Transformers insulants

Approximately 50% of the demand for tetrachloroethylene is in the dry-cleaning industry where about 80% of all dry cleaners use it as their primary cleaning agent. Use as a feedstock for chlorofluorocarbon production accounts for 30% of current demand. Metal cleaning and miscellaneous appHcations represent 12 and 8% of demand, respectively. The miscellaneous appHcations include such varied uses as transformer insulating fluid, chemical maskant formulations, and as a process solvent for desulfurizing coal. 

Recommended apphcations include transformers, insulators, bushings, wire and cable, generators, motors and switchgear, additives for adhesives, vinyl stabilization, and as viscosity depressants. 

Impeller wheels for regenerative pumps, pump rotors, laundry system wheels, submersible pump insulation, dry transformer insulation. .. 

Hartford Steam Boiler Inspection and Insurance Company (HSB) insures distribution transformers for power generation utility companies. The cost to HSB when an insured transformer fails often exceeds a million dollars. The possibility of losses of this magnitude has given HSB the incentive to develop a transformer fault early detection and diagnosis program, based on chemical analysis of the transformer insulating oil. 

Maximum voltage of current transformer Rated power of current transformer Insulation voltage of current transformer (windings to earth)... 

Jada, A., et al.. Adsorption and surface properties of silica with transformer insulating oils. Fuel, 81, 1227. 2002. 

P. A. von Guggenberg, Application of Interdigital Dielectrometry to Moisture and Double Layer Measurements in Transformer Insulation, Ph.D. Thesis, Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, 1993. 

PCB/transformer insulation reinforced (prim-sec), basic (prim-grd), other Wire separation (prim-sec) distance or thickness (2 layers) or 3 layers, or other ... 

The key benefits of the vapor drying of power transformer insulation are as follows ... 

Feather LE. Drying and oil impregnation of power transformer insulation. Proc. h Electrical Insulation Conf. New York, Paper 32C3-8, 1965, pp 65-69. 

An essential character of a process, system, or equipment that makes it without or very low in hazard or risk. For example, the use of non-combustible liquids instead of combustible liquids for an operation (e.g., transformer insulating oil) makes a process inherently safer by removing the hazard of fire should the liquid contact an ignition source. 

In the seventies, it has been found that the transformers insulated with oil and built since the beginning of the 50 were often contaminated with PCB. According to the inventory of Hydro-Quebec, we estimate that 10 to 15 % of these transformers would have concentrations of more than 50 ppm of PCB, and less than a 1 % concentrations of more than 500 ppm. It is why the public, and particularly the workers in the electrical industry and the firemen, fear the consequence of a fire with such equipment. Is there a risk with the presence of PCDF during the combustion of these contaminated oils, and can we estimate it ... 

The real world test parameters discussed above have been incorporated into the fire hazard assessment model used by UL (Webber 1983) to determine the compliance of transformer fluids with section 450.23 of the National Electrical Code. In order to be compliant with the code, transformers insulated with less-flammable liquids are permitted to be installed without a vault in Type I and Type II buildings of approved noncombustible materials in areas in which no combustible materials are stored, provided there is a liquid confinement area, the liquid has a fire point of not less than 300 C and the installation complies with all restrictions provided for in the listing of the liquid. UL has identified the need for pressure relief devices and current limiting fusing to limit the effect of possible high current arcing faults. 

Energization Charging in Transformer Insulation," M.S. Thesis, Dept, of Electrical Engineering, M.I.T., Cambridge, MA. 

Outside of the drinks industry, PET is often used for photographic film, recording tape, flexible printed circuit boards, transformer insulation and transparent stationery. 

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