In our plant we have a 15 Mega watt compressor connected with an XLPE cable through a switchgear.

We faced during start up (1200Amp) of the compressor a high temperature of the cable and especially in one phase. After High voltage test and insulation test the cable was very good. my question is why this high temperature in the phase? and what can be the causes.

thanks

 

Can you touch the cable without being burned? if so, it is not overheating.

What size is your cable?

If it is only hot on one phase, it may indicate that phase has more current than the other two phases, which is not all that easy to do if it is hooked up correctly.

--
Bob

 

Henny... how about some detail, like:

o Synchronous or asynchronous motor?

o Voltage?

o Starting method, DOL, reduced voltage, etc?

o Single-core, 3-core, 3-1/2 core?

o Cable mmq size?

o Number of conductors per phase?

o Current in each phase?

o Distance between switchgear and motor?

o Amperes per phase?

o How was temperature measurement determined?

o Starting time, from breaker-closing to full-speed?

Regards, Phil Corso

 

>Henny... how about some detail, like:

Is there 3 different cable for 3 different phase...??
How many condustor is there in one cable...??
is it single core cable...??

 

Dears,

Synchronous motor
25KV
Starting method Y/delta
3 cores
size of cable is OK
6 conductors per phase
current in each phase = 700Amp
Temp measured by camera / infra

F.Y.I : the temperature was high = 140deg for only one phase but only in the area of the switchgear around 20M, if we go close to the breaker the temp will increase more, i want to know if the magnetic field can be the cause or the tightnessor something else.

Thanks

 

Henny... several more questions:

1) Is this a commissioning problem or a new problem in an existing facility?

2) Is the high-current present: a) during acceleration; b) just after application of DC to rotor; or c) while carrying a load?

3) Can you send pictures showing how the conductors are configured in the area where temperature is highest?

4) Also pictures showing how the circuit-breaker cubicle bus-stabs are arranged in the Wye and Delta contactor cubicles?

5) Also pictures showing how the six conductors are configured where how they exit the switchgear enclosure(s)?

6) Motor PF rating?

Regards, Phil Corso (cepsicon[at]aol[dot]com)

 

Henny... question 5) of my earlier post should have read six conductors per phase...

Phil

 

Hi,

This problem occurred due to unbalancing of load. check out the load first

also check the impedance of cable and motor both.

thanks

 

Bad contacts at the breaker for that particular phase, too much bending/twisting stress on that particular set of cables?

Regards,

Tomy Zacharia

 

Seem to me like you have a bad connection at the switchgear on one phase.

William (Bill) L. Mostia, Jr. PE
Sr. Consultant
SIS-TECH Solutions, LP
Any information is provided on Caveat Emptor basis.

 

Henny... also look at:

http://control.com/thread/1285417132

Phil Corso

 

Henny... If you provide the data requested, I can confirm my thesis about the cause! Conversely, if you now know what the cause is, please tell us!

Phil Corso

 

Dear all,

Thanks so much for the help, it was a bad connection of the cable in the switchgear. the switchgear it self was broken. we already make maintenance for the switchgear and every things is OK.

Thank you & best regards

HENNY