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Transformer Fluid Monitoring Device

IP.com Disclosure Number: IPCOM000201549D
Publication Date: 2010-Nov-15
Document File: 3 page(s) / 30K

Publishing Venue

The IP.com Prior Art Database

Abstract

Traditionally the health condition of a transformer is monitored in periodic intervals of six months to two years by extracting manually samples of insulation fluid for laboratory analysis of dissolved gases. The consequences of faults, however, can occur very quickly and might not be detected in time by periodic regular analysis. Due to cost constraints continuous monitoring is limited to high-value or to critical transformers and therefore most transformers are not continuously monitored. The benefits of continuous monitoring are a faster detection of transformer misoperation, thus avoiding the consequences of transformer breakdown (loss in produced energy, process down-time) and the ability to better manage just-in-time fluid laboratory analysis. Online monitoring of hydrogen and moisture in transformer fluid allows to detect and solve in time transformer malfunctions such as partial discharging, arcing, and paper degradation Recent advances in palladium, palladium-nickel and other palladium alloy devices for hydrogen monitoring have led to an improved selectivity to the measurement of hydrogen. While the technology was largely developed for hydrogen based transportation systems, it can be modified to be operated in transformer fluids. Combining a selective palladium-alloy hydrogen sensor with a commercial capacitive moisture sensor allows developing a low-cost device for online monitoring of failures in transformers.

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Idea: Barbara Panella, Hubert Braendle, Julio Danin Lobo Neto

Background of the invention

Traditionally the health condition of a transformer is monitored in periodic intervals of six months to two years by extracting manually samples of insulation fluid for laboratory analysis of dissolved gases. The consequences of faults, however, can occur very quickly and might not be detected in time by periodic regular analysis.

Due to cost constraints continuous monitoring is limited to high-value or to critical transformers and therefore most transformers are not continuously monitored. The benefits of continuous monitoring are a faster detection of transformer misoperation, thus avoiding the consequences of transformer breakdown (loss in produced energy, process down-time) and the ability to better manage just-in-time fluid laboratory analysis.[1], [2] Online monitoring of hydrogen and moisture in transformer fluid allows to detect and solve in time transformer malfunctions such as partial discharging, arcing, and paper degradation
Recent advances in palladium, palladium-nickel and other palladium alloy devices for hydrogen monitoring have led to an improved selectivity to the measurement of hydrogen [3], [4]. While the technology was largely developed for hydrogen based transportation systems, it can be modified to be operated in transformer fluids. Combining a selective palladium-alloy hydrogen sensor with a commercial capacitive moisture sensor allows developing a low-cost device for online monitoring of failures in transformers.

State-of-the-art solutions

Typically for critical transformers multi-component devices with a combined gas extraction and detection system are employed for online monitoring (i.e. gas chromatography, infrared, or photoacustic spectroscopy). Low-cost solutions use fuel cell sensors for the detection of reducing gases [5] or hydrogen detection systems which measure changes in thermal conductivity of the gas. In both cases the sensing device is not directly immersed in fluid, but detects the gases after separation through a semipermeable membrane [5], [6]. Fuel cell sensors additionally require oxygen to burn the reducing gases to be detected and is non-selective. Devices which measure thermal conductivity to detect hydrogen suffer strong cross sensitivity. Recently a hydrogen sensor based on palladium and palladium-alloy nanobreakjunctions which swell during exposure to hydrogen, was described for hydrogen detection in transformer fluid [7]. The resistance of the sensor decreases when exposed to hydrogen. This kind of sensor is sensitive to the changes in size and shape of the palladium nanoparticles, which could occur during repeated hydrogen absorption or at high temperatures. Therefore a sensor based on a palladium or palladium-alloy thin film is more reliable than one based on nanobreakjuncti...