Maxim Integrated has a new online course available called the Fundamentals of Energy Management. The course is presented by one of Planet Analog's well-known bloggers and former EDN editor, Bill Schweber.
The course doesn't deal with power generation, but jumps in after that point. Starting with distribution, Bill dives in with a discussion of the energy management chain: the electrical grid, grid storage, automation of the distribution network, and access points (where the users connect).
He looks at residential and commercial distribution and the way smart energy management can be applied. At the access point, that means smart meters. Smart meters monitor all three phases of the incoming AC line for commercial customers; and the two halves of a “split” phase for residential customers. That means monitoring the voltage and current.
Some issues to consider: battery life if the meter had battery back-up (to retain info during power outages); security; accuracy (0.1 percent accuracy over a 2000:1 range of power draw).
Bill discusses consumption — an obvious topic at first — but there are details to consider. If you are charging an electric vehicle, power draw can be very high for short periods of time. The power company wants to know when this is happening so they can perform load-leveling.
If there are streetlights, it would be good to know if they are overheating, drawing too much current, or not enough. A smart grid enables all this functionality.
The smart grid functionality needs a communications network. It's composed of a variety of links — 300/1200 Baud data links (possibly RS232), power line communications (PLC), fiber optics, ZigBee, etc.
There are multiple reasons why we want all this interconnectedness on the power grid: to save energy, balance the various loads via load shedding, anticipate and report problems, and reconfigure the system when problems occur.
Bill also discusses the need for galvanic isolation for the power and the communications link. He discusses security issues. He notes that they are underappreciated until something bad happens. He gives an overview of why it's important and how to do it.
Bill talks about standards and regulatory issues. He discusses how some products must comply with minimal standards (such as a wall thermostat) while others need to comply with much more rigid standards (if connected to high voltage or have security issues). And he reminds us that not all reference designs have been compliance/regulatory qualified.
For convenience, Bill lists some of the communications networks we are likely to encounter:
- LAN: local area network;
- WAN: wide area network;
- HAN: home area network;
- NAN: neighborhood or near area network.
Be aware of the standards that are applicable. Know who defines the standards. Know whether they are proprietary or open. A couple to become familiar with are ZigBee (a.k.a. IEEE 802.15.4) and IEEE P1901.2 (for PLC).
Are you working on any smart grid applications? What challenges are you dealing with and how have you overcome them?