2400 volt to ground, voltage regulators

[mshields]

I've got a bank of 3 voltage regulators on a 4160/2400V system each connected phase to ground with 2400V to 120V PT's. Standard setting is for a voltage variance of +/- 2 volts maintained for 45 seconds, the voltage is corrected back to the nominal. I'm told that utilities typically set these for either a longer time delay or a greater voltage in order to reduce the number of times that the regulator has to change states.

What I don't know, is what is advisable?

Would appreciate your input.

Thanks,

Mike

 

[Bugman1400]

What you stated is the advisable.....2 volts (40 volts primary) and 45 second delay. The regulators should not top out (boost) or bottom out (buck) except under extreme conditions.

 

[Tony S]

I’ve never set tap changers to less than 30s per step.

The only time our tap changes really came in to play was at the weekends. Our load dropped dramatically as did other industrial sites nearby. The 33KV incoming could rise by 6/7% so our 33/11KV transformer/tap changers got to do some work.

If anyone has ever stood beside one when it changes taps it sounds like its being violently sick, the reactors growl. It’s the only way I can describe it. The first time I heard it I wondered what the hell was going on, it frightened me.

 

[george89]

You can put your settings at automatic mode and the regulator will do the job. The parameters such as line resistances, and the reactance allow the regulator to estimate the voltage at the load. The regulator when in automatic mode controls the tap changer in order to keep the load voltage within an optimum interval.

Regards,
George
http://blog.7pcb.com

 

[Bugman1400]

You can put your settings at automatic mode and the regulator will do the job. The parameters such as line resistances, and the reactance allow the regulator to estimate the voltage at the load. The regulator when in automatic mode controls the tap changer in order to keep the load voltage within an optimum interval.

Regards,
George
http://blog.7pcb.com

Are you talking about droop settings? I think most regulators regulate the local bus and the voltage at farthest load is taken into account when the calcs are done as not to go below 95% pu.