ЁЯМмя╕П Types of Cooling, Protective Devices, Bushings and Termination ЁЯМмя╕П
ЁЯзК Types of Cooling Methods for Transformers
Cooling is essential for transformers to prevent overheating and ensure reliable operation. The main types of cooling are:
- Air Natural (AN) ЁЯМмя╕П: Natural air circulation cools the transformer. Used for small transformers.
- Air Blast (AB) ЁЯМкя╕П: Forced air through blowers or fans for high rating transformers.
- Oil Natural Air Natural (ONAN) ЁЯЫвя╕ПЁЯМмя╕П: Oil circulates naturally inside and transfers heat to air naturally outside.
- Oil Natural Air Forced (ONAF) ЁЯЫвя╕ПЁЯТи: Oil circulates naturally but air is forced with fans to cool the radiator.
- Oil Forced Air Forced (OFAF) ЁЯЪА: Oil and air both are circulated forcibly using pumps and blowers.
- Oil Forced Water Forced (OFWF) ЁЯЪ░: Oil is circulated by pumps and cooled through water-cooled heat exchangers, used in large power transformers.
ЁЯЫбя╕П Protective Devices Used in Transformers
Various protective devices are used to ensure the safety of transformers:
- Buchholz Relay ЁЯЪи: Gas and oil operated relay for internal faults in oil-immersed transformers.
- Pressure Relief Device ЁЯТг: Relieves internal pressure build-up by venting out oil and gases.
- Oil Level Indicator ЁЯУИ: Indicates the oil level to avoid running dry.
- Temperature Indicators ЁЯМбя╕П: Monitors winding and oil temperature.
- Breather ЁЯМля╕П: Silica gel filled device to remove moisture from air entering the conservator tank.
- Surge Protectors/Lightning Arresters тЪб: Protects transformer from high voltage spikes due to lightning or switching surges.
ЁЯФй Bushings in Transformers
Bushings are insulated devices that allow current to safely pass through the grounded transformer tank wall.
Types of Bushings:
- Porcelain Bushings ЁЯП║: Made of porcelain and filled with oil or air, suitable for outdoor use.
- Resin Bonded Bushings ЁЯз╡: Resin material with mechanical strength, used for indoor applications.
- Capacitor Bushings ЁЯзп: Designed to control electric stress in high-voltage applications.
ЁЯФМ Termination Methods
Termination refers to connecting transformer terminals to external conductors safely and efficiently.
Types of Terminations:
- Indoor Termination ЁЯПа: Used inside switchgear, control panels, and substations.
- Outdoor Termination ЁЯМ│: Designed to withstand environmental conditions like rain, dust, and UV radiation.
- Heat Shrink Termination ЁЯФе: Shrinkable tubes used to insulate and seal cable ends.
- Cold Shrink Termination тЭДя╕П: Pre-stretched rubber sleeves that contract onto the cable when installed.
ЁЯза Conclusion
Proper cooling, reliable protection devices, strong bushings, and efficient termination are critical to the safe and efficient operation of transformers. Their correct selection and maintenance ensure long transformer life and reliable power supply. тЪбЁЯФз