Causes of Switchgear Failure and How to Avoid Them

Switchgear Failure Causes An electrical switchgear is a centralised conglomeration of…

Switchgear Failure Causes

12KV XGN15 high voltage switchgear

An electrical switchgear is a centralised conglomeration of switches, fuses and circuit breakers used to control, separate and secure electrical equipment.

This kind of set-up is normally found in electric utility transmission and power distribution systems, as well as in industrial and commercial locations. The switchgear is an indispensable component of these systems, so any breakdown can cause considerable disturbances.

Apart from hindering the generation, transmission, circulation, or transformation of power, switchgear breakdown can also provoke hazardous mishaps. The typical risks associated with switchgear malfunction consist of electric shock, blasts, and conflagration.

There are a number of common causes for why a switchgear may not operate as intended. Here are the prevalent sources of types of faults to be aware of:

1. Insulation Breakdown

Insulation breakdown is an important safety concern in any electrical system. In switchgear, insulation is used to reduce the risk of electrocution and prevent voltage stresses from causing a short circuit. Insulation can fail due to age, moisture or other environmental factors.

At medium-voltage levels, the insulation may be subject to the same stresses of the voltage as high-voltage systems. So it’s important to keep it dry and clean. Areas within the switchgear that are especially vulnerable include bus connectors, control wiring and motor leads.

When insulation breaks down, current flow can increase and cause a complete failure of the switchgear. Proper maintenance of all areas is essential for keeping insulation dry and free from debris which contributes to breakdowns over time.

2. Faulty Connections

switchgear manufacturer

Faulty connections in switchgear can be a major cause of electrical failures. They can increase the heat in the switchgear and reduce the insulation leading to faults and even switchgear failure.

It is important to avoid switchgear failure due to incorrect connections by carrying out infrared inspections. Infrared inspections detect heat that is generated by incorrect connections and other problems allowing for them to be identified quickly before they become a major problem.

In order to ensure that switchgear does not fail due to incorrect connections, regular infrared testings should be carried out as part of an overall maintenance plan. This will help to prevent electrical failures occurring due to incorrect connections and reduce the risk of switchgear failure.

3. Water Intrusion

In the event of a natural catastrophe or incident, water seepage or submersion can lead to immediate electrical breakdowns, long-term rusting of metallic elements, impair the protective covering, and cause numerous other issues.

The hydrophobic insulation surfaces of medium voltage switchgear ( mv switchgear ) exposed to high humidity can be damaged by voltage stresses. Which could lead to absorption of moisture and eventual insulation faults. To prevent such problems in the future, it is recommended to use a partial discharge detector or an infrared camera to detect heated connections corroded by moisture.

4. 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.

switchgear internal structure

Switchgear Failure Mode

A malfunctioning Isolation Bushing, caused by a filthy bushing, worn out mechanical breaker. And damaged seal breaker resulting in a reduced isolation resistance and shorter bushing lifespan. To avoid such a situation, it is advised to carry out Partial Discharge Check, Visual Inspection, Clean Isolation Bushing, Voltage Verification Test, and Isolation Bushing Replacement if needed.

Avoiding Switchgear Failure

Switchgear is a key component of any electrical power system and its failure can cause serious problems. To avoid switchgear failure, it is important to keep the switchgear assembly in good condition with a maintenance program that includes regular examinations. This will help ensure the switchgear components are working efficiently and reduce the risk of faults and other causes of failure.

As part of this maintenance program, all components should be inspected regularly including fuses and circuit breakers. If any faults or causes of failure are identified during these examinations, they should be addressed immediately.

Additionally, an annual switchgear maintenance program should be implemented to further reduce the risk of failure. This should include testing all parts for proper operation and making repairs as necessary.

12KV HXGN series switchgear

By implementing a comprehensive examination and maintenance program for your switchgear assembly, you can help avoid switchgear failure and protect your power system from potential damage or disruption.

Conclusion

Metal-clad 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 examinations by a professional are recommended.

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