In a 10kV distribution network, the primary and secondary integrated ring network box is a widely used solution for terminal power distribution. Often referred to as a “ring cage,” this switch cabinet is designed for wiring in a ring network. Depending on the configuration, it can serve as a circuit breaker cabinet, a load switch cabinet, or a combination of high-voltage load switches and fuses. Small-sized SF6 load switchgear is commonly used as a ring cage due to its multiple advantages:

1. Cost-Effective

Even when a single SF6 switchgear includes a high-voltage fuse, project costs can be high. Compared to the roughly 30,000 yuan required to develop a circuit breaker cabinet, using integrated ring network boxes can save considerable investment, particularly when deploying multiple units.

2. Easy Maintenance

High-voltage load switches with fuses are highly effective for transformer maintenance. Fuses can interrupt short-circuit currents within 10ms, preventing transformer damage. In contrast, a circuit breaker requires multiple operational steps—including the maintenance room, engagement mechanism, and arc-extinguishing chamber—which can take up to 60ms. Quick interruption of short-circuit faults (within 20ms) reduces the risk of explosions, making ring cages a safer option.

3. Compact Design and Space-Saving

Ring cages are smaller than traditional circuit breaker cabinets or centralized switchgear, saving valuable indoor space. Secondary fusion ring cages can even be consolidated into a single box to form a ring network switch station, allowing rapid disconnection of power during common faults.

4. Simple Installation and Easy Expansion

Installing primary and secondary integrated ring main units is straightforward. There is no need for foundation pits or trenching—switch cabinets can be fixed directly on round steel supports. When expansion is required, additional cabinets can be installed alongside existing units and connected via horizontal bus ducts, providing flexibility for growing networks.

5. Rapid Power Supply Restoration

Each switch station in the integrated ring network box is equipped with an intelligent control module, enabling staff to monitor the operating status of the ring cage in real-time. This facilitates quick fault detection and efficient restoration of the power supply system.