Components of a Transformer
A transformer is primarily composed of the following core components:
Core
Function: Forms the main magnetic circuit of the transformer, conducting the alternating magnetic field.
Material: Typically laminated from silicon steel sheets (usually 0.27mm, 0.3mm, or 0.35mm thick) coated with insulating varnish to reduce eddy current losses.
Windings
Function: Constitute the electrical circuit part of the transformer, enabling power transfer and voltage transformation through electromagnetic induction.
Material: Usually wound from insulated copper or aluminum wire (e.g., enameled wire, paper-covered flat copper wire), divided into high-voltage windings and low-voltage windings.
Insulation and Cooling Medium
Insulation Materials: Include insulating paper, insulating varnish, insulating oil, etc., to ensure electrical insulation between windings and between windings and the core/tank.
Transformer Oil (for oil-immersed transformers): Serves the dual functions of insulation and cooling.
Cooling System: Includes radiators, cooling fans, etc., to dissipate heat generated during operation.
Tank and Mechanical Structure
Tank: Houses the active part (core and windings) and transformer oil, providing mechanical protection and a sealed environment.
Conservator (Oil Expansion Tank): Compensates for the expansion and contraction of transformer oil due to temperature changes, minimizing contact between oil and air.
Protective Devices
Gas Relay (Buchholz Relay): Installed in the oil pipe, it monitors gases generated by internal faults and triggers alarms or trip signals.
Pressure Relief Device or Bursting Disc: Relieves internal overpressure to prevent tank rupture.
Dehydrating Breather (Silica Gel Breather): Absorbs moisture from air entering the conservator to keep the oil dry.
Temperature Measuring Devices: Monitor the top oil temperature or winding hot-spot temperature of the transformer.
Voltage Regulation Device
Function: Adjusts the output voltage of the transformer without interrupting the power supply.
Type: Usually a tap changer, which can be either an off-circuit tap changer or an on-load tap changer.
Bushings
Function: Safely bring the high- and low-voltage leads from the internal windings out of the tank and connect them to external circuits, while ensuring reliable insulation to ground.
Summary: Through the coordinated operation of its core, windings, insulation system, cooling system, protective devices, and voltage regulation device, a transformer performs its core functions of voltage transformation, power transmission, electrical isolation, and system protection.