Modelling the NPCC System with 12.5% Wind Penetration Christopher Matthews Undergraduate Researcher Summer REU July 22, 2015 Knoxville, TN

What is a Balancing Authority? Traditional AGC Corrects deviations from scheduled system frequency and scheduled tie line exchanges Each area has a balancing authority What is a Balancing Authority?

Area Control Error 𝐴𝐶𝐸= ∆𝑃 𝑇𝑖𝑒 +𝐵∆𝑓 Damping factor is negligible 𝐵= 1 𝑅 +𝐷 𝑅= ∆𝑓 ∆ 𝑃 𝐺𝑒𝑛 Damping factor is negligible ACE should cross zero at least once every 10 minutes MISO Energy ACE Graph 𝑃 𝑇𝑖𝑒 : Tie-line power 𝑓: System Frequency 𝐵: Frequency bias factor 𝑅: Speed regulation factor 𝐷: Damping factor 𝑃 𝐺𝑒𝑛 : Generated power

Doubly-Fed Induction Wind Generator Most common type of wind generator Asynchronous generation Requires more control than traditional generators Added controls adjust power output to maximum

Inertial Response Comes from kinetic energy in rotating masses First few seconds of response Determines magnitude of frequency excursions Hidden in variable speed wind turbines

User Defined Models using DSATools UDM Regulating Unit DFIG

Verifying Models Show correct frequency regulation Tie line flow returns to scheduled with frequency

Illustrate effect of losing system inertia

AGC Response with Variable Wind

Future Work Immediate Response Emulated inertia Droop control Long Term Deloading control Pitch control Rotational speed control

Acknowledgements This work was supported primarily by the ERC Program of the National Science Foundation and DOE under NSF Award Number EEC-1041877. Other US government and industrial sponsors of CURENT research are also gratefully acknowledged.

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