Earth Fault Distance Estimation Using Active Traveling Waves in Energized-Compensated MV Networks

Abstract

In Nordic Countries, distribution networks are traditionally unearthed and increasingly compensated. For such networks, switching their neutral point to the earth is practically applied through a resistor for better selectivity functions of earth faults. In this paper, the neutral switching and consequently an arrival time of the aerial mode traveling wave reflected from the fault point are utilized to accurately determine the earth fault distance. A concept to create traveling waves is implemented by earthing the neutral via a controlled-thyristor that provides a short period of high fault current and produces traveling waves to estimate the fault distance. Much higher transient signals are generated by earthing through an opposite charged capacitor. A capacitor-resistor divider is utilized to measure the reflected surge over a heterogeneous distribution feeder. An adaptive setting is proposed for stamping the arrival surge. The results provide evidence of the efficacy of the proposed fault distance estimation. Index Terms-Unearthed and compensated MV networks, earth faults, fault distance estimation, traveling waves. 0885-8977 (c)

Earth fault location determination independent of fault impedance for distribution networks

“…The need for high sampling frequency devices and the presence of laterals and load taps are common disadvantages of such methods. [7][8][9] Wavelet decomposition of the voltage transients associated with the fault-originated travelling waves was proposed. 10,11 Artificial intelligent tools such as ANNs or Fuzzy Logic were used.…”

“…Travelling wave techniques depend on injecting a certain wave to travel between the sending point and the fault point or by analyzing the generated transients during the fault. The need for high sampling frequency devices and the presence of laterals and load taps are common disadvantages of such methods . Wavelet decomposition of the voltage transients associated with the fault‐originated travelling waves was proposed .…”

A single-phase earth fault location scheme for distribution feeder on the basis of the difference of zero mode traveling waves

“…16 However, C-type traveling wave scheme, ie, the single-ended injecting method, in which the fault distance is calculated by the time delay between the injected signal and the reflected signal from the fault point via injecting high voltage pulse into the head end of line, is feasible in distribution network in theory. 17,18 For a distribution network whose structure is complicated, the signal detected at the head end is a superposition of multiple refracted waves and reflected waves, 19 such as from the fault point, the branch point, and the end of branch, so it is difficult to recognize the reflected wave from the fault point only by the waveform got via injecting pulse into fault phase. The following 2 ways are usually used to extract the reflection information of the fault point.…”

“…For a distribution network whose structure is complicated, the signal detected at the head end is a superposition of multiple refracted waves and reflected waves, such as from the fault point, the branch point, and the end of branch, so it is difficult to recognize the reflected wave from the fault point only by the waveform got via injecting pulse into fault phase. The following 2 ways are usually used to extract the reflection information of the fault point.…”

Earth Fault Location Using Negative Sequence Currents

“…Travelling-wave based methods [9][10][11][12][13] work based on the transient voltages and currents (impulses) which are generated at the fault location. These waves propagate away from the fault point in both directions towards the ends.…”