Frequency Response Impact of Integration of HVDC Into a Low-Inertia AC Power Grid

The integration of a high-voltage, direct current (HVDC) transmission interconnection could have a significant impact over the frequency control of the power grid to which it is connected, especially when the system inertia is low. The contribution of this work is to develop a framework to examine such an impact with a consideration given to the system inertia and to use a full dynamics model to studythe system frequency response. Using Southern Cross Transmission (SCT) DC Tie at Electric Reliability Council of Texas (ERCOT) as an example, this paper quantifiesthechanges to responsive reserve (RRS) requirement and the risk of the frequency overshoot resulting from the loss of HVDC tie.