Transformers are typically protected against lightning strikes through a combination of measures that aim to minimize the risk of damage and ensure the safety and reliability of the transformer and the electrical grid. Some of the key protective measures include:

  1. Lightning Arresters: Lightning arresters, also known as surge arresters or lightning rods, are installed on transformer units and substations. They are designed to intercept lightning strikes and divert the resulting electrical surge away from the transformer. These devices provide a low-resistance path to ground for the lightning current, protecting the transformer from potential damage caused by high voltage transients.

  2. Grounding System: Transformers are grounded to provide a path of least resistance for electrical current, including lightning strikes. Proper grounding helps to dissipate the energy from lightning strikes and prevents excessive voltage buildup in the transformer. Grounding also helps to protect personnel working on or around the transformer from electric shock hazards.

  3. Shielding and Insulation: Transformers are designed with proper shielding and insulation to minimize the risk of lightning-induced damage. Insulating materials, such as oil or solid dielectric, are used to isolate the transformer windings and core from external electrical disturbances, including lightning.

  4. Overvoltage Protection Devices: Overvoltage protection devices, such as surge protectors or voltage limiters, are often installed in transformer circuits. These devices detect and divert excessive voltage surges, including those caused by lightning strikes, away from sensitive transformer components, preventing damage. They also help to maintain the voltage at safe levels and ensure the integrity of the transformer insulation.

  5. Comprehensive Maintenance: Regular maintenance and inspections are essential to ensure the proper functioning of transformer protection systems. This includes checking the grounding system, inspecting lightning arresters for damage or degradation, and verifying the condition of insulation materials. Any necessary repairs or replacements should be carried out promptly to maintain the effectiveness of the protection measures.

  6. Location and Elevation: Transformers are sometimes placed in elevated positions or on raised platforms to reduce the likelihood of direct lightning strikes. Additionally, transformers may be positioned away from tall structures, trees, or other objects that could increase the risk of lightning strikes or falling debris during severe weather conditions.

  It is important to note that the level of lightning protection may vary depending on factors such as the size and location of the transformer, the level of exposure to lightning activity in the area, and local regulations and standards. Therefore, specific lightning protection measures for transformers should be determined based on a comprehensive risk assessment and compliance with applicable codes and guidelines.