“Capacitive Sensor” to Measure Flow Electrification and Prevent Electrostatic Hazards

Abstract

At a solid/liquid interface, physico-chemical phenomena occur that lead to the separation of electrical charges, establishing a zone called electrical double layer. The convection of one part of these charges by the liquid flow is the cause of the flow electrification phenomenon which is suspected of being responsible of incidents in the industry. The P' Institute of Poitiers University and CNRS has developed an original sensor called “capacitive sensor” that allows the characterization of the mechanisms involved in the generation, accumulation and transfer of charges. As an example, this sensor included in the design of high power transformers, could easily show the evolution of electrostatic charge generation developed during the operating time of the transformer and, therefore, point out the operations leading to electrostatic hazards and, then, monitor the transformer to prevent such risks.

Electrical-Based Diagnostic Techniques for Assessing Insulation Condition in Aged Transformers

“…Since ECT affects volume resistivities, partial discharges (PDs) and dielectric losses, a capacitive sensor was recently proposed to assess power transformer behaviour towards flow electrification and electrostatic hazard. This capacitive sensor is intended for online monitoring of the flow electrification hazards in transformers [39].…”

Direct observation of electric charges at solid/liquid interfaces with the pressure-wave-propagation method

“…The main measurement methods to study electric phenomena arising at solid/liquid interfaces rely on electrostatics. Charges in the diffuse layer are dragged by the liquid flow and are measured in turn by charge counting, current measurement in the fluid flow, potential variation, or generated current measurement [39,40,41,42]. These measurement methods are very sensitive but work only in dynamic equilibrium, so they do not give access to the complete image of the interface phenomena.…”

Adoption of response surface methodology for optimization of benzotriazole additive in ester fluids as transformer insulant

“…Since then, numerous researchers worldwide have been conducting experiments on the streaming electrification phenomenon with different laboratory models [2,3]. Initially, the pilot scale model simulating the actual power transformer was investigated [4] which then advanced towards cylindrical system [5] due to the process involved in the pre-conditioning and lower cost involved in the technique. The mineral oil which is widely used in power transformers for the last 50 years have been tested by different models towards streaming phenomenon with pressboard material as its interface [2].…”