| It is well known that the power transformer is one of the most important equipments in power system and its operation condition greatly influences the safety of power system. With the increasing of power capacity and voltage rate, the conventional prevention maintenance was unable to fulfill all of needs. As a result, Corresponding timely and effective condition-based maintenance (CBM) is introduced and developed.CBM is the future of insulation condition assessment and predictive maintenance. CBM of power transformer can monitor the operating conditions while the transformer need not be laid off. According to the real-time operation parameters, on-line monitoring of power transformer makes the possibility of extending their operating time, reducing the disk of expensive failures and providing the potential in changing the maintenance strategy.The basis of a successful application of CBM lies in obtaining information of transformers by some advanced digital devices. In this thesis, the insulation failures characteristics of oil-filled transformer are analyzed firstly. Then the existing measurement techniques used for on-line monitoring are compared each other in accordance with the practicability and the validity. In the last, Dissolved Gas Analysis (DGA), as one of the most useful techniques to detect incipient faults, was chosen to realize the insulation condition monitoring for power transformers. Based on DGA, an oil chromatograph on-line monitoring system for transformer is developed. The system mainly measures the volume content and trend of the fault-related gases include H2, CO, CH4, C2H2, C2H4, and C2H6.In this thesis, the design ideas and the real ization of the on-line monitoring system are introduced in detail, including the whole structure, the principles of main modules, and the design of the hardware and software. In the end, the performances of the whole device are tested and the errors are analyzed. |
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