List different types of protective Relaying 4. The IEEE defines protective relays as: ârelays whose function is to detect defective lines or apparatus or other power system conditions of an abnormal or dangerous nature and to initiate appropriate control circuit action â. List the applications of Static Relays 5. In a digital/numeric relay, many functions are implemented by the microprocessor programming. Relays are available from various companies such as Siemens, ABB, Schnieder Electric, Alstom, Texas instrumentations, etc. 18 FUNDAMENTAL RELAY-OPERATING PRINCIPLES AND CHARACTERISTICS Time delay is obtained in induction-type relays by a "drag magnet," which is a permanent magnet arranged so that the relay rotor cuts the flux between the poles of the magnet, as shown in Fig. ROM is also needed for storing Event and Disturbance data. In transmission line and generator protection, by the mid-1990s the digital relay had nearly replaced the solid state and electro-mechanical relay in new construction. There are two types of phase comparators: For simplicity on one-line diagrams, the protection function is usually identified by an ANSI device number. A single Numerical relay can monitor multiple parameters like current, voltage, Frequency, onset time, offset time, etc. Differential Relays 4. These relays provide different types of protection such as restrained phase differential, high set phase differential, restrained ground differential and overcurrent protection. Device number Definition and function. Motor Protection Relays 3. The response time can be changed according to the application of the relay. Inverse time relays with definite minimum time (IDMT): These Relays are mostly used in transmission lines. In a solid-state relay, the incoming voltage and current wave-forms are monitored by analog circuits, not recorded or digitized. The relay analyzes the resultant A/D converter outputs to determine if action is required under its protection algorithm(s). The analog values are compared to settings made by the user via potentiometers in the relay, and in some case, taps on transformers. Hence the Analog to digital converter is used to convert the signal to digital data. Their architecture can look confusing but we can just simplify whole architecture into these major categories. George was chairman of the IEEE Power System Relaying and Control (PSRC) committee (1981-1982) as well as a member of the "Computer Relaying Subcommittee" which was created by the PSRC in 1971 and disbanded in 1978. In short, a phase comparator compares two input quantities in phase angle (vertically) irrespective of the magnitude and operates if the phase angle between them is < 90o. We are presenting different types of relays and some important definitions with images. The numerical relays are used for various types of protection and they are classified on the basis of characteristics, Logic, Actuation parameter and application. If the protection system fails the whole network might get collapsed so they use the backup relay. This is used to display relay settings and real-time current/voltage values, etc. By contrast, an electromechanical protective relay converts the voltages and currents to magnetic and electric forces and torques that press against spring tensions in the relay. diagram of numerical relay. Trip circuit supervision relay Type TCS (English - pdf - Brochure) Bistable Relay Types PSU6n, PSU14n (English - pdf - Brochure) Circulating current relay Type IRXm (English - pdf - Brochure) Inverse-Time Overcurrent & E/F Relays Type ICM 21, ICM 21B (English - pdf - Brochure) Universal Time Relay Type NT 10 (English - pdf - Brochure) The Storage unit is a must feature because it helps in analyzing and troubleshooting any event during the occurrence of a fault. List the different types of Numerical relays 8. Components101 is a resource dedicated for electronics design engineers, covering product news, analysis and articles on latest electronics components. Numeric relays are the evolved form of a static and electromagnetic relay. Conventional electromechanical and static relays are hard wired relays.Their wiring is fixed, only their setting can be manually changed. Types of solid state relays include reed relay coupled SSR, transformer coupled SSR, and photo-coupled SSR. 1. It is also called numerical relay. SEL, AREVA, and ABB Group's were early forerunners making some of the early market advances in the arena, but the arena has become crowded today with many manufacturers. 6. 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. In 1971 M. Ramamoorty was the first to describe  calculation of impedance for distance protection using discrete Fourier analysis. A digital protective relay may also be called a "numeric protective relay". They are basically a device used for measuring electric parameters in an electrical network and convert them into numerical data which undergoes mathematical and logical analysis to decide on tripping an electrical network. 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. The first practical commercially available microprocessor based digital/numeric relay was made by Edmund O. Schweitzer, III in the early 1980s. An op-amp and comparator is used to create a DC that rises when a trip point is reached. A listing of device numbers is found at ANSI Device Numbers. 5. First of all we need to know what is Numerical Relay? 4.  George conceived of it in his Master's Thesis in 1967â68 at Newark College of Engineering. Communication languages may include Modbus, DNP3 or IEC61850 protocols. List the applications of Microprocessor based Relays 6. Any one numeric relay may implement one or all of these functions. The high powered analog signals are stepped down with current transformer and Potential transformer. Copyright 2020 © Components101. Numerical Relay Types: The following are some of the various types of numerical relays. In some solid-state relays, a simple microprocessor does some of the relay logic, but the logic is fixed and simple. (1) Electromechanical Relay: History of Relay: This is the first generation oldest relaying system and they have been in use for many years. The relay is capable of applying advanced logic. The sampling and processing of the data is done in the DSP ( Digital signal processor ) in case of numerical IEDs . Communication ports may include RS232/RS485 or Ethernet (copper or fibre-optic). Digital / Numerical Relays: Uses programmable solid state devices based on digital signal processing ... less necessary control energy compared to the output power results in higher power gain than with an electromagnetic relay. Relay symbols and device numbers; It is of two types: instantaneous over current (IOC) relay and definite time overcurrent (DTOC) relay. For instance, a differential element refers to the logic required to monitor two (or more) currents, find their difference, and trip if the difference is beyond certain parameters. A summary of some common device numbers seen in digital relays is: It has been suggested that this article be, Learn how and when to remove this template message, "Schweitzer Programmable Automation Controller", "George Dorwart Rockefeller - Engineering and Technology History Wiki", "Fault protection with a digital computer", "IEEE Herman Halperin Electric Transmission and Distribution Award", "Understanding Microprocessor-Based Technology Applied to Relaying" Working Group Report, https://www.youtube.com/watch?v=bQ6fZrrP0H4, https://en.wikipedia.org/w/index.php?title=Numerical_relay&oldid=998116552, Articles needing additional references from September 2014, All articles needing additional references, Creative Commons Attribution-ShareAlike License, 50 â Instantaneous Overcurrent (N for neutral, G for ground current), 51 â Inverse Time Overcurrent (N for neutral, G from ground current), 64 â Ground Fault (64F = Field Ground, 64G = Generator Ground), 67 â Directional Over Current (typically controls a 50/51 element), 86 â Lockout Relay / Trip Circuit Supervision, 87 â Current Differential (87L=transmission line diff; 87T=transformer diff; 87G=generator diff). 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