Define operating time of … Naturally the primary protection is the first to operate, it’s operating time being less than that of the back-up relay. What are the main functions of Differential Relays? Question2: Difference between Switched Virtual Circuits (SVCs) and Permanent Virtual Circuits (PVCs)? Interview. It is inverse in the sense, the tripping time will decrease as the magnitude of fault current increase. Why biased differential protection is preferred over simple differential protection? A. Shunt Faults: Basically shunt faults are short circuits. This website uses cookies to improve your experience. A. Inverse Time Over-current Relay. An over-current (OC) relay has a single input in the form of ac current. During abnormal & faulty conditions (when current exceeds the rated value) an arc is produced between the fixed & moving contacts & thereby it forms the open circuit arc is extinguished by the Arc Quenching media like air, oil, vacuum etc. Distance relay is superior to overcurrent protection for the protection of transmission lines. It refers to the current or voltage which is used to activate the relay into operation. A CT whose primary is in series with the line in which current is to be measured. A. By preparing answers for these common interview questions, you can develop compelling talking points to make a great impression during your next job interview. A relay must get an adequate chance to protect the zone under its primary protection. Directional relay is used when graded time overload protection is applied to ring mains and interconnected networks. 78% of relaying is still electromechanical. Question 2. With an additional 53 professionally written interview answer examples. 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. Oil Circuit Breaker 3. What are soft skills interview questions? Define energizing quantity. Air Break Circuit Breaker 2. It is a differential relay where the operating current required to trip can be expressed as a percentage of load current. 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. Interview Questions; Frame Relay; 6. It is an inverse definite minimum time 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. Section 2: Electrical Interview Questions and Answers About Operating Principles and Relay Characteristics. A. A. See a list of common communication skills interview questions. 0. Vacuum Circuit Breaker 6. Buchholz relay provides protection only against transformer internal fault. The current transformer has two jobs to do. A. A. What Is The Operation Principle Of Differential Relay? Thus fuses are used for only once but breakers can used by multiple number of times. Think of DLCIs as the MAC address of the Frame Relay network. What is protective relay? Where Impedance relay, Reactance relay, and Mho relays are employed? Soft skills include things like communication, work ethic, time management skills, etc. What is the Power plant or Power Station? What is reverse power relay? The circuit breaker is an electrically operated switch, which is capable of safely making, as well as breaking, short-circuit currents. A. Answer : Behavioral Interview Questions. What is the need of relay coordination? The generation, distribution, and transmission system … Here’s how to answer the 16 most common interview questions: Did you also work with Electromechanical relays? The relay has two settings. 300+ TOP Protection Relay Engineer Interview Questions [UPDATED] Question 1. Thus the pick-up value of the relay should be more than the allowable maximum load. DLCIs have local significance. 250+ Frame Relay Interview Questions and Answers, Question1: Protocol of Frame Relay rely on for error checking? A. Fuses are burnt when over current flows in the circuit but circuit breakers will just open during over current. Question3: At what layers of the OSI model does Frame Relay operate? For what type of fault does Buchholz relay is employed? Plug Setting Multiplier and is defined as the ratio of fault current in the relay coil to the pick-up value. Bharadwaj. Explain The Encapsulation Types Of Frame Relay? Contacted for a phone interview followed by a skype interview with a number of team members. 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. Explain the working of an Over current relay and mention the types of it? We tracked down the 10 most-asked interview questions by analysing our Interview Builder tool that employers and recruiters use. So, they have very short arcing time and can interrupt high currents. 1. Series Faults: Series faults are nothing but a break in the path of current. Study the electrical engineering technical questions and answers on protection relays to prepare for the job discussions. Here are some important Windows Server Interview Questions for fresher and experienced candidate both. Question4: What is a Data Link Connection Identifier (DLCI)? Primary winding of a current CT which is connected in series with the line to be protected. The process took 2 weeks. In the above figure, the relay circuit is divided into three parts. Soft skills interview questions aim to reveal how strong a candidate's soft skills are before a hiring decision is made. Where does Negative phase sequence relay is employed? It has two contacts namely fixed contact & moving contact. Negative sequence relay is employed for the protection of generators and motors against unbalanced loading that may arise due to phase to phase faults. 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. Where does the Negative phase sequence relay is employed? 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. 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. Firstly, it steps down the current to such a level that it can be easily handled by the relay current coil. If SF6 (Sulpher Hexa Fluoride) gas is used as arc quenching medium in a Circuit breaker, it is termed as SF6 CB. 23. 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 differential relay operates when the phasor difference of two or more similar electrical quantities exceeds a pre-determined amount. If not, … 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. The relay has two settings. Question 5. Why distance protection is preferred as primary protection compared to overcurrent protection for transmission lines? 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? These questions require you to provide an example from your past work experiences. 22. b. Protection Relays Interview Questions & Answers Where does the Negative phase sequence relay is employed? As you prepare for your interview, you may be considering which questions the employer is going to ask you. No real technical question but they asked me to submit a piece of code that I had written. Q. differential relay operates when the phasor … A. IDMT relays have better fault clearing times over DTOC relays. 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. Define IDMT relay? current transformer interview questions and answers is very important for electrical graduates. Can we measure over voltage and over current by measuring current only? Thus, the pick-up value should be less than the smallest fault current. 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. 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). At the same time, the relay should be sensitive enough to respond to the smallest fault. Electric Interview Questions In Relay . 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 Ehv system steps down the current required to trip can be easily handled by the Microsoft Corporation protection is committed... Me to submit a piece of code that I had written communication skills interview Questions to... 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