Designing, installing, and maintaining an adequate grounding system is as important a part of substation design and maintenance as any other. “Out of sight, out of mind” definitely does not apply here. The grounding grid is not only essential to proper function and power quality but is also critically important to worker safety as well as that of public passersby. …
Current protection testing practice is the result of history, custom, and seemingly conflicting motivations. Despite dramatic advances in protection system technology, protection testing philosophy and practice have not kept pace. This article reviews past and present protection testing practices and explores ways the industry could evolve to meet current and future challenges. As it was in the very beginning, the …
Roger Grylls, CET, is a Senior Consultant with Magna IV Engineering Inc. in Edmonton, Alberta, Canada. In his current position, he works with the sales team to provide solutions for the electrical needs of the company’s clients. Grylls graduated from the Northern Alberta Institute of Technology (NAIT) electrical engineering technology program in 1997 and joined the company as a new …
An out-of-phase synchronization (OOPS) event results in a torque transient on the generator and prime mover. It exposes the generator, generator step-up (GSU) transformer, and system elements to a current transient that puts mechanical and thermal stresses on windings and other conductors. These transients can be significant and result in through-current magnitude equivalent to a three-phase fault located at the …
As large commercial and industrial construction ramped up in the 1990s and the size of facilities grew, electrical distribution transitioned from low voltage (480 volts and below) to medium voltage (12–15 kV). These design changes brought about the need for more sophisticated electrical distribution protection, which coincided with the early generations of electronic protective relays, including the widely employed GE Multilin …
Testing plays a critical role in verifying that the protection scheme is designed to meet its intended purpose. It ensures that the wiring diagrams match the schematics, and everything works together seamlessly. WHY DO WE TEST? While engineers and electricians are highly skilled professionals, they are human and can make mistakes. That’s why, during the commissioning process, we meticulously search …
When a generator owner plans site upgrades that result in protection setting or coordination changes, compliance with several North American Electric Reliability Corporation (NERC) Reliability Standards such as PRC-019, PRC-024, PRC-025, PRC-026, PRC-027, MOD-025, and MOD-026 will be impacted, depending on the scope of the upgrade. However, the effort to maintain compliance — and equally important, maintain compliance documentation — …
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 …
First published in 1979, NFPA 70E, Standard for Electrical Safety in the Workplace, has evolved tremendously over the years and is arguably the premier electrical safety work practices standard available to the electrical worker. The current 2024 edition is 113 pages, three chapters, and 19 Informative Annex sections. Many sources of information and safety knowledge are embedded in these pages, …
Protective relays are critical power systems components, and it is essential to design and use them properly to detect power system issues. As NETA-certified technicians, we must be familiar with the purpose and operation of various types of protective relays. 1. Which type of relay was the earliest design for protective relaying? a. Interconnector relay b. Electromechanical relay c. Static …