I have some very high resolution data showing voltage on a D/Y 230kV to 13800 (nominal taps) as well as load, reactive power, etc. I show RMS voltage at the substation secondary moving between 13,440 (4 taps below nominal) and 13,890 (one tap above nominal) in the presence of gently varying load. Thing is I can't point to actual tap change events. What I think is that even though the voltage is varying (because of power flow), i don't think I have a single tap change event recorded. Does this sound about right?