Okay kiddo, have you ever heard of something called NERC? It stands for North American Electric Reliability Corporation. NERC is a group of people who make sure that we have reliable electricity in North America. This means they make sure the power plants that make electricity and the power lines that carry it are working properly and not causing any problems.
Now, within NERC there is something called a TAG. TAG stands for Technical Advisory Group. A TAG is a group of experts who help NERC with different projects. They are like really smart helpers who know a lot about different things related to electricity.
For example, let's say NERC wants to make sure that the power plants that make electricity are safe and not harming the environment. They might ask a TAG of experts who know a lot about the environment to help them figure out what rules and regulations should be in place.
So basically, a NERC TAG is a group of really smart helpers who help NERC with different projects related to making sure we have reliable electricity in North America.