This paper describes a multimicroprocessor based distance re. For the most effective protection, many utilities and industrial facilities are replacing aging electromechanical relays with new generation microprocessor based relays. In utility and industrial electric power transmission and distribution systems, a digital protective relay is a computer based system with software based protection algorithms for the detection of electrical faults. The article is a continuation of a set of the authors previous publications about the reliability of the microprocessorbased protective devices. Abstractwith increasing use of microprocessor based re lays, incorporating logic into relays.
From the above description, we can draw the following block diagram to represent a microprocessor based system. Figure 2a shows a typical ac schematic, and figure. Jun 30, 2017 numerical relay is the relay in which the measured ac quantities are sequentially sampled and converted into numerical data that is mathematically andor logically processed to make trip decisions. In the event of a fault, protective relays protect electrical systems, equipment, and people from serious damage and injury. Advantages due to the use of indication on lcd for relay activation the numerical relay is in compact size. Application guidelines for microprocessorbased, high. The channel selection is done by the microprocessor and the information is carried on to the adc through the chip 74ls144. Vmc8506 provides facility of dip relays on its board. For simplicity on oneline diagrams, the protection function is usually. Tests of microprocessorbased relay protection devices. The best example of an embedded system is a microprocessor. The article is a continuation of a set of the authors previous publications about the reliability of the microprocessor based protective devices. The output of the ct line is given to the input receiver block where the signal is processed.
Using a microprocessorbased relay, we can program these functions internally. The whole circuit of 8085 based home security system consist transmitter, receiver, phaselockedloop and processing section as shown in block diagram. Fundamentals of microprocessor based protective relays suhag patel, p. Index terms boolean logic, continuous function chart, execution order, task cycle. Today, the industry is testing 9 star cameras sunshades scissors. Figure shows the block diagram of the microprocessorbased relay. That kit used for this purpose is vinytics vmc 8506 which has an inbuilt adc interface based on adc0809 chip and also some relays which can be turned on or off by providing simple 8085 instructions. This paper proposes a protection strategy based on microprocessorbased relays for low.
A software controlled analogtodigital converter input for a microprocessor system can be created with softwear, a processor and a digitaltoanalog. Dec 28, 2015 fundamentals of microprocessor based relays 1. Numerical relays allow for a variety of protection systems to be applied with minimal additional cost. The central processing unit is the heart of the plc system. Now, microprocessor based digital relays are becoming the norm for new installations and many replacements, because of their improved protective capabilities, reliability, and additional features. Microprocessorbased timeovercurrent relay micro51 micro51 microprocessor based overcurrent relays are used for phase and ground overcurrent protection in utility, industrial and commercial. Experimental results with better relay characteristic performances and high flexibility for implementing the desired value of n, including noninteger values, are obtained. Microprocessorbased protective relays applications in nigeria.
Understanding microprocessor relay logic basic digital. Microprocessor based relays allow us to change configuration of the relay protection set. Microprocessor based relays, also called digital relays, have a proven track record of reliability, with over 100,000 relayyears of field experience. A big difference between conventional electromechanical and static relays is how the relays are wired. Design and implementation of oc relay using microprocessor. Understanding microprocessor based relay logic part 1. The address 8087 here means that any of the addresses from 80 to 87 can be used. The result of using electromechanical relays has been an extensive maintenance and design practice. Inverse overcurrent is normally associated with the overcurrent relay types, the operation time is inversely proportional in certain degrees with their. The hardware and software design of the proposed microprocessor based system are described as below. The designs and the operation of these plants are determined by the criteria of economy availability and safety. These dip relays have an address 8087 and are used in io mapped mode.
The other forms of inputs such as heat, light, magnetic field, traveling waves, etc. What is block diagram of microprocessor based relay for. The electromechanical scheme requires nearly all of the space contained in a 2cm. Ppt microprocessor based power system protection powerpoint. Chapter 2 introduction to microprocessor based control. Journal of microcomputer applications 1983 6, 1523 microprocessor based distance relays badri ram and b. Abbs numerical relay type spad 330 c designed to be used as a fast interwinding shortcircuit and interturn fault protection for twowinding power transformers and power plant generatortransformer units. Download scientific diagram block diagram of microprocessor based relay from publication.
Plc programmable logic control block diagram, input. A processor appears only once in a plc and it can be either a onebit or a word processor. Long before the advent of microprocessor relays, protection and control was. Changes can be made within microprocessor based relaying systems with. Numerical relay is the relay in which the measured ac quantities are sequentially sampled and converted into numerical data that is mathematically andor logically processed to make trip decisions. Liew department of electrical engineering, ivational unmersrty of singapore, 10 kent ridge cresccn, singapore 119260. Relay scheme design using microprocessor relays a supplement to relay trip circuit design by ieee psrc 1999 4 1 introduction microprocessor based relays have been replacing electromechanical and solid state technology relays. Chart and diagram slides for powerpoint beautifully designed chart and diagram s. Inside the microprocessor internally, the microprocessor.
Critical to performance of any relay logic scheme are the comprehensive testing. Chapter 2 introduction to microprocessor based control objectives after studying this chaptet you should be able to unalerstand what a microprocessor is. A block diagram of microprocessor based digital control system along is shown in figure2 1. Microprocessor based overcurrent relay polytechnic hub. Microprocessor based tion relas, crcuit diagrams a. Function block based logic design can help create logic templates that can be used. Numerical relays protection and control products for power. Function block based logic design can help create logic templates that can be. The block diagram of a typical microprocessorbased relay is shown in figure. This paper evaluates the performance of a transmission line protection scheme using microprocessor based protective and electromechanical relays using discrete components. The program can handle the online calculations and make the decision. In this paper the implementation of an impedance relay using 8085 microprocessor is described.
They are functional replacements for electromechanical protective relays. Operation and maintenance of protective relays and associated. Numerical relays are based on the use of microprocessors. Time delay based relay operated load block diagram by. Microprocessorbased transmission line relay applications abstract. Microprocessor based relays, also called digital relays, have a proven track record of reliability, with over 100,000 relay years of field experience. Signal processing includes overvoltage protector, rectifier, smoothing filters, auxiliary ct, etc. Microprocessorbased overcurrent relays ieee journals. The statistical data introduced by the author coincide with data of other authors and con. Microprocessor based relays 1 microprocessor based relays implementation, conflicts, and corrective actions steven v. Draw the block diagram of a microprocessor based computer system showing the address, data and control bus structure.
We have shown the block diagram, circuit diagram used by us to control a small. In utility and industrial electric power transmission and distribution systems, a digital protective relay is a computerbased system with software based protection algorithms for the detection of electrical faults. A proposed scheme of overcurrent relays dealing with programming of the singleboard microcomputer tk85, built by nec around intels 8bit 8085 microprocessor, is described. Microprocessor based transmission line relay applications abstract for many years, utilities have used electromechanical relays for power system protection. The application of protection relaying in power systems, using mbpr systems. Microprocessor based digital control system figure 2 shows the analog input and output through ad and da converter. In the microprocessor based computer system, three buses exist for transfer of address, data and control information between the microprocessor and its memory and. Microprocessorbased protective relays applications in. Figure 1 is the basic block diagram of a mbpr showing. Short circuit and other abnormal conditions often occur on a power system. The microprocessor contains millions of tiny components like transistors, registers, and diodes that work together. Numerical relays are all microprocessor based, but there are relays that take the advantage of microprocessor technology and are not fully numerical. Microprocessorbased distribution relay applications. For example, an overcurrent relay may be required to use data of three phase currents and the residual current.
Nov 08, 20 this is a recreation of the first paper i ever presented from the neta conference in 2001 that was the foundation of the relay testing handbook series. Analysis of microprocessor based protective re lays mbpr. Understanding microprocessor relay logic basic digital logic. Such relays are also termed as microprocessor type protective relays. Time delay based relay operated load working and its block.
A microprocessor based relay scheme is very simple to test and verify. The cpu is a microprocessor based control system that replaces central relays, counters, timers and sequencers. Typical block diagram of numerical protection relay typical block diagram hardware and software architecture. Microprocessorbased negative sequence relay s i ahson and j henry department of electrical engineering, indian institute of technology, new delhi 110016, india d s rundhay corps of engineers. Coordinate with branch fuses after initial reclose block instantaneous overcurrent functions to allow fuse to blow after successful.
Static relays can be arranged to respond to electrical inputs. A digital relay is required to receive one or more power systems operational parameters. Therefore, you can connect the cts in wye on both sides of the bank, regardless of the transformer bank connection. 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. The figure below gives a block diagram of a microprocessor based digital, programmable static relay. Control of dc drives using microprocessors applications.
As a result, the software used for programming would need to automatically. The operation of the various functions and logic has been fully. Microprocessorbased transformer differential relays can make the delta internally. Microprocessor based distribution relays contribute to improved reliability and reduced costs on electric power systems. Basic concepts of microprocessors differences between. Nov 11, 20 understanding microprocessor based relay logic part 2 digital logic.
This is really much more convenient than to install. Microcontroller based overcurrent relay and directional. Block diagram of microprocessor based relay download scientific. A computer, large or small, can be represented functionally in a simplified form by the block diagram in figure. Power system, microprocessorbased relays, electromechanical relays. This video discusses how you can convert the digital relay logic found in microprocessor based relays and translate that.
Electric power systems research 38 1996 11 i7 microcontroller based overcurrent relay and directional overcurrent relay with ground fault protection zhijun gan, s. The cpu is a microprocessor based control system that replaces central relays, counters, timers and. The thyristor based system is good but when used with microprocessor based speed controller they are really good. Flexibility and reliability of numerical protection relay on photo. A microprocessor consists of an alu, control unit and. An electrical power system consists of generators, transformers, transmission and distribution lines. Ppt microprocessorbased relays powerpoint presentation.
Electromechanical and static relays have fixed wiring and the setting is manual. Chakravarty bihar college of engineering, patna 800 005, bihar, india this paper presents a microprocessor based distancerelaying scheme suitable for the protection of ehv lines. Microprocessor based home security system electronics. Have galvonic isolation by optocouoler or some other device. Understanding microprocessor based relay logic part 2. Architecture of the modern numerical or microprocessor based relay. Part 1 gives a brief history of protective relays to see how technology has changed over the years and presents some pros. Study and analysis of modern numerical relay compared to. Figure shows the block diagram of the microprocessor based relay. Microprocessorbased relays allow us to change configuration of the relay protection set. The fault current and voltage are fed to the adc through channel 1 and channel 0. Microcontroller based protective relay testing system. Relay scheme design using microprocessor relays a supplement to relay trip circuit design by ieee psrc 1999 4 1 introduction microprocessor based relays have been replacing electromechanical and solid state technology relays for several years. As shown, it comprises of three basic parts or subsystems.
This is a recreation of the first paper i ever presented from the neta conference in 2001 that was the foundation of the relay testing handbook series. Problems and solutions 335 periodicity once in 4 years only for electromechanical relays is established. The basic block diagram of the scheme is shown in fig. Analysis of microprocessor based protective re lays. Numerical and microprocessor relay comparison answers. Microprocessorbased transmission line relay applications. Flexibility and reliability of numerical protection relay. Application guidelines for microprocessorbased, highimpedance bus differential relays stanley e. Microprocessorbased digital static relay static relays can be arranged to respond to electrical inputs. In the microprocessor based computer system, three buses exist for transfer of address, data and control information between the microprocessor and its memory and io system. Numerical relays are microprocessor based relays whereas the other relays are controlled electromechanically. Block diagram of microprocessor based system answers.
Zocholl and david costello, schweitzer engineering laboratories, inc. Also, microprocessorbased relays can provide easy current magnitude and angle checks to ensure proper connections. In addition to customizing specific microprocessor based relay capabilities, skilled integration engineers can also help utilities and industrial facilities design their microprocessor based relay protection systems in such a way as to fully leverage the inherent benefits of the relays and maximize each relay. Abstracthighimpedance bus differential relays have been applied successfully for decades. Microcontroller based mho relay for distance protection. Significant features of microprocessor based relays that serve to enhance protection previously available through application of traditional relaying include the following. Microprocessorbased negativesequence relay sciencedirect. Microprocessor based dcs modern plants nowadays are very complex, large scale systems with a very high degree of automation.
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