[SystemSafety] Hazard and Qualitative-Risk Analysis of Mode 3 Charging of Electric Road Vehicles

[Peter Bernard Ladkin]

For the last couple of years, a committee I chair in the standardardisation organisation for
electrotechology in Germany, the DKE, has been working on a hazard analysis and risk analysis of the
recharging procedure for electric road vehicles.

A year ago, we completed a draft high-level analysis for charging vehicles in so-called "Mode 3",
that is, using charging transformers, "charging stations", affixed to the infrastructure, say at the
roadside or in/on a building.

We are now considering Mode 2 charging, in which a portable transformer/control device called an
"In-Cable Control Protective Device" or ICCPD is attached by a cable to a non-dedicated circuit, say
a building circuit, on one side and to the vehicle to be charged on the other.

Oddly, the project to perform a HazAn/RiskAn is controversial, despite that the IEC Guide on Safety
says that all safety-related standardisation projects should incorporate a HazAn/RiskAn phase into
their process requirements. The DKE performed the HazAn/RiskAn because the charging infrastructure,
from fixed circuits to charging stations to the cables connected them to the car, do not otherwise
fall under a single entity, a company say, with end-to-end responsibility for the entire system.

Risk Analysis would normally require an assignment of numbers (probabilities or likelihoods) to
certain events happening, as required by say fault trees or event trees. We can't do that, because
no numbers are available for a new process such as this. So qualitative risks must be assessed. We
used a spec'd-down version of OHA for the hazard analysis and qualitative event trees to indicate risks.

The HazAn document is published now under the editorial names of myself and Bernd Sieker. Many
people contributed, but because of the sensitivity of commercial companies to their markets, other
contributors wished not to be named. They do include some very good electrical engineers indeed,
with whom I am delighted to have the privilege of working.

At the suggestion of the Committee, the Mode 3 document is currently available, at the moment only
in German, at http://www.rvs.uni-bielefeld.de/publications/Papers/HazAn_2012_09_13-pub.pdf . It is
deliberately short and simple to read, and we hope technically accessible. An English version will
slowly take shape.

Comments are *very* welcome.

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