1 Programmability of Numerical Relays: A Busbar Protection Relay Serves as a Traditional RTU Casper Labuschagne, Schweitzer Engineering Laboratories, Inc., Pullman, WA, USA Izak van der Merwe, Eskom Resources and Strategy Division, Cape Town, South Africa Abstract -- Numerical relays have revolutionized protection, control, metering, and communication in power systems. the selection and application of protective relays in the overall protection system, multifunctional numerical devices application for power distribution and industrial systems, and addresses some key concerns in selecting, coordinating, setting 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. For example, we have the following protections in numerical relays in-built into one relay. Sample and hold circuit 2. Figure 4 illustrates the relationship between f/# and NA. Anti-aliasing filter 3. Numerical relay is actually the digital relay as a unit for which manufacturers has developed standardized hardware, which can be used in conjunction with suitably developed software to meet variety of production requirements and applications. The Numerical Aperture (NA) and f-number (f/#) of a lens measure the amount of light it can collect based on f, D, index of refraction (n), and Acceptance Angle (θ). 36 COST OF NUMERICAL RELAYS Modern numerical protection devices have multiple protection elements and this technique makes the cost of the relay comparable with that of electromechanical and static relays … Transient testing is excellent method to validate the numerical relay algorithms based on the require application. Hardware for Metering: In principle, the hardware setup discussed above can be used for both measurement and protection function. NI 40/41 provides feeder protection applications with the best performance usability in its class and protection and numerical technology, backed by years of service performance across applications. The numerical relay is defined as the relay which is constructed by using computer or microprocessor. ABB has delivered numerical relays worldwide. Multiplexer 4. A number of applications of numerical relays are discussed. It is also called numerical relay. It is generally made of following components 1. Numerical relays are based on the use of microprocessors. APPLICATION OF NUMERICAL RELAYS FOR HV SHUNT REACTOR PROTECTION Z. Gajić, B. Hillstrőm, M. Kockott ABB Automation Technologies AB Vasteras, Sweden ABSTRACT Viewed in the substation yard, an HV, oil immersed, shunt reactor does not differ much from a power The first numerical relays were released in 1985. 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. Figures 6a - 6e compare a variety of lens systems for a relay lens, or 1:1 imaging, application. Design & Principle NI 40/41 series relays are based on numerical microprocessor based technology. Description and definition. The acceptance of numerical realsy as one-to-one substitutes for conventional relays seems to be fairly universal. A digital protective relay may also be called a "numeric protective relay". Electromechanical and static relays have fixed wiring and the setting is manual. The manufacturers have been successful in producing numerical relays that are able to operate reliably in the harsh substation environment. A big difference between conventional electromechanical and static relays is how the relays are wired. 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