Detecting network state variables in real time
The "ENERGIE" research project led by SWK NETZE is aimed at determining the network state in the low-voltage grid in "real time" using just a few measuring points. The measuring devices and concepts required for this are being developed by the Janitza company.
In a first step, the engineers will record operating values such as the current, voltage, cos(φ), events such as power failures, under- or overvoltage and overcurrent as well as transients and power quality values at critical points in the low-voltage grid. It is not possible, however, to install measuring devices at all nodes in the low-voltage grid. Düsseldorf University of Applied Sciences is therefore developing a computational algorithm that can determine the missing data.
In addition, the results and any forecasts can be considerably refined using master, weather and status data for the equipment. The use of powerline communications technology (PLC), i.e. data transmission via electricity grids, ensures secure and reliable communication between the remote measuring points in cable distribution cabinets and local substations. Existing systems use a frequency range below 150 kHz, the so-called CENELEC band. Smart grids require, however, data rates greater than those achievable with the CENELEC band. On the other hand, it is also not possible to transmit the data over the required distances at frequencies greater than 1.6 MHz. For this reason, the ENERGIE research project is using a range between 150 and 500 kHz for the PLC. These frequencies achieve both long ranges and better bandwidths.
To keep the data to a minimum, these will already be sufficiently bundled locally to ensure that they are also kept within manageable limits with large-scale use and the associated installation of several measuring points. The ultimate goal of the research project is to enable the self-sufficient and independent evaluation of the network state of the respective areas supplied by the local network stations.
The tasks of the project partners in detail
In addition to coordinating the project, SWK NETZE will work together with the project partners to develop the framework conditions and provide the information for developing applications and computational algorithms. In addition, SWK NETZE will prepare 20 local grids so that the demonstrators can be installed immediately at the beginning of the field testing phase.
The core task of Janitza GmbH will be to produce a robust and modular network analyser for the real-time detection of network state variables. Here a local algorithm will be integrated, which reduces the data traffic and encrypts it through security mechanisms.
In collaboration with the University of Duisburg-Essen, devolo AG is developing a real-time capable PLC data transmission system with an interface to connect demonstrators for controlling the network state. Main tasks will also include analytical and experimental investigations of energy-based systems with regard to EMC considerations when deploying PLC technology and network analysers.
Düsseldorf University of Applied Sciences will be responsible for evaluating a model and developing a grid calculation method based on real measurement data. This will be used to derive the theoretical calculation methods for analysing data, calculating load flows and estimating the state in the low-voltage grid.
On behalf of SWK NETZE, the Lovion company will implement the real-time values, calculation algorithms and database systems for their depiction and analysis in the form of a real-time geographic information system (real-time GIS).
Field test planned for 2016
The project coordinators are planning field tests at the beginning of 2016. This will be the first time that the demonstrators will be deployed with their full range of functions in the low-voltage grid. The field test will be completed during the last three months of the project with a fully implemented system check using the test catalogue. Finally, a cost-benefit analysis is envisaged to conclude the project.
09/2014 – 08/2016
SWK Netze GmbH
St. Töniser Str. 124
47804 Krefeld, Germany