•The aim of earthing the faulted phase on the substation busbar is to establish a fault current path through FPS.•Without fault current path control the arc restrikes without interruption as long as ...the fault location is energised.•The proposed method provides sufficient time for a safe fault location and elimination without supply interruption.•Live measurements in case of arcing fault in real operating distribution systems are presented.•Special equipment was developed for arc testing purposes in resonant earthed systems.
This paper shows that appropriate manipulation of the Faulted Phase earthing Switch within the system using resonant earthed neutral, can be used to establish a controlled path for the fault current. In this way the arc extinguishes and the fault can be safely located without interruptions to the energy supply. The proposed current path control method is confirmed with simulations and extensive field-testing.
Fault location methods are crucial for reducing fault restoration time, and thus improving a network’s system average interruption duration index (SAIDI) and customer outage cost. Resonant-earthed ...systems pose problems for traditional fault location methods, leading to poor accuracy and a need for additional complexity. In this context, methods that detect fault direction (fault-passage indicators, FPI) at multiple points in the network may show advantages over a central distance-estimation method using fault locators (FL) of poor accuracy. This paper includes a comparative study of these two major fault location methods, comparing the reliability benefit from a varied number of FPIs or a central method. The optimal placement of the fault locating devices is found by formulating a mixed-integer linear programming (MILP) optimization approach that minimizes both outage and investment costs and assesses SAIDI. This approach has been tested on an example distribution system. However, to justify the universality of the algorithm, the RBTS reliability test system has also been analysed. The comparison of location methods and placement method of FPIs are useful for reliability centred planning of resonant-earthed distribution systems where fault location is to be used. Results show that a small number of FPIs that give accurate identification of direction may give more cost effective increase in reliability than a distance estimate by FL with typical levels of inaccuracy.
Studies on modeling and simulation of arc help to choose arc-extinction methods and line-selection methods in distribution network. Four kinds of arc mathematical equations are given such as Cassie, ...Mayr, Schwarz and the cybernetic model. Mayr, Schwarz and the cybernetic model are suitable for describing the arc characteristics when the grounding current is small. The arc model of Schwarz and the cybernetics is established, and these two models are compared using a test circuit of arc characteristics. The cybernetic model can set arc length, reflect the arc fault conditions and apply to simulation of single-phase arc grounding fault in resonant earthed system. The resonance earthed system model and the cybernetic model are established by ATP-EMTP, and the effect of arc length on arc impedance, steady and transient arc characteristics is analyzed. The results show that the cybernetic model is more intuitive and accurate to simulate arc grounding fault in resonant earthed system.
On the premise of improving the traditional line detection method based on transient zero sequence current (TZSC) waveform comparison, a fault line detection method based on variational mode ...decomposition (VMD) and phase space reconstruction was proposed in this paper. First, the first modal component was extracted by VMD of the TZSC of each line running up to the first feature extraction and noise elimination. Then the phase space reconstruction of the extracted modal component was carried out by using coordinate delay method. The C-C algorithm was used to estimate the optimal phase space reconstruction dimension and time delay. The mean dimension and time delay were taken respectively for creating similar phase spaces to achieve the second feature extraction. Finally, the phase space similarity matrix was established by comparing the similarity degree of every two zero sequence current phase spaces. Calculate the comprehensive correlation coefficient, and the line with the minimum comprehensive correlation coefficient was selected as the fault line. The simulation results verified the applicability of the line selection method, high sensitivity and strong anti noise.
