1 decade ago. The advantage of this relay is that it is less likely to operate inaccurately than a differentially connected over current relay when a short circuit occurs external to the protected zone. It provides medium and low voltage networks with an optimized composition of protection functions within one relay. The following are the benefits of static relays. on a numerical relay which is composed of rms current converter, integrator, comparator, low-pass filter and reset logic. Numerical Relays working explained in this post with the help of a Numerical relay used in industrial applications. Electromechanical, have been gradually been replaced by Static and then by Numerical Relays. Multiple relay characteristics The range of operation of traditional models is narrow while numerical relays are diverse and evolution adaptable. iv ACKNOWLEDGEMENTS The author expresses his gratitude and appreciation for Dr. M. S. Sachdev and Dr. T. S. Sidhu for their supervision of this work. A Numerical Protection Relay Solution 4 Simultaneous Sampling Requirements In most NPRs, the phase relationship between the signals captured from different channels is as important as the value of the signal. Numerical Relay Advantages & Impact on Scheme Design Integration of a suite of Protection & Control functions. It uses a flag system for the indication purpose whether the relay has been activated or not. Numerical relays are all microprocessor based, but there are relays that take the advantage of microprocessor technology and are not fully numerical. This implies that Reactance Relay is an over-current Relay with directional Restraint. Answer Save. They are reliable. Voltage Balance Differential Relay Under normal healthy condition, the two voltages e1 and e2 are same ,so the difference between them is zero. Advantages of numerical relays. ADVANTAGES OF NUMERICAL RELAYS 1) Compact Size: Numerical relay is compact in size, and uses LCD to indicate relay activation. No special programming device is required. Numerical relays are all microprocessor based, but there are relays that take the advantage of microprocessor technology and are not fully numerical. December 2018; Conference: CIGRE Paris Session 2018 ; Authors: Sanjay Patki. The directional element is so designed to give Maximum Torque Angle (MTA/RCA) of 90 degree. As a result of advances in technology, they can be viewed as natural developments of digital relays. This necessitated providing adequate automatic protection for transformer against possible faults. Advantages of Numerical relays: Compact Size: Electromechanical Relay makes use of mechanical comparison devices, which cause the main reason for the bulky size of relays. NUMERICAL RELAY CHARACTERISTICS 2.1 General Characteristics Num erical relays are highly co mpact devices, characterised with fast operation, high sensitivity, self monitoring, and low maintenance. It is also called numerical relay. In some cases where the kW rating of LT motor is more (generally more than 75 kW), CTMM or Numerical Relays are used. Voltage Balance Differential Relay 36. Relevance. Electromechanical and static relays have fixed wiring and the setting is manual. Kulkarni Suyash. A numerical relay has got several advantages as compared to ordinary electromagnetic relays. With their unique advantages they eliminate use of a thermal/bimetal relay for motor protection. While Numerical Relay … Siemens SIPROTEC series have been used as an example of numerical relays, specifically 7SJ64 as OC relay, which exists in the ETAP library. 15.1 Fundamental Principle of Overcurrent Relay 15.1.1Limitations of a Fuse Advantage of fuse based protection is its simplicity and cheapness. Advantages of Numerical relays: Compact Size Flexibility Multi Function Capability Different types of relay characteristics Digital communication capabilities Modular frame Sensitivity Speed Fast Resetting Data History (1)Nature of fault, (2) Magnitude of fault level, (3) Breaker problem, (4) C.T. 2) Flexibility: We can modify its functional operation by changing codes in software. The values can be easily set. The distinction between digital and numerical relay rests on points of fine technical detail. I But by combining many features into one piece of hardware, numerical relay centres on the issues of reliability and availability. The definition is: Activating the contact unit using electromagnetic attraction, which is produced when electric current exceeding the specified value flows to the electromagnet; the voltage and current (input signal) applied to the coil opens or shuts the contact. Therefore from Universal Torque Equation, T = K 1 I 2 +K 2 V 2 +K 3 VICos(Ɵ-Ƭ)+K 4. A digital protective relay may also be called a "numeric protective relay". Spring Disc Time Adjustment: Tension controlled Contacts Core Sensing Coil Electro Mechanical (Start of Century) 2. The reset time of the relay is very less. The first numerical relays were released in 1985. The Advantages of Electromechanical relays are-They are quick acting and can be reset fast. -controller Current SamplingB CA E Direct AC Sampling Output Control … monophoto. Ltd., Kolkata, West Bengal. Advantages of Static Relay. However, in LT motors, above five protections are used differently. -controller Current SamplingB CA E AC - DC Conversion Output Control Steady state data Relay Contacts Crystal Micro Controller Based (Late 80s) 3. Self-check feature improves the protection system reliability. Numerical three phase over current and earth fault Relay Type NI 40/41 Application The NI 40 / 41 Feeder Protection Relay is ABB's new and advanced solution for cost-efficient feeder protection relay. Electromechanical Relay makes use of mechanical comparison devices, which cause the main reason for the bulky size of relays. A DSP from Texas Instruments, TMS320F2812 is chosen to build the overcurrent relay according to inverse definite minimum time (IDMT) characteristics. advantages over the other relays such as reduced size, reduced number of protection elements, reduced cost, increased speed etc. Numerical method is the best method to design relay due to following advantages: ISSN: 2319-8753 International Journal of Innovative Research in Science, Engineering and Technology And the simulation results show the advantages of the proposed method in reducing the time needed by the relay to clear the electrical fault. Download full … 35. Putting K2 = 0, K4 = 0 and Ƭ = 90° we get the Torque in Reactance Relay as. Exporter of Numerical Relays - Numerical Relays - MiCOM C264-P, Numerical Relays - MiCOMho P446, P443 and P445, Numerical Relays - Bitronics 70 Series Measurement System and Numerical Relays - P991 Test Block offered by Fidere Engineers & Services Pvt. 2 Answers. NUMERICAL RELAY TESTING AND VALIDATION IN RELAY LIFE CYCLE. 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. However, Electromechanical Relays are still being used. It requires less wiring so it is not having complex architecture. TMS320F2812 is a high performance processor which is … what are the advantages of numerical protective relay when compared with other types? 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