Research On State Assessment Method Based On EHV Power Grid Secondary Device

With the development of extra-high voltage power grid, there are more and moresecondary equipment in extra-high voltage power grid. A lot of secondary equipment are thecapable of self-checking. If time-based maintenance is continued to be applied to secondaryequipment, it is undesirable. Condition-based maintenance according to the practicaloperation should be carried out. That meets the development of power system. The key of theextra-high voltage power grid secondary equipment condition-based maintenance is scientificand reasonable state assessment based on extra-high voltage power grid secondary equipment.An effective state assessment method plays a key role for the extra-high voltage power gridsecondary equipment state assessment. In the thesis, state assessment method is in-depthstudied, which is based on extra-high voltage power grid secondary equipment. For this thesis,there is a certain practical significance to guide the state assessment of extra-high voltagepower grid secondary equipment.Some power system secondary equipment contents, which contain condition-basedmaintenance, condition monitoring and device self-diagnosis, are studied in this thesis.Though analyzing the related characteristics of extra-high voltage power grid secondaryequipment, the assessment method uses the self-checking messages, operation conditionmessage, hidden failures message as assessment data. For the extra-high voltage power gridsecondary equipment self-checking messages, the extra-high voltage power grid secondaryequipment state assessment is carried out through the fuzzy comprehensive evaluation method.For the extra-high voltage power grid secondary equipment operation condition message, theextra-high voltage power grid secondary equipment state assessment is carried out through theMarkov forecasting method. For the extra-high voltage power grid secondary equipmenthidden failures messages, the extra-high voltage power grid secondary equipment stateassessment is carried out through the hidden failures diagnosis. For the assessment results ofthe above three state assessment methods, the DS evidence theory is utilized to fuse it indecision making level.For every extra-high voltage power grid secondary equipment state assessment method,the thesis applies the appropriate example to analysis and calculation the methods. Thecomputed result shows that normal state reliability of information fusion state assessment ishigher than normal state reliability of single state assessment method. It shows that themethod is correct.Though the example analysising, when the assessment message of an extra-high voltagepower grid secondary equipment state assessment method is changed, it has greater impactthan the extra-high voltage power grid secondary equipment state assessment method based on information fusion. Though using the three assessment message, the extra-high voltagepower grid secondary equipment is synthetically and comprehensive assessment.