Condition monitoring of disconnectors in the electric power transmission grid with temperature sensors

Abstract

This paper presents a method that can be used to rank disconnectors in the electric power system, according to the condition of one of the most critical parts, the contacts. The temperature of the contacts can be continuously measured by a new type of infrared sensor. For the case study, 54 sensors were placed on six disconnectors together with reference sensors measuring the ambient temperature. The measured temperature at each contact is then regressed against the ambient temperature and the current through the disconnector. Both a linear and a quadratic dependency of the current are tested and the quadratic one explains the data best. The coefficient of the current serves as a measure of the condition of the contact. Then, it becomes possible to identify in which contacts the resistance has increased the most. As a consequence, it is possible to make better maintenance decisions for the disconnectors.

Towards Health Assessment: Failure Analysis and Recommendation Of Condition Monitoring Techniques for Large Disconnector Populations

“…However, to measure the resistance of the contacts, the disconnector needs to be out of operation. Hence, an alternative is the measurement of the temperature of the contacts with a new type of infrared sensor [9]. The authors in [9] showed that with additional ambient temperature and current measurement, the coefficient of the current can serve as a measure of the condition of the contacts.…”

“…Hence, an alternative is the measurement of the temperature of the contacts with a new type of infrared sensor [9]. The authors in [9] showed that with additional ambient temperature and current measurement, the coefficient of the current can serve as a measure of the condition of the contacts. This method becomes cost intensive in large disconnector populations due to the installation of nine temperature sensors, three on each phase of the disconnector and the connection to a wireless communication with is mostly only available in substations.…”

A review of methods for condition monitoring, surveys and statistical analyses of disconnectors and circuit breakers

“…Then they follow the ratio between the temperature rise of two contacts. Westerlund et al have used IR sensors to follow the condition of disconnector contacts with a model to explain the temperature rise as a function of the current [57].…”