High-voltage complete switchgear is the core equipment in the distribution process of power systems, and its operational reliability is directly related to grid stability and user power supply safety. Hidden dangers such as internal short circuits, aging insulation, and poor contact easily trigger fires, which not only damage equipment but may also lead to large-scale power outages or even casualties. Therefore, improving the reliability of high-voltage switchgear through scientific fire protection design has become a key issue in power equipment design and operation and maintenance. The following analysis covers five dimensions: material selection, structural optimization, proactive fire extinguishing, monitoring and early warning, and operation and maintenance management:

1.Precise selection of flame-retardant and insulating materials

Materials are the foundation of fireproof design. The cabinet shell prefers to use highly flame-retardant steel plates (compliant with GB/T 17478 standard, oxygen index ≥32%), which is not easily flammable at high temperatures and can slow the spread of flames; Internal insulating components (such as busbar brackets and insulators) use arc-resistant epoxy resin composites or PTFE. These materials are heat-resistant (long-term operating temperatures can exceed 150°C) and have stable insulation properties, reducing the risk of short circuits and fires caused by insulation breakdown. Cable selection should use flame-retardant cross-linked polyethylene insulated cables, which have low smoke density and low toxic gas emissions during combustion, reducing the likelihood of fire spread. By utilizing the material's flame retardancy and insulation stability, the probability of fire is reduced from the source.

2.Compartmentalized Structure and Fire Sealing Design

Structural optimization is key to preventing the spread of fires. Using a compartmentalized design, the circuit breaker room, busbar room, cable room, and instrument room are physically isolated by aluminum silicate fireproof panels (fire resistance limit≥ 1 hour), achieving "localized faults"—even if a fire breaks out in one compartment, it will not quickly spread to other areas. The ventilation system must balance heat dissipation and fire protection: install vents with fire dampers that automatically close when the temperature exceeds the set value (e.g., 70°C), blocking flames from spreading through the ventilation channels. The bottom of the cable room is sealed with fireproof mud or fireproof wrappers to prevent flammable gases from entering the cabinet and to block the flame path along the cable.

3.Integrated application of active fire extinguishing systems

Active firefighting is the core method for controlling early-stage fires. Install small automatic fire extinguishing devices inside the cabinet, such as hot aerosol fire extinguishing systems or ultrafine dry powder fire extinguishing systems:

- The thermoaerosol fire extinguishing device responds quickly (≤5 seconds), releasing metal oxide aerosols that are non-conductive and pollution-free, effectively extinguishing electrical fires in enclosed spaces;

- The ultra-fine dry powder fire extinguishing device has high extinguishing efficiency, quickly covering the fire source and suppressing flame rekindling.

At the same time, the cabinet is equipped with temperature/smoke detectors that work in conjunction with the fire extinguishing device to automatically trigger extinguishing fires, reducing human intervention delays and minimizing fire losses.

4.Deployment of online monitoring and early warning systems

Early warning is a crucial part of fire prevention. Integrated online monitoring system for real-time monitoring of key parameters inside the cabinet:

- Temperature monitoring: Using fiber optic temperature measurement or infrared thermal imaging technology to continuously measure the temperature of busbar joints and circuit breaker contacts, and emitting audible and visual alarms when the temperature exceeds the threshold (e.g., 120°C);

- Gas monitoring: detects characteristic gases inside cabinets such as carbon monoxide and ozone (products of insulation aging or partial discharge), providing early warnings of potential faults.

Monitoring data is transmitted via IoT to the backend system, allowing operation and maintenance personnel to remotely monitor equipment status in real time, promptly handle abnormalities, and prevent fires.

5.Standardize Operation and Maintenance and Emergency Management

Operation and maintenance management is the line of defense to ensure the effectiveness of fire protection design. Establish regular maintenance procedures:

- Clean the dust inside cabinets quarterly (dust accumulation can easily lead to insulation degradation);

- Annually inspect the aging of insulation components and the tightness of cable joints (to prevent poor contact and heat);

- Test the effectiveness of fire extinguishing devices every six months.

At the same time, fire prevention training for operations and maintenance personnel is provided to help them master fire emergency procedures, such as power-off procedures during a fire and methods for manually activating extinguishing devices, thereby enhancing emergency response capabilities.

Conclusion

Fire protection design is a systematic project to improve the reliability of high-voltage switchgear sets, requiring coordinated efforts across materials, structure, fire extinguishing, monitoring, and operation and maintenance. Through these measures, the probability of fire can be effectively reduced, accident losses minimized, and the stable operation of high-voltage switchgear ensured, providing strong support for the safety and reliability of the power system.