Electrical Engineering Questions

Question: What is breaking capacity of circuit breakers and how it is expressed? Answer: The breaking capacity of circuit breakers is rated RMS current that a circuit breaker is capable of breaking at rated recovery voltage. Explanation The breaking capacity of CB is rated current at which a CB is capable of breaking the circuit at … Read more

Question: Give the analytical reason for justifying the use of rated voltage in MVA breaking capacity ratings of the circuit breaker? Answer: The MVA breaking capacity of the circuit breaker is the product of short-circuit current (A) and normal rated service voltage. At a glance, one might think the use of rated voltage rating is … Read more

Question: Why overload protection is not employed/used with alternators? Answer: Overload protection is not important for alternators because overloading seldom occurs on power plants. Explanation: The chances of overloading faults on alternators are negligible. The actual power generation depends on prime mover which is continuously observed and regulated by governors and regulators. Furthermore, such protection … Read more

Question: What does abbreviation ACSR stand for in transmission lines? Answer: ACSR stands for aluminum conductor steel reinforced and it is one of most commonly employed composite conductor for overhead transmission lines. Aluminum is a good conductor of electricity. Its good conduction properties make it very popular to be used in transmission lines. However, its … Read more

Question: Why Buchholz relay should only be used with oil immersed transformers? Answer: The actuation of Buchholz relay relies on the gas generated from transformer oil due to which it should be used only with oil immersed transformers. Working of Relay The Relay is installed in the pipe joining conservator tank to the main body … Read more

Question: Why isolator is known as offload device? Answer: Isolator is a knife switch responsible for isolating a portion of the circuit from the power system. It should be opened after switching off the connected breakers, or else the current will generate heavy arcs spanning over meters. Other questions: Why liquid fuels are preferred over … Read more

Question: How many types of faults exist on the power system and how they are classified? Answer: Generally four types of faults exist and are classified into two categories. Symmetrical faults: They give rise to symmetrical equal currents having a displacement of 120°. Unsymmetrical faults: They gave rise to unsymmetrical currents having unequal displacements. List … Read more

Question: Explain the basic difference between base load and peak load power plants? Answer: Base load power plant powers the continuous electrical load which occurs throughout the day. A peak load power plant runs to meet the electrical demand during the peak hours. Difference between Base load and Peak Baseload is the normal load which … Read more

Question: Why surge tank is built (installed) with close conduit hydroelectric power plants? Answer: Closed conduit of dam faces the irregular pressure of water under varying loads. A surge tank is installed for relieving the conduit pipes under varying loads. Explanation In hydroelectrical power plants, water conduits connect the link to the turbine housing. During … Read more

Question: Name the unique feature of the nuclear power plant which distinguishes it from conventional plants? Answer: The unique feature of the plant is enormous power capability of nuclear fuel. Very small amount of nuclear fuel can generate an enormous quantity of electricity. It is estimated that 1 kg of uranium can produce energy as … Read more