Substation and Power Plant DC, for control and protection
Substation and Power Plant DC, for control and protection
(OP)
Dear Colleagues.
What type of DC power supply for the control and protection are used in your substations and power plants?
Our standard is floating DC batteries with on-line grounding monitor on "-" and "+" poles.
Are some one has experience with "-" grounded pole batteries?
Thanks in advance.
Slava
What type of DC power supply for the control and protection are used in your substations and power plants?
Our standard is floating DC batteries with on-line grounding monitor on "-" and "+" poles.
Are some one has experience with "-" grounded pole batteries?
Thanks in advance.
Slava






RE: Substation and Power Plant DC, for control and protection
Suspect issues with galvanic corrosion if grounded.
Gunnar Englund
www.gke.org
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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
RE: Substation and Power Plant DC, for control and protection
David Castor
www.cvoes.com
RE: Substation and Power Plant DC, for control and protection
Thanks a lot for your answers.
Gunnar, a try found some information about corrosion issue.
Are you have some documents?
Best Regards.
Slava
RE: Substation and Power Plant DC, for control and protection
We here also use floated DC batteries with control of insulation of poles. Typically batteries are 220 V DC. Only for small substations for private owners we try to push 110 V DC, which according to me is sufficient with numerical relay protections.
But I met one exception. After rehabilitation of industrial power plant new owner of the plant - Belgian company Solvay - insisted that negative pole to be permanently grounded. Their project manager didn't accept any discussions stating that in all installations of Solvay around the world it is the same practise.
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It may be like this in theory and practice, but in real life it is completely different.
The favourite sentence of my army sergeant
RE: Substation and Power Plant DC, for control and protection
Thanks a lot!!!!
Its really intresting information.
We try found those exceptions and understand what is a reasons for it, what is advantages and disadvantages, what type of monitoring is used, are used two pole MCB's or single pole MCB's, etc..
Best Regards.
Slava
RE: Substation and Power Plant DC, for control and protection
I have seen both floating and resistive centre-point earthed systems in substations but never a scheme with a solidly grounded pole.
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If we learn from our mistakes I'm getting a great education!
RE: Substation and Power Plant DC, for control and protection
As far as I remember (this project was some 3-4 years ago) they used two-pole MCB's.
Main reason to use grounded pole was that in case of damaged insulation on positive pole MCB will trip and it will be clear on which circuit the leakage is. According to me this is not so good idea, but it was not my design...
Of course they used control only from positive pole, but for 110 kV and 6,3 kV level it is still sufficient.
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It may be like this in theory and practice, but in real life it is completely different.
The favourite sentence of my army sergeant
RE: Substation and Power Plant DC, for control and protection
Not everybody does this. My present employer's "engineering" staff just gets glassy-eyed thinking about it when I mention it as a way to stave off DC ground problems.
old field guy
RE: Substation and Power Plant DC, for control and protection
Communication sites where they do not have many raccons, and 48vdc or less often ground the positive terminal, so it will blow the fuse.