Commissioning
Sageon III Power System
PM990-8800-00, Rev. 9
3-8
FIGURE 3-6
-THREE PHASE FEED (PHASE TO PHASE)
Surge protection requirements
The rectifiers are internally protected for surges up to 6kV/3kA. For higher levels of protection, particularly for sites with high
incidence of lightning or switching surges, additional surge protection is required on the AC feed to the Power plant. Typically surge
arrestors with a 10kA-40kA rating are required with the highest level of protection being provided when arrestors are connected
between phase-neutral (x3 phases) and between phase/neutral-earth (x 3 phases).
Other arrangements (for 3-phase “Y”) with similar levels of protection are also possible as shown below. The voltage rating of the
arrestor should be selected based on the maximum AC voltage likely to appear on the line. The arrestor should limit the voltage to
<1200V – 1400V at the rated maximum pulse current.
