In this paper, we share the experiences of designing, installing, and commissioning grounding and ground fault protection systems for several different low-voltage and medium-voltage power systems. The diversity in design of low-voltage power systems, the limitations of inverters, and the requirements of the National Electric Code are explained.
This paper examines the performance of traditional phasor-based protection and new time-domain elements in short line applications. Protection elements on short lines are ranked from best to worst, and solutions to common problems are presented.
This paper addresses how to protect an adjustable speed drive installation by breaking the application down into specific components: motor, drive, input mechanism, and feeder. The paper provides a brief background on the advantages and classifications of adjustable speed drives, followed by an overview of considerations for protecting adjustable speed drive feeders at different voltage levels. A real-world adjustable feed drive application fed from a high-voltage source is analyzed. Best design practices for selecting protection parameters are also shared.
This paper presents a case study for a fast and reliable load-shedding scheme (LSS) implemented for one of the largest North American wastewater treatment plants. It highlights the details of LSS algorithms, implementation details, and testing scenarios showing the advantages of deploying the fast LSS.
In this paper, we propose a comprehensive and cost-effective approach to solving protection challenges for complex distribution and subtransmission feeders, including power line-caused wildfires, high-impedance faults, downed conductors, distributed energy resources, and microgrids. Our method uses transmission-grade protection principles made possible through a novel technology of measuring currents and voltages at locations distributed along the feeder without introducing active electronics outside of the substation fence. By allowing instantaneous current and voltage measurements from the feeder, we dramatically simplify and improve protection and control applications. In our approach, feeder protection becomes fast and sensitive and far more selective compared with today’s practice, dramatically reducing wildfire and public safety risks.
This paper presents challenges and solutions to 87L applications in systems with IBRs. The solutions can be used for all 87L applications, but they significantly benefit IBR applications, series-compensated lines, evolving faults, and single-phase tripping applications.
When an overhead distribution conductor breaks and the energized wire falls on the ground, it often creates a high-impedance ground fault, which may be difficult or nearly impossible to detect by traditional protective equipment in the substation. This condition presents wildfire risks and public safety hazard. The falling conductor protection solution, based on synchrophasor technology and IEC 61850 Generic Object-Oriented Substation Event (GOOSE), detects and trips the affected circuit section within milliseconds of the break – before the energized conductor falls on the ground.This paper, jointly written by San Diego Gas & Electric Company (SEDG&E) and SEL, discusses the first-of-its-kind Falling Conductor Protection solution implemented on a 12 kV rural distribution circuit with a private Long-Term Evolution (PLTE) network.
Eversource Energy deployed a 38 MWh battery energy storage system (BESS) in Provincetown, MA to improve the power reliability on the outer Cape Cod region.The BESS inverters are operated in grid-forming mode during grid-parallel operation to facilitate seamless islanding and seamless restoration.This paper provides an overview of the project, challenges encountered in designing the protection and control schemes, and the innovative solutions used to address these challenges.
This paper investigates time-domain metering approaches and references measurements of a 345 kV transmission line. A new power quality metric, “electric energy factor,” is introduced as an alternative to power factor utilization measurement under distorted conditions.
This paper discusses considerations that a protection engineer must evaluate for a line current differential protection scheme when applying GNSS (Global Navigation Satellite Systems) for data alignment. Time-synchronization protocols, such as IRIG-B, IEEE C37.118, IEEE 1588 Precision Time Protocol (PTP), and the distribution of the time signal must be applied using the best practices, as discussed in this paper, to ensure a robust and secure design. Commissioning tips are also provided to help guide successful implementation of time into the various protection schemes. Finally, the paper presents four cases highlighting line current differential and DSS-based applications where an improper time-source configuration led to undesired behavior of the protection scheme. These cases focus on the time-source installations and how the time-source configuration led to the undesired behavior.
This paper provides further application experience, event analysis, and lessons learned from PPL Electric Utilities use of an HIF algorithm to detect and isolate high-impedance faults.
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