High voltage capacitors designed to avoid catastrophic failure modes
A major concern in the operation of high voltage capacitors is the failure mode at end of life. While progress has been made in this area at lower voltages, little has changed for high current capacitors operating above 30 kV in steady state and pulsed power applications. Based on a new development at Maxwell Energy Products, Inc., it is now possible to build capacitors that can operate with a high degree of safety at high voltages. The capacitors reach the normal end of life, while avoiding the catastrophic failures, collateral damage, and unscheduled maintenance, associated with the normal failure mode of today's high voltage capacitors. This paper discusses the problem, capacitor failure modes, capacitor designs and describes a solution to the problem of catastrophic high voltage capacitor failures.
Influence factors for the self-healing of metallized polypropylene capacitors
After the local breakdown of the metallized film, the self-healing of the capacitor is influenced by several factors, including the capacitance of metallized capacitor, pressure, as well as the applied voltage. In this paper, they are investigated fundamentally in reference to their influence towards the insulation recovery of the metallized polypropylene. Single metallized polypropylene film and metallized film capacitors are used as experimental samples to study the effect of these factors after local breakdown of the film under the conditions of impregnation and nonimpregnation. The results show that, these factors impose their influences via the infusion energy passing the breakdown path. It is also found that excess the infusion energy will be adverse to the self-healing of metallized polypropylene capacitors.
Numerical Simulation for Natural State of Two-Phase Liquid Dominated Geothermal Reservoir with Steam Cap Underlying Brine Reservoir
Hydrothermal reservoir which liquid-dominated hydrothermal reservoir is a type of geothermal reservoir that most widely used for power plant. The exploitation of mass and heat from the geothermal fluid will decrease the pressure in the reservoir over time. Therefore the pressure drop in the reservoir will have an impact on the formation of boiling zones or boiling will increase. The impacts are an increase in the fraction of steam, dryness, in the reservoir and with good vertical permeability will form a steam cap underlying the brine reservoir. The two- phase liquid dominated reservoir is sensitive to the porosity and difficult to assign average properties of the entire reservoir when there is boiling zone in some area of the reservoir. These paper showed successful development of two-phase liquid dominated geothermal reservoir and discussed the formation of steam cap above brine reservoir through numerical simulation for state natural conditions. The natural state modeling in steam cap shows a match with the conceptual model of the vapor-dominated developed. These paper also proofed the presence of transition zone, boiling zone, between steam cap and brine reservoir.