Abstract
In recent grid codes for wind power integration, wind turbines are required to stay connected during grid faults even when the grid voltage drops down to zero; and also to inject reactive current in proportion to the voltage drop. However, a physical fact, instability of grid-connected converters during current injection to very low (close to zero) voltage faults, has been omitted, i.e., failed to be noticed in the previous wind power studies and grid code revisions. In this paper, the instability of grid side converters of wind turbines defined as loss of synchronism (LOS), where the wind turbines lose synchronism with the grid fundamental frequency (e.g., 50 Hz) during very deep voltage sags, is explored with its theory, analyzed and a novel stability solution based on PLL frequency is proposed; and both are verified with power system simulations and by experiments on a grid-connected converter setup.
Original language | English |
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Journal | I E E E Transactions on Power Systems |
Volume | 29 |
Issue number | 4 |
Pages (from-to) | 1683-1691 |
Number of pages | 9 |
ISSN | 0885-8950 |
DOIs | |
Publication status | Published - 9 Jan 2014 |
Keywords
- Converters
- Current control
- Power system faults
- Power system stability
- Wind power generation