Looped Distrbution circuits

[mbrooke]

Want some guidance and opinions on any one of these... real world experience also welcome.


1. What are the advantages of looping distribution feeders from other substations instead of neighboring feeders originating from the same substation? Assume ties are run normally open.


2. Advantages/disadvantages of looping with feeders from other substations and operating all reclosers (tie reclosers) in a normally closed state.

Here is an example single line of what I have in mind:

https://youtu.be/WIFn_sI7jPE?t=58


Open to any and all discussion. I can give more detail if required or curious.

 

[Tony S]

Over here both LV and MV systems are usually run with a normally open point. In the event of a cable fault the open point can be moved and supplies restored. It can lead to a complicated system.

 

[mbrooke]

Over here both LV and MV systems are usually run with a normally open point. In the event of a cable fault the open point can be moved and supplies restored. It can lead to a complicated system.

I like complicated! Is all this done manually or automated?

 

[Tony S]

Both, the supply companies are gradually upgrading city areas to use telemetry for remote monitoring and switching. The rest will take time.

Believe me paralleling two transformers with solid links in an underground LV link box is a bottom clinching moment.

 

[mbrooke]

Both, the supply companies are gradually upgrading city areas to use telemetry for remote monitoring and switching. The rest will take time.

Makes sense- as is typically the case.

Believe me paralleling two transformers with solid links in an underground LV link box is a bottom clinching moment.

Yup, often better to just loop things at the MV level. Though places like cities where you have networks it does get interesting.


But in any case be happy you are dealing with simple loops, you could have this instead


https://ady1607.files.wordpress.com/2014/05/sop-gi-kbl-2014.jpg

 

[mbrooke]

Both, the supply companies are gradually upgrading city areas to use telemetry for remote monitoring and switching. The rest will take time.

Believe me paralleling two transformers with solid links in an underground LV link box is a bottom clinching moment.

Tony, I found this:


https://pure.tue.nl/ws/files/22468884/20160523_Grond.pdf

A bit technical but through out gives the general structure of the Euro ring. Do you have any idea about length, loading and MVA trafo size in the DNO's system?

 

[Tony S]

http://innovation.ukpowernetworks.c...projects/Flexible-Urban-Networks-Low-Voltage/

 

[mbrooke]

http://innovation.ukpowernetworks.c...projects/Flexible-Urban-Networks-Low-Voltage/

These are by far the most helpful. Thank you yet again.

 

[Tony S]

Did you have a look at FUN distribution systems

Just noticed, the project has been closed down. A shame as it showed a lot of promise.

 

[mbrooke]

Did you have a look at FUN distribution systems

Just noticed, the project has been closed down. A shame as it showed a lot of promise.

FUN? No. Did not see that one.

 

[beanland]

Radial vs. Looped

Radial vs. Looped

Want some guidance and opinions on any one of these... real world experience also welcome.
1. What are the advantages of looping distribution feeders from other substations instead of neighboring feeders originating from the same substation? Assume ties are run normally open.
2. Advantages/disadvantages of looping with feeders from other substations and operating all reclosers (tie reclosers) in a normally closed state.

Radial lines are simple, overcurrent devices are in series, protection can be fuses. System cost is kept lower. The disadvantage is that faults can create large outages.

Looped lines, even a simple loop, increase fault current, lower voltage drop, but require automated switching devices for restoration. The advantage is higher reliability but at much higher cost and complexity. You have to be willing to pay higher rates for higher reliability.

 

[mbrooke]

Radial lines are simple, overcurrent devices are in series, protection can be fuses. System cost is kept lower. The disadvantage is that faults can create large outages.

Same can be done with looped circuits, taps can still be fused.

Looped lines, even a simple loop, increase fault current, lower voltage drop, but require automated switching devices for restoration. The advantage is higher reliability but at much higher cost and complexity. You have to be willing to pay higher rates for higher reliability.

True if the tie point is run normally closed.

 

[Tony S]

FUN? No. Did not see that one.

http://innovation.ukpowernetworks.c...Benefit+Analysis+(SDRC+9.6)+December+2016.pdf

 

[mbrooke]

http://innovation.ukpowernetworks.c...Benefit+Analysis+(SDRC+9.6)+December+2016.pdf

Thank you