Transformer Tap Settings
Transformer Tap Settings
(OP)
Hey everyone,
I am looking into adjusting a tap on your 110MVA Main step up transformer. I know the voltages are a direct correlation to the turn ratios. The issue we are having is the voltage on the low-side is getting to high, forcing inverters to trip since they are out of their voltage operating range. The Tap is currently set to neutral. It is a automatic load tap transformer however we are having issues with the automatic adjustments, therefore will set to a single tap setting.
What else should i look at inorder to determine the optimal tap setting. I have low side and high side voltages for the past week but are there any other equations that will fine tune my selection besides Vp/Vs = turns ratio = corresponding tap setting?
I am looking into adjusting a tap on your 110MVA Main step up transformer. I know the voltages are a direct correlation to the turn ratios. The issue we are having is the voltage on the low-side is getting to high, forcing inverters to trip since they are out of their voltage operating range. The Tap is currently set to neutral. It is a automatic load tap transformer however we are having issues with the automatic adjustments, therefore will set to a single tap setting.
What else should i look at inorder to determine the optimal tap setting. I have low side and high side voltages for the past week but are there any other equations that will fine tune my selection besides Vp/Vs = turns ratio = corresponding tap setting?






RE: Transformer Tap Settings
RE: Transformer Tap Settings
RE: Transformer Tap Settings
Along with this there is other system conditions to consider like weather or not the utility voltage is high/low, etc...
RE: Transformer Tap Settings
To determine an optimal setting for a fixed tap, determine the high side average voltage and put the tap in the middle of the operating band, that should get the 34.5kV to mid band. If the 34.5kV voltage goes consistently too high raise the HV one tap at a time until it gets to a band the plant can live with.
RE: Transformer Tap Settings
If the tap changer is trying to control voltage on the 138kV side, it will not be able to move the voltage much since it is pushing against the whole utility system. The controller is probably monitoring the 34.5 kV bus and trying to control the 34.5 kV voltage. But that voltage is also controlled by the inverter output voltage controller and affected by the amount of kVAR's flowing through the system. Usually the solution is to turn off the tap changer control during generation.
You best bet is to model the system in ETAP or Easy-Power, run a few simulations over a range of full power out to minimum power at various utility voltages and pick the best compromise.
RE: Transformer Tap Settings
RE: Transformer Tap Settings
RE: Transformer Tap Settings
RE: Transformer Tap Settings
Many years ago, in India, when under voltage was a perennial problem at distribution end, we used to make DTs (1MVA 33kV) with 20%tap range, locally made OLTCs.