Medium Voltage Switchgear now Safer than ever
As most electrical engineers know, working with switchgear carries with it potential hazards. Improvements in design and better working practices, however, have contrived to make it much safer than it used to be.
If it were an animal, switchgear would be a champion racehorse; highly-strung, unpredictable – and with a powerful bite. But as every champion jockey will tell you: it’s all in the training. If you know what you’re doing and have thorough and appropriate training, you should be able to handle switchgear, no problem. If you are a novice, however, take every precaution and wear all the safety gear you can.
An accident associated with switchgear has been arc flash. These can occur when a large electrical current passes through ionised air and can be triggered when a circuit-breaker fails or when insulation has been seriously compromised. Although rare, these accidents have had serious consequences in the past. When an arc flash occurs, the temperature surrounding it can rise to around 20,000 degrees centigrade, which vaporises conductors leading to an explosion and the release of globules of molten metal. Anyone nearby could be in danger of serious injury or death.
Arc flash can also cause fire, the production of dangerous gasses and the leakage of burning oil in older designs such as oil insulated switchgear.
The good news is that modern designs of switchgear have moulded insulation, which allows good control over electric fields thereby reducing the susceptibility of the insulation to break down. It significantly reduces the chances of arc-related faults. It won’t entirely negate such incidents, or the chances there of, so it is important still to observe appropriate safety information and practices.
Not quite so hazardous but potentially more disruptive is the problem of partial discharge in insulation, which is a common cause of unreliability in MV switchgear. Here, small currents in the form of sparks can leak through the insulation at points where it has deteriorated. In hazardous environments, this could cause ignition of flammable materials but at best it could lead to breakdown of equipment and expensive repair. Needless to say, the best remedy for this is regular testing and inspection of switchgear, including all cabling and connectors.
When you choose Riello UPS for switchgear supply, you can be sure of our expertise. We always design switchgear into the system from the start and our name appears on the panel so you can rest assured we make sure that the quality of our work is consistent with the rest of your UPS and standby power installation.
