The advent and deployment of significant levels of photovoltaic and wind energy generation in the spatially dispersed mode (i.e. residential and intermediate load centres) may have deleterious effects upon existing protective relay equipment and its time-current co-ordination on radial distribution circuits to which power conditioning equipment may be connected for power sell-back purposes. Note that significant in this context is now generally agreed to mean greater than 50% of a feeder's minimum load capacity rating.