A lot of utility companies who are facing harmonics issues generated by customers are taking a new approach.
They install protective relays that measure the harmonics and have penalties in their service contracts. I've heard of some that disconnect a customer who is contirbuting high levels of harmonics, and others that charge them fines whent hey cross certain thresholds.
Devices that can measure this are now quite inexpensive, and it seems a reasonable way to go.
