Phasing Out Procedure

Normally phasing is checked before the switchgear or VCB is closed because if the phasing is wrong you quickly know about it.

in such case using phase comparator at vpis.

I have never used one of these (or had the need to).

If you do not have connected protection relays (or similar) that can sense the correct phasing can you not manually check the phasing before the switchgear or VCB is closed onto an existing live ring main circuit? Most switchgear I have worked with has at least test points for checking phasing and phase rotation while the switch is open.

What country is this in, and what 11kV distribution switchgear are you using?

Sorry, but what do cvt & vpis stand for?

Merlin gerin Genie vcb

I am not talking about dead phasing. is dead phasing enough. WE ARE doing 11 kv live phasin before closing 11 kv ring ,

now in MG genie EVO OR siemens NXPLUC C WE ARE FACING THIS PROBLEM AS THESE ARE FIXED TYPE VCB.

You are facing this problem because you took on a job that you are not adequately trained to do. Contact the manufacturer or the engineer that designed that configuration.

In our 11 KV Distribution ring network, whenever a ring is overloaded we transfer loads to another ring. To ensure the phase sequence to be same, at the cable cut point, both the cables to be joined will be stripped and bare conductors will be kept ready for live phasing. Now the 11 KV supply will be fed from both ends upto the cut points. Then the Operation team, use their live phasing kit and checks 3 phase conductors of a cable with other cable's 3 conductors with each other to ensure correct phasing.
Is there any other method to check the phase sequence because it is very dangerous to work?

Why aren't you checking this by dead phasing, why must it be live. Live phasing could be done at circuit spouts if you have withdrawable Circuit Breakers

The phasing can be checked dead and therfore removing the risk of working with live HV conductors.

But how to ensure the phase sequence in dead circuit...because the cables to be joined is from different feeders.....
we transfer the load without causing interruption to any customers. So live phasing is only choice.
If we want to transfer a 11/0.4 kV station (SS1)from a ring1 to ring 2...
1.First we release the cable between the Ring 1 and one side of SS1...still maintaining the supply to SS1...(paralleling the ring)
2.then in ring 2 the cable where SS1 need to transferred will be released.
3.Now new cable will be layed between ring 2 to SS1 and at cut point live phasing will be given and then it will be joined....
4.Now other side SS1 will be released (no interruption) and another cable is layed connecting ring 2 and again live phasing is carried out and cable will be joined together.. now the load is transferred to ring 2...
5.Now the Ring 1 is again joined together after live phasing

For Live phasing we use live phase stick.....we ensure safe work environment and practice once at dead condition..then the live phasing will be done by charging the cables upto cut point...What other methods we can use to make this work less complicated?

I understand that your concern is that the phase rotation on ring 1 circuit is the same as ring 2 circuit and that at some point entails a live test.

If you can get to the cable terminations within the ring main units then you should be able to identify the connections to the cable and that would mean you would only need to carry out one live test as the phase rotation would be the same on both sides of the ring main unit.

I think the first thing I would do is to check with the manufacturer of the ring main unit and see if they supply a phase comparator unit for their switchgear as ABB do with their Safelink units.

ABB Safelink

If not, you might be able to make something up yourselves that would fit into your switchgear.

The only other thing I can think of, if you have to do this at the live connection ends, is temporarily reducing protection settings on the cable feeders if you can, whilst the phasing is being carried out. You could perhaps also look at a temporary arc protection unit but that is going to depend upon how close your ring main units are to the point of work and if you can get trip wires into them.

Do you make the cable off into some type of an enclosure or frame with spouts in it and then do the test from those, I guess that would be safer than phasing direct onto the cable ends as it sounds like you are doing now, but I suppose that is going to depend upon how much cable you have to play with.

After that it is appropriate training, equipment, fire and arc resistant PPE and procedures.

Ultimately it is going to depend upon a risk assessment from yourselves as you know all the details about the job and I am only summising.

Phasing and phase rotation are differant and should not be confused.
Whatever type of switchgear is used there is normaly some form of cable access. If a dead check phase is done on each cable before cutting the rotation can be established. The appropriate connections can then be made and checked by dead checks.

Live phasing is a luxury that is still required in the event for 100% proving of correct phasing between 2 sources. However it is done after many preliminary checks had been done and it can only be carried out with proper equipment under safe operating environment,

During Load Transfer (without causing interruption) atleast one live phasing is given to ensure the correct phasing....not thrice as i explained before.

We use Live phasing stick to compare the phases..but i consider it as a high risk job..is there any other safe method to identify the correct phasing?....without causing interruption.

I was wondering if you ever found out how to do this? I am in a similar position. What is the voltage at the test ports. Are you measuring voltage or phase angle? What is the tolerable range for voltage if that is what you are measuring? You can check for correct wiring between vpis and cvts by checking phasing between two panels connected to the same bus.