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.

Method and directional element for fault direction determination in a capacitance-compensated line

Abstract: An electrical power system includes a transmission line for transmitting electrical power, series capacitance compensation series-coupled to the transmission line adjacent one end thereof, where the series compensation includes a capacitance having a value (−j X CAP ), and a protective relay at the one end of the transmission line for monitoring line voltages and line currents on the transmission line. Upon sensing a fault, an impedance Z of the line is calculated based on the monitored line voltages and line currents. The calculated impedance Z is adjusted according to the value of the capacitance of the series compensation (−j X CAP ) to result in a modified impedance Z MOD , and the phasor angle Of Z MOD is examined to determine the direction of the sensed fault. The fault is in a first direction if the phasor angle is between X and X+180 degrees and is in a second direction opposite the first direction if the phasor angle is between X+180 and X+360 degrees.

Utilization of extended firewall for object-oriented regression testing

Abstract: A testing firewall involves identifying various components that are dependent upon changed elements, but are just one level away from the modified elements. This paper investigates situations when data flow paths are longer, and the mechanism of thorough testing of components one level away from the changed elements may not detect certain regression faults caused by the change; this research has led to the notion of an extended firewall that takes these longer data paths into account. Empirical studies are reported that show the extent to which an extended firewall can detect more faults and how much more testing is required to achieve this increased detection.

Gantry-Tau A New Three Degrees of Freedom Parallel Kinematic Robot

Abstract: In the last decades, an increasing attention has been paid to the study of different parallel structure mechanisms and their applications, mainly triggered by Stewart that presented an aircraft simulator system. Parallel structure features provide big advantages in potential applications. For example, parallel robots may give higher speed and acceleration, higher static and dynamic accuracy and higher stiffness than what is possible with the industrial robots used today. A typical limitation with many of the paral-lel structures is that their workspace is small com-pared to the serial structures. This paper presents a new parallel structure, the Gantry-Tau, which pro-vides 3 degrees of freedom (DOF) translational mo-tion with a large workspace. The structure of the ro-bot is patented by ABB. The Gantry-Tau robot is a six link parallel kinematic structure with the links configured according to 3-2-1. The 3-2-1 notation refers to how many links form each resulting kine-matic cluster of the robot. Orientational DOF of the robot could be provided by a decoupled system. For a conventional 3 DOF serial gantry ro-bot two of the actuators contribute to the moving mass. The Gantry-Tau can be constructed with ex-ceptionally low moving mass since the actuators are stationary and the structure has inherently high stiff-ness. The structure is thus ideal for many applications with demands on high accelerations, for instance for the pick and place operations. The nominal inverse and direct kinematics of the structure are developed and optimization is used to find a construction of Gantry-Tau with maximum workspace volume.