Voltage Regulators 1

[BillyBob2021]

Hello,

What could cause a 333kva single phase GE voltage regulator to not tap up but only tap down? When placed in manual it will only lower not raise. When put in auto it will call to raise the motor will make noise but it will not tap up. If the capacitor was bad I would think it wouldn’t allow us to lower.

Another question how often should a single phase (7620) voltage regulator operate daily, monthly, yearly? Is there any articles or information about what is average and what is concerning?

Thanks

 

[waross]

Only one way and makes noise?
First check for mechanical issues.
It is possibly extreme wear in a gear set that is binding in one direction.
How often should it operate? That depends on the load profile.
With a mostly residential/farm load, the regulator will typically be stepping up for the breakfast peak, and then stepping back down after the peak.
In the afternoon, it will step up again for the supper peak and then step down.
As I said, it depends on the load profile.
Whenever a change in load causes more voltage drop than the dead band of the control circuit, the regulator should make a step.
I one customer has a motor or machine that draws enough current to drop the voltage more than the dead band, the regulator may step every time the motor is started.


--------------------
Ohm's law
Not just a good idea;
It's the LAW!

 

[BillyBob2021]

Thanks for the reply.

We have single phase regulators in our distribution substations some operate 2000 some 5000 times a month I’m just wondering if this would be considered concerning. I actually had (key word had) a regulator that operated almost 80,000 times in one year. Just wondering what is considered to much.

The regulator makes noise when lowering as well it makes the typical motor noise. It makes the typical motor noise when trying to raise but it doesn’t actually raise. We can only lower it.

 

[waross]

I would increase the dead band a little.


--------------------
Ohm's law
Not just a good idea;
It's the LAW!

 

[dpc]

If it won't raise in manual, I would suspect a mechanical issue or internal motor/wiring. Unless there are specific load fluctuations that would cause a lot of voltage swings, that seems like a high number of operations. As waross suggested, check the deadband settings as well as the minimum delay setting.

 

[stevenal]

We flag it at 1000 per month. Sounds like you may have some hunting going on. What's your bandwidth?

 

[cranky108]

I believe in some units the motor might need to reverse directions, and if so there would need to be a relay to swap the direction. That relay may be bad.
I have not worked on a voltage regulator, but I know what they are. So I am making a slightly educated guess.
Maybe if someone has worked on one it would be better to follow what they know.
I doubt there is a clutch and reversing gears, but if so that could be the mechanical issue.

 

[waross]

That relay may be bad.

Good catch cranky.
Possibly the most likely cause.

--------------------
Ohm's law
Not just a good idea;
It's the LAW!

 

[bacon4life]

Operating 5000 time per month is way too many. Stevenal's suggestion of flagging at 1000 per month sounds reasonable to me. Most of my regulators operate less than 10 steps per day during moderate weather/load conditions, but we have a fairly stable transmission voltage.