The use of voltage envelope and voltage dependent loads to increase the penetration of renewables

This study presents an analysis on how transformer tap control can be used to manage distributed energy resources (DERs) output and increase the grid's hosting capacity. The principle of operation behind this approach is similar to Conservation Voltage Reduction (CVR) in that both utilize the voltage dependence characteristics of loads. However, the distinction between CVR and this approach is that while CVR reduces the substation voltage to lower the load consumption with an aim of reducing the peak load, this research analyses the effect of raising the substation voltage for low load management during peak DER output to increase the grid hosting capacity or for contingency management. The voltage dependent characteristics of the load are explored to exploit the allowable voltage envelope and increase the penetration of DER. An IEEE 14 bus network is modelled in MATLAB environment using the PSAT toolbox. The load power to voltage relationship is implemented using voltage dependent loads (VDL). The substation voltage is varied by transformer tapping and the corresponding change in power consumed established. An increase in the grid's hosting capacity is determined by evaluating the power changes at the slack bus during this variation. It is observed that operating at a higher substation voltage helps to increase the power consumption of the load on feeders with VDL. This result is used to quantify the increase in the volume of DER output that can be exported to the grid.