Line Differential Protection Via Ethernet based Network 1

[anggapra]

Hi All,

There are GE L90 Line Differential relays communicating via TDM-based network installed on our field.
Due to network infrastructure upgrade, our ICT team want to replace the TDM-base network with Ethernet based network.

Is it possible for line differential relay communicating via Ethernet based network to transport the differential current and timing information?

Thanks,
Angga

 

[davidbeach]

I don't know about the L90 specifically, but line differential over Ethernet is possible. I would seriously try to avoid it for cybersecurity reasons. Protection comms decisions should be being made by protection folks, not by know-nothings on the IT side of things. They going to buy you all new relays?

I’ll see your silver lining and raise you two black clouds. - Protection Operations

 

[stevenal]

SEL Paper

 

[anggapra]

thanks david and stevenal, i've read some literatures discussing ethernet based network for line differential protection before, but I'm not really sure it's been applied in actual installation

 

[FacEngrPE]

This is not consumer or even commercial Ethernet.

"packet-based technologies based on multiprotocol label switching (MPLS) or Carrier Ethernet"

RFC 3931 - Multiprotocol Label Switching Architecture I suspect that a successful implementation would require careful design, extended parallel operation, a lot of fine tuning, and the protection engineer being the person to rule on the result being fit to task.

And of course putting protection data on a shared pipe requires significant ongoing cybersecurity efforts.

 

[stevenal]

This paper provides a wealth of performance data taken from
Central Lincoln PUD in-service protection systems running line
current differential schemes over a converged information
technology/operational technology (IT/OT) packet network.

Yes, the system described is in-service.

 

[davidbeach]

I'm sorry to hear that...

I may not have much choice about handing off a serial 87L channel to be packetized and sent over an MPLS network, but I'm in no hurry what so ever to have any communication aided protection (in my case either Mirrored Bits or 311L/411L 87L) leave the relay in a routable protocol. There are definite cyber security reasons to stay away from that, I also don't want the planners to ever have any inclination of the number of terminals supposedly possible doing 411L 87L over Ethernet.

I’ll see your silver lining and raise you two black clouds. - Protection Operations

 

[cranky108]

Real easy, don't allow three terminal lines. And because POTT seems to be faster than the DD in typical 87L channels, we don't use it except on short lines with direct fiber.

 

[stevenal]

Did you read the bios? Cybersecurity was not the subject of the paper, but would someone with those credentials not consider it?