Toshiba HV6CS-MU Installation Instruction
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Applicable standards pertaining to switching surges
Consult Table 2 for the standards applicable to VCB switching surges.
Table 2 Applicable Standards Pertaining to Switching Surges
Circuit
breaker
type
Load type
Rotating
machine *
1
Dry type
transformer
(insulation
resistance
below
class A)
Oil-immersed
transformer
(insulation
resistance
class A)
When there is
electronic
equipment on
transformer
low voltage
side
Phase advance
capacitor *
4,
*
5
Ordinary
Protected by CR
suppressor *
6
Protected by
surge
suppressor
No special
restrictions
Protected by CR
suppressor *
6
6.6 kV circuit:
No special
restrictions
up to 300 kVA
Low surge
type
No special
restrictions *
2
No special
restrictions *
3
No special
restrictions
Protected by CR
suppressor *
6
6.6 kV circuit:
No special
restrictions
up to 4000 kVA
*1. Mainly induction motors, but also includes synchronizing generators for private generator
equipment.
*2. Use a CR suppressor for surge protection when inching at 55 kW (75HP) or below and on
inductance regulators.
*3. Use an arrester for surge protection on circuits that require cutting off of excitation rush current.
*4. When the capacity of the group of capacitors exceeds 300 kVA, insert a series reactor (6%).
*5. For high-frequencies included in the applicable circuit, use 135% or below of the fifth harmonic
as established in the standards for phase advance capacitors (JIS C 4801).
*6. Table 3 shows the models of applicable CR suppressor.
Table 3 CR Suppressors
Circuit voltage
CR suppressor model
6.6 kV
NV60K304T1
(three-phase)