Network Diagram showing the position of the transformer in the system 2. kVA or MVA rating of the transformer 3. That is electromagnetic induction between two circuits which is linked by a magnetic flux. Transformers MCQ question is the important chapter for a Electrical Engineering and GATE students. OverLoad ... increases copper losses and consequence temperature rise. Isolation transformer is a static machine used to isolate the two circuits and provides a magnetic coupling between two circuits. 3. Voltage transformers are usually connected between line and ground in which it is protected with the fuses. On-load tap changer is device which operates and changes the tap connection even when the transformer is supplying the load. 10 TOP Transformer Protection Interview Questions and Answers. Rectified Three phase signal gives less ripple factor compared single phase rectifier. In circuit where measurements of high voltage and high current is involved, they are used there. What is the impact if the 60 Hz transformer is operated at 50 Hz transformer? 11. Reverse Power flow relay are used in generating stations's protection. Answer: 1. Best Transformer Objective type Questions and Answers. Three phase motors for a given horsepower are smaller in physical size compared to single phase. These transformer interview questions is collected from various sources. I.e. 10 TOP Transformer Protection Interview Questions and Answers 1. Why taping is connected to high voltage side? When a load is connected to a transformer current (say I 2) flows through secondary coil thus an M.M.F (N 2 I 2) is produced, this produces the secondary flux. A transformer is a static device which can transfer power from one circuit … Requires less copper compared to single phase to transmit the same power. whenever any internal fault occurs in a transformer, the Buchholz relay at once gives a horn for some time, if the transformer is isolated from the circuit then it stop its sound itself otherwise it trips the circuit by its own tripping mechanism. What happens if the input voltage of the transformer is higher than name plate? (d) external short-circuits and overloads. So the power is same. Ans. The generation, distribution, and transmission system … Core saturation problem is not there in air core. 5. Home » Top 100 Switchgear and Protection Interview Questions. Interview Questions on Transformer Protection • Q. There are two types of cores air and iron. it can increase or decrease the output voltage a small bit because of one coil sharing. Where as in transformer there is no conversion of energy and hence no work done. What is the difference between transformer and amplifier? However, multiple things can go wrong with the transformer: There can be two types of failure - Internal Faults and External Faults. We will go on adding questions, till we reach 100 and may be we will add more than 100. What is difference between induction motor and transformer? Rated temperature (600): The maximum rated temperature that the transformer can be operated without any heating. The impedance of the transformer is the combination of resistance and reactance of the primary and secondary winding coils. 178. the voltage and current at the output can be changed by varying output windings to get the desired parameter at the output. Dry-type transformers are natural air-cooled transformers those are not oil-immersed. 1) Primary winding copper loss (I12R1), 2) Secondary winding copper loss (I22R2). Interview Questions on Transformer What is an equivalent circuit of a transformer? In a transformer the tappings are generally provided on. Winding Connections 6. b) Interfacial tension and acid number (sometimes called neutralization number or acidity) are affected by oxidation and contamination. Which of the following does not change in a transformer ? Automation Engineering Interview Questions. both quantities of the signal (voltage and current), increases in amplifier. (c) internal short-circuits. Earth fault protection is based on the method of neutral grounding; The system voltage during earth faults depends on the neutral grounding. What is a feedback in Control System? Electrical Interview Questions: Series-1 AE EXAM Bus coupler vs Interconnecting Transformer , Derived Earth Fault , Differences , Electrical , Interview , Measured Earth Fault , Neutral VS Ground Potential , Questions , Transformer VS Induction Motor It is generally rated above 200MVA. ... Download & View Transformer Interview Questions as PDF for free. These Transformer Protection Questions are very important for campus placement test and job interviews. Power System Protection Interview Questions. It consists three iron core legs on which the windings are mounted. Winding connection diagram: This diagram shows the primary and secondary winding connection diagram. Top 100+ Electrical Engineering Interview Questions and Answers - How to calculate VCB current rating for 2000 KVA transformer | Why CRGO material is used in transformer | What is AVR | Advantages of star-delta starter with induction motor | MCCB & ACB & VCB | KV, KVAR, KVA, KW | What is PTZ Camera | What is meant by AYFY Cable Automation Engineering Interview Questions. If the applied voltage is higher than 10% of rated voltage then transformer core saturation may occur. What is Marshalling Kiosk in power transformer a) It provides alarms, trips, controls and indications from main transformer b) It is the base on which transformer rail is provided to pull and push transformer c) It is the pressure device ruptures when temperature inside transformer increases d) None of the above. The main application of this type of transformer is in distribution side where as the transmitted high voltage has to be stepped down to distribute it for households purposes. Transformer oil functions as a coolant as well as insulating material. We have planned to give you 100 Interview Questions on Power Transformer. Read Free Transformer Interview Questions With Answers Electrical Transformer Interview Questions With Answers Electrical Yeah, reviewing a book transformer interview questions with answers electrical could be credited with your near links listings. The output of the CT will be normally 5 or 10 amps. Interview questions and answer examples and any other content may be used else where on the site. The increase in flux leads to core saturation. (c) IDMT relay. As the name specifies it provides only isolation, so the primary and secondary windings turns are same to ensure that there is no change in signal quantities like voltage and current. It also isolates the high voltage line and metering circuit to safe guard the metering circuit during a fault condition. Transformers are provided with bullet on (internal protections) for dielectric failure (formation of gas), temperature, oil pressure, level, winding temperature and on load tap changer. Best Transformer Protection Interview Questions and Answers. Table of Contents . It has better overload capacity than the oil-immersed transformers. Electrician Assistant Interview Questions . Amplifier: An electronic device which increases or boosts the power of the signal is called is an amplifier. The transformer taping connected generally to high voltage winding side because. Cooling class (ONAF): This indicates of type of cooling used in transformer. by Pranali N ... Power Transformer: 100 Interview Questions ! Fault current can damage the entire circuit. In low voltage winding the current flowing is high compared to high voltage winding ad hence I2R (core losses) losses are high which produces high heat. Step-up transformer is a transformer whose secondary voltage is higher than the primary voltage. When the leakage flux in a transformer increases, it will decrease the (a) ... INTERVIEW QUESTIONS. Interview question for GET in London, England.About transformer protection We will go on adding questions, till we reach 100 and may be we will add more than 100. Current Transformer (CT) is a step-up transformer which steps down the current to a known ratio. These are typically used between the two ends of transmission lines to step-up the voltage at the generating end of transmission line and to step down the voltage at the receiving end of the transmission side. Step down transformer is a voltage down transformer where the secondary voltage is less compared to primary voltage. Even though the signal quantities (voltage and current) can be boosted at the output, it cannot acts as amplifier because if one of the quantities is boosted at the output the other quantity is reduced. These transformers are also provides isolation between primary and secondary to limit the secondary fault current. TRANSFORMERS Multiple Choice Questions with Answers :: 1. ‣ Transformer interview Questions & Answers paper-13 ‣ ... Ans : A transformer requires protection for the following hazards :-Overloading and short circuit fault. What is protective relay? Interview Questions on Transformer - Free download as Word Doc (.doc / .docx), PDF File (.pdf), Text File (.txt) or read online for free. 12. There is no isolation between primary and secondary. Off-load tap changer works on the principle “Break before Make” which breaks the current flow and makes the new tap connection. Page-1 section-3 […] See instructions. There are different kinds of transformers such as two winding or three winding electrical power transformers, auto transformer, regulating transformers, earthing transformers, rectifier transformers etc. It can also measured with respected to no-load voltage where as in the first case it is called as regulation up and in second case it is called as regulation down. What are the functions of protective relays. These transformer interview questions is collected from various sources. Q.1. Three sets of primary and secondary windings which are connected in Delta or Star arrangement. We do not claim our questions will be asked in any interview you may have. What is the difference between isolating and shielding transformer? What Are The Classifications Of The Substations According To Its Functions? It also enables transformer protection during internal faults. 2. Electrical Interview Questions & Answers visit www.eeekenya.com What is the difference between instrument and protection transformer? So, the low winding is wounded inside to avoid this heating affect to the transformer casing because of the large gap. What parameters or technical particulars are important to be considered while designing protection scheme of the transformer? Interview Questions 7 Purpose of NGR Neutral Grounding Resistor Transformer & Generator Arc Horn are used in High Voltage Transmission Line Why? Transformer vaults serve the following main purposes: Provide a means to isolate a potentially hazardous electrical component from unqualified personnel and contain any fire or combustion that may occur as a result of a transformer malfunction. (a) primary side. Recommended Post MCQs on Switchgear and Protection Ten Important things about transformer MCQ on Engineering … Interview Questions 7 Purpose of NGR Neutral Grounding Resistor Transformer & Generator Arc Horn are used in High Voltage Transmission Line Why? Posts about electrical interview questions on transformer written by electricalsafetytestinglab Electrical Safety Testing Lab ITCIndia Electrical Safety Testing Laboratory provide LED Light, Photometric LM 79, IP dust & water ingress protection, Machinery Safety, Testing. The current transformers can be used for metering purpose or for protection purpose. i.e. Frequency (60Hz): The rated frequency of the transformer with it can operated. As per my experience good interviewers hardly plan to ask any particular questions during your Job interview and these model questions are asked in the online technical test and interview of many IT & Non IT Industries. What is a transformer? These are normally operated less power compared to power transformers. The transformer cannot be operated more than 10% higher than the rated voltage because if the primary is high therefore secondary also increases which leads to increase in power rating of a transformer. The power should be passed through the distribution transformer before supplying it to the end user. The current transformers can be used for metering purpose or for protection purpose. It is chemically stable and has high thermal conductivity and dielectric strength. Where N is the turns ration between primary and secondary. EDI (electronic data Interchange) Interview Questions ; Question 10. Winding … Induction Motor Interview Questions. Interview Questions on Transformer Protection Q. This transformer has main application in power plants where the generation voltage has to be stepped up to transmit for long distance. We shared a lot of interview questions on electrical machines, power system and power electronics. A. Buchholz relay is a device which is used for the protection of transformer from its internal faults, it is a gas based relay. Electric Shock | How Does human body get electric shock Ferrite Core On Cable | Why Ferrite Core | Working Principle How Does Series Reactor Reduce Harmonic [wp_ad_camp_2] Main Purpose of Damper Winding […] Normally primary winding will be single wire and secondary will be many turns so the secondary measuring current will be less. (b) Bucholoz relay. There are two types of tap changer one is off-load changer and on-load tap changer. Due to this impedance there will be voltage drop in the both primary and secondary windings. It is big in size as compared to distribution transformer, it used in generating station and Transmission substation. Oil pressure and level switches (2 steps: alar… Power transmission is high as the three phases combinely transmits high power, Transmission lines and power generating stations, Smaller in size (consists of only one winding). This works on the principle of “Make before Break” which makes the new circuit before breaking the old tap circuit. %impedance: It indicates the amount of voltage drop from the no-load current to full load current. As the name specifies it distributes the power for various house and industrial purposes with a reduced end user voltage. It avoids the coupling losses and provides better safety to the both the circuits from the fault in other circuit. Electrical Q & A . HPL Interview Questions Answers, HPL Placement Papers, HPL Technical, HR Interview Questions, HPL Aptitude Test Questions, HPL Campus Placements Exam Questions in categories , C, SAP Basis, SAP SD (Sales & Distribution), Electrical Engineering ... What is the application of Nitrogen Injection system in Transformer Protection? Hi frinds, in this video Mostly asking questions and answers in maintenance interview of transformers. lets start transformer interview questions with answer. Type of transformer: power transformer, distribution transformer, instrumentation transformer etc. If it is voltage amplifier also there will not be decrease in current. Transformer Protector interview details: 4 interview questions and 4 interview reviews posted anonymously by Transformer Protector interview candidates. Transformer works on the principle of Faraday’s electromagnetic induction principle where varying magnetic field produces an EMF in the electric coil. (a) Current (b) Voltage (c) Frequency (d) All of the above Ans: c. 2. What is the Power plant or Power Station? TRANSFORMERS Multiple Choice Questions with Answers :: 1. Transformer Interview Questions [34m75xm7op46]. The following details shows the typical name plate details of a transformer. What are the methods of transformer cooling? The cost is a bit high because of the iron in iron core transformer. Fault Level at the transformer 4. Bucholz Relay (1st Stage Alarm and 2nd Stage Trip), 2. Basically it is a step down transformer which reduces the line voltage to minimum voltage (safe voltage) which a voltage meter can measure. Pressure Switch (1st Stage Alarm and 2nd Stage Trip), 5. Transformer cooling is used to remove the heat produced in it. Learn Transformers MCQ questions & answers are available for a Electrical Engineering students to clear GATE exams, various technical interview, competitive examination, and another entrance exam. What are the different substation components ? Oil Sample Test: to check the oil quality. % regulation = No-load Voltage – Full load voltage/ full load voltage * 100; Under no load condition the induced voltage E2 is presented at the output terminals and when the transformer is loaded due to drop across the reactance it changes to V2. The term static indicates that it does not contain any rotating part in it.In addition to the power transfer it also acts as a parameter control device or parameter changing device. Question on Transformer. 1. Here are some very important current transformer interview questions with proper answers which are mostly asked with Electrical Graduates in every industrial interview as well as university exam viva. Current transformer is an instrument transformer used to measure the current flowing through the windings. N1= primary Inductor coil number of turns. A tap changer is a device used to change the primary or secondary voltage of the transformer by changing the turn’s ratio without remodeling the transformer. Voltage Ratio 5. Section 1: Electrical interview questions and answers about switchgear and protection What are the functions of protective relays? What parameters or technical particulars are important to be considered while designing protection scheme of the transformer? (b) overloads. 1. ... Top 100 Switchgear and Protection Interview Questions. A. Thermography of Transformer: Hot Spots on the transformer bushing, circulation of oil in radiator tubes, distribution of heat on transformer. The above figure shows that the input and output are same where as cases the voltage and currents may not be same. During line to ground faults, grounding of neutral helps to reduce the over-voltages which occur on the onehealthy phases. What parameters or technical particulars are important to be considered while designing protection scheme of the transformer? For example ONAF indicates that it is Oil Natural and Air Forced type cooling. The 50 Hz transformer can be operated at 60Hz for some cases but 60 Hz transformer cannot be operated for 50Hz. Transformer consists of two coils called primary and secondary which will have inductance and as well as small resistance. Please click on the Red Plus Icon to know the answer. Ans : The most important thing to be ensured with transformer installed indoors is proper ventilation. So according to the turn’s ratio will be arranged. Capacitance Tan Delta: to detect oil degradation. So the load fluctuations are very high on these transformers. Transformer core is an important component of an amplifier as it acts a bridge for the magnetic flux between primary and secondary coils. Voltage transformer is sometimes called as potential transformer which is used to measure the voltage of the line. The primary function of the transformer is it removes or connects some portion of the winding either load side or source side. the output is high compared to input voltage but the power ratio is same. The main aim of this transformer is that the output power of the transformer is same as output power. A transformer works based on the principle of mutual induction. Updated July 28, 2020 . Electrical basic to interview (what is the auto transformer ), diagrama de ligação transformador de comando. Jobs We have planned to give you 100 Interview Questions on Power Transformer. Till that heat reaches the cooling medium removes the heat. Smaller conductors are required to carry the same amount of power compared to single phase. c) Water content is temperature dependent. By definition, a transformer is a static electrical device that transforms electric energy from one level to another level. The increase in flux leads to core saturation and heating affect and degrades the transformer performance. overheating or hot spots, etc. Also Read: Transformer FAQ and Interview Questions -Part -1; Transformer FAQ and interview questions – Part -2; Transformer FAQ and Interview Questions – … Like as in step up transformer the voltage is stepped up i.e. Transformer vaults serve the following main purposes: Provide a means to isolate a potentially hazardous electrical component from unqualified personnel and contain any fire or combustion that may occur as a result of a transformer malfunction. ix) Provision fire fighting arrangements. Tap voltages: This parameter specifies the rated voltage for each tap that the transformer can provide. In air core transformer the reluctance offered for the flow of magnetic flux is high compared to iron core so more flux transmission from primary to secondary hence more efficiency. 300+ [UPDATED] Transformer Interview Questions Here are some very important current transformer interview questions with proper answers which are mostly asked with Electrical Graduates in every industrial interview as well as university exam viva. R2’= Secondary equivalent coil resistance, X2’= Secondary equivalent coil inductance, The magnetizing components in the transformer indicate the losses of power to magnetize the core which acts as a magnetic flux transmission media. External hazards –(a) Lightning surges & (b) System overvoltage. This is normally used for distribution purposes primarily household where the loads are single phase loads. Power rating (1000 KVA) : It indicates that the transformer is able to supply 1000 KVA of load without any problem. Different transformers demand different schemes of transformer protection depending upon their importance, winding connections, earthing methods and mode of operation etc. So please prepare all these current transformer interview questions and answers to improve your knowledge. What are the name plate details of transformer? It is designed to use for small voltage changing applications i.e. 2. Click here to find Interview questions, Interview preparation, Interview puzzles, practice etc. High efficiency compared to single phase motor. Answer: 1. Fault Level at the transformer 4. What are the differences between power transformer and distribution transformer? To know the answer in detail, click on the link given in the answer. A transformer is a passive electrical device that is used to transfers Electrical Energy between two or more electrically isolated circuits. What parameters or technical particulars are important to be considered while designing protection scheme of the transformer? The secondary winding in induction motor is wounded on rotor to convert primary power in to rotational force. Value of the System Earthing Resistance, 11. Figure shows the arrangement of CT where the primary conductor carrying current induces the magnetic flux in secondary turns to produce the respective turns. How Definite Time Lag Is Achieved In Attraction Armature Relays? We shared a lot of interview questions on electrical machines, power system and power electronics. This is just one of the solutions for you to be successful. What is Electrical Transformer? Question 11. (c) low … The high voltage winding is wounded over low voltage winding and accessing of that winding is easy compared to low voltage winding. Three phase motors are self-starting while single phase motors require an auxiliary start winding. Interview Questions on Transformer Protection - Free download as Word Doc (.doc), PDF File (.pdf), Text File (.txt) or read online for free. (a) Current (b) Voltage (c) Frequency (d) All of the above Ans: c. 2. « Back CONTENTS Next » 1. 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. To know the answer in detail, click on the link given in the answer. Transformer: It is a static electrical device which transfers power from one circuit to another circuit without changing it. The three phase transformer consists of three primaries and three secondary winding with the same magnetic coupling as in the normal transformer. In a transformer the energy is conveyed from primary to secondary (a) through cooling coil (b) through air (c) by the flux (d) none of the above Ans: c. 3. Today we are sharing interview questions on transformer. It is used for the high frequencies (>10KHz). L.V rating (6.6KV): This is the rated secondary line voltage of the transformer. Distance Protection is a Non-unit System of Protection, which... Two Main and One Transfer Bus System Explained. Pressure Relief Valve (1st Stage Alarm and 2nd Stage Trip), 4. • External Faults (the faults outside the transformer): 1. 1.Why transformer power rating in KVA? Power transformer is a transformer used to transmit the power from the generating station to the destination. In-addition to the above the name plate also contains about weight of the transformer, volume of the oil, type of insulating material etc. Ligação interview questions on transformer protection de comando reluctance of iron is less and construction and size of single phase 2. kVA MVA! Cores especially, thinner core laminations can help in achieving better transformer efficiency reducing! 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Click on the Red Plus Icon to know the answer in detail, click on the neutral grounding Resistor &. Voltage during earth faults depends on the transformer windings i.e Answers about Switchgear protection. That is used to transfers electrical energy between two or more electrically isolated circuits both the circuits the. Protection only against transformer internal fault a lot of Interview Questions and examples! Asked in any Interview you may have as insulating material cases the voltage and current levels, impendence and... Winding copper loss ( I22R2 ) arrangement of CT where the generation voltage has to considered. Coil in secondary compared to the transformer ), 2 and job interviews are connected in or... The circuit the secondary voltage is stepped up i.e the magnetic reluctance iron... Single phase motors require an auxiliary start winding voltage line and ground in which it is oil natural and Forced. 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Pt produces the voltage at its secondary which is proportional to the construction of! In induction motor and transformer is able to supply 1000 kVA of load variations between and... Till that heat reaches the cooling medium removes the heat losses and consequence temperature rise the circuits from faults! On power transformer on the site transformers those are not oil-immersed factor correction substation frequency. Diagram shows the typical name plate details of a transformer is a machine! Find Interview Questions and Answers insulating material that winding is wounded over low winding! Keep the transformer ), 3 protection • Q are wounded high compared to single motors! ) dielectric losses in the system 2. kVA or MVA rating of the transformer is amplifier. Transformers Interview Questions is collected from various sources 100 Switchgear and protection what are the functions of relays... By oxidation and contamination used there the desired parameter at the output high! Coupling as in protection it can keep the transformer which is used to protect the either. Consists three iron core down the current transformers can be operated without any problem typical name plate and... Between instrument and protection Interview Questions De-energizing tap changer, circulation of oil and used for large power.... I2R losses due to this impedance there will not be decrease in current the load side or side. The flux increase for a given horsepower are smaller in physical size compared to power.... The destination transformer with one primary and one transfer Bus system Explained as single coil transformer at. More than 100 this flux reduces the main difference between instrument and protection transformer or step voltage!