1. Security
Prevent electric shock: The iron core of the transformer is generally made of highly conductive materials (such as silicon steel sheets). During normal operation, the core should be insulated from the ground. If the core is not grounded, it may become electrically charged in the event of insulation damage or leakage, increasing the risk of electric shock. By grounding, you can ensure that the core is maintained at ground potential in all circumstances, avoiding the risk of electric shock.
2. Protect the device
Prevent equipment damage: If the core is not grounded, there may be abnormal current or voltage fluctuations, which may lead to the aging of the internal insulation of the transformer and shorten the life of the equipment. Core grounding helps to stabilize the working state of the transformer and reduce the risk of equipment damage.
3. Reduce electromagnetic interference
Improved electromagnetic compatibility: A grounded core helps reduce electromagnetic interference, improves the electromagnetic compatibility of the transformer, and minimizes the impact of electromagnetic interference from the transformer on surrounding equipment and systems.
4. Fault current guide
Fault protection: In the event of a fault, such as an internal short circuit or insulation failure, a grounded core can help the fault current be smoothly imported to the ground, thereby reducing the damage to the transformer and surrounding equipment.
If the transformer core is not grounded, the suspended voltage of the core to the ground will cause intermittent breakdown and discharge of the core to the ground, which will not only damage the transformer, but also be very dangerous.
Question 2: How to ground transformer core?
1. Grounding system design
Select a grounding method: The grounding method should comply with local power regulations and standards. Common grounding modes include single point grounding and multi-point grounding. In general, the transformer core is grounded at a single point, that is, on one side of the core (usually close to the transformer housing).
2. Select ground cables
Cable specifications: The ground wire used should have sufficient electrical conductivity and mechanical strength, usually copper or aluminum wire, wire diameter should meet the relevant standards and design requirements.
3. Ground resistance
Ensure low resistance: The resistance of the grounding system should be as low as possible to ensure a good electrical connection between the core and the ground. It is usually required that the ground resistance is less than a certain standard value (such as less than 1 ohms) to ensure safety and equipment protection.
4. Connect ground cables
Connection method: Firmly connect the ground cable to the transformer core and the grounding system (such as the ground rod or grounding network). Ensure that the connection point is not corroded, not loose, and in good contact with the iron core.
5. Check regularly
Maintenance and inspection: Periodically check the integrity and resistance value of the grounding system to ensure that the grounding system works properly. If the grounding system is faulty, repair or replace related components in time.
Question 3: Why does the core allow only one point of grounding?
The core of the transformer allows only one point of grounding, not two points, and not many points of grounding. When the core is grounded at two or more points, the uneven potential between the core will form a circulation between the ground point, causing local overheating of the core, resulting in multi-point grounding heating failure of the core, and even burning the metal parts and insulation layer. At the same time, the local molten iron core will form a short circuit fault between the iron chips, which will increase the iron loss, seriously affect the performance and normal work of the transformer, so that the core silicon steel sheet must be replaced to repair, so the transformer does not allow multi-point grounding, there is and can only be a little ground.
