Test Van:How to Find the cable fault location Part 3-3

This's the last part of this series.In this part, we learn How to use ARM Full Feature and SWG (Surging Mode).Plz Note That: If you Have Any Question, Add It, And Mr.Adolffs Will Answer It.

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[marian80366]

How do I find a defect that is about 100ohm with pingpoint method but all I hear sound length of cable?

[Antiinequity]

@marian80366

PART 1-2

well,it depends on the distance .so if the cable is short ,u should walk all the distance and i believe u'll hear a litte click wich is actually the fault.cuz there is a small gab wich makes a small spark between the chosen faces. so u won't hear a real fault sound.

But if the distance is long,then u have two ways to locating:

[Antiinequity]

@marian80366

PART 2-2

1.must knw the resistance to all other faces.then use the highest one.for example,100ohm and 1k ohm and 13 kohm

so, u'll use 13kohms and trust me it works.

2.using Audio Frequency Generator in case there is one face(at least) has 0 ohm resistance.

wish all the good for u ^^

[hayatmk]

how we locate fault in 5 KV 3 core xlpe insulation power cable,found all three phases shorted and ground, insulation resistance for all three phases 0 ohms and 0 volts.Plz advise what method for locating this type of cable fault.

[Antiinequity]

@hayatmk Part 2-2

and this has happened to me "before two weeks"where the capacitor explosion inside surge device

The solution is in three important steps First:connecting cables(as you do always)without any change(face + ground)Second

Put a plate of plastic or any insulating material between faces (on the plug to isolate the arc return (if happened) from the second face

Third: start working on the cable as usual without any change but the important point is the second step All the best for you

[MyUnderSlungLink]

@hayatmk Are you sure its exactly 0 ohms? Thats a pretty rare fault to happen on a network. But you can still find it. When you say 3 phase to ground i assume you mean the copper screen. So in that case you can even use cable tracing gear to locate where the fault is. or signal injection. And walk the length of the cable until the signal stops. Because you can make it travell down the 3 cores and return via the sheath. So the signal will not go further than the fault.

[Antiinequity]

@MyUnderSlungLink you have agood experience,man ^.^ you are right,it's very rare ((0 ohm)) but i think it's not because here in Saudi Arabia i see many people say:it's 0 ohms but in fact it's less than 1 M ohms(maybe 10 Kohms) then,it's shown near than 0 ohms in the Megger(analog not digital) but believe me, it's not 0 ohms so i told him go ahead its OK because I know it's not 0 ohms. ^_^ And welcome to the Club

[Harwkins39]

I'm curious how you inject your test signals. Is there HV on the cables at the time? Capacitive or inductive coupling?

[marian80366]

correct method to use for defects with low-impedance pingpoint?



[marian80366]

este corect sa folosesc metoda pingpoint pentru defecte cu impedanta mica?

[Antiinequity]

@hayatmk .Part 1-2 There are no any differences between this case and the ordinary cases, which sometimes,one core is damaged or burned splice

But the problem is complete here in as short between three phases and the ground.

It doesn't matter how many faces, but the important thing is that tow faces are short, so if you connect face and the ground, the risk of back discharge to the device is too large (because faces are connected with each other with the ground)