The Development Of A Dissipation Factor Measurement System Based On The Quasi-Synchronous Caculation Method

With the development of the national economy, electric power is more and more required by different sectors. Electric power networks have been enlarged steadily. How to assure the safety operation has been becoming the key issue of the electric power system. Therefore, an applicable detection method should be adopted to know well the actual operating situations of the networks'equipments, so that they can be managed and maintained properly.The insulation failure is the main accident of electric power networks'equipments, so their detection is of great significance. Measurement of dissipation factor is a highly sensitive examination item of electrical insulation examination, it can detect the partial deficiency of electrical devices such as wholly insulation damping,deterioration and partical discharge, thus it is of great importance to accurately measure the dissipation facror. Based on the quasi-synchronous calculation method, the author has developed a dissipation factor measuring system.Firstly, the harmonic method is studied to develop the measuring technology of the dissipation facror and the calculating formula of the dissipation facror using quasi-synchronous method is derived out. Moreover, the validity of the method is studied by computer simulation. Secondly, extraction circuit of the current and voltage is designed and the two channels synchronous data acquisition circuit board is developped. Finally, according to the result of theoretical study, a dielectric loss calculating software using the quasi-synchronous method is developed and the simulative experiment is studied.By the computer-aided analysis, the paper finds that this method, using the quasi-synchronous sampling harmonic analysis to measure the dissipation factor, has the advantages of high accuracy and better anti-interference characters. This is also verified by the practical measurement results which indicate that the measuring precision of the measuring system can reach 0.0001, and it satisfies fully the requirements of the dissipation factor measurement in field.