[SystemSafety] Solar Storms and Charging Procedures for Electric Cars

Martyn Thomas martyn at thomas-associates.co.uk
Wed Apr 10 16:30:03 CEST 2013


On 10/04/2013 10:57, Peter Bernard Ladkin wrote:
> Martyn,
>
> On 4/7/13 7:14 PM, Martyn Thomas wrote:
>> I assume you have seen
>> http://raeng.org.uk/news/publications/list/reports/Space_Weather_Summary_Report.PDF 
>>
>>
>> Which of the phenomena is seen as creating a hazard for EV charging?
>
> I think Section 9 is relevant: Avionics and Ground Systems. The report 
> sees solar energetic particles (SEPs) as the main problem for ground 
> electronics, and not geomagnetically-induced currents (GICs).
>
> However, I wouldn't know whether GICs would be a concern with an 
> active charging system. Can anyone help?

My understanding is that you need a long run of conductor before GIC's 
become significant, except around transformers that have a major 
magnetic field of their own that interacts with the earth's magnetic field.

But I'm no expert.


>
> I do know somewhat more about SEPs, since I looked quite hard at what 
> was known about cosmic rays, about a decade ago, and talked to the 
> particle physicists in Bielefeld about them, during the course of 
> trying to figure out what was known about single-event upsets (SEUs) 
> in electronics, and to what level of radiation, and what kind, people 
> and electronics in commercial aircraft at cruise altitudes on various 
> routes might be subject. There seemed to me a lot of mantras floating 
> around from various quasi-authoritative sources but talking to the 
> particle physicists I had many responses of the sort "how do they 
> (think they) know that? We don't!"
>
> The SEP increase raises the question of an increase in quantity, and 
> diversity, of SEUs, since the spectrum of SEPs in a solar storm is not 
> well understood, according to the report. Since SEUs disrupt the logic 
> of the electronic circuitry, it seems to me to be possible that the 
> protective electronics in both vehicle and charging system (Mode 3 
> columns and wall boxes, Mode 2 in-cable control protective devices, 
> ICCPDs) can be altered. In particular, one might worry about the Type 
> A and Type B residual current devices that are likely to be required 
> (Type A in a charging device, Type B in a car, although this is 
> currently under discussion in Germany). RCDs used to be 
> electromechanical, but the Type A and Type B boxes, as well as the 
> short-circuit and over-current protections that are usually 
> incorporated into the boxes as well, are primarily electronics. There 
> are also discussions about protective communication devices carried 
> inside the cables, such as a control pilot. The electronics needed to 
> make such things functional would also potentially be susceptible to 
> SEPs and their atmospheric byproducts (that is, an increase in 
> cosmic-ray intensity).

As weight is a lesser problem than in aircraft, perhaps chargers and 
RCDs could be adequately screened or duplicated.

Martyn


>
> There have been events with MOSFETs in rail operation which have been 
> plausibly put down to cosmic-ray-induced SEUs. I don't know if (and, 
> if so, what) MOSFETs might be used in electric road vehicles.
>
> Kelly Mahoney also pointed me towards a 2011 document from the OECD: 
> http://www.oecd.org/governance/risk/46891645.pdf I haven't looked at 
> it yet.
>
> PBL
>
> Prof. Peter Bernard Ladkin, Faculty of Technology, University of 
> Bielefeld, 33594 Bielefeld, Germany
> Tel+msg +49 (0)521 880 7319  www.rvs.uni-bielefeld.de
>
>
>
>
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