Abstract
At a high penetration level of distributed PV, a portion of the conventional generation would be displaced, resulting in the loss of the main sources of dynamic reactive power in the transmission networks. Consequently, power systems may become more vulnerable to voltage instability events. This paper focuses on long-term voltage stability assessment and enhancement in power systems with a high penetration of distributed PVs. Distributed PVs, when properly controlled, can provide ancillary services that are traditionally delivered by spinning generators and voltage regulators to support the bulk power system. A case study is presented that provides dynamic reactive power reserves by distributed PV systems to support the bulk power system.