Case studies

EWE Uses UT Smart Apps to Connect Renewables

EWE Uses UT Smart Apps to Connect Renewables

Analyzing the Impact of Prosumers on your Network

Maintaining stability in the electrical grid: It is one of the major challenges for electrical utilities in the field of renewable energies. At times when consumption of energy is fine, we now see raises and drops in the low voltage network due to energy producing sources, e.g. wind turbines and solar panels (PV, photovoltaic) on the roofs of our houses or wind / solar parks. These so called “Prosumers” cause instabilities in our low voltages distribution networks that need to be managed properly.

AED-SICAD now provides special Apps for fast and simple network impact analysis by means of network calculations together with tools for planning and sketching of alternative solutions to solve these kinds of problems. These tools should help utilities to fulfill their legal obligations in the context of renewable energies. The Apps will help them to perform a network quality assessment for any new application to install a solar panel or equivalent device in order to improve the overall quality of the distribution network.

 

UT Smart Apps - Easy-to-Use Interface

Together with EWE Netz GmbH, Germany’s 5-th largest utility in the northern parts of the country, the Apps for such a „smartGIS“, were developed. The aim of these Apps is to support the assessment process of new Prosumer applications to provide energy into the existing distribution network. The evaluation is done by means of voltage drop calculations without any of these Renewable Energy Sources (short: “renewables”) being active, or by calculating the raise in voltage level assuming that that no one consumes energy and only the renewables produce energy. Based on Esri’s ArcGIS Server these Apps enable a process of simulation for different network planning situations. The Apps are built using a straight forward step-by-step approach. Results of any kind of assessment are presented in green-yellow-red colors to indicate further directions. In case critical values are exceeded an employee may defer the case to an expert who will perform more detailed simulation scenarios. Here you may think of switch-order simulations, cable enforcements, or perhaps even the use of smart grid technology, like exchanging the transformer with an adjustable transformer in the substation. The user interface our UT Smart Apps offers functionalities for server-based attribute editing and sketching of network planning objects in the GIS. The JavaScript/HTML5 -based Client Framework for UT Server has proven to be an elegant platform for integrating many different functional requirements.

Upfront we need to investigate the situation in a substation: How many service points and residents are being served by this station? How much energy is being fed in to the low voltage network? Is the current transformer powerful enough to supply all necessary energy? How is the entire voltage drop over the entire feeder network? The UT Smart Apps, especially the CALC App, will take all relevant GIS data through a feeder trace and transfer it on-the-fly into the network calculation software package. Results will be displayed in tabular form as well as on the map by means of stop-light colors. The User Interface is simple, straight forward and easy-to-learn; the User Experience is geared to success.

Apps supporting planning and simulation

The PLAN App allows uncomplicated network analysis on the impact of your renewables in different alternative scenarios: Am I to encounter difficulties and outages with a certain scenario? The App enables you to sketch new network elements, by means of an elegant gallery of predefined planning elements: attribute values are preset so that you as a planner do not have to enter them during the sketching. If you want to, they may of course be altered afterwards.

The CALC App will bring the newly sketched network elements together with the existing network data and perform a network calculation to determine the impact of the planned and simulated new network. The network planner might even consider different measurements e.g. the stepwise increase of transformer levels. Alternatively he might also enlarge the electrical capacity of the network by laying out an extra cable, which – of course – is a more expensive scenario! All actions are actually combinations of sketched planning elements that are “merged” with the existing network before performing the assessment calculations. Results are visualized on the map in green-yellow-red colors.

In many occasions it is a good option to switch parts of the network in such a way that the newly planned objects will be fed by another feeder in the network. The PLAN App can place such temporary switches and simulate their impact by performing a new network trace and a network calculation. Altogether the Apps bring quite complicated matters to the end user in an extremely easy way.

Separating as-built network data from the planned network

In most utilities we want to keep the as-built network data as they are. There is a daily process of updating this network data. Planning new networks will happen in a separate layer. The challenge is then, to bring as-built and planned network data together in order to perform the correct network traces and network calculations. The PLAN and CALC Apps handle this for you by temporarily applying the planned features to the existing data. The result works as if someone was editing the data and performing a trace and doing a network calculation. This process is then ended without saving the data and in this way keeping the as-built data unharmed.

The calculation results for any electrical feeder may be presented in a tabular form or in the map. It is also possible to export the entire process into a nicely formatted report for later documentation of the different planning alternatives.

Such reports are documents that are associated to the planning project. In general the planning project and its associated alternative scenarios are graphically presented on the map. This provides an overall overview to the network planner. The attached documents can be retrieved at any later point in time. Most likely a network planner will remove unnecessary planning alternatives.

As-builting Planned Network

Generally after doing your network analysis and simulations, the next phase that follows is the “as-builting”, when plans become reality. The PLAN App provides some excellent tools to support his process. There is an entire suite of construction and dimensioning tools to project the new network into and on top of the existing network. The gallery of planning materials is extended for this specific purpose, also enabling the user to pick materials from the utility companies Material Management System, most likely, containing Compatible Units (CU). The predefined attributes of these CUs are automatically set for all planning elements in the gallery of sketching tools. Attribute editing after sketching is always possible.

In this phase a network planner will have many scenarios in parallel. He may also start a new scenario based on an existing one. For each scenario the PLAN App will keep track of a detailed list of materials to be used, the so called Bill of Materials: how many meters of cable type so and so were designed and how many new devices were installed or old ones removed? Most of our utilities keep this material information in external system, e.g. SAP. The PLAN App allows reading relevant information from these systems.

The Bill of Materials is also saved as a document that is permanently associated to the planning project and the as-built scenario. Such lists may be printed, but they can also be exported to any other office system, e.g. Excel, etc

Arrival of data and requirements that apply to data?

To be able to provide the necessary network information for any kind of network calculation, your data need to fulfill a minimal set of requirements:

  • There is full network topology, including internals of stations
  • All switchable devices in the network topology have correct normal position settings
  • All Renewables must be associated to a service point or other device in the network

The built-in calculation engine performs its network calculations based on an Arc-Node-topology and a so called „Cable Book“, with important electrical properties of cables and devices being used in the calculation process.

Web Services and Apps

All these editing, planning and simulation capabilities are actually based on Web services using Esri’s ArcGIS Server technology. AED-SICAD provides additional capabilities to these Web services with the UT Server. Over the last two years the UT Server was enhanced with Editing, Planning and Calculation capabilities that reside in the new Server extensions UT Server EDIT, PLAN and CALC.

Of course the end-user needs client Apps to enable the server capabilities. This is handled by using the Esri ArcGIS Server API for JavaScript. We created the EDIT, PLAN and CALC Apps all working together with the INFO App that provides generic viewing and querying functionality on your utility network.

EWE Netz GmbH staff have been using these capabilities since June 2012 in a production environment. The results are excellent: the UT Smart Apps have helped to reduce the processing time of applications for renewable energy by customers drastically. This has led to less instability in the distribution network. In fact, EWE Netz clearly leads among European peers when it comes to grid reliability: In 2015, their customers suffered on average only 3 minutes per year electricity downtime, which compares e.g. to 68 mins in France on average.

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