More intelligence in the distribution network
Integration of secondary substations into a smart grid
Integration of secondary substations into a smart grid
In the past, distribution networks were planned according to the "top-down" clear direction of energy flow, from high voltage, through medium voltage to low voltage at the end customer. The sizes of operating equipment such as transformers, cables and safeguards were designed based on the dwellings to be supplied, typical load profiles, statistical utilisation factor and a sufficiently large safety factor.
Over the last few years, the classic planning model and the technology for supplying electrical energy have changed due to many external influences. Therefore, the requirements for efficient networks play as great a role as the increasing amount of power supplied by renewable energies. These influences mainly apply to the low voltage network. Critical operating conditions and overloads can occur here because networks that were planned in a classic way were not designed for these.
Secondary substations are increasingly becoming intelligent crosspoints: They take on tasks from simple reading, fault location, interference detection and power quality analysis to complete remote control or even automation. The following requirements must be allowed for, in particular when retrofitting existing secondary substations
- Limited space: Additional monitoring and telecontrol systems must be adjusted to the limited expansion potential of secondary substations.
- Cost-effectiveness: On the one hand, the components must be very easy to install as "plug-and-play" components but, on the other hand, they must cause as few costs as possible in continuous operation.
- Scalability: The solutions should provide a cost-effective introduction and be easy to extend according to requirements and the desired selectivity.
Distribution networks are the bottleneck of the energy transition
Conversion of the electricity network
98% of all renewable energies are fed into regional and local distribution networks. It is therefore becoming apparent that the development of distribution networks cannot keep pace with the increasing amount of renewable energies in the energy mix.
An indicator for this is the increasing number of cut-off interventions in the distribution networks, i.e. cutting off the renewable energy systems. According to the German Federal Government, each 300th renewable kWh that is generated is cut off. This means that distribution network operators must invest in modern, smart networks.
In its distribution network study, the German Energy Agency (dena) calculated a fi gure of 27.5 billion euros for required development and modifi cation tasks by 2020. However, new studies prove that intelligent technology can almost halve these costs.
Consequences for the energy industry:
The conversion of the electricity network has profound consequences for the energy industry:
- Load fl ow reversal culminating in re-feeding
- Operating equipment overloads
- Voltage range increases at the supply point
- Increasing energy over-production
- Imbalances, mainly in the low voltage network
- Increased demand for storage media
- Infrastructure measures for electrical mobility
Janitza solutions for distribution network operators
Janitza provides comprehensive solutions, from the universal meter to class A power quality analysers. Compatible components (cable split core current transformer to visualisation) ensure functional safety. The modular system approach enables the user to choose the desired individual components (cable split core current transformer for retrofit, measuring device, modem, power quality analysis software, reporting tools, etc.).
In addition to the enormous time saving for engineering, this mainly saves costs at all levels. The open communication structure ensures that all data that is recorded can be integrated into existing systems easily. As the information is stored in a central database, mobile evaluation of the network status via smartphones, tablets or PCs is also possible, in addition to easy diagnosis on the master display in the control room.
The number of network elements to be managed (feeder, store or electrical mobility) continues to increase; the amount of data therefore also increases. An intelligent evaluation provides a valid basis for decisions and therefore makes this information overload manageable. Maintenance strategies can therefore be adjusted or planning processes can be optimised, which in turn ensures that the distribution networks are stable and safe. In addition, the power quality can be evaluated quickly in accordance with EN 50160 and documented in lawful manner.
Our system components in detail:
- Comprehensive range of measurement devices, from the simple power measuring device to the class A power quality analyser
- GridVis® network visualisation software
- Database management
- Alarm management
- Reporting tools, e.g. EN 50160 annual report
- Communication devices (gateway, modem, etc.)
- Wide range of current transformers Commissioning and training
- Complete transparency from high voltage to low voltage
- Safe, self-sufficient operational management at low-voltage level
- Automated network status identification for each node
- Optimal utilisation of the existing infrastructure
- Low voltage level becomes smart
- System solutions that can be extended modularly
- Multifunctional connection to the control centre
- Minimise interruption times and downtimes
- Lower investment costs using intelligence rather than copper