40 Questions
What is the purpose of the air intake system in a diesel power station?
To remove dust particles from the air
What is the function of the cooling system in a diesel power station?
To keep the temperature of the engine parts within safe operating limits
What is the purpose of the lubricating system in a diesel power station?
To minimize the wear of rubbing surfaces of the engine
What type of generator is used in a diesel power station?
Salient pole type synchronous generator
What is the function of the choke in an alternator excitation unit?
To adjust the terminal voltage at no load
What is the purpose of a UPS (Uninterruptible Power Supply)?
To provide backup power during mains failure
What is the process by which a UPS works?
Converting AC to DC and then back to AC
What is the purpose of the rectifier in a UPS?
To convert AC to DC
What is the primary factor to consider when sizing a UPS battery?
Backup time
What is the purpose of considering redundancy in a UPS system?
To ensure system reliability
What is the main difference between Lead Acid/Calcium and Lead Acid/Calcium, Maintenance-free Gelled Electrolyte, Sealed Battery?
Maintenance requirements
What should be considered when selecting a UPS topology?
Application sensitivity to power interruptions
What is the purpose of evaluating the efficiency of a UPS?
To minimize energy costs and environmental impact
What should be considered when selecting a battery type?
Energy density, cycle life, and maintenance requirements
What is the purpose of considering the form factor of a UPS?
To ensure the UPS fits within the available space
What should be evaluated when selecting battery banks?
Battery type, capacity, autonomy, charging time, and temperature considerations
What is the primary function of the diesel engine in a diesel power station?
To burn diesel and produce mechanical energy
Why are diesel power stations used despite having a higher generation cost?
Because they are suitable for places with limited demand and resources
What is the primary function of a UPS?
To supply power to the equipment during input power interruptions
What is a major advantage of diesel power stations over steam power stations?
They have a lower overall cost
What is the main advantage of a UPS over other immediate power supply systems?
It provides immediate protection against input power interruptions
What is a disadvantage of diesel power stations?
They have high running charges due to costly fuel
Where are diesel power stations often used as standby sets?
In important locations such as hospitals and radio stations
What is the purpose of a flywheel in a UPS?
To store energy
What is the transfer time of an Off-line UPS?
About 25 milliseconds
Why do diesel power stations occupy less space?
Because they have a small number of auxiliaries
What is the main difference between an Off-line UPS and a Line Interactive UPS?
The addition of a tap-changing transformer
What is a characteristic of diesel power stations?
They have a high thermal efficiency
What is a limitation of diesel power stations?
They do not work satisfactorily under overload conditions for a longer period
What is the purpose of the rectifier in an On-line UPS?
To convert AC to DC for storage
What is the advantage of an On-line UPS over an Off-line UPS?
It has a shorter transfer time
What is the purpose of the tap-changing transformer in a Line Interactive UPS?
To change the tap depending on input voltage
What is an important consideration when selecting battery banks?
The physical size and weight of the battery
Why is it important to implement a battery monitoring system?
To track the health and performance of the batteries
What is a key aspect of ensuring the reliability of the backup power system?
Ensuring seamless integration between the UPS and battery banks
Why is it important to adhere to local codes and regulations?
To ensure safety and compliance
What is the purpose of developing a testing and maintenance schedule?
To verify the functionality of the UPS and battery banks
What is a recommended approach when selecting UPS and battery banks?
To consult with a professional or work closely with a reputable supplier
What is an important safety consideration when implementing a backup power system?
Proper ventilation for batteries
Why is it important to check the warranty provided by the battery manufacturer?
To assess the expected lifespan and replacement costs
Study Notes
Diesel Power Station (DG Set)
- A generating station that uses a diesel engine as the prime mover for generating electrical energy.
- The diesel engine drives an alternator, which converts mechanical energy into electrical energy.
- Advantages:
- Simple design and layout
- Occupies less space
- Can be located anywhere
- Quick start-up and load pick-up
- No standby losses
- Less water required for cooling
- Lower overall cost compared to a steam power station of the same capacity
- Higher thermal efficiency
- Requires less operating staff
- Disadvantages:
- High running charges due to costly fuel (diesel)
- Unsatisfactory performance under overload conditions for a long period
- Limited to generating small power
- High cost of lubrication
- High maintenance charges
Schematic Arrangement of Diesel Power Station
- Auxiliaries:
- Fuel supply system
- Air intake system
- Exhaust system
- Cooling system
- Lubricating system
- Engine starting system
- Diesel generator set: a salient pole type synchronous generator, self-excited and self-regulated by an excitation unit
Uninterruptible Power Supply (UPS)
- A device that maintains a continuous supply of electrical power, even in the event of a mains (utility) supply failure.
- Installed between the mains supply and the equipment to be protected.
- Uses: safeguarding computers, data centers, and critical equipment in large organizations.
- Working principle:
- Converts mains AC supply to DC voltage
- Charges batteries during normal operation
- Uses DC voltage from batteries to supply power during a mains failure
- Converts DC voltage back to AC voltage using an inverter
- Advantages: immediate protection against input power interruptions, short battery run time, and safe shutdown of connected equipment
Types of UPS
- Off-line UPS (Standby UPS system):
- Primary source is the filtered AC mains
- Transfer switch selects the backup source during a power breakage
- Least expensive UPS system, provides surge protection and backup
- On-line UPS:
- Double conversion method: AC input is converted to DC for storage, and then converted back to AC for the load
- Used where electrical isolation is mandatory
- More expensive due to the design of constantly running converters and cooling systems
- Line Interactive UPS:
- Used for small business and departmental servers
- Similar to off-line UPS, but with the addition of a tap-changing transformer for voltage regulation
- Provides additional filtering and lower transient loss
Battery Types
- Lead Acid/Plante Battery
- Lead Acid/Antimony Battery
- Lead Acid/Calcium Battery
- Lead Acid/Calcium, Maintenance-free Liquid Electrolyte Battery
- Lead Acid/Calcium, Maintenance-free Gelled Electrolyte, Sealed Battery
- Lead Acid (Special Alloy), Suspended Electrolyte, Maintenance-free, Sealed Battery
- Nickel Cadmium, Pocket Plate Liquid Electrolyte Battery
Battery Sizing
- Manufacturers provide sizing information for their batteries
- Battery sizing is typically done using watts per cell or amperes per cell
- Watts per cell method: uses kilowatts per cell tabulated for various backup times
- Amperes per cell method: uses charts expressed in available amps for specified periods of time
Selection of UPS and Battery Banks
- Key considerations:
- Power capacity (kVA or kW)
- Topology (Online Double Conversion, Line Interactive, Standby)
- Redundancy
- Scalability
- Efficiency
- Compatibility
- Monitoring and management
- Form factor
- Battery type (VRLA, lithium-ion)
- Capacity and autonomy
- Charging time
- Temperature considerations
- Maintenance requirements
- Footprint
- Monitoring system
- Warranty
- Integration and compatibility
- Safety
- Testing and maintenance schedule
This quiz covers the basics of diesel power stations, also known as DG Sets, which use diesel engines as prime movers to generate electrical energy. Learn about the combustion process and how it produces mechanical energy.
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