System Scheduling with Pumped-Hydro Plants with Different Grid Connection Schemes

The increase in inverter-connected generation sources is causing a remarkable decline in the overall system inertial response, which shall be balanced by a significant amount of frequency response services. This represents a significant challenge against the ability to ensure secure and reliable power networks whilst implementing a cost-effective transition towards a low carbon paradigm. This paper assesses the value of providing different types of flexible ancillary services from pumped hydro plants depending on their specific grid connections implementations. The flexibility envelopes associated to each implementation are included in a security-constrained system scheduling model. Case studies consider a low carbon system scenario of the Great Britain and highlight the value of providing both inertial and frequency responses.