Breakdown Voltage Estimation in Transformer Oils with Low-Cost Humidity Sensor

Year 2024, Volume: 7 Issue: 1, 9 - 19, 31.05.2024

Doruk Güneş , Hüsnügül Tekin , Bora Alboyacı , Özgür Yılmaz

https://doi.org/10.34088/kojose.1115308

Abstract

The relative humidity and temperature of the oil used for insulation purposes in transformers directly affect the breakdown voltage of the oil and accordingly the life of the transformer. Continuous monitoring of the moisture content and breakdown voltage of the transformer oil provides the basis for predictive maintenance practices. This study aims to develop a sensor to continuously monitor the moisture content of the insulating oil and to calculate the breakdown voltage approximately. In this context, firstly, measurements were taken with an industrial oil monitoring sensor which calculates the breakdown voltage in transformer oils with high accuracy and was verified with laboratory measurements. At the same time, EE364 by E+E™ and SHT10 by Sensirion™ also used for temperature and humidity measurements. By comparing the measured data with each other, a relationship was formulated between the humidity and temperature values and the breakdown voltage. As a result, an approximate breakdown voltage calculation method that can be used considering the characteristic parameters of transformer oil has been introduced. Thus, a cost-effective function has been developed that can be widely used for transformer monitoring systems.

Keywords

Breakdown Voltage, Humidity Sensor, Moisture in Oil, Relative Saturation, Water activity, Water Content

References

• [1] Dupont C., Beauchemin C., Buckley G., Bukvic M., 2015. Cigré Brochure 630 A2.44 -Guide On Transformer Intelligent Condition Monitoring (TICM) Systems. CIGRE Tech Broch.
• [2] Tenbohlen S., Jagers J., Bastos G., Desai B., Diggin B., 2015. Cigré Brochure 642 A2.37 -Transformer Reliability Survey. CIGRE Tech Broch.
• [3] Atanasova I., Agren P., Cucek B., Davidov V., 2018., Cigré Brochure 741 D1.52 -Moisture Measurement and Assessment in Transformer Insulation – Evaluation of Chemical Methods And Moisture Capacitive Sensors. CIGRE Tech Broch.
• [4] Pahlavanpour B., Pablo A., Tumiatti W., Martins M., 2010. Cigré Brochure 413 D1.01 -Insulating Oil Regeneration and Dehalogenation. CIGRE Tech Broch.
• [5] Solokov V., Aubin J., Davydov V., Gasser H., Griffin P., 2008. Cigré Brochure 349 A2.30 - Moisture Equilibrium and Moisture Migration Within Transformer Insulation Systems. CIGRE Tech Broch.
• [6] Du Y., 1999. Moisture equilibrium in transformer paper-oil systems. IEEE Electrical Insulation Magazine, 15, pp.11–20.
• [7] Julliard Y., Badent R., Schwab AJ., 2001. Influence of water content on breakdown behavior of transformer oil. Paper presented at Annual Report Conference on Electrical Insulation and Dielectric Phenomena, Kitchener, Canada, 14-17 October, pp. 544–547.
• [8] Lewand L., 2002. Understanding Water in Transformer Systems. Neta World, pp. 1–4.
• [9] Roizman O., 2019. Moisture equilibrium in transformer insulation systems: Mirage or reality? Part 1. Transformers Magazine, 6, pp. 44–51.
• [10] Gradnik T., Končan-Gradnik M., Petric N., Muc N., 2011. Experimental evaluation of water content determination in transformer oil by moisture sensor. Paper presented at IEEE International Conference on Dielectric Liquids, Trondheim, Norway, 26-30 June, pp. 1–4.
• [11] Wrobel M., 2017. Acoustic hybrid sensor for BDV monitoring in insulating oil. Paper presented at IEEE International Ultrasonics Symposium, Washington, DC, USA, 6-9 September, pp. 1–5.
• [12] Martin D., Saha T., Perkasa C., Lelekakis N., Gradnik T., 2016. Fundamental concepts of using water activity probes to assess transformer insulation water content IEEE Electrical Insulation Magazine, 32, pp. 9–16.
• [13] Pagger E., Muhr M., Pattanadech N., Kongdang P., Tieber M., Rapp K., Maneerot S., 2020. How Water Affects the Properties of Insulating Liquids. Paper presented at 8th International Conference on Condition Monitoring and Diagnosis, Phuket, Thailan, 25-28 October, pp. 322–325.
• [14] Gradnik T., Čuček B., Končan-Gradnik M., 2014. Temperature and chemical impact on determination of water content in dielectric liquids by capacitive moisture sensors. Paper presented at 2014 IEEE 18th International Conference on Dielectric Liquids, Bled, Slovenia, 29 June-3 July, pp. 1–5.
• [15] Du Y., Mamishev A V., Lesieutre BC., Zahn M., Kang SH., 2001. Moisture Solubility for Differently Conditioned Transformer Oils. IEEE Transactions on Dielectrics and Electrical Insulation, 8, pp. 805–811.
• [16] Villarroel R., García de Burgos B., García DF., 2021. Moisture dynamics in natural-ester filled transformers. International Journal of Electrical Power & Energy Systems, 124, pp. 1–11.
• [17] Hasheminezhad M., Ildstada Nysveen E., 2008. Electrical breakdown strength of interfaces between solid insulation and transformer oil with variable water content. Paper presented at Conference on Electrical Insulation and Dielectric Phenomena, Quebec, QC, Canada, 26-29 October, pp. 575–578.
• [18] Cybulski M., Przybylek P., 2021. Application of molecular sieves for drying transformers insulated with mineral oil, natural ester, or synthetic ester. Energies, 14, pp. 1–13.
• [19] Nurcahyanto H,, Nainggolan JM,, Ardita IM,, Hudaya C,, 2019. Analysis of Power Transformer’s Lifetime Using Health Index Transformer Method Based on Artificial Neural Network Modeling. Paper presented at International Conference on Electrical Engineering and Informatics, Bandung, Indonesia, 9-10 July, pp. 574–579.
• [20] Azmi A., Jasni J., Azis N., Kadir MZAA., 2017. Evolution of transformer health index in the form of mathematical equation. Renew Sustain Energy Rev, 76, pp. 687–700.
• [21] Trafostick™ website, https://en.passerro.eu/Trafostick™.
• [22] E+E364 website, https://www.epluse.com/products/moisture-in-oil-instrumentation/oil-measurement-transmitter/ee364/.
• [23] Sensirion website, https://www.sensirion.com/en/environmental-sensors/humidity-sensors/.
• [24] Solokov V., Alcantara G., Astrom B., Aubin J., 2003. Cigré Brochure 227 A2.18 -Life Management Techniques for Power Transformers. CIGRE Tech Broch.
• [25] IEC International Standart-TC 10. IEC 60156: Insulating liquids — Determination of the breakdown voltage at power frequency — Test method, 1996.
• [26] IEC International Standart-TC 10. IEC 60422: Mineral insulating oils in electrical equipment — Supervision and maintenance guidance, 2013.
• [27] IEEE Guide for the Evaluation and Reconditioning of Liquid Immersed Power Transformers. IEEE Std C57140-2006.