Investigation On The Portable Instrument For On-line Monitoring Leakage Current Of MOA

By applying the MOA on-line monitoring technology, we can understand the performance condition of MOA at any time without unnecessary power-cut-off overhaul. Thus we can detect the abnormal phenomena and hidden accidents of MOA in time, take measures in advance to prevent the accident from getting worse and to avoid the economic loss resulted from the accident. In this thesis, a portable instrument for on-line monitoring leakage current of MOA was developed. The contents are listed below:1. Investigating the relationship between the resistive component of the fundamental frequency current and that of the 3rd harmonic current by experimentation with real MOVs.2. Establishing and analyzing the mathematical model of MOA,then developing a portable instrument based on the Digital Waveform Analysis method for on-line monitoring leakage current of MOA. This instrument can on-line monitor all kinds of parameters of MOA in serve. It can also eliminate the interference among different phases.3. Analyzing all potential errors and electromagnetic interference entering the instrument while it is working and taking measures to reduce the influence of them. Some experiments are done to test the accuracy and stability of the instrument. The results indicated that it can work accurately and reliably.4. On the foundation of the successful Digital Waveform Analysis method, some valuable explorations were made and a new idea about MOA on-line monitoring was presented in this thesis. A Virtual Instrument based on the new idea was established and was proved to have some significance in improving MOA on-line technology in the future.