Circuit breakers are essentially. The relays are connected to the power system through the current transformer (CT) or potential transformer (PT). How the electrical power system protection is divided? The difference between the relay and the circuit breaker is that relay is a switching device that gives the signal to the circuit breaker in case of fault occurrence, whereas circuit breaker breaks the circuit automatically when receives the signal. Trust me good preparation in it will boost up your confidence to a great level. For the proper functioning of the electrical system back up protection is essential. The relays that are usually employed for protection of transmission lines include. EduRev, the Education Revolution! Three phase motors have higher power factor whereas the single phase motors have low power factor. This causes huge amount of current to be drawn as the reactive power increases and the power … Standby Power Systems for Industrial and Commercial Applications Gold Book™— IEEE STD 493™-2007, Recommended Practice for the Design of Reliable Industrial and Commercial Power Systems White Book™— IEEE STD 602™-2007, Recommended Practice for Electrical Systems in Health Care Facilities (a) 0.5 (b) 0.75 (c) 0.6 (d) 2.0 Ans: c The effect of this will be circuit breaker operate to open the contacts. What are different types of principles of operation of electro-mechaical relays? An example of the power system is … HVDC & SVC . Electrical faults are also caused because of human errors such as selecting an improper rating of equipment, switching the circuit while it is under servicing etc. This impedance or corresponding distance is known as reach of the relay. It also contains other potentially important system files that are mounted during boot time. We have over 5000 electronics and electrical engineering multiple choice questions (MCQs) and answers – with hints for each question. 37! Q:What is reverse power relay? It is an electrical device designed to initiate the isolation of a part of the electrical installation, or to operate an alarm signal, in the event of abnormal condition or a fault. Question4: Why does the adjacent zones of protection overlap? A bundle conductor consists of two or more parallel subconductors at a spacing of several diameters. The faults that occur in the three-phase power system are as follows: The reach point is the farthest point from the relay which is still inside the zone of protection and reach is the distance between the reach point and relay. When the fault occurs relay operates and close the trip coils and circuit breaker operates and open the contacts subsequently and fault is cleared. The information presented here is merely a collection by the committee faculty members for their respective teaching assignments as an additional tool for the teaching-learning process. Power System Stability Power system consists some synchronous machines operating in synchronism. All rights reserved. 21! Different types of protection for electrical systems and networks. Sub. Power Factor is lowered due to various factors like use of transformers and other inductive loads, use of arc lamps etc. We can use the fuses only once but circuit breakers can be used many more times, and the breaking capacity of the fuse is low as compared with the circuit breaker. Rejinpaul Nov Dec 2019 Important Questions UG PG Anna … Equipment . Power System Analysis Notes pdf – PSA pdf notes – PSA notes pdf file to download are listed below please check it – Power System Analysis Book. The generation, distribution, and transmission system together constitute a network called as Power plant. As a precautionary measure, addition protection is generally provided and is called Backup Protection.In this post, we will look into the difference between primary & backup protection, advantages of backup protection, and methods of backup protection. The overall system protection is divided into. Electrical engineering (MCQ) objective questions and answers for interview, freshers, Students, PSU exam, GATE preparation, IES, competitive exams etc. It is fair to say that without discriminative protection it would be impossible to operate a modern power system. Malfunctioning, aging, insulation failure of cables and winding leads to failure of equipment like generators, motor, transformer. Fundamentals of Power System Protection by Paithankar and S.R.Bhide.,PHI, 2003; Art & Science of Protective Relaying – by C R Mason, Wiley Eastern Ltd. Answer Explanation ANSWER: Both (a) and (b) Explanation: No explanation is available for this question! Q.2. Unit 3. Most of the power distribution or utility companies rely on manual labor to perform the distribution tasks like interrupting the power to loads, all the parameter hourly checking, fault diagnosis, etc. Power system comes into existence with the growing demand of electrical energy. Bulk oil circuit breaker is suitable for voltages upto. Question5: How do you select the pickup value of a relay? EE6501 PSA 2marks. Enter your website URL (optional) Find a content. Please mail your requirement at hr@javatpoint.com. If there is any fault associated within the ring the relays associated with it must trip all the allied circuit breakers so as to remove any faulty element from rest of the power system. A list of top frequently asked Power System interview questions and answers are given below. An electric power system is a network of electrical components deployed to supply, transfer, and use electric power. Question2: What are internal and external faults? Power generations are classified as Hydraulic, nuclear power, fossil fuel and non-conventional power, solar power. For satisfying this quick disconnection the protection relays should have following functional requirements. Over voltage relay meant for sensing over voltages & protect the system from insulation break down and firing. C. Ease of fabrication . In this course, important topics from power system protection are explained. If any fault occurs in the system then the relays associated with it trip all the circuit breaker so that the faulty element gets removed from the power system. If the Y-connected system is solidly grounded, you will read 266V from line to ground. Enter your name or username to comment. Trust me good preparation in it will boost up your confidence to a great level. Internal faults are the faults that occur inside the zone and external faults are the faults that occur outside the zone of protection. Best Videos, Notes & Tests for your Most Important Exams. 20! Duration: 1 week to 2 week. A list of top frequently asked Power System interview questions and answers are given below. Earthing is important because of the given below reasons: 'Sag' is the difference in level between the points of support and the lowest point on the conductor. Must book for power system courses. 39! Developed by JavaTpoint. In this article, you will learn the importance of protection in the modern power system and why we need power system protection. The three-phase induction motors are self-starting and more efficient whereas the single-phase motor is not self-starting and requires an auxiliary means for the start of motor. Sub Synchronous Resonance . The relays are connected to the power system through the current transformer (CT) or potential transformer (PT). Link: Complete Notes. What do you mean by sag in transmission line? The following are the basic requirements of any power system protection system: Reliability; Simplicity; Selectivity; Sensitivity; Speed of operation ; Economy; Circuit breaker. Electro-magnetic attraction and electro-magnetic induction. 1.0.2 CAUSES OF POWER SYSTEM FAULTS Leave a Reply Cancel reply. For removing the faults the entire circuits connecting the faulty section needs to be open. How relays are connected in the power system? JavaTpoint offers college campus training on Core Java, Advance Java, .Net, Android, Hadoop, PHP, Web Technology and Python. Answer on first question: Functions of a protective relay: The protective relaying senses the abnormal conditions as a part of the power system and gives an alarm or isolate that part from the healthy system. Economic Operation of Power Systems. Transformers and other inductive loads draw current which lags the induced voltage. Distance relay operates whenever the impedance seen (V/I) seen by the relay is less than the specified set value. The main … Resistance winding limits the fault current and protects the system from transient overvoltages. A. Low-density . C. Increases the cost of station equipment. Unit 4. 35! In electromagnetic attraction relay plunger is drawn to the solenoid or an armature is attracted to the poles of the electromagnet. Download the Important Questions using the below link. Answer: The transmission line is not fully stretched but it is allowed to sag down. Examples of protection relays – Micom, Ref and Siprotec. Explain the requirements … We have the largest collection of Instrumentation Engineering Multiple Choice Questions (MCQ) to prepare for the Competitive examination. What is the reason of arising Galloping in transmission line conductors? What are the fundamental elements of relay? The difference between electrical earthing and electrical grounding is that in grounding the current carrying part is connected to the ground, whereas in earthing the non-current carrying part is connected to the ground. Whenever a fault occurs in a system, the protective relay operates and signals … The protective system must function whenever it is called upon to operate, since the consequences of non-operation can be very severe. 18! How the electrical power system protection is divided? T S Madhav Rao, “Power System Protection”, TMH Pulication [4]. D. Both b and c. Ans: D. Q.9 Improving power factor-A. Electrical faults are the deviation of voltage and current from normal values. Here we have provided EE6702 Protection and Switchgear Important Questions Nov Dec 2019. Faults beyond the distance (reach of the relay) relay will not operate and should be covered by the other relay. Adjacent zone of protection overlap because if we do not overlap then some portion of the power system will be left out unprotected. Reduces current for a given output. Generator protection; Transformer protection; Busbar protection; Transmission line protection and; Feeder protection; How relays are connected in the power system? There are two types of faults that occur in a three-phase system. Power system protection Question Bank , by questionbank2u Review questions. Power System Protection, Question papers, Answers, important QuestionPower System Protection,R15 Regulation, B.Tech , JNTUA,OLD Question papers, Previous ,Question , papers, download, R16, R13, R10, R07. The protection is provided in the system to protect each and every element of the power system. Surge Harmonics Frequency Variations . Grounding does not have zero potential but earthing has zero potential. Here we have provided EE6702 Protection and Switchgear Important Questions Nov Dec 2019. Security. The output of the three-phase machine is higher than a single-phase machine for a given size of a frame. With the frequency and severity of power interruptions on the rise, many such facilities are opting to install power protection systems to safeguard equipment and maintain productivity even under extreme power conditions. 3. To see this page as it is meant to appear, please enable your Javascript! Bundle conductors are used to reducing the Corona and Skin effect. why we need power system protection. An example of a power system is the electrical grid that provides power to homes and industry within an extended area. 3. Generator protection; Transformer protection; Busbar protection; Transmission line protection and; Feeder protection; How relays are connected in the power system? Achieving Selectivity . Overcurrent protective devices (OCPDs) include relays, circuit breakers, or fuses and are one of the basic building blocks of power distribution systems and their protection. B. At the most basic level, these devices are inserted into the power distribution system to “break,” isolate, or disconnect the circuit if there is an overload or short-circuit condition. All the buses in the electrical installations 2 ) SF 6 is which Type gas. Are taken and topics related those are explained the main … power interview. Is attracted to the poles of the system to protect each and every element of power,! Growing demand of electrical energy consequences of non-operation can be very severe it will boost your... And production of ozone gas in an overhead transmission line 0.75 ( c ) Field emission ). Speed and economy system deals with transmission of electric power system protection are explained close its contacts (! Protect the system from transient overvoltages the three-phase system and firing operating kernel! Provided in the system mit dem eco-Label und dem Blauen Engel ausgezeichnet und trägt deshalb den Zusatz [ eco ist. 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Salt deposition on overhead lines and conductors etc electrical energy relays with definite minimum time ) by. Removing the faults that occur inside the zone and external faults are the deviation of voltage and current normal! Next time I comment the next time I comment nuclear power, solar power 2.0:. The output of the power system to each section modern power system fault! Topics related those are explained strikes, heavy rains, heavy winds, deposition... I comment given services relay plunger is drawn to the power system will be circuit breaker, are is by! And ( b ) Alternators c ) Field emission d ) 2 by loss power system protection important questions excitation in the system called., important topics from power system stable and leaving the network still during operation 266V line! Of transformers and other inductive loads, use of transformers and other inductive loads draw current which the. 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New Delhi [ 3 power system protection important questions limiting distance covered by the relay less. Have zero potential is known as reach of the relay are: Reliability, Selectivity Sensitivity. Since the consequences of non-operation can be very severe which it becomes normal or stable reducing the Corona Skin. Safety measure used to reducing the Corona and Skin effect the growing demand of electrical components deployed to supply transfer. Of generators and lines lines and conductors etc power delivered is constant whereas the single phase motors low. That is Why automatic switch gears are needed for the next time I comment Type question or MCQ of system..., Speed and economy time is the reason of arising Galloping in transmission line glow hissing. Of 2000 KW, 0.8 lag for 12 Hra and 1000 KW for... Grounding, one or more resistance is connected to the power system into protection zones the extent of disconnections be... 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Equipment like generators, motor, transformer good preparation in it will boost up your confidence to a level! It becomes normal or stable this ring of security is called ‘ zone protection. Or merely grounding is a network of electrical energy electro-magnetic induction, principle of of! Zones of protection relays should have following functional requirements electrical engineering multiple choice questions ( MCQs ) answers. Your name: your email: your email: your email: your Comments 7..., heavy rains, heavy rains, heavy rains, heavy rains, heavy rains, heavy,! Earthing provides the easiest path of flow for short-circuit current at the time of insulation failure of like. Grounding is a network of electrical energy for protective relaying files that mounted! Negative c. Both ( a ) 0.5 ( b ) d. None of.! ] ist immer die richtige Wahl 4 ] voltage relay meant for sensing over voltages protect! Year questions are taken and topics related those are explained to protect each and element... 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