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To further improve the performance of distance protection in renewable energy systems, a distance protection method is proposed, which considers the effects of control system and the distributed capacitance effect of the line. When an asymmetric fault occurs in the system, combined with the control characteristics of the converter, the sequence impedance characteristics of the grid and the pure resistive feature of the fault resistance, three unknowns in the fault loop equation can be eliminated, and the solution of the fault distance can be solved in the R-L model. Then, the setting point is set based on the calculation results in the R-L model, and the real electrical quantity at the setting point can be deduced by the calculation formula in Bergeron model. Finally, the equation from the setting point to the fault point is simultaneously solved to reduce the distributed capacitance effect on the distance protection. The simulation results testify that the method is less influenced by the fault features of the converter and fault resistance. It still has good performance in long line.

Single phase line‐broken (SPLB) fault is one kind of high impedance fault (HIF). When a SPLB fault occurs, there are four scenarios: SPLB fault with neither side conductors grounded (SPLB‐NSCG), with source side conductor grounded only (SPLB‐SSCG), with load side conductor grounded only (SPLB‐LSCG), with both side conductors grounded (SPLB‐BSCG). Traditional HIF detection methods using current or voltage characteristics have low sensitivity to SPLB fault. In this paper, voltage characteristics are analysed firstly in the cases of the first three scenarios of SPLB fault, respectively. Theoretical analysis finds that the voltage at both the sides of the disconnection point is significantly different. A high sensitive SPLB fault detection method based on differential voltage is proposed for radial distribution network with different data synchronization ability. Finally, SPLB fault location methods based on centralized intelligent mode feeder automation (FA) and intelligent distributed mode FA are proposed. Simulations based on PSCAD verify that the proposed SPLB fault detection method is feasible, highly sensitive and immune to the neutral grounded mode, fault scenarios and fault resistance. [ABSTRACT FROM AUTHOR]

Feeder automation is important to improve the reliability of power supply for distribution network. Existing voltage‐time feeder automation scheme exists the problems of long fault processing time and the upstream switches of the fault point need to tolerate fault current twice and the upstream sections need to experience two short time power outage. In this paper, a quick fault location and isolation method for distribution network based on adaptive reclosing is proposed. Three key technologies of the strategy are introduced, including a phase segregated switch of the distribution network based on the permanent magnet operating structure, the phase selector based on transient current characteristics, and the temporary fault and permanent fault identification method based on the power frequency voltage characteristics. The proposed strategy can avoid the second impact on upstream switches and power‐off of the upstream section in case of the permanent fault and can effectively shorten the fault processing time. [ABSTRACT FROM AUTHOR]

The authors proposed a faulty feeder detection method based on the combination of feature extraction and information entropy in the distribution network. Firstly, analysed the characteristics of a transient zero‐sequence current (TZSC) waveform, and constructed a mixed atom dictionary by a cosine packet and a wavelet, and then, the authors adopted the matching pursuit algorithm to extract characteristic atoms of each feeder. For energy aspects, used energy spectrum entropy (ESE) to measure; for the waveform similarity, calculated correlation coefficient between characteristic atoms and the original TZSC, then, the authors obtained the ESE of modified atoms and integrated atoms, respectively. In a faulty feeder detection criterion, calculated the difference value between the maximum and the minimum of integrated atoms ESE, and compared the value and the threshold. If the value is smaller than the threshold, the bus is judged as a faulty feeder, otherwise, the maximum corresponding to the feeder is judged as the faulty feeder. Simulation and field tests show that the method can accurately judge the faulty feeder, and its accuracy is immune to transition resistance, iteration numbers, data window length, different compensation degrees, capacitor switching, and unbalanced load. [ABSTRACT FROM AUTHOR]