Overview
The ZW32-24 is a three-phase AC 50ØHz, 24 kV outdoor high voltage vacuum circuit breaker for breaking and making load currents and frequent operation, used in the construction and retrofit of urban, rural, mine and railway distribution networks. Miniaturised, maintenance-free and intelligentised, it is a green, pollution-free design built on domestic materials and international technology.
It complies with GB 1984-2003 and DL/T 402-2007 / DL/T 402-2000 ordering conditions for 12 kV–40.5 kV vacuum circuit breakers, and is offered in two ratings — 630 A / 20 kA and 1250 A / 25 kA — with an optional integrated isolating switch (G) that gives a visible break point for maintenance safety.
Model Designation
- Z – Vacuum circuit breaker
- W – Outdoor type
- 32 – Design sequence number
- 24 – Rated voltage (kV)
- T – Spring operating mechanism
- □ – Rated current (A): 630 or 1250
- □ – Rated short-circuit breaking current (kA): 20 or 25
- G (suffix option) – With integrated isolating switch
Construction
The ZW32-24 combines five features engineered for reliable outdoor service. The stainless-steel enclosure uses a zinc-rich anti-rust treatment and a UV-resistant clear coat for excellent corrosion and salt-fog resistance. The APG solid-insulation poles are silicone-rubber encapsulated, giving a compact size, strong anti-condensation performance and long, maintenance-free life. The spring operating mechanism (manual or electric, with optional remote-control and surge-avoidance closing) needs no more than 70 W of external supply and uses a buffer device for small rebound and low noise. The arc extinguishing chamber is stainless-steel brazed without plating and ceramic-metallisation sealed above 130 MPa in a single process for low leakage. The current transformer uses a soft-magnetic core with epoxy-resin and silicone double insulation for large capacity, a high dynamic-stability multiplier and high accuracy.
Technical Parameters
Rated Operating Parameters
| No. | Item | Unit | 630 A rating | 1250 A rating |
|---|---|---|---|---|
| 1 | Rated voltage | kV | 24 | 24 |
| 2 | Rated frequency | Hz | 50 | 50 |
| 3 | Rated current | A | 630 | 1250 |
| 4 | Rated short-circuit breaking current | kA | 20 | 25 |
| 5 | Rated peak withstand current (peak) | kA | 50 | 63 |
| 6 | Rated short-circuit making current (peak) | kA | 50 | 63 |
| 7 | Rated short-time withstand current / duration | kA/s | 20 / 4 | 25 / 4 |
| 8 | Rated operating sequence | – | O–0.3s–CO–180s–CO | |
| 9 | Mechanical life | ops | 10,000 | |
| 10 | Rated short-circuit breaking times | ops | 20 | |
| 13 | Weight | kg | 115 | |
Insulation Level
| Item | Value |
|---|---|
| 1-min power-frequency withstand voltage (wet) – phase-to-phase / to ground / open contact | 50 / 65 kV |
| 1-min power-frequency withstand voltage (dry) – phase-to-phase / to ground / open contact | 65 / 79 kV |
| Secondary circuit 1-min power-frequency withstand voltage | 2 kV |
| Lightning impulse withstand voltage (peak) – phase-to-phase / to ground / open contact | 125 / 145 kV |
Service Conditions
- Ambient temperature: −40 °C to +40 °C
- Air relative humidity: daily average ≤ 95%, monthly average ≤ 90%
- Altitude: ≤ 3000 m
- Wind pressure: ≤ 700 Pa (equivalent to wind speed 34 m/s)
- Air pollution degree: Grade IV (creepage-distance ratio ≥ 31 mm/kV)
- Ice thickness: ≤ 10 mm
- Site free from fire, explosion, severe pollution, chemical corrosion and violent vibration
Installation & Wiring
Installation Diagram
The ZW32-24 is pole-mounted outdoors in two frame versions: the standard ZW32-24/T and the ZW32-24G/T with an integrated isolating switch (taller body, wider terminal span). Maintain adequate clearance for switching and maintenance, and make all primary and secondary connections to local utility standards.
Outline Dimensions
| No. | Item | Unit | ZW32-24/T | ZW32-24G/T |
|---|---|---|---|---|
| 1 | Overall height | mm | 970 | 930 |
| 2 | Overall base width (front view) | mm | 1056 | 1280 |
| 3 | Adjacent pole spacing | mm | 580 / 380 | 1056 |
| 4 | Side-view overall length | mm | 510 | 980 |
| 5 | Mechanism box height | mm | 315 | – |
| 6 | Lower frame height | mm | 209 | – |
| 7 | Base mounting hole offset | mm | 160 | 160 |
Selection & FAQs
Selection & Ordering Guide
When specifying the ZW32-24, confirm: rated current (630 A or 1250 A), the matching breaking capacity (20 kA or 25 kA), mechanism type (manual or electric), whether an integrated isolating switch (G) is required, and the controller / remote-control scheme for the intended automation level.
FAQ
- What is the difference between the 630 A and 1250 A ratings?
- The 630 A version is rated for 20 kA breaking with a 50 kA peak making/withstand current, while the 1250 A version is rated for 25 kA breaking with a 63 kA peak making/withstand current. Both share the same 24 kV rated voltage, spring mechanism and insulation levels.
- What does the G suffix mean?
- The G suffix denotes an integrated isolating switch that provides a visible air break point for maintenance safety. It is not rated to interrupt load or fault current and must only be operated after the breaker has opened.
- Why is APG solid insulation used for the poles?
- APG (auto-pressure gel) silicone-rubber encapsulation gives a compact pole with excellent anti-condensation performance, long working life and reliable insulation in harsh outdoor environments, with no oil or gas to maintain.
- What standards does the ZW32-24 comply with?
- GB 1984-2003 (High-voltage alternating circuit-breakers), DL/T 402-2007 (ordering technical conditions) and DL/T 402-2000 for 12kV–40.5kV high voltage vacuum circuit breakers.
- Can the mechanism be operated remotely?
- Yes. The spring mechanism is available in manual and electric forms and can be fitted with a remote-control device and a surge-avoidance closing device. The required external supply does not exceed 70 W, so back-up power is easy to provide.
- What is the mechanical and electrical service life?
- Mechanical life is rated at 10,000 operations and the vacuum interrupters are rated for 20 short-circuit breaking operations. The arc chamber is sealed at 130 MPa in a single process for long maintenance-free life.