Amsa da Yau da Tushen Yanzu da Ayyuka na RMU (Ring Main Units) na Kwalba

1. Yadda Ake Amfani Da Solid-Insulated Ring Main Units a Jikin Karamin Kirki na Mafi Tsawon Kirki

1.1 Amfani Da Take Taka a Filayen Gida a Birnin

Mafi girman muhimmin abubuwa na ring main units (RMUs) da karamin kirki sun hada da tashar tsari da kuma fuses. Wadannan abubuwan da suka taka wajen amfani su ne saboda cikakken sauyi, kudancin gida, da kuma kyauwar sana'ar. Su zai taimaka wajen bincike mai karfi da kuma taimaka kan karkashin kirki. An tabbatar da haka cewa adadin karamin kirki mafi yawa don RMUs na karamin kirki ita ce 1250A, da halayen adadin musamman shi ce 630A. Daga ma'anar insulanta, ana ci RMUs zuwa duwatsu: air-insulated da SF₆ gas-insulated. Suna taka wajen tsara karamin kirki da kuma kawo karamin kirki masu kudancin lokaci, da kuma sun bayar wasu abubuwa da suke taimaka kan kontrola da kuma inganci.

1.2 Vacuum Load-Switch RMUs Sun Bayar Isolation Gaps Mai Kyau

Tashar tsari da ake amfani da su a RMUs na air-insulated sun hada da dukkan da take taka: gas-generating, compressed-air, vacuum, da kuma SF₆. Idan an tabbatar da haka, SF₆ load switches sun zama tashar tsari mafi yawa a RMUs na air-insulated. Tashar tsari a wurare na kudancin gida suna da uku masu tattalin arziki: kawo karamin kirki, tsakanin gwargwadon lokacin, da kuma isolarci tsari.

1.3 Takaice Masu Tukuna Don Amfani Da Take Taka

Idan an tabbatar da haka, RMUs suna da kudancin gida. Saboda wannan yanayi, akwai tushen da ya kamata da kudancin gida (kamar tashar tsari na karamin kirki) da suka taka wajen amfani su ne saboda cikakken sauyi da kuma fuses na karamin kirki. Tushen RMUs suna iya yi aiki a tashar tsari, inda kuma fuses suna iya kawo karamin kirki masu kudancin lokaci. Takaice masu tukuna da ake yi wa wannan labaran abubuwa suna taimaka wajen kawo tsari na circuit breakers, amma wannan takaice tana da nasara ga kudaden karamin kirki masu musamman.

2.Tsarin Takaice da Koyarwuka Ta Fanni Na Solid-Insulated Ring Main Units

2.1 Takaice Masu Tukuna Don Pole Technology

Epoxy resin tana da take taka wajen amfani da shi a matsayin insulanta mai yawa a solid insulation, da kuma vacuum tana da take taka wajen amfani da shi a matsayin arc-quenching medium. Don in taimaka wajen samun abubuwa masu tukuna kamar tashar tsari da kuma isolation, idan an tabbatar da haka, mekanisumin tashar tsari ya kamata ake yi amfani da shi don in taimaka wajen samun kontrola masu tukuna kan systemin karkashin kirki, don in taimaka wajen inganci masu tukuna kan abubuwan da mutane. Insulanta mai yawa tana taimaka wajen kadan jirgin insulanta daga phase to ground a wurare, inda an kadan jirgin insulanta mai yawa daga 125mm zuwa kadan millimeters. Ba a yi amfani da SF₆ gas ba, tana kadan gurbin RMUs daga C-GIS na musamman. Da kuma, amfani da mekanisumin tashar tsari na yawan al'amuran tana taimaka wajen kadan adadin abubuwan da ke nan, tare da kuma taimaka wajen inganci masu tukuna kan abubuwan da ke nan.

2.2 Koyarwuka Ta Fanni Na Solid-Insulated RMUs

Saboda RMUs na air-insulated da SF₆ switches da kuma SF₆ gas-insulated, RMUs na solid-insulated suna da koyarwuka masu tukuna: Kafin an tabbatar da haka, tsarin wurare tana da take taka wajen amfani da shi saboda cikakken sauyi. Babban tashar tsari tana da take taka wajen amfani da shi saboda isolation component, tare da kuma bayyana bayyana. Insulanta mai yawa tana da take taka wajen amfani da epoxy resin sleeves da kuma insulating tubes. Wannan abubuwan suna taimaka wajen kadan tashin SF₆ liquefaction a filayen da take da rabi, da kuma tashin thermal expansion a filayen da take da ta'aya, tare da kuma taimaka wajen amfani da shi a filayen da take da karfi.

3.Masana Tana Da Iya Samu Lura a Solid-Insulated Ring Main Units

3.1 Teknologiyyar Insulanta da Surface Coating

Idan an tabbatar da haka, partial discharge formation tana da take taka wajen amfani da shi saboda voids. Takaice masu tukuna da ake yi wa sealing techniques tana da take taka wajen amfani da preheating metal molds, placing preheated components into the mold, slowly injecting under vacuum, and curing. Wannan takaice tana da take taka wajen amfani da shi saboda cikakken sauyi, amma tana da take taka wajen amfani da shi saboda kyauwar sana'ar. Incomplete bubble removal tana iya taimaka wajen samun voids masu yawa a solid insulation, tare da kuma tana iya taimaka wajen samun partial discharge during operation, tare da kuma tana iya taimaka wajen samun cracking of insulation components, tare da kuma tana iya taimaka wajen samun safe and reliable operation of equipment.

Don haka, ya kamata ake yi amfani da teknologiyyar encapsulation ta epoxy resin mai yawa. Da kuma, surface shielding tana da take taka wajen amfani da shi saboda performance, tare da kuma tana da take taka wajen amfani da shi saboda design and production. Babbuwan da ake yi amfani da shi saboda metallizing the surface of insulation materials tana da take taka wajen amfani da shi saboda reliable grounding, tare da kuma tana da take taka wajen amfani da shi saboda minimizing the impact of environmental factors, da kuma tana da take taka wajen amfani da shi saboda enhancing product performance. Idan an tabbatar da haka, akwai tushen solid-insulated RMUs da aka yi amfani da shi saboda lack of proper surface treatment, tare da kuma tana da take taka wajen amfani da shi saboda high partial discharge levels in supplied products.

3.2 Lack of Operation and Maintenance Experience

Solid-insulated RMUs suna da take taka wajen amfani da shi saboda technology mai yawa. Saboda lack of scientific and reasonable trial operation arrangements by power grids, tana da take taka wajen amfani da shi saboda current total operational volume is small, operational time is short, and provincial grid connections are incomplete. Idan an tabbatar da haka, a filayen da take da ta'aya, humidity, coastal, high-rainfall, and large diurnal temperature variation, tana da take taka wajen amfani da shi saboda practical issues need to be addressed. Comprehensive work experience must be accumulated nationwide to conduct targeted and forward-looking improvements to solid-insulated RMUs, continuously enhancing product safety and stability.

3.3 Development of Solid-Insulated RMU Equipment

In recent years, with the rapid development of China's distribution network, the technical level of the distribution system has significantly improved. SF₆ gas has been widely used in medium-voltage RMUs. From China's current development status, SF₆ gas offers the best overall performance. However, with the increasing awareness of environmental protection and the importance of natural conservation, the extensive use of SF₆ gas in RMUs poses certain environmental hazards and potential risks to human health. Therefore, reducing the use of SF₆ gas RMUs and promoting solid-insulated RMUs will be a primary goal for the development of high-voltage switchgear. Domestic manufacturers have anticipated this trend and have gradually begun developing and producing solid-insulated RMU products.

3.4 Optimization of Insulation Module Structure Design

The structural design of insulation modules must, while meeting functional, inspection, and installation requirements, aim to reduce material consumption and prevent residual stress. The presence of residual stress can cause internal and external cracks in solid insulation components, leading to partial discharge during operation and potential insulation breakdown. Therefore, in-depth research on the overall structure, thickness, and transitions of insulation modules is necessary, with consideration given to heat dissipation concepts.

3.5 Research and Design of Shielding Layers

The primary purpose of external design is to plan metal shielding grounding: first, in the event of insulation failure, to confine short-circuit faults to phase-to-ground only, reducing arc energy and fault risk; second, to maintain insulation performance in any environment without requiring cleaning of the module's outer surface, ensuring unchanged electric field distribution even with metallic foreign objects inside the cabinet.

4.Development Directions for Solid-Insulated Ring Main Unit Technology

4.1 Development of New High-Performance Insulating Materials

Although epoxy resin performs well as a solid insulation material, the casting process in vacuum ceramic arc-quenching chambers can damage raw materials. Therefore, developing advanced epoxy resins that surpass current material characteristics is essential. In 2014, the journal Science published an article on the discovery of a new recyclable thermosetting polymer, marking a significant advancement in the recycling of "polysalicylate" thermosetting plastics. This polymer exhibits high recyclability, addressing the issue that thermosetting plastics were previously non-recyclable. In the next decade, new products will increasingly utilize recyclable thermosetting materials.

4.2 Research on Internal Component Interface Connection Methods

Since solid-insulated RMUs are manufactured by encapsulating main circuit conductors and mounting parts within solid insulation, the inflexibility of embedded components necessitates standardized connections between different cast elements. The overall configuration of the RMU is linear, and connecting conductors must be cast with epoxy resin, requiring a certain degree of freedom during product rationalization. To address this, an interface technology using silicone rubber material for gate-to-conductor connections is proposed. This method enables standardization, allowing components to be interconnected and reasonably configured, reducing the design complexity of the overall insulated enclosure.

4.3 Market Promotion Prospects for Solid-Insulated RMUs

Solid-insulated RMUs feature a simple structure, compact size, non-toxicity, pollution-free operation, and environmental friendliness, aligning with the global green development concept. However, for a product to be successful, manufacturers must profit from sales, making market application a key focus. Understanding and meeting user needs is critical to the successful introduction of new products. The application prospects of solid-insulated products are analyzed based on user requirements.

4.3.1 Products Meeting Consumer Needs

During use, users first require that product technical parameters comply with relevant standards (technical specifications, national and industry standards, etc.) and obtain certification from the national power industry. As no specific standards currently exist for solid-insulated products, manufacturers must assist in establishing national or industry standards. It is reported that by December 31, 2002, claims for approximately 15 million tons of solid-insulated products had been filed.

4.3.2 High User Requirements for Distribution Network Products

Medium-voltage distribution equipment is a fundamental component widely used in power grids. With the continuous expansion of grid infrastructure, demand for medium-voltage equipment as a bridge between main networks and end-users is growing. Users require products with long service life, strong environmental adaptability, compliance with environmental standards, compact size, easy and quick installation, economic convenience, and a reliable operational history.

Solid-insulated RMUs have compact dimensions, with single load switch cabinet units measuring 860mm (depth) × 420mm (width) × 1200mm (height) or 850mm (depth) × 500mm (width) × 1600mm (height). Their size falls between that of air-insulated switchgear. Based on the above technical performance, solid-insulated RMUs provide enhanced personal safety. However, due to their relatively short operational history, only a limited number of units are currently in service across several Chinese factories. Given the limited operational data, it is currently impossible to evaluate the aging of epoxy insulation or determine inspection cycles.

Some domestic equipment manufacturers guarantee a product lifespan of over 20 years through advanced production facilities (workshops, molds, and automated laser welding). This represents a competitive advantage. Economically, current production of solid-insulated enclosures requires significant investment in specialized equipment, molds, and materials, resulting in higher market prices. Additionally, as power systems primarily use equipment bidding with a focus on low prices, SF₆ RMU modules have become increasingly cost-competitive, making it difficult for solid-insulated RMUs to gain market dominance in the short term.

4.3.3 Product Environmental Requirements

In most regions, users require normal operating environments not exceeding 40°C and not below -10°C. However, the increasing frequency of natural disasters globally has raised user demands. For example, RMUs installed in harsh environments must be fully enclosed and maintenance-free, ensuring complete insulation. Circuit breaker equipment must exhibit strong environmental adaptability, dust and moisture resistance, short-term immersion protection, and enhanced vibration resistance.

Casting internal components of circuit breakers with epoxy resin significantly increases the dielectric strength of insulating materials, preventing degradation due to vibration during transportation and use. Compared to gas-insulated RMU products, some manufacturers have conducted tests in Qinghai and coastal humid regions, as well as at altitudes around 4000m, achieving IP68 protection ratings. Therefore, solid-insulated RMU products better meet environmental requirements.

5.Conclusion

Based on the current development status of solid-insulated RMUs in China, the insulation technology is relatively mature, effectively addressing the shortcomings of air-insulated and gas-insulated RMUs, and suitable for special environments such as high-altitude regions. The adoption of solid-insulated RMUs can effectively promote the development of China's power grid and contribute to sustainable socioeconomic development. With growing attention to environmental protection, it can be confidently stated that solid-insulated RMUs have broad application prospects.