Recent content by 144x

Is there an example or guide or standard that has the formula that you can guide me to?

Hi, If a metallic bar is continuously heated by a heater, how the final temperature of the metallic bar can be calculated? I'm looking for some formula's to do manual calculations without resorting to sophisticated softwares. Metallic bar is not enclosed and on one side is in touch with a...

Like the attached sketch. Instead of two panels, both incoming and outgoing cables terminate in the same panel. have you seen such a case?

Hi, Imagine an MV switchgear is going to bypass an isolated gap in a busbar/conductor, etc. I want to know if anyone has seen an MV cubicle design where both incoming and outgoing cables to both sides of the gap terminate in the same MV cubicle. Is that at all possible? is there any standard...

how much do you need it to be? what problem has it caused?

you are comparing CT's made and measured according to two different standards. one BS and the other IEC. X is the old standard. I think you better stick with the new one PX.

if you have access to AS/NZS 3008.1.2 read it. if not you can read this https://www.nexans.co.nz/NewZealand/2013/Power%20Cable%20Catalogue%20Full%20version%202012.pdf which basically explains the assumptions in that standard. if not this page also explains how to include the PF in your tabulated...

The "I" is different in those formulas

Here is a case where using 4 pole breaker may prevent mal-tripping in other feedershttp://files.engineering.com/getfile.aspx?folder=165e8c38-a77b-4e9a-9244-158dcce1e72c&file=LV_switchgear.pdf

I don't think you will find any standard that specifically mentions that signal. these are developed based on years of experience, trial and error and safe operation of the switchgear and is different for each industry. you should have years of experience to understand the need for the signal...

you can find the answer to your questions in the following references: 1- TECHNICAL BROCHURE Title: Protection, Monitoring and Control of Shunt Reactors-CIGRE WG B5.37 2- C37.109-2006 - IEEE Guide for the Protection of Shunt Reactors 3- IEEE Guide for Automatic Reclosing of Circuit Breakers...

Thank you prc, if there is any limitation or requirement to be considered on the design of inverter transformers arising from irradiation variable or cyclic heating and cooling shouldn't these be mirrored or considered on the collector transformers as well ?

thanks prc, is "IEEE C57.159-2016 – IEEE Guide on Transformers for Application in Distributed Photovoltaic (DPV) Power Generation Systems" is applicable for such large transformers also? I do not have the standard though.

Thanks waross, let's assume there is no voltage drop as it is injecting power to the grid.

Hi, my question is what happens if a power transformer is loaded most of the time close to half its full capacity and only for a very short period close to its full capacity. this happens in a design where a solar farm is going to be connected to grid (230 kV). should any special design be...