Short Answer:

A lubrication system in power plants is a mechanism that supplies lubricating oil to moving parts of machines such as turbines, pumps, and generators to reduce friction and wear. It helps in cooling, cleaning, and protecting components from corrosion and damage.

In simple words, the lubrication system ensures that all rotating and sliding parts move smoothly without direct contact. It maintains a thin oil film between surfaces, which prevents metal-to-metal friction, increases machine life, and ensures reliable and efficient operation of power plant equipment.

Detailed Explanation :

Lubrication System in Power Plants

The lubrication system in power plants plays a very important role in ensuring the smooth and efficient operation of mechanical equipment. Power plants use large machines like turbines, generators, pumps, and bearings that operate under high speed and load. Without proper lubrication, these components would experience high friction, leading to overheating, wear, and mechanical failure.

The lubrication system provides a continuous supply of clean lubricating oil at the correct pressure, temperature, and flow rate. The system also filters the oil, removes contaminants, and helps in cooling the components. Thus, it not only reduces wear but also ensures long-term reliability and safe operation of the power plant.

1. Purpose of Lubrication System in Power Plants:
   The main purpose of a lubrication system is to supply lubricating oil to moving parts of machinery to minimize friction and wear. In power plants, it serves the following functions:

• To reduce friction between moving surfaces.
• To cool components by carrying away heat.
• To clean and remove dirt, debris, and metal particles.
• To seal small gaps between components, preventing leakage of gases or steam.
• To protect metal parts from corrosion and oxidation.
• To improve efficiency and extend the life of machines.

Thus, the lubrication system is essential for maintaining performance, efficiency, and safety of all rotating and reciprocating equipment in power plants.

2. Components of Lubrication System:
   A typical lubrication system in power plants consists of several key components that work together to ensure proper oil flow and cleanliness.

• a) Oil Reservoir (Sump or Tank):
  Stores lubricating oil before it is circulated through the system.
• b) Oil Pump:
  Pumps the oil from the reservoir to various parts of the machinery under the required pressure.
• c) Filters:
  Remove dirt, dust, and metal particles from the oil to prevent damage to bearings and moving parts.
• d) Coolers (Heat Exchangers):
  Reduce the temperature of the oil by passing it through a cooler (usually water-cooled or air-cooled).
• e) Oil Piping and Valves:
  Carry lubricating oil from the pump to the machine components and return it to the tank. Valves regulate pressure and flow.
• f) Pressure Gauges and Temperature Sensors:
  Monitor the pressure and temperature of the oil to ensure proper operation.
• g) Strainers:
  Used at the suction side of pumps to remove large particles before the oil enters the main system.
• h) Bearings and Nozzles:
  Deliver oil directly to the surfaces where friction occurs, such as bearings, shafts, and gears.

All these components work together to provide a steady and clean supply of lubricating oil.

3. Working of Lubrication System:
   The working of a lubrication system involves the continuous circulation of oil throughout the equipment to reduce friction and maintain temperature.

1. Oil Supply:
   The lubricating oil is stored in a reservoir or sump located below the machinery.
2. Pumping:
   The oil pump draws oil from the reservoir and sends it through filters and coolers under pressure.
3. Distribution:
   The pressurized oil is distributed through pipelines and nozzles to all bearings, gears, and rotating parts.
4. Lubrication:
   A thin oil film forms between moving surfaces, preventing direct contact and reducing friction.
5. Cooling and Cleaning:
   As the oil circulates, it absorbs heat and carries away small particles or debris.
6. Return to Reservoir:
   After lubrication, the used oil flows back to the reservoir through return lines, where it cools and gets ready for recirculation.

This cycle continues as long as the machinery is running, ensuring continuous protection and lubrication of all critical parts.

4. Types of Lubrication Systems Used in Power Plants:

Different lubrication systems are used depending on the machinery design and operating conditions:

• a) Splash Lubrication System:
  Used in small engines or pumps where moving parts dip into the oil reservoir and splash oil onto other surfaces.
• b) Pressure (Force-Feed) Lubrication System:
  Oil is pumped under pressure to various components such as bearings and gears. Commonly used in turbines and large engines.
• c) Mist Lubrication System:
  Oil is converted into fine mist by compressed air and directed to moving parts, suitable for high-speed applications.
• d) Ring Lubrication System:
  Metal rings lift oil from the sump and deliver it to the bearing surfaces by rotation.
• e) Circulating Lubrication System:
  Common in large turbines and generators where oil is continuously pumped, cooled, and filtered before reuse.

Among these, the pressure and circulating lubrication systems are most commonly used in power plants due to their reliability and efficiency.

5. Functions of Lubricating Oil in Power Plants:
   Lubricating oil performs multiple functions apart from reducing friction:

• Cooling: Carries away heat produced due to friction.
• Cleaning: Removes impurities, dust, and metal particles.
• Sealing: Seals small gaps between moving surfaces.
• Corrosion Protection: Forms a protective layer to prevent rust.
• Shock Absorption: Reduces impact forces between gears or bearings.

Hence, the lubricant not only ensures smooth motion but also protects and maintains the machine’s overall health.

6. Importance of Lubrication System in Turbines and Generators:
   In power plants, turbines and generators operate continuously at high speeds. Their bearings and shafts require efficient lubrication to prevent metal contact and overheating.

• In steam turbines, oil lubricates bearings and also cools the shaft seals.
• In gas turbines, lubrication reduces wear in the high-temperature environment.
• In hydro turbines, it minimizes friction in guide and thrust bearings.
• In generators, lubrication ensures smooth rotation and minimizes vibration.

A failure in the lubrication system can cause severe damage, overheating, and costly downtime.

7. Maintenance of Lubrication System:
   To ensure proper functioning, regular maintenance of the lubrication system is essential. Maintenance activities include:

• Checking oil levels and topping up as needed.
• Replacing filters and cleaning strainers.
• Inspecting pumps and pipelines for leaks.
• Monitoring temperature and pressure gauges.
• Testing oil quality and replacing it when contaminated.
• Ensuring proper operation of cooling systems.

Regular maintenance prevents breakdowns and ensures long service life of machinery.

Conclusion:

The lubrication system in power plants is a vital part of machinery operation that ensures smooth movement, reduces friction, and prevents wear and overheating. It circulates clean, cooled oil continuously through bearings, shafts, and gears, maintaining efficient and safe working conditions. A properly designed and maintained lubrication system increases the reliability, efficiency, and lifespan of power plant equipment, making it an essential part of modern power plant operation and maintenance.