Research On Key Technology For The Device Detecting Grounding Lines In Distribution Network

Power grid accidents of closing transmission lines with ground wire are still occurred inrecent years, and the consequences of these accidents are very serious. At present, inspectionsof ground wires in the process of distribution network operation are mainly completed byartificial, and the artificial leak or removing of the ground wires is still existed possibly. Theline maintenance of distribution network is usually with big quantity, wide coverage, sitediversity, and field workers’ requirements of ground wire detecting device is accurate,flexible and lightweight. Therefore, the development of intelligent ground wire detectingdevice which is suitable to distribution network is extremely necessary. After the completionof maintenance work of operation personnel and before the electricity transmission ofconverting station, can utilize this device to detecting whether the ground wires or shortcircuit wires of distribution lines exist or be removed. Currently, there has not such devicescapable of detecting ground wires in the market.Firstly, through field research site, this paper analysis grounding problems. Taking intoaccount the distribution transformers, joint telegraph poles and other factors impact on thedetection, this paper builds a electromagnetic transient simulation model of simulanttransmission lines, simulating ground line overhaul articulated physical environment andfocusing on simulation of distribution transformers, with the rod and stand the impact of otherfactors on detection.Secondly, this paper studies on the type and intensity of input signal detection apparatus,selects optimal and special frequency of signal as signal injection source and thecorresponding detection scheme, and applies the Fast Fourier Transform (FFT) algorithm toextract useful signal, thus effectively avoids the interference of strong induction signal. Thenthe paper makes comprehensive criteria method to determine whether there is grounddistribution wire.At last, this paper designs and develops a kind of portable intelligent detection device,and makes a series of site tests, which verify the accuracy of the state of ground wires ofdetection lines, and the test device also has a visual interface, simple operation, and easy touse.Development of this intelligent and portable detecting device, technically, can preventhuman-induced accident which is caused by transmission lines closing with ground wires, atthe same time, it brings great convenience in renovation and detection work of middle and low voltage lines, and greatly reduce the workload. Its application could strongly improve thesafety and stable operation of power grids, and possesses important economic and socialcomprehensive benefits aimed at the constructions of green power grid and har monious Southpower grid.