Farmland and primary farmland protection are important contents of land management and land use planning of China. In the new round of land use planning and database construction, primary farmland protection zones are...Farmland and primary farmland protection are important contents of land management and land use planning of China. In the new round of land use planning and database construction, primary farmland protection zones are required to have high integrity and connectivity. Using landscape pattern indexes, the integrity and connectivity of primary farmland protection zones was studied in Licheng District of Jinan City. The results showed that, except patch area standard deviation, the other indexes including average patch area, patch area variation coefficient, patch edge density, largest patch index, and mean euclidean nearest-neighbor, all indicate high connectivity of primary farmland protection zones after layout adjustment. A simple and convenient method for identifying the integrity and connectivity of primary farmland protection zones was supplied.展开更多
Fast and reliable detection of faults is a significant technical challenge in transient-based protection for a modular multi-level converter(MMC)based high voltage direct current(HVDC)system.This is because existing p...Fast and reliable detection of faults is a significant technical challenge in transient-based protection for a modular multi-level converter(MMC)based high voltage direct current(HVDC)system.This is because existing protection schemes rely heavily upon setting a complicated protective threshold,the failure of which causes high DC-fault currents in HVDC grids,and MMC is prone to such strong transient currents.In this context,this paper proposes a DC-line fault diagnosis technique based on a tuned long-short-term memory(LSTM)algorithm to improve the response and accuracy of transient-based protection.The discrete wavelet transform(DWT)extracts the transient features of DC-line voltages in the frequency-time domain.Many healthy and faulty samples are incorporated during training even by considering the noise influence.After training,numerous test samples are run to evaluate the proposed algorithm’s robustness under various fault conditions.Test results show the proposed algorithm can detect DC faults and has a high recognition accuracy of 98.6%.Compared to contemporary techniques,it can perform well to identify DC-line faults because of the efficient training of characteristic features.展开更多
基金Sponsored by Land Use Planning Database Construction Program of Licheng District,Jinan City
文摘Farmland and primary farmland protection are important contents of land management and land use planning of China. In the new round of land use planning and database construction, primary farmland protection zones are required to have high integrity and connectivity. Using landscape pattern indexes, the integrity and connectivity of primary farmland protection zones was studied in Licheng District of Jinan City. The results showed that, except patch area standard deviation, the other indexes including average patch area, patch area variation coefficient, patch edge density, largest patch index, and mean euclidean nearest-neighbor, all indicate high connectivity of primary farmland protection zones after layout adjustment. A simple and convenient method for identifying the integrity and connectivity of primary farmland protection zones was supplied.
基金the National Natural Science Foundation of China under Grant 51977041.
文摘Fast and reliable detection of faults is a significant technical challenge in transient-based protection for a modular multi-level converter(MMC)based high voltage direct current(HVDC)system.This is because existing protection schemes rely heavily upon setting a complicated protective threshold,the failure of which causes high DC-fault currents in HVDC grids,and MMC is prone to such strong transient currents.In this context,this paper proposes a DC-line fault diagnosis technique based on a tuned long-short-term memory(LSTM)algorithm to improve the response and accuracy of transient-based protection.The discrete wavelet transform(DWT)extracts the transient features of DC-line voltages in the frequency-time domain.Many healthy and faulty samples are incorporated during training even by considering the noise influence.After training,numerous test samples are run to evaluate the proposed algorithm’s robustness under various fault conditions.Test results show the proposed algorithm can detect DC faults and has a high recognition accuracy of 98.6%.Compared to contemporary techniques,it can perform well to identify DC-line faults because of the efficient training of characteristic features.
