The ZF□-550 / Y6300-63 GIS is a high-performance gas-insulated switchgear system designed for 550 kV transmission and substation applications. It features a rated current of 6,300 A, a rated short-circuit breaking current of 63 kA, and a rated short-circuit making current of 171 kA, ensuring safe and reliable operation under the most demanding grid conditions.

The circuit breaker adopts an advanced dual-break self-energy arc-extinguishing technology, delivering excellent interrupting performance, high insulation margins, superior gas tightness, and long mechanical endurance. The breaker is capable of up to 24 full-capacity short-circuit interruptions, which exceed the requirements of relevant domestic standards, with a mechanical endurance of 10,000 operations.

The disconnector achieves a bus-transfer current of up to 4,000 A, representing a leading level in China, while the inductive current switching capability meets the highest IEC Class C requirements. Multiple key performance indicators exceed the requirements of IEC and GB standards, placing the product at a high technical level both domestically and internationally.

The ZF□-550 / Y6300-63 GIS adopts a three-phase segregated metal-enclosed design, with all live parts sealed in grounded metal enclosures filled with SF₆ gas. It integrates major components such as circuit breakers, disconnectors, earthing switches, busbars, instrument transformers, surge arresters, and control cabinets. Flexible configurations including single busbar, double busbar, and one-and-a-half breaker schemes are available to meet various substation requirements.

The system is widely used for switching, protection, isolation, load transfer, and measurement in high-voltage transmission and substation systems.

Figure 1 Engineering Layout of ZF□-550 GIS