Testing of Decentralized Distribution Automation System - Use Case Coordinated Voltage Control

The control and monitoring of the distribution network is going to go through some profound changes in the future, while the amount of distributed energy production, automation and controllable resources increase in the network. In such situation the assumption of unidirectional flow of energy from the production through transmission network and distribution network to customers might not be valid any more. Distributed energy resources, such as wind turbines and photovoltaic plants are often located near the consumption and connected to the distribution network instead of transmission network. With the use of novel network management tools and coordinated voltage control an acceptable state of the network can be maintained and the whole potential of the system utilized. This thesis presents a new distribution automation concept developed in IDE4L project as well as the construction of the test environment and test results. The automation system of the IDE4L project is based on a decentralized, modular and hierarchical approach that aims to reduce the rigidity of a traditional control center based system while providing a large variety of features for network monitoring and control. The main parts of this system are substation automation units (SAU), that spread out the decision making and control of the network. Each SAU acts as an individual control unit that controls and monitors devices in that part of the network and delivers only necessary data to the higher level control center. The aim of this thesis is to investigate and list especially non-functional requirements to be tested on a decentralized automation system. The main focus of testing is at the operation of the automation architecture and its non-functional requirements. The testing is conducted at the Real time digital simulator laboratory with actual intelligent electronic devices (IED) and SAU. Reliability and availability for the whole system and its components is studied with a theoretical approach. All other tests, such as failure and error handling, time performance and resource utilisation, are carried out with the laboratory set up. Testing did not bring up any major issues or constraints that would occur when the system size is scaled up, but some observations were made about the test set up as well as commissioning and interoperability of IEDs that should be considered