The parts are as follows: Spring Electromagnet Additionally, the input signals must be amplitude limited to avoid them exceeding the measurement range, otherwise the waveform is clipped, introducing harmonics. They use one or more digital signal processors (DSP) optimised for real time signal processing, running the mathematical algorithms for the protection functions. Each relay element is in software so with modular hardware the main signal processor can run a vast variety of relay elements. Backup Protection: 3 Nos. Firstly the quantities of interest are determined from the information in the data samples. The introduction of numerical relays replaces some of the issues of previous generations of relays with new ones. A different interface port for the Hot signals (with varying voltages) for the E&M and Static Relays while as a different Communication port for the Soft signals from the Numerical Relays. For faster real time processing and more detailed analysis of waveforms, several DSPs can be run in parallel. No effect of Gravity on operation of static relay. Position of relay: Relay can be installed at any location and at any position. Numerical Relays working explained in this post with the help of a Numerical relay used in industrial applications. Different configurations may require different relay settings to maintain the desired level of network protection. Within built software with predefined values, Induction disc, electromagnets, induction cup, balance beam, R, L, C, transistors, analogue ICs comparators, Microprocessors, digital ICs, digital dignal processors, Microprocessors, digital ICs, digital signal processors, Electrical qtys converted intomechanical force, torque, Level detects,comparison withreference value in analogue comparator, A/D conversion, numerical algorithm techniques. The problems have been addressed with software to automate the preparation and download of relay setting data from a laptop PC connected to a communications port of the relay. Mech. are required to construct this protective relay.. Study specialized technical articles and papers. Serious over voltage is also caused by breaking of control circuit, relay contacts etc. A Brief Introduction about Relay: RELAY: A Relay is a protection device that senses the fault in the circuit and gives a trip signal to the Circuit Breaker to isolate the faulty circuit. This calculation is repeated for all of the quantities of interest. Other software depends on the function of the relay, but can be generalized as follows: The relevant software algorithm is then applied. The choice of a protection relay rather than some other device is logical as the protection relay is probably the only device that is virtually mandatory on circuits of any significant rating. Modern numerical relays will have comprehensive self monitoring to alert the user to any problems. This is often done using a Discrete Fourier Transform (DFT) and the result is magnitude and phase information for the selected quantity. Tell us what you're thinking... we care about your opinion! In static relays, the measurement is performed by electronic/magnetic/optical or other components without mechanical motion. (many literature say both are same-Digital/Numerical Relays – T.S.M. There value may vary with respect to temperature also. Thank you , IT IS VERY HELFULL AND HELP TO IMPROOVE ELECTRICAL IND. Function Single function Single function Multi function Single function how numerical relay can be a single function ?? The alternative is to provide each input with a dedicated A/D converter and logic to ensure that all converters perform the measurement simultaneously. If maintenance is not carried out within a predefined time or number of trips after maintenance is required, the CB can be arranged to trip and lockout or inhibit certain functions such as auto-reclose. Electromechanical and static relays have fixed wiring and the setting is manual. This relay has to be installed straight only and away from magnetic field. They use one or more digital signal processors (DSP) optimised for real time signal processing, running the mathematical algorithms for the protection functions. It helps you. Relay can be broadly classified on the basis of construction and application. Jignesh Parmar has completed M.Tech (Power System Control), B.E (Electrical). The task of entering the data correctly into a numerical relay becomes a much more complex task than previously, which adds to the possibility of a mistake being made. The typical architecture of a numerical relay is shown in Figure 6. In transmission networks, it may be necessary to provide a single recorder to monitor several circuits simultaneously, and in this case, a separate disturbance recorder is still required. Function parameters are usually displayed on the front panel of the relay and through an external communications port. Supply is not required and all the Numerical Relay are Multi function relays. The numerical relays are used for various types of protection and they are classified on the basis of characteristics, Logic, Actuation parameter and application. In an over current relay or o/c relay the actuating quantity is only current.There is only one current operated element in the relay, no voltage coil etc. Its powerful six current sources (three-phase mode: up to 64 A / 860 VA per channel) with a great dynamic range, make the unit capable of testing even high-burden electromechanical relays with very high power demands. Based on Logic These classifications are made on the basis of logical operation of the relay 1. In Numerical relays measured ac quantities are sequentially sampled and converted into numeric data form. The distinction between digital and numerical relays is particular to Protection. By organising the I/O on a set of plug-in printed circuit boards (PCBs), additional I/O up to the limits of the hardware  / software can be easily added. If suitable VTs are used, supervision of the VT/CT supplies can be made available. low burden on the CT and VT, fast operation, absence of mechanical inertia and; contact trouble, long life and; less maintenance. It must work at high speed, use low voltages, yet be immune to conducted and radiated interference from the electrically noisy substation environment. The quantities can then be compared with the relay characteristic, and a decision made in terms of the following: Since the overall cycle time for the software is known, timers are generally implemented as counters. (for EM relay 100 mile ohm,other relay are 10 ohm). Best Information sir, We have China made Microprocessor based relay in hydro power projets, now we are finding alternative to same in Indian manufacturing relays. ALIND -The Power Movers. Learn about power engineering and HV/MV/LV substations. Although they are classified under different conditions their purpose remains the same, to activate the trip system when there is a fault in the electrical network. A transistor amplifier . Many functions previously implemented in separate items of hardware can then be included in a single item. this portal is very helpful to all the electrical engineering student as well as professor and technical engineer.It’s very nice and helpful for all in electrical engineering to get practical knowledge & idea very easily. Get access to premium HV/MV/LV technical articles, electrical engineering guides, research studies and much more! A. [info]It then has the capability to act as a disturbance recorder for the circuit being monitored, so that by freezing the memory at the instant of fault detection or trip, a record of the disturbance is available for later download and analysis. Numerical Relay . Under this high performing range, we are providing our clients with Static Earth Leakage Relay, Static Earth Fault Relay and Numerical Over Current Relay. The characteristics and behavior of the relay are can be programmed. B. T. S. Madhava Rao. Such voltage spikes of small duration can damage the semiconductor components and also cause mal operation of relays. The Essentials Of Numerical Relays, Their Features And Important Considerations, Electrical engineer, programmer and founder of, CB Control and State Indication / Condition Monitoring, CB Control/State Indication / Condition Monitoring, periodic maintenance of their operating mechanisms, Distance Protection – several schemes including user definable, Overcurrent Protection (directional/non-directional), Several Setting Groups for protection values, Measurement of Power System Quantities (Current, Voltage, etc. A big difference between conventional electromechanical and static relays is how the relays are wired. The widespread acceptance of numerical technology by the customer and the experiences of the user helped in developing the second generation numerical relays in 1990. C. A transistor switch . Numeric relays, on the other hand, are programmable relays where the characteristics and behavior can be programmed. Static relays are used for the protection of important lines, power stations and sub-stations. Operating Principle: They use principle of electromagnetic principle. In utility and industrial electric power transmission and distribution systems, a numerical relay is a computer-based system with software-based protection algorithms for the detection of electrical faults. Hats off. Relays detect and locate faults by measuring electrical quantities in the power system which are different during normal and intolerable conditions. Study specialized technical articles and papers. However, this technique fails when closing onto a dead but healthy line, so a level detector is also required to distinguish between current inrush due to line charging and that due to a fault. The process used for software generation is no different in principle to that for any other device using real-time software, and includes the difficulties of developing code that is error-free. The signals may be initially input to several simultaneous sample-and–hold circuits before multiplexing, or the time relationship between successive samples must be known if the phase relationship between signals is important. First generation numerical relays were mainly designed to meet the static relay protection With the aid of suitable software held by a user, it may be possible to download the new software version instead of requiring a visit from a service engineer. The values that the relay must measure to perform its protection function have already been acquired and processed. In this relays transistors and IC’s been used, They use microprocessor. This process then requires a rigorous system of software version control to keep track of: With an effective version control system, manufacturers are able to advise users in the event of reported problems if the problem is a known software related problem and what remedial action is required. Traditional electromechanical and static protection relays offers single-function and single characteristics. However you will need different types of Interfaces at the RTUs. 2nd generation relays. of starts/reaccelerations, total running time, The different software versions in existence x the differences between each version. Where multiple processors are used, one of them is a general controller of the I/O, Human Machine Interface (HMI) and any associated logic while the others are dedicated to the protection relay algorithms. First generation numerical relays were mainly designed to meet the static relay protection characteristic, whereas modern numeric protection devices are capable of providing complete protection with added functions like control and monitoring. There may be other advantages such as different logic schemes required by different utilities that no longer need separate relay versions, or some hard-wired logic to implement, and all of these reduce the cost of manufacture. The distinction between digital and numerical relays is particular to Protection. These can then be printed or uploaded to the user’s database facilities. demand in a period ( kW, kVAr; average and peak values), Motor start information (start time, total no. The argument against putting many features into one piece of hardware centres on the issues of reliability and availability. Numerical relays are the product of the advances in technology from digital relays. The distinction between digital and numerical protection relay rests on points of fine technical detail, and is rarely found in areas other than Protection: Ch 7, pp 102. i) Describe the operation of time-dependent static over current relay with a neat diagram. Tell us what you're thinking... we care about your opinion! 3 Reviews. The optimum altitude is investigated for both static and mobile UAVs. Static relays possess the advantages of having. The term ‘static’ implies that the relay has no … A solid state relay is composed of both static and electromechanical units in which the response is accomplished by the static units. If only one or two phases are lost, the VT failure algorithm can be accomplished. More than 7 decades ago, ALIND pioneered the manufacture of Aluminium conductors in India. Most of us are aware of Electromagnetic Relays and Static Relays but most us may not be well acquainted with Numerical Relay. Numeric relays are programmable relays. However, it is sufficiently accurate for an operator to assess system conditions and make appropriate decisions. This comparison summarize characteristics of all protection relay types described in previously published technical articles: References: – Handbook of Switchgear – Bhel – Digital/Numerical Relays – T.S.M. A numerical relay usually provides many more features than a relay using static or electromechanical technology. The CMC 356 is the universal solution for testing all generations and types of protection relays. Numerical relays perform many more functions than earlier generations of relays so testing them is more complex. Conventional electromechanical and static relays are hard wired relays.Their wiring is fixed, only their setting can be manually changed. For instance, an overcurrent relay at the receiving end of a transformer feeder could use the temperature inputs provided to monitor transformer winding temperature and provide alarm or trip facilities to the operator or upstream relay, eliminating the need for a separate winding temperature relay. I think it is multi-function type? The continuing reduction in the cost and size of microprocessors, memory and I/O circuitry leads to a single item of hardware for a range of functions. Any problems revealed by such tests require specialist equipment to resolve so it is simpler to replace a faulty relay and send it for repair. Since our commencement in the year 1991, we, “Prok Devices Private Limited”, an ISO 9001:2008 certified company, are well-known in the industry as an eminent manufacturer, supplier and trader, engrossed in providing Electric Relay & Meter. The first protection devices based on microprocessors were employed in 1985. The static relay is more costly as compared to the electromagnetic relay. Scope The memory can easily be expanded to allow storage of a greater time period of input data, both analogue and digital, plus the state of the relay outputs. The content is copyrighted to EEP and may not be reproduced on other websites. The standard normally used is an IRIG-B or IEEE 1588 signal, which may be derived from several sources including a GPS satellite receiver. As the power of microprocessors continues to grow and pressure on operators to reduce costs continues, this trend will continue. In this relays transistors and … For more information on the different types of disturbance recording, read this technical article. ), Consistency of operation times – reduced grading margin, Sequence quantities (positive, negative, zero), Max. Many numerical relays have the facility for time synchronisation from an external clock. Rao) 2.why In comparison table relay resistance are different unit? The most common are relay comparators based on rectifier bridges, which can be arranged as either amplitude or phase comparators. Software problems are minimized by rigorous use of software design techniques and the ability to download updated software. Numeric relays, on the other hand, are programmable relays where the characteristics and behavior can be programmed. Several extra quantities may be derived from the measured quantities, depending on the input signals available. They use principle of electromagnetic principle. Analogue signals are converted to digital form using an A/D converter. For integrated protection and monitoring systems programmable microprocessor controlled static relays are preferred. He is member of Institution of Engineers (MIE), India. ii) Write the purpose of Start of Conversion (S/C) and End of Conversion (E/C) signals in the Numerical Relay? Such relays are also termed as microprocessor type protective relays. First generation numerical relays were mainly designed to meet the static relay protection characteristic, whereas modern numeric protection devices are capable of providing complete protection with added functions like control and monitoring. Fault levels are significantly different on parts of the network that are energized under normal and emergency generation. This is perhaps the most obvious and simple function to implement, as it involves the least additional processor time. The software provided is commonly organised into a series of tasks operating in real time. Over Current/ Earth Fault:When excessive current flows through a system it will trip the circuit br… It is also easier to customize a relay for a specific application, and eliminate other devices that would otherwise be required. A numerical relay has the functionality that previously required several discrete relays, therefore the relay functions such as overcurrent or earth fault are referred to as ‘relay elements’. The book is a thoroughly revised and updated second edition of a successful text. Numerical relays are natural developments of digital relays due to advances in technology. El. An integrating circuit . Therefore solid state relays are also called as static relays. Using Protective Relay For Fighting Against Faults, The Good Old Electromechanical Protective Relay, The Solid State Relay (Static Relay) Overview, Flexibility and Reliability of Numerical Protection Relay. In industrial and small distribution networks, this may be all that is required. Note that not all functions are found in a particular relay. A relay’s ongoing performance is affected by the reliability and health of mechanical components (in the case of electromechanical relays), electronic circuits or components (static relays) and software (numerical relays). Although there is an internal clock, this is of limited accuracy and use of this clock to provide time information may cause problems if the disturbance record has to be correlated with similar records from other sources to obtain a complete picture of an event. Relay: Static Relay: Digital Relay: Numerical Relay: Technology Standard: 1st generation relays. This relay consists of two rectifier bridges and a moving coil or polarized moving iron relay. I found the article very informative thank you, The articale is very nice but i have few question. Introduction, Definition, Advantages and Disadvantages Of Static Relays Video Lecture from Introduction to Static and Numerical Relays Chapter of … Working Principle of Over Current Relay. Ok, let’s start with introduction to numerical relays, then explaining their additional features and at the end to discuss important considerations regarding software, data management, etc.. Table 1 provides a list of typical functions available, while Table 2 summarises the advantages of a modern numerical relay over static relay equivalents. Functions: 1 relay can perform various functions. Good work Jignesh, But for El Mechanical Relay like CDD21 (Alstom) Aux. Most numerical relays are also multifunctional. The continuing reduction in the cost and size of microprocessors, memory and I/O circuitry leads to a si… Power System Protection: Static Relays. One obvious development is the provision of RTU facilities in designated relays that act as local concentrators of information within the overall network automation scheme. setting can be manually changed. CT supervision is carried out more easily. Figure 1, Figure 2 and Figure 3 show typical numerical relays, while Figure 4 and Figure 5 show typical numerical relay boards. As with earlier generations of relays and according to market segmentation, manufacturers offer different versions, each with a different set of functions. However, if the DSP is overloaded it cannot complete the protection algorithm calculations in the required time and the protection function is slowed. This may obviate the need for duplicate relays to be fitted with some form of switching arrangement of the inputs and outputs depending on network configuration. It consists of one or more digital signal processors, some memory, digital and analogue input/output (I/O), and a power supply. Unfortunately, power systems change their topology due to operational reasons on a regular basis, such as supply from normal or emergency generation. numerical relay may cause many more functions to be lost compared to applications where different functions are implemented by separate hardware items. Historically, electromechanical and static relays have been provided with fixed plug settings applied to the relay. A very important things that needs to be noted is that all the three types of these Relays(Considering Digital & Numerical to be one) are SCADA Compatible. Generally, there are several different types of numerical protection relays. Finally, as well as tripping the CB as required under fault conditions, it can also be arranged for a digital output to be used for CB closure, so that separate CB close control circuits can be eliminated. Most numerical relays are also multifunctional. Practical experience indicates that numerical relays are as reliable as relays of earlier technologies. Rao. The general principle is the calculation of a level of negative sequence current that is inconsistent with the calculated value of negative sequence voltage. However, by providing a substantial number of digital I/O and making the logic capable of being programmed using suitable off-line software. The amount of data per numerical relay may be 10-100 times that of an equivalent electromechanical relay, to which must be added the possibility of user-defined logic functions. Also numerical relays have functionality that previously required separate equipment. To use these features, the appropriate data must be entered into the relay’s memory and it is good practice to keep a backup copy. 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 ”. It incorporates the latest developments in semiconductor technology and its applications to power system protection. 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Tell us what you 're thinking... we care about your opinion above diagram shows schematic. Zero ), Consistency of operation times – reduced grading margin, sequence quantities ( positive negative. The schematic of an electromechanical relay state relays are natural developments of digital and... Magnitude and phase information for the selected quantity in existence x the between. Iron relay static relay is composed of both static and mobile UAVs functionality that previously required separate equipment that all! Using an A/D converter and logic to ensure that all converters perform measurement... Eliminate other devices that would otherwise be required systems - 723 pages software so with modular hardware the signal.