To solve the configuration issue when using International Electrotechnical Commission (IEC) 61850 for distributed intelligence in Distribution Automation Systems (DAS), this paper proposes the configuration solution in terms of semantic models and processing methods. Firstly, the special requirements of the DAS configuration are analyzed, consisting of the system boundary of a configuration project, the topology configuration for distributed applications, and the automatic identification of the Intelligent Electronic Devices (IED). The new models of Process, Line, and other elements are then presented based on the System Configuration Language (SCL) to describe the distribution network topology. The planned contents are allocated into a new format of the Configured IED Description (CID) file to realize the distributed applications. A register service is designed, which fulfills the automatic identification of IEDs when they are remotely placed into a DAS. The service checks the configuration status in real-time and automates the whole configuration engineering process. The case study shows that the proposed solution allows an IED to detect the real-time topology and re-establish the data flow configuration with peer IEDs independently from the master station; thus the distributed applications can be performed more autonomously and efficiently.

IEC 61850 was originally conceived as a communication standard within a substation, but is being extended to cover other areas of the power system such as distribution automation (DA). IEC TC57 Working Group 17 has set up a task force to study the information exchange required for automating the distribution network. A draft technical report IEC 61850‐90‐6 is available, which presents different use cases of DA, produces the information models and proposes the configuration method. This paper presents one of the use cases which applies distributed control on an open‐loop distribution feeder. The system consists of a number of smart terminal units (STUs) to monitor and control substation circuit breakers, sectionalizing switches and tie switches within the feeder. The STUs work together in a distributed manner to achieve fault location, isolation and service restoration (FLISR) of the feeder. The data model for this use case is presented. New logical nodes are introduced. Standardizing the data model allows interoperability between vendors, makes integration of new devices easier, and forms the basis of a smart distribution network. Another important aspect is the configuration of the system. The configuration process of a new DA system is introduced in this paper.

To address the challenge of accurately identifying tree-related high-impedance earth faults (THIEFs), a method based on long-term fluctuations in zero-sequence current is proposed. The analysis of the recorded data from staged tests in a real test network reveals the development patterns of THIEFs and their zero-sequence characteristics during the fault process. It was found that, over an extended duration, the fluctuation characteristics of the zero-sequence current RMS value curves for THIEFs differ significantly from those of the other types of high-impedance earth faults (HIEFs). By applying approximate arc length parameterization, the RMS value curve is standardized. The curvature standard deviation, the average curvature variation rate, and its standard deviation are used as feature parameters. An identification method based on an improved grey wolf optimization probabilistic neural network is constructed. Validation with staged test results demonstrates that the proposed method achieves a success rate of 97.5%, accurately distinguishing THIEFs from other types of HIEF.

The existing low voltage (LV) earth fault detection techniques using residual current measurements cannot be effectively applied to the multi-earthed TN-C system. When an earth fault occurs on the multi-earthed TN-C system, the fault current passes through the combined protective and neutral (PEN) conductor back to the source, resulting in a low residual current. However, unbalanced load switching also generates residual current through the same path back to the source, thus making fault discrimination very difficult. To address this problem, the four-wire multi-earthed TN-C system was analyzed by decoupling the mode 0 and the mode N of the equivalent circuit so that the current characteristics can be clearly studied. A new earth fault detection method is developed which compares the residual current deviation with the PEN conductor current deviation. The scheme uses amplitude ratio and phase angle difference between these two measurements to discriminate between earth faults and unbalanced load switching. The feasibility of the proposed method was verified by digital simulation and by physical tests in an actual LV distribution network. Compared to approaches based only on residual current, the proposed method demonstrates better sensitivity and reliability.