Protective relaying principles and applications 4th edition. Protective relaying philosophy and design guidelines. Choosing between a relay and a contactor isnt really difficult. Relays and contactors use a variety of technologies to switch signals and power connections. To turn things on and off, we need devices that are switchable by the application of a current or voltage. A relay is normally used in appliances below 5kw, while a contactor is preferred when the appliance is heavier. Episode 28 the difference between contactors and relays electromagnetic switches duration. The relay will now use 30% of this itotto derive its actual restraint current, i. They can be used as standalone manual starters or to protect each branch circuit of a group motor installation. Contact of a relay can be used to connect or disconnect the coils of a contactor. There are various types of control relays including machine tool relay, industrial relay and general purpose relay. The main difference between contactors and relays is the loads that they are meant to handle. Directional overcurrent and directional power relays. Epic sealing technology is used f or gigavac part series mx16, automatic disconnect.
Abb advanced feeder protection system ref 550 instruction booklet 7. Faults instrument transformers correlation to drawings other. Since some relays are frequencysensitive, each of the relays operating characteristics vs. Nfz contactor relays withstand short voltage dips and voltage sags semi f470706 compliance between 24. Current carry vs time with 85 c terminal temperature rise 500 mcm 400 mcm. Contactors and contactor relays for railway contactors and. Because of this, relays are often used as a middleman between the electronic circuit and the contactor. Transformer relay protection program life of a transformer.
Sealin unit target target target z 1 z 2 z 3 t 2 t 3 sealin unit tc breaker aux. A contactor joins 2 poles together, without a common circuit between them, while a relay has a common contact that connects to a neutral position. Industrial relay modules and solidstate relays overview easy handling and safe connections weidmullers relay bases are remarkable for their secure connection systems and their ease of use during wiring and installation. Substation automation and protection 7036 snowdrift road.
Jun 18, 2017 relay protection testingfor ge, sel, nari, sifang, siemens, abb etc. They are used in large numbers for the indirect control of motors, valves, clutches and heating equipment. Oo courses hosted by relay manufacturers specific to their relays. Mutual impedance in parallel lines protective relaying and. Oo engineering books written for design engineers, not relay testers. Dc protections ac protections apparatus protective relays common features of the protection philosophy, the protective functions and the fault clearing actions are given. Distancerelay protection testingfor transmission line. Other relay variations include three and five pin relays. The main difference between the contactor and relay is that, contactor is a high power device while relay is a low power device. In ac circuits the arc drawn as contacts open is intrinsically selfextinguishing at the zero crossing.
Get access to premium hvmvlv technical articles, electrical engineering guides, research. Generator protection reg650 ansi application manual. Contactors and relays is a course designed to familiarize participants with the operation and use of magnetic contactors and relays. Pdf this paper presents a procedure and computation of relay protection coordination for a pv power plant connected to the distribution network. This guide focuses on the general approach and specific procedures for testing protective relaying systems that include multiple interacting relay components, auxiliary devices, and power apparatus. Contactor vs relay difference between relay and contactor duration. By design and construction they ensure potential isolation between the actuating. White paper on different types of relays the relay is an automatic protective and switching device which is capable of sensing abnormal conditions in electrical circuits. Methods of testing these elements, settings criterion, diagnosing misoperations will all be in your bag of tools to perform your job with confidence. Also, tools for the system programming and supervision are. Difference between contactor and relay compare the. This comparison summarize characteristics of all protection relay types described in previously published technical articles. Oo testset manufacturer, or automated test software, training focused on how to get their solution to test. Most utilities have a wide variety of test plans and practices.
V5t248 product overview freedom series starters and contactors feature a compact, spacesaving design, using stateoftheart technology and the latest in high strength, impact and temperature resistant insulating materials. The basic principle of operation of the contactor and the relay are the same. Sometimes a special screw unitized screw and spring washer is used in the coupling section of the electromagnetic contactor and thermal overload relay in an. Implementation of a distance relay to protect transmission line l1 3. The transformer can then be disconnected from the system. Contactors and relays are two closely related terms leading to confusions and misinterpretations most of the times. A read is counted each time someone views a publication summary such as the title, abstract, and list of authors, clicks on a figure, or views or downloads the fulltext. Mutual impedance in parallel lines protective relaying and fault location considerations fernando calero, schweitzer engineering laboratories, inc. In general dc contacts have larger contact areas so that they can survive more damage. Some of the more common variations are mentioned below. Volume 5power control products ca033001enjanuary 2017. Contactors are typically built for and used in 3phase applications where a relay is more commonly used in single phase applications. Relay elements in step distance schemes use positivesequence impedance in step distance schemes three relay elements are needed for detecting multiphase or singlephasetoground faults k z.
Take away a sound understanding of all related protective elements such as differential, voltshertz, through fault, etc. Commissioning of protective relay systems karl zimmerman, schweitzer engineering laboratories, inc. Understanding and testing the abb red670 distanceline differential relay figure. This document gives an overview of the hvdc protection system. After completing this course, participants should be able to describe the operating principles of magnetic contactors and relays, and explain how both types of devices are used in electrical systems. Difference between contactor and relay difference between. A directional power relay can be used to limit power flow in a circuit. Transformer relay protection program monday, february 11 thursday, february 14, 2019. These are sometimes called relays or solenoid, motor contactor, battery relay, ev relay, heavy equipment relay, pv relay and special purpose contactor. By design and construction they ensure potential isolation between the actuating circuit and the operating circuit, in the deenergized state, between the contact input and output.
All dil contactor relays have doublebreak contacts. Electrically, we have transistors and integrated circuits. Backup relay x y load l2 load l1 t1 s bus over current backup relay differential relay. Alternating current ac and direct current dc contactors are found in many industrial motors, including many automobiles. Request document 252oct9501r697 enclosed iec starters dline starters and integral selfprotected starters are available.
The contactor relay contacts themselves constitute a considerable safety feature. Note minimum conduct current of auxiliary contactor is dc 17v 5ma. Contactors and relays 5 contactor relays contactor relays contactor relays are often used in control and regulating functions. Ieee guide for protective relay applications to transmission. In dc circuits the arc can be maintained for longer. Features, benefits and functions freedom nema adjustable bimetallic. Understanding and testing the abb red670 distanceline. The three distance measuring elements z 1,z 2 and z. In addition, you can configure the relays as dry contact relays or as 24 vdc output relays. Feeder protection, or more exactly protection for overhead lines and cables, is the most commonly used type of protection. The control relay is one of the oldest type of relay and perhaps the best known. Current carry vs time contactors, high voltage relays. Current splits inside the relay, supplying power to both the control and load circuits.
Overload relay motor damage 12 awg wire damage thermal withstand limit contactor breaking current contactor withstand 30i e 2 crossover point i c 5. L starters with fuse protection nf c or din fuses, type am, contactor and thermal overload relay. In addition to the simplicity which they offer in project engineering, panel building. Topics include the selection of communication systems, redundancy, autoreclosing, ground overcurrent protection, line length and source impedance ratio.
Abstractperforming tests on individual relays is a common practice for relay engineers and technicians. The cmd also monitors the functioning of the internal relay using an additional. Pluggable crossconnection and the extraquick push in connection help you to further reduce wiring times. Pdf easy method for testing transformer differential relays. Pdf the relay protection coordination for photovoltaic. Contactors and contactor relays for railway applications advanced but simple the afb contactors and nfb contactor relays can be installed in any environment including passenger or driver cabins, for main or urban line trains, underground trains or trams circulating frequently in tunnels or underground passages. The relay is usually used in the electrical control circuit, its used to extend the contact capacity of a micro or small relay, so as to drive larger load. Protective relaying philosophy and design guidelines pjm. The electronic circuit provides the power to turn the relay on, which in turn switches a larger voltage source needed to turn on a contactor. These are operated to open or close the load contacts in response to one or more electrical quantities like voltage and current. Pdf files add kmtronic web lan internet relays to your.
This page contains technical data sheet, documents library and links to offering related to this product. The safety cover of magnetic contactor and thermal overload relay is optional. Telemecanique integral selfprotected starters combine. Both of them are electrically operated switches used for control and switching of loads. Control relays are available in numerous configurations. Disclaimer the data, examples and diagrams in this manual are included solely for the concept or product description and are not to be deemed as a statement of guaranteed properties. Relay trip signal from the distance relay 21 to the circuit breaker to protect the transmission line l1 in case of fault rest of the power system figure 4. The different contactors accomplish the same thing, but they do it in different ways, starting with how they are constructed. If the contactor coil is deenergized and the contactor does not drop out, the. As we can see, the fault occurred on 80% of the line ab as seen by relay a. Fsrrm24 remote relay module installation sheet description the fsrrm24 provides five form c relays that you can configure as common relays, zone relays, or as programmable relays to use with fseries fire alarm control panels. Abstractwhen two or more lines are running parallel to each other, mutual impedances between the lines modify the voltage and current profile measured in the protective relays.
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