SF6 Circuit Breaker Question & Answers April 4, 2023 By Wat Electrical This article lists 75 SF6 Circuit Breaker MCQs for engineering students. All the SF6 Circuit Breaker Questions & Answers given below include a hint and a link wherever possible to the relevant topic. This is helpful for users who are preparing for their exams, interviews, or professionals who would like to brush up on the fundamentals of SF6 Circuit Breaker. An SF6-based circuit breaker is a type of circuit breaker that uses SF6 – Sulphur hexafluoride in gas form as its substance for arc quenching. It is the most electronegative substance. The range of the SF6 circuit breaker in voltage is 144 to 765 kV or above. The components of double-pressure type SF6 circuit breakers are fixed contact, movable contact, fixed cylinder, and compressed SF6 gas. The designs of the SF6 circuit breaker includes live, dead, and grounded tank-based circuit breaker. The property of SF6 gas includes good insulating properties, greater affinity, and greater electronegativity. The advantages of SF6 based circuit breaker include less arching time, compact in design, and noiseless-based operation. The disadvantages of the SF6 circuit include; it is heavier in volume, costly, and requires constant monitoring. The applications of SF6 CB include transformer protection, rectifier, and capacitor circuits. 1).What is the abbreviation of SF6 in SF6 type circuit breaker? Sulfur hexafluorate Sulfur hexafluoride Sulfuric hexafluoride Sulfur fluoride Hint 2). What is the use of SF6 circuit breaker? High power Low vacuum Arc extinguisher All the above Hint 3). Which type of gas is SF6 circuit breaker? Electro-positive gas Electronegative gas Nitrogen gas Neon gas Hint 4). What is range of SF6 circuit breaker in voltage? 110 to 500 kV 100 to 650 kV 150 to 800 kV 144 to 765 kV Hint 5). What are the main parts of SF6 circuit breaker? Interrupt unit Gas system Inverted a and b Hint 6). How many types if SF6 circuit breakers are there? 2 3 4 5 Hint 7). What are the components of double pressure type SF6 circuit breaker? Fixed contact Movable contact Compressed SF6 gas All the above Hint 8). What is the voltage range of single pressure type SF6 circuit breaker? 10kV to 450kV 12kV to 650kV 13.6kV to 760kV 15kV to 800kV Hint 9). Which is the property of SF6 gas in its pure state? Black color Non-toxic Bad smell All the above Hint 10). What is the density of SF6 gas? 4 g/l 5.5 g/l 6.16 g/l 7 g/l Hint 11). SF6 is used as _____ medium in a SF6 circuit breaker? Arc quinching Arc edit Arc moment Arc dilute Hint 12). Which of the following is the property of SF6 gas? Good insulating property Greater electronegativity Greater affinity All the above Hint 13). Which of the following is the chemical equation of SF6? SF6 + e = SF6 - SF6 + e = SF-5 + F SF6 - e = SF-5 + F Both a and b Hint 14). _____ are of much mass compared to electrons in a SF6 circuit breaker? Protons Ions Neutrons Both a and b Hint 15). SF6 requires _____ value in higher quantity when charge particles are less and heavier? Dielectric Electric Conductive Capacitive Hint 16). ____ property of SF6 based circuit breaker heat is transferred efficiently? Low viscosity High viscosity Low friction High friction Hint 17). SF6 based gas has ___number effective compared to quenching media? 100 time 200 times 300 times 400 times Hint 18). ____ voltage levels are covered in SF6 circuit type breaker for a power system? Medium High Low Both a and b Hint 19). Which of the following are the disadvantages of circuit breaker? Green house based gas Requires greater mechanical energy High input voltage Both a and b Hint 20). Which of the following is the voltage level of 2 interrupter based SF6 CB? 220kV 400kV 800 kV 1000 kV Hint SF6 Circuit Breaker Questions for Interviews 21). Which of the following is the voltage level of 4 interrupter based SF6 CB? 220kV 400kV 800 kV 1000 kV Hint 22). To which of the following type of CB does SF6 based CB is similar to? Air blast CB Water blast CB Chemical CB Both b and c Hint 23). A SF6 gas in SF6 CB is _______ in a high pressure based reservoir? Compressed Stored Evaporated Both a and b Hint 24). Which of the following are the types of air based circuit breaker? Plain Air Water Both a and b Hint 25). Which of the following are the advantages of air based CB? Zero fire hazard high breaking speed Quenching of arc is faster All the above Hint 26). Which of the following are the disadvantages of air based CB? High compressor maintenance Zero air pressure leakage Re-striking increase All the above Hint 27). Arc quenching process is also called? Arc interruption Arc Extinction Arc Transfer Both a and b Hint 28). Which of the following are the components of interrupter unit of a SF6 CB? Fixed contacts Moving contacts Chamber All the above Hint 29). _____ type of contact in a SF6 based CB has hollow based cylinder contact? Fixed Dynamic Static Both a and c Hint 30). When ambient based temperature is fallen below 16 degrees then the ____ device connected is shorted? Thermostat Resistor Capacitor Load Hint 31). Occurrence of fault in circuit breaker __ the contacts? Isolates Separates Contacts Both a and b Hint 32). ____ is the pressure value of interrupting chamber of SF6 based arc? 16kg/cm^2 26kg/cm^2 36kg/cm^2 6kg/cm^2 Hint 33). SF6 based gas attracts ______ in an arc lane? Free electrons Protons Neutrons Both a and b Hint 34). When arc of SF6 based CB is extinguished then force of present gas_____? Increased Decreased Constant Zero Hint 35). ____ is the pressure value of gas in a SF6 based CB? 3kg/cm 2 5kg/cm2 6kg/cm2 7kg/cm2 Hint 36). Which of the following is old circuit breaker? SF6 Vacuum Air blast Both a and c Hint 37). The arc in SF6 based CB is? High Low Constant Zero Hint 38). Which of the following is the short circuit condition observed in a SF6 based circuit breaker? 10 to 50 30 to 100 20 to 30 30 to 60 Hint 39). ____ property is high in SF6 based circuit breaker? Reliability Dielectric Cost All the above Hint 40). Which of the following are the types of SF6 based circuit breakers? Non-puffer Single pressure Double pressure All the above Hint SF6 Circuit Breaker MCQs for Students 41). _____ type of SF6 CB operation principle is similar to air blast based CB? Non-puffer Single pressure Double pressure All the above Hint 42). In a single pressure based puffed CB ___ component acts as bridge between stable based contacts? Cylinder Shaft Arc All the above Hint 43). The pressure in double SF6 based circuit breaker is released via ___ flow? High to low Low to high Low to medium medium to high Hint 44). Which of the following are units of pressure? Pascal Newton Farads Meters Hint 45). Which of the following are the advantages of SF6 based circuit breaker? Less arching time Compact in design Noiseless based operation All the above Hint 46). Which of the following are the disadvantages of SF6 circuit? Heavier in volume Costly Requires constant monitoring All the above Hint 47). Which of the following are the applications of SF6 CB? Transformer protection Rectifiers Capacitor All the above Hint 48). What is reason for used of SF6 CB? Non-flammable Electrical insulation is high No toxicity All the above Hint 49). Which is the reason for SF6 not being flammable? High chemical stability Low chemical stability High resistance Low power Hint 50). Which of the following is the voltage level of Vacuum CB? 12kV 72kV 40kV 50kV Hint 51). Which of the following is pressure value of SF6 CB? 2.8kg/cm2 3kg/cm2 4kg/cm2 5kg/cm2 Hint 52). SF6 gas ____ the arc of opening a circuit? Cool Quench Break Both a and b Hint 53). In which SF6 CB are incorporated? Gas insulated switched gear Gas isolated Switched gear All the above Hint 54). Which of the following is the symbol used for electro negativity? C X Z R Hint 55). Which of the following factors are used for determining electronegative factor? Nuclear charge Electron location Proton location Both a and b Hint 56). Which of the following is the maximum voltage value of high voltage based CB? 200kV 2000kV 800kV 8000kV Hint 57). ____ mechanism is used for driving high voltage circuit breaker of 800kV? Low energy spring loaded mechanism High energy spring loaded mechanism Low energy de-loaded mechanism Medium energy spring loaded mechanism Hint 58). Circuit based breakers are classified based on____ substances? Air Oil Vacuum All the above Hint 59). A circuit breaker is a ___ type of safety device? Electrical Mechanical Electronic Chemical Hint 60). How many symbols does a circuit breaker is represented as? 2 3 4 5 Hint 61). Which of the following is the purpose of a circuit breaker? Removes power from faulty function Removes the component Open circuit All the above Hint 62). Abbreviated OCPD? Over Current Protection Device Over Cut Protection Device Open Current Protection Device Over Cut Potential Device Hint 63). A fuse is a ___ type of device? Active Passive Source independent Both a and b Hint Read more about Electrical Fuse 64). Which of the following are the components of fuse? Metal strip Silica sand Air All the above Hint 65). The strength of arc in CB depends on ? Voltage Pressure Temperature All the above Hint 66). The mobility of charge in a DF6 CB is ______? High Low Constant Medium Hint 67). Which of the following are the chemical properties of a circuit breaker? Stable Non-toxic Non-corrosive All the above Hint 68). Which of the following are the electrical properties of circuit breaker? Greater dielectric strength Arc quenching Zero effect of voltage on dielectric strength All the above Hint 69). A interrupter in CB comprises of? Current carrying based conductors Vent Arc All the above Hint 70). SF6 gas form is ______ in a tank? Cooled Compressed Stored Both b and c Hint 71). Which of the following are the reason for less maintenance of CB? Closed circuit gas system Zero carbon decomposition Zero moisture settlement All the above Hint 72). Up to which voltage does SF6 handles? 800kV 900 kV 1000kV 1200kV Hint 73). Which is the voltage level of single pressure based SF6 CB? 13.6kV – 760kV 14kv- 800kV 15kv – 900kV 20kv to 1000kv Hint 74). Which of the following are the designs of SF6 circuit breaker? Live tank Dead tank Grounded tank All the above Hint 75). SF6 in its pure form is ____? Odorless Colorless Tasteless All the above Hint For More MCQs Circuit Breaker Question and Answers. Time's up
