Larsen & Toubro Group Senior Electrical Engineer Interview Questions and Answers

HVDC is a technology used to transmit high voltage DC power over long distances. Offshore connections refer to power transmission from offshore wind farms.

• HVDC is more efficient than AC transmission over long distances

• Offshore connections require specialized equipment and installation techniques

• HVDC is used for offshore connections to transmit power from offshore wind farms to the mainland

• Examples of HVDC projects incl...read more

Construction building in raising panel installation involves proper planning, coordination, and adherence to safety regulations.

• Ensure all necessary materials and equipment are available before starting the installation process

• Coordinate with other trades to ensure smooth workflow and avoid conflicts

• Follow safety regulations and guidelines to prevent accidents and injuries

• Properly train and supervise workers to ensure ...read more

DOL starter stands for Direct-On-Line starter, used to start motors by directly connecting them to the power supply.

• DOL starter is the simplest and most common type of motor starter.

• It directly connects the motor to the power supply without any intermediate starting method.

• It provides full voltage to the motor during starting, which can cause high inrush current.

• DOL starters are suitable for small to medium-sized motor...read more

APFC PANEL stands for Automatic Power Factor Correction Panel, used to maintain power factor in electrical systems.

• APFC PANEL automatically monitors and corrects the power factor of electrical systems.

• It helps in reducing electricity bills by maintaining a high power factor.

• APFC PANELs are commonly used in industries and commercial buildings.

• They consist of capacitors that are switched on and off based on the load requ...read more

CB is a switch that can interrupt the circuit during fault conditions, while an isolator is a switch that can only isolate the circuit.

• CB is used for protection against overcurrent, short circuit, and earth fault

• Isolator is used for isolation of a circuit for maintenance or repair work

• CB can be operated manually or automatically, while isolator is operated manually only

• CB has contacts that can break the circuit, while

The rating of equipment in a substation is crucial for its efficient functioning.

• The rating of transformers should be based on the maximum load they are expected to carry.

• Circuit breakers should be rated for the maximum fault current they may encounter.

• Busbars should be rated for the maximum current they may carry.

• Lightning arresters should be rated for the maximum voltage they may encounter.

• The rating of capacitors sh...read more

A power transformer is an electrical device that transfers electrical energy between two or more circuits through electromagnetic induction.

• It is used to step up or step down the voltage of an alternating current (AC) power supply.

• It consists of two or more coils of insulated wire wound around a magnetic core.

• The primary coil is connected to the input voltage source and the secondary coil is connected to the output loa...read more

Different types of tests to be performed in power transformer

• Insulation resistance test

• Ratio test

• Polarity test

• Vector group test

• No-load test

• Load test

• Temperature rise test

Relays are used to control high voltage or current circuits with low voltage signals.

• Electromagnetic relays use an electromagnet to open or close a circuit.

• Solid-state relays use semiconductors to switch the circuit.

• Thermal relays protect motors from overheating by tripping the circuit when the temperature exceeds a set limit.

• Time delay relays are used to delay the opening or closing of a circuit for a specific time pe...read more