HTS cables: Dealing with the challenges of DER

The development of distributed energy resources (DER) is progressing rapidly. In modern grids small and medium-scale DER together with expanded large-scale renewables will supply a significant part of the energy demand. Nevertheless, the integration of these sources into the local grids represents a big challenge due to bottlenecks such as transport capacity, voltage fluctuations, fault levels and reactive power. When designing a distribution network with mixed load and generation, struggling to get a smooth voltage profile and limited short circuit currents is common. These issues can be solved more efficiently by using the latest generation HTS (high temperature superconducting) cables. These smart cables have an improved non-linear voltage-current characteristic that enables a smooth voltage profile during normal operation, while limiting the current during short circuits and improving the grid stability. In this way DER, as well as offshore wind farms, can efficiently and flexibly be integrated into modern and existing grids. The Dutch DSO Alliander, together with the nkt cables/Southwire joint venture Ultera, is studying all these capabilities of HTS technology to solve these issues and support the penetration of DER and large-scale renewables. An important step will be the 6 km cable Alliander is willing to install in the city of Amsterdam where the potential of smart FLC HTS cables will be demonstrated.