Research On Audible Discharging Noise Of Transmission Lines Monitoring And Analytic System Based On 1/3 Octave Algorithm

In order to adapt to the rapid development of economic society and meet the rapid growth of power demand, using the higher voltage level of transmission network has become more and more universal. It is not only brings us convenience, the attendant problems also become increasingly prominent. Among them, the corona discharge phenomenon occurred from the high voltage transmission lines is not uncommon, and the harm caused by it can be described as not be overlooked.With the further improvement of transmission lines voltage, the phenomenon of partial discharge will happen inevitably, and the corona discharge is one of kinds of it, it will also bring a series of harmful consequences(audible noise). By developing the transmission lines reliability monitoring system based on technique of audible discharge noise information acquisition and analysis, the discharge noise signal is extracted from the environment and electrical noise, so we can use it to analyses the noise intensity and noise spectrum, and to evaluate the transmission lines status. It makes sense to operate with the transmission lines healthily and stably.The domestic and foreign research works, presently, for audible noise of transmission line have been harvested. Abroad in 1960 s have begun to study this theme, they have focused on its production mechanism, acoustic characteristics, testing methods, noise reduction measures and other aspects of the content. It is relatively far behind them in our country, in the 90 s of the last century, we began to researched the field measurements and noise reduction measures of audible noise in transmission lines.At present, in order to eliminate the discharging noise of high voltage transmission lines, the related research at home and abroad is focused on the establishment of the discharging noise prediction model to guide the laying of transmission lines. In view of the present situation, this paper designs experiments which reflect the spectrum characteristics of the audible discharging noise under different discharge state, and summaries the corresponding relationship between the spectrum characteristics and the fault condition of the transmission lines. A 1/3 octave algorithm is put forward here to analyze and deal with the noise data, and the different discharge conditions is characterized by the sound pressure level with a range of 8kHz. A transmission lines audible noise discharge monitoring system is designed, whose feasibility and effectiveness are verified through experiments. In order to determine the discharge of severity, a discharging threshold of the experimental platform is set up, and then the health status of the transmission line is reflected.The main contents of this paper are summarized as follows:(1) We analyzed the serious phenomenon of audible noise from transmission lines caused by corona discharge, and summarized from the domestic and foreign scholar’s research results, then illustrated the significance of the audible noise detection.(2) Consulted and explained some basic theoretical knowledge of audible noise and the algorithm theory used in this monitoring system was introduced significantly.(3) The audible noise in 8 kHz frequency curve we got by summing up and analyzing data is stable and is suitably used to detecting and analysis of transmission lines health status.(4) Analyzed the existing noise detection theory and the actual situation and the requirement from transmission lines, and completed the design of monitoring system software and hardware to realize the monitoring of audible noise.(5) We used the monitoring system to do lots of experiments to compare and analyze the earlier data used by pickups, and draw the corresponding conclusions at last.After the monitoring methods of the audible noise from transmission lines were summarized and analyzed, this article put forward the method of using 1/3 octave spectrum analysis algorithm to completed the design and implementation of the real-time monitoring of the audible noise monitoring device which can indicate the relevant staff to analysis of the health status timely and to take measures. The device can effectively reduce the construction cost of the power network in China, as well as to ensure its stable operation.