The curve selection on a microprocessor based relay. The pmd series incorporate a microprocessor based design capable of advanced signal processing including true rms voltage measurement. Description the powerlogic digital relay figure 1 is a multifunction, microprocessor based device which performs these functions. Rebirth of negativesequence quantities in protective. Example relays microprocessor based relays 64g elements basic testing fundamentals zone 1 pickup looks for a 60 hz overvoltage condition applied to the relay neutral voltage inputs. The micro51 operates from conventional 5a or 1a secondary current transformers. Plunger type electromagnetic relays formed instantaneous units for detecting overcurrent or overvoltage conditions. Relay logic is very important to understand the microprocessorbased relay. By using the boolean simplification, we can represent the logic in a microprocessor based relay in a few different ways. Figure shows the block diagram of the microprocessor based relay. Timeovervoltage relay and protection assemblies rxeda 1 and raeda features rxeda relay. Microprocessor based timeovervoltage relay for dc and. Once the field is used and the 59p operates, the 273n protection is enabled. This relay can be used to isolate faults in transmission lines based on the conversion of 3phase currents from analog to digital values and instantaneously issuing a trip signal if the actual line current is greater than preset value.
The digital protective relay is a protective relay that uses a microprocessor to analyze power system voltages, currents or other process quantities for the purpose of detection of faults in an electric power system or industrial process system. Chakravarty bihar college of engineering, patna 800 005, bihar, india this paper presents a microprocessor based distancerelaying scheme suitable for the protection of. Application guidelines for microprocessorbased, high. Overload protection using microprocessor based overvoltage relay. Microprocessorbased protective relays applications in. Generalizing modern microprocessor based relay protection at the power transmission line, a design of relays based. This relay can be used to isolate faults in transmission lines based on the conversion of 3phase currents from analog to digital values and instantaneously issuing a trip signal. Microcontrollerbased under and over voltage protection device. Eberle regd microprocessor voltage control relay regdda v1.
Experimental results with better relay characteristic performances and high flexibility for implementing the desired value of n, including noninteger values, are obtained. Early versions used discrete devices such as transistors and diodes in conjunction with. The mu2300 voltage protection relay is a microprocessor based numerical relay intended for the voltage protection in electrical distribution network. To explain the constructionworking of a simple microprocessor based overcurrent relay. 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. This is really much more convenient than to install. Microprocessorbased protective relays applications in nigeria. Numerical relays protection and control products for.
Electric power systems research 38 1996 11 i7 microcontroller based overcurrent relay and directional overcurrent relay with ground fault protection zhijun gan, s. Type micro51 and micro51ft microprocessorbased timeovercurrent relays english pdf catalogue. Microprocessor based relays allow us to change configuration of the relay protection set. Microprocessorbased distribution relay applications. This comparison summarize characteristics of all protection relay types described in previously published technical articles.
Start with voltage less than zone 1 setting and ramp up. This paper evaluates the performance of a transmission line protection scheme using microprocessor based protective and electromechanical relays using discrete components. Timeovervoltage relay and protection assemblies rxeda 1 and. The moment the input voltage falls below the predetermined reference, the transistor conducts and triggers a relay which cuts off the power. Power system protection part power system protection. Siprotec microprocessor based protective relay history of protective relay. Pmrutl series the pmrutl series phase monitor relays utilize a microprocessor based design to provide protection against phase loss, phase reversal, phase unbalance, undervoltage and overvoltage. Despite their advantages, the new technology was competing with wellproven devices. A proposed scheme of overcurrent relays dealing with programming of the singleboard microcomputer tk85, built by nec around intels 8bit 8085 microprocessor, is described. 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, over voltage, reverse power flow, overfrequency, and underfrequency. Utilities, however, are starting to replace electromechanical relays with new microprocessor based relays. A nondirectional overcurrent relay shall be used to supervise the distance relays. Typically several standard curves are provided for user selection. Zocholl and david costello, schweitzer engineering laboratories, inc.
The statistical data introduced by the author coincide with data of other authors and con. Microprocessor based overload relay 3rb20 and 3rb21. Now, microprocessor based digital relays are becoming the norm for new installations and many replacements, because of their improved protective capabilities, reliability, and. Basic principle of digital relays or methodology used. In some solid state relays, a simple microprocessor does some of the relay logic, but the logic is fixed and simple. Microprocessorbased relays allow us to change configuration of the relay protection set. A big difference between conventional electromechanical and static relays is how the relays are wired.
Pdf inverse overcurrent is normally associated with the overcurrent relay types, and the operation time is inversely proportional in certain degrees. Micro51 microprocessorbased overcurrent relays are used for phase and ground overcurrent protection in utility, industrial and commercial electrical power systems. Integrated surge arrester against transient overvoltage. The microprocessor may use some kind of counting technique, or use the discrete fourier transform dft to implement the algorithm. A combination of electromechanical and microprocessor. Chapter 2 introduction to microprocessor based control. Tutorial on operating characteristics of microprocessor. 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 for several years. Generalizing modern microprocessor based relay protection at the power transmission line, a design of relays based on arm.
The article is a continuation of a set of the authors previous publications about the reliability of the microprocessor based protective devices. Eberle reg5a static voltage control relay reg 5e 5a reg 5e 5a 39 a. Micro51 microprocessor based overcurrent relays are used for phase and ground overcurrent protection in utility, industrial and commercial electrical power systems. Activating the contact unit using electromagnetic attraction, which is produced when electric current exceeding the. The output of the ct line is given to the input receiver block where the signal is processed. The emphasis is on numerical relays since they have facilitated the. Stage 1 is programmable for the following two different time functions. Similarly, the output of a logic function is activated, that is, high or deactivated, that is, low. Numerous protection functions such as time overcurrent, under and over voltage, and voltsperhertz may use inverse time characteristics. Numerical relays are based on the use of microprocessors.
Phase monitor relays protect against single phasing regardless of any regenerative voltages. Chapter 2 introduction to microprocessorbased control objectives after studying this chaptet you should be able to unalerstand what a microprocessor is. Altuve, and normann fischer schweitzer engineering laboratories, inc. 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. Journal of microcomputer applications 1983 6, 1523 microprocessorbased distance relays badri ram and b. Early works on the topic involves building of discrete circuits each for under voltage and overvoltage. One which has no intentional timedelay and operates in. Get access to premium hvmvlv technical articles, electrical engineering guides, research. Timeovervoltage relay and protection assemblies rxeda 1. Time overundervoltage relay rxedk 2h and and protection. Microprocessor based distribution relays contribute to improved reliability and reduced costs on electric power systems. Rebirth of negativesequence quantities in protective relaying with microprocessor based relays fernando calero schweitzer engineering laboratories, inc. It can also be used for generators, motors and transformer protection.
Operation and maintenance of protective relays and. The relay is selfpoered from the current, therefore, there is no continuous drain on. Microprocessor based relays, also called digital relays, have a proven track record of reliability, with over 100,000 relay years of field experience. Microcontroller based overcurrent relay and directional. A collection of technical papers representing modern solutions, 2014.
Unit i introduction of relays a relay comprises of an electromagnet and a contact unit. A fully digital user interface with bright sevensegment display and. The induction disc relay produces a circular motion that is propostional to the coil current. The mh rea200 is designed as a universal, digital microprocessor based protective relay, integrating both the overcurrent and earth fault protection schemes for definite and inverse time characteristics within one compact unit. It also covers power system, transformer protection and zone of. These products detect single phasing and unbalanced voltages regardless of regenerative voltages. Numerical relay, over current protection, overunder. Signal processing includes overvoltage protector, rectifier, smoothing filters, auxiliary ct, etc. Both designs have performed reliably since their introduction over 100 years ago. 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. Eberle pantavolt e static voltage relay generic overvoltage generic overvoltage 36 a.
Microprocessor based overcurrent relay polytechnic hub. Microprocessor based over current relay current is taken from c. Abstracthighimpedance bus differential relays have been applied successfully for decades. The pmp series incorporate a microprocessor based design capable of advanced. Microprocessor based jockey pump controller effective june 2015 eaton industries canada company. The mu2300 voltage protection relay is a microprocessor based numerical relay. Time overundervoltage relay and protection assemblies rxedk 2h and raedk 1mrk 509 004ben page 2 application rxedk 2h is a time overundervoltage relay with two measuring stages, which are switchable for over or undervoltage functions independently of each other. A digital protective relay may also be called a numeric protective relay.
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