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 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...
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...
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...
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...
We have some 25 kVA, 110V AC UPS in the offshore oil platforms. It is installed in the air conditioned room. These UPS are only just six (6) years old. Vendor has suggested that we should replace the UPS capacitors, for the better reliability.
I wonder, how frequently the UPS capacitors shall...
One of the remote oil fields we have many Chemical Injection (CI) skids installed at various locations. These CI skids are installed recently (between 1 to 3 years old). Each CI Skid is having single pump and intended to be operated continuously.
The pumps are driven by 24V DC Permanent magnet...
The motor in question is 11kV, 3,300 kW Ex”d” 3-phase, squirrel cage induction motor. It has stator winding RTDs. Two RTDs per phase, thus total six (6) RTDs. Now one of the RTDs (say RTD#4) is found to be faulty. Presently the RTDs are connected to RTD module of the motor protection relay. This...
I have an Emergency Diesel Generator (EDG) rated 640 kW rating. It has an alternator rated 800 kVA, 415 V. Using soft starter, we have started a motor of 260 kW rating. When attempting to start the motor EDG tripped with many alarms/indications. One of the indication is the diode failure...
One of the motor winding temperature RTD Loop is malfunctioning and tripping. The motor is 11kV, 3300 kW, fed from 11kV switchboard.
Historically, two (2) RTDs (one from Y-phase and other from B-phase) of the same motor are out of service since commissioning. The present problem is with the...
One of the 11 kV, 3000 kW, 2900 rpm motor was recently overhauled.
When the motor was sent back to site, they have conducted the motor solo run. The magnetic center of the rotor was found to be drifted.
Total axial free float of the motor is 13 mm. The magnetic center is expected to be at...
One of the 11kV, 3000kW motor was recently overhauled in an outside workshop which is not part of the plant. The workshop did not have the testing at 11kV. Hence they have tested the motor at a reduced voltage level of 3.3kV. The testing was found OK.
When the motor was sent to site, they...
We have forty (40) year old Frame-5 gas turbine generator (GTG) units in our site and still operating. As the units are old, failure rates are slowly creeping up. At this stage the original spares are exhausted in our stores. However, sourcing these spares have become very difficult. Either the...
We are procuring a small chemical injection skid which has a chemical injection pump. The motor rating of the pump is 0.18 kW. The skid supplier has offered the motor having single phase. My client wants a three phase motor. He says that it is the industry standard.
In my opinion, such a low...
Difference between DLA test and tan delta test for HV motor
We are intending to perform condition assessment for a 11 kV, 3000 kW motor. Some one has specified two tests, namely
a) Dielectric Loss Angle Test (DLA test)
b) tan delta test
As I understand, functionally these tests are same...
Good day!
I am presently entrusted with a job of reconditioning a 3MW, 11kV Motor. The motor is almost a quarter century old, commissioned in the year 1992. From the beginning this motor had lot of problem, but continues to run all these years with routine maintenance. Now the facility owners...
This is regarding the requirement of fire fighting system for one of the critical switchgear room in the offshore platform. Presently it has active fire fighting system. This is an existing switchgear room having this fire fighting (FF) system from the beginning.
As the existing FF is now...
I have three sections of underground cables 3C x 95mm2 of say 3.5 kM length each. From the source at 3.5km distance it is terminated in a junction box at one location (say Location-1). It is jumpered to an identical junction box installed adjacent to this JB.
From Location-1 second JB the...
Is it mandatory to provide boot for 6.6kV (HV) terminals to certify the enclosure as Ex ‘e’?
Or
the junction box containing bare (exposed) live terminals inside the junction box can be certified for use as Ex ’e’ enclosure?
My concern is some static discharge during the switching of...
