A Buchholz relay is like a special switch that helps protect big machines like transformers. When a big machine like a transformer has oil in it, sometimes things can go wrong and gas or bubbles can form in the oil. This can cause a problem called a "fault" which can damage the machine. The Buchholz relay helps detect this problem by performing two important jobs:
1. When gas or bubbles form in the oil, the relay senses them and sends an alarm signal to alert workers that something is wrong.
2. If too much gas or bubbles build up, the relay automatically switches off the machine to help prevent damage.
So, the Buchholz relay is like a little superhero that helps keep big machines safe by telling people if there's a problem and turning off the machine if things get too dangerous.