Hence domestic and industrial facilities are increasingly investing in microprocessor based relays to. A big difference between conventional electromechanical and static relays is how the relays are wired. The statistical data introduced by the author coincide with data of other authors and con. These include common hardware platforms, configuring the software to. There are some advantages of microprocessor are given below. This site is like a library, use search box in the widget to get ebook that you want. In electrical engineering, a protective relay is a relay device designed to trip a circuit breaker when a fault is detected 4 the first protective relays were electromagnetic devices, relying on coils operating on moving parts to provide detection of abnormal operating conditions such as overcurrent, overvoltage, reverse power flow, overfrequency, and underfrequency. Compared to static relays, digital relays introduce analogue to digital convertor ad conversion of all measured analogue quantities and use a microprocessor to implement the protection algorithm. Schwartz, schweitzer engineering laboratories, inc. The relays use programmable logic to reduce and simplify wiring. Activating the contact unit using electromagnetic attraction, which is produced when electric current exceeding the. Aging microprocessor devices approaching 20 years service. Microcontroller based overcurrent relay and directional. They are functional replacements for electromechanical protective relays and may include many protection.
The relay is operated in three zones with the required delay based on impedance. Abstractthe common format for transient data exchange comtrade file format is an ieee standard by which power. Microprocessor relays with logic and communication capabilities can accomplish this type of scheme by using either hardwired trip contacts or by using communication signals between each other to transfer statuses. In this paper the implementation of an impedance relay using 8085 microprocessor is described. Microprocessorbased distribution relay applications. The manuals are available as searchable pdf files with bookmarks and other features. For instance, a microprocessor with 3 ghz, shortly ghz is capable of performing 3 billion tasks per second. The space requirement for the microprocessor based relay scheme is much less than the electromechanical relay scheme 5, 6. The majority of mref, feeder, transformer, generator and motor protection relays. Microprocessorbased distribution relay applications schweitzer. Microprocessorbased distribution relays provide technical improvements and cost savings in.
Description the powerlogic digital relay figure 1 is a multifunction, microprocessor based device which performs these functions. Attempts, alarm contacts, security logs, setting file access, locking settings files, device firmware, traceability of. Microprocessor based overcurrent relays article pdf available in ieee transactions on industrial electronics ie331. If the capacitor switches are open and the capacitor control is in manual, close the. The functions of electromechanical protection systems are now being replaced by microprocessorbased digital protective relays, sometimes. Problems and solutions 337 examining the relay s reaction in supplying the signal to them. Microprocessorbased protective relays applications in. A datadriven approach derrick haas, matt leoni, karl zimmerman, adrian genz, and travis mooney, schweitzer engineering laboratories, inc. 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.
Thus various advantages of microprocessor based relay are. Unit i introduction of relays a relay comprises of an electromagnet and a contact unit. Your microprocessor based controller has been designed to monitor and control the conductivity of your process water. Electromechanical and static relays have fixed wiring and the setting is manual.
Life cycle experiences with microprocessor based relays. Abstract microprocessor based protective relays have. Substation commissioning to verify correct data reporting between a host device and an ied is a tedious and lengthy process. The microprocessor may use some kind of counting technique, or use the discrete fourier transform dft to implement the algorithm. Typical examples are rez 1 universal phase and ground distance relay for.
Tutorial on operating characteristics of microprocessor. By using the boolean simplification, we can represent the logic in a microprocessor based relay in a few different ways. The program can handle the online calculations and make the decision accordingly. In addition to customizing specific microprocessorbased relay capabilities, skilled integration engineers. The controller energizes two relay outputs based on a bleed and feed mode of operation. Microprocessor based relays are computers with preset programming using inputs. Understanding microprocessor based relay logic part 1. Microprocessor based overcurrent relay polytechnic hub. Microprocessor based relays are prefer able because several types of characteristics can be an overcurrent relay algorithm normally includes a implemented in the same hardware or with a minimum digital filter to extract the fundamentalfrequency com change of hardware 1,2. Modern microprocessor relays are much more powerful than their predecessors and testing.
A microprocessorbased relay applies programmable logic to establish. In general terms, auxiliary and tripping relays are supplied in 50mm cases. 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. In practice it has turned out that most mpds simply do not sense the substitution of the whole printed board of one kind for the board of other kind which is not compatible with relay current settings. Microprocessorbased protective relays deliver more.
Maintaining the digital relay data in digital format has the. Entering setpoints to the microprocessor based relay is made easier by use of a keypad and a lcd display to guide the user. Relay selection guide ge grid solutions online store. In previous publications the author has already analyzed the transition from electromechanical to a microprocessor based protective relays, and considered the prospects and problems of microproc. In some solid state relays, a simple microprocessor does some of the relay logic, but the logic is fixed and simple. The main advantage of using this relay is its capability of replacing all specific purpose relays by a single microprocessor based relay can be used for protection against various faults like over current, over voltage, thermal overload etc by just modifying the program. Different techniques and algorithms were proposed for achieving this objective.
Micro51 microprocessor based overcurrent relays are used for phase and ground overcurrent protection in utility, industrial and commercial electrical power systems. Integrity of data exchange between the field devices and a host. Microprocessor is that these are general purpose electronic processing devices which can be programmed to execute a number of tasks microprocessor is its speed, which is measured in hertz. 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 s value. The relay testing handbook 8d download ebook pdf, epub. Conventional relays like electromechanical relays employed bulky sized mechanical comparators which reduced their speed and these relays often served a single function and a single characteristic.
The microprocessor based relay furnishes easy interface with digital communication equipment. Another important advantage of the microprocessor based relay is that a microprocessor unit can perform the retransmission operation of several systems. During this process, some formatting and fonts were changed. Relay scheme design using microprocessor relays a report to the. Configuration mechanisms of modern microprocessorbased relays. Commissioning microprocessor based ied communication. Relay features the multilin feeder management relay is designed to provide complete and accurate feeder. The micro51 operates from conventional 5a or 1a secondary current transformers. The idmt relay on the hv side is also provided with an instantaneous overcurrent element. Microprocessor based over current relay current is taken from c. Numerical relays protection and control products for.
Numerical relays are based on the use of microprocessors. These microprocessor based range of relays are mounted in 50, 100, 150 and 200mm wide drawout cases. The article is a continuation of a set of the authors previous publications about the reliability of the microprocessor based protective devices. Microprocessor based relays provide technical improvements and cost savings in several ways. The se701 is a microprocessor based groundfault relay for resistance and solidlygrounded systems. Microsoft powerpoint relay scheme design using microprocessor relays. Integral to microprocessor based relay tc2 cc in1 breaker status input in2 trip circuit monitor input optional. The series 985 pdf was created by scanning pages and then recapturing the text to minimize the size of the file. The se701 can provide mainplant protection, feederlevel protection. If you have trouble reading any pages, please contact watlow and these can be sent or faxed to you. The goal of this paper is to contribute to the better understanding of microprocessor based 87l relays. Microprocessorbased relays, also called digital relays, have a proven track record of. Life cycle experiences with microprocessor based relays and roadmap to sustainability. Click download or read online button to get the relay testing handbook 8d book now.
At first it was hybrid solutions, where the time critical filtering was performed with analogue electronics. In addition to common systems, it is uniquely suited for use on systems with significant harmonic content. When the conductivity measurement goes above the user defined set point, 2 two relays are. Ieee recommended practice for microprocessor based protection equipment firmware control ieee std c37. Microprocessorbased motor relay including the following functions. In that era, the efforts were concentrated to obtain a very high speed fault clearance. Such relays are also termed as microprocessor type protective relays. Microprocessor based relays, also called digital relays, have a proven track record of reliability, with over 100,000 relay years of field experience. Typical electromechanical relay scheme panel layout. Understanding the limitations of replaying relaycreated. Tests of microprocessorbased relay protection devices. The references provide the required background knowledge and allow for further reading to explore some of the topics in greater detail.
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