Derating As A Function Of The Installation Altitude - Siemens SINAMICS G120P PM330 Installation Manuals

6.3.2

Derating as a function of the installation altitude

Voltage
The insulation clearances within the converter are measured for surge voltages in
accordance with overvoltage category III in compliance with EN 60664-1 for installation
altitudes up to 2000 m above sea level.
Use of an isolating transformer to reduce transient overvoltages to IEC 61800--5--1
By using the isolating transformer, overvoltage category III is reduced to overvoltage
category II. As a result, the requirements placed on the insulating capability of air are
reduced. An additional (input) voltage derating is not necessary if the following basic
conditions are met:
● The isolation transformer must be fed from a low-voltage or medium-voltage network; it
must not be supplied directly from a high-voltage network.
● The isolating transformer may be connect to one or more converters.
● The cables between the isolating transformer and the converters must be routed in such
a manner as to rule out direct lightning strike, i.e. it is not permissible that overland lines
are used.
● The following supply system types are permissible:
– TN supply systems with grounded star point (no grounded phase conductor)
– IT supply systems (operation with a ground fault must be limited to the shortest time
Note
The connected motors and power components must be considered separately.
Power Module PM330
Hardware Installation Manual, 10/2016, A5E32844552B AD
possible)
Technical specifications
6.3 Derating data
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