COST COMPARISON OF NUMERICAL RELAY WITH ELECTROMAGNETIC AND STATIC RELAY 39 ATMOSPHERIC ENVIRONMENT A relay is generally suitable for temperature as per IEC 255-6 for storage at –25°C to +70°C, and for operation at –25°C to +55°C. the numerical relay having system stored each fault records, types of fault, nature of fault, fault timing, fault present duration, etc.. Modern electrical protection relays are mainly micro processor based, but still electromagnetic relay holds its place. ✓ Electromagnetic relays are employed for the protection of various a.c.and d.c. ✓ The over or under current and voltage protection of various a.c.and d.c.equipments. Static relays are those relays which do not contain any moving parts. … Functions: 1 relay can perform various functions. (1 relay can be used as over current only for under voltage we use another relay). Your email address will not be published. That means open contacts become closed and closed contacts … Solid State Relay also known as Solid State Switch is an electronic device used for switching the load on and off when the external supply voltage is provided across the input terminals of the device. 11. Electromagnetic Relay Definition: Electromagnetic relays are those relay which operates on the principle of electromagnetic attraction. Static Relay: Digital Relay: Numerical Relay: Technology Standard: 1st generation relays. The VA burden of these relays is higher than static and numerical relays. Easy Expandability. It is possible to obtain higher speed of operation with static relays. • PVC-Permanent Virtual Circuit (Static like leased lines) • SVC-Switched Virtual Circuit (Dynamically established) The figure-1 depicts frame relay network which consists of Frame relay switches between DTEs and DCEs.Each connection is identified using uni… ✓ Relay operation can be affected due to ageing of the components and dust,pollution, ✓ Operation speed for an electromagnetic relays is limited by the mechanical inertia. In addition, SSRs often outperform EMRs in several areas. The construction of the relay is easily affected by the surrounding interference. to obtain output instead of mechanical contacts. Electromagnetic Relay Definition: Electromagnetic relays are those relay which operates on the principle of electromagnetic attraction. Advances in technology have increased their mechanical lifetime but electromechanical relays still do … The working of the relay depends on the electrical components. Compared to the Electromechanical Relay, the Solid Static relay has longer life-span, decreased noise when operates and faster respond speed. Your email address will not be published. Thus, precaution should be taken for avoiding the damages through voltage spikes. Static Relays. No power is required from the switched circuit. Static differential relay • In this relay the two similar input quantities (I or V) are compared. It is very easy to provide electrical isolation between the coil that creates the magnetic field and the switch contacts. It generates waste heat during ON mode. Note: Last points are Disadvantages of static Relays. Comparison of Static and Electromagnetic Relays. Present generation relays. A solid state relay is composed of both static and electromechanical units in which the response is accomplished by the static units. A numerical relay has got several advantages as compared to ordinary electromagnetic relays. The term ‘ static ’ implies that the relay has no moving mechanical parts in it. Since the introduction of solid-state relays some decades ago, the debate over which is better, solid-state relays (SSRs) or electromechanical relays (EMRs), has gone on. Actually, a relay is nothing but a combination of one or more open or closed contacts. The various advantages of static relays are: 1. These are given below: Protection is enhanced due to their complex, multiple protections characteristic. But for multi-functional protection, static relay proves economical. 2nd generation relays. In static relays, the measurement is performed by electronic/magnetic/optical or other components without mechanical motion. In this type of relay, the functions of comparison and measurement are performed by static circuits wherein … Operating Principle: They use principle of electromagnetic principle. ✓ They have the properties such as simple, robust, compact and most reliable. ME device is also subject to the influence of external electromagnetic fields, and to a greater extent than MP device. ✓ The directional feature is absent in electromagnetic relays. the numerical relay having compact size compared to electro mechanical relays, the electro mechanical relays having lot of components, including flag systems. It is more vulnerable to surges and spikes in the current which is switched on output side unlike EM relay. ✓ Requires periodic maintenance and testing unlike static relays. (1 relay can be used as over current relay, under voltage relay etc.) Static relays are costlier, for simple and single function than their equivalent electromechanical counterparts. El. as current technology for many relay applications. ✓ slow operating times and reset can be possible. ✓ Electromagnetic relays have fast operation and fast reset. Some variants can work as low as 1.5V DC unlike Electromagnetic relay which requires at least 3V DC. Hence, the Potential and the Current Transformers should have a higher capacity. Electromagnetic relays are those relays which are operated by electromagnetic action. Moving contacts are present. Over time, however, the solid state relay will gain the edge due to its main advantage: there are no moving parts. Present generation relays. So, No problem of Arcing No needs to replace contacts. It also describes Frame Relay basics. It will take much longer time to be replaced the all electromagnetic relays by micro processor based static relays. relay show similar levels of reliability. Gravitational force can affect the relay. Modern electrical protection relays are mainly micro processor based, but still electromagnetic relay holds its place. It will take much longer time to replace all electromagnetic relays by micro processor based static relays. Advantages and Disadvantages of Electromagnetic Relay, MarX Generator>> High Voltage Pulse Generator, Advantages and Disadvantages of Interconnected Power System, Induction Motor Interview Questions with Answers | Part-1. Resetting also very less time required. 1 relay can perform only 1 function. a power switching solution that can be used to allocate power without manually opening and closing the switch (1 relay can be used as over current only for under voltage we use another relay). Comparison between analog wattmeter and digital wattmeter. It mentions Frame Relay advantages or benefits and Frame Relay disadvantages or drawbacks. Based on operation mechanism protection relay can be categorized as electromagnetic relay, static relay and mechanical relay. These are the main reasons, why the industries are shifting to use PLCs over the relay. Hence any functional characteristics as per the requirement can be obtained by the static relays. Disadvantages Of Electromagnetic Relay ✓ High burden level instrument transformers are required such that CTs and PTs of high burden is required for operating the electromagnetic relays compared to static relays. For The Measurement Or Comparison Of Electrical Quantities. Similar advantages and disadvantages of Microprocessor Based relays. The transistor circuits can perform functions like summation, integration, comparison etc. Introduction to Static Relays: Characteristic Functions of Protection Relay: Characteristic Functions of Protection Relay elements using different operating principles. You can only imagine how much easier it is to troubleshoot the PLC system with multiple outputs versus the relay system with four times the number of wires. Solid state relay or static relay is an electrical relay, in which the response is developed by electrical / magnetic / optical or other components without mechanical movement of components. This is proportional to voltage drop. A relay using combination of both static and electromagnetic units is also called a static relay. Fundamental of electrical, Electrical machine theory, High voltage engineering theory, Electrical protection theory Electrical gadgets and power system theory. PLC has more advanced functions as compared to manual work (hardware relay-base). There are many Advantages, Disadvantages and Application of Electromagnetic Relay which will be mentioned in this article. Electromechanical relays typically have shorter mechanical lifetimes than other types. There will not be much physical work. What is Frame Relay? Fast Resetting. When this operating current increases, coil energizes the electromagnet. Digital / Numerical Relays These all or some specific contacts the relay change their state when actuating parameters are applied to the relay. Disadvantages or demerits: High burden level instrument transformers are required (CTs and PTs of high burden is required for operating the electromagnetic relays compared to static relays) The directional feature is absent in electromagnetic relays Requires periodic maintenance and testing unlike static relays The moving parts are absent. When discussing the advantages and disadvantages of MP device, they often do this in comparison with electromechanical protection devices (EM device). The disadvantages of Electro-mechanical relays are. These relays require to be calibrated periodically and tested. Therefore solid state relays are also called as static relays. Compact Size Electromechanical Relay makes use of mechanical comparison devices, which cause the main reason for the bulky size of relays. This relay has to be installed straight only and away from magnetic field. However, integrating an SSR rather than an EMR may result in an equal or even lower overall cost depending on the particular application, something we will discuss a little later. Static relays were manufactured as semi conductor devices which incorporate transistors, ICs, capacitors, small micro processors etc. Yes, Dc supply is required for level detector, timing circuit etc. Advantages of Numerical relays 1. Static Relays. An electromagnetic relay is a switch that is turned on and off by a magnetic field. PLC is easy to maintain. Electromagnetic induction Static Relays. Comparison of Static and Electromagnetic Relays & Advantage of Static Relays 46. These relays suffer from the effects of age. The static relay is more costly as compared to the electromagnetic relay. In Electromagnetic relays operating current flows through the coil. For integrated protection and monitoring systems programmable microprocessor controlled static relays are preferred. Electromagnetic Relay . Relay can be installed at any location and at any position. The Solid State Relay (Static Relay): History of Relay: The static relay are next generation relays .The Solid Static relays was first introduced in 1960’s. The need for electromagnetic compatibility is also a disadvantage of MP device, which can only be compared with EM device. However, such technology will be completely superseded within the next five years by numerical relays. The static relay has low short-time overload capacity as compared to electromagnetic relays. The Output Signal Is Turned Operated A Tripping Device Which May Be Electromagnetic … ✓ Requires periodic maintenance and testing unlike static relays. These relays are robust and highly reliable. The static instantaneous overcurrent relays can have operating time of as small as 10 or 20 ms while in case of conventional electromagnetic relays it is of the order of 0.1 second. When compared to other relays, electromechanical relays are relatively slow devices -- typical models can switch and settle in 5 to 15 ms. 1 relay can perform various functions. Following are the drawbacks or disadvantages of Solid State Relay: It's cost is very high. The Static Network Is So Designed Them It Gives An Output Signal In The Tripping Direction Whenever A Threshold Conditions Reached. and mechanical relay required more electrical wiring but numerical relay required very less wiring. This is probably due to the fact that so far the overwhelming number of relay protection and automation devices in operation at Russian energy facilities is precisely EM relay protection. 3. When the operating current becomes large, the magnetic field produced by electromagnet is high such that this magnetic field pulls the armature or plunger making the trip circuit contacts to close. Problem like Arcing, Replacement of contacts is necessary. Solid state relay or static relay is an electrical relay, in which the response is developed by electrical / magnetic / optical or other components without mechanical movement of components. To make sure the last statement is correct, it is enough to recall that digital technology is more noise-protected than analog. SSRs employ semiconductor switching elements, such as thyristors, triacs, mosfet and transistors to switch the load current. Solid state relays come with a rather large and perhaps intimidating upfront price tag when compared to an electromechanical relay. A static relay refers to a relay in which there is no moving contacts and response is developed by thermionic valves, transistor or amplifiers. With extra arrangements like dashpot, copper rings etc. The static relays have low short-time overload capacity compared with electromagnetic relays. Relay: Static Relay: Digital Relay: Numerical Relay: Technology Standard: 1st generation relays. In static relays, the sensing is taken out by static circuits consisting of comparators, detectors, filters etc. ✓ These relays are almost instantaneous. A relay output card on a PLC sends out one wire to the output device. It is abbreviated as SSR.. Electromagnetic Relay. However, it is not as robust as the Electromechanical Relay. The term ‘static’ implies that the relay has no moving mechanical parts in it. Operating Principle: They use principle of electromagnetic principle. However, it is not as robust as the Electromechanical Relay. An electromagnetic relay is a switch that is turned on and off by a magnetic field. Advantages of Numerical relays 1. This necessitated providing adequate automatic protection for transformer against possible faults. In this relays transistors … As time passes, the springs and the linkages inside the relay grow weak. SCR's or one Triac). It is very easy to provide electrical isolation between the coil that creates the magnetic field and the switch contacts. The construction of the relay is easily affected by the surrounding interference. This page covers advantages and disadvantages of Frame Relay. The conventional electromagnetic relays use the moving parts such as an armature, disc etc. This relay has to be installed straight only and away from magnetic field. Compared to static relays, digital relays introduce A/D conversion of all measured analogue quantities and use a microprocessor to implement the protection algorithm. In contrast, the solid state relay has good electromagnetic compatibility (EMC). PLC requires less time, less wiring. 12. Additional electromechanical relay units may be employed in output stage as auxiliary relays. 1 relay can perform only 1 function. A protective system is formed by static relays and electromechanical auxiliary relays. It is bound by specific current/voltage characteristics. It is combination of both static and electromagnetic units. Data History. No power is required from the switched circuit. Electromagnetic Relay . No effect of Gravity on operation of static relay. Compared to SSRs, EMRs are more susceptible to physical shock and vibration. The disadvantages of Electro-mechanical relays are. The comparator is usually a rectifier bridge rectifier. Static relays incorporate static components such as solid state devices, magnetic or electric circuits etc. One of the best features that a PLC system has over a traditional relay system is versatility with the programming and easy expandability. ✓ High burden level instrument transformers are required such that CTs and PTs of high burden is required for operating the electromagnetic relays compared to static relays. Mech. 2nd generation relays. It is triggered by brief voltage spikes on the input side unlike electromagnetic relay. These relays suffer from the effects of age. Electromagnetic Relay Working. There is leakage current at the output even if relay is in OFF mode. No moving contacts. Mechanical relays use an electromagnetic coil to open or close the circuit. (1 relay can be used as over current relay, under voltage relay etc.). Electromagnetic relays are those relays which are operated by electromagnetic action. An EMR generates electromagnetic … Hence, the Potential and the Current Transformers should have a higher capacity. Relays standards: NEMA Class A and B relays are specified in the publication, Industrial Control, ICS-1970. STATIC RELAYS A Static Relay Is A Relay Which Uses Solid State Components Like Transistors, Diodes Etc. Present generation relays. It will take much longer time to be replaced the all electromagnetic relays by micro processor based static relays. Hence can be used in vessels ie, ships, aircrafts etc. In this relays transistors and IC’s been used : They use microprocessor. They are contrasted with electromechanical relay, which has moving parts for switching. Unlike, electromechanical relays that have moving parts, solid state relays are static in nature thus have inbuilt components like transistors, diodes, capacitors, etc. Within built software with predefined values: They use microprocessor. This operating speed may be too slow for some applications. When current runs through the input and energizes the coil, it creates a small magnetic field which either pulls the arm of the switch away from the other contact of the switch, or pushes it down to close the switch depending on the how the switch is made. Practically all the relaying device is based on either one or more of … provided that static units accomplish the response. Introduction: The frame relay is used for data transmission at higher speed similar to ISDN.It is packet switchinn technology which operates at layers 1 and 2 ofOSI protocol. Measuring element in a static Relay 45. The magnetic field then uses for opening and closing the switch and for performing the mechanical operation. whenever any internal fault occurs in a transformer, the Buchholz relay at once gives a horn for some time, if the transformer is isolated from the circuit then it stop its sound itself otherwise it trips the circuit by its own tripping mechanism. Compact Size. Static Relay: The term ‘static relay’ is generally referred to a relay incorporating solid state components like transistors, diodes, resistors, capacitors, etc. whenever the rely is activate the flag also activated. If we compare the relay with PLC, PLC systems perform better in terms of work, accuracy. Though instantaneous the operating time of the relay varies with the current. These relays control and interlock starters, contactors, and other devices. The burdens imposed on CTs by these relays are very low compared to Electromagnetic relays. The VA burden of these relays is higher than static and numerical relays. Modern electrical protection relays are mainly micro processor based, but still electromagnetic relay holds its place. ✓ The directional feature is absent in electromagnetic relays. Limitations & Semiconductor Devices used in Static Relays Each topic is complete with diagrams, equations and other forms of graphical representations for better learning and quick understanding. Q: What are the advantages of static relay over electromagnetic relay? These relays require to be calibrated periodically and tested. Introduction: The frame relay is used for data transmission at higher speed similar to ISDN. Electro Mechanical Relay • Memory of previous Fault records, Actual Value of Fault Current, etc. It is a type of a magnetic switch which uses the magnet for creating a magnetic field. Delay in operation: Easily provided ✓ They can be used for both a.c.and d.c.systems for protection of a.c.and d.c. ✓ Electromagnetic relays operating speeds which has the ability to operate in milliseconds. Save my name, email, and website in this browser for the next time I comment. Electromagnetic relays are those relays which are operated by electromagnetic action. Thus they are bulky in size. Further, the orientation of the electromechanical relay relative to the shock or vibration must be considered in designs where physical movement is expected. but numerical relay is having LCD to indicate the alarm and relay activation. And the solid state relay with zero-crossing function can reduce the influence of external interference on SSR, and also reduce the interference signal generated by the solid-state relay itself. Disadvantages or demerits: High burden level instrument transformers are required (CTs and PTs of high burden is required for operating the electromagnetic relays compared to static relays) The directional feature is absent in electromagnetic relays Requires periodic maintenance and testing unlike static relays Electromechanical Relay makes use of mechanical comparison devices, which cause the main reason … Requires periodic maintenance and testing unlike static relays. The performance of static relay is better than electromagnetic relays as they are fast acting and accuracy of measurement is better than electromagnetic relay. Are you looking for comparison of electromagnetic relay vs static relay vs numerical relays ? the numerical relay is having very less tripping times compared to mechanical relays. Advantages of Static Relays. These principles and design criteria determine how well the basic function is performed and how in practice it deviates from the ideal. The relay has less overloading capacity. Let’s compare the two: Disadvantages or demerits: High burden level instrument transformers are required (CTs and PTs of high burden is required for operating the electromagnetic relays compared to static relays) The directional feature is absent in electromagnetic relays. Required fields are marked *. Can damage this relay because electronic components are used. Both of the above factors [factors (5) and (6)] are the design features of the circuit and careful design of static relay circuitry can compensate for these limitations. So before going through detail of protection relay … It is a type of a magnetic switch which uses the magnet for creating a magnetic field. Drawbacks or disadvantages of Solid State Relay. Highly trained personnel are required for their servicing. Present generation relays. And strong electromagnetic interference will even damage the human body. Frame relay establishes connection between DTE and DCE using two modes. ✓ Used as auxiliary relays in the contact systems of protective relays schemes. The comparison and measurement are done by the static circuits thus have no moving parts. The magnetic field then uses for opening and closing the switch and for performing the mechanical operation. o Low power consumption as low as 1mW o No moving contacts; hence associated problems of arcing, contact bounce, erosion, replacement of contacts o No gravity effect on operation of static relays. Advantages of Solid State Relay: Static Relay burden is less than Electromagnetic type of relays. A relay is generally suitable for humidity as per IEC 68-2-3, for enclosure protection IP 52 as per IEC 529, for seismic, shocks and bumps as … The static relay is more costly as compared to the electromagnetic relay. A. Buchholz relay is a device which is used for the protection of transformer from its internal faults, it is a gas based relay. 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Contacts the relay is easily affected by the surrounding interference browser for the next five years by numerical a..., coil energizes the electromagnet detectors, filters etc. ) subject to the shock or vibration be. Protection and monitoring systems programmable microprocessor controlled static relays are those relays which do not contain moving... Output device these are given below: protection is enhanced due to main! ( 2 ea electromechanical relays typically have shorter mechanical lifetimes than other types protection.. Relays which are operated by electromagnetic action only for under voltage we use another relay ) relay weak! Gravity on operation of static relays, electromechanical relays are: 1 require be... 3V DC are operated by electromagnetic action comparison of electromagnetic attraction calibrated periodically tested... For opening and closing the switch and for performing the mechanical operation uses for opening and closing the and... Through voltage spikes on the principle of electromagnetic the disadvantage of static relay compared to electromagnetic relay is perform functions like,... Operation and fast reset to its main advantage: there are no moving mechanical parts it... Principle of electromagnetic relay by a magnetic field and the switch and for performing the mechanical.! Having lot of components, including flag systems life-span, decreased noise when operates and respond... Deviates from the ideal disadvantages and Application of electromagnetic attraction relays come with a rather large perhaps!, small micro processors etc. ) those relay which operates on the principle of attraction... A static relay is used for data transmission at higher speed similar to ISDN external electromagnetic,! Function is performed by electronic/magnetic/optical or other components without mechanical motion DTE and DCE two! Devices -- typical models can switch and for performing the mechanical operation per the requirement can be used as current... ( EMC ) time of the best features that a PLC sends one.