Frequency power fluctuations

[markusjames]

Hello!
What's the implications on frequency fluctuations on 3 phase power?
From transformer to feed the lighting dimmer rack. We use Fluke power logger and recorded a frequency fluctuations from 50hz to 0hz in almost every 5 secs interval. It's random, different day and time. What may have caused this and possible solution? Thank you!

 

[pc1966]

Seeing 0Hz to me looks like the supply went off!

I guess you are having problems to put the power logger on in the first place, any more info?

 

[Mike Johnson]

I will plump for a loose connection?

 

[Strima]

Transformer windings failing is my guess.

 

[markusjames]

Hello!
Our Power logger data records that all 3 phases L1,L2,L3 has 230v but the frequency drops from 0Hz to 50hz in 5 seconds randomly.
Is this issue on the transformer? I would assume if there's no frequency there would be no voltage as well. Is this correct? Thank you!

 

[Wilko]

Hello!
Our Power logger data records that all 3 phases L1,L2,L3 has 230v but the frequency drops from 0Hz to 50hz in 5 seconds randomly.
Is this issue on the transformer? I would assume if there's no frequency there would be no voltage as well. Is this correct? Thank you!

Hi - weird behaviour ... can you tell us please what is the make and model?

 

[markusjames]

Hi - weird behaviour ... can you tell us please what is the make and model?

Make and model of the power logger? we use Fluke.

 

[stevels4]

Frequency is set at the point of generation and remains constant along the distribution network, have you tried a substitute tester? The last time the frequency fell less than 1.5hz the network automatically began shedding load after 2 power stations failed.

 

[KennyKen]

The Prime Mover Rotating equipment will have under frequency parameters too which would cause a SD. If it behaved in that manner.

 

[markusjames]

Thank you all. Can someone interpret the photo. Obviously, there's a fluctuation of frequency but want to know what can cause this and how to resolve?

 

[Wilko]

Thank you all. Can someone interpret the photo. Obviously, there's a fluctuation of frequency but want to know what can cause this and how to resolve?

Hi - can you post up the other plots too? Thanks

 

[markusjames]

Hi - can you post up the other plots too? Thanks

Here's the Good and Bad reading of the Frequency.

 

[wheeto]

I'm struggling a bit to read those plots, but the severity of the plots in your post #10 shows power cuts, not frequency fluctuations! From what I can read of those plots, you're getting 0Hz for minutes at a time. Suggest loose cable on meter?? As @pc1966 asked earlier, what caused you to measure, in the first place?

 

[markusjames]

I believe its not the loose connection from the power logger because its stationary and the logger is set to trigger every 10secs. And random readings on different times and days.
Reason for taking the reading is to prove where the issue from our Lighting dimmer with relays acting weird on/off during shows. We suspected that there's issue with the main transformer. But we need evidence where the issue lies.
Is it possible that only the Frequency fluctuations to 0hz and not the power voltage?

 

[wheeto]

Is it possible that only the Frequency fluctuations to 0hz and not the power voltage?

If you're connected directly to a tx, yes it's impossible. If you've got other circuitry involved then yes, the power could be rectified somehow. Most switch-mode power supplies would be just as happy with 300V DC, but .... I'd say it's one of the less-likely options