Control Cables for Upstream Substation Signals & Tripping

[SK07]

I have been regularly using multiple core 2.5 sq.mm XLPE/LC/PVC/SWA/PVC Control cable for signals & tripping between Upstream and downstream Substation with distance upto 5-6 Kms.
The signals are as,
1. Solkar Pilot Wire for Differential Protection Relay - ANSI NO. 87
2. Inter Trip Send - ANSI NO. 94
3. Inter Trip Receive - ANSI No. 85
4. Upstream Earth Switch Inter lock
5. Upstream Circuit Breaker ON Status
6. Downstream Circuit Breaker OFF Status

However, in one of my recent Projects the distance between Upstream and Downstream Substation is close to 11 Kms.

My question is - Can I still use the same Control Cable ''multiple core 2.5 sq.mm XLPE/LC/PVC/SWA/PVC''.

 

[ScottyUK]

Marmite - is the GCM05 still in production? It has been de-listed on Alstom and Schneider's websites and I'm not sure which business unit got that relay after the Areva breakup. So far I haven't needed to replace one but it would be useful to know.

 

[Marmite]

You might be right Scotty. I had a look at Alstom and Schneider websites but almost lost the will to live trying to find anything useful.
I have an old Areva price guide from 2007 which lists them, and I had a recollection that we were using them in the DNO I worked for in the UK upto 2012, but I may be mistaken. Siemens and others still do surge proof DC intertripping relays though.

Regards
Marmite

 

[SK07]

Thanks everyone for your time and inputs.

I have obtained information from Siemens Catalogue that is quite useful,

Solkor R & Solkor Rf Pilot Wire Differential Protection Relay (ANSI NO. 87) is suitable for application on a single pair of pilots with loop resistance up to 2000ohms to protect 2 ended feeder circuits up to 20km in length. Two compatible relays are used as a pair with one relay connected to current transformers at each end of the feeder respectively. The Solkor R/Rf relays do not require an auxiliary DC supply.

The Solkor R/Rf relay has an insulation level of 5kV between pilot connections and the local ground to withstand voltages induced on the pilot cable due to coupling with the fault current and to withstand differential ground voltages caused by the flow of fault current. Experience has shown that 5kV insulation is usually adequate for most distribution feeders.

For higher voltage systems where feeders may be longer and fault levels higher, an additional external isolation transformer is available for use with the relay in Rf mode to increase the voltage withstand to 15kV.

 

[karls2]

It's also a good idea to have a good distance between control and power cables, I have already see all in the same pipe, and it can generate some issues...