| Oil-paper insulation is still the best choice for the main insulation structure of large power transformers in power systems at this stage,and its insulation state will largely affect the electrical life and mechanical life of the transformer.In the long-term work process,temperature and moisture are the most important affect factors,the insulation and mechanical properties of oil-paper insulation gradually decline and eventually reach the end of life.Therefore,the way to determine the deterioration state of oil-paper insulation has important economic and social significance.In order to achieve an accurate assessmenl of the insulation status of oil-immersed transformers,this paper combines the actual operation of oil-paper insulated power transformers,and studies the oil-paper insulated equipment of different states and different manufacturers to achieve a comprehensive assessment of the transformer insulation status.By analyzing the change law of characteristic parameters of transformers of different families.it is found that the impact of different transformer manufacturers is far less than the impact of different operating conditions.A large number of frequency domain dielectric response experiments were carried out on the transformer oil-paper insulation equipment on site,and based on the dielectric polarization theory,the aging characteristics used to characterize the insulation state of the oil-paper insulation equipment were extracted from the frequency domain dielectric response experimental results.Finally,it studies the statbe evaluation method that integrates electrical,oil and dielectric response,and proposes a practical evaluation system for oil-paper insulation equipment.The comprehensive evaluation system of oil-paper insulated power equipment proposed in this paper provides a reliable decision-making aid for the state maintenance of the power system and improves the operational reliability of power equipment. |
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