No good electrical testing field story starts with “everything went perfectly.” Inevitably, things do not go according to plan. Breakers of all types, makes, and models are the source of great stories and hard lessons learned under pressure to get a circuit back in service. The purpose of this article is to share common issues that fall into a few …
Electrical insulation is designed to keep current from flowing where it shouldn’t. Insulation integrity is therefore critical and is assessed via a battery of tests. Many things can compromise the results of these tests, including temperature, humidity, erroneous test procedures, etc. Previously, I wrote about the effects of humidity on insulation integrity tests. This time I focus on erroneous test …
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Equipment underutilization is, by implication, an underdiscussed subject. I am all too familiar with this phenomenon, e.g., relays with useful but unprogrammed protective functions, calibrated test equipment that rarely sees the light of day, fully functional battery chargers next to pallets of long-deceased 12 V valve-regulated lead–acid batteries (VRLAs), etc. This negligence is no less true of rotating machines, where inexpensive …
In a previous article, I discussed the challenges and the importance of proper cable installation. Here, we turn our attention to the challenges of obtaining accurate test results. These best practices and processes come with a field technician’s ability to be efficient and confident in their test results. I have been around the industry long enough to be present for …
Relay testing has long been one of the more technically demanding and complicated aspects of the business of electrical acceptance and maintenance testing. The plethora of skills required to be an excellent relay technician includes (in no particular order) electrical theory, power system design, AC and DC control drawing interpretation, and the ability to simulate power system faults to name …
Numerous articles have been written about NFPA 70B in recent months following the recommended practice becoming a standard. All this chatter and renewed interest is coming from the perception — and rightfully so — that failure to perform minimum electrical maintenance could lead to OSHA fines. I’d like to believe that facilities that did not previously have an electrical maintenance …
A major event occurred at a large power plant in the southwest region. A new generator circuit breaker (GCB) had been installed for a combined cycle power block (CCPB) consisting of a gas turbine generator (CTG) and a steam turbine generator (STG). The new GCB is located on the low side of the generator step-up transformer (GSU) serving the CTG. …
Modern substation control and communication have revolutionized the ability to troubleshoot system faults and mis-operations. Event fault records and documenting every input and output provide invaluable information to help answer the question, “What happened?” However, there are hundreds of thousands of systems with legacy equipment. These systems can present seemingly baffling challenges that could necessitate several attempts (test and try) …
The most basic maintenance begins with our senses. Electrical and mechanical equipment tend to produce distinct sights, sounds, or smells before it fails. However, our senses have strict limitations. BACK TO SCIENCE CLASS Anything above zero kelvin will produce infrared radiation. There is no molecular movement at 0 K, including electron movement. When electrons move back into inner atomic orbitals (which …