I. Technology Name: Compact Miniature Atmospheric Air-insulated Sealed Switchgear Technology Replacing SF6 Ring Main Unit/Switchgear

II. Technology Category: Carbon Reduction Technology

III. Field and Scope of Application: Power transmission and distribution system power switches in the electric power industry.

4. Current Application Status and Industrialization of the Technology

Globally, the majority of SF6 production is utilized in the power industry, with 80% being used in switchgear. In China, the annual consumption of SF6 gas in power switchgear is approximately 60,000 tons. By December 2015, the demand for 12kV medium-voltage ring main units and switchgear exceeded 300,000 units, most of which were SF6-insulated ring main units and switchgear. Compact, small-sized, atmospheric air-insulated sealed switchgear features miniaturization, maintenance-free operation, space-saving design, and broad applicability. By integrating technologies such as uniform electric fields, vacuum arc extinction, and atmospheric sealed enclosure air insulation, air-insulated equipment achieves performance equivalent to SF6-insulated ring main units, enabling complete replacement of SF6-insulated ring main units/switchgear. Currently, this technology has been applied in various projects across industries such as power, transportation, public buildings, petrochemicals, and telecommunications, including airports, rail transit, and national defense projects. Additionally, the products have been exported to Europe, with applications in countries like Sweden and Norway, demonstrating significant carbon emission reduction effects.

5. Technical Content

1. Technical Principle

Utilizing technologies such as uniform electric fields, vacuum arc extinguishing, and atmospheric pressure sealed enclosure air insulation, the air-insulated switchgear achieves performance equivalent to SF6 ring main units, fully replacing traditional SF6 switchgear/ring main units. Additionally, the atmospheric pressure sealing technology ensures high reliability, maintenance-free operation, and compact miniaturization (with dimensions identical to SF6 gas-insulated equipment). This technology completely replaces traditional SF6 ring main units, achieving zero SF6 emissions and generating no solid waste like epoxy resin, offering significant carbon reduction potential along with excellent economic and environmental benefits.

2. Key Technologies

(1) Uniform Electric Field Integrated Switch Architecture Technology %% Using air as the main insulation medium between live parts and ground as well as between phases, this technology adopts a longitudinal single-phase isolated layout, large air insulation spacing, and a design with multiple safety margin insulation and vacuum circuit breaker modules combined with disconnector modules to achieve a five-position integrated uniform electric field structure. %% (2) Manufacturing Technology for Sealed Air Cabinets with Voltage Equalization Filters %% The cabinet provides a dry working environment typical of sealed air chambers, effectively isolating dust, contamination, and moisture from the operating conditions to prevent pollution flashover accidents. Additionally, by incorporating voltage equalization filters, internal and external pressure equalization is achieved for the sealed cabinet, fundamentally addressing the leakage issues common in gas-filled ring main units (RMUs) and switchgear. %% (3) Design Technology for Compact and Separable Spring Operating Mechanisms

By employing a separate and simplified spring operating mechanism, the number of components is reduced (only one-tenth of traditional products), enabling the switch module to be disassembled, upgraded, and replaced, effectively solving the issue of high mechanical failure in circuit breakers.

(2) Manufacturing technology for atmospheric air-sealed enclosure with equalizing filter

The enclosure features a dry operating condition typical of air-sealed enclosures, effectively isolating dust, contaminants, and moisture from the operating environment to prevent contamination flashover accidents. By incorporating an equalizing filter, it achieves internal-external pressure balance in the sealed enclosure, fundamentally solving leakage issues common in gas-insulated ring main units and switchgear.

(3) Design technology for modular, simplified spring-operated mechanism

The modular and simplified spring-operated mechanism reduces component count (only one-tenth of traditional products), enabling switch module disassembly, upgrades, and replacements, thereby addressing the high mechanical failure rate of circuit breakers.

VI. Main Technical Specifications

1. The rated voltage of the atmospheric air-insulated sealed ring main unit switchgear is 12kV, with a rated current ≤630A and breaking current ≤20~25kA; the rated voltage of the atmospheric air-insulated sealed general switchgear is 12kV, with a rated current ≥630A and breaking current ≥20~25kA;

2. Zero SF6 emissions;

3. Waste from solid insulation materials ≤10%;

4. Equipment material recovery rate ≥90%.

VII. Technical Certification Status

This technology has obtained 9 national invention patents and 45 utility model patents. In July 2010, it passed all type tests at the European WARSAW Test Station. In March 2011, it completed all type tests at the National High Voltage Apparatus Quality Supervision and Inspection Center of Xi'an High Voltage Apparatus Research Institute, and in the same year, it passed the new product technical appraisal organized by the Guangdong Provincial Economic and Information Commission. In 2016, it successfully underwent the achievement appraisal organized by the China Electricity Council.

8. Typical Users and Investment Benefits %% Typical Users: State Grid Corporation of China, China Southern Power Grid, Sanya Phoenix International Airport in Hainan, South Sea Fleet, etc. %% Typical Case 1 %% Case Name: Power Distribution Renovation Project for the Production and Dispatching Building of a Power Supply Bureau in Guangdong Power Grid %% Construction Scale: 5 sets of switchgear complete equipment. Construction Conditions: The original power distribution room underwent a renovation to improve power supply reliability, with the original two-circuit site expanded to five circuits. Main Construction Content: Transformation of the original independent two-circuit incoming and outgoing line maintenance-type equipment into a project with two incoming lines equipped with automatic transfer switches and two outgoing lines; application of compact, miniaturized, and maintenance-free equipment to replace SF6 switchgear. The main equipment consisted of four 630/25 kV and one double-layer voltage transformer cabinet of 12 kV compact air-insulated normal-pressure sealed box-type switchgear. The total project investment was 650,000 yuan, with a construction period of 3 months. The annual emission reduction is approximately 16 tCO2, with a carbon reduction cost of -120 to -80 yuan/tCO2. The annual economic benefits generated were about 350,000 yuan, and the investment payback period was approximately 2 years.

Typical users: State Grid Corporation of China, China Southern Power Grid, Phoenix International Airport in Sanya, Hainan, South Sea Fleet, etc.

Typical Case 1

Project Name: Power Distribution Renovation Project for the Production Dispatching Building of a Power Supply Bureau in Guangdong Power Grid %% Construction Scale: 5 sets of switchgear complete equipment. Construction Conditions: The original power distribution room was renovated to improve power supply reliability, and the original two-circuit site was expanded to five circuits. Main Construction Content: The original independent two-circuit maintenance-type equipment was transformed into a project with two incoming circuits featuring automatic backup switching and two outgoing circuits; compact and miniaturized, maintenance-free equipment replaced the SF6 switchgear. The main equipment includes four sets of 630/25 and one double-layer voltage transformer cabinet of 12kV compact air-insulated normal-pressure sealed box-type switchgear. The total project investment is 650,000 yuan, with a construction period of 3 months, an annual emission reduction of approximately 16tCO2, and a carbon reduction cost ranging from -120 to -80 yuan/tCO2. The annual economic benefit generated is about 350,000 yuan, with an investment payback period of approximately 2 years.

Construction Scale: 5 sets of switchgear complete equipment. Construction Conditions: The original power distribution room will be upgraded to improve power supply reliability, with the original two-circuit site expanded to five circuits. Main Construction Content: The original independent two-circuit incoming/outgoing line maintenance-type equipment will be transformed into a project with two incoming lines equipped with automatic transfer switching and two outgoing lines; compact and miniaturized maintenance-free equipment will replace SF6 switchgear. The main equipment consists of 4 sets of 630/25 and 1 set of double-layer voltage transformer cabinet 12kV compact air-insulated normal-pressure sealed box-type switchgear. The total project investment is 650,000 yuan, with a construction period of 3 months. The annual emission reduction is approximately 16tCO2, and the carbon reduction cost ranges from -120 to -80 yuan/tCO2. The annual economic benefit generated is about 350,000 yuan, with an investment payback period of approximately 2 years.

Typical Case 2

Case Name: Power Supply Project for a Commercial Logistics City in Xingning, Guangdong

Construction Scale: 32 sets of switchgear complete equipment. Construction Conditions: New power supply project for a large commercial logistics city, including 1# and 2# switching stations. Main Construction Content: The originally designed two independently constructed distribution switching stations were merged into one two-story distribution room by replacing SF6 switchgear with maintenance-free compact products. The main equipment consists of 32 sets of 630/2512kV compact air-insulated normally sealed box-type switchgear. Total project investment is 2.91 million yuan, with a construction period of 6 months. Annual emission reduction is approximately 102tCO2, with a carbon reduction cost of -120 to -80 yuan/tCO2. The annual economic benefit generated is about 2 million yuan, with an investment payback period of approximately 1.5 years.

IX. Promotion Prospects and Emission Reduction Potential

It is estimated that in the next 5 years, the promotion rate of this technology could reach 35% of the demand for 12kV medium-voltage ring main units/switchgear, approximately 350,000 units. The total project investment would be about 34 billion yuan, with an annual carbon emission reduction potential of approximately 1.1 million tCO2.