Low-voltage Ride-through Response of Renewable-Penetrated Distribution Networks

Abstract

Low voltage ride-through (LVRT) is a grid code that enables distributed energy resources (DERs) to stay connected under voltage sags. However, a DER is exposed to being tripped if it does not meet the LVRT requirement. For a renewable-penetrated distribution network (RPDN), the lost amount of DER capacity over a voltage sag is the so-called LVRT response of an RPDN. Besides the behavior of DERs during the transient undervoltage condition, their trip may have a negative impact on transmission system security. This paper addresses a general mathematical model for analyzing the DERs' behavior during the transient condition. The proposed model is implemented to obtain the RPDN's LVRT response to different voltage sags. This LVRT response is defined as such that concerns the uncertainty in the output power of renewable resources. Furthermore, the expected ride-through capability index is introduced to capture the generation availability due to meeting the LVRT requirements. The studied RPDN shows the lowest capability is for voltage sags with depth and duration greater than 0.70 pu and 0.4 sec, respectively. Also, with 40% and 20% reductions in solar and wind generation compared to their nominal values, the maximum LVRT response of the RPDN decreases from 2420 kW to 1852 kW. Also, the ERC of 66% is achieved for the RPDN, stating the expected loss of 34% of the total DER generation.