I am talking about a oil producing facility. I have installed a 6.6 kV junction box. As the name suggests it is a junction. So two cables are terminated to the junction box. The junction box is classified as protection Ex "e" enclosure.
The strange thing happening in this case is hydrogen gas...
The same hydrogen generation theory holds good for power cables also.
In our case aluminum is not used. These are GI armoured cables. The galvanized (GI) armours are having the zinc coating. The hydrogen generation theory for the reaction of zinc with sea water is also now a known fact.
The...
This submarine cable is a composite cable consisting of power conductors as well as Fiber Optic (FO) section. The 96 fibers are split equally between electrical and Controls & Instrumentation application. So the FO portion is separated out in the JB and then divided equally to electrical and...
FreddyNurk,
You are contributing a lot on the subject. Thanks for that.
As you rightly said, ventilation brings its own set of problems.
I have an idea. Why not do some filling inside the box. This would reduce the void space inside the JB. So there may not be a build up of H2.
But please...
The facility might have invested few tens (if not hundreds) of million dollars for the cable procurement and installation of these submarine cables. These cable are procured from one of the best know manufacturer. Replacing the submarine cable installation of totaling about 75 kilometres at this...
FreddyNurk has precisely answered ppedUK’s query.
The JB was meant for the installation at Oil Producing platform. So Hydrogen gas from the facility is not expected to be present.
This is an unusual situation. It is an established fact that the H2 gas is entering from the cable. In one of the...
General:
Thanks for all the valuable inputs from the distinguished panelists. Your views have reaffirmed my own understandings and enhanced the thought process.
To give a perspective, I am elaborating the background and the intent as below:
6.6kV power junction boxes installed at offshore...
7anoter4, davidbeach - Thanks for your inputs.
My query here is more to do with the Ingress Protection (IP). In terms of IP classification, whether the enclosure IP 66 is expected to be air tight?
Power system stability is a recognized terminology in the context of power system analysis. Where as power system resilience is not a recognized terminology in the context of power system analysis.
In the IEC world "power system resilience" is not a commonly dealt subject subject. To me it...
Considering a lead time of about 6 to 9 months for the 230 kV XLPE cable with customized specification is reasonable. However, now considering the Covid-19 scenario, the variation of lead time between the vendors could be wide, depending on the lock down restrictions in the respective countries.
The question here is about Ingress Protection(IP) Level as per IEC standard 60529. As per this standard, I would like to know, whether the IP-66 enclosure is air tight?
or
Air tight IP-66 enclosure is permitted for the Hazardous area application?
I have a 6.6 kV power junction box with below...
FreddyNurk (Electrical),
Thanks for your valuable feedback (positive). Yes, it is Rogowski coil.
I don't know whether any one has any negative feedback on the Rogowski coil based bus bar differential protection.
One of the reputed European vendor is proposing sensor type CTs for the bus bar differential protection in their new switchboard. This is the main switchboard in the power plant. However my end user has some reservations on using sensor type CTs, as these are not proven. Since this is the heart...
Kiribanda,
There is no such continuous over voltage on the bus. But the any disturbances on the power system may yield relatively higher degree of voltage disturbances.
Otherwise I am not finding any technical reason to select the higher voltage grade cables. But in reality it has been the...
Additional information/clarifications:
The system is Low Resistance (LR) grounded. 11 kV system neutral earthed to limit the current to 200A.
This is an offshore oil processing platform. Like a marine environment. Power system is an island system and the power generation is at 11 kV. These...
I have an 11 KV offshore power distribution system. This system has only onsite power generation and operating in Island mode. I am replacing the old 11 kV cables. Problem is that we do not have the data sheet of old cables. Now we are facing problem in in selecting the cable voltage grade...
Thanks for all the participants. Raghunath's response specifically stands out.
The terms like low magnetizing current CT and low leakage reactance CT were the terms were little intriguing for me for long time. Now the application aspect of this is understood. That too after 30 years of of...
In one of the 11kV system earthing study the final recommendation is to use the low Resistance earthing to limit the earth fault current to about 125A. In the meantime the study has also suggested to use the low magnetizing current CTs for the earth fault detection.
When specifying a CT with...
