Overload and overvoltage in low-voltage and medium-voltage networks due to renewable energy - some illustrative case studies

This paper presents the use of curtailment to allow more wind or solar power to be connected to a distribution network when overcurrent or overvoltage set a limit. Four case studies, all based on measurements, are presented. In all cases the hosting capacity method is used to quantify the gain in produced energy for increased levels of distributed renewable energy resources. A distinction is made between "hard curtailment" where all production is disconnected when overcurrent and overvoltage limits are exceeded and "soft curtailment" where the amount of production to be disconnected is minimized. It is shown that the type of curtailment method used has a large impact on the amount of delivered energy to the grid. The paper further discusses details of the curtailment algorithm, alternatives to curtailment, the communication needs and risks associated with the use of curtailment. (C) 2014 Elsevier B.V. All rights reserved.