Delay in operation: Easily provided Digital input/Communication module Input Module The Power system operates with analog parameters. A relay is an electro-mechanical operator switch. semiconductors. Electromechanical relays close in 1-3 mSec, and CAN open in < 5mSec. Here, a case study relating to both electromechanical relay and numerical relay will be done and the results are analyzed. the numerical relays are having microprocessor control systems so the heating of equipment is very less compared to mechanical relays. It is smaller in size. Electromechanical Relay makes use of mechanical comparison devices, which cause the main reason for the bulky size of relays. Functions: 1 relay can perform various functions. Required fields are marked *. In the earlier days, different types of relays are used for the electric protection/controlling system. Electromechanical relays are switches that typically are used to control high power electrical devices. Electromechanical relays are used in many of today's electrical machines when it is vital to control a circuit, either with a low power signal or when multiple circuits must be controlled by one single signal. There are multiple advantages using numerical relays. and mechanical relay required more electrical wiring but numerical relay required very less wiring. the numerical relay having compact size compared to electro mechanical relays, the electro mechanical relays having lot of components, including flag systems. The IEEE defines protective relays as: “relays whose function is to detect defective lines or apparatus or other power system conditions of an abnormal or dangerous nature and to initiate appropriate control circuit action ”. Advantages and Disadvantages of Electro-Mechanical Relays The VA burden of these relays is higher than static and numerical relays. An EMR may be able to respond hundreds of times per minute, but an SSR is capable of switching thousands of times per minute with no chattering or bounce. The other physical quantities like heat temperature etc. 1 relay can perform only 1 function. This is help to find natural & duration fault. 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. Advantages of Static Relay. Memory 4. With static relays, tripping time of ½ cycle or even less can be obtained. Which of the following is not an advantage of solid state relays over electromechanical relays. Hence there is no mechanical noise. Traditional electromechanical and static protection relays offers single-function and single characteristics. Relays detect and locate faults by measuring electrical quantities in the power system which are different during normal and intolerable conditions. The disadvantages of a conventional electromechanical relay are overcome by using micro controller for realizing the operation of the relays. The microprocessor based relays have minimum burden on the instrument transformers. Multi Function Capability. a power switching solution that can be used to allocate power without manually opening and closing the switch it is having great sensitivity and good pickup ratio. Relays are used to switch starting coils in contactors and motor starters, heating elements, pilot lights, audible alarms, and some small motors (less than 1/8, HP). 3. What’s the Difference Between AC and DC Electric Shocks? Advantages of Numerical Relays: Numerical relay consists of many functions in one relay thus replace many traditional relays with one. the numerical relay is having microprocessor control system so it can be easily adjust the required characteristics needed for the equipments. At System Protection we do Retrofitting of Electromechanical Relays with Numerical relays with complete wiring and Testing. Keywords-Electromechanical relay, numerical relay, Local breaker backup, Bus bar protection, Goose The relay manufacturer's use three groupings: electro-mechanical, static, and numeric. but now a days the advance numerical relays are coming and single relay having multiple protections. difference between squirrel cage and slip ring induction motor, What is transistor & How transistor working, Difference between conductor and insulator, How to get pure sinusoidal AC output from DC input using PWM inverter. how the modern numerical relays are used to overcome the disadvantages of electromechanical relays. One significant advantage of a solid-state SCR or TRIAC relay over an electromechanical device is its natural tendency to open the AC circuit only at a point of zero load current. Helps analysis of faults by recording details of: Electromechanical relay do not have the ability to detect whether the normal condition has been attained once it is activated thus auto resetting is not possible and it has to be done by the operating personnel, while in numerical relay auto resetting is possible. This relay has to be installed straight only and away from magnetic field. Flexibility. the numerical relay is having the microprocessor based control systems so it can be easily communicate with computer or laptop communication system. Benefits or advantages of Solid State Relay. Your email address will not be published. Electromechanical Relay makes use of mechanical comparison devices, which cause the main reason for the... 2. Digital protection can be physically smaller, and almost always requires less panel wiring than equivalent functions implemented using analog technology. Many electronic designs can take advantage of the improved performance of solid-state relays (SSRs) relative to that of electro-mechanical relays (EMRs) that perform the same circuit function. One of the first and simplest advantages is reliability. These relays suffer from the effects of age. The numeric relay can be called as a miniature computer as they both have similar hardware architecture with slight differences. In a digital/numeric relay, many functions are implemented by the microprocessor programming. we will see one by one here. Users can configure relay according to their system requirement. This relay directly with numerical. A significant improvement in the relay reliability is obtained because the use of fewer components results in less interconnections and reduced component failures. Input Module 2. but the mechanical required each relay for each protection and modification also very difficult. Advantages of Numerical relays. how to calculate cable size for electrical works, How to calculate KVAR for capacitor bank design, How to calculate short circuit current for transformer. (1 relay can be used as over current relay, under voltage relay etc.) 4. the advantages of a modern numerical relay over static relay equivalents. A. the numerical relays are good reliability and chances of failure is very less compared to mechanical relays. here we will see what are the advantages using numerical relay over mechanical relay. Learn about some of the advantages that PLC systems have over a relay system. earlier days we are used mechanical relay and also we used individual relay for each protection of the equipment. SEL is all numeric relays. is first converted into the analogue and digital electrical signal and then act as an input for the relay. Following are the benefits or advantages of Solid State Relay: It offers very fast response usually about 1µs ON and 0.5 µs OFF. Fibre optical communication with substation LAN. Electromechanical Relays have traditionally been used in machine tool control, industrial assembly lines, and commercial equipment. This generation of static relays became quickly very popular and found a large place in power sys-tem protection. Today, we will dive into some of the advantages of PLCs. For an electromechanical relay, the amount of voltage and current required to energize the relay coil is. Auto reset: It has been highlighted, how the numerical relay is flexible according to requirement. A variety of protection functions can be accomplished with suitable modifications in … One relay can be used in many ways. There are many advantages that a PLC system holds over a relay system. less susceptibility to damage from voltage and current spikes. 3. the numerical relay is having very less tripping times compared to mechanical relays. Depending on the function of the relay in the system, either one could prove to be the most desirabe. The microprocessor based relay furnishes easy interface with digital communication equipment. One of the significant advantages of a solid state relay over an electromechanical relay is its response time (ability to turn on and turn off). Multilin is, I believe, all numeric relays, while some of GE's historic solid state and electro-mechanical relays are still produced. In many cases a single microprocessor relay provides functions that would take two or more electromechanical devices. Loss of voltage feature helps block the relay in case of momentary/permanent loss of voltage. The high powered analog signals are stepped down with current tran… In the era of electromechanical and solid state relays, any one relay could implement only one or two protective functions, so a complete protection system may have many relays on its panel. 5. Range of operation of electromechanical relays is narrow as compared to numerical relay. It is a hardware switching device to control the electrical circuit by using switching logic. Generally we all are knows relay is used to protect the electrical equipment from abnormal condition. Electromechanical and static relays have fixed wiring and the setting is manual. ... the coil. Relays are less likely to be turned on by transients than solid-state switches. They use one or more digital signal processors (DSP) optimised for real time signal processing, running the mathematical algorithms for the protection functions. These relays require to be calibrated periodically and tested. Advantages of Numerical relays 1. In this paper the advantages of numerical relay, hardware structure of numerical relay, protection function provided by numerical relay for transformers and control & operation of transformer using numerical relay are discussed in Section I to Section XI. The advantages of solid-state relays include the following: • SSRs are typically smaller than EMRs, conserving When this operating current increases, coil energizes the electromagnet. the numerical relays are having simple hardware. whenever the rely is activate the  flag also activated. Relay will show automactlly because it was link with history data. While numerical relay is in compact size and use indication on LCD for relay activation. By combining several functions in one case, numerical relays also save capital cost and maintenance cost over electromechanical relays. benefits, the solid-state relays could be set more precisely (Sachdev et al., 2009). Greater sensitivity and high pickup ratio. the numerical relay can control multiple functions at a time compared to electro mechanical relay having maximum one control per relay. In Electromagnetic relays operating current flows through the coil. What is Alternator? Compact Size. Output module 6. 1. For example, we have the following protections in numerical relays in-built into one relay. so what ever the protection system we want to do activate by simply adding software to the system. As a safety device, my feeling is that they are less likely to fail closed, where the electronic device can short-circuit. Their architecture can look confusing but we can just simplify whole architecture into these major categories 1. There are no physical moving parts involved in the design of solid state relay. A big difference between conventional electromechanical and static relays is how the relays are wired. Consists of … Any one numeric relay may implement one or all of these functions. CPU 3. 36 COST OF NUMERICAL RELAYS Modern numerical protection devices have multiple protection elements and this technique makes the cost of the relay comparable with that of electromechanical and static relays … A variety of protection functions can be accomplished with suitable modifications in the software only either with the same hardware or with slight modifications in the hardware. Electro Mechanical Relay • Generally Electro-Mechanical Relays are separately used for individual Phases • High Set Setting is having different mechanism • It consumes more space in Panels which increases C&R Panel cost Numerical Relay • All Numerical Relays are compact in size • All Protection functions are available in same relay • The Numerical Relay is 20% in size of Electro-Mechanical Relays … can be classified to several types attracted armature moving coil induction thermal advantages of numerical realys flexibility in … The distinction between digital and numerical relays is particular to Protection. Etc. some of the relay like over voltage, over current protection , under voltage protection, earth fault protection. Different types of relay characteristics. And relays are less easily damaged by brief shorts or overloads. Reliability. Flexibility. Your email address will not be published. the numerical relay having compact size compared to electro mechanical relays, the electro mechanical relays having lot of ... 2. Solid state relays use _____ as switching devices. The following are the benefits of static relays. Compact Size. the numerical relay having system stored  each fault records, types of fault, nature of fault, fault timing, fault present duration, etc.. but numerical relay is having LCD to indicate the alarm and relay activation. How Alternator is working? (1 relay can be used as over current only for under voltage we use another relay). Basic hardware is shared between multiple functions, the cost of individual protection functions can be reduced significantly. so it can be easily service. It is possible to provide better matching of protection characteristics since these characteristics are stored in the memory of the microprocessor. SUMMARY For green field projects numerical relays are preferred over electromechanical relay. The relay hardware consists of standard modules resulting in ease of service. The continuing reduction in the cost and size of microprocessors, memory and I/O circuitry leads to a si… the single numerical relay is having multiple protection systems. Numeric relays, on the other hand, are programmable relays where the characteristics and behavior can be programmed. It has very high life time. but mechanical relay is having single characteristics. Many functions previously implemented in separate items of hardware can then be included in a single item. The static relay only gives the response to the electrical signal. Reliability. Sulphur Hexaflouride (SF6) Circuit Breakers. Application of various relays used in the power system network depends upon various factors like the amount of fault current, protection methods, etc. If you also want to replace Electromechanical Relay with Numerical Relay, mail your  requirement me at BDM@systemprotection.in, Case Study - How we saved a Process Plant…, By combining several functions in one case, numerical relays also save capital cost and maintenance cost over electromechanical relays, Separate connection is not required, zero sequence voltages and currents can be derived inside the processor. Availability of fault data and disturbance record. numerical relays relay technology electromechanical relays : mechanical forces causes operation of relay contact in response to a signal. We know that there are different types of relays available like Over Current relays, Distance relays, and Differential relays, etc. Once you activity relay than you didn’t have to check your electrical machinery. there are different types of relay used in electrical field. Numerical relays are natural developments of digital relays due to advances in technology. It uses a flag system for the indication purpose whether the relay has been activated or not. By combining several functions in one case, numerical relays also save capital cost and maintenance cost over electromechanical relays. They then also have a family of multi-function numeric relays. Multiplexer and Analog to digital converter 5. 1. The first numerical relays were released in 1985. Look confusing but we can just simplify whole architecture into these major categories 1 help. Characteristics since these characteristics are stored in the memory of the relay the other hand are! 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