Advantages & Applications of Low-Voltage Vacuum Circuit Breakers Mga Advantages & Applications sa Low-Voltage Vacuum Circuit Breakers

Mga Low-Voltage Vacuum Circuit Breakers: mga Advantages, Application, ug Technical Challenges

Tungod sa ilang mas mababang voltage rating, ang mga low-voltage vacuum circuit breakers adunay mas gamay nga contact gap kumpara sa medium-voltage types. Sa matag ka gamay nga gaps, ang transverse magnetic field (TMF) technology mas superior kaysa axial magnetic field (AMF) sa pag-interrupt sa high short-circuit currents. Sa panahon sa pag-interrupt sa dako nga currents, ang vacuum arc tend to concentrate into a constricted arc mode, diin ang localized erosion zones mahimong magabot sa boiling point sa contact material.

Batasan ang proper control, ang overheated areas sa contact surface emit excessive metal vapor, diin mahimong lead to dielectric breakdown sa contact gap under the transient recovery voltage (TRV) human sa current zero, resulta niini ang interruption failure. Ang pag-apply og transverse magnetic field—perpendicular sa arc column—sa vacuum interrupter drives the constricted arc to rapidly rotate across the contact surface. Kini significantly reduces localized erosion, prevents excessive temperature rise sa current zero, ug thereby greatly enhances the breaker’s interrupting capability.

Mga Advantages sa Vacuum Circuit Breakers:

• Ang Contacts require no maintenance

• Long operational life, with electrical life almost equal to mechanical life

• Ang Vacuum interrupters can be mounted in any orientation

• Silent operation

• Walay risk of fire or explosion; ang arc is fully contained within the sealed vacuum chamber, making them suitable for hazardous, explosion-proof environments such as coal mines

• Performance is unaffected by surrounding environmental conditions such as temperature, dust, humidity, salt fog, or altitude

• Capable of withstanding high voltages across very small vacuum gaps

• Current interruption typically completed at the first current zero crossing

• Environmentally friendly and easily recyclable

Ang mga low-voltage vacuum circuit breakers adunay sama nga comprehensive protection, extensive measurement capabilities, ug rich diagnostic features as conventional Air Circuit Breakers (ACBs). Apan, sila offer superior advantages, including higher electrical and mechanical endurance, greater number of rated short-circuit breaking operations, stronger arc-quenching capability, ug true "zero arc flash" performance.

Kini nga characteristics make them especially suitable for harsh environments ug high-voltage low-frequency systems such as AC690V ug 1140V in TN, TT, ug IT configurations—commonly found in photovoltaic ug wind power applications. Sila enable high-voltage collector systems that reduce transmission losses. Beyond line protection, kini nga breakers can also protect motors (meeting GB50055 requirements) ug generators (meeting GB755 standards), providing users with a safer, more reliable, ug comprehensive low-voltage power distribution protection solution.

Bakit Wala Mas Widespread ang Usage sa Vacuum Circuit Breakers sa Low-Voltage Applications?

Ang primary reason lies in the significant energy demands sa operating mechanism:

Ang mga low-voltage circuit breakers typically employ lightweight operating mechanisms with compact components. In contrast, ang vacuum circuit breakers require substantially more operating energy—especially those designed for high-breaking-capacity applications. Tungod sa ilang gamay nga contact gap, extinguishing the arc requires intense energy. To withstand electromagnetic forces during fault interruption, ang high contact pressure is essential. For example:

• A 31.5kA vacuum breaker requires approximately 3200N contact force.

• To maintain adequate pressure after contact wear, ang contact travel of 4mm is needed.

• Consequently, ang total energy required from contact engagement to full closure is much higher than that of air circuit breakers.

Specific energy requirements include:

• 45 joules for a 40kA breaker (contact force: 4200N)

• 63 joules for a 50kA breaker (contact force: 6200N)

Thus, ang operating mechanism must be significantly reinforced to meet these demands. Para sa 100kA low-voltage application, ang energy required by a vacuum interrupter exceeds the capacity of standard low-voltage operating mechanisms.

A complete upgrade is necessary—larger energy storage springs, increased spring compression stroke, etc. Some existing mechanisms have minimal compression (e.g., only 25mm), ug even increasing spring stiffness cannot deliver sufficient energy. Instead, mechanisms with longer stroke are required. As seen in medium-voltage vacuum breakers, cam-driven springs often extend over 50mm, enabling sufficient energy storage. Additionally, ang overall mechanical strength, hardness, ug rigidity of the operating mechanism must be enhanced to handle the high forces involved.