High Voltage DC Safety Requirements 1

[kayakdave]

Greetings All,

I am working with a large company that is tasked with doing long term testing of electric vehicle propulsion systems. They are trying to find out what the safety requirements are for working with High Voltage DC. This is an area I'm not familiar with and was hoping someone here could point me in the right direction.

Thank you,
Dave

 

[DTR2011]

Please be more specific as to your location (relevant codes) and voltage you are working with. An example of the application would also help.

 

[kayakdave]

Thanks smallgreek,

I asked the client for more information and will post it as soon as they get back to me.

Cheers,
Dave

 

[kayakdave]

Here is some additional information on their DC Load. Thank you in advance for any help you can provide.

Location: Winston Salem NC
Voltages: 600 VDC at currents over 2000 amps and 1200 VDC at currents over 200 amps.
Laboratory testing of products. Both short duration (minute or less) and long duration (several days) testing at high power. Some testing in controlled environments (temperature, humidity, vibration, etc...).

 

[dpc]

I would start with NFPA 70E-2012, Electrical Safety in the Workplace

This will be fairly generic, but there are now specific requirements for arc-flash protection on dc systems. Also, many of the general safety requirements apply to both ac and dc systems.

There may be some additional references in NFPA 70E that lead you to additional standards and guides.

 

[kayakdave]

Thanks dpc, I will take a look at that section.

Cheers,
Dave

 

[Skythian]

please check the article On the Performance of Arc Flash Analysis in DC Power Systems

 

[Skythian]

DCAFA V2.0 software is applicable for systems with voltages in the range of 125 to 2000VDC and available short circuit currents from 1 to 50kA.

 

[ScottyUK]

Do you work for the software company by any chance? If you do then it is good manners to disclose it.

The article was quite interesting. I'm pleased that analysis methods are being developed so that very high energy DC systems can be assessed in a reasonably scientific manner. I'm not sure how the analysis deals with large inductive energy stores (such as rotor field windings) where the source voltage is variable, but I guess the incident energy is relatively low because the inductor behaves as a current source and the fault current doesn't rise during the fault. It would be useful to understand how well the analysis can deal with active sources such as controlled rectifiers when an arcing fault occurs on the DC side. The majority of very high energy DC systems are likely to be rectifier-based rather than battery sources, and the simple model proposed in Equation 1 probably isn't going to be sufficiently accurate for these sources.

Thanks for the link.

 

[Skythian]

I am very glad you've liked the article and link to DCAFA V5.0. Indeed, I am the software developer and I'm looking forward to seeing how it is received. Equation 1 applies directly to any linear circuit with voltage or current source. Current sources would require simple source transformation by transforming a current into a voltage source prior to applying the Equation 1. The Equation 1 could also be applied to rectifier-based sources as long the source load line can be approximated by a straight line. Otherwise, the rectifier-based source load line should be used instead of the Equation 1.

Thank you for your valuable feedback.