The coordination procedure is carried out according to the flowchart shown in fig. Realizing that 85 and 86 are the coil pins, these pins will be transferring the current through the coil. It consists of a set of input terminals for a single or multiple control signals, and a set of operating contact terminals. To make sure of correct relay operation, apply the rated voltage to the relay coil. Relays a relay is an electrical switch that uses an electromagnetic solenoid to control the position of a mechanical power contactor. Also, based on the construction, these relays are classified as hermetic, sealed and opentype relays. Numerical protective relays are sampled data systems, so the sampling block in the figure denotes the capture of instantaneous samples of the phase quantities. In this article, an overcurrent relay is designed based on fuzzy logic control to improve the overall performance of the relay. The principle of relay logic is based on relays which energize and deenergize associated contacts. Based on the dimensions, relays are differentiated as micro, miniature, subminiature and miniature relays.
Compact, slim design use of highperformance flat electromagnetic design achieves 10. A mercury relay is a relay that uses mercury as the switching element. In the event of a fault, protective relays protect electrical systems, equipment, and people from serious damage and injury. These relays assist in the control of air conditioning, heating or refrigeration system compressor motors. Understanding relays page 6 autoshop, all rights reserved. Relay type m15 m15 r1r2 m25 rmi 210 rmi 45 rcp dimensions height length width 15 x 29 x 10 15. In utility and industrial electric power transmission and distribution systems, a digital protective relay is a computerbased system with softwarebased protection algorithms for the detection of electrical faults. Please verify all wire colors and diagrams before applying any information.
They use microcontroller with a software based protection algorithm for the electrical fault detection. The three smaller relays on the bottom row are called signal relays, meaning their contacts are rated for less than 2 amps of. Relays are quite common in home appliances where there is an electronic control turning on something like a motor or a light. How relays work relay diagrams, relay definitions and. Overcurrent relay setting model for effective substation relay coordination international organization of scientific research 27 p a g e associated with temperature rise of the equipment whose permissible limit is based on insulation class and material problems.
A relays mechanical life is relatively long, offering up to 1,000,000 operations. Types of protection relays are mainly based on their characteristic, logic, on actuating parameter and operation mechanism. Solid state dimmers and relays square and round pin from 5 to 30a phase fail relays slim line and ultra slim relays heavy duty relays solid state relays zero crossing turn on. Although most relays are labeled at the bottom, you can always find the 30 pin set perpendicular to pins 87 and 87a for easy identification to the power source. The outstanding performance of our relays is the result of careful design considerations and our complete commitment to quality. Undervoltage or complete loss of voltage on the armature circuit of ac motors and. Microprocessorbased distribution relay applications schweitzer. Once contacts burn out, the relays contacts or the entire relay has to be replaced. Rebirth of negativesequence quantities in protective. A complete dc voltage is best for the coil power to make sure of stable relay operation.
As a result, the relay is capable of performing complex digital. Relays 679 7 r e l a y s t oll free 18005265376 2037 f ax 20371862. Relay based identification of systems bajarangbali and somanath majhi abstract in this paper, describing functions df of relay with hysteresis is used for identification of systems. Load current is based on the correct heatsink being used. The life number of operations can be estimated from the switching voltage and switching current. They use microcontroller with a software based protection algorithm for. Fundamentals of relay technology application note 1 fundamentals of relay technology electromechanical relays are us ed as interface modules between the process io devices, on the one hand, and the openloopclosedloop control and signaling equipment, on the other, for level and power adjustment purposes.
Microprocessorbased distribution relay applications. To implement the procedure, the microgrid system is first assumed as radial network without dg and it is protected by oc relay with inverse. Microprocessor based distribution relays contribute to improved reliability and reduced costs on electric power systems. Microprocessorbased protection devices, relay protection, reliabi lity, ad converter, central processor, watchdog timer. Intelligent over current relays based on interval type 2 fuzzy logic approach conference paper pdf available july 2012 with 178 reads how we measure reads. Relays are classified into several types based on their functionality and application they are implemented for. Relays respond to one or more electrical quantities like voltage or current such that they open or close the contacts or circuits. Jun 08, 2019 based on of logic the protection relay can be categorized asdifferential. Secondly, the implementation of such relays could deter the high investment cost of microprocessorbased relays. Contactors and relays contactor relays eaton wiring manual 0611 53 55 the system and the standard european standard en 50011 terminal markings, distinctive numbers and reference letters for certain contactor relays has a direct bearing on the use and application of the modular system. The switch may have any number of contacts in multiple contact forms, such as make contacts, break contacts, or combinations thereof relays are used where it is necessary to control a circuit by an.
The over current relay problem analysis is done conventionally by timecurrent curves. Using a relay also allows the use of smaller gauge wire to the switch as well. Relays without contacts are not included in this technical guide. Describing function analysis is widely adopted in relay feedbackbased identification methods because of the ease of computation involved and the general usefulness. Secondly, the implementation of such relays could deter the high investment cost of microprocessor based relays. Coordination of overcurrent, directional and differential.
A digital filter based on fourier techniques calculates the fundamental component from the samples captured in the memory of the device. A relay is a switching device as it works to isolate or change the state of an electric circuit from one state to another. Microprocessorbased distribution relays provide technical improvements and cost savings in several ways. The basic element in overcurent protection is the overcurrent relays. 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. Also, relays are the best way for galvanic insulation between high and low voltage portions of a circuit. Most relays are encased in a plastic or metal housing to keep the moving parts free from outside interference and dust see figure 21. Any user assumes the entire risk as to the accuracy and use of this information.
Types of electrical protection relays or protective relays. A relay is an electrical switch that uses an electromagnet to move the switch from the off to on position instead of a person moving the switch. All our s relays are based on this balanced armature mechanism, which is able to further provide many other characteristics. The global line of potential relays are superior in both price and performance.
A communications based protection scheme where high speed. The relays also provide protection for bus faults, breaker failure, and highside transformer blown fuse detection at no or minimal additional cost. They are used where contact erosion would be a problem. They are also common in cars, where the 12v supply voltage means that just about everything needs a large amount of current. Flatvertical type high power bifurcated contact nc relays 4 form c flat type 2 form c flat type 4 form c slim type pc board 2 form c slim type pc board features 1. Pdf intelligent over current relays based on interval. In later model cars, manufacturers have started combining relay panels into the fuse box to.
These classifications include electromagnetic, solid state, high voltage, thermal relays, and so on. Their purpose is to control an event based on time. Implementation of solid state relays for power system. Microprocessor based distribution relays provide technical improvements and cost savings in several ways. Relays 633 7 r e l a y s t oll free 18005265376 2037 f ax 20371862. Also used in automatic throwover equipments application motor running. Electromechanical relays had no significant drawbacks in their protection functions, but the additional features offered by the microprocessor technologies. In 32, the authors have presented a new approach for over current relay problem analysis based on. A solenoid is similar to a motor because it uses a magnetic field to produce physical movement of the solenoid cylinderbut instead of spinning like a motor output shaft, the. Relays 7229 typeicr page 1 phasesequence and undervoltag relays dec. Therefore, this document is intended to describe about a few basic types of relays that are popularly used in typical loadcontrol. Pr512 microprocessorbased selfsupplied protection relays. Working of relayshow relay works,basics,design,construction. Relays are essential for automation systems and for controlling loads.
High sensitivity and reliability provided by 4gap balanced armature mechanism as a polarized balanced armature, the s relay armature itself has two permanent magnets. Thus various advantages of microprocessor based relay are. Actually, a relay is nothing but a combination of one or more open or closed contacts. Evaluation of dsp based numerical relay for overcurrent. All information on this site is provided as is without any warranty of any kind, either expressed or implied, including but not limited to fitness for a particular use. Semiconductor elements transmit and cut the signal or power and contacts are used to supply the power for the relay. Fundamentals of microprocessor based protective relays suhag patel, p.
Operation ensured even with the primary circuit with singlephase power supply. Overcurrent relay setting model for effective substation. The program can handle the online calculations and make the decision accordingly. The new relays deliver a host of benefits, including increased system reliability, improved control, event recording and reporting capabilities, reduced maintenance, simplified regulatory compliance, enhanced communication, arc flash mitigation, and improved protection. Mechanical life is the number of operations openings and closings a contact can perform without electrical current. Here you can see a variety of relays in small to large sizes. Protective relays, associated communication systems, voltage and current sensing devices. Describing function analysis is widely adopted in relay feedback based identification methods because of the ease of computation involved and the general usefulness. Relay logic is the predecessor of ladder logic, which is commonly used in programmable logic controllers. Dec 28, 2015 fundamentals of microprocessor based relays 1. Microprocessor based relays, also called digital relays, have a proven track record of reliability, with over 100,000 relay years of field experience.
The advantage is that a relay is normally cheaper and easier to replace than a switch. It takes a relatively small amount of power to turn on a relay but the relay can control something that draws much more power. Relays typeicr page phasesequence and undervoltag relays com. Furthermore, depending on the load operating range, relays are of micro, low, intermediate and highpower types. Some are even rated by the number of times they will close a circuit before burning out common relays are usually rated to 100,000 operations. Numerical relays or digital relays are designed to carry out protection function of various electrical equipments such as generator, transformer, transmission lines, motor etc. Hybrid relays are a combination of the best of both relays with contacts and relays without contacts. Such relays are also termed as microprocessor type protective relays.
Implementation of solid state relays for power system protection. The processing of numerical relays using dsp is also optimized for realtime signal processing applications 1. Types of relays in this article, the different types of relays like overload protection relay, solid state relay, solid state contactor relay, buchholz relay, mercury wetted relay and. Based on actuating parameter the protection relay can be categorized as. Pdf intelligent over current relays based on interval type. Relay design id relays are either normally open or normally closed. Based on operation mechanism protection relay can be categorized as electromagnetic relay, static relay and mechanical relay. Micro51 microprocessorbased overcurrent relays for phase and ground. A digital protective relay may also be called a numeric protective relay. Miniature power relays miniature size 15 mm high pcb mounting monostable or bistable versions 4 kv 8 mm insulation switching capacity 8 a 250 vac dc coils.
They are functional replacements for electromechanical protective relays and may include many. One improvement is the use of programmable logic to reduce and simplify wiring. Another important advantage of the microprocessor based relay is that a microprocessor unit can perform the retransmission operation of several systems. In electrical engineering, a protective relay is a relay device designed to trip a circuit breaker. A relay is used to control the air conditioner in your home. When using a power supply containing a ripple voltage, suppress the ripple factor within 5%.