Probabilistic Risk Analysis And Control Of Power Transformer Field Maintenance Work

With the rapidly development of extra-high voltage and large-scale power grid, the operation risk of power grid is growing bigger. Also, the safety and stabilization issue of electric power system has drawn widly attention. Power transformer, of which the running condition has direct effect on the safety and reliablility of electric power system, is one of the core equipment in power system. Different kind of risk exists in the procedure of power transformer field maintenance work, which brings certain hidden danger to the operation. To make sure that the power transformer field maintenance work can be safe, the study on risk analysis and risk control of power transformer field maintenance work has great significance.Fistly, this thesis analyses the connotation of the power transformer field maintenance work risk and classfies the risk combining risk management theory. The characteristic of the risk during power transformer field maintenance work is analysed.The risk exsiting in the work is identified from four aspects:the quality of people, equipment, working environment, field management.The risk factors identification table is established based on the hall three-dimensional risk analysis model.Further more, based on the overall risk identification and the probabilistic risk assessment theory, the fault tree model of transformer field maintenance work is established. Also, the bayesian network of transformer field maintenance work based on the fault tree model is established. Associated with expert judgment, the Delphi method is used to evaluate the probability of transformer field maintenance work risk with the bayesian network. The final risk quantization result is obtained combined with the fuzzy comprehensive evaluation of risk consequence, then the final risk quantization result is evaluated.At last, the security barrier model is established. The measure of risk control is formulated based on the security barrier which is built from equipment-technology barrier and organization-management barrier, thus the risks of transformer field maintenance work can be realized.Combining the project of "Study on field work risk identification and monitoring system"from the maintenance filiale of electric power company in H province, taking the example of500kV main transformer minor repair work, of which the systematic risk identifacation, risk evaluation and risk control are carried out. The result shows that these methods are effective and scientific.