25 Top Power Plant Electrical Interview Questions

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Power Plant Electrical Interview Questions

Energy sources fall into two categories:

  • Non-conventional primary sources, such as geothermal energy, solar energy, ocean tides & waves, wind, and so on.
  • Conventional secondary sources include fossil fuels such as coal, oil, and natural gas, as well as hydraulic and nuclear energy.
  • Thermal power station
  • Hydroelectric power station
  • Diesel power station
  • Nuclear power station
  • Gas-turbine power station
  • Magnetohydrodynamic power station.

A thermal power plant burns fuel (which include coal or gas) to generate heat, which is then converted into steam. The steam propels a turbine, which in turn powers a generator to generate electricity.

  • Coal & ash circuit
  • Air & flue gas circuit
  • Feed water & steam circuit
  • Cooling water circuit.

The equipment that drives the electric generator or provides mechanical power to the generator is known as a prime mover.

The air and flue gas circuit includes 

  • Forced draught fan, 
  • Air pre-heater, 
  • Boiler, 
  • Furnace, 
  • Super heater, 
  • Economizer, 
  • Dust collector, 
  • Induced draught fan, and 
  • Chimney.

The feed water & steam flow circuit consists of a 

  • Feed pump, 
  • Economizer 
  • Boiler drum super heater, 
  • Turbine, and 
  • Condenser.
  • Uranium, 
  • Plutonium, and 
  • Thorium 

are among the most regularly utilized fuels. 

It could be U-235, U-238, Pu-236, or Th-232. 

Uranium is widely selected due to its high melting point.

Solar panels in a grid-connected solar power system convert sunlight into direct current (DC) electricity. Inverters convert the DC electricity into AC power, which is then delivered into the electrical grid. The electricity generated may be utilized directly by the consumer (or) fed into the grid.

Load dispatching is the process of optimizing and controlling power generation & transmission to fulfill electricity demand. It comprises assessments on unit commitment, economic dispatch, & load frequency control.

Supercritical power plants run at higher pressures & temperatures, resulting in greater efficiency than subcritical power plants. They use improved steam characteristics to maximize thermal efficiency.

  • Heat rate, 
  • Efficiency, 
  • Availability, 
  • Capacity factor, and 
  • Pollution levels 

are key performance indicators for power plants.

A hydroelectric power plant uses the potential energy of water contained in a dam. The water flows through turbines, which turn generators to generate power.

Advantages: Coal’s abundance & low cost make it a desirable fuel source. 

Disadvantages: Limitations include environmental pollution, emissions, & the requirement for improved emission control systems.

A synchronized generator is one that runs in parallel with other generators in a power system. It is essential for ensuring grid stability, load sharing, & a consistent power supply.

A solar PV system includes 

  • Solar panels, 
  • Inverters, 
  • Mounting structure, 
  • Electrical wiring, & 
  • Monitoring system.

A gas turbine power plant compresses air, mixes it with fuel, and burns it in a combustion chamber. The hot gases flow through a turbine, causing a generator to generate energy.

A combined cycle power plant uses both the Brayton cycle (gas turbine) & the Rankine cycle (steam turbine) to increase overall efficiency. Waste heat from gas turbine is utilized to generate steam, which powers a steam turbine.

Advantages: Wind energy has the advantage of being renewable and emitting minimal levels of greenhouse gases. 

Disadvantages: The disadvantages include inconsistent generation, visual impact, & the necessity for appropriate wind resources.

Nuclear fission generates heat in a nuclear power plant, converting water into steam. The steam drives a turbine, which generates energy. Nuclear reactors burn uranium (or) plutonium as fuel.

Cogeneration systems generate electricity and useable thermal energy concurrently by utilizing technologies including 

  • Waste heat recovery, 
  • Trigeneration, and 
  • Combined heat & power (CHP).

Load flow analysis is a computer method for determining the steady-state operating (operational state) conditions of the power system. 

It computes 

  • Voltage magnitudes, 
  • Phase angles, and 
  • Power flows in the network.

Advantages: The advantages of distributed control system (DCS) include centralized control, increased automation, and greater monitoring capabilities. 

Disadvantages: The disadvantages include a higher initial cost & the requirement for specialized personnel for maintenance.

A generator’s magnetic field is controlled by an excitation system, which enables the generator to generate energy. An exciter, an automated voltage regulator (AVR), and related control devices are usually included.

Real-time power generation & load demand balance is maintained through the use of load frequency control. It supports 

  • Consistent power supply, 
  • Frequency control, and 
  • Grid stability.