Note for Switch Gear & Protective Devices - SGPD by Vssut Rulers

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SWITCHGEAR AND PROTECTIVE DEVICES 2015 Lecture Notes on SWITCH GEAR AND PROTECTIVE DEVICES 7TH SEMESTER BTECH (EE) SUBJECT CODE: BEE 1701 VEER SURENDRA SAI UNIVERSITY OF TECHNOLOGY Department of Electrical Engineering Burla, Sambalpur, Odisha 768018 www.vssut.ac.in 1|Page

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SWITCHGEAR AND PROTECTIVE DEVICES 2015 DISCLAIMER This document does not claim any originality and cannot be used as a substitute for prescribed textbooks. The information presented here is merely a collection by the committee members for their respective teaching assignments. Various sources as mentioned at the end of the document as well as freely available material from internet were consulted for preparing this document. The ownership of the information lies with the respective authors or institutions. Further, this document is not intended to be used for commercial purpose and the committee members are not accountable for any issues, legal or otherwise, arising out of the use of this document. The committee members make no representations or warranties with respect to the accuracy or completeness of the contents of this document and specifically disclaim any implied warranties of merchantability or fitness for a particular purpose. The committee members shall not be liable for any loss of profit or any other commercial damages, including but not limited to special, incidental, consequential, or other damages. 2|Page

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SWITCHGEAR AND PROTECTIVE DEVICES 2015 SYLLABUS SWITCHGEAR AND PROTECTIVE DEVICES (3-1-0) MODULE-I (10 HOURS) Protective Devices: Philosophy of protection, Nature, Causes and consequences of faults, Zone of protection, Requirements of a protective scheme, Basic terminology components of protection scheme. Relay classification, Principle of different types of electromagnetic relay. General equation of phase and magnitude comparators, Duality of comparators, Electromagnetic relays, over current relays Directional relays, Distance relay- impedance, Reactance and Mho type, Differential relays. MODULE-II (10 HOURS) Feeder: Protection: Over current and earth fault protection, Distance protection, Pilot wire protection, Carrier current protection. Generator Protection: Biased differential protection, restricted earth fault protection, Field suppression, Negative sequence protection, Earth fault detection in rotor circuit Power transformer Protection: Biased differential protections, restricted earth fault protection, Buchholz relay Protection of combined transformer and alternator. Bus Zone Protection: frame leakage and circulating current scheme-use of Translay relay. MODULE-III (10 HOURS) Circuit Breakers: Formation of arc during circuit breaking. Characteristics of electric arc. Theories of arc Interruption. Recovery and restriking voltage, interruption of capacitive and inductive currents. Current chopping. Principle of A.C. and D.C. circuit breaking requirements of good circuit breaker circuit breaker rating. Different types of circuit breakers. Air break and Air blast circuit breaker. Plain break and controlled break all circuit breakers. Minimum oil circuit breakers. Vacuum circuit breaker, SF6 circuit breaker. D.C. Circuit breaker. H.R.C. Fuse: Construction and characteristics MODULE-IV (10 HOURS) Static Relays : Development and classification of static relays, Different types of phase and amplitude capacitors, Basic static relays used in protective scheme, Elementary idea about digital & numerical protection. Testing and maintenance of protective gear, Protection against surge-surge absorber, Surgediverter. Arrangement of Bus bar, Circuit breaker and isolator. Current limiting reactors in power system and their arrangement calculation of fault MVA for symmetrical short circuits. Circuit breaker capacity. 3|Page

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SWITCHGEAR AND PROTECTIVE DEVICES 2015 BOOKS [1]. Van C Warrington, “Protective Relays” Vol.-I & II [2]. Ravindranath, M.Chander, “Power System Protection and SwitchGear”, Wiley Eastern Ltd. New Delhi [3]. T S Madhav Rao, “Power System Protection”, TMH Pulication [4]. Sunil S.Rao, “Switch Gear and Protection”, Khanna Publication 4|Page