Description

The Dry Air Insulated Dead Tank VCB was born of superb technology and abundant production experience of Meidensha Corporation.It is a circuit breaker employing vacuum interrupters and dry air for insulation. In order to use no SF6, which is global warming gas, there is no fear to decomposition of gas due to current interruption. It is therefore a highly reliable and high-performance circuit breaker.

Feature

Dead Tank Type VCB optimized for green procurement. It uses dry air for insulation in place of the SF6 which is specified as a greenhouse gas. Our basic design concept is to realize the environmental factors in design (The 3Rs (Reduce, Reuse, and Recycle) + LS (Longuse & Separable)) and life-cycle cost (LCC) reduction as basic concepts.

• Contribution to global warming prevention

Dry air insulation are employed instead of SF6 gas insulation. GWP (Global Warning Potential) of SF6 is 23,900.

• Excellent breaking performance

Since each current breaking section employs a vacuum interrupter, insulation recovery characteristics are excellent. It exhibits superb characteristics in cases of short-circuit interruption and short line fault interruption.

• Sucient capability against multiple strokes and evolving faults

Since the vacuum interrupters used are of completely self-arc-diusion type, this circuit breaker is the only unit that is capable of disposing of multiple strokes and evolving fault currents.

• Reduction of maintenance labor

Use of vacuum interrupters in the current breaking sections eliminates requirements of inspection for these sections. Therefore, man-hours can be saved for maintenance and inspection.

Type and Ratings

Specifications

Construction

Overall construction

For each phase, a current breaking vacuum interrupter is accommodated in the grounded tank. The operation system is such that closing and tripping are effected by spring force.The operating mechanism and 3-phase interlinkage are assembled on a common base, which is installed on the frame legs.

Internal construction

The overall structure is composed mainly of grounded tank, vacuum interrupters (VI), insulating rods, bushings and main circuit terminals. Each grounded tank is filled with dry air maintained at a rated pressure of 0.5MPa-g (20℃).

Internal construction of vacuum circuit breaker

Dry air system

Outline drawing

Dimensions (72.5kV)

Dimensions (36kV)

Standard connection diagram

Performance

Performance of the circuit breaker has been designed in accordance with ANSI and IEC standard, and verified by type test. All products are shipped after confirmation of various performances by acceptance test based on these standards.

• Withstand voltage characteristics ：Performance of withstand voltage is assured at the specified dry air pressure. Even though the dry air pressure has been lowered to the alarming level, the required insulation level can be assured.In addition, even though this pressure lowers to the atmosphericpressure, the circuit breaker withstands the rated voltage.

• Current passing performance ：Since the main contacts are located under vacuum, their surfaces are never oxidized and current passing performance is therefore stabilized. In the closing mode of circuit breaker, a pressing force is exerted between main contacts by the effect of pressing spring and sufficient tolerance is assured against closing current and short-time current.

• Mechanical life ：Due to adoption of simplified operating mechanism, switching characteristics are extremely stabilized. Frequent switching performance has also been verified through continuous mechanical switching test by repeating switching operations more than 10,000 times.

• Electrical life ：Since current breaking is performed in the vacuum interrupter,arcing energy generated during current interruption is extremely low and contact erosion is minimal. This implies long contact life.Load current switching : 10,000 times

• Rated breaking current switching : 20 times