01-04 2026
Application of GIS Cable Accessories in Urban Distribution Networks
With the rapid development of urban modernization, urban distribution networks are facing continuous upgrading and transformation. The demand for high reliability, compact layout, strong environmental adaptability and long service life of power supply equipment is increasing day by day. Gas Insulated Switchgear (GIS), with the advantages of small footprint, high insulation performance, strong anti-pollution capability and long maintenance cycle, has been widely used in urban distribution networks, especially in urban central areas, industrial parks, high-rise building power supply hubs and underground substations. As a key connecting component between GIS equipment and high-voltage power cables, GIS cable accessories directly determine the insulation coordination, operation stability and fault-free operation cycle of the entire power supply system. This paper analyzes the technical characteristics of GIS cable accessories, their application scenarios in urban distribution networks, selection principles, installation requirements and operation and maintenance strategies, so as to provide reference for the design, construction and operation of urban distribution network projects.
GIS cable accessories are dedicated termination products used to connect cross-linked polyethylene (XLPE) insulated power cables to GIS equipment. They are usually designed as integrated, fully sealed and screened terminations, matching the SF6 gas insulation environment inside GIS. Different from conventional outdoor or indoor dry-type terminations, GIS cable terminations must meet strict requirements for electric field distribution, air tightness, partial discharge control and mechanical coordination. They are required to maintain stable electrical performance under long-term operating voltage, transient overvoltage and short-circuit impact, and at the same time ensure reliable insulation coordination with GIS internal conductors, shielding systems and basin insulators. Therefore, GIS cable accessories have higher technical thresholds in material selection, structural design and manufacturing processes.
In urban distribution networks, the voltage levels of GIS cable accessories are mainly 10kV, 24kV and 35kV, which cover the mainstream voltage systems of urban distribution. The core advantage of GIS equipment lies in its highly integrated and modular structure, which greatly saves urban land resources. GIS cable accessories are designed with compact structure and high dimensional accuracy, which can be directly embedded into the GIS flange or cable box without additional installation space. This feature is particularly important in urban core areas where land resources are scarce and underground space is limited. Underground substations, integrated pipe galleries and compact distribution stations widely use GIS to replace traditional air-insulated switchgear (AIS), and GIS cable accessories have naturally become essential supporting components.
Urban distribution networks are often located in densely populated areas, with complex operating environments, including high humidity, heavy pollution, coastal salt fog, typhoon and rain erosion, as well as the impact of urban construction vibration and electromagnetic interference. GIS cable accessories are mostly installed inside the closed gas compartment of GIS, completely isolated from the external environment. This structure fundamentally avoids the influence of moisture, dust, corrosive gases and bird damage on cable terminations, greatly reducing the probability of insulation flashover, partial discharge and external damage. Compared with conventional cable terminals, GIS cable accessories can maintain stable performance for a long time in harsh environments, effectively improving the power supply reliability of urban distribution networks and reducing the annual outage rate.
In terms of electrical performance, GIS cable accessories adopt precision-machined stress control structures and high-quality insulating materials, such as enhanced silicone rubber or ethylene-propylene rubber, with excellent partial discharge suppression and voltage endurance. The internal electric field is evenly distributed through the built-in capacitive or resistive stress control system, avoiding local field strength concentration that may lead to insulation aging or breakdown. In urban distribution networks, cable lines are dense, with many branches and frequent load fluctuations. GIS cable accessories can withstand large current shocks and voltage changes, maintain stable contact resistance and insulation performance, and avoid abnormal heating or insulation degradation at the joint between cables and switchgear.
The application of GIS cable accessories is also closely related to the development of intelligent and modular urban distribution networks. Modern urban distribution substations tend to adopt prefabricated and integrated design, and GIS equipment is often factory-assembled and tested as a whole. GIS cable accessories can be matched and installed in the factory, with controllable quality and high consistency, reducing the difficulty of on-site construction and debugging. After being connected to the distribution automation system, the operating status of GIS cable accessories can be monitored in real time through online monitoring devices such as partial discharge monitoring, infrared temperature measurement and overcurrent monitoring, realizing early warning of potential faults and supporting the intelligent operation and maintenance of urban distribution networks.
In the construction and renovation of urban underground integrated pipe galleries, GIS cable accessories show unique advantages. The pipe gallery integrates power cables, communication lines, water supply and drainage pipelines, etc., with narrow space and high requirements for fire protection, electromagnetic compatibility and safety. GIS cable accessories have excellent flame-retardant properties and low electromagnetic interference, and their fully enclosed structure will not affect other pipelines even in case of insulation faults. At the same time, because GIS equipment does not produce open arcs or external discharges during operation, it improves the overall safety of the pipe gallery and meets the strict safety standards of urban underground space.
When selecting GIS cable accessories for urban distribution networks, strict matching with voltage levels, cable cross-sectional areas, and conductor materials must be ensured. The accessories must comply with international and national standards such as IEC 60502 and GB/T 12706, and have complete type test reports, including partial discharge tests, power frequency voltage withstand tests, lightning impulse tests and thermal cycle tests. It is also necessary to confirm the dimensional interface parameters with GIS equipment manufacturers to ensure seamless connection and reliable sealing performance. In addition, for important load nodes such as urban central business districts, hospitals, transportation hubs and data centers, high-quality GIS cable accessories with longer design life and higher reliability should be selected to ensure uninterrupted power supply.
Installation quality is crucial to the long-term stable operation of GIS cable accessories. On-site construction must be carried out by professional technicians in strict accordance with process specifications. Key links include cable end cutting, semi-conductive layer treatment, conductor crimping, stress cone installation, sealing treatment and airtightness test. Special attention should be paid to keeping the construction environment clean and dry to prevent dust or moisture from entering the GIS cavity. After installation, air tightness detection, partial discharge detection and AC withstand voltage test must be carried out to confirm that the indicators are qualified before official operation.
In terms of operation and maintenance, GIS cable accessories require less routine maintenance due to their fully enclosed structure. However, in the daily operation of urban distribution networks, regular inspections are still needed, including infrared temperature measurement to detect abnormal heating, ultrasonic or ultra-high frequency partial discharge detection to judge internal insulation defects, and regular SF6 gas density monitoring to ensure that the gas insulation performance is normal. For important distribution nodes, online monitoring devices can be configured to realize 24-hour real-time status tracking, so as to quickly locate and eliminate hidden dangers and avoid large-scale power outages.
In summary, GIS cable accessories play an indispensable role in the construction and development of modern urban distribution networks. Their high reliability, compact structure, strong environmental adaptability and excellent electrical performance effectively solve the problems of limited land resources, complex operating environment and high power supply reliability requirements in urban areas. With the continuous advancement of urban distribution network automation, intelligence and underground construction, the application scope of GIS cable accessories will be further expanded. In engineering practice, standardized selection, precise installation and scientific operation and maintenance are important guarantees to give full play to the performance advantages of GIS cable accessories and support the safe, efficient and stable operation of urban distribution systems.
