This paper describes the advantages and disadvantages of a generator differential protection relay system which uses double slope characteristics of Areva P343, ABB REG670, SEL300G and GE G60. This may cause severe destructive effect on the system. The main disadvantage is it’s over heating physically. The relays used in power system protection are of different types. Software: Numerical Relays are equipped with software to communicate with external device to program to Relay or one can program by navigating through the Relay Menu. Most of the microprocessor does not support floating point operations. 47 CT Equivalent Circuit . For example, a relay including function 51 would be a timed overcurrent protective relay. It should not contact with the other external devices. The relay operation characteristic curves and restraint currents for each of algorithms are simulated by MATLAB SIMULINK. (1 relay can be used as over current only for under voltage we use another relay). Numerical relay is the relay in which the measured AC quantities are sequentially sampled and converted into numerical data that is mathematically and/or logically processed to make trip decisions. Scope. The relay has the feature of recording of parameter with the help of disturbance recorder flexibility as well as other settings. I. numerical devices of present day. (1 relay can be used as over current relay, under voltage relay etc.) What are the advantages and disadvantages of solid state relays? So during any fault nearer to the source will take much time to be isolated. The multitasking feature was mentioned earlier, and the bonus advantage is that such systems do not occupy large spaces to operate. Keywords-Electromechanical relay, numerical relay, Local breaker backup, Bus bar protection, Goose feature in Numerical relay. Hardware for Metering: In principle, the hardware setup discussed above can be used for both measurement and protection function. Most numerical relays are also multifunctional. Numerical relays are the result of the application of microprocessor technology in relay industry. Among them differential relay is very commonly used relay for protecting transformers and generators from localised faults. Using an OTP can not only save you a lot of expenses and headaches but also provide your clients with peace of mind, knowing that their credentials are safe. The various protective functions available on a given relay are denoted by standard ANSI device numbers. The performance of the introduced relay model was tested at … Numerical relays are micro processor based relays and having the features of recording of parameter used as disturbance recorder flexibility of setting & alarms & can be used one relay for all type of protections of one equipment hence less area is required. Numerical Single-Phase and Three-Phase Reclosing System Digital Transformer Protection Transformer Tap Changer Controller Terminal Boards Multiple Feeder Management Relay Bay Controller: Generator Management and Control System Phase Packaged Directional-distance Relay Substation Automation Power Directional Relays Ground Distance Relay Automatic Synchronizing Relay Auxiliary or … Finally, Numerical relays represent best compromise between: economy and performance dependability and security complexity and simplicity speed and accuracy credible and conceivable. Differential relay :- A two-winding relay that operates when the difference between the currents / Voltage in the two windings reaches a predetermined value is called differential relays. INTRODUCTION Protection is the important aspect to be considered in power … Stability setting is then in essence the determination of RS. To solve the title problem, the parameter transfer method is introduced first. The relay application for protection of power system date back nearly 100 years ago. Advantages ① It has been widely used in numerical control and automatic control. Z R in the operating signal is a voltage drop from the relay current (I) across the impedance between the relay and R). Since … Functions: 1 relay can perform various functions. * Answer. DISADVANTAGES OF ELECTROMECHANICAL RELAYS 1) Electromechanical Relay uses mechanical parts that makes it bulky and larger in size. Since the password (a four or six-digit numerical PIN code in most instances) can be entered just once, it’s not as risky as static passwords that can be used a second time. 45 I relay = I primary* N 1/N 2 I relay = I primary* N 2/N 1 -I exciting CT Accuracy. Advantages and disadvantages of selected algorithms are investigated based on speed, sensitivity and security. Over Current Line Protection by Inverse Relay. 1 relay can perform only 1 function. Numerical Relay 4.1 Introduction Nowadays the modern power system have grown both in size and complexity so it require fast ,accurate and reliable protective schemes to protect major equipment and to maintain system stability. These disadvantages of using microprocessors. As compared with single transistor, driving the inductive loads with Darlington pair is more effective since it offers a high load current with a small base input current. Static Relays Disadvantages 1.Reliability cannot be predicted 2.Construction is not very robust. Here, a case study relating to both electromechanical relay and numerical relay will be done and the results are analyzed. More complex digital relays will have metering and communication protocol ports, allowing the relay to become an element in a SCADA system. Below figure shows a Darlington pair that drives the relay coil. Developer on Alibaba Coud: Build your first app with APIs, SDKs, and tutorials on the Alibaba Cloud. Overcurrent relay. Applications 1.Ultra high speed protection of EHV AC transmission lines utilizing distance protection. Digital/numerical relays provide a front panel display, or display on a terminal through a communication interface. The numerical relay system based protection devices cater to generation, transmission and distribution systems. This is used to display relay settings and real-time current/voltage values, etc. There are some disadvantages of microprocessor are given below, The microprocessor has a limitation on the size of data. A Buon Tua Srah Hydropower Plant in Vietnam was selected as an example for the relay setting calculations of these characteristics. Numerical Relaying Fundamentals : An Introduction Why Numerical Relaying? Last Update:2017-01-19 Source: Internet Author: User. 4. Disadvantage of Definite Time Line Protection. When the frequency of use is low, with the delay in response time caused by a condenser, it is possible to absorb the chattering and bouncing. Numerical relays are all microprocessor based, but there are relays that take the advantage of microprocessor technology and are not fully numerical. Read more > A method of parameter transfer. 3.Easily affected by surrounding interference. 44 Wound type CT - MV Primary Winding. Electromechanical and Static relays are not multifunctional unlike Numerical relay. Numerical relays have the ability to communicate with its peers, are economical and are easy to operate, adjust and repair. It is also possible to use the Darlington pair to drive the inductive loads such as relays, motors. can be overcome by using DSP. Numerical Relays are being increasing used in transmission and distribution and industrial electricity networks. As the protected components of the electrical systems have changed in size, configuration and their critical roles in the power system supply, some protection aspects need to be revisited (i.e. Relays by functions. Modern protection relays; Multifunctional protection; Product benefits. Advantages And Disadvantages Of Static Relay 1044 Words | 5 Pages. Most numerical relays are also multifunctional and have multiple setting groups each often with tens or hundreds of settings. Numerical relays are microprocessor and microcontroller based relays having its own memory Numeric relays take the input analog quantities and convert them to numeric values. overcome the disadvantages of electromechanical relays. RSinternal to relay. 46 CT Equivalent Circuit . Wide Range of setting, more accurate, Low burden hence low VA of CT is required which minimize the cost. the use of protection systems to reduce arc flash energy in distribution systems). Modeling of digital and numerical relays is important to adjust and settle protection equipment in electrical facilities and to train protection personnel. A numerical implementation method for Java Exchange two variables _java. If the number of sections in the line is quite large, the time setting of relay nearest to the source would be very long. relay which is very essential in order to meet the . Numeric relays, on the other hand, are programmable relays where the characteristics and behavior can be programmed. 4.Auxiliarty DC supply is required 5,.Affected by voltage transients. Delay in operation: Easily provided Relays detect power flowing in the wrong direction – results in power outages Polarity. The DSP is able to improve the performance of the . Differential relays are very sensitive to the faults occurred within the zone of protection but they are least sensitive to the faults that occur outside the protected zone. This course discusses the differences between static, digital and numerical relays and the advantages of numerical relays are presented and contrasted with electromechanical and static relays. 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