Today on the Nanaimo HF net¹⁾, Devan (VE7LSE) mentioned this page to get in touch with BC hydro to report RFI from their transformers power distribution system. Apparently, RFI is something BC Hydro wants to know about because it's often a symptom of faulty equipment that cost them power losses (and therefore $$).

Update:

QRZNow just published an article about the MFJ-5008, an ultrasonic receiver with parabolic dish that's “tuned to the ultrasonic range of 40 KHz allowing you to hear the ultrasonic noise generated by the corona discharge and arcing connections that generate the power line static on your radio.”