EHV Power Quality

[scottf]

I'm looking for some information on why power quality data (harmonics, etc...) would need to be obtained directly from HV/EHV/UHV lines.

I understand the need for PQ data, but I'm trying to understand why it would need to be measured on the high side of substations, etc...

I would be interested in anyone's experience with the in's and out's of taking such measurements, particularly in regards to the method of measurements, i.e. instrument transformers, etc...