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Balance in all phases

Doug Houseman's picture
Visionary and innovator in the utility industry and grid modernization Burns & McDonnell

I have a broad background in utilities and energy. I worked for Capgemini in the Energy Practice for more than 15 years. During that time I rose to the position of CTO of the 12,000 person...

  • Member since 2017
  • 239 items added with 83,851 views
  • Nov 24, 2021

One of the issues that has become far more complex to deal with as PVs and EVs roll out is phase imbalance on the distribution grid.

Since the US grid (and others that copied the design) runs a single phase down a street, what happens on that street impacts that phase, and with it the balance of the circuits across the three phases.

The old way of fixing phase imbalance was to move load from one phase to another in the 3 phase portion of the circuit. Typically, the phase imbalance was constant over the daily cycle and so moving a transformer or two (and the attached customer load) solved the problem.

Now with PV the load decreases on that phase during the day and with EV’s it increases at night, on smaller lower voltage circuits it only takes a few households to cause a phase imbalance that changes from too little load in the daytime to too much load at night.

My wish is for a solid state 3 phase transformer that would be low enough cost and small enough in size that it could move energy from phase to phase as needed.

Linemen could stop moving transformers, and planners could stop worrying about what loads to change. In most cases this would be lower cost than running all three phases on every pole (or underground duct).

The device would reduce harmonics, remove flicker, and fix high and low voltage issues, in addition to fixing the phase imbalance.

The good news is that 3 years ago, such a program (and far more) was started by the Department of Energy at Oak Ridge, this is one possible device out of that work.

My wish is that the DOE continue to fund this work, so that we can eventually get this and other holiday presents that the grid really needs to be able to transform over the next decade or two. 

Bob Meinetz's picture
Bob Meinetz on Nov 24, 2021

Good info, Doug. Any idea where we might find more information on the DOE work at Oak Ridge? Seems this phenomenon, if unaddressed, could have a significant (and negative) impact on grid efficiency in coming years.

Doug Houseman's picture
Thank Doug for the Post!
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