National key energy-saving and low-carbon technology: switchgear replaces SF6 ring network cabinet/switchgear technology

1. Technical name: Compact and small atmospheric pressure air-insulated sealed switchgear instead of SF6 ring network cabinet/switchgear technology

2. Technology category: carbon reduction technology

3. Field and scope of application: Power switch for power transmission and distribution system in the power industry

4. The application status and industrialization of this technology

SF6 produced globally is mainly used in the power industry, 80% of which is used in switchgear. my country's power switchgear uses about 60,000 tons of SF6 gas annually. In 2015, the demand for 12kV medium voltage ring mains switch cabinets reached more than 300,000 units, most of which are SF6 ring mains switch cabinets. The compact and small atmospheric pressure air-insulated sealed switchgear has the characteristics of miniaturization, maintenance-free, equipment land saving, and wide applicability. Through the comprehensive use of uniform electric field, vacuum arc extinguishing and atmospheric pressure sealed box air insulation technology, the air insulation is complete. The equipment has the same performance as the SF6 ring main unit and can completely replace the SF6 ring main unit/switch cabinet. At present, this technology has been applied in many projects in the electric power, buckle end belt, public construction, petrochemical industry, communications and other industries. The project involves airports, rail transit, national defense engineering construction and other fields; at the same time, the buckle end belt products have been applied. Exported to Europe and applied in Sweden, Norway and other countries, the carbon emission reduction effect is significant.

Five, technical content

1. Technical Principle

Using technologies such as uniform electric field, vacuum arc extinguishing and atmospheric air insulation of sealed cabinets, the air-insulated complete set of equipment has the same performance as the SF6 ring main unit, completely replacing the traditional SF6 switch cabinet/ring main unit; at the same time, it is sealed by atmospheric pressure Technology makes the products have the characteristics of high reliability, maintenance-free, compact and miniaturized (the same size as SF6 inflatable gas insulation equipment) and so on. This technology completely replaces the traditional SF6 ring network cabinet, realizes zero emission of SF6, does not produce solid waste such as epoxy resin, has a large potential for carbon emission reduction, and has good economic and environmental benefits.

2. Key technology

(1) Uniform electric field integrated switch architecture technology

Air is used as the main insulating medium between the charged body and the ground and between the phases, and the technology of multiple safety margin insulation and vacuum circuit breaker module and isolating switch module with longitudinal single-phase isolation arrangement, large air insulation spacing, and large creeping distance design is adopted to achieve Five-station uniform electric field architecture.

(2) Snap-type end belt manufacturing technology for atmospheric air-sealed box with equalizing filter

The box body has an air-sealed box-like dry working condition, which effectively isolates dust, dirt, and humidity in the operating environment, and prevents pollution flashover accidents; and realizes the internal and external pressure equalization of the sealed box through a pressure equalizing filter, which is fundamentally solved In addition, the inflatable ring network cabinet switch cabinet is prone to leakage.

(3) Design technology of separate and concise spring operating mechanism

Through the separated and simple spring operating mechanism, the number of parts is reduced (only one-tenth of the traditional product), and the switch module can be split, upgraded and replaced, which solves the problem of high mechanical failure of the circuit breaker

Sixth, the main technical indicators

1. Atmospheric air-insulated sealed ring network switchgear has a rated voltage of 12kV, when the rated current is ≤630A, the breaking current is ≤20~25kA; when the atmospheric pressure air-insulated and sealed general-purpose switchgear has a rated voltage of 12kV and rated current ≥630A, it will break Current ≥20~25kA;

2. SF6 emission is zero;

3. Solid insulation material waste ≤10%;

4. The recovery rate of equipment materials is ≥90%.

7. Technical appraisal

The technology has obtained 9 national invention patents and 45 utility model patents; it passed all type tests at the European WARSAW test station in July 2010; it passed the inspection of the National High Voltage Apparatus Quality Supervision and Inspection Center of Xi’an High Voltage Apparatus Research Institute in March 2011. All type tests passed the new product technical appraisal organized by the Guangdong Economic and Information Commission in the same year; in 2016, it passed the result appraisal organized by the China Electricity Council.

8. Typical users and investment benefits

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

Typical case 1

Case name: Power Distribution Reconstruction Project of the Production and Dispatching Building of a Power Supply Bureau of Guangdong Power Grid

Construction scale: 5 sets of switchgear complete sets of equipment. Construction conditions: The original power distribution room will be transformed to improve the reliability of power supply, and the original product's two-circuit site will be increased to five-circuit. The main construction content: the original independent two-way maintenance equipment is transformed into a two-way incoming and outgoing automatic switch, two-way outgoing project; compact and miniaturized, maintenance-free equipment to replace the application of SF6 switchgear. The main equipment is 4 sets of 630/25 and 1 set of double-layer voltage transformer cabinet 12kV compact air-insulated atmospheric pressure sealed box switch cabinet. The total investment of the project is 650,000 yuan, the construction period is 3 months, the annual emission reduction is about 16tCO2, and the carbon emission reduction cost is -120~-80 yuan/tCO2. The annual economic benefit is about 350,000 yuan, and the investment recovery period is about 2 years.

Typical case 2

Case name: Electricity project of a trade logistics city in Xingning, Guangdong

Construction scale: 32 sets of switchgear complete sets of equipment. Construction conditions: Newly build 1# and 2# opening and closing stations for electricity consumption projects in a large-scale commercial logistics city. Main construction content: The original design of two independent construction power distribution switchgears, through the use of maintenance-free compact products to replace SF6 switchgear, the power distribution room is combined into a two-story, the main equipment is 32 630/2512kV compact Air-insulated normal pressure sealed box-type switchgear. The total investment of the project is 2.91 million yuan and the construction period is 6 months. The annual emission reduction is about 102tCO2, and the cost of carbon emission reduction is -120~-80 yuan/tCO2. The annual economic benefit is about 2 million yuan, and the investment payback period is about 1.5 years.

9. Promotion prospects and emission reduction potential

It is estimated that in the next 5 years, the promotion ratio of this technology will reach 35% of the demand for 12kV medium-voltage ring network cabinets/switch cabinets, about 350,000 units. The total investment of the project is about 34 billion yuan, and the annual carbon emission reduction potential can be about 110. Million tCO2.