It is an inverse definite minimum time relay. 1. A. IDMT relays have better fault clearing times over DTOC relays. What different kind of relaying you have worked with? Where Impedance relay, Reactance relay, and Mho relays are employed? A. The instantaneous type attraction armature can be made a definite time lag or inverse time lag by using an oil dashpot, an air escapement chamber a clockwork mechanism or by placing a fuse in parallel with it. Normal, Alert, Emergency, In extremis and Restorative. While there’s no way to know for sure what topics will be covered, there are several popular interview questions you can expect to be asked. A. Isolators are mainly for switching purpose under normal conditions but they cannot operate in fault conditions. Did you also work with Electromechanical relays? Negative sequence relay is employed for the protection of generators and motors against unbalanced loading that may arise due to phase to phase faults. The time setting decides the operating time of the relay while the plug setting decides the current required for the relay to pick up. DLCIs have local significance. Refer to the diagram below to answer Question 5 to Question 8 Q5. Negative sequence relay is employed for the protection of generators and motors against unbalanced loading that may arise due to phase to phase faults. Inverse Time Over-current Relay. Dear Readers, Welcome to Switchgear Protection Interview Questions and Answers have been designed specially to get you acquainted with the nature of questions you may encounter during your Job interview for the subject of Switchgear Protection.These Switchgear Protection Questions are very important for campus placement test and … In this article, we share some of the most commonly asked interview questions with tips on what interviewers are looking for in your response and example answers. Thus, the pick-up value should be less than the smallest fault current. A. A. Shunt Faults: Basically shunt faults are short circuits. Why distance protection is preferred as primary protection compared to overcurrent protection for transmission lines? Plug Setting Multiplier and is defined as the ratio of fault current in the relay coil to the pick-up value. Explain the working of an Over current relay and mention the types of it? By preparing answers for these common interview questions, you can develop compelling talking points to make a great impression during your next job interview. The generation, distribution, and transmission system … differential relay operates when the phasor … If they got excellent grades, this will be easy to answer. Define operating time of … Answer: The Impedance relay is suitable for the phase faults relaying for the lines of moderate lengths Reactance type relays are employed for the ground faults while Mho type of relays are best suited for the long transmission lines and particularly where synchronizing power surge may occur What is percentage differential relay? Question 5. A. What is the Power plant or Power Station? Explain The Encapsulation Types Of Frame Relay? Relay interview details: 1 interview questions and 1 interview reviews posted anonymously by Relay interview candidates. Can we measure over voltage and over current by measuring current only? The CIR is the committed information rate, by the service provider, in bits per second, at which data will be transferred. Question2: Difference between Switched Virtual Circuits (SVCs) and Permanent Virtual Circuits (PVCs)? We can set the pick-up value of the relay, keeping in mind that the relay should allow normal load as well as a certain degree of overload to be supplied. 0. Reverse Power flow relay are used to stop the flow of power from grid to station generator when the generating units are off. Contacted for a phone interview followed by a skype interview with a number of team members. What are the main functions of Differential Relays? What Is The Operation Principle Of Differential Relay? Networking Tutorial. Distance relay is superior to overcurrent protection for the protection of transmission lines. Q. What grades did you get in college? What Are The Bandwidth Specifications Of Frame Relay? What does the first part consist of? Encapsulation types of Frame Relay : Cisco and IETF (Internet Engineering Task Force) 7. Induction type non-directional over current relay,Induction type directional over current relay & current differential relay. Browse from thousands of Electrical questions and answers (Q&A). d. All of these. Under normal conditions the moving contact comes in contact with fixed contact thereby forming the closed contact for the flow of current. The operation of a relay should be fast and selective, ie, it should isolate the fault in the shortest possible time causing minimum disturbance to … Name the different kinds of over current relays. Best Switchgear Protection Interview Questions and Answers. Windows Server Interview Questions: Windows Server is a series of different server operating systems that have been developed by the Microsoft Corporation. Define energizing quantity. A relay must get an adequate chance to protect the zone under its primary protection. Air Blast Circuit Breaker 5. 78% of relaying is still electromechanical. The circuit breaker is an electrically operated switch, which is capable of safely making, as well as breaking, short-circuit currents. With an additional 53 professionally written interview answer examples. These questions require you to provide an example from your past work experiences. The process took 2 weeks. Only if the primary protection does not clear the fault, the back-up protection should initiate tripping. The voltage transformer or potential transformer steps down the high voltage of the line to a level safe enough for the relaying system (pressure coil of relay) and personnel to handle. Answer : Access Rate; Committed Information Rate; Voice Over Internet Protocol (VOIP) Interview Questions . Review this list of 15 questions and answers to help you prepare for your next interview. So, they have very short arcing time and can interrupt high currents. Firstly, it steps down the current to such a level that it can be easily handled by the relay current coil. If you're preparing for a customer service job interview, it can be helpful to review frequently asked questions and answers ahead of time so you have some idea of what to expect. Where does Negative phase sequence relay is employed? a. What are soft skills interview questions? Thus the pick-up value of the relay should be more than the allowable maximum load. Types: 1. Minimum Oil Circuit Breaker 4. SF6 Circuit Breaker. Section 2: Electrical Interview Questions and Answers About Operating Principles and Relay Characteristics. At the same time, the relay should be sensitive enough to respond to the smallest fault. A. Multiple Choice Question (MCQ) of Protective Relays page-4; Multiple Choice Question (MCQ) of Protective Relays page-3; Multiple Choice Question (MCQ) of Protective Relays page-2; Multiple Choice Question (MCQ) of Protective Relays page-1; Multiple Choice Question (MCQ) of Fuse; Multiple Choice Question (MCQ) of Circuit Breaker page-3 Vacuum Circuit Breaker 6. Whereas CB gets activated under fault conditions according to the fault detected. Series Faults: Series faults are nothing but a break in the path of current. Protection Relays Interview Questions & Answers . Bharadwaj. Save my name, email, and website in this browser for the next time I comment. What is the operation principle of the differential relay? Foundation Fieldbus Interview Questions and Answers, Electrical Cables Interview Questions & Answers, Transmission and Distribution Interview Questions, Electric Drives and Traction Interview Questions, High Voltage and Power System Stability Interview Questions, Power Electronics Interview Questions Part-1, Transformers Interview Questions & Answers, What is FAT and SAT? Generator Protection Interview Questions; Protection Relays Interview Questions; Neutral Grounding in Power System; Answer: Basic fundamental elements of the relay are: Sensing element: It is the measuring element measures the actuating quantity. b. Interview. c. Tripping circuit. EelectricalLive.com | 2015-2020 | Contact US, Interview Question On Circuit Breaker And Relay, Torque-Slip Characteristics In Three Phase Induction Motor. A. Question 2. Practice 27 Global Relay Communications, Inc. Interview Questions with professional interview answer examples with advice on how to answer each question. Process lasted around 2 weeks. Study the electrical engineering technical questions and answers on protection relays to prepare for the job discussions. When voltage increases then current also increases then what is the need of over voltage relay and over current relay? Protection Relays Interview Questions & Answers Where does the Negative phase sequence relay is employed? A. A. A. current transformer interview questions and answers is very important for electrical graduates. Air Break Circuit Breaker 2. For example, an interviewer might ask, “Tell me about a time you … We have to allow for the overshoot of the primary relay, so that there is proper coordination between the primary and the back-up. This website uses cookies to improve your experience. If SF6 (Sulpher Hexa Fluoride) gas is used as arc quenching medium in a Circuit breaker, it is termed as SF6 CB. The output of the relay is a normally-open contact, which changes over to closed state when the relay trips. Secondary of the CT and the operating coil. In addition to job-specific interview questions, you will also be asked more general questions about your employment history, education, strengths, weaknesses, achievements, goals, and plans. A. Think of DLCIs as the MAC address of the Frame Relay network. Instantaneous Over-current Relay 2. Soft skills include things like communication, work ethic, time management skills, etc. I interviewed at Relay Therapeutics in February 2020. I don't leave many remarks, but i did some searching and wound up here "Interview Questions on Transformer Protection". Then we asked Steve Shepard, CEO of TwoPointZero and Suzie McInerney, CEO of Six Degrees Executive to take us through why employers ask each question and explain what they look for in a response. Here are some very important current transformer interview questions with proper answers which are mostly asked with Electrical Graduates in every industrial interview as … Learn Windows Server Interview Questions and answer cracks the interview. Multiple Choice Question (MCQ) of Protective Relays page-4; Multiple Choice Question (MCQ) of Protective Relays page-3; Multiple Choice Question (MCQ) of Protective Relays page-2; Multiple Choice Question (MCQ) of Protective Relays page-1; Multiple Choice Question (MCQ) of Fuse; Multiple Choice Question (MCQ) of Circuit Breaker page-3 A PT primary is connected in parallel at the point where a measurement is desired. Differential Relays must have the following features: Relay settings mean the actual value of the energizing or characteristic quantity at which the relay is designed to operate under given conditions. A differential relay operates when the phasor difference of two or more similar electrical quantities exceeds a pre-determined amount. What is the operation principle of the differential relay? What is the percentage differential relay? Q. It is observed in practice that most of the open conductor faults sooner or later develop into some or the other short-circuit fault. 300+ TOP Protection Relay Engineer Interview Questions [UPDATED] Question 1. In an IDMT (inverse definite minimum time) relay, the operating principle is based on the idea that with the more severe a fault is, the faster it should be cleared to avoid damage to the apparatus. An over-current (OC) relay has a single input in the form of ac current. SF6 gas has superior arc quenching capacity and high dielectric strength. 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. A. Fuses are burnt when over current flows in the circuit but circuit breakers will just open during over current. The farthest point from the relay location, which is still inside the zone of protection, is called the reach point. A. Oil Circuit Breaker 3. Why biased differential protection is preferred over simple differential protection? The team was very welcoming and friendly. An over-current (OC) relay has a single input in the form of ac current. A. For what type of fault does Buchholz relay is employed? Where Impedance relay, Reactance relay, Reactance relay, Induction type directional over current &. Level that it can be expressed as a percentage of load current almost same conditions but they can not in! 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