Sami Repo

Customer Classification and Load Profiling Method for Distribution Systems

In Finland, customer class load profiles are used extensively in distribution network calculation. State estimation systems, for example, use the load profiles to estimate the state of the network. Load profiles are also needed to predict future loads in distribution network planning. In general, customer class load profiles are obtained through sampling in load research projects. Currently, in Finland, customer classification is based on the uncertain customer information found in the customer information system. Customer information, such as customer type, heating solution, and tariff, is used to connect the customers with corresponding customer class load profiles. Now that the automatic meter-reading systems are becoming more common, customer classification and load profiling could be done according to actual consumption data. This paper proposes the use of the ISODATA algorithm for customer classification. The proposed customer classification and load profiling method also includes temperature dependency correction and outlier filtering. The method is demonstrated in this paper by studying a set of 660 hourly metered customers.

Smart grid power system control in distributed generation environment

This paper discusses the general aspects of smart grids and focuses on some distribution level smart grid features, such as interconnection of distributed generation and active distribution management, using automated meter reading (AMR) systems in network management and power quality monitoring, application of power electronics in electricity distribution, plug-in vehicles as part of smart grids, and frequency based load control as examples of interactive customer gateway.

Coordinated Voltage Control in Distribution Networks Including Several Distributed Energy Resources

Connecting distributed generation (DG) to weak distribution networks can often cause voltage rise problems. Traditionally, these voltage rise problems have been mitigated by passive methods such as reinforcing the network. This can, however, lead to high connection costs of DG. The connection costs can in many cases be lowered if active voltage control methods are used instead of the passive approach. In this paper, two coordinated voltage control algorithms suitable for usage in distribution networks including several distributed energy resources are proposed and studied. The first algorithm uses control rules to determine its control actions and the second algorithm utilizes optimization. The operation of the implemented algorithms is, at first, studied using time domain simulations. Thereafter, the network effects and costs of both algorithms are compared using statistical distribution network planning and also practical implementation issues are discussed.

A case study of a voltage rise problem due to a large amount of distributed generation on a weak distribution network

The paper is a case study about the integration of a relatively large amount of distributed generation into a weak distribution network. The main focus is on a comparison of methods to increase the integration capacity of distributed generation and on technical requirements from the distribution network companys point of view. The methods studied do not require major investments in the network. The paper considers voltage issues and the load transfer capability of a distribution network including wind power mills. The studies are based on real-life distribution network and load curve data.

Statistical Charging Load Modeling of PHEVs in Electricity Distribution Networks Using National Travel Survey Data

In this paper, statistical charging load modeling of plug-in hybrid electric vehicles (PHEVs) in electricity distribution networks is studied. Usefulness of National Travel Survey data in the modeling is investigated, and a novel modeling methodology is proposed where detailed car use habits are taken into account and statistical distributions of charging energies can be produced. Using the modeling methodology some example calculation results of a Finnish case study are presented with further analysis and sensitivity studies. The example calculations are made mostly from viewpoint of the Finnish distribution networks and their modeling traditions but the method can be applied internationally when relevant travel survey data is available. Example calculations are analyzed in order to assess reasonability and practical usability of the models. The models produced by the methodology can easily be used in network calculation tools commonly used by distribution network operators.

Use case analysis of real-time low voltage network management

Real-time low voltage network management is becoming possible thanks to massive smart meter rollouts, integration of them to distribution network management systems and utilization of distributed energy resources in distribution network management. Nowadays low voltage network management is emerging by integrating automatic meter infrastructure to centralized systems like SCADA/DMS. European project INTEGRIS is proposing a distributed approach based on hybrid and meshed communication. The paper is focused on low voltage network management use cases developed within the context of INTEGRIS and their ICT requirements to test the level of performance provided by the ICT architecture developed in the mentioned project.

Active distribution network — Demonstration project ADINE

Since Distributed Generation (DG) often involves renewable energy, it is important to facilitate integration of DG into existing networks. This is the aim of the EU FP6 demonstration project ADINE. It is based on the Active Network Management (ANM) concept, where automation, ICT and power electronics are used to integrate more DG by exploiting active resources instead of just reinforcing the network. The resources are mobilized through ancillary services or requirements. Five enabling solutions within ANM are pushed forward in the project: Protection relay and fault location applications, coordinated protection planning, voltage control with microturbine, centralized voltage control with SCADA/DMS and a new STATCOM. All these are demonstrated in real-life. Finally the performance of each technical solution during conditions with large amounts of DG are analyzed using a real-time simulation environment with RTDS/dSPACE. Introducing appropriate parts of the ANM concept will permit connection of more DG in distribution networks.

RTDS verification of a coordinated voltage control implementation for distribution networks with distributed generation

In weak distribution networks the amount of distributed generation (DG) is usually limited by the voltage rise effect. The voltage rise can be mitigated using passive methods such as increasing the conductor size which can, however, be quite expensive. Also active voltage control methods can be used to reduce the maximum voltage in the network. In many cases active voltage control can increase the capacity of connectable DG substantially which can lead to significantly lower connection costs. In this paper, operation of an active voltage control algorithm is viewed. The algorithm controls the substation voltage and DG reactive power and determines its control actions based on the state of the whole network. The algorithm is implemented as a Matlab program and communication between Matlab and SCADA is realized using OPC Data Access. Correct operation of the algorithm is verified using Real Time Digital Simulator (RTDS). The same algorithm could also be implemented as a part of the distribution management system (DMS).

Testing low voltage network state estimation in RTDS environment

The low voltage network operating environment is going through changes. The simultaneous introduction of intermittent renewable energy production and customer requirements for increased power quality and supply reliability are forcing utilities to rethink the role of low voltage networks. With recent advances in smart grid technology, low voltage network automation is emerging as a viable option to traditional network investments. Congestion management and demand response, for example, can be used to keep the network currents and voltages within acceptable limits. In order to control the network, we must first have a comprehensive view on the state of the network. In this paper, the low voltage network monitoring concept proposed by the FP7 European project INTEGRIS is tested. Real-Time Digital Simulator (RTDS) is used to test how well the measurements from secondary substations and smart meters can be combined in a state estimator to get a real-time view of the network state.

Real-Time Low Voltage Network Monitoring—ICT Architecture and Field Test Experience

Traditionally, distribution network monitoring has been focused on primary substations (i.e., high voltage/medium voltage level), whereas low voltage (LV) network has not been monitored at all. With rapid growth and penetration of distributed energy resources in LV grids, there is growing interest in extending the real-time monitoring to LV level. The framework program FP7 European Project INTEGRIS proposes an integrated real-time LV network monitoring solution and implements it in a cost-efficient way. This solution integrates smart metering data with secondary substation measurements to get a more accurate and real-time view about LV grid, uses “decentralized” distribution management architecture to optimize data flow, and uses International Electrotechnical Commission 61850 Standard-based interfaces to improve interoperability. This paper focuses on information and communications technology perspective, explains the implementation details of this monitoring solution, and presents its functionality/performance testing results from two distribution system operator field trials and from real-time digital simulator laboratory.