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Using IEEE Flash to Estimate Transmission and Distribution Line Lightning Performance T. E. McDermott, Senior Member, IEEE 3. Abstract—For many years, an IEEE program called Flash was maintained to estimate flashover rates on transmission lines. With recent consolidation of two Working Groups, a new version of Flash has been developed to consistently treat both transmission and distribution lines. The new software includes line arresters, shield wires, tower and pole grounding, and insulation added by wood or fiberglass. The program also incorporates electromagnetic transient simulation. Examples from transmission and distribution lines are presented. Index Terms — Arresters, Power distribution protection, Power system lightning effects, Power transmission protection, Surge protection.
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I. INTRODUCTION
EEE and PES have developed several standards and application guides to help engineers design overhead lines for good lightning performance [1-6]. Previous versions of IEEE Std. 1243 have included a software tool for estimating lightning trip-out rates and required shielding angles for transmission lines. That software has been useful to many transmission engineers, even with simplified underlying models, because it provides the distilled experience and guidance of the working group members in a convenient form. This paper summarizes an update to the software tool, now called IEEE Flash [7]. The software has also been extended to cover distribution lines and line arresters for lightning protection.
Shielding analysis using an electrogeometric model (EGM), or alternative module. 4. Impact of tower surge impedance, span length, corona, and conductor characteristics. 5. Estimates of backflash rates and the performance of tower or pole grounding methods. 6. Estimates of induced voltages and flashovers from nearby strokes, using a modified Rusck formula. 7. Estimates of line arrester impact on flashover rates. 8. Estimates of line arrester failure rates. 9. Waveform plotting from electromagnetic transient (EMT) simulation. 10. Graphical display of shielding estimates for a specified lighting stroke. 11. Estimate of critical current magnitude to cause flashover for a specified lightning stroke. 12. Implementation in Microsoft Excel using Visual Basic for Applications (VBA). Items 10 and 11 support the investigation of lightning tripouts using data from lightning detection networks. Alternative calculation methods may be substituted by other researchers for any of these items. IEEE Flash provides an overall framework and a default implementation of each required function.
II. NEW VERSION OF IEEE FLASH It is a design goal of Flash 2.0 to provide quick estimates of line and arrester performance, commensurate with uncertainties in the data and models, and suitable for use by utility engineers. With implementation in Microsoft Excel, shown in Fig. 1, it is expected that a newer generation of students and researchers can readily extend the program. A summary feature list of IEEE Flash follows: 1. 2.
Consolidated treatment of transmission and distribution lines. Insulation strength described by a volt-time curve, or alternative module, with critical flashover voltage (CFO) added by wood, fiberglass, and similar secondary or tertiary insulating materials.
T. E. McDermott is with MelTran, Inc., Pittsburgh, PA 15236 (email:
[email protected]).
978-1-4673-1935-5/12/$31.00 ©2012 IEEE
Fig. 1. IEEE Flash 2.0 user interface.
III. ELECTROMAGNETIC TRANSIENT SIMULATION During the period from 1990 through 2002, EPRI funded the development of a Lightning Protection Design Workstation (LPDW) [8]. Many utilities used LPDW to assess the lightning performance of distribution lines. Since about
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2002, this program has not been available. EPRI decided to release the simulation kernel of LPDW under the name OpenETran, with an open-source license (GPL v3), so it may be incorporated into IEEE Flash and other projects [9]. EPRI originally had permission to use code from the Numerical Recipes book in LPDW [10]. Due to licensing restrictions, these routines have been removed in favor of the GNU Scientific Library (GSL), which also uses the GPL v3 license. OpenETran can presently simulate multi-conductor power lines, insulators, surge arresters, non-linear grounds, and lightning strokes. It efficiently calculates energy and charge duty on surge arresters, and iterates to find the critical lightning current causing flashover on one or more phases. It is also suitable for use in substation insulation coordination. IV. CONCLUSION The new version of IEEE Flash provides a convenient open-source tool to design the lightning protection of overhead lines, and to investigate lightning trip-outs. Interested researchers may also help with software enhancements by contacting the project administrators at [3] or [7]. At present, the most pressing needs are for better models of shielding (EGM or alternatives), tower grounding and surge impedance, and voltages induced from nearby strokes. V. REFERENCES [1]
IEEE Design Guide for Improving the Lightning Performance of Transmission Lines, IEEE Std. 1243-1997 (reaffirmed 2008). [2] IEEE Guide for Improving the Lightning Performance of Electric Power Overhead Distribution Lines, IEEE Std. 1410-2010. [3] IEEE PES Lightning Performance of Overhead Lines Working Group 15.09.08, [Online]. Available: ewh.ieee.org/soc/pes/lpdl/ [4] IEEE Working Group on Estimating the Lightning Performance of Transmission Lines, “A Simplified Method for Estimating Lightning Performance of Transmission Lines,” IEEE Transactions on Power Apparatus and Systems, vol. PAS-104, pp 919–932, 1985. [5] IEEE Working Group on Estimating the Lightning Performance of Transmission Lines, “IEEE Working Group Report—Estimating Lightning Performance of Transmission Lines II—Updates to Analytical Models,” IEEE Transactions on Power Delivery, vol. PWRD-8, no. 3, pp. 1254–1267, 1993. [6] IEEE Guide for the Application of Metal-Oxide Surge Arresters for Alternating-Current Systems, IEEE Std. C62.22-2009. [7] IEEE Flash [Online]. Available: sourceforge.net/projects/ieeeflash/ [8] T. E. McDermott and V. J. Longo, "Advanced Computational Methods in Lightning Performance - the EPRI Lightning Protection Design Workstation", Proc. IEEE/PES Winter Power Meeting, Singapore, January 2000. [9] OpenEtran [Online]. Available: sourceforge.net/projects/openetran/ [10] W. H. Press, B. P. Flannery, S. A. Teukolsky, W. T. Vetterling, Numerical Recipes in C: The Art of Scientific Computing, 2nd ed., Cambridge University Press, 1992.
VI. BIOGRAPHY Thomas E. McDermott (SM 1990) is President of MelTran, a power system consulting company based in Pittsburgh. The company specializes in applied R&D for distribution systems and smart grid applications, distributed resource interconnection, custom software development, and electromagnetic transient studies. He is currently Chairman of the Working Group on System Impacts and Interconnection Requirements of Wind and Solar Power Plants, a U.S. delegate to IEC TC 57 Working Group 14, and a task force leader in Cigre WG C4.502 for system performance of long AC cables. He has previously chaired the Pittsburgh Section IEEE and the Working Group on Estimating
Lightning Performance of Transmission Lines. Tom is a registered professional engineer in Pennsylvania. He has a B. S. and M. Eng. in Electric Power from Rensselaer, and a Ph.D. in Electrical Engineering from Virginia Tech.
