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RT 2c: EMF – Revision of magnetic field limits. Risk communication approach Case public exposure Case worker´s exposure Martti Hyvönen MD, Environmental Director at Helsinki Energy Chairman of Eurelectric WG Environment and Society Chairman of EMF Forum in Finland
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RT 2c: EMF – Revision of magnetic field limits • Risk communication approach • Case public exposure • Case worker´s exposure Martti Hyvönen MD, Environmental Director at Helsinki Energy Chairman of Eurelectric WG Environment and Society Chairman of EMF Forum in Finland martti.hyvonen@helen.fi Phone: +358 50 364 8840 HYVONEN-FI-RT.2c
Communication - the implicit messages? • MF limit increased to 200 µT instead of 100 µT… • Power lines are visible - substations near people • EF limit decreased to avoid spark discharges … • DSO´s EMF actions are based on … • Health controls … HYVONEN-FI-RT.2c
Children´s playground under power line HYVONEN-FI-RT.2c
Children´s playground near power line City bridge(110 kV cable) 110 kV OH line; load 2 x 500 A 0,16 µT at playground fence HYVONEN-FI-RT.2c
Public exposure to distribution substation MF HYVONEN-FI-RT.2c
Public exposure to distribution substation MF • TransCat project – Categorization of indoor MV/LV transformer substations according to magnetic field exposure • 250 + 53 substations in Finland; by the structure of LV connection • MF ≥100 µT possible when bus bars or cables near ceiling • Measurement guide provided Kettunen K &al.: Magnetic field categorization in indoor MV/LV substations by the structure of the low voltage connection. Cired Conference Vienna 2007 • TransExpo project?? In the appartment above, MF ≥0,4 µT/24 h Hareuveny R, Kandel S, Yitzhak NM, Kheifets L, Mezei G: Exposure to 50 Hz magnetic fields in apartment buildings with indoor transformer stations in Israel. J Expo Sci Environ Epidemiol. 2010 HYVONEN-FI-RT.2c
Inspection round at a CCGT power plant 85 µT HYVONEN-FI-RT.2c
Inspection round at a CCGT power plant Steam T generator GT bus bar ≤ 1 µT 43 % of time max 401 µT(1732 µT) HYVONEN-FI-RT.2c
Work at distribution substations HYVONEN-FI-RT.2c
Work at distribution substations • MF-Safety project – Magnetic field safety in power distribution switchgears and substations • Evaluation of routine tasks with a simple flow chart • Basic restriction 10 mA/m2 is not exceeded when MF <500 µT. But, higher induced currents possible in non-homogenous fields. • The relation between MF and induced currents was similar to Dimbylov´s (2005) results. • Substation tasks and layouts can be modified in a simple way to reduce exposure. There was no need to restrain routine work. Keikko T &al: Magnetic field risk eavaluation of workers in indoor distribution substations. Cired Conference Prague 2009 HYVONEN-FI-RT.2c
Exposure to electric fields • High voltage lines are not a significant source of EF public exposure. However, EF guideline values (5 or 10 kV/m) can be exceeded mid-span in the Finnish countryside. • At 400 kV substation maintenance work EF up to 25 kV/m, but, induced current densities were below the limit value 10 mA/m2 • By grounding themselves skilled workers avoid spark discharges Korpinen L, Elovaara J, Kuisti H: Occupational exposure to electric fields and induced currents associated with 400 kV substation tasks from different service platforms. Bioelectromagnetics 32,1;79–83, Jan 2011 HYVONEN-FI-RT.2c
Communication - the implicit messages? • MF limit increased to 200 µT instead of 100 µT… • Power lines are visible - substations near people • EF limit decreased to avoid spark discharges … • DSO´s EMF actions are based on …0,4 µT «yearly average» – precaution? • Health controls: doctor´s magic touch? HYVONEN-FI-RT.2c