Electrical Transmission & Distribution (ET&D) Essentials

Let's start by walking through the process of laying out a distribution feeder, from the substation down to residential meters in the fictitious town of TaylorTown.

You will also learn common distribution terms/nomenclature, and the typical values of voltage, current, and power throughout a distribution system.

This is an introductory level course - you are not required to have any prior utility power system knowledge, and no math is required.

Before we dive in, it helps to have a basic picture of how electricity actually gets to your customers. Power leaves a substation, travels along distribution lines, steps down through transformers, and arrives at the meter ready to use. Most solar installations connect somewhere in that final stretch — and because the system was originally designed for power to flow in just one direction, from the utility outward, understanding that basic flow helps make sense of a lot of the rules and requirements you'll run into on the job.

Solar changes things by sending power back the other way, and utilities have had to adapt their systems to handle that. Things like interconnection requirements, inspection checkpoints, and utility approval processes all trace back to real engineering considerations in the distribution system. As you work through this module, you'll start to see why those requirements exist — and that context will make you a sharper, more confident professional when you're working through project timelines and talking with utilities.

Transmission is the part of the grid most people never think about — but it's what makes the whole system work. When power is generated at a large plant or a utility-scale solar farm, it needs to travel long distances before it reaches anyone who can use it. To do that efficiently, voltage gets stepped way up so electricity can move across hundreds of miles of high-voltage lines without losing too much energy along the way. Those big steel towers and thick cables you see crossing the landscape? That's the transmission system doing its job.

For most solar professionals, transmission won't be something you interact with directly — residential and commercial installations connect at the distribution level, not the transmission level. But having a basic picture of how the broader grid is structured will help you understand where solar fits into the bigger energy conversation, and it becomes more relevant as you work on larger projects or start exploring utility-scale solar down the road. Think of this module as building the backdrop — so that everything else in the course has a little more context behind it.