These relays have been now superseded by the microprocessor based relays or numerical relays. Power system protection part power system protection lecture. Protective relay designs vary with different manufacturers and are constantly changing, especially as solidstate technology impacts this area. Digital protective relaying algorithms and systems an. In our future works more concrete technical solutions and circuit diagrams for starting unit will be developed. Changes to relay protection in response to the problems encountered and other solutions that have been applied are also covered. Application guide for the choice of protective relays. The second issue is the question of the reliability of the software required for digital protective relay systems. Transformer protective relays that are sold worldwide must be able to handle both phasing standards. Kezunovic westinghouse electric corporation, 200 beta drive, pittsburgh, pa 15238 u. January 2021 digital switchgear concepts for mv applications. The advantages and disadvantages of schemes presently being used in protecting distribution lines are examined in this guide. Jul 01, 1981 electric power systems research, 4 1981 167 180 elsevier sequoia s. Identification of problems with the methods used in distribution line protection and the solutions for those problems is included.
The portion of a power system shown by the oneline diagram of fig. Equipment condition for switchgear and circuit breakers. Fig 2 shows the changing hardware and software design content in electronic protective relays. Gurevich 336 the generation of the extremely high voltages on such elements under shortcircuits in the mains we are speaking of power transformers of 110 kv and. Protection of power transformers against geomagnetically. Digital microprocessorbased protection relays dpr are dominating the global market today, essentially pushing all other types of relays out of the picture. However, as the requirement for faster protective relays grows, so does the concern over the poor transient response of some cvts for certain system conditions. Furthermore, it serves as a reference guide for solving application problems. However, the performance of digital relays depends on many factors. Protection relay also called the protective relay is a device designed to trip a breaker when any fault is detected firstly protective relays were electromagnetic devices, counting on coils performing on moving parts to supply detection of abnormal operating situations like overvoltage overcurrent, reverse power flow, over. Relays that use fixed 8 khz timedomain sampling do so for highresolution oscillography and comtrade files. The content is generic and may not be applicable for circumstances or equipment at any. Lessons learned from commissioning protective relaying systems.
Problems and solutions digital microprocessorbased protection relays dpr are dominating the global market today. Oo testset manufacturer, or automated test software, training focused on how to get their solution to test. Power quality disturbances and protective relays core. Motor protection relays protect against damage and downtime caused by problems such as overcurrent, phase loss, voltage unbalance and more. Protective relaying principles and applications solutions. Digital microprocessorbased protection relays dpr are dominating the global market. And yet its challenging endofchapter problems, coverage of the basic mathematical requirements for fault. Selectivity speed reliability stability sensitivity. Jan 20, 2012 commissioning protective relays has changed with the increased use of microprocessor many relays based relays. Being able to handle both these phasing standards has added to the complexity of digital transformer relays. Solidstate and microprocessor relays can respond to a cvt transient due to their high operating. The digital protective relay is a protective relay that uses a microprocessor to analyze power system voltages, currents or other process quantities for the purpose of detection of faults in an electric power system or industrial process system.
Multipointtomultipoint protective relaying signaling using. It includes a parser for comtrade and pqdif formatted records, and demonstrations have been conducted using. For todays digital relays, only 20% of the total design effort involved is for hardware, compared to 80% for the software. Problems of electromagnetic impacts on digital protective relays. Introduction modern trends of relay protection rp development based on the substitution of electromechanic protection relays by digital protective relays dpr preconditioned the emergence of an absolutely new problem, which was not known before. Properly communicating the phase shift introduced by deltawye transformers to a digital relay is the biggest source of. Digital protective relays ebok vladimir gurevich ark bokhandel. For illustration purposes, let us take an example of an overcurrent.
Where does negative phase sequence relay is employed. The first protective relays were electromagnetic devices, relying on coils operating on moving parts to provide detection of abnormal operating conditions such as overcurrent, overvoltage, reverse power flow, overfrequency, and underfrequency. Problems and solutions offers a unique focus on the. Impact of distributed resources on distribution relay.
Contents contents protective relays 497 chapter protective relays 21. The question arises if the microprocessorbased protection device is a relay in the full sense of the word. Key technologies and principles behind protective devices architecture of the modern numerical or microprocessor based relay how to configure the various relays how to apply the modern relays to your distribution network how to assess and manage relay settings typical problems and solutions with modern power system relays. Download file pdf protective relays application guide library zhacaiore. The art and science of protective relaying ge grid solutions. It is important to understand that these different types of relays actually have very similar hardware configurations. Unlike oldfashioned overload relays, modern relays are smart electronic devices that can tell the operator which condition triggered a shutdown. This paper explores new solutions for performance analysis of transmission line protective relays. The goal is to implement better approaches to testing protective relay behavior, better online monitoring of relay operations, and better understanding of the causeeffect analysis of relay operation. Their influence on the protection of the system is based on the type of connections. The protection relay and control product portfolio includes a comprehensive line motor and pump protection relays, arcflash relays, ground fault relays, feeder protection, pump controllers, time delay relays, flashers and tower lighting, and more to minimize electrical safety hazards, limit equipment damage, improve productivity, and safeguard. Introduction to protective relaying electric power. In electrical engineering, a protective relay is a relay device designed to trip a circuit breaker when a fault is detected 4 the first protective relays were electromagnetic devices, relying on coils operating on moving parts to provide detection of abnormal operating conditions such as overcurrent, overvoltage, reverse power flow, overfrequency, and underfrequency. These input devices or instrument transformers provide insulation from the highpower system voltages and reduce the magnitudes to practical secondary levels for the relays.
Role of protective relaying in the smart grid report to the main committee working group c2 of the system protection subcommittee, power system relay committee chairperson. On closer examination it turns out that the microprocessorbased relay is a small computer in. Pdf power system protection lecture notes d manohar. System and protective relays commissioningmodern solutions for protection, control. Protective relays introduction protective relaying is one of the several features of the power system design. Most of the data processing happens in the digital domain.
A digital protective relay may also be called a numeric protective relay. In the proposed system, the resources of the protective and control hardware are pooled. Cyber security issues for protective relays ieee psrc. Morinec3, senior member, ieee abstract a stateoftheart analog microwave system was installed in the cleveland area in the 1950s and 60s for pilot protection of 8 kv transmission lines as the transmission system was. How to test protective relays, 16 ceus this online protective relay testing seminar follows chris werstiuk author of the relay testing handbook as he tests a relay from start to finish. It allows you to download paywalled content for free including pdf downloads for the stuff on elseviers science direct website. Nov, 2014 protective relays using electrical quantities are connected to the power system through current transformer ct or voltage transformer vt.
Received november 17, 1980 summary this paper gives an overview of the digital algorithms and systems for protective. Oo engineering books written for design engineers, not relay testers. The protection of the generators and the interface protection are specifically omitted from this report. These same applications require fast, yet secure protection. The material included is not intended to be a complete presentation of all potential problems and solutions related to this topic. Numerical distance protection relay commissioning and testing. However, the shortcomings of these relays are also obvious. Protective relays have seen widespread use in industrialized power systems since the early twentieth century, with continued technological development. In the years since, we have grown and developed a complete line of products and services for the protection, monitoring, control, automation, and metering of electric power systems. In such a situation, the kalman algorithm is a possible solution. The digital busbar solutions are more affordable and easy to engineer, opening new application opportunities. Numerical distance protection relay commissioning and. In a digital protective relay, the pickup and operation information of protection elements is usually in the form of logic operands. Problems and solutions digital microprocessorbased protection relays dpr are dominating the global market today, essentially pushing all other types.
Fusing is employed where protective relays and circuit breakers are not economically justifiable. An overcurrent relay normally has a current setting multiplier referred to as plug setting ps in razavi 8. The content is generic and may not be applicable for circumstances or equipment at any specific facility. Impact of distributed resources on distribution relay protection. In papathanassiou 7 are presented indicative settings for the interconnection protection relays. Cee have developed the procom range of digital protection relays, which benefits from the above advantages without sacrificing the standalone capability of the classical solid state relays such as the.
While there is already a massive amount of literature documenting the benefits of using digital relays, devices as sophisticated as dpr obviously have faults and drawbacks that need to be understood. Faults instrument transformers correlation to drawings other. The factors affecting the choice of protection are type and rating of equipment, location of the equipment, types of funks, abnormal conditions and cost. Digital microprocessorbased protection relays dpr are dominating the global market today, essentially pushing. Cts can be connected in wye when a digital 87 relay with internal mathematical compensation is used. Thus it is desirable to keep ctvt burdens as low as possible. However, the newer relays also provide many advantages in commissioning, including. We learn from our mistakes to find solutions that work problems and solutions time synchronization for digital fault recorders dfrs phasor. These devices play a vital role in power operations for fields ranging from manufacturing, transportation, and communication to banking and healthcare. One such case of particular importance is bus 87 protection. The key aspects and features of a modern costefficient new phaseaggregated digital busbar protection solution are discussed.
We will start with a brief history of protective relays to compare the different. Problems and solutions offers a unique focus on the problems and disadvantages associated with their use, a crucial aspect that goes. Power system protection part power system protection. Temperature pressure wattmetric type induction cup shaded pole types of relay.
Cee have developed the procom range of digital protection relays, which benefits from the above advantages without sacrificing the standalone capability of the classical solid state relays such as the itg and ttg series. As the capabilities of protective relays have grown in the past few decades, we have seen new solutions and techniques applied to improve the speed, sensitivity. New solutions for improved transmission line protective. Mohammed tawfeeq overcurrent protective relays overcurrent relays overcurrent relaying is the simplest and cheapest type of protection used for protection of lines, transformers, generators and motor. The numerical distance protection relay used is rel 5112. However, protective relaying applications remain the same. The unique protection problem was the direct tapping of two or more lines to feed 836 kv subtransmission stations having low side tied busses while main. Types of relays the main types of protective relays are summaries in the following diagram.
Load sharing relay rrs voltage vector shift voltage frequency relays ufd34, um30a directional over current relay dm33 transformer protection relays md32t, im30t, um30sv auto reclosing relay im30dre. Abb is pleased to provide you with technical information regarding protective relays. In addition to the procom protection relays such as the rms, rmsd, rmsr, imm, gms and dms relays, the procom range also includes the cms digital instrumentation units, ams local plcs. Motor protection relay mm30, mm30w, mpr300 generator protection relays im3gv, mg30, md32g synchronising relays spm21, scm21. We must decide if a ct can supply multiple relays or if separate, designated cts are required for each relay. In electrical engineering, a protective relay is a relay device designed to trip a circuit breaker when a fault is detected. The differentiation between the various types is based on the firmware programming. Pdf application guide for the choice of protective relays.
The practiceof protective relaying has long sought to accurately identify every possible type of fault that could occur in a protected apparatus and to provide the appropriate response. Abb protective relay school webinar series abb is pleased to provide you with technical information regarding protective relays. Sel introduced the worlds first digital relay in 1984, revolutionizing the power protection industry by offering fault locating and other features for a fraction of the cost of earlier systems. Youll learn the basic skills needed to test any digital relay with any modern testset, how to perform each testing step, and why each step is important. Role of protective relaying in the smart grid report to. There are some problems unique to pumps that make it worthwhile to consider a protective relay designed specifically for this application see figure 1. A lowimpedance bus 87 relay can share cts with other devices. Modern costefficient digital busbar protection solutions. Multifunction digital relays have also added a new problem through software. A numerical protection relay solution application report slaa466aseptember 2010revised july 2018 a numerical protection relay solution. Protective relays application guide library zhacaiore. The use of digital multifunction relays and their proper integration into power system is an important element of this process. A digital relaying algorithm for integrated power system. Protection relays, or distant protection relays, as well as other types.
Faults instrument transformers correlation to drawings. Pr protection relay cb circuit breaker equip protected item ct current transformer vt voltage transformer dc aux dc auxiliary supply hmi manmachine interface pcl communications link tr cb trip coil the two primary protective equipment components used in the isolation of faults and abnormalities are circuit breakers, and protective relays. Eliminates problems of saturation and ferroresonance 4. Microprocessorbased digital protection relays now emulate the original devices, as well as providing types of protection and su. This webinar brought to you by the relion product family. On closer examination it turns out that the microprocessorbased relay is a small computer in which the output circuits usually builtin ct or vt. Solutions to common distribution protection challenges. Even the most modern digital protective relays operate on the traditional 125 vdc supply voltage816 rather than 120 vac as is common with other types of industrial controls. The philosophy of protective relaying ge grid solutions. Higher burden leads to problem of ct saturation and inaccuracies in measurements. Problems and solutions offers a unique focus on the problems and disadvantages associated with their use, a crucial aspect that goes largely unexamined. Bookmark file pdf protective relaying theory and applications.
The relay operands are more reliable than scada data because they are more redundant and have less uncertainty than relay trip signals and circuit breaker status signals. Role of protective relaying in the smart grid report to the. Index termscyber security, protective relaying, relay, relaying. Paralleling cts for line current differential applications.
Lessons learned from commissioning protective relaying. Frequency tracking fundamentals, challenges, and solutions. Ariza, phil beaumont, sukuman brahma, craig bryant, j. Safety no possibility of unsafe voltages from open ct secondary circuits 5. Continuous monitoring of protection relay integrity by selfsupervision and autodiagnostics. Attracted armature solid computerized state digital relays plunger type magnetic induction electromagnetic numerical relays magnetic attraction others. As a result, design aspects are not emphasized in this book.
428 526 1364 1024 427 1084 32 1251 574 303 1299 1468 797 87 319 1418 1085 1246 1267 1171 390 894 454 1041 116 150 953 182 231 328 979