Research On Closing States Of High Voltage Disconnectors Based On Vibration Analysis

As the most widely high voltage equipment in power systems,the monitor,prevention,analysis and exclusion of high voltage disconnectors' faults have attracted wide concerns to ensure the safe,reliable operation.It is particularly important to monitor the closing states of disconnectors.During the closing of the high-voltage disconnectors,the collision between mechanical components will cause vibration,which contains lots of equipment status information.Through the analysis,the internal components of the disconnector and closing states can be effectively reflected,to monitor the existence of mechanical failure and safety hazards.The vibration analysis is a non-invasive measurement method,which has the advantages of not affecting the operation of the disconnector and being less affected by the electromagnetic field.Firstly,the current methods of judging the closing states of high-voltage disconnectors were introduced in this thesis.The methods for identifying modal parameters in time domain and frequency domain were studied,especially the polynomial curve fitting method.Secondly,the 3D models of GW4D-126(G·W)high voltage disconnectros were built based on SolidWorks and imported into ANSYS Workbench to perform pre-stress modal analysis,so as to analysis the frequency and mode shape of disconnectors in different closing states.And then,the modal experiments using hammers were conducted.In the test,a portable force hammer was used to strike the conductive arm on the same point several times,to give an excitation signal.Laser vibrometer and acceleration sensor were used to obtain the vibration signal at the same time.The experimental data with the correlation coefficient greater than 0.8 is selected and saved for the next step--modal parameter identification.Finally,the algorithm of orthogonal polynomial was realized in MATLAB to verify its accuracy and feasibility.Meanwhile,data preprocessing,filtering and other data processes were introduced.The modal parameters were obtained by modal parameter identification based on the orthogonal polynomial method in MATLAB.Comparing with the simulation results,the feasibility of the vibration analysis method was verified in the field of distinguishing disconnectos' closing states.