Why does excitation inrush current occur when a transformer is energized with no load?
Why does excitation inrush current occur when a transformer is energized with no load? When a transformer is energized with no load, the excitation current immediately undergoes a transient phase, and its peak value may exceed several times the rated load current. Compared to the normal excitation current, the steady-state...
What are the inspection tasks for dry-type transformers?
What are the inspection tasks for dry-type transformers? Check for abnormal sounds and vibrations. Look for signs of local overheating, such as insulation surface tracking and discoloration caused by harmful gas corrosion and carbonization. Verify if the transformer's air-cooling system is operating correctly. Ensure that there is no overheating at...
Why is it necessary to ground the transformer core? And why is it not advisable to use a multi-point grounding approach?
Why is it necessary to ground the transformer core? And why is it not advisable to use a multi-point grounding approach? The core and its metal components generate different potentials due to their positions in the electric field. When the potential difference between two points reaches a level sufficient to...
How to analyze and dissect three-phase transformers?
How to analyze and dissectthree-phasetransformers? A transformer is a device that transforms AC voltage, current, and impedance. When an AC current flows through the primary coil, an alternating magnetic flux is generated in the core (or magnetic core), inducing voltage (or current) in the secondary coil. With the continuous development...
What protective devices does a three-phase transformer have?
What protective devices does a three-phase transformer have? Microcomputer Protection Device: The microcomputer protection device for three-phase transformers consists of highly integrated components, chip-on-bus single-chip micro-controllers, high-precision current-voltage transformers, high-insulation-strength output intermediate relays, high-reliability switch power modules, etc. The microcomputer protection device is mainly used for power plants, substations, distribution...
How to choose the cooling method for oil-immersed and dry-type forced air-cooled transformers?
How to choose the cooling method for oil-immersed and dry-type forced air-cooled transformers? Oil-immersed forced air-cooled transformers offer two selectable cooling methods: oil-immersed forced air cooling (ONAF) and oil-immersed self-cooling (ONAN). Generally, ONAF cooling is chosen when the transformer operates at 100% rated capacity, while ONAN cooling can be selected...
Why is vacuum drying and impregnation necessary for windings?
Why is vacuum drying and impregnation necessary for windings? Drying the winding helps to remove moisture from the insulation components. This not only enhances the insulation's withstand voltage level but also causes the insulation to contract to its inherent dimensions, providing accurate and reasonable data about the winding's axial height...
What are the main insulation and longitudinal insulation in a winding?
What are the main insulation and longitudinal insulation in a winding? The main insulation in a winding includes components such as the paper cylinder, wooden cylinder, winding end insulation, and the insulation between the static ring and the ground. These elements collectively form the primary insulation system of the winding....
What is a split winding? What are its requirements?
What is a split winding? What are its requirements? A split winding refers to the division of the low-voltage winding of a transformer into multiple parts that are electrically independent. These divided low-voltage winding sections are each connected to two generators, allowing each generator to operate independently or simultaneously. In...
In an interleaved manner, how is the leakage flux of the winding distributed, and what kind of electromagnetic force is generated?
In an interleaved manner, how is the leakage flux of the winding distributed, and what kind of electromagnetic force is generated? In the case of a winding arranged in an interleaved manner, the distribution of leakage flux is different from the concentric arrangement mentioned earlier. The predominant type of leakage...
In concentric arrangement, how is the distribution of leakage flux in the windings and the resulting electromagnetic forces explained?
In concentric arrangement, how is the distribution of leakage flux in the windings and the resulting electromagnetic forces explained? For double-winding concentric arrangement, the leakage flux is generally smaller than in a single concentric arrangement, and it is even further reduced in multi-winding concentric arrangements. Let's take the example of...
What is the main magnetic flux? What is the leakage magnetic flux?
What is the main magnetic flux? What is the leakage magnetic flux? When a winding in a transformer is connected to a power source, it generates a magnetic flux in the core. The magnetic flux generated in the core due to the excitation voltage is called the main magnetic flux,...
