Virtual Labs

Development of 11KV/433 volts substation automation using PLC for normal load operation

The main function of substations are

a: To receive energy transmitted at high voltage from the generating stations Explanation

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b: To decrease the voltage to a value appropriate for local distribution Explanation

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c: To provide switching facilities Explanation

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d: All Explanation

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Substations generally have

a: Switching and protection equipment Explanation

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b: Transformers Explanation

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c: Control equipment Explanation

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d: All Explanation

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A circuit breaker is an automatically operated electrical switch designed to protect an electrical circuit from damage caused by ________.

a: Overhead Explanation

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b: Short circuit Explanation

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c: Both overhead and short circuit Explanation

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d: None Explanation

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The important characteristics of the fluid used in Circuit Breaker are :-

a: It should have good thermal and chemical stability Explanation

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b: It should have high dielectric strength and are extinguishing ability Explanation

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c: Non- inflammability and high thermal conductivity Explanation

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d: All Explanation

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The advantage of using oil in Oil Circuit Breaker as an arc quenching medium is:

a: It has high dielectric strength Explanation

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b: As a result of decomposition of oil, it has good cooling property Explanation

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c: Both it has high dielectric strength and as a result of decomposition of oil, it has good cooling property Explanation

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d: Highly inflammable Explanation

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SF6 circuit breaker is ________

a: Expensive Explanation

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b: SF6 gas has to be reconditioned after every operation of the breaker and additional equipment is required for these purposes Explanation

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c: Both expensive and SF6 gas has to be reconditioned after every operation of the breaker and additional equipment is required for these purposes Explanation

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d: None Explanation

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Instrument Transformer are used because

a: It is cheap Explanation

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b: It provides more safety Explanation

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c: It is not practicable to connect instruments and meters directly to the lines in high voltage circuits Explanation

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d: Both It provides more safety and It is not practicable to connect instruments and meters directly to the lines in high voltage circuits Explanation

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A potential transformer is a

a: Step up transformer Explanation

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b: Step down transformer Explanation

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c: Both step up transformer and step down transformer Explanation

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d: None Explanation

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A current transformer is a

a: Step up transformer Explanation

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b: Step down transformer Explanation

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c: Both step up transformer and step down transformer Explanation

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d: None Explanation

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Big porcelain bushing, hollow insulators can be used up to _______ kV.

a: 200 kV Explanation

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b: 400 kV Explanation

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c: 1000 kV Explanation

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d: 3000 kV Explanation

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The use of ________ for high voltage applications is becoming more common.

a: Oil Explanation

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b: Porcelain Explanation

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c: Polymer Explanation

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d: All Explanation

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The transformer works on principle of ___________

a: Self-induction Explanation

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b: Mutual induction Explanation

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c: Both self-induction and mutual induction Explanation

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d: None Explanation

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DC supply __________ be used for the transformer.

a: Can Explanation

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b: Connect Explanation

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c: Both Can and Connect Explanation

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d: None Explanation

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The ratio of secondary induced emf to primary induced emf is known as ___________

a: Voltage transform ratio Explanation

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b: Current ratio Explanation

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c: Power ratio Explanation

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d: All Explanation

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Current ratios are in _________ of the voltage ratio.

a: Direct ratio Explanation

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b: Inverse ratio Explanation

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c: Power ratio Explanation

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d: None Explanation

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The transmission voltage in India are __________ .

a: 400 kV Explanation

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b: 220 kV Explanation

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c: 132 kV Explanation

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d: All Explanation

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Transmission network is commonly known as ____________

a: Pan Explanation

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b: Lock-head Explanation

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c: Grid Explanation

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d: All Explanation

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_________ is one of the best conductors due to its high electrical conductivity and high tensile strength for all type of transmission.

a: Phosphor brown materials Explanation

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b: Galvanised iron Explanation

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c: Aluminium Explanation

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d: Copper Explanation

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Aluminium has _______ the resistivity of copper.

a: 12 times Explanation

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b: 24 times Explanation

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c: 3 times Explanation

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d: 16 times Explanation

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When 1 or 2 percentage of cadmium is added to copper it __________ the tensile strength by ________ but ________ the conductivity by ________.

a: Decreases, 40% , Increases, 20% Explanation

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b: Decreases, 20% , Increases, 40% Explanation

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c: Increases, 40% , decreases, 17% Explanation

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d: Increases, 17% , decreases, 40% Explanation

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The advantage of using suspension type insulators over pin-type insulators is _________

a: Cheaper in cost for operating voltage above 50kV Explanation

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b: Flexibility is increased with suspension insulators Explanation

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c: If line insulation needs to be increased, the additional insulators can be easily added to the string Explanation

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d: All Explanation

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Reason for failure of insulator is

a: Mechanical stress Explanation

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b: Short circuits Explanation

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c: Flash-over Explanation

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d: All Explanation

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In double bus bar system ,there is a provision of a bus-bar coupling switch for transferring operation from one bus-bar to another _________

a: True Explanation

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b: False Explanation

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Lighting arrestor are installed in

a: Power poles and towers Explanation

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b: Power transformer and circuit breakers Explanation

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c: Bus structures and steel superstructures in substation Explanation

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d: Any of them Explanation

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