IEEE Transactions on Applied Superconductivity, 2016
For a high penetration micro-grid, improving its low-voltage ride-through (LVRT) capability under some minor or temporary faults can contribute to reinforcing power support and reducing network instability. In this paper, the comparison of a superconducting fault current limiter (SFCL) and a dynamic voltage restorer (DVR) for LVRT capability enhancement of a 10 kV micro-grid is conducted. Concerning the micro-grid which includes distributed photovoltaic (PV) generation, energy storage and loads, the effects of the SFCL and the DVR are compared in detail, and related theoretical analysis, simulation study, and economical evaluation are carried out. From the demonstrated results, the suggested two devices can both assist the micro-grid to achieve the LVRT operation, but the economics of the DVR are weaker than the SFCL. Moreover, compared to the DVR, the SFCL enables the energy storage unit to offer better control effects in power stabilization. From technical and economic perspectives, the SFCL is a more preferable choice than the DVR.
- Dynamic voltage restorer (DVR)
- Low-voltage ride-through (LVRT)
- Superconducting fault current limiter (SFCL)
Fig. 1. Configuration structure of the flux-coupling type SFCL.
EXPECTED SIMULATION RESULTS:
Fig 2. Three-phase PCC voltages under the short-circuit fault. (a) Without auxiliary, (b) with the SFCL and (c) with the DVR.
Fig. 3. Operation characteristics of the micro-grid under the short-circuit fault. (a) PCC current and (b) frequency fluctuation.
Fig. 4. Power characteristics of the micro-grid under the short-circuit fault. (a) Exchange power Pex, (b) DG total power PDG-total and (c) load power PLoad.
Fig. 5. Operation characteristics of the three DG units under the short-circuit fault. (a) DG1, (b) DG 2 and (c) DG3.
Based on the theoretical analysis, simulation study, and economic evaluation, this paper carries out the comparison of the SFCL and the DVR for enhancing the micro-grid’s LVRT capability, and the following conclusions can be obtained. 1) The SFCL and the DVR can both assist the micro-grid to meet the LVRT requirements. 2) Regardless of the full-compensation or non-full-compensation DVR, its total cost is more than the SFCL. Although the full-compensation DVR is able to offer better transient performance indexes, there may be a tradeoff between performance contribution and device cost. 3) Applying the SFCL enables the energy storage unit to offer better control effects in power stabilization. From technical and economic perspectives, the SFCL will be a more preferable choice than the DVR. In the near future, the detailed optimization design and experimental test of the SFCL will be conducted, and the results will be reported later.
- Baoquan Liu, Fang Zhuo, Yixin Zhu, and Hao Yi, “System Operation and Energy Management of a Renewable Energy-Based DC Micro-Grid for High Penetration Depth Application,” IEEE Trans. Smart Grid, vol. 6, no. 3, pp. 1147–1155, May 2015.
- Feng Zheng, et al., “Transient Performance Improvement of Microgrid by a Resistive Superconducting Fault Current Limiter,” IEEE Trans. Appl. Supercond., vol. 25, no. 3, June 2015, Art. No. 5602305.
- Zhangjie Fu, Sun Xingming, Qi Liu, et al. “Achieving efficient cloud search services: Multi-keyword ranked search over encrypted cloud data supporting parallel computing,” IEICE Trans. Commun., vol. 98, no. 1, pp. 190–200, January 2015.
- Tinghuai Ma, Jinjuan Zhou, Meili Tang, et al. “Social network and tag sources based augmenting collaborative recommender system,” IEICE Trans. Inf. Syst., vol. 98, no. 4, pp. 902–910, April 2015.
- Zhihua Xia, Xinhui Wang, Xingming Sun, et al. “A Secure and Dynamic Multi-Keyword Ranked Search Scheme over Encrypted Cloud Data,” IEEE Trans. Parallel Distr. Syst., vol. 27, no. 2, pp. 340–352, Feb. 2016