Toshiba HV6CS-MU operation manual Applicable standards pertaining to switching surges

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		Load type
breaker		Rotating	Dry type	Oil-immersed	When there is	Phase advance
type		machine *1	transformer	transformer	electronic	capacitor *4, *5
			(insulation	(insulation	equipment on
			resistance	resistance	transformer
			below	class A)	low voltage
			class A)		side
Ordinary		Protected by CR	Protected by	No special	Protected by CR	6.6 kV circuit:
		suppressor *6	surge	restrictions	suppressor *6	No special
			suppressor			restrictions
						up to 300 kVA
Low surge		No special	No special	No special	Protected by CR	6.6 kV circuit:
type		restrictions *2	restrictions *3	restrictions	suppressor *6	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)

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