Importance of Regular Intrusive Maintenance


We recently became involved in a job demonstrating once again the importance of regular intrusive maintenance.

Early on a Saturday morning back in the spring we received a call from an HV metered customer complaining of a partial loss of supply to his site; upon arrival the site engineer explained that they had not carried out any intrusive maintenance to their switchgear since the installation was commissioned some 15 years previously. Their logic was that the equipment was modern gas filled type and as such it was “maintenance free” and that as the substation fed site critical supplies they could not afford the down time. Our engineer explained the flaws in this logic and subsequent intrusive maintenance was planned in.

Upon an internal inspection our team discovered a partial discharge with L2 tracking to earth. We were able to draw on our switchgear stock and had a replacement unit despatched to site immediately, the unit being received on site some 90 minutes later. A new feeder cable needed to be jointed in, cable and joints being drawn direct from stock and within just a few hours the site was re energised.

EME Power Systems Contracting Engineer, James Grigg had this to say of the incident:

“It is remarkable how many times we hear that an area is too important to be switched off for maintenance, or that SF6 equipment doesn’t require it – these statements are flawed and illogical. If you have a critical area that you cannot afford to have without power then the only way to ensure this is to carry out maintenance work”.