At a local industrial site they have a set of 30 year old 115 kV single conductor cables terminated using potheads. The shields at the source ends appear to be terminated to ground through a carbon air gap mounted on the cable support structures (see attached photos). Can anyone confirm that the...
In my opinion armoured cable is allowed in conduit as per Rule 12-902 (2) as long as fill ratio and pulling tensions are not exceeded. Multiconductor power cables larger than #1/0 installed according to Diagram B4-4 need to follow the ampacity tables D14 A and B. Rule 4-004 (1)(d) and (2)(d)...
Thank you. My specific situation is a little different than a standard grid connected power generator in that the generator is a 4160 Volt unit embedded in an industrial distribution system where the system is being upgraded to 13.8 kV and a tie transformer is being considered between the...
Is a generator step up transformer typically specified for hydroelectric generators in the 10 MVA range or is a standard distribution transformer typically applied? I understand that GSU transformers have different specifications for power flow in the reverse direction for large generators but I...
I am struggling on how to address system ground fault currents on load substations connected to 3-wire 44 kV sub-transmission lines with no ground return path (no neutral or overhead ground wire). The utility quotes a zero sequence ground fault current at a point on the line however I am...
We believe it to be an alignment issue from installation and/or a soft foot on the generator. The engine/generator sets are CAT supplied in standard winterized enclosures with substantial mounting rails and foundations that meet or exceed the specifications in CAT's mounting guide and there does...
CAT done an assessment and haven't come up with an specific explanation either. Apparently they haven't seen this previously. I am thinking mechanical as well but I still haven't ruled out something related to transient oscillations between synchronized machines, possibly due to starting of...
Also the units are installed in vendor supplied modular generator enclosures with generator mounting rails and linear spring vibration isolators. They have an 1850 ekw prime rating.
The site is in Northern Ontario and presumably the installation work was done by qualified tradesmen per certified installation drawings. The mechanical inspection did not uncover anything obvious including a review of the foundation and alignment procedures. This is installed at surface at a...
I have attached a photo of a typical crack. They are 3516C machines and were commissioned in 2010 but I don't have specific information on hours or number of starts. They run an off-grid system so would cycle as needed based on a set priority. The crack appears in the same place on all machines...
We are working on a situation at a remote mine site where four 4160 Volt, 2 MW Caterpillar diesel generators are operated in parallel in an off-grid configuration to provide power for the site. Over the span of many months, several of the generators have been experiencing cracking of the stator...
Thank you, we are presently modeling the site using SES software. I was curious to see if installing a buried ground conductor around each array support was commonplace or just around the overall perimeter of the site. The SES software should uncover any hazards but the extra buried copper...
I am working on completing a ground potential rise and grounding study for a large 10 MW ground mounted PV installation. The site will be interconnected to the utility grid via a 44/12.5kV substation with the substation ground interconnected with the PV module grounding system. The 44kV system...
After further investigation it appears that several factors were at play here. Firstly, the reactors only appear to have been designed to rated current at nominal voltage, as there is no maximum operating current or voltage listed on the nameplate. Secondly, the units are 115 deg C rise units...
