Time synchronisation of IEDs
Time synchronisation of IEDs
(OP)
We use time synchronising of the relays via DNP3 protocol as most of our IEDs are connected via DNP3 over ethernet LAN.I am told that this method of time synchronising is not very accurate(+/- 10 ms?) and bit non deterministic depending on network traffic.I would like to hear your views on pros and cons of time synchronising of IEDs via DNP3 protocol versus via IRIG B signal.
Regards,
Regards,






RE: Time synchronisation of IEDs
In my opinion IRIG is a better and simpler approach. You connect to the source and it works. I understand having to run coax along with the cat5 is more wiring, but there is not much to screw up in the coax(rg-58) connections.
RE: Time synchronisation of IEDs
...or so you'd think. I've seen multiple installers struggle with crimping the terminals onto the coax cable!
RE: Time synchronisation of IEDs
RE: Time synchronisation of IEDs
RE: Time synchronisation of IEDs
For 1 ms accuracy, I think you will have to go with IRIG. If the device has an IRIG input, it would be an easy decision for me. The cost of the GPS time clocks gets lower every day it seems.
David Castor
www.cvoes.com
RE: Time synchronisation of IEDs
With the cost of labor escalating, we have determined it is cheaper to add a GPS clock at each of the elelctrical rooms in the plant than to pull, terminate, and test the IRIG Coax all over the plant.
DNP does not work well for synchronizing event recorder clocks in protective relays. It is better than nothing but gives errors when comparing event reports. During a plant trip the communications links can get busy and add additional delay errors to event records. What's the hold saying:
"A man with two watches never knows what time it is."
RE: Time synchronisation of IEDs
When you need tighter synchronicity, IRIG is the way to go.
And seriously, the cost of IRIG receivers is dropping fast, so they're not a major installation cost any more, more like a rounding error in the cost of a decent substation.
old field guy
RE: Time synchronisation of IEDs
RE: Time synchronisation of IEDs
RE: Time synchronisation of IEDs
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(2B)+(2B)' ?
RE: Time synchronisation of IEDs
RE: Time synchronisation of IEDs
Good to know. That way I won't duck for cover if someone tells me there's an IED when touring a substation.
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(2B)+(2B)' ?