Poznámky redaktora
Special Applications 189
OV like but with lower requirements
Definition
- Circuits with enhanced availability requirements
Examples:
- Power distribution systems installations
- Lines outside buildings protected additional provisions for
protection
OV Circuits which are directly connected the contact outside lines,
without any protective devices against overvoltages close the
connection point and which may endangered lightning or
switching overvoltages
Example:
- Lines outside buildings protected only inherent protection
5.2.1:
Dust deposit Humidity
PD pollution,
non-conductive, well protected
dry;
no condensation
PD noil-conductive, protected, temporary
conductivity caused condensation
rare, short temporary
condensation
PD low conductivity
(caused condensation)
frequent condensation
PD low conductivity damp,
long time condensation
PD occasionally conductive,
with periodic cleaning
rain, snow, ice
PD occasionally conductive,
coming from heavy pollution
rain, snow, ice
PD occasionally conductive,
coming from very heavy pollution
rain, snow, ice
* fixed installations only
.2 Definition degrees pollution, based VDE 0115
Table 5.1
