An electrical switchgear is the centralised collection of switches, fuses, and circuit breakers whose primary function is to control, isolate, and protect electrical equipment. It is usually found throughout electric utility transmission and distribution systems as well as in industrial and commercial facilities. The switchgear is an integral part of these systems. Therefore, its failure can result in significant disruption.
Apart from disrupting the production, transmission, distribution, or conversion of power, switchgear failure may also lead to dangerous accidents. The common hazards associated with switchgear failure include electric shock, explosions, and fire.
There are several possible reasons why a switchgear may fail. Below are the common causes of switchgear failure to take note of.
1. Faulty Connections
Faulty or loose connections in the switchgear can increase resistance, which usually increases the heat. The increase in heat will then escalate until the connection or nearby insulation completely fails and results in a fault. According to estimates, around 25% of all electrical failures occur because of loose connections.
In order to avoid switchgear failure due to faulty connections, infrared inspections of the switchgear should be performed regularly. Your switchgear should have viewing ports that can also pass ultraviolet light for cameras to be used in inspecting corona and surface partial discharge.
2. Water Intrusion
During natural disasters or accidents, water intrusion or immersion can create instant short circuits, long-term corrosion of metallic components, damage the insulation, and several other complications.
Voltage stresses, in particular, may damage the hydrophobic insulation surfaces intended to prevent moisture absorption and may thus cause a medium-voltage switchgear exposed to high humidity to absorb moisture. To avoid any moist-related insulation faults that may result in the long run, using a partial discharge detector or an infrared camera to spot unusual heating of corroded connections is recommended.
3. Breaker Racking
Racking refers to the act of connecting or disconnecting a circuit breaker to an electrical bus inside the switchgear. Professional electric engineers usually perform it since it is often considered a hazardous action. Racking in a closed circuit breaker onto an energised bus may result in immediate and severe damage to equipment or even cause personal injury or death.
To avoid these enormous risks, always ensure that the electrical and mechanical interlocks in your switchgear are functional and that all the breaker and cell components are inspected and serviced correctly. Personnel safety should also be ensured at all times.
4. Insulation Breakdown
This type of switchgear failure comes in a variety, depending on the voltage insulation. Low-voltage insulation is not usually subject to the same voltage stresses as medium-voltage insulation because of its fair simplicity. Thus, maintaining low-voltage insulation mainly involves just keeping the insulation dry and clean.
On the other hand, medium-voltage insulation systems are considered much more complicated due to more significant voltage stresses. Overstressed areas within the switchgear will initially fail over small portions of the insulation but will compound over time until a complete failure occurs. The solution to preventing such a failure starts with utilising a hand-held partial discharge detector that can detect surface as well as internal insulation defects.
Conclusion
Switchgear failures are something that should be constantly watched out for. Just like the winding in an electric motor, the switchgear may fail due to various reasons, including loose connections, water intrusion, breaker racking, and insulation breakdown. To prevent total failure of your switchgear, proper maintenance and regular inspections by a professional are recommended.
There are several reputable electrical and engineering companies you can trust with your switchgear in Singapore. These companies provide reliable switchgear installation and inspection as well as other essential services, such as generator overhauling, transformer maintenance, and motor rewinding. Consulting these professionals immediately whenever your switchgear fails is highly advised.
