Loading patent…
AssigneesClemson University Research Foundation, Duke Energy Carolinas, LLC
InventorsEdward Randolph Collins, Jr., Timothy Lee Smith, Randall J. Emanuel
Estimating the term…
Embodiments according to the present invention provide an Impedance-based Arc-Fault Determination Device (IADD) and method that, when attached to an electrical node on the power system and through observations on voltage, current and phase shift with a step load change, determine the effective Thevenin equivalent circuit or Norton equivalent circuit at the point of test. The device and method determine the expected bolted fault current at the test location of interest, which enables calculation of incident energy and the assignment of a flash-hazard risk category.
A test device comprised of:
A testing method comprising:
A computer program product for determining arc fault energy in an electrical power system, wherein the computer program product comprises at least one computer-readable storage medium having computer-readable program code portions stored therein, the computer-readable program code portions comprising:
A test device for determining fault incident energy available at an electrical node of an electrical power delivery system comprised of:
Dependencies are inferred from the claim text.
Drawings are temporarily unavailable. Open the PDF at USPTO
From the US filing history. Foreign family members aren’t listed.
Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant: measuring…
Using digital measurement techniques: arrangements for monitoring electric power systems, e.g. power lines or loads; Logging
Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections: testing…
Measuring electric variables
About 1 year 5 months of term left · ends 19 Mar 2028 (estimated)
Between five and 10 times a day, an arc flash explosion occurs in electric equipment in the United States that sends a burn victim to a special burn center, according to statistics compiled by CapSchell, Inc., a Chicago-based research and consulting firm that specializes in preventing workplace injuries and deaths.
In response to these statistics and the obvious detrimental affects of arc fault incidents on workers, in the United States the Occupational Safety and Health Administration (OSHA) has begun enforcing recommendations by the National Electric Code (NEC) and National Fire Protection Association (NFPA) regarding employee safety procedures when work on energized systems must be performed. Admittedly, it is preferable and mandated that, when possible and practical, electrical systems are to be worked on in a zero energy state (ZES). However, this condition does not exist under all circumstances and sometimes work on energized systems is necessary.
The 2000 release of the NFPA's 70E document, incorporated herein by reference, recommended the use of personal protective equipment (PPE) based on the potential for exposure to heat energy radiated by electric arcs. NFPA 70E specifies the need for proper personal protective equipment (PPE), in all conditions where there is a possibility of harm induced due to electrical arcing. Previously, electric shock was thought to be the primary and most frequent type of injury sustained when working with electrical systems. A recent study conducted by the National Institute for Occupational Safety and Health on injuries sustained during work with electrical components points to the fact that a significant portion, approximately 40 percent, of these injuries were due to arc flash; an arc flash exposure may result in severe burns to the skin and, in some cases, death.
The accompanying drawings, not drawn to scale, which are incorporated in and constitute a part of this specification, illustrate embodiments and together with the description, serve to explain the principles of the methods and systems:
FIG. 1A shows a typical electrical system with a single point of generation and four loads drawing current with specified magnitude and power factor, and computed voltages at Busses 1 and 2;
FIG. 1B shows the addition of another load to FIG. 1A, in this case the addition of the IADD device at Buss 2, according to an embodiment of the present invention, that draws current at a unity power factor and effects both the voltage magnitude and phase angle at Busses 1 and 2;
Before the present methods and systems are disclosed and described, it is to be understood that the methods and systems are not limited to specific synthetic methods, specific components, or to particular compositions, as such may, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting.
Definitions
As used in the specification and the appended claims, the singular forms “a,” “an” and “the” include plural referents unless the context clearly dictates otherwise. Ranges may be expressed herein as from “about” one particular value, and/or to “about” another particular value. When such a range is expressed, another embodiment includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms another embodiment. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint.