Analysis Of Basic Earthing Methods Andapplications Of Zero-sequence Current Protection In Urban Distribution Network

Earthing methods of Power System related to technical, economic, security and other aspects of the comprehensive Problem,and also the entire power system reliability, personal security, insulation levels, protective relaying, communications interference and grounding devices。With the development of power, power density increases, therefore the types of 10kV feeder ground fault are more,and more complex and also the protection of the phenomenon of incorrect action more prominent, seriously affecting the 10kV power supply system reliability.For the above, the author through years of historical data on the substation, protection configuration, protection setting, zero-sequence CT selection, zero-sequence induction CT study installation from ground zero-sequence current in a different way of principle and characteristic,analysis of zero sequence protection is not correct the underlying causes of action, summarized the field of zero sequence current protection factors, respectively, by the arc suppression coil neutral grounding and via low resistance grounding and the way of improved field application put forward their own views.Among the arc suppression coil grounding, through the author in the case that the process of using the above configuration the links between the various parts of the scene, the construction quality of points to note; in the grounding via low resistance, the site focuses on the specific application of its detailed overview of small resistance grounding protection, zero sequence protection configuration and setting the scene, combined with practical examples of Dongguan Power Supply Bureau to come to the grounding via low resistance mode, the rational application of 10kV System Protection mode。Finally, the zero-sequence current transformer from the structure, the installation process to improve performance and accuracy on the optimal way, and that the authorities zero sequence current in the low resistance of the protection of the application needs to be further problems.