A Simplified Method of Flexible Conductors Mechanic Calculation in Switchgears without Restrictions on the Number of Taps

The purpose of the mechanical calculation of flexible conductors of switchgears and power lines is to determine the sag, tensions, and loads on support structures, minimum distances to adjacent live parts and some other parameters. Calculations should be made taking into account distributed and concentrated loads. Distributed loads directed vertically are determined by the weight of the wire, insulator strings, and possible ice deposits on them. Distributed loads in the horizontal plane should be calculated in climatic conditions with lateral wind pressure. Concentrated loads are created by such elements as taps to electrical devices, phase-to-phase insulating spacers, barrier balls, loops, etc. Concentrated loads mainly act in the vertical plane, and in the case of taps, they can have an almost arbitrary spatial direction. The most accurate methods of mechanical calculation of flexible conductors include methods based on the numerical solution of the equation of wires in the form of a flexible elastic thread. Such an algorithm is implemented in the author's computer program MR21. However, in many cases, simplified methods of mechanical calculation are preferable, as they are available to a wider range of users. The simplified method of mechanical calculation of flexible conductors proposed in the article is based on the equation of state of the wire and allows taking into account concentrated and distributed loads. Various climatic regimes and loads are taken into account using the horizontal and vertical load factors in the calculated and initial modes. Expressions are proposed for calculating the above coefficients for any number of taps in a span and with an accurate approach to taking into account their spatial arrangement. Formulas for calculating sag and horizontal deflections of conductors are given, too. The MR21 computer program, tested earlier, has been used in this work as a tool for checking the calculation results using the proposed simplified method.

1. Bladyko Y. V. (2018) Mechanical Calculation of Flexible Wires when the Concentrated Forces are Replaced by a Distributed Load. Energetika. Izvestiya Vysshikh Uchebnykh Zavedenii i Energeticheskikh Ob’edenenii SNG = Energetika. Proceedings of the CIS Higher Educational Institutions and Power Engineering Associations, 61 (2), 97–107 (in Russian). https://doi.org/10.21122/1029-7448-2018-61-2-97-107

2. Sergey I. I., Bladyko Y. V. (2018) Mechanical Calculation of Flexible Wires of Overhead Lines with Barrage Balls. Energetika. Izvestiya Vysshikh Uchebnykh Zavedenii i Energeticheskikh Ob’edenenii SNG = Energetika. Proceedings of the CIS Higher Educational Institutions and Power Engineering Associations, 61 (4), 299–309 (in Russian). https://doi.org/10.21122/1029-7448-2018-61-4-299-309

3. Bladyko Y. V. (2019) Mechanical Calculation of Flexible Wires of Overhead Lines with Aerial Barrage Balls in Different Climatic Regimes. Energetika. Izvestiya Vysshikh Uchebnykh Zavedenii i Energeticheskikh Ob’edenenii SNG = Energetika. Proceedings of the CIS Higher Educational Institutions and Power Engineering Associations, 62 (1), 24–36 (in Russian). https://doi.org/10.21122/1029-7448-2019-62-1-24-36

4. Bladyko Y. V. (2019) Accounting for Spacers in the Mechanical Calculation of Flexible Wires for Overhead Lines and Switchgears. Energetika. Izvestiya Vysshikh Uchebnykh Zavedenii i Energeticheskikh Ob’edenenii SNG = Energetika. Proceedings of the CIS Higher Educational Institutions and Power Engineering Associations, 62 (3), 219–231 (in Russian). https://doi.org/10.21122/1029-7448-2019-62-3-219-231

5. Bladyko Y. V. (2020) Mechanical Calculation of Flexible Wires of Spans with Different Tensioning Insulator Strings. Energetika. Izvestiya Vysshikh Uchebnykh Zavedenii i Energeticheskikh Ob’edenenii SNG = Energetika. Proceedings of the CIS Higher Educational Institutions and Power Engineering Associations, 63 (1), 55–65 (in Russian). https://doi.org/10.21122/1029-7448-2020-63-1-55-65

6. Bladyko Y. V. (2020) Mechanical Calculation of Flexible Wires Loaded with Concentrated Loads. Energetika. Izvestiya Vysshikh Uchebnykh Zavedenii i Energeticheskikh Ob’edenenii SNG = Energetika. Proceedings of the CIS Higher Educational Institutions and Power Engineering Associations, 63 (2), 103–115 (in Russian). https://doi.org/10.21122/1029-7448-2020-63-2-103-115

7. Bladyko Yu.V. (2020) Mechanical Calculation of Flexible Wires in the Presence of Horizontal Concentrated Loads. Energetika. Izvestiya Vysshikh Uchebnykh Zavedenii i Energeticheskikh Ob’edenenii SNG = Energetika. Proceedings of the CIS Higher Educational Institutions and Power Engineering Associations, 63 (6), 500-514 (in Russian). https://doi.org/10.21122/1029-7448-2020-63-6-500-514

8. Strelyuk M. I., Sergey I. I., Bladyko Y. V. (1983) Numerical Method for Calculating the Statics of a Flexible Busbars of Open Distribution Devices in Various Modes of Climatic Influences. Izvestiya vysshikh uchebnykh zavedenii Ministerstva vysshego i srednego spetsial'nogo obrazovaniya SSSR. Energetika [Proceedings of Higher Educational Institutions of the USSR Ministry of Higher and Secondary Special Education. Power Engineering], (8), 8–14 (in Russian).

9. Strelyuk M. I., Sergey I. I., Bladyko Y. V. (1988) Vector-Parametric Method of Mechanical Calculation of Flexible Current Wires of Electrical Installations of Power Systems. Matematicheskie Metody v Elektroenergetike: Materialy II Mezhdunar. Simpoz. Zakopane, 10–12 Noyab. 1988 [Mathematical Methods in the Electric Power Industry: Materials of the II International Simposium. Zakopane, 10–12 Nov. 1988]. Zakopane, 173–181 (in Russian).

10. Streliuk M. I., Sergey I. I., Bladyko Y. V. (1995) Computer Aided Program of Mechanical Calculation of Flexible Conductors for Substations and Overhead Lines Design. New Electrical and Electronic Technologies and their Industrial Implementation: Proc. Int. Conf. Lublin (Poland), 7–8 Sept. Lublin, Lublin Technical University, 15–19.

11. Strelyuk M. I., Sergei I. I., Bladyko Y. V. (1995) Numerical Method of Mechanical Calculation of Flexible Current Conductors of Power Units of Power Systems. Energetika. Izvestiya Vysshikh Uchebnykh Zavedenii i Energeticheskikh Ob’edenenii SNG = Energetika. Proceedings of the CIS Higher Educational Institutions and Power Engineering Associations, (3–4), 21–29 (in Russian).

12. Sergey I. I., Bladyko Y. V., Ponomarenko E. G., Klimkovich P. I. (2015) Software Package for Mechanical and Electrodynamic Calculation of Flexible Current-Carrying Structures. Metodicheskie voprosy issledovaniya nadezhnosti bol'shikh sistem energetiki. Materialy Mezhdunarodnogo seminara imeni Yu. N. Rudenko [Methodological issues of reliability research for large energy systems. Materials of the International Seminar named after Yu. N. Rudenko]. Minsk, BNTU, 308–310 (in Russian).

13. Bladyko Y. V., Ponomarenko E. G. (2021) Mechanical Calculation of Flexible Wires Taking into Account Taps to Electrical Apparatuses. Energetika. Izvestiya Vysshikh Uchebnykh Zavedenii i Energeticheskikh Ob’edenenii SNG = Energetika. Proceedings of the CIS Higher Educational Institutions and Power Engineering Associations, 64 (2), 109–120 (in Russian). https://doi.org/10.21122/1029-7448-2021-64-2-109-120