The rise of Distributed Energy Resources (DERs) has transformed the power industry, posing challenges for system operation and grid planning. Low Power Instrument Transformer (LPIT) technology enables utilities to obtain reliable data, improving predictive insights and decisionmaking. However, capacitive voltage-based LPITs face technical challenges, particularly in maintaining long-term accuracy. Electro-thermal aging can cause irreversible degradation of dielectric materials, with hygrothermal aging (humidity and thermal stress) being the primary factor. This aging leads to “voltage drift,” where sensor accuracy declines due to changes in the dielectric material’s permittivity within the primary capacitance of the voltage dividers.

This paper aims to investigate the impact of combined temperature and humidity on epoxy durability using weight measurement, dynamic scanning calorimetry and dielectric spectroscopy. Tests have been conducted on different epoxies, incorporating different kinds of fillers. The primary objective is to investigate the impact of water absorption on the material properties, develop an approximate water diffusion model for the tested epoxies, and quantify the extent of water sorption within the material.

Marine MOYROUD, Sophie Iglesias, Anatole Collet, Marie-Hélène Luton, Mattewos Tefferi (G&W USA)

Presented at CEIDP 2025

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