Switching transients produce steep fronted waves (prestrikes or restrikes) which reach the machine terminals producing severe dielectric stresses in the winding insulation. The object of this study is to develop computer models for calculating the surge distribution in the winding during switching transients as well as to obtain a machine terminal representation. Beginning with a very simple model valid for very short periods of time, the computer models are extended and finally a full machine winding model is presented. The computer models developed cover a broad time and frequency range and they are based on multiconductor transmission line theory. Several phenomena like the flux penetration into the iron and the stator inter-coil coupling are studied and incorporated into the solutions. The thesis also describes several application studies using the computer models developed. The studies include a sensitivity analysis from which guidelines for reducing the dielectric stresses in the winding insulation are suggested. Using convolution techniques and measurements on machine terminals, a technique for a better assessment of the dielectric stresses in the coils during real switching transients is presented. Finally, the computer results are supported by a comprehensive set of measurements carried out on a 6.6 KV. 1690 KW. machine winding
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:521481 |
| Date | January 1989 |
| Creators | Guardado, J. L. |
| Publisher | University of Manchester |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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