Research And Application Of TV Multi-point Grounding Fault Monitoring

To ensure that the voltage transformer transforming the primary voltage accurately pass to the secondary side, and to prevent a secondary breakdown, causing personal injury and equipment damage, TV on the secondary side must have a ground point. But TV secondary circuit multi-point grounding may cause TV neutral point voltage phase shift, which would impact the amplitude and phase of phase voltage and zero-sequence voltage, resulting from the protection, zero sequence directional protection malfunction or refuse to move. In order to detect and deal with TV multi-point grounding fault timely, reduce risk and difficulty of the work, improve the safety and reliability of economic operation of the system, a TV multi-point grounding line monitoring devicewas decided to develop.Researching TV ground fault Phenomenon and monitoring methods points. Firstly, analyzing the TV multi-point grounding fault phenomena and changes in the TV multi-point grounding fault various data. Secondly, researching several TV multi-point ground fault detection methods which more applied: resistance method, signal injection method and unbalanced load current law. Finally, the TV multi-point ground fault alarm criterionwas developed.Development of TV multi-point grounding line monitoring device. Based unbalanced load current law a set of TV multi-point ground fault line monitoring deviceswere developed, a detailed study of the working principle of the device, the software and hardware design and its features, safety and possible adverse effects were analyzed; In addition, a new opening current transformer was developed.TV ground fault monitoring device testing. Through the field tests and real job site testing, the effectiveness and practicality of the TV ground fault monitoring device developed were tested, fully meeting the site operating needs; and also demonstratingthat the proposed N600 Theoretical grounding multiple harmonic current detection was useful and necessary.