Modeling and simulation of time domain reflectometry signals on a real network for use in fault classification and location

Today, the classification and location of faults in electrical networks remains a topic of great interest. Faults are a major issue, mainly due to the time spent to detect, locate, and repair the cause of the fault. To reduce time and associated costs, automatic fault classification and location is gaining great interest. State-of-the-art techniques to classify and locate faults are mainly based on line-impedance measurements or the detection of the traveling wave produced by the event caused by the fault itself. In contrast, this paper describes the methodology for creating a database and a model for a complex distribution network. Both objectives are covered under the paradigm of the time-domain pulse reflectometry (TDR) principle. By using this technique, large distances can be monitored on a line with a single device. Thus, in this way a database is shared and created from the results of simulations of a real and complex distribution network modeled in the PSCADTM software, which have been validated with measurements from an experimental test setup. Experimental validations have shown that the combination of the TDR technique with the modeling of a real network (including the real injector and the network coupling filter from the prototype) provides high-quality signals that are very similar and reliable to the real ones. In this sense, it is intended firstly that this model and its corresponding data will serve as a basis for further processing by any of the existing state-of-the-art techniques. And secondly, to become a valid alternative to the already well-known Test Feeders but adapted to work groups not used to the electrical world but to the environment of pure data processing

Fault location in low-voltage distribution networks based on reflectometry - a case study

Fault location can help transport and distribution system operators in their effort of minimizing supply interruption times. Nowadays, fault location devices are widely extended in the transport grid. However, the application of these solutions to distribution networks is not a feasible option due to the high cost of this equipment. Therefore, current research is focussed on costeffective fault location techniques which are adapted to electrical distribution networks. This paper presents results of a case study, conducted with detailed simulation models of two actual low-voltage (LV) distribution grids, using PSCAD software. One is a typical rural grid with long aerial lines, while the other is a typical urban grid with shorter line lengths which are mostly installed underground. The analysis is focussed on fault location based on travelling wave theory and reflectometry methods. The simulations include distributed parameter line models and a signal injector, in order to analyse the singular effects in the waveform which are caused by the special features of the LV network. It is shown that LV networks have some unique features which are not present in medium and highvoltage grids, which makes effective fault location more challenging. Observed issues are discussed and future work is proposed in order to overcome some of them.This research was funded by the “Ministerio de Ciencia, Innovación y Universidades – Agencia Estatal de Investigación” grant number “RTC-2017-6782-3” and the European Union FEDER funds with name “LOcalización de averías, monitorización de estado y Control en redes de bAja TEnsión—LOCATE”

A comparative between IEEE and EN in the transformer derating when supplying nonsinusoidal load current. A practical case

Nowadays, power quality is a challenge for the distribution companies since the new energy policies are directed to a distributed generation system with power electronic based technologies. The reduction of distribution transformers capability when supplying nonsinusoidal load currents has a major impact within capacity reduction in distribution networks produced by technical losses. IEEE Std C57.110-2018, EN- 50464-3 and EN-50541-2 define procedures to derate transformers when supplying nonsinusoidal load currents. The aim of this paper is to compare these procedures through a real case distribution transformer that suffers problems due to high levels of current distortion.This research was funded by the “Ministerio de Ciencia, Innovación y Universidades – Agencia Estatal de Investigación” grant number “RTC-2017-6782-3”, the European Union FEDER funds with name “LOcalización de averías, monitorización de estado y Control en redes de bAja TEnsión—LOCATE” and the Horizon 2020 Program by the European Comision with project reference No 864579, H2020-LC-SC3-2019-ES-SCC