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Keeping Machines Dry
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 …
Medium-Voltage Cable Testing and the Importance of Processes
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 …
Laws of Relay Testing
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 …
NFPA 70B: The Resurgence of the Electrical Maintenance Program
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 …
Catastrophic Generation Event Analysis
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. …
Unraveling the Mystery of Baffling Transformer Trips
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) …
Using Thermographic Surveys to Monitor Condition
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 …
Medium-Voltage Cable Installation Issues
Properly installed and maintained medium-voltage cable is highly reliable, and when properly installed, there is little or no maintenance to be performed. Yes, you should keep the terminations clean, and yes, you can perform a periodic VLF with tan delta or partial discharge test to trend degradation over the years. However, in my experience, the No. 1 reason cables fail …
DC Battery Systems
Electrical power systems, regardless of the industry (utility substations, industrial metal-clad switchgear, hospitals, data centers), are built with crucial auxiliary systems. These systems are dependent on each other to ensure these power users have electrical systems that are safe and reliable. The DC battery system might be one of the more critical of these systems. DC batteries provide power to …
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