Short Answer:
Lightning arresters are devices used to protect power systems from high voltage surges caused by lightning strikes or switching operations. They safely divert excess voltage to the ground, preventing damage to transformers, lines, and other equipment.
By limiting voltage spikes, lightning arresters maintain system reliability and prevent equipment failure, ensuring continuous and safe power supply.
Detailed Explanation:
Lightning arresters and power system protection
Introduction
Power systems are vulnerable to sudden high voltage surges primarily caused by lightning strikes and switching actions. These surges can cause insulation failure, equipment damage, and power outages. Lightning arresters are protective devices installed to limit such overvoltages and protect the system from these harmful effects.
Working Principle
- Lightning arresters are connected between the power line and ground.
- Under normal voltage, they remain non-conductive and do not affect the system.
- When a voltage surge exceeds a certain threshold, the arrester becomes conductive.
- It provides a low-resistance path to ground, safely diverting the surge away from sensitive equipment.
- After the surge passes, it returns to its high-resistance state.
Types of Lightning Arresters
- Horn Gap Arresters
- Use air gap as the spark gap.
- Simple but less reliable and less used today.
- Metal Oxide Varistor (MOV) Arresters
- Use zinc oxide blocks to limit voltage.
- Fast response, high energy absorption, widely used today.
- Silicone Rubber Arresters
- Lightweight and weather-resistant.
Installation Locations
- Near transformers, circuit breakers, and other critical equipment.
- At the ends of transmission lines to protect the line and connected equipment.
- At substations and distribution points.
Benefits
- Prevents insulation breakdown and equipment damage.
- Minimizes power interruptions and outages caused by surges.
- Increases system reliability and equipment lifespan.
- Reduces maintenance and repair costs.
Conclusion
Lightning arresters protect power systems by diverting dangerous high voltage surges to ground, preventing damage and ensuring continuous operation. Modern arresters like MOV types provide fast and reliable protection, making them indispensable for safe and stable power system operation.