deadband

[royclh]

hi,

can anyone tell me how to determine the deadband of the tap changer correctly, given that the tap changer is +/- 12%, +/-6 steps (12 steps) 1%.

your help is greatly appreciated.

Many thanks

 

[redfurry]

The deadband is a setting which indicates how much the voltage has to change from the desired setting before the tap changer will operate. It cannot be determined by the range and number of steps. Normally it will be larger than the step size. So for a 1% step, it could be 1.5% to 2.5%

By the way, you indicate +/- 12% (a 24% spread) with 12 steps of 1%. This doesn't add up!

 

[jghrist]

I don't know if there are any hard and fast rules. The deadband or bandwidth has to be small enough that the voltage variation is not too great and small enough that the tapchanger doesn't operate too often.

 

[royclh]

sorry redfurry, it's a typo. Should be +/-12%, +/-6 steps (12 steps) 2%. Some suggests to have 1.5% or twice of the tap size.

If it is possible to calculate the absolute difference between upper limit voltage and the reference voltage, lower limit voltage and the reference to define the deadband limits, ignoring any hystersis term as described in the following link?

http://books.google.com/books?id=t3...CAoQ6AEwADgK#v=onepage&q=deadband tap&f=false

 

[magoo2]

In North America, the +/-16 step LTC or regulator is common with each step being 5/8%. It gives an over all regulation of +/- 10%. Two times the step size or 1.25% is commonly used for the deadband.

With a 2% step size, I'm not sure I would want to double it to get the recommended deadband. The taps may never change with that wide a deadband!

To start you might want to set it at 1.5 times the step or 3% and then monitor the number of operations in a month. Based on thhe number of operations, you can then adjust to a higher or lower value.

 

[slavag]

Im later.
Our practic.., exactly what magoo2 saied.

 

[royclh]

thanks for all comments. I appreciate that. It has been really helpful!!