Distribution Grid Fundamentals: How the Electric Grid Is Built and Protected

How the distribution grid is built, powered, and protected. The working fundamentals every buyer and new engineer needs.

1. 1 What the Distribution Grid Does The job of the distribution grid and where it sits between the substation and the meter. 6 min
2. 2 Voltage Levels and Why They Step Down Why power travels at high voltage and steps down in stages before it reaches a customer. Builds on the lesson above. That order will make more sense, but you can read this now. 7 min
3. 3 How the Grid Protects Itself Faults, the devices that clear them, and why a recloser tries again before it gives up. 7 min
4. 4 Overhead vs Underground Distribution Why some lines hang on poles and others run in the ground, and what each choice costs. 6 min
5. 5 Single-Phase and Three-Phase Why the grid uses three phases, and where single-phase taps off to serve homes. 7 min
6. 6 Feeders, Laterals, and Taps The shape of a radial feeder: a three-phase backbone, single-phase laterals tapping off it, and the normally-open tie that lets a neighbor feeder back it up. 8 min
7. 7 The Service Drop and the Meter The last few feet: from the service transformer to the meter and into the building. 6 min
8. 8 Conductors and What Limits Them Why a conductor has a current limit, and what ampacity depends on. 7 min
9. 9 Measuring Reliability How utilities measure outages with SAIDI and SAIFI, and what each one tells you. 7 min