Preventing Overheating in MV Switchgear

In utility, commercial, and industrial networks, MV Power Distribution switchgear is essential to the safe distribution of electricity. Qinghang Electric Co., Ltd. manufactures reliable MV switchgear designed to handle heavy electrical loads. However, even the ideal-designed switchgear, including SF6 RMU configurations, can face overheating issues if operational and environmental factors are not properly managed. Understanding the causes of overheating and implementing preventive measures is essential for maintaining system efficiency and prolonging equipment life.

Overheating in MV switchgear can cause equipment failures, unplanned downtime, and even safety hazards. SF6 RMUs, while designed to withstand high electrical stress, are not immune to thermal stress, especially under sustained high loads or in challenging environmental conditions. Addressing overheating proactively can save time, costs, and improve overall operational reliability.

Causes of Overheating in MV Switchgear

Excessive Electrical Load

Operating MV switchgear beyond its rated capacity can generate excessive heat. Continuous overcurrent conditions stress both the conductors and insulation materials, increasing the risk of thermal degradation.

Poor Ventilation and Airflow

Insufficient airflow around switchgear cabinets traps heat, reducing the efficiency of heat dissipation. Switchgear rooms with inadequate ventilation or blocked air vents are particularly vulnerable to overheating.

Component Deterioration

Worn-out contacts, aging insulation, and failing circuit breakers can create resistance points where heat accumulates. In SF6 RMUs, damaged gas seals can also reduce cooling efficiency, contributing to elevated temperatures.

Environmental Factors

High ambient temperatures, humidity, and dust accumulation can accelerate thermal stress. Outdoor installations without protective shading or cooling can experience faster wear and higher internal temperatures.

Electrical Transients and Faults

Short circuits or repeated switching operations generate transient heat spikes. These transient events may not immediately damage components but can cumulatively cause overheating over time.

Signs of Overheating

Operators should monitor for the following indicators:

Discoloration or melting of insulation materials.

Unusual odors (burnt or ozone-like smells from SF6 gas).

Unexpected tripping of breakers or relays.

Increased temperature readings on thermal sensors or infrared scans.

Preventive Measures

Load Management

Ensure that switchgear operates within its rated load limits.

Distribute electrical loads evenly across phases to prevent localized hotspots.

Environmental Controls

Maintain proper ventilation in switchgear rooms.

Consider installing air conditioning or forced-air cooling in high-temperature areas.

Use dust filters and maintain clean environments to prevent insulation degradation.

Routine Inspections and Monitoring

Conduct regular infrared thermography inspections to detect hotspots early.

Implement continuous temperature and SF6 gas pressure monitoring in RMUs.

Check connections, contacts, and circuit breakers for signs of wear or corrosion.

Component Upgrades

Replace aging contacts, insulation, and breakers proactively.

Qinghang’s MV switchgear line includes modular designs that allow easy replacement and maintenance, minimizing downtime.

Operator Training

Educate personnel to recognize early warning signs of overheating.

Provide clear procedures for emergency shutdown and load reduction.

Case Study: Successful Overheating Prevention

A manufacturing plant operating a Qinghang MV switchgear and SF6 RMU system faced recurring temperature spikes during peak production hours. By installing additional ventilation, performing quarterly infrared inspections, and implementing load balancing, the plant reduced internal switchgear temperatures by 20%. This proactive approach not only extended equipment life but also prevented costly unplanned outages.

By understanding the root causes, implementing proper preventive measures, and leveraging Qinghang’s reliable switchgear solutions, operators can ensure stable, safe, and efficient electrical distribution.