Competitive cross-voltage level procurement of reactive power considering reliable capacity from wind and photovoltaics

摘要

Transition toward high shares of power production from wind and photovoltaics(PV) brings about a substantial increase in controllable reactive power (Q). Thecapability to provide Q independent of active power production (24/7) is availableat comparably low or even zero investment cost. Yet, this capability is not requiredby network connection codes and only rarely utilized, even if available. In a firststep, we take an overall economic perspective and review the economic competitionof 24/7 Q provision from variable renewable power plants (VRPP) with alternativeQ resources. Technical restrictions to be respected are discussed, as well asthe reliability requirements related to investment-planning relevant Q provision.Competitiveness is significantly influenced by Q utilization rate and connectingvoltage level. For practical implementation of 24/7 Q procurement from VRPP, itsvalue needs to be assessed. We review possible approaches from overall economicperspective. We conclude that in operational decisions, VRPP Q should be valuedat marginal cost, whereas in Q investment planning decisions, full cost should beconsidered. We derive the pros and cons of making 24/7 Q provision a mandatorypart of network connection codes. For system operators (Sos) to integrate availablecapacity, regulatory acknowledgment of related revenue impact should be considered.We present possible solutions. Summarizing, the contribution presents thestatus quo in research on cross-voltage level, investment-relevant Q provision byVRPP. Using the presented methodology for value assessment, areas for furtherresearch are systematically pointed out.