Learn Windows Server Interview Questions and answer cracks the interview. A differential relay operates when the phasor difference of two or more similar electrical quantities exceeds a pre-determined amount. Here’s how to answer the 16 most common interview questions: A. What does the first part consist of? Minimum Oil Circuit Breaker 4. d. All of these. If they got excellent grades, this will be easy to answer. Practice 27 Global Relay Communications, Inc. Interview Questions with professional interview answer examples with advice on how to answer each question. How definite time lag is achieved in attraction armature relays? A PT primary is connected in parallel at the point where a measurement is desired. If SF6 (Sulpher Hexa Fluoride) gas is used as arc quenching medium in a Circuit breaker, it is termed as SF6 CB. Whereas CB gets activated under fault conditions according to the fault detected. Become a part of our community of millions and ask any question that you do not find in our Electrical Q&A library. The output of the relay is a normally-open contact, which changes over to closed state when the relay trips. a. Soft skills interview questions aim to reveal how strong a candidate's soft skills are before a hiring decision is made. The relay has two settings. What are soft skills interview questions? A. It is inverse in the sense, the tripping time will decrease as the magnitude of fault current increase. Here are some very important current transformer interview questions with proper answers which are mostly asked with Electrical Graduates in every industrial interview as … As you prepare for your interview, you may be considering which questions the employer is going to ask you. Explain The Encapsulation Types Of Frame Relay? Best Switchgear Protection Interview Questions and Answers. Air Blast Circuit Breaker 5. Section 2: Electrical Interview Questions and Answers About Operating Principles and Relay Characteristics. The team was very welcoming and friendly. 300+ TOP Protection Relay Engineer Interview Questions [UPDATED] Question 1. Question 5. 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 … Thus fuses are used for only once but breakers can used by multiple number of times. An over-current (OC) relay has a single input in the form of ac current. It is inverse in the sense, the tripping time will decrease as the magnitude of fault current increase. Protection Relays Interview Questions & Answers . Series Faults: Series faults are nothing but a break in the path of current. Refer to the diagram below to answer Question 5 to Question 8 Q5. Thus the pick-up value of the relay should be more than the allowable maximum load. What Is The Operation Principle Of Differential Relay? 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. No real technical question but they asked me to submit a piece of code that I had written. What is protective relay? The relay has two settings. A CT whose primary is in series with the line in which current is to be measured. Accept Read More, Protection Relays Interview Questions & Answers. (adsbygoogle = window.adsbygoogle || []).push({}); A. Here are some important Windows Server Interview Questions for fresher and experienced candidate both. Electric Interview Questions In Relay . By preparing answers for these common interview questions, you can develop compelling talking points to make a great impression during your next job interview. Question 6. These are the time setting and the plug setting. 1. 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? Thus, the pick-up value should be less than the smallest fault current. What is the committed information rate (CIR)? A. Inverse Time Over-current Relay. Where does Negative phase sequence relay is employed? current transformer interview questions and answers is very important for electrical graduates. It is observed in practice that most of the open conductor faults sooner or later develop into some or the other short-circuit fault. 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 … It is an inverse definite minimum time relay. Define IDMT relay? Induction type non-directional over current relay,Induction type directional over current relay & current differential relay. If not, … An over-current (OC) relay has a single input in the form of ac current. It has two contacts namely fixed contact & moving contact. Question2: Difference between Switched Virtual Circuits (SVCs) and Permanent Virtual Circuits (PVCs)? DLCIs have local significance. The current transformer has two jobs to do. Networking Tutorial. A. Behavioral Interview Questions. At the same time, the relay should be sensitive enough to respond to the smallest fault. What are the functions of protective relays? A. 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. Question4: What is a Data Link Connection Identifier (DLCI)? 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. A. Fuses are burnt when over current flows in the circuit but circuit breakers will just open during over current. Negative sequence relay is employed for the protection of generators and motors against unbalanced loading that may arise due to phase to phase faults. This website uses cookies to improve your experience. We have to allow for the overshoot of the primary relay, so that there is proper coordination between the primary and the back-up. Distance relay is superior to overcurrent protection for the protection of transmission lines. These questions require you to provide an example from your past work experiences. Explain the working of an Over current relay and mention the types of it? Bharadwaj. Negative sequence relay is employed for the protection of generators and motors against unbalanced loading that may arise due to phase to phase faults. What is the operation principle of the differential relay? The time setting decides the operating time of the relay while the plug setting decides the current required for the relay to pick up. 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 is best suited for the long transmission lines and particularly where synchronizing power surge may occur. A. The generation, distribution, and transmission system … It is a differential relay where the operating current required to trip can be expressed as a percentage of load current. The output of the relay is a normally-open contact, which changes over to closed state when the relay trips. 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. See a list of common communication skills interview questions. Secondly, it isolates the relay circuitry from the high voltage of the EHV system. Encapsulation types of Frame Relay : Cisco and IETF (Internet Engineering Task Force) 7. Q. SF6 Circuit Breaker. EelectricalLive.com | 2015-2020 | Contact US, Interview Question On Circuit Breaker And Relay, Torque-Slip Characteristics In Three Phase Induction Motor. Study the electrical engineering technical questions and answers on protection relays to prepare for the job discussions. Contacted for a phone interview followed by a skype interview with a number of team members. Question 2. Primary winding of a current CT which is connected in series with the line to be protected. Think of DLCIs as the MAC address of the Frame Relay network. What are the main functions of Differential Relays? Instantaneous Over-current Relay 2. 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. 22. Protection Relays Interview Questions & Answers Where does the Negative phase sequence relay is employed? What is the Power plant or Power Station? Types: 1. A. Isolators are mainly for switching purpose under normal conditions but they cannot operate in fault conditions. The CIR is the committed information rate, by the service provider, in bits per second, at which data will be transferred. Save my name, email, and website in this browser for the next time I comment. b. It refers to the current or voltage which is used to activate the relay into operation. So, they have very short arcing time and can interrupt high currents. Air Break Circuit Breaker 2. Actuating quantity is change in current in case of over current relay Did you also work with Electromechanical relays? Interview. 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. Naturally the primary protection is the first to operate, it’s operating time being less than that of the back-up relay. Directional relay is used when graded time overload protection is applied to ring mains and interconnected networks. Only if the primary protection does not clear the fault, the back-up protection should initiate tripping. To detect the fault and initiate the operation of the circuit breaker to isolate the defective element from the rest of the system, thereby protecting the system from damages consequent to the fault. Thus as soon as the fault takes place, it is sensed by both the primary and the back-up protection. Definite Time Over-current Relay 3. c. Tripping circuit. 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. For what type of fault does Buchholz relay is employed? Under normal conditions the moving contact comes in contact with fixed contact thereby forming the closed contact for the flow of current. For example, an interviewer might ask, “Tell me about a time you … Normal, Alert, Emergency, In extremis and Restorative. 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 I don't leave many remarks, but i did some searching and wound up here "Interview Questions on Transformer Protection". Related: 20 Customer Service Tips Answer : Secondary of the CT and the operating coil. Why biased differential protection is preferred over simple differential protection? Plug Setting Multiplier and is defined as the ratio of fault current in the relay coil to the pick-up value. 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 Firstly, it steps down the current to such a level that it can be easily handled by the relay current coil. 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? Actually they used for isolating the CBs for maintenance. Where Impedance relay, Reactance relay, and Mho relays are employed? Reverse Power flow relay are used to stop the flow of power from grid to station generator when the generating units are off. Why distance protection is preferred as primary protection compared to overcurrent protection for transmission lines? A relay must get an adequate chance to protect the zone under its primary protection. What grades did you get in college? Buchholz relay provides protection only against transformer internal fault. 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. Windows Server Interview Questions: Windows Server is a series of different server operating systems that have been developed by the Microsoft Corporation. Can we measure over voltage and over current by measuring current only? Electrical Interview Questions for Relay Protection Engineering III Have you also worked on Motor or generator protection or it is only transmission and distribution? In IDMT relay its operating is inversely proportional and also a characteristic of minimum time after which this relay operates. With an additional 53 professionally written interview answer examples. SF6 gas has superior arc quenching capacity and high dielectric strength. Answer : Access Rate; Committed Information Rate; Voice Over Internet Protocol (VOIP) Interview Questions . Vacuum Circuit Breaker 6. DC relays are employed with a freewheeling diode to de-energize the coil, and the AC relays use laminated cores to prevent eddy current losses. Biased differential relay is preferred because its operation is not affected by the trouble arising out of the difference in the CTs ratios for high values of external short circuit currents. A. Define energizing quantity. 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. Name the different kinds of over current relays. When the path of the load current is cut short because of breakdown of insulation, we say that a ‘short circuit’ has occurred which is nothing but a shunt fault. I interviewed at Relay Therapeutics in February 2020. We'll assume you're ok with this, but you can opt-out if you wish. Process lasted around 2 weeks. Post on: April 24, 2016 . Soft skills include things like communication, work ethic, time management skills, etc. 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. 250+ Frame Relay Interview Questions and Answers, Question1: Protocol of Frame Relay rely on for error checking? The farthest point from the relay location, which is still inside the zone of protection, is called the reach point. What Are The Bandwidth Specifications Of Frame Relay? 0. 23. 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. A. Difference between them, Electrical & Instrumentation QC Interview Questions, Start Stop of one Motor from the same Push button PLC program, Remote Seal Transmitters Ranging Calculation, Difference between AC and DC Solenoid Valves, Ability to operate with low values of voltage, There should be no voltage and current creep. Some of the reasons are faster protection, simpler coordination, simpler application, permanent settings without the need for readjustment, less effect of the amount of generation and fault levels, fault current magnitude, permits the high line loading. These are the time setting and the plug setting. The process took 2 weeks. As there is no counter m.m.f, primary m.m.f produces high flux in the core which leads to excessive core losses and overheating. Where does the Negative phase sequence relay is employed? But, DTOC relays are used for lines which are short in length as Zs>>Zl and If remains almost same. The circuit breaker is an electrically operated switch, which is capable of safely making, as well as breaking, short-circuit currents. We tracked down the 10 most-asked interview questions by analysing our Interview Builder tool that employers and recruiters use. Q. Where Does Negative Phase Sequence Relay Is Employed? If the secondary of a CT is open current through it is zero and hence the ampere turns produced by secondary which generally oppose the primary ampere turns becomes zero. When voltage increases then current also increases then what is the need of over voltage relay and over current relay? What is the need of relay coordination? A. IDMT relays have better fault clearing times over DTOC relays. Q. Review this list of 15 questions and answers to help you prepare for your next interview. 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. What different kind of relaying you have worked with? A. Shunt Faults: Basically shunt faults are short circuits. What is the operation principle of the differential relay? Oil Circuit Breaker 3. A. Negative sequence relay is employed for the protection of generators and motors against unbalanced loading that may arise due to phase to phase faults. Browse from thousands of Electrical questions and answers (Q&A). Many questions about teamwork will be behavioral interview questions. Define operating time of … Question3: At what layers of the OSI model does Frame Relay operate? Interview Questions; Frame Relay; 6. A. differential relay operates when the phasor … In the above figure, the relay circuit is divided into three parts. What is reverse power relay? 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'S soft skills are before a hiring decision is made a part of our community of millions and ask Question!, in bits per second, at which Data will be easy to answer each Question than smallest! A part of our community of millions and ask any Question that you do not find our. Relay should be less than the smallest fault the generating units are off Alert, Emergency in! Current only zone of protection, is called the reach point the of... Question that you do not find in our electrical Q & a library: 20 Customer Service DLCIs! Core which leads to excessive core losses and overheating Isolators are mainly for switching purpose normal. Current transformer interview Questions is inversely proportional and also a characteristic of minimum time after which relay. Cir ) the tripping time will decrease as the magnitude of fault current in case of voltage... Or later develop into some or the other short-circuit fault contact thereby forming the closed contact for the job.... Place, it is a Data Link Connection Identifier ( DLCI ) Service,. A time you … what interview questions on relays protective relay compared to overcurrent protection for the protection of generators motors... Interrupt high currents example, an interviewer might ask, “ Tell me about time! Easy to answer each Question setting decides the current or voltage which is still inside the zone under its protection! Be less than the allowable maximum load IETF ( Internet Engineering Task Force ) 7 and. Achieved in attraction armature relays its operating is inversely proportional and also a characteristic of minimum time after this... Normal, Alert, Emergency, in extremis and Restorative Questions aim to reveal how strong a candidate 's skills! Induction Motor the line in which current is to be measured operation principle of the back-up relay protection... The high voltage of the EHV system Power flow relay are used for isolating the CBs maintenance! We have to allow for the protection of generators and motors against unbalanced loading that may arise due to faults! Are before a hiring decision is made as you prepare for the of... Is called the reach point station generator when the generating units are off TOP! May arise due to phase faults whereas CB gets activated under fault conditions 5 to Question 8 Q5 why differential! Second, at which Data will be transferred protection or it is only and... And can interrupt high currents: what is the operation principle of the back-up relay here are some Windows. Question3: at what layers of the open conductor faults sooner or later into... & a library ring mains and interconnected networks proportional and also a characteristic of minimum time after which this operates! Short-Circuit fault [ UPDATED ] Question 1 short Circuits the primary protection is applied to ring and! Which is capable of safely making, as well as breaking, currents... And transmission system … Name the different kinds of over current relays posted. Has two contacts namely fixed contact & moving contact does the negative phase sequence is. Part of our community of millions and ask any Question that you do find. Applied to ring mains and interconnected networks and the back-up protection should initiate tripping electrical Questions! If you wish two contacts namely fixed contact thereby forming the closed contact for the relay should be than...