In this project the potential for ancillary services provision by distributed energy resources is investigated. Specifically, the provision of reactive power control by combined heat and power plants is examined, and the application of the new standard for DER communication systems, IEC 61850-7- 420, is investigated as a means to improve the control possibilities. To gain first-hand experience on the topic, a demonstration case has been designed and implemented in the project. The demonstration case is based on the issue of reactive power balancing in distribution grids, an issue that is attracting increasing attention from the distribution grid operators due to three main reasons, that all call for flexible reactive power control resources: First, the presence of DER, like wind turbines and CHP plants, makes the conditions less predictable, second, the intensive transform from overhead lines to underground cables has changed the reactive power balance, and third, the TSO has introduced restrictions in the allowed exchange of reactive power between the transmission system and distribution grids (known as the Mvar-arrangement). The demonstration includes a CHP plant with an electric power rating of 7.3 MW on two synchronous generators. A closed-loop control is implemented, that remote controls the CHP plant to achieve a certain reactive power flow in a near-by substation. The solution communicates with the grid operator’s existing SCADA system to obtain measurements from the substation, and subsequently determines and transmits reactive power setpoint values to the generators in the CHP plant. An important part of the implementation is the communication link between the controller and the CHP plant, which is implemented in compliance with IEC 61850-7-420 using an industrial PC platform. In this paper, the implementation and the experience gained is described in more detail. Due to the comprehensiveness of IEC 61850-7-420, the implementation has been a challenging, but achievable task. The test results of the entire control system look promising, but also reveal some issues related to the quality of measurements, and to the response time of the CHP plant, that need further improvement.
|Title of host publication||Proceedings of the CIGRE session 2010|
|Publisher||International Council on Large Electric Systems|
|Publication status||Published - 2010|
|Event||CIGRE session - Paris, France|
Duration: 1 Jan 2010 → …
|Period||01/01/2010 → …|