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Rated Voltage / Current

12 kV / 630–4000 A (multiple ratings)

Rated voltage corresponds to the system voltage class the equipment belongs to and determines the insulation design margin. Rated current is the maximum continuous load current the breaker can carry long-term without exceeding its temperature rise limit; it is typically offered in several current ratings for incoming, feeder, and other panel types. When selecting a breaker, first determine the voltage class from the substation's system voltage, then choose a current rating no lower than the actual maximum load current — this is the primary basis for breaker selection.

Rated Frequency

50 Hz

The breaker must match the system frequency of the grid it is installed on. China and most markets in Asia, Africa, and Latin America use 50 Hz, while North America and parts of the Middle East and Central/South America use 60 Hz. Frequency affects contact travel matching and the design of certain auxiliary components. For projects exporting to 60 Hz grids such as North America, always confirm with the manufacturer before ordering that a 60 Hz version is available, to avoid equipment that cannot be commissioned due to a frequency mismatch.

Power-Frequency Withstand Voltage / Lightning Impulse Withstand Voltage

42 kV / 75 kV

Together these two values define the equipment's insulation level. The power-frequency withstand voltage is the 1-minute AC withstand test value, simulating relatively slow overvoltages such as switching surges. The lightning impulse withstand voltage uses the standard 1.2/50 µs waveform to simulate the transient high-voltage surge produced by a lightning strike. Both values must meet or exceed the insulation coordination requirements of the installation site — the higher the value, the stronger the equipment's ability to withstand overvoltage flashover.

Rated Short-Circuit Breaking Current

20 / 25 / 31.5 / 40 kA

This is the maximum current the breaker can safely interrupt without damage when a short-circuit fault occurs on the system. Several standard ratings are usually offered for grids with different short-circuit capacities, and this value is the core indicator of the vacuum interrupter's arc-quenching capability. When selecting a breaker, choose a rating no lower than the maximum system short-circuit current at the installation point (with margin for future grid expansion), to avoid a breaking failure under the actual fault current.

Rated Short-Time Withstand Duration

4 s

This is the maximum time the breaker can carry the rated short-circuit current in the closed position without thermal damage or mechanical deformation. It evaluates thermal and dynamic stability rather than breaking capability. Four seconds typically covers the full fault-clearing time, including protection relay operation and trip output. A larger value indicates a higher safety margin under abnormal conditions such as protection delay or failure to trip.

Operating Sequence

O–0.3s–CO–180s–CO, etc.

This specifies the standard sequence of consecutive operations the breaker can perform without maintenance. Taking “O–0.3s–CO–180s–CO” as an example: open first (O), then close-open after a 0.3-second interval (CO, simulating auto-reclosing), then close-open again after a 180-second interval. This sequence verifies whether the equipment can meet the timing requirements of line-protection auto-reclosing, and must be checked when selecting breakers for applications such as overhead lines that require reclosing coordination.

Motor Voltage / Closing-Opening Voltage

AC/DC 220 / 110 / 48 V

This actually covers two independent circuits. The motor voltage drives the internal energy-storage motor that compresses the closing spring. The closing/opening voltage (control voltage) drives the trip and closing coils that release the spring energy to perform the opening and closing actions. Both can be AC or DC, with common ratings of 220 V, 110 V, and 48 V. DC power is usually supplied from the substation's battery system, ensuring reliable tripping even if the station's AC supply fails — a common choice for protecting the trip circuit. AC power costs less and is typically used where reliability requirements are relatively relaxed. Before ordering, always confirm the voltage against the customer's secondary control power supply on site; a mismatch can prevent the energy-storage motor from charging properly, or cause the opening/closing coils to fail to operate or operate incorrectly.

Standards Compliance

GB, IEC, CE

GB/GB⁄T are Chinese national standards and form the basic basis for tendering and acceptance on domestic grids. IEC (such as the IEC 62271-100 series) is the International Electrotechnical Commission standard, widely adopted across Belt and Road countries, Southeast Asia, the Middle East, Africa, and most other overseas markets, and is typically a mandatory technical requirement in international tenders. CE marking is required for compliance in the EU market — none of these can be omitted. Export projects should verify that all required certifications are complete and that the certificates are the latest valid versions for the target market.