ABB Ltd

About: ABB Ltd is a company organization based out in Zurich, Switzerland. It is known for research contribution in the topics: Voltage & Signal. The organization has 6222 authors who have published 6852 publications receiving 83994 citations.

High resistance ground fault protection

Abstract: A protection device for high resistance ground faults in a power network according to the invention has a fault detection principle which is based on an indirect study of non-harmonic frequency components of the phase currents. When such a fault has occurred, a considerable change of the energy contents of these frequencies arises. This change can be detected by a device according to the invention. If by comparison (4e) between digitized input signals (I') and a harmonic Fourier model (4d) of the same signals, i.e. generation of the residuals of the system, it is found that a difference exists, and if the corre-sponding loss function VN (4f) for a certain time exceeds a lower limit value - all on condition that a zero sequence current (Io) exists - then there is a high resistance ground fault on any of the phases of the network. (Figure 2)

Fractography of unfilled and particulate-filled epoxy resins

Abstract: The objective of this work was to analyse and understand the types of fracture surface morphology found in unfilled and particulate-filled epoxy resins in the light of the thermomechanical history of the specimen (loading rate or duration of loading, temperature, strain at break). Short-term tensile tests and long-term creep tests were conducted at four different temperatures. The fracture surface features were analysed using the scanning electron and optical microscopes and, where suitable, an image analyser. In order to correlate these morphologies with certain regimes of crack velocity, fracture mechanics tests were also conducted, varying the crack speed between 10−7 and 102 m sec−1. In the case of the filled resin, the lifetime under static loading is governed by a phase of slow, sub-critical crack growth which is manifested by resin-particle debonding. Thereafter, the crack accelerates and finally may reach terminal velocities depending on the amount of stored elastic energy available at the moment of fracture.

Apparatus and method for storing thermal energy and generating electricity

Abstract: Because the efficiency of the thermal energy storage technology is inherently restricted, its beneficial use is limited to very particular economic boundary conditions, i.e. a large difference between the value of electricity going into the unit and the value of electricity coming out of the unit. With the reduction in wind power equipment prices and the cost of fossil fuels and/or their combustion products this is occasionally the case for wind power. Wind is a free fuel and the value of wind power when there is too little load demand is essentially zero, and the value of wind power when there is demand is considerable indeed. Under these circumstances, a combination of electrothermal energy storage and combustion of (fossil) fuels as an auxiliary heat source provides for a cost efficient system for storing energy and an economical way of generating electricity.

A life cycle management system for intelligent electronic devices

Abstract: This invention relates to the Life Cycle Management System for distributed Intelligent Electronic Devices (IED) starting from the design phase to the end of service phase. Hence, it caters to the needs from installation via engineering, installation/commissioning phases, until asset management and remote service support of the devices during the operational phase The increasing decentralization of the involved components via networks, especially via the Internet, is a key criterion and needs to be addressed by the life cycle management. The added value for the customer grows disproportionately with the degree of integration of multiple independent software components into a complex and often highly distributed control system. The architecture of today's control systems must be sufficiently flexible to allow customers to regard their plant components from various locations. Additionally, the stability, security and maintainability of such a system is strongly dependent on the homogeneity and interoperability of all involved components.

Fuel cell system power control method and system

Abstract: A fuel cell (10’) is placed in parallel with a battery (14’) via a mechanical switch. The voltage is held nearly constant by the battery (14’) and the power flow is controlled by adjusting the fuel cell (10’) operating parameters (such as temperature or air flow) and by opening and closing the mechanical switch. The result is a system that operates at nearly constant voltage without the need for an expensive power conditioning system. The output of the system can then be processed via a traditional conditioning system such as an inverter or dc-to-dc converter without the need for a wide range of input operating voltages. This reduces the cost and size of the fuel cell (10’) power conditioning system.