Rapid photovoltaic (PV) penetration into the electric grid has mandated deeper operational and technical understanding of protection schemes in PV farms. An effective protection scheme ensures a grid-connected system functions reliably and securely, and testing and commissioning the entire protection scheme to prove its operational success is of paramount importance. This article presents a standard grid-tie photovoltaic farm architecture and …
First, let’s look at some industry-accepted definitions to establish context. Low voltage is anything below 1 kV. The common building-wiring voltages are 120, 240, 480, and 600 V. To the uninitiated, this can seem confusing and even ridiculous. Get across 600 V, and it can fry you like bacon, but in industry parlance, it is still low voltage. Put into …
Cable testing is one of the oldest forms of testing in the industry. At first, cables were tested using DC voltages, but this was found to damage newer cable types, so additional cable testing methods were developed. This issue’s Tech Quiz takes a look at cable testing. 1. During the early years of cable testing, which two primary types of …
Many regulatory agencies direct which documents are required to perform a company’s tasks. In some cases, federal and state requirements must be adhered to for the same task or hazard. For example, the United States Environmental Protection Agency (US EPA) and state environmental agencies, such as the Massachusetts Department of Environmental Protection (MA DEP), regulate potential environmental impacts that may …
May 2020 was a difficult month for our nation, and 2020 is certainly shaping up to be a difficult year. As essential service providers, many in our industry were called upon to maintain or continue building the nation’s infrastructure. We all understand and appreciate that hospitals, emergency services, government facilities, manufacturing, and even residences could not function without power, and …
This article demonstrates how CT saturation can adversely affect transformer differential protection and how to easily mitigate its effects via inbuilt relay functions. The solution is to 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 load …
In September 2020, the newest (2021) edition of NFPA 70E, Standard for Electrical Safety in the Workplace® will be available to the industry. So how is it that such an important safety standard, put forth as a national consensus document, is reviewed, revised, and improved every three years? We’ll look at the process a little later in this article. But …
Welcome to the fall edition of NETA World. In this issue, our authors cover the various methods for performing testing on medium-voltage cables. I recommend you start with the article by Tom Sandri of Shermco Industries, which lays out the current test methods for acceptance and maintenance testing of medium-voltage cables. Next, dive into the articles on specific testing methods …
Medium-voltage (MV) power cables are the backbone of the power distribution systems developed over two hundred years. Currently, 2.3 million miles of MV cables are installed in the USA, most with extruded insulation. Diagnostic testing technologies can differentiate MV cables by their operational condition and aging process prior to faults, thereby providing guidance for proactive maintenance and asset management. This …
John Hauck, 67, recently retired Electrical Technology Instructor at Long Beach City College (LBCC) and dear friend of NETA and Tony Demaria Electric, Inc. (TDE), passed away on May 31, 2020. John was actively involved in successfully implementing the NETA Electrical Power Testing Technician (EPTT) Curriculum into LBCC’s existing Electrical Technology Program. He worked diligently with NETA and TDE to …