi":"10.1109/CPRE.2006.1638703","DOIUrl":"https://doi.org/10.1109/CPRE.2006.1638703","url":null,"abstract":"This paper reviews the basic equations for ground loop current flow, including showing how neutral wires are included in the equations, then showing how this impedance is transformed from an ABC domain impedance to the 012 domain impedance. A side benefit of the approach taken is that the paper shows how one calculates the sequence impedances of untransposed power lines, including calculation of the off-diagonal (mutual) elements of the sequence component 012 domain impedances. The paper also addresses the calculation of mutual impedances between two parallel lines.","PeriodicalId":125883,"journal":{"name":"59th Annual Conference for Protective Relay Engineers, 2006.","volume":"533 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127059921","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 : 2006-04-04DOI: 10.1109/CPRE.2006.1638699
C. Mozina
This paper analyzes the motor bus transfer (MBT) issue and developing schemes to accomplish transfer that promote process continuity while causing no damage to the motors or the loads. An important value to decide the viability of MBT is the resultant volts per hertz (V/Hz). The resultant V/Hz issue is exacerbated when the phase angle difference increases and the voltage difference increases. Several methods have been proposed and discussed here
{"title":"Automatic high-speed motor bus transfer at industrial facilities and power plants-theory and application","authors":"C. Mozina","doi":"10.1109/CPRE.2006.1638699","DOIUrl":"https://doi.org/10.1109/CPRE.2006.1638699","url":null,"abstract":"This paper analyzes the motor bus transfer (MBT) issue and developing schemes to accomplish transfer that promote process continuity while causing no damage to the motors or the loads. An important value to decide the viability of MBT is the resultant volts per hertz (V/Hz). The resultant V/Hz issue is exacerbated when the phase angle difference increases and the voltage difference increases. Several methods have been proposed and discussed here","PeriodicalId":125883,"journal":{"name":"59th Annual Conference for Protective Relay Engineers, 2006.","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131393784","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 : 2006-04-04DOI: 10.1109/CPRE.2006.1638702
S. Zocholl
This paper shows the consequences of low accuracy ratings and analyzes the relay response for fault currents in the range of 25 kA to 50 kA, using the CT accuracy rating from the relay data acquisition. To ensure proper relaying performance, the user should make a careful analysis of CT performance considering the relaying requirements for the specific short circuit current and the secondary circuit impedances. The careful analysis of CT performance for high magnitude offset fault requires computer simulation of the relay, as well as the CT, and cannot be carried out by manual calculation.
{"title":"Standard CT accuracy ratings in metal-clad switchgear","authors":"S. Zocholl","doi":"10.1109/CPRE.2006.1638702","DOIUrl":"https://doi.org/10.1109/CPRE.2006.1638702","url":null,"abstract":"This paper shows the consequences of low accuracy ratings and analyzes the relay response for fault currents in the range of 25 kA to 50 kA, using the CT accuracy rating from the relay data acquisition. To ensure proper relaying performance, the user should make a careful analysis of CT performance considering the relaying requirements for the specific short circuit current and the secondary circuit impedances. The careful analysis of CT performance for high magnitude offset fault requires computer simulation of the relay, as well as the CT, and cannot be carried out by manual calculation.","PeriodicalId":125883,"journal":{"name":"59th Annual Conference for Protective Relay Engineers, 2006.","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126598654","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 : 2006-03-14DOI: 10.1109/PSAMP.2006.285385
Joe Mooney, Normann Fischer
Power swing detection on transmission systems is becoming more critical. Traditionally, setting relays for power swing blocking (PSB) or power swing tripping applications has been very complex and time consuming. In many cases, the settings are not correct, which is discovered when the relay operates incorrectly. This paper provides the reader with practical setting and application guidelines for traditional impedance-based PSB schemes. It shows how to set a PSB scheme without stability studies. Highlighted are some problem areas when setting and applying power swing detection elements. Application of these setting guidelines will be demonstrated using a power system modeled on a real-time digital simulator
{"title":"Application guidelines for power swing detection on transmission systems","authors":"Joe Mooney, Normann Fischer","doi":"10.1109/PSAMP.2006.285385","DOIUrl":"https://doi.org/10.1109/PSAMP.2006.285385","url":null,"abstract":"Power swing detection on transmission systems is becoming more critical. Traditionally, setting relays for power swing blocking (PSB) or power swing tripping applications has been very complex and time consuming. In many cases, the settings are not correct, which is discovered when the relay operates incorrectly. This paper provides the reader with practical setting and application guidelines for traditional impedance-based PSB schemes. It shows how to set a PSB scheme without stability studies. Highlighted are some problem areas when setting and applying power swing detection elements. Application of these setting guidelines will be demonstrated using a power system modeled on a real-time digital simulator","PeriodicalId":125883,"journal":{"name":"59th Annual Conference for Protective Relay Engineers, 2006.","volume":"63 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133705250","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 : 2006-03-14DOI: 10.1109/PSAMP.2006.285402
Demetrios A. Tziouvaras
High-voltage underground AC cables have significantly different electrical characteristics than overhead transmission lines. The cable sheath or shield grounding method has a major impact on the zero-sequence impedance of underground cables. Understanding how the underground cable grounding method affects the series sequence impedances is very fundamental to underground cable protection. In the paper we briefly discuss the types of underground cables, their bonding and grounding methods, and the fundamental differences between overhead transmission lines and cable electrical characteristics. Finally we discuss the application of short-circuit protection for high-voltage AC cables
{"title":"Protection of High-Voltage AC Cables","authors":"Demetrios A. Tziouvaras","doi":"10.1109/PSAMP.2006.285402","DOIUrl":"https://doi.org/10.1109/PSAMP.2006.285402","url":null,"abstract":"High-voltage underground AC cables have significantly different electrical characteristics than overhead transmission lines. The cable sheath or shield grounding method has a major impact on the zero-sequence impedance of underground cables. Understanding how the underground cable grounding method affects the series sequence impedances is very fundamental to underground cable protection. In the paper we briefly discuss the types of underground cables, their bonding and grounding methods, and the fundamental differences between overhead transmission lines and cable electrical characteristics. Finally we discuss the application of short-circuit protection for high-voltage AC cables","PeriodicalId":125883,"journal":{"name":"59th Annual Conference for Protective Relay Engineers, 2006.","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114348370","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 : 2006-03-14DOI: 10.1109/PSAMP.2006.285389
C. Mozina
Recent misoperations of generation protection during major system disturbances have highlighted the need for better coordination of generator protection with generator capability, generator automatic voltage regulator (AVR) control and transmission system protection. This paper discusses in detail the important role that the generator AVR plays during major system disturbances. This paper provides practical guidance on proper coordination of generator protection and generator control to enhance security and system stability
{"title":"Power plant protection and control strategies for blackout avoidance","authors":"C. Mozina","doi":"10.1109/PSAMP.2006.285389","DOIUrl":"https://doi.org/10.1109/PSAMP.2006.285389","url":null,"abstract":"Recent misoperations of generation protection during major system disturbances have highlighted the need for better coordination of generator protection with generator capability, generator automatic voltage regulator (AVR) control and transmission system protection. This paper discusses in detail the important role that the generator AVR plays during major system disturbances. This paper provides practical guidance on proper coordination of generator protection and generator control to enhance security and system stability","PeriodicalId":125883,"journal":{"name":"59th Annual Conference for Protective Relay Engineers, 2006.","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124794483","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.2006.1638705
S. Ward, J. Brien, T. Dahlin
Communications channels and channel devices for pilot relaying channels traditionally reside in the relay engineers' domain. Today, many conventional communication channels are being replaced by digital communications networks, which are governed by other departments in the utility. The use of these channels for relaying requires the protective relay engineers to have a working knowledge of digital communications. Many relay engineers are responsible for specifying and/or designing protection schemes that include pilot communication channels. Some protection engineers have little expertise in the area of communications making it difficult to select or specify an acceptable criterion for a reliable channel in terms that are understood by the communications engineers. This paper will look at how one utility evaluated their options for pilot relaying communications channels. It will cover their selection criteria and the qualities they require in the products they use. It will address reliability concerns from substation environment to delay characteristics of communications equipment. The paper is deigned to enlighten the protective relay engineer in the area of communications as applied to protective relaying and the considerations one utility used to evaluate their choices
{"title":"Selection of pilot relaying communication channels-a case study","authors":"S. Ward, J. Brien, T. Dahlin","doi":"10.1109/CPRE.2006.1638705","DOIUrl":"https://doi.org/10.1109/CPRE.2006.1638705","url":null,"abstract":"Communications channels and channel devices for pilot relaying channels traditionally reside in the relay engineers' domain. Today, many conventional communication channels are being replaced by digital communications networks, which are governed by other departments in the utility. The use of these channels for relaying requires the protective relay engineers to have a working knowledge of digital communications. Many relay engineers are responsible for specifying and/or designing protection schemes that include pilot communication channels. Some protection engineers have little expertise in the area of communications making it difficult to select or specify an acceptable criterion for a reliable channel in terms that are understood by the communications engineers. This paper will look at how one utility evaluated their options for pilot relaying communications channels. It will cover their selection criteria and the qualities they require in the products they use. It will address reliability concerns from substation environment to delay characteristics of communications equipment. The paper is deigned to enlighten the protective relay engineer in the area of communications as applied to protective relaying and the considerations one utility used to evaluate their choices","PeriodicalId":125883,"journal":{"name":"59th Annual Conference for Protective Relay Engineers, 2006.","volume":"8 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":"128075264","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.2006.1638697
G. Hataway, T. Warren, C. Stephens
Traditionally, when a permanent fault occurs on a radial distribution line, all load located downline from the protecting device is lost until sectionalizing and network reconfiguration can be done either locally, by personnel responding to the event, or remotely, by a dispatcher (if SCADA is present). In many instances, a substantial amount of load may be lost and a significant number of customers may be impacted until sectionalizing is performed. With much emphasis now being placed on reliability, there is a need to automate sectionalizing and network reconfiguration to speed up service restoration to as many customers as possible, in order to minimize the impact of a fault. Recently Coweta-Fayette EMC, an electric cooperative in Newnan, Georgia, near Atlanta, implemented a high-speed automatic network reconfiguration scheme on a distribution circuit to quickly restore service to unfaulted line sections de-energized by the clearing of a permanent fault. The scheme uses intelligent microprocessor recloser controls and a communications channel between adjacent reclosers to quickly reconfigure the distribution network following a fault. This paper examines the implementation of the reconfiguration scheme by the utility. Specific settings and operational details of the scheme are given. Additionally, a review of the operational history highlights the impact the scheme has had on the reliability of the utility's distribution network
{"title":"Implementation of a high-speed distribution network reconfiguration scheme","authors":"G. Hataway, T. Warren, C. Stephens","doi":"10.1109/cpre.2006.1638697","DOIUrl":"https://doi.org/10.1109/cpre.2006.1638697","url":null,"abstract":"Traditionally, when a permanent fault occurs on a radial distribution line, all load located downline from the protecting device is lost until sectionalizing and network reconfiguration can be done either locally, by personnel responding to the event, or remotely, by a dispatcher (if SCADA is present). In many instances, a substantial amount of load may be lost and a significant number of customers may be impacted until sectionalizing is performed. With much emphasis now being placed on reliability, there is a need to automate sectionalizing and network reconfiguration to speed up service restoration to as many customers as possible, in order to minimize the impact of a fault. Recently Coweta-Fayette EMC, an electric cooperative in Newnan, Georgia, near Atlanta, implemented a high-speed automatic network reconfiguration scheme on a distribution circuit to quickly restore service to unfaulted line sections de-energized by the clearing of a permanent fault. The scheme uses intelligent microprocessor recloser controls and a communications channel between adjacent reclosers to quickly reconfigure the distribution network following a fault. This paper examines the implementation of the reconfiguration scheme by the utility. Specific settings and operational details of the scheme are given. Additionally, a review of the operational history highlights the impact the scheme has had on the reliability of the utility's distribution network","PeriodicalId":125883,"journal":{"name":"59th Annual Conference for Protective Relay Engineers, 2006.","volume":"26 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":"125248457","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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