On 13.8 kv circuit we've had customer complaints of blinking lights. After visually inspecting the circuit the only unusual condition was a 3 phase pole top capacitor bank (with Beckwith M-2501B Autodaptive control) installed one pole span downstream of 3 single phase line regulators.
I'm...
At two different stations, I took phase angles from A phase PT on 115kv bus to A B & C metering PTs on 13.8kv bus. I used a Dranetz Phasemeter - model 314. Both transformers are Dy1 and grid is A-B-C CCW.
The station with A-B-C sequence read:
HV A leads LV A by 32 deg
HV A leads LV B by 152...
Am I correct that simply overlaying vectors on transformer nameplates will indicate the phase shift from primary to secondary? Is this true of all transformers nameplates - Dy5, Dy11, Yd1, Yd5, Yd11, etc...?
For example, a Dy1 vector diagram from one of our 115D/13.8Y transformers - if you...
An incorrect switching order was issued by dispatch that would have left two 50 MVA LTC Transformers tied together through the 13.8 kv bus tie switch. Fortunately the field techs caught the error before carrying out the order.
They were speculating about the damage that this could cause if the...
Below is an email I sent to engineering after changing out a bad MW Transducer in one of our stations. I got this data off our server (TOIS) that night via VPN. The XFMR is 30 MVA (161kv/13.8kv) and Regulator is 3333 KVA 10% Raise and Lower. Were all kind of scratching our heads thinking...
