Steel processing requires a lot of energy and powerful electrical systems. However, a single electrical component failure can bring steel production to a halt, resulting in significant time and financial losses for manufacturers.
The more severe the failure, the longer it takes to restore systems. To predict electrical component failures in all systems, including substations, MCC gear, transformers, etc.; maintenance teams use condition monitoring technologies like ultrasound inspection.
The earlier an issue is identified, the more time there is to schedule maintenance. Because it is significantly less expensive and a far better alternative for everyone, electrical repair technicians prefer to do repairs on their own terms rather than on the terms of the machine. Early detection of a system’s need for attention also ensures that the required maintenance is “simple maintenance,” rather than a costly overhaul, entire repair, and/or replacement. Simple maintenance refers to routine cleaning, dusting, and minor component replacement with readily available spare parts.
Partial discharge is the cause of the majority of electrical failures
Partial discharge is defined as “a localized electrical discharge in an insulation system that does not completely bridge the electrodes”. A discharge can be phase to phase or phase to ground and is referred to as an “arc” or “spark.” Partial discharge is destructive to the conductor or insulator, and over time, will cause the component to fail. Corrosive gases, such as nitrous oxide, have a deleterious impact on insulator integrity.
The system voltage, the form of the void from phase to phase, the ambient temperature, the state of the insulation material, and the environmental variables such as pollution and humidity, all influence partial discharge. The time it takes for a system component to fail is influenced by the combination of these factors. Partial discharge is a common issue in high-voltage switchgear, but it can also be an issue in low-voltage switchgear. Since voltage is an influencing factor, the higher the voltage the more destructive partial discharge becomes.
One stage of partial discharge is termed “Tracking”
Because there is no evidence of heat build-up, tracking is difficult to detect. It can be considered arcing in its early phases. Tracking, like corona discharge and arcing, exists solely to find a path to the earth. Dirt, dust, and moisture help tracking follow this path, which is why simple maintenance like cleaning is effective in prolonging the service life of electrical systems diagnosed with tracking. The buzzing and crackling that marks the start of tracking rises in intensity until it reaches the point of flashover. After flashover occurs it becomes quiet again. It is this constant build up in intensity and discharge that leads to insulator breakdown and graduation to more destructive arcing.
Watch the video below to better understand the different kind of electrical faults and how you can hear them through an SDT340.