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Wir demonstrieren die Machbarkeit rückwirkungsfrei integrierter optischer Teilentladungssensorik für Aufschiebeelemente aus Silikonelastomer zur Verwendung in Kabelgarnituren. Zu diesem Zweck wurden sowohl ein Funktionsmodell eines optisch transparenten Silikon-Kabelendverschlusses mit integriertem Silikon-Lichtwellenleitersensor als auch ein rein optisches TE-Messsystem auf Basis von zwei Einzelphotonendetektoren und einer Koinzidenzschaltung (PD-COP) entwickelt, die hier vorgestellt werden. Die Leistungsfähigkeit und Stärken der optischen TE-Messtechnik zeigen sich sowohl in Kombination mit der elektrischen Messtechnik, als auch bei alleinigem Einsatz.
New sensors for the detection of partial discharges (PDs) in high-voltage (HV) cable accessories are being de-veloped consisting of a fluorescent polymer optical fiber (F-POF) as sensing element. Depending on the fiber material F-POFs can be attached to and even integrated into the translucent silicone rubber insulation of HV cable terminations. As the embedment into the insulation material plays an important role, the sensor should not weaken the dielectric strength of the insulation material and should not be the origin of PD incidents. A sensor consisting of a commercial F-POF has been tested in the high-voltage lab regarding its PD detection ability un-der AC in comparison to a conventional electrical sensor. New silicone rubber F-POF (Si-F-POF) fiber models functionalized with coumarin dyes have been produced. The optical properties of these dye functionalized silox-anes are presented. These potential sensor fibers are highly flexible and might be embeddable at medium to high-voltage level. An additional way to further improve the level of PD light detection is to modify the translucent type of silicone rubber used in HV cable accessories in terms of optical transparency. In this context we present our first results of the optical and mechanical properties of new elastomeric transparent silicone materials specif-ically designed for the application as HV insulation materials in stress cones.
We present recent progress in our development of fibre-optic sensors for the detection of partial discharge (PD) in silicone cable accessories, based on detecting related low-level optical emission. We experimentally show that the sensitive optical detection of PD can dramatically enhance the performance of conventional electrical PD measurement in electromagnetically noisy environments, and that it can yield high sensitivity and specificity even when no synchronous electrical PD measurement is conducted. This is demonstrated using a real-scale model of a high voltage cable accessory with a surface-attached conventional thermoplastic fluorescent polymer optical fibre (F-POF) sensor. In order to increase light collection efficiency, as a prerequisite for a commercially competitive implementation using cost-efficient detectors, sensing fibres will have to be integrated into the silicone rubber insulation, close to the potential origin of PD-induced damage. This is the rationale for our efforts to develop elastomeric fluorescent sensing fibres, tailored to the requirements of the application. We discuss specific challenges to be tackled and report on the successful implementation of all-silicone rubber fluorescent POF, to our best knowledge for the first time. © (2015) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Organometallic oligoamides built from three to four ferrocene amino acid units (H-Fca-OH,1-amino-1'-ferrocene carboxylic acid) fold into hydrogen bonded secondary structures featuring eight-membered rings by cooperative hydrogen bonds. NMR studies and DFT calculations (CAM-B3LYP, LANL2DZ, IEFPCM (THF) reveal that the organometallic zigzag foldamer structures are highly resistant toward denaturation by hydrogen bond acceptors such as dimethyl sulfoxide and 2,4-lutidine. Replacing one ferrocene amino acid unit by the organic alpha-amino acid glycine at the C-terminal end (Fca goes to Gly) significantly destabilizes the secondary zigzag structure facilitating denaturation by DMSO. Highly stabilized ordered poly(Fca) architectures are very attractive for future applications of switchable hydrogen-bonded redox-active materials.
We present fundamentals for the selection of fluorescent dyes and show the challenges of the implementation of fluorescent dyes in silicone rubber materials for the production of fluorescent all-silicone rubber POF.
Optical methods and monitoring systems for the PD detection in GIS, GIL and oil-immersed type transformers have been demonstrated. Very recently these methods have been extended to the detection of PDs in solid insulation materials of cable accessories. This novel application in high-voltage (HV) cable terminations consists of integrated fiber-optic sensor which requires transparent insulation materials. Therefore, transparent silicone rubbers are considered as replacement material for currently used opaque elastomeric insulation material in stress cones of HV cable accessories. For this purpose a preliminary study on the long-term stability of two commercially available fully transparent silicone rubbers was performed. Accelerated thermal aging tests were carried out for 4 hours up to 100 hours at 200 °C under a normal air atmosphere and normal atmospheric pressure. The impact of thermal aging on the AC dielectric strength of the silicone samples was investigated and additionally the optical transmittance was determined using UV-Vis spectrophotometer. The investigation indicated that the dielectric strength value of the silicone samples was seriously reduced for long-term exposures to elevated temperatures. In addition, the UV-visible transmittance of thermally aged silicone samples was also decreased. The influence of these phenomena must be taken into account for the design of HV insulation materials, particularly under extremely high temperature operating conditions.
The mechanical and electrical properties of new transparent silicone materials modified with two fluorescent dyes were investigated by measuring stress-strain behaviour, electrical breakdown strength, capacity and dissipation factor, before and after thermal ageing, as well as electrical and optical partial discharges.
Mechanical properties of the new materials are comparable to the reference and the addition of dyes stabilises them against thermal ageing. All materials are equivalent in terms of breakdown strength and capacity. The added value of transparency and fluorescence make them suitable materials for novel diagnostic applications in HV cable accessories and insulators.
We present the production process and characterization of a fluorescent functionalized elastomeric polymer optical fiber (E-POF) consisting of a covalently linked interface between fiber core and fiber cladding. This all silicone rubber E-POF shows increased temperature stability and can be used for sensing applications. Due to the sophisticated production process surface roughness of the interface of fiber core - fiber cladding are even lower than of the thermoplastic tubing template. Total fiber lengths can be extended by a "chemical splicing" technique, allowing individual tailoring of fibers while maintaining sufficient elasticity under applied mechanical stress.