How ABB VD4 high altitude?
Standard vacuum circuit breakers for elevation of 1000m and below the place, because the insulating property of air decreases with increasing altitude, it must consider the impact of this phenomenon on the switch such as the use of external insulation at high altitude. Interrupter internal insulation will not be affected, because of its insulating ability is guaranteed by the vacuum. If the switching devices installed in 1000m altitude over the area, at the design stage of the insulating member, that should take into account the effects of altitude, including switchgear and circuit breakers and other components.
According to the standard GB / T11022 and IEC 60694 of the correction coefficient, when installed in the 2000m altitude correction factor of 1.13 to 12kV voltage level, for example, means that the circuit breaker must be in the standard altitude (1000m and below) has the ability to withstand higher insulation level (up to 1.13 times the standard product), that meet the power frequency withstand voltage: 42 × 1.13 = 47.5kVrms; lightning impulse withstand voltage to meet: 75 × 1.13 = 84.7kVp.
To meet the needs of some customers a higher altitude, by taking measures to strengthen the insulation, at present, ABB Xiamen Switchgear Co., Ltd. of 12kV VD4 vacuum circuit breaker can be installed through a specially designed rear at an altitude of 2000m and below the place, the program based on ABB UniGear ZS1 switchgear has been verified. It should be noted that, for this high-altitude circuit breaker ABB provides a number different from the standard circuit breaker sales, please pay attention to the customer when ordering distinction.