Transient Analyze Of Stator’s Internal Faults In Lap Winding Hydro-generato

There has been a rapid expansion of our national economy, as well as electricityconsumption and the capacity of generator. The malfunction of generator happensmore possiblely than before. Generator is one of most important parts of powersystem, and its operation stability gets more and more public attention. Stator’sInternal Fault is one of the most common faults, which may leads many seriousconsequences.Firstly, the types of Hydro-generator stator’s internal faults are analysed in thispaper. The program for stator’s internal faults statistics is compiled in VB6.0basedon the wave winding and lap winding structure features, taking a generatorrespectively for. Users just need to type the basic parameters of generator into theinterface, and then the modality, the position and the number of short-circuit faultsare automatically summarized and output. The interactive interface easy to use withVB6.0is achieved, which can lay the foundation for the following work of stator’sinternal faults classification analysis.Secondly, based on the multi-loop theory, the mathematical model ofsynchronous is established in this article, which can roundly emulate the current andits waveform of stator’s internal faults. The running condition of lap windinghydro-generator in the case of grid-connection with no load is calculated in this paper.When its stator’s internal short-circuit fault happens, including inter-turn short circuitof same branch, inter-turn short circuit of different branches, and interphase shortcircuit, the current of every branch in the generator is calaulated. After analyzing thedynamic changes of the current in each branch, the laws governing the current of thegenerator turn to turn short-circuit is investigated, which shows that ratio of windingand the position of internal faults have great influence on the current. The currentdata we get in this part provides a sufficient theoretical basis for main protection configuration scheme.Finally, the theory and performance of four main protections of generator isresearched and compared clearly. For the Hydro-generator with lap winding assimulation example in this article, using the results above, the current we need ispeocessed and extracted to be used in the sensitivity setting calculation. Feasibleprotection combining schemes are presented to check sensitivity. Then an optimalmain protection scheme is decided after comprehensive consideration.