Typhoon HIL: Simplify Microgrid Control Design, Testing, and Commissioning

Micro grids have been around for as long as the electric generator. Indeed, before we built a highly centralized grid, electricity was generated, distributed, and used in small micro grids. And interestingly enough, these very first micro grids were DC micro grids.

They were built by Thomas Edison in New York City, prior to Tesla’s introduction of multi-phase alternating currents (AC) that changed the electricity generation, distribution, and consumption for good.

Today’s micro grids are very different. They are driven by our society’s quest for sustainable and renewable power generation, the need for a more flexible, versatile, and resilient power system, and the ability to effectively control power flow with power electronics converters.

There are three main types of micro grids:

Customer micro grids (what we all consider as “standard” micro grids)
Utility distribution micro grids
Remote micro grids.

Customer micro grids are true micro grids that are self-controlled subsystems connected to the grid downstream from a point of common coupling (PCC). Utility distribution microgrids are distribution subsystems, part of the regulated grid, that are owned and operated by a utility with the goal of helping the utility manage DER portfolios and improve reliability on the network. Remote micro grids (power systems) are islanded power systems that never operate in grid tied mode.

Here we focus on the grid tied micro grids that can operate both in the islanded and grid-tied modes.

Micro grid control requirements

Micro grids are complex systems since they have to provide all the functions of a large grid, including dynamic control and stabilization, yet with a much simpler control infrastructure, smaller number of generators, and significantly smaller system inertia.

The dynamics of modern micro grids span time constants ranging from microseconds to seconds and all the way to minutes and hours. While the utility grid has a much larger set of resources available for grid control and stabilization, micro grids are expected to achieve the same power quality with a drastically smaller number of energy resources and often with large penetration of intermittent power sources (PV, wind etc.).

And this is why control and stabilization of micro grids is complex.

Microgrids are expected to provide a subset of the 6 key functions: