High and low voltage switchgear is essential equipment in power systems, widely used in factories, buildings, substations, and other locations. However, during actual operation, due to environmental factors, operation methods, maintenance issues, etc., switchgear may experience various problems. Understanding these common issues helps in early prevention and timely resolution, ensuring the safe and stable operation of the power system. Based on industry experience, Xinhong Electrical summarizes the typical problems encountered during the use of high and low voltage switchgear.
Current-carrying components inside the switchgear (such as circuit breaker contacts, busbar connections, and cable joints) may experience abnormal heating due to poor contact, overload, or loose connections over long-term operation. Excessive temperature rise accelerates insulation aging and may lead to short circuits or even fires in severe cases.
Common causes:
Loose connection bolts
Oxidized or dust-covered contact surfaces
Long-term overload operation
Poor ventilation and heat dissipation
High and low voltage switchgear contains many insulating parts (such as insulators, bushings, and insulation boards). In humid, dirty, or overvoltage conditions, insulation performance gradually degrades, potentially causing flashover or breakdown.
Typical signs:
Discharge noise inside the cabinet
Carbonized traces on insulating surfaces
Failure during withstand voltage testing
High-risk scenarios: high temperature and high humidity environments, heavy dust workshops, coastal salt-fog areas.
Circuit breakers, disconnectors, and earthing switches in switchgear rely on operating mechanisms (spring, electromagnetic, or manual) for opening and closing. Over time, these mechanisms may jam, fail to reach proper positions, or refuse to operate.
Common faults:
Poor lubrication or corrosion of the operating mechanism
Worn or deformed latches
Malfunctioning auxiliary switches
Fatigue fracture of charging springs
To prevent incorrect operation, high and low voltage switchgear is usually equipped with mechanical or electrical interlocks (e.g., preventing operation of disconnectors under load, preventing access to live compartments). Interlock failure creates serious safety hazards.
Typical issues:
Deformed or stuck interlock rods
Damaged limit switches
Signal loss due to loose wiring
Secondary circuits are responsible for control, protection, signalling, and measurement functions. Loose terminal blocks, sticky relay contacts, and damaged cable insulation can lead to protection refusal or maloperation.
Common symptoms:
Burned opening/closing coils
Abnormal indicator light status
Protection device shows "control circuit open" signal
When switchgear is installed outdoors or in semi-open areas with insufficient ingress protection, water ingress, dust accumulation, or small animal intrusion may occur. For example, condensation causes metal corrosion; insects entering can cause phase-to-phase short circuits.
Recommended countermeasures:
Select appropriate protection rating (e.g., IP4X or higher)
Install heating and dehumidification devices
Seal cable entry holes
Many users focus on "use rather than maintenance", failing to perform regular cleaning, tightening, and testing, allowing minor issues to accumulate into major failures. Xinhong Electricalrecommends:
Perform power-off cleaning and tightening at least once a year
Test insulation resistance and loop resistance every three years
Regularly check the smooth operation of the operating mechanism
The reliability of high and low voltage switchgear directly affects power supply safety. By identifying common problems such as temperature rise, insulation, mechanical, interlock, and secondary circuit issues, and establishing a scientific operation and maintenance system, the failure rate can be significantly reduced. For professional high and low voltage switchgear product selection, retrofitting, or maintenance services, please contact Xinhong Electrical – your partner for safe and efficient power solutions.
