Measuring cell for studying the characteristics of partial discharges in gas defects of insulation

The actuality of the study is to calculate the design of a cell to measure the characteristics of partial discharges (PD) occurring in gas defects within solid insulation. The size and volume of gas inclusions in the insulation are related to the PD characteristics that occur in these defects. Knowledge of the details of this relationship for defects of various sizes and shapes is necessary for proper diagnosis of the insulation condition of high voltage apparatuses and determination of their residual life. This connection is currently studied to an insufficient extent. The task of studying PDs is complicated by their small magnitude and the difficulty of separating PDs in gas defects from surface, corona PDs and extraneous random noises having a similar spectrum.

Objective of the work is to create an experimental setup with a measuring cell in which there are no corona and surface PDs, which complicate obtaining reliable results when measuring PDs in gas pores of a dielectric.

Methods. The calculation of the electric field strength in various cell designs by the finite element method in the ComSol-Multiphysice 6.0 program was used to solve the problem.

Results. The paper describes the relevance of the topic, presents the results of calculation of electric field distribution at different configurations of highvoltage electrodes, the results of PD measurements in control (defect-free) samples and samples with defects. It is proved that in the proposed design of the cell there are no surface and corona PDs on the electrodes, which allows us to study the characteristics of PDs in gas defects of insulation. It is established that PDs in a gas defect occur in the first and third parts of each period of a sinusoid of industrial frequency at the same potential difference between the electrodes. No shift of the PD occurrence voltage, which was predicted due to the assumed residual charge on the cavern walls, was found.

1. Vdoviko, V.P. Partial discharges in diagnostics of the high-voltage equipment (in Russian) // Novosibirsk: Nauka. - 2007. - 155c.

2. Rusov, V.A. Measurement of the partial discharges in the insulation of the high-voltage equipment. // Yekaterinburg: UrGUPS, 2011. - 370 с. - ISBN: 978-5-94614-177-2.

3. Taylor N. A literature review: The nature of partial discharges in stator insulation. // ETK, KTH. 2008. P.34.

4. Kaziz S., Said M.H., Imburgia A., Maamer M, Flandre D., Romano P., Tounsi F. Radiometric Partial Discharge Detection: A Review. // Energies 2023, 16, 1978.

5. Zhang X., Pang B., Liu Y., Liu S., Xu P., Li Y., Liu Y., Qi L., Hie Q. Review on detection and analysis of partial discharge along power cables. // Energies, 2021, 14 (22), 7692,

6. Raziq H., Batoola M., Nawaz F., Akgul A., Afzal F., Hassani M.K.. A review on analysis and modeling of electrical machine insulation system. // Electrical & Electronic Engineering, 2024, V.11, 2400614.

7. Ba Boraik A.M., Usachev A.E., Kubarev A.Yu., Ildarkhanov R.G. New methodology for determination of the sizes and positions of the defects in the insulation of the stator windings of the turbogenerators at the measurements of the partial discharges in them. // Izvestiya Vuzov. Problems of power engineering. 2018. Т.20. № 1-2. С. 41-53.

8. Baboraik A.M., Usachev A.E.. New model of explanation for phase angle pattern of online partial discharge measurement in winding insulation of turbine generator. // Journal of ELECTRICAL ENGINEERING, V.72 (2021), pp.66-77.

9. Kubarev A.Yu., Usachev A.E., Mikhailova E.V. Modeling of partial discharge waveforms in a generalized model of power transformer insulation // 2021 International Conference on Industrial Engineering, Applications and Manufacturing (ICIEAM). DOI: 10.1109/ICIEAM51226.2021.9446437; ISBN Information: Electronic ISBN:978-1-7281-4587-7; USB ISBN:978-1-5386-1797-7; Print on Demand (PoD) ISBN:978-1-7281-4588-4

10. Kubarev A.Yu., Usachev A.E., Paramonov M.A. Analysis of power transformer monitoring systems // 2024 International Conference on Industrial Engineering, Applications and Manufacturing (ICIEAM). DOI: 10.1109/ICIEAM60818.2024.10553850 Electronic ISBN:979-8- 3503-9501-3 USB ISBN:979-8-3503-9500-6 Print on Demand (PoD) ISBN:979-8-3503-9502-0

11. Illias H. A., Chen G., Lewin P. L. Modeling of partial discharges from a spherical cavity inside a dielectric material in electric fields of variable frequency // Electrical Insulation and Dielectric Phenomena, 2008. CEIDP 2008. Annual reporting conference. - IEEE, 2008. - С. 447- 450.

12. Illias H. A., Chen G., Lewin P. L. Effect of surface charge distribution on the electric field in a void due to partial discharges // Electrical Insulating Materials (ISEIM), Proceedings of the 2011 International Conference on. - IEEE, 2011. - С. 245-248.

13. Alexandrov A.F., Bychkov V.L., Grachev L.P., Esakov I.I., Lomteva A.Yu. Ionization of air in near-critical electric field. // ZhTF, 2006, vol. 76, v.3, p.38-43.

14. Mesyats G. A. Similarity laws in pulsed gas discharges. // UVN. Reviews of Actual Problems 2006. Vol.176, No.10, pp.1069-1091.

15. Luo B., Wang J., Dai D., Jia L., Li., Wang T. Partial Discharge Simulation of Air Gap Defects in Oil-Paper Insulation Paperboard of Converter Transformer under Different Ratios of AC-DC Combined Voltage // Energies, 2021, 14, 6995.

16. Kincht, N.V.; Borisov, B.D.; Petrunko, N.N. Assessment questions of the multiple partial discharges in the high-voltage equipment. // Electricity. Transmission and Distribution, 2019 № 2(53).