Technical publications by Jim Phipps
Power Transfer to Imbalanced Arcing Faults
Abstract:
This paper presents a method for calculating arc current and power transfer to imbalanced arcing faults in three phase power systems using equations based on a balanced single phase equivalent circuit. Power transfer to imbalanced three-phase faults is compared to a balanced case for a 13.2 kV power system to illustrate the use of the equations presented.
Co-authors:
D.R. Clark, J.K. Phipps
Publications:
https://www.academia.edu/44936431
Factors Affecting Arc Flash Hazard
Abstract:
This paper discusses maximum arc power and how it is dependent on transformer size and per-unit impedance for low and medium voltage systems. An approximation for arc power is given and compared to the exact value to highlight differences. Arc length is discussed in relation to maximum power transfer and an expression for the arc power intensity as a function of distance from the arc is derived and compared to point source and infinite line source models to study how it attenuates with distance.
Co-authors:
D.R. Clark, J.K. Phipps
Publications:
https://www.academia.edu/44408353
A Formula for Arc Current Cutoff
Abstract:
This paper derives a formula for arc current cutoff as a function of circuit voltage, resistance, reactance, arc length, and arc voltage gradient. Formulas are also derived for cutoff current, expressed in per unit of bolted fault current, and corresponding arc length. These formulas and associated approximations are used to explore possible reasons for the discrepancy between an "industry accepted" 38% cutoff value and the 21% value of NFPA 70E-2003 for 480/277 volt systems.
Co-authors:
D.R. Clark, J.K. Phipps
Publications:
https://www.academia.edu/43963688
Arc Fault Equations and the Effect of Arc Length, Development and Discussion
Abstract:
This paper discusses electric power system arcing faults with emphasis on how arc current and arc power vary with arc length based on a non-linear arc resistance model. Maximum power transfer is shown to occur at an optimal arc length that is dependent on source voltage, x/r ratio, and arc voltage-gradient with arc length limits that are based on theoretical and empirical factors. Examples include plots of arc current, arc power and a comparison with IEEE Std. 1584-2002 for both medium-voltage and low-voltage systems.
Co-authors:
D.R. Clark, J.K. Phipps
Publications:
https://www.academia.edu/34663150
A Transfer Function Approach to Harmonic Filter Design
Abstract:
This paper details a new transfer function approach in passive harmonic filter design for industrial and commercial power system applications. Filter placement along with six common filter configurations are presented. Harmonic impedance, voltage division and current division transfer functions are derived and used in a practical filter design procedure which incorporates IEEE-519 distortion limits directly into the design and component specification process. A simple four step filter design procedure is outlined and used in a variable speed motor drive pumping plant application.
Author:
J.K. Phipps
Publications:
IEEE Applications Society, 42nd Annual, Petroleum and Chemical Industry Conference, Denver, Colorado, September, 1995. Paper No. PCIC-95-19.
http://ieeexplore.ieee.org/document/523952/
IEEE Industrial Applications Magazine, Vol. 3, No. 2, March/April 1997. 1077-2618/97 IEEE.
http://ieeexplore.ieee.org/document/579139/
Power Quality and Harmonic Distortion on Distribution Systems
Abstract:
With the increase of non-linear loads on utility distribution systems, the voltage and current waveforms are becoming more distorted and the power quality is deteriorating. Since this is becoming a wide spread problem today, and new, more strict, distortion guidelines are under development, utility engineers are having to deal with analyzing and planning for the control of the distortion. This paper introduces some common harmonic analysis techniques and applies them to voltage wave-forms recorded on a typical REA transmission and distribution system.
Co-authors:
J.K. Phipps, J.P. Nelson, P.K. Sen
Publications:
IEEE Transactions on Industry Applications, VOL. 30, NO. 2, MARCH/APRIL, 1994. IEEE Log Number 9216400.
http://ieeexplore.ieee.org/document/287506/
A Harmonic Distortion Control Technique Applied to Six-Pulse Bridge Converters
Abstract:
This paper presents a practical design aspect for controlling power system harmonics through the use of transformer connections applied to a distributed set of six-pulse converter type loads in industrial power distribution systems. Since several papers have already been written on nonlinear converter loads, power system harmonics, harmonic modeling and analysis, and capacitor bank filter design, this paper does not attempt to reinvent the "wheel!" Rather, the intent is to define some common system problems associated with harmonic distortion from six-pulse type converters and present a method for reducing harmonic distortion through the use of transformer bank connections to allow for harmonic cancellation.
Co-authors:
J.K. Phipps, J.P. Nelson
Publications:
IEEE Transactions on Industry Applications, VOL. 29 NO. 3, MAY/JUNE 1993. IEEE Log Number 9208804.
http://ieeexplore.ieee.org/document/222434/
Residential Harmonic Current Injection in Distribution Feeders: An IEEE-519 Evaluation
Abstract:
This paper summarizes harmonic distortion test results for typical home load mixes which use various combinations of common linear loads, voltage controlled loads, and nonlinear rectifier/converter loads. The harmonic distortion produced by these load mixes are compared to IEEE-519 limits for both voltage and current distortion at the primary and secondary points of common coupling with a 10 kVA, 7,200-120/240 V, single phase, pole mount distribution transformer. The results are expressed using a per unit system based on a 10 kVA per home 12 month average maximum 15 minute demand. Typical current time domain waveforms of common nonlinear loads which are associated with residential use are also documented for comparison. In an effort to aid utility distribution power quality planning, the harmonic current produced by typical nonlinear loads is summarized on a per-device and a per-home basis.
Co-authors:
J.K. Phipps, C.A. Riggio, D.J. Pileggi, R.J. Schneider
Publications:
https://www.academia.edu/34490201
Phase Shifting Transformers and Passive Harmonic Filters: Interfacing for Power Electronic Motor Drive Converters
Abstract:
This thesis details the analysis and design of electric power systems with power electronic industrial converter loads for the reduction and control of harmonic distortion produced by their non-linear characteristics. A technique for harmonic component cancellation resulting from transformer phase shifting is discussed in theory and measurements are shown to support the theory. Four different types of phase shifting transformer winding connections based on three and four winding transformer core arrangements are presented. A general mathematical approach for describing unbalanced harmonic conditions is devised based on symmetrical component theory and the result is used to predict symmetrical component phase shifts through transformers of arbitrary winding displacement. Four passive filter configurations are introduced and the associated design equations are derived using a transfer function approach. A filter design procedure is outlined based on the applicable harmonic limits established by ANSI/IEEE Std 519-1993 and an application of the design procedure is presented. An example is presented where a phase shifting transformer is used in conjunction with passive harmonic filters to reduce voltage and current distortion from two independent ski lift motor drives.
Author:
J.K. Phipps
Publications:
University of Colorado at Denver, MSEE Thesis, April 1993.
Auraria Library
http://digital.auraria.edu