Distribution system reactive power management under defined power transfer standards

In light of high levels of distributed generation on distribution networks, voltage and reactive power management is challenging operators of both the distribution and transmission systems. The European network codes being developed by ENTSO-E are likely to call for “power transfer standards” to be defined, specifying the voltage and power factor bands which must be maintained at the transmission / distribution interface. This paper deals with how the DSO may meet such a power transfer standard as defined for nodes where there is significant wind generation connected on the distribution system. The work addresses the identification of the existing active and reactive power capability which could be achieved and a methodology for sizing and siting any distributed compensation required to deliver the desired characteristic in a manner which best meets utility priorities. The proposed methodology is tested on a network and the results discussed. Finally the characterisation method proposed is used to assess a number of alterative options which may reduce the requirement for compensation to be installed.