VISH WIND INFRASTRUCTURE Interview Questions and Answers

Reactive power loss in transformer can be calculated using the formula Q = V^2/X, where V is the voltage and X is the reactance.

• Reactive power loss occurs due to the magnetic field in the transformer

• It is important to calculate reactive power loss to ensure efficient operation of the transformer

• Reactance can be calculated using the formula X = 2πfL, where f is the frequency and L is the inductance

• Reactive power loss ca...read more

Over current protection is for excessive current flow, while earth fault protection is for current leakage to earth.

• Over current protection is used to protect against excessive current flow in a circuit.

• Earth fault protection is used to detect current leakage to earth.

• Over current protection is typically achieved using fuses or circuit breakers.

• Earth fault protection is typically achieved using residual current devices...read more

Single phase loading of three phase transformer

• Single phase loads can be connected to one or two phases of a three phase transformer

• The third phase remains idle and no current flows through it

• The transformer's capacity is reduced when single phase loads are connected

• The transformer's efficiency may also be affected

• Examples include residential and small commercial buildings with single phase loads

Duty cycle of SF6 circuit breaker refers to the ratio of time it can be operated to the total time period.

• Duty cycle is expressed as a percentage

• It is important to ensure that the breaker is not operated beyond its duty cycle

• For example, if the duty cycle is 50%, the breaker can be operated for 30 minutes in an hour

• Exceeding the duty cycle can cause damage to the breaker and reduce its lifespan

Explanation of fast bus transfer logic and 2/3 logic in bus system. Logic diagrams for auto reclosing in switch yard.

• Fast bus transfer logic is used to quickly transfer power from one bus to another in case of a fault or maintenance.

• 2/3 logic in bus system refers to the use of two out of three sources to power a bus, ensuring redundancy and reliability.

• Auto reclosing in switch yard is a mechanism to automatically resto...read more