The 2023 edition of NFPA 70B saw it converted from a recommended practice to the Standard for Electrical Equipment Maintenance. This NFPA 70B update will continue to work in conjunction with ANSI/NETA standards and other NFPA standards to provide details on power system maintenance to NETA companies and NETA technicians. 1. Which option does NFPA 70B define as “a …
The purpose of using temporary protective grounds is to protect personnel servicing the equipment and to create a safe work environment. Before servicing a piece of electrical equipment, it is important to ensure that it is in a safe state and to verify zero voltage before applying temporary protective grounds. In many situations, more than one set of grounds or …
This article demonstrates how current transformer (CT) saturation can adversely affect transformer differential protection and how to easily mitigate its effects via inbuilt relay functions. We provide calculations and simulation for a three-phase fault on the low side of the transformer just external to the CTs. APPLICATION The application is for a three-phase delta-wye connected transformer serving station at a …
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 …
Commissioning and maintenance procedures for low-voltage circuit breakers may include testing to determine whether the circuit breaker is able to respond correctly to faults or overload conditions as specified in the coordination study. This requirement may include ground fault (GF) as part of the protection scheme. Testing may be performed through primary or secondary injection; primary injection is the best …
Communication plays a critical role in the operation of modern substations. As the industry was evolving into the digital age, there was a need for a unified communication architecture, and the International Electrotechnical Commission (IEC) began to develop international standards for communication. In this quiz, we will explore the international communication standard IEC 61850. 1. What is the international standard …
It is said that spring is a time of new growth for Mother Nature, but it is also true for many man-made industries. It can be a time of heavy workload, especially for construction and related industries. Each season presents very real hazards that everyone must be made aware of. It is a good idea to train employees about these …
A numerical feeder protection relay would trip when a collector feeder breaker is closed due to inrush at a solar photovoltaic site. The inrush current is due to energizing power transformers. This article demonstrates how to use harmonic blocking to prevent this unwanted tripping. Magnetizing inrush currents may cause overcurrent elements to operate when the line is energized. The fundamental …
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. …
As advancements in technology have driven the world over the past 20 years, the ability to protect and control our electrical infrastructure has advanced as well. By implementing advanced technologies and innovative solutions, the grid has undergone a significant transformation, accommodating the growing demands of an increasingly digital and interconnected world. The enhanced visibility and automation have improved grid resilience, …