- Hi potential testing of cables, switchgear, is done as an acceptance test for new installations and a maintenance test for existing installations.
- This test is performed with dc voltage and provides the verification of the cable dielectric integrity, splices and joints. It identifies weaknesses and charts the gradual deterioration over the years.
- The dc voltage tests conducted on cables include insulation resistance measurement and dc high potential test. We can go as high 170kv dc with our unit. A dc high voltage test provides accurate leakage current data whereas an ac high potential test is only a pass or fail test with little additional information.
- The insulation resistance measurement test uses a dc voltage source of at least 2500v that gives insulation readings in megohms. This method gives an initial indication of the cable insulation.
- The tests are segregated into two groups. An acceptance proof test on brand new cables and maintenance proof test on older cables.
- A thermography survey, also called an Infrared scan, detects heat rises in equipment while it is operating.
- Excessive heat is the leading cause of electrical equipment failure. A thermography survey or as more commonly called, infrared inspection, can help to locate trouble spots quickly. It can be done while the equipment is operating, detecting the smallest temperature change, prior to an unscheduled outage.
- Infrared inspection is recommended by insurance companies. It is recommended to be performed at least annually.
- The inspection is done using a real time thermal imager, which allows experienced operators to scan quickly many pieces of equipment.
- This lets us identify problem areas with a high resolution image. Further it allows you to prioritize your maintenance to focus on problems that have a direct effect on your equipment.
- There’s no contact between the camera and the equipment being scanned.
- Equipment routinely scanned by this method are, power panels, circuit breakers, substations, transformers, switches, fuses and more.
- With early detection of potential electrical problems, it can result in economic savings from reduced equipment failure and costly downtime.
- Electrical equipment deteriorates. It is normal, but it doesn’t have to lead to failure.
- An effective substation maintenance program identifies factors leading to deteoration and provides measures for reversing the effects.
- It can prevent downtime by minimizing breakdowns and will extend the life of the equipment.
- In addition insurance companies now require preventive substation maintenance as part of risk management.
- Power Works Electrical Services staff is experienced in all facets of substation maintenance.