In South Korea, the stand-alone microgrid on an island has synchronous diesel generators and multiple distributed generations (DGs) based on renewable energy and energy storage devices. According to the active policy of government to develop eco-friendly microgrids with zero carbon emission, many diesel generators in stand-alone microgrids are being replaced by the DGs. It brings challenges on the operation and control of multiple DGs because this causes the lack of inertia, which is originally provided from the diesel generators. This paper proposes a new decoupled frequency and voltage controller for DGs, which is able to keep the grid frequency and voltage magnitude constant. For frequency control, a frequency recovery control loop is newly added to conventional droop and inertia control loops for both the effective power sharing and stabilization of frequency response after a disturbance. For voltage control, the proposed controller regulates the grid voltage in an inertia-free mode, in which all diesel generators are disconnected, while providing the conventional reactive power-voltage droop control under a normal condition. As the result, the proposed controller can enhance the resilience and increase the penetration of renewable energies to the stand-alone microgrid. To verify the effectiveness of proposed controller, several case studies are carried out by using the practical data of a real stand-alone microgrid in South Korea.
|Title of host publication||2018 IEEE/IAS 54th Industrial and Commercial Power Systems Technical Conference, I and CPS 2018|
|Publisher||Institute of Electrical and Electronics Engineers Inc.|
|Number of pages||8|
|Publication status||Published - 2018 May 30|
|Event||54th IEEE/IAS Industrial and Commercial Power Systems Technical Conference, I and CPS 2018 - Niagara Falls, Canada|
Duration: 2018 May 7 → 2018 May 10
|Name||Conference Record - Industrial and Commercial Power Systems Technical Conference|
|Other||54th IEEE/IAS Industrial and Commercial Power Systems Technical Conference, I and CPS 2018|
|Period||18/5/7 → 18/5/10|
Bibliographical noteFunding Information:
ACKNOWLEDGEMENTS This work was supported in part by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MEST) (No. 2016R1E1A1A-02920095) and in part by the Power Generation & Electricity Delivery Core Technology Program of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) granted financial resource from the Ministry of Trade, Industry & Energy, Republic of Korea (No. 20171220100330).
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