Research And Implemente Of Partial Discharge Location System

Power transformer is one of the most important instruments in power system, by whose safety running the credibility of power supply directly will be influenced. Partial discharge is the main reason for insulation ageing of high-voltage electrical equipment, and also an important symptom and manifestation of insulation ageing. So, for keeping power transformer normal, it is crucial to monitor the discharge location and electric capacity effectively and precisely. Based on analyzing the development of discharge location technology, this paper pays attention to the study for the discharge resource location and de-noise for partial discharge signal, and proposes approach to solve the two problems and development of the software platform. The main contributions can be summarized as follows:Firstly, partial discharge signal de-noise methods are studied, and multi-resolution EMD is employed to remove the noise of the signal collected in the field. Introducing multi-resolution to traditional EMD, multi-resolution EMD successfully solves two problems of traditional EMD:modal mixture and computation quantity. This method can effectively extract partial discharge signal from the site signal and provide a basis for the discharge resource location. The result shows that the proposed approach is effective.To calculate discharge source, a new optimization algorithm, gradient shrink algorithm is applied and derived. Gradient shrink algorithm is a new optimization algorithm for unconstrained functions, and it is expected to cause the Euclidean norm of the gradient of objective function gradually shrinks to zero in order to minimize the object. Field result shows that gradient shrink algorithm can effectively locate discharge source and is greatly superior to traditional methods.Using the two methods above, this paper developes a soft system of ultrasonic locating based on virtual instrument. The system based on the graphical programming language LabVIEW can implement several functions such as filtering the on-line detection data, locating discharge source and so on, and provide an effective platform for the location of discharge source in power transformer.