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With the global emphasis on environmental protection and the gradual tightening of greenhouse gas emission policies, the power equipment industry is accelerating its transformation towards a green and low-carbon direction. Gas-insulated ring network switchgear (RMU), as the core equipment of medium-voltage power distribution systems, traditionally relies on sulfur hexafluoride (SF6) gas to achieve insulation and arc extinguishing functions. However, the global warming potential (GWP) of SF6 is extremely high (about 23,900 times that of carbon dioxide), and its atmospheric lifetime is long, making it a key target for emission reduction in the power industry.
This article will focus on the core characteristics of low GWP gases and deeply analyze the technical realization of the environmental protection gas ring cabinet series CLH-12 / 24 series. Through relevant data and testing to verify the actual performance of low GWP gases, explain the application scenarios and industry value of the product, and provide a reference for the selection and application.
Low GWP gases refer to environmentally friendly gases with a global warming potential much lower than SF6 (usually GWP < 100).In the field of gas-insulated ring network switchgear, common low GWP gases include nitrogen (N2), dry air, and other pure gases, as well as mixed gases composed of a variety of environmentally friendly gases. The core advantage of this kind of gas lies in its environmental protection, while its insulation performance and arc extinguishing ability are the key to ensuring the reliable operation of the equipment.
The insulating performance of gas is usually evaluated by dielectric strength, that is, the maximum electric field strength that the gas can withstand without breaking down. Although the dielectric strength of nitrogen and other single low-GWP gases is lower than that of SF6, their insulation performance can be fully met in medium-voltage power distribution systems (12 kV-24 kV) through technical optimization such as pressure regulation, electrode shape design, and even pressure measures. For example, when the gas pressure is controlled at 0.02 MPa (relative pressure at 20 ℃), the dielectric strength of nitrogen can reach the insulation level required by 12kV- 24kV equipment.
Arc extinguishing is a key process in the opening and closing of circuit breakers to extinguish the arc and avoid equipment damage and power grid faults. Nitrogen and other low GWP gases achieve arc extinction through thermal shrinkage and cooling effects: the high temperature generated by the arc heats the gas, causing it to expand rapidly; Subsequently, the gas expands and cools, reducing the arc temperature below the critical temperature to maintain the arc, thus extinguishing the arc. Although the arc extinction speed of low-GWP gas is slightly lower than that of SF6, the optimized design of the vacuum circuit breaker mechanism can effectively improve the arc extinction performance and meet the short-circuit opening current requirements of the medium-voltage system.
| Performance Indicators | Low GWP Gas (Nitrogen) | SF6 Application Significance | Application Significance |
| Global Warming Potential (GWP) | 1 | 23900 | Low GWP gases significantly reduce greenhouse gas emissions. |
| Atmospheric Lifetime (Years) | ~114 | 3200 | Low-GWP gas has a short residence time in the atmosphere, resulting in less environmental impact. |
| Dielectric Strength (kV/cm, 0.1MPa) | 15-18 | 25-30 | Low-GWP gas meets insulation requirements through pressure regulation and structural optimization. |
| Arc Extinguishing Capability | Good | Excelente | Reliable arc extinguishing is achieved through low-GWP gas combined with optimized mechanism design. |
| Environmental Toxicity | Non-toxic | Non-toxic | Both gases are safe for human health and the environment. |
| Coste | Bajo | Alta | Low GWP gases offer significant cost advantages, reducing equipment manufacturing costs. |
In order to give full play to the performance advantages of low-GWP gases and ensure the reliability of equipment, in the development of the CLH-12 / 24 series environmental protection gas-insulated ring network cabinet, A series of targeted technological innovations and optimizations have been carried out, forming a modular RMU product with excellent performance, environmental protection, and safety.
The CLH-12/ 24 series adopts a fully sealed stainless steel shell design, which can effectively isolate the external environment and prevent gas leakage. The product’s gas box protection level reaches IP67, and the shell protection level reaches IP41, ensuring stable operation in harsh environmental conditions such as dust, moisture, and extreme temperature (-40 ℃ ~ + 70 ℃). At the same time, the product adopts a modular design, which can flexibly combine different functional units (such as load switch unit, vacuum circuit breaker unit, PT unit, etc.) according to the actual needs of the distribution system, so as to realize personalized customization and flexible expansion.
Vacuum circuit breaker mechanism: The product is equipped with a high-performance vacuum circuit breaker mechanism, which has a fast tripping function and a complete interlocking device. It adopts a rigid interlocking method to minimize the risk of misoperation. The arc extinguishing chamber is made of high-quality insulating material, fixed by end-face connection, ensuring stable overtravel and contact gap, and the local discharge current is less than 20pC at 1.1 times the rated voltage.
Isolating switch: The isolating switch adopts the three-position design of closing, opening and grounding, which is stable, safe and reliable in operation; The optimized design of the conductor contact surface improves the conductive performance and operating stability, and adopts equal pressure measures to ensure the balance of the electric field, so there is no need to set additional insulating plates between phases.
Gas system: The product uses nitrogen as the insulating and arc extinguishing gas (GWP = 1), the rated gas pressure is 0.02 MPa (relative pressure at 20 ℃), and the annual leakage rate is ≤0.01%, ensuring the long-term stable operation of the gas system. The gas box is equipped with pressure monitoring devices to realize real-time monitoring of gas pressure and timely alarm of pressure abnormality.
The CLH-12/ 24 series is equipped with advanced intelligent monitoring components, which can collect gas pressure, equipment temperature, operation status, and other data in real time, and transmit the data to the power grid monitoring system through the communication interface. This not only realizes the predictive maintenance of the equipment, but also improves the intelligence level and operation efficiency of the distribution system, which is in line with the development trend of the smart grid.
In order to verify the insulation performance, arc extinction performance, and overall reliability of the environmental protection gas-insulated ring network cabinet series CLH-12 / 24, Chuanli conducted a series of strict type tests and performance tests on the product, and the test results fully meet the requirements of relevant international standards (IEC 62217 series).
The product has passed the industrial frequency withstand voltage test and the lightning strike withstand voltage test. The test data shows that under the rated voltage of 12kV/ 24kV, the withstand voltage between phases and relative to the ground is 42kV (1min), and the withstand voltage of a lightning strike (peak) is 75kV. The isolation fault withstands 48 kV (1 min) at 50 Hz, and withstands 85 kV (peak) at lightning impulse. These data show that the insulation performance of products using low GWP gases is stable and reliable, and can effectively prevent insulation breakdown.
The rated short-circuit breaking current of the CLH-12/ 24 series vacuum circuit breaker unit is 20kA, and the rated peak withstand current is 50kA. Through the short-circuit opening test, the product can quickly extinguish the arc within the prescribed time when a short-circuit fault occurs, the opening performance is stable, and it can effectively protect the power grid and equipment from damage.
The product has passed the mechanical life test, and the mechanical life of the load switch/circuit breaker is up to 10,000 operations, and the mechanical life is up to 3,000 operations of the isolation switch/grounding switch; At the same time, through high and low temperature cycling test, humidity test and corrosion test, it is proved that it can maintain stable performance in long-term operation and harsh environmental conditions.
| Performance Parameters | Index Values | Unidades |
| Tensión nominal | 12/24 | kV |
| Corriente nominal | 630 | A |
| Rated Short-Time Withstand Current (4s) | 20 | kA |
| Corriente nominal de pico soportada | 50 | kA |
| Corriente asignada de corte en cortocircuito | 20 | kA |
| Power frequency withstand voltage | 42 | kA |
| Tensión soportada al impulso del rayo | 75 | kA |
| Insulating Gas | Nitrogen (Low GWP Gas) | / |
| Rated Gas Pressure | 0.02 | MPa |
| Annual gas leakage rate | ≤0.01 | % |
| Vida mecánica | 10,000 | cycles |
| Protection clas | IP67/IP41 | / |
| Operating temperature range | -40 ~ +70 | ℃ |
As Chuanli‘s environmental protection switch gear, the representative product of the CLH-12/ 24 series environmental protection gas-insulated ring network cabinet has the characteristics of environmental protection, compact structure, modular design, and reliable performance, and is widely used in various medium-voltage distribution scenarios.
Urban power distribution network: Suitable for secondary distribution substations in commercial areas, high-rise buildings, and residential communities, with compact structure and space-saving installation, meeting the requirements of urban land intensification.
Industrial enterprises: Suitable for the harsh working environment of industrial enterprises with a lot of dust, high humidity, and large temperature differences, providing reliable power distribution protection for production equipment.
Infrastructure Engineering: Applied to airport, railway, expressway, subway, tunnel, and other infrastructure projects, with strong environmental adaptability and ensuring the continuity of power supply for key projects.
New energy power generation support: Compatible with new energy power generation systems such as photovoltaic power stations and wind power stations, realize green distribution, and meet the environmental protection requirements of new energy projects.
Promote the green development of the power industry: Products replace SF6 with low-GWP gases, significantly reduce greenhouse gas emissions, conform to the global low-carbon development strategy, and promote the transformation and upgrading of the power equipment industry.
Guarantee the stable and safe operation of the power grid: Excellent insulation and arc extinguishing performance provide reliable protection for the medium-voltage distribution system, reduce the occurrence of power grid faults, and improve the reliability of power supply.
Reduce operation and maintenance costs: The fully sealed design and low leakage rate reduce the frequency of gas replenishment and maintenance; the modular design facilitates quick maintenance and replacement of components, reducing operation and maintenance costs and downtime.
Enhance enterprise competitiveness: For power enterprises and engineering projects, choosing Chuanli environmental protection switchgear not only meets policy requirements and environmental responsibility, but also enhances the enterprise’s green image and market competitiveness.
Under the background of global environmental protection and low-carbon development, replacing traditional SF6 gas-insulated ring network cabinets with low-GWP gas-insulated ring network cabinets has become an irreversible trend in the power equipment industry. The core challenge of this transformation is to balance environmental performance and equipment reliability, that is, to ensure that low GWP gases can provide sufficient insulation and arc extinction capability while meeting environmental requirements.
In the future, Chuanli will continue to focus on the research and innovation of green power equipment, continuously optimize product performance, expand application scenarios, and launch more high-quality environmental protection switchgear products to meet the evolving market demand and make greater contributions to the global low-carbon development cause.
Q1: What kind of low-GWP gas is used in the CLH-12 / 24 series ring network cabinet?
A1: Using nitrogen (N2), GWP = 1, environmentally friendly, and non-toxic.
Q2: Can the insulation performance of the CLH-12/ 24 series meet the requirements of the 24kV system?
A2: Yes. Its power frequency withstand voltage reaches 42kV, which fully meets the insulation requirements of a 24kV system.
Q3: What is the annual gas leakage rate of the CLH-12/ 24 series?
A3: ≤0.01%, no need for frequent air replenishment, ensuring long-term stable operation.
Q4: Is the CLH-12/ 24 series suitable for outdoor harsh environments?
A4: Applicable. The gas box has a protection level of IP67, which can be adapted to -40 ℃ ~ + 70 ℃ and dusty and humid environments.
Q5: Can the CLH-12/12 series be customized according to the distribution requirements?
A5: Yes. It adopts a modular design and supports a flexible combination of functional units.
