Application Of The X-Ray Emission Standards - ABB VD4G-25 Installation And Operating Instructions Manual

V D 4 G I N S TA L L AT I O N A N D O P E R AT I N G I N S T R U C T I O N S
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10. Application of the X-ray emission Standards

One of the physical properties of vacuum insulation
is that X-rays could be emitted.
The specific tests performed at the PTB laboratories
(Physikalisch-Technische Bundesanstalt, in
Brunswick - Germany) show that local emission at a
distance of 10 cm from the interrupter or pole
surface, does not exceed 1 mSv/h.
This means that:
• use of vacuum interrupters is absolutely safe at
rated service voltage;
• application of withstand voltage at power
frequency (according to the IEC 62271-100 and VDE
0670
• standards) is safe;
• voltage higher than the withstand voltage at
power frequency or than a direct current test
voltage (specified in the IEC and VDE standards)
cannot be applied;
• in interrupters with open contacts, limitation of
the above-mentioned local phenomena depends
on maintaining the specific gap between contacts.
This condition is intrinsically guaranteed by correct
operation of the operating mechanism and by the
settings of the transmission system.