New Active Detection DC Distribution Network Fault Identification and Ranging Technology

With the rapid development of new energy power generation technology, the power system's requirements for power supply capacity and transmission efficiency have increased significantly. Facing the continuous development of power electronic technology, a large number of power electronic switching components and dynamic components have been incorporated into the power system. In contrast, DC distribution network has technical advantages over AC distribution network in many fields. As an important part of the DC distribution network, converter has strong nonlinear dynamic characteristics, which will have a serious impact on stable operation. In addition, the fault transient characteristics of power electronic systems are complex and short in duration, which not only limits the application of passive detection and protection technology, but also brings difficulties to the detection and location of faults in distribution lines. Traditional fault classification and ranging methods have a series of problems such as fault resistance, line branch reflection, single judgment of fault interval, and inaccurate fault location. In response to this, this article proposes a converter-based new active detection DC distribution network fault identification and ranging technology. In more detail, this technology uses converter as an active detection method for power electronics DC power supply. First, DC detection signal is injected into the line through the power electronics DC power supply. Then, the fault type signal is identified by detecting the response signal. Finally, the voltage and current spectra obtained by Fourier decomposition are used to calculate the harmonic impedance and perform fault location. This method uses the converter in the DC distribution network, which not only does not require additional equipment, but also is basically not affected by the fault resistance, with the advantages of accurate detection results and fast speed. Moreover, the experimental platform is built to conduct experiments in various failure scenarios to verify the feasibility of the technology.