Carrier current protection 1

[Mlmlzx]

Dear sirs,

I was doing relay works in local control and relay panel room when the relay engineers told me that carrier current protection is used for distance protection for 220 kV.

Bus there is no line trap, and we are using optical fiber (not plcc). Is this feasible?

Regards,

 

[davidbeach]

Names tend to stick around through multiple technology changes.

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

 

[RRaghunath]

Yes, it is common these days to use FO communication channels for Distance protection communication at either end of the transmission line. The numerical relays available in the market can directly accept a Optic fiber. One channel can be direct and the second channel through Multiplexor to have redundancy in communication.
Apart, using FO communication it is also a practice to provide Line Current Differential protection as Main-1 protection (with Distance as Main-2 protection).

 

[thermionic1]

In our system, where PLC was not available or practical, we would use Audio Tone transceivers over a leased TelCo line. The TelCo's no longer wanted to support a direct point to point copper line and were hitting us with $1500/mo/line fees.

We built a FO network on the system. During some of the early cut overs from the Audio Tone system, we used a module on the Sonet hardware that allowed us to directly plug an RJ-11 (4 wire) connection in. This required no changes for the relays or existing transceivers other than a new RJ-11 cable to the relay panel. We could cut the new communications system over from leased line to Sonet in about an hour and a little pre work.

Not everything goes smoothly. I remember doing a line relay panel upgrade that was to include new OPGW (FO) cable to be installed on the transmission tower static lines. There was a freak spring day and high winds caused the helicopter, the pilot and a few linemen to go down and not return.