Short-circuit Interruption Tests Research Articles

Development of a high‐speed electromagnetic repulsion mechanism for high‐voltage vacuum circuit breakers

AbstractThis paper presents a design and testing of a new high‐speed electromagnetic driving mechanism for a high‐voltage vacuum circuit breaker (VCB). This mechanism is based on a high‐speed electromagnetic repulsion and a permanent magnet spring (PMS). This PMS is introduced instead of the conventional disk spring due to its low spring energy and more suitable force characteristics for VCB application. The PMS has been optimally designed by the 3D nonlinear finite‐elements magnetic field analysis and investigated its internal friction and eddy‐current effect. Furthermore, we calculated the dynamic of this mechanism coupling with the electromagnetic field and circuit analysis, in order to satisfy the operating characteristics—contact velocity, response time, and so on, required for the high‐speed VCB. A prototype VCB, which was built based on the above analysis, shows sufficient operating performance. Finally, the short circuit interruption tests were carried out with this prototype breaker, and we have been able to verify its satisfying performance. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 163(1): 34–40, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20398

Development of a High-speed Electromagnetic Repulsion Mechanism for High-voltage Vacuum Circuit Breakers

This paper presents a design and testing of a new high-speed electromagnetic driving mechanism for a high-voltage vacuum circuit breaker (VCB). This mechanism is based on a high-speed electromagnetic repulsion and a permanent magnet spring (PMS). This PMS is introduced instead of the conventional disk spring due to its low spring energy and more suitable force characteristics for VCB application. The PMS has been optimally designed by the 3d non-linear finite-elements magnetic field analysis and investigated its internal friction and eddy-current effect. Furthermore, we calculated the dynamic of this mechanism coupling with the electromagnetic field and circuit analysis, in order to satisfy the operating characteristics—contact velocity, response time and so on, required for the high-speed VCB. A prototype VCB, which was built based on the above analysis shows sufficient operating performance. Finally, the short circuit interruption tests were carried out with this prototype breaker, and we have been able to verify its satisfying performance.

Equivalence Between Direct and Synthetic Short-Circuit Interruption Tests on HV Circuit Breakers

Verified thermal models of the circuit breaker arc resistance were used to evaluate the equivalence lence between direct and corresponding currenttioninjec- ion synthetic circuits during short-circuit intetionrup- ion tests. It was observed that it is not sufficient for both circuits to produce the same prospective current ent stress and recovery voltage envelope but that they must have the same topology of their voltage branch although the values of their inductance can be quite different.

Equivalence Between Direct and Synthetic Short-Circuit Interruption Tests on HV Circuit Breakers

Equivalence Between Direct and Synthetic Short-Circuit Interruption Tests on HV Circuit Breakers

Design Considerations in Medium Voltage Starters for Underwriters' Laboratories' Standards

The main design and test requirements for motor controllers in the 2200 V to 5000 V range as given in Underwriters' Laboratories Standard UL 347 are outlined. The ways in which these requirements are met in a typical starter are described. Design requirements are reviewed on guarding live parts, grounding, wiring space, isolating means, and interlocking. The extensive performance test program specified in the standard is described, including operating tests, short- time capability tests, temperature tests, dielectric tests, overload tests, and short-circuit interruption tests.