Fault Clearing Overvoltages on Long Transformer Terminated Lines
The results of Transient Network Analyzer (TNA) studies evaluating the feasibility of low-side switching long transformer terminated lines is reported. It is shown that overvoltages following line dropping and fault clearing can severely stress surge arresters and circuit brtakers exceeding capabilities specified in ANSI standards. These overvoltages are often not carefully considered in design studies, since the available literature on low-side switching of EHV transmission lines primarily deals with energizing the line and transformer.1,2,3,4
Electromagnetic transient analysis in EHV power networks
Following an outline of electromagnetic transients in high-voltage power networks, together with their principal implications in relation to system overvoltages and the switching duty imposed on circuit-breakers, the paper develops a broad review of the now numerous analysis formulations and computer solution methods in this area of applied analysis in power systems. The perspective is one which extends from the earliest developments in surge analysis to the most recent proposals from current research. In particular, it includes the main forms of traveling-wave methods, Bergeron analysis, time-convolution schemes, and the recently derived methods in which the z transform has a unique part.
Neotectonic rotations in the Orava-Nowy Targ Intramontane Basin (Western Carpathians): An integrated palaeomagnetic and fractured clasts study
Abstract The objectives of this contribution are: (1) to promote the application of fractured clasts analysis in conglomerates for regional stress reconstructions and (2) to advance reconstruction of the Western Carpathians structural development. Our results show that the Neogene fill of the Orava-Nowy Targ Intramontane Basin underwent CCW rotation of about 30°. We infer that the rotation terminated after 8 Ma and was related to shift along NW-SE to NNW-SSE trending faults at the NE termination of the sinistral Mur-Žilina Fault Zone. Our results show that, fractured clasts analysis can be good tool for regional tectonic reconstructions. The tool is especially useful when other tectonic tools are scarce or absent. Results of our palaeomagnetic study and fractured clasts analysis verify and supplement each others. In the studied case, palaeomagnetic results allow to distinguish between regional stress field rotation and rotation of the Orava-Nowy Targ Basin Neogene fill, whereas, results of fractured clast analysis help to constrain the age of rotation.