Grid Planning: Preparing for Customer Impacts on the Grid
Forty years ago, ARPANET was just getting off the ground. At that time, grid planning was built on the assumption that current and voltage decrease as power moves away from a substation. In this model, there was time for transformers and other equipment to cool overnight. Power flowed in one way. Moving load on the feeder solved any phase imbalance.
But now, none of these rules apply. Voltage will be higher near a solar generation installation. Electric vehicles (EV) and the internet of things (IoT) will drive overnight load increases, and energy storage is a wild card. Discarded alongside the old rules are mechanical regulators, decreasing conductor size, stepping voltage down, relay and protection settings, oil filled tap changers, and three-phase controls.
In this environment, customers are rethinking how they use electricity and when they are using it. Many common uses of electricity, such as lighting, are getting far more efficient, providing even larger swings in electricity use between when customers are active at home and when they are away.
The grid planner of the future will have to assume that load and supply can appear anywhere — that protection and voltage settings are adaptive, sometimes moving as many as 100 times a day on a single circuit. They will need to understand that phase imbalance can appear and disappear in minutes and that distributed generation is far more likely to appear in areas with larger lots and small farms.
Complicating this is the emergence of the “always on” lifestyle. Outages of a few minutes raise anger that would not have existed 20 years ago for an outage of an hour or more. Customers refuse to be disconnected from their internet. Reliability and resiliency at the distribution level requires planners to rethink the open radial design that has dominated distribution planning since the 1930s. New designs require loop and alternative schemes, jumping points, and undergrounding. Traditional wood poles will be replaced with concrete, composites and steel.
Customers will continue to install IoT-enabled devices, powered with “Alexa,” “Siri” and other voice-driven control systems. Pricing and complexity — features that put these devices out of reach for the average family — give way to affordability and simplicity. This will give the customer absolute flexibility to use energy only when they want to.
The majority of customers do not fully comprehend their impact on the grid, and many don’t care to know. Because of this, their impact will need to be anticipated by the planners of the future.
In the past 40 years, we have evolved from ARPANET to the IoT. Where will 40 more take us? If progress tells us anything, electric vehicles and grid diversity will be commonplace. The grid assets installed today must be designed to handle these coming changes.