Pub Date : 2015-06-14DOI: 10.1109/PPIC.2015.7165853
E. J. Bartolucci, M. Thiele
It is better than 20-years since the newer cable field-testing methods of Very Low Frequency (VLF), Tan Delta, and field partial discharge testing have been introduced to the field-testing arena. Over time these technologies have matured, spawned a new testing industry, IEEE standards, technical committees, and a plethora of technical papers. How has this affected the cable manufacturer and what is his perspective on this area of field-testing both as an acceptance and maintenance test method? This paper intends to discuss the guidelines established and some of the shortcomings that have been found. Although this paper may review the various standards and testing methods, its focus will be with the VLF test.
{"title":"MV-105 cable - Field acceptance testing - A cable manufacturer's perspective","authors":"E. J. Bartolucci, M. Thiele","doi":"10.1109/PPIC.2015.7165853","DOIUrl":"https://doi.org/10.1109/PPIC.2015.7165853","url":null,"abstract":"It is better than 20-years since the newer cable field-testing methods of Very Low Frequency (VLF), Tan Delta, and field partial discharge testing have been introduced to the field-testing arena. Over time these technologies have matured, spawned a new testing industry, IEEE standards, technical committees, and a plethora of technical papers. How has this affected the cable manufacturer and what is his perspective on this area of field-testing both as an acceptance and maintenance test method? This paper intends to discuss the guidelines established and some of the shortcomings that have been found. Although this paper may review the various standards and testing methods, its focus will be with the VLF test.","PeriodicalId":264800,"journal":{"name":"2014 IEEE Petroleum and Chemical Industry Technical Conference (PCIC)","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116180349","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 : 2014-11-20DOI: 10.1109/PCICON.2014.6961872
H. Carl Walther, Richard A. Holub
The technology involved in lubrication of electric motor bearings has been moving steadily forward. The current wording covering the grease(s) qualifying for motors meeting this standard is spelled out in Section 6.1g of the Institute of Electrical and Electronic Engineers Standard 841; “Bearings shall be suitable for, and shipped with, rust-inhibiting grease compatible with polyurea-thickened grease.” There are two significant problems with this statement in today's operating environment: 1) how does one define compatible; and 2) these same polyurea-thickened greases have shortcomings that can be overcome by alternative grease technologies. In fact, polyurea thickeners are now broken into two performance categories, conventional and shear stable, and they may not be compatible with each other. Interestingly enough, some of these new grease technologies may well be compatible with the polyurea thickeners depending on the definition of that same troublesome word - compatible. The goal of this paper is to recommend improvements to update Section 6.1g by illustrating the issues with the above points so that both original equipment manufacturers and users can be confident that they are drawing maximum performance potential from their electric motors while providing flexibility to address significant specific end-use performance requirements.
{"title":"Lubrication of electric motors as defined by IEEE standard 841-2009, shortcomings and potential improvement opportunities","authors":"H. Carl Walther, Richard A. Holub","doi":"10.1109/PCICON.2014.6961872","DOIUrl":"https://doi.org/10.1109/PCICON.2014.6961872","url":null,"abstract":"The technology involved in lubrication of electric motor bearings has been moving steadily forward. The current wording covering the grease(s) qualifying for motors meeting this standard is spelled out in Section 6.1g of the Institute of Electrical and Electronic Engineers Standard 841; “Bearings shall be suitable for, and shipped with, rust-inhibiting grease compatible with polyurea-thickened grease.” There are two significant problems with this statement in today's operating environment: 1) how does one define compatible; and 2) these same polyurea-thickened greases have shortcomings that can be overcome by alternative grease technologies. In fact, polyurea thickeners are now broken into two performance categories, conventional and shear stable, and they may not be compatible with each other. Interestingly enough, some of these new grease technologies may well be compatible with the polyurea thickeners depending on the definition of that same troublesome word - compatible. The goal of this paper is to recommend improvements to update Section 6.1g by illustrating the issues with the above points so that both original equipment manufacturers and users can be confident that they are drawing maximum performance potential from their electric motors while providing flexibility to address significant specific end-use performance requirements.","PeriodicalId":264800,"journal":{"name":"2014 IEEE Petroleum and Chemical Industry Technical Conference (PCIC)","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126167792","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 : 2014-11-20DOI: 10.1109/PCICON.2014.6961887
R. Mistry, Bill Finley, S. Kreitzer, Ryan Queen
This paper will present various case studies of how the rotor or system natural frequencies can be strongly influenced by its external and internal factors and how small variations in these factors can influence the motor vibration at the manufacturer and in the field. Motors constructed to API 541 standards are required to have a rotordynamic lateral natural frequency that is removed from the operating speed by at least 15%. The location of this natural frequency can depend on many factors such as bearing clearance, bearing type, residual unbalance, oil temperature, oil viscosity, and bearing housing stiffness. Depending on the design, some motors are more sensitive to these parameters than others, and small changes in these factors may cause large variances in the motor natural frequency. As a result, small variations in test setup, manufacturing tolerances, or field installations within critical components can cause noticeable differences between the calculated and measured natural frequencies. Variation in motor vibration may also be seen between the motor operating on the manufacturer's test stand and the motor operating in the field. In the field some apparently minor changes on ambient conditions or set up can significantly change the motor vibration. Additionally this paper will propose a worst case calculation method for motor natural frequencies that will provide greater confidence to the end user that the motor will operate successfully in the field before the motor is installed.
{"title":"Influencing factors on motor vibration & rotor critical speed in design, test and field applications","authors":"R. Mistry, Bill Finley, S. Kreitzer, Ryan Queen","doi":"10.1109/PCICON.2014.6961887","DOIUrl":"https://doi.org/10.1109/PCICON.2014.6961887","url":null,"abstract":"This paper will present various case studies of how the rotor or system natural frequencies can be strongly influenced by its external and internal factors and how small variations in these factors can influence the motor vibration at the manufacturer and in the field. Motors constructed to API 541 standards are required to have a rotordynamic lateral natural frequency that is removed from the operating speed by at least 15%. The location of this natural frequency can depend on many factors such as bearing clearance, bearing type, residual unbalance, oil temperature, oil viscosity, and bearing housing stiffness. Depending on the design, some motors are more sensitive to these parameters than others, and small changes in these factors may cause large variances in the motor natural frequency. As a result, small variations in test setup, manufacturing tolerances, or field installations within critical components can cause noticeable differences between the calculated and measured natural frequencies. Variation in motor vibration may also be seen between the motor operating on the manufacturer's test stand and the motor operating in the field. In the field some apparently minor changes on ambient conditions or set up can significantly change the motor vibration. Additionally this paper will propose a worst case calculation method for motor natural frequencies that will provide greater confidence to the end user that the motor will operate successfully in the field before the motor is installed.","PeriodicalId":264800,"journal":{"name":"2014 IEEE Petroleum and Chemical Industry Technical Conference (PCIC)","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123335099","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 : 2014-11-20DOI: 10.1109/PCICON.2014.6961900
P. Sutherland, M. Valdes
Historically, failures of distribution transformers due to transient overvoltage phenomena has led to the development of Resistor-Capacitor snubber circuits for the protection of the transformer and winding insulation. These transients are most often observed when dry-type transformers are close coupled to vacuum switching devices. Typically, snubber circuit design has been specific for the particular application, and complex engineering studies were required. However, the design of a snubber circuit itself may be performed without these detailed studies. If snubber studies are required, the procedures for system modeling and simulation are explained in a step by step manner.
{"title":"Snubber design for transformer protection","authors":"P. Sutherland, M. Valdes","doi":"10.1109/PCICON.2014.6961900","DOIUrl":"https://doi.org/10.1109/PCICON.2014.6961900","url":null,"abstract":"Historically, failures of distribution transformers due to transient overvoltage phenomena has led to the development of Resistor-Capacitor snubber circuits for the protection of the transformer and winding insulation. These transients are most often observed when dry-type transformers are close coupled to vacuum switching devices. Typically, snubber circuit design has been specific for the particular application, and complex engineering studies were required. However, the design of a snubber circuit itself may be performed without these detailed studies. If snubber studies are required, the procedures for system modeling and simulation are explained in a step by step manner.","PeriodicalId":264800,"journal":{"name":"2014 IEEE Petroleum and Chemical Industry Technical Conference (PCIC)","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124315650","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 : 2014-11-20DOI: 10.1109/PCICON.2014.6961891
J. R. White, S. Jamil
Temporary protective grounding serves a critical safety function when working on electrical power systems. Although many field service personnel are well-familiar with the requirements of using temporary protective grounds, many others have only a partial understanding of important aspects of it. This paper reviews the more important aspects of the application of temporary protective grounds, including sizing, order of placement and removal, results of misapplication and common rules for working with temporary protective grounds.
{"title":"Do's and don'ts of personal protective grounding","authors":"J. R. White, S. Jamil","doi":"10.1109/PCICON.2014.6961891","DOIUrl":"https://doi.org/10.1109/PCICON.2014.6961891","url":null,"abstract":"Temporary protective grounding serves a critical safety function when working on electrical power systems. Although many field service personnel are well-familiar with the requirements of using temporary protective grounds, many others have only a partial understanding of important aspects of it. This paper reviews the more important aspects of the application of temporary protective grounds, including sizing, order of placement and removal, results of misapplication and common rules for working with temporary protective grounds.","PeriodicalId":264800,"journal":{"name":"2014 IEEE Petroleum and Chemical Industry Technical Conference (PCIC)","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128170972","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 : 2014-11-20DOI: 10.1109/MIAS.2015.2459115
S. S. Reddy, R. Cosse, M. Wactor, Steve Andre
ANSI/IEEE Medium-voltage circuit breaker ratings have changed in recent years, causing a great deal of confusion over how to properly select a breaker for short-circuit duty. This paper reviews basics of an asymmetrical short-circuit current waveform. It illustrates the effect of the X/R ratio and how the relationship between the dc component and the circuit breaker contact parting time determines the interrupting time of the short-circuit current. Five examples are discussed. The first set examines basic power distribution system applications that illustrate the potential issues of mixing older MVA rated switchgear with new circuit breakers rated using the voltage range factor K=1. The second set examines the complexities that occur when a generator with significant X/R ratio is directly supplying distribution switchgear. Examination of these different conditions is intended to aid equipment users in specifying the correct circuit breaker by identifying the critical factors and conditions affecting the performance of the circuit breaker.
{"title":"Symmetrical, total, and peak; Oh my! - Is current all I use to select my circuit breaker?","authors":"S. S. Reddy, R. Cosse, M. Wactor, Steve Andre","doi":"10.1109/MIAS.2015.2459115","DOIUrl":"https://doi.org/10.1109/MIAS.2015.2459115","url":null,"abstract":"ANSI/IEEE Medium-voltage circuit breaker ratings have changed in recent years, causing a great deal of confusion over how to properly select a breaker for short-circuit duty. This paper reviews basics of an asymmetrical short-circuit current waveform. It illustrates the effect of the X/R ratio and how the relationship between the dc component and the circuit breaker contact parting time determines the interrupting time of the short-circuit current. Five examples are discussed. The first set examines basic power distribution system applications that illustrate the potential issues of mixing older MVA rated switchgear with new circuit breakers rated using the voltage range factor K=1. The second set examines the complexities that occur when a generator with significant X/R ratio is directly supplying distribution switchgear. Examination of these different conditions is intended to aid equipment users in specifying the correct circuit breaker by identifying the critical factors and conditions affecting the performance of the circuit breaker.","PeriodicalId":264800,"journal":{"name":"2014 IEEE Petroleum and Chemical Industry Technical Conference (PCIC)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129295690","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 : 2014-11-20DOI: 10.1109/PCICON.2014.6961909
Peter C. Pietramala, P. Pak, D. Shipp, T. Dionise
Current-limiting reactors are often used in applications where high fault currents encroach or exceed rated fault duties of downstream switchgear. Transient Recovery Voltages (TRV) that develop across the vacuum or SF6 interrupter contacts of the circuit breaker directly in series with the reactor during the interruption of reactor terminal faults can exceed TRV limits published for specific circuit breakers. This situation occurred in an Oil Sands application, where distribution system enhancements and expanded generation to meet process power and steam requirements resulted in overdutied medium voltage switchgear and required installation of a current limiting reactor. Using this case study from the Oil Sand application, this paper will examine transient program modeling techniques associated with reactor-limited fault current interruption and the subsequent TRV response that develops using electromagnetic transients program (EMTP) simulations. These TRV responses, subsequently, are compared to TRV envelopes established by harmonized IEC and IEEE Standards and, where available, manufacturer's breaker lab testing results. In limited cases where the standards or published limits are exceeded, as did occur in this Oil Sands case study, TRV-reduction techniques and the associated practical solutions will be examined. Such practical solutions discussed in the paper include the application of surge capacitors, RC snubber circuits or uprating the breaker to a higher voltage rating.
{"title":"Transient recovery voltage risks and mitigation due to switching for oil sands fault reduction","authors":"Peter C. Pietramala, P. Pak, D. Shipp, T. Dionise","doi":"10.1109/PCICON.2014.6961909","DOIUrl":"https://doi.org/10.1109/PCICON.2014.6961909","url":null,"abstract":"Current-limiting reactors are often used in applications where high fault currents encroach or exceed rated fault duties of downstream switchgear. Transient Recovery Voltages (TRV) that develop across the vacuum or SF6 interrupter contacts of the circuit breaker directly in series with the reactor during the interruption of reactor terminal faults can exceed TRV limits published for specific circuit breakers. This situation occurred in an Oil Sands application, where distribution system enhancements and expanded generation to meet process power and steam requirements resulted in overdutied medium voltage switchgear and required installation of a current limiting reactor. Using this case study from the Oil Sand application, this paper will examine transient program modeling techniques associated with reactor-limited fault current interruption and the subsequent TRV response that develops using electromagnetic transients program (EMTP) simulations. These TRV responses, subsequently, are compared to TRV envelopes established by harmonized IEC and IEEE Standards and, where available, manufacturer's breaker lab testing results. In limited cases where the standards or published limits are exceeded, as did occur in this Oil Sands case study, TRV-reduction techniques and the associated practical solutions will be examined. Such practical solutions discussed in the paper include the application of surge capacitors, RC snubber circuits or uprating the breaker to a higher voltage rating.","PeriodicalId":264800,"journal":{"name":"2014 IEEE Petroleum and Chemical Industry Technical Conference (PCIC)","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130699673","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 : 2014-11-20DOI: 10.1109/PCICON.2014.6961911
A. Bozek, C. Gordon, Niki Phillips
The use of Electrical Hazardous Area Classification drawings as a basis for communicating the degree and extent of explosive hazards within industrial facilities is explored. Existing occupational health and safety regulations are referenced to determine a link between operational activities and the use of electrical hazardous area classification drawings as a tool for hazard assessment and management. How the drawings may be used to improve worker safety in a process facility is discussed. A case study is presented.
{"title":"Electrical Hazardous Area Classification design as a basis for safer operations","authors":"A. Bozek, C. Gordon, Niki Phillips","doi":"10.1109/PCICON.2014.6961911","DOIUrl":"https://doi.org/10.1109/PCICON.2014.6961911","url":null,"abstract":"The use of Electrical Hazardous Area Classification drawings as a basis for communicating the degree and extent of explosive hazards within industrial facilities is explored. Existing occupational health and safety regulations are referenced to determine a link between operational activities and the use of electrical hazardous area classification drawings as a tool for hazard assessment and management. How the drawings may be used to improve worker safety in a process facility is discussed. A case study is presented.","PeriodicalId":264800,"journal":{"name":"2014 IEEE Petroleum and Chemical Industry Technical Conference (PCIC)","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130723033","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 : 2014-11-20DOI: 10.1109/PCICON.2014.6961889
H. Walter, H. Kuemmlee, A. Moehle
This paper discuss the Asynchronous Motor High Speed Concept with massive shaft launched in 2005 after an extensive research period including field testing. This motor is now installed in power ranges between 3.5MW and 15MW and speed ranges between 13.500rpm and 4600rpm with both, Active Magnetic Bearings and Sleeve bearings. This paper will show the first time the complete range concept and the exact measured properties of this motor such as efficiency, power factor, noise date and vibration values as well as application and selection details for this High Speed Motor design. The Gearless High Speed concept offers opportunities in off shore application such as sufficient space and weight reduction for Platforms or FPSO vessels as well as advantages in reliability, availability and service compared to traditional geared solutions or turbine driven arrangements. The future design to meet these upcoming and promising applications will be discussed and introduced. This paper will continue the discussion on High Speed Motor applications in the PCIC forum and add a further step to increase possible applications in Oil & Gas.
{"title":"Ten years high speed motors with massive shaft - experience and outlook","authors":"H. Walter, H. Kuemmlee, A. Moehle","doi":"10.1109/PCICON.2014.6961889","DOIUrl":"https://doi.org/10.1109/PCICON.2014.6961889","url":null,"abstract":"This paper discuss the Asynchronous Motor High Speed Concept with massive shaft launched in 2005 after an extensive research period including field testing. This motor is now installed in power ranges between 3.5MW and 15MW and speed ranges between 13.500rpm and 4600rpm with both, Active Magnetic Bearings and Sleeve bearings. This paper will show the first time the complete range concept and the exact measured properties of this motor such as efficiency, power factor, noise date and vibration values as well as application and selection details for this High Speed Motor design. The Gearless High Speed concept offers opportunities in off shore application such as sufficient space and weight reduction for Platforms or FPSO vessels as well as advantages in reliability, availability and service compared to traditional geared solutions or turbine driven arrangements. The future design to meet these upcoming and promising applications will be discussed and introduced. This paper will continue the discussion on High Speed Motor applications in the PCIC forum and add a further step to increase possible applications in Oil & Gas.","PeriodicalId":264800,"journal":{"name":"2014 IEEE Petroleum and Chemical Industry Technical Conference (PCIC)","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126519892","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 : 2014-11-20DOI: 10.1109/PCICON.2014.6961882
L. Sevov, S. Kennedy, R. Paes, P. Ostojic
The current differential protection is the most popular protection for conventional type transformers, providing good fault sensitivity, selectivity and security. This protection however is not commonly used for transformers with non-standard phase shifts, and more specifically for multi-pulse transformers. The main reason for this is not necessarily the cost of protection, but mostly the inability of many transformer differential protective relays, to compensate non-standard phase shifts without adding specially connected interposing CTs for external phase compensation. This paper presents a new economic way of directly applying differential protection, without the need of interposing CTs.Applying differential protection to protect conventional type power transformers with “standard” phase shifts (multiples of 30° deg.), is relatively simple. However, applying this protection for transformers with non-standard phase shifts requires more thoughts for the protection engineer. This includes a selection of protective device to support such applications, whether or not interposing CTs would be needed, relay connections, computation of winding currents, phase angles per winding and whether or not the windings have grounding with the zone of protection. The paper provides essential knowledge on applying transformer differential protection for medium voltage MV pulse transformer connected to AC drives. Current transformers and relay connections, as well as computation of current differential settings for transformers with standard and non-standard phase shift are covered. The paper is supported by Real Time Digital Simulation (RTDS) tests showing the fault detection sensitivity, dependability and security of the protection.
{"title":"Differential protection for medium voltage pulse transformers","authors":"L. Sevov, S. Kennedy, R. Paes, P. Ostojic","doi":"10.1109/PCICON.2014.6961882","DOIUrl":"https://doi.org/10.1109/PCICON.2014.6961882","url":null,"abstract":"The current differential protection is the most popular protection for conventional type transformers, providing good fault sensitivity, selectivity and security. This protection however is not commonly used for transformers with non-standard phase shifts, and more specifically for multi-pulse transformers. The main reason for this is not necessarily the cost of protection, but mostly the inability of many transformer differential protective relays, to compensate non-standard phase shifts without adding specially connected interposing CTs for external phase compensation. This paper presents a new economic way of directly applying differential protection, without the need of interposing CTs.Applying differential protection to protect conventional type power transformers with “standard” phase shifts (multiples of 30° deg.), is relatively simple. However, applying this protection for transformers with non-standard phase shifts requires more thoughts for the protection engineer. This includes a selection of protective device to support such applications, whether or not interposing CTs would be needed, relay connections, computation of winding currents, phase angles per winding and whether or not the windings have grounding with the zone of protection. The paper provides essential knowledge on applying transformer differential protection for medium voltage MV pulse transformer connected to AC drives. Current transformers and relay connections, as well as computation of current differential settings for transformers with standard and non-standard phase shift are covered. The paper is supported by Real Time Digital Simulation (RTDS) tests showing the fault detection sensitivity, dependability and security of the protection.","PeriodicalId":264800,"journal":{"name":"2014 IEEE Petroleum and Chemical Industry Technical Conference (PCIC)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129867742","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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