PNNL

Abstract

Volt/var control (VVC) of smart PV inverter is becoming one of the most popular solutions to address the voltage challenges associated with high PV penetration. This work focuses on the slope sensitive local droop VVC recom- mended by integration standard IEEE1547, rule21 and addresses their major challenges i.e. vulnerability to instability (or voltage oscillations), significant steady state error (SSE) and appropriate parameter selection under external disturbances. This is achieved by proposing an autonomous, local and adaptive VVC which has two major features i.e. a) it is able to ensure both low SSE and control stability without compromising either and; b) it dynamically adapts its parameters to ensure good performance in a wide range of external disturbances such as sudden cloud cover, cloud intermittency, substation voltage change. Moreover, the adaptive control does not depend on the feeder topology information, thus also shown to be adaptive to the error in feeder topology information. The proposed control is implementation friendly as it fits well within the integration standard framework and depends only on local bus information. The performance is compared with the existing droop VVC methods on an unbalanced 3-phase IEEE 123 test system with detailed secondary side modeling.