| 引用本文: | 李 猛,卫云辉,张豆豆,等.基于动态状态估计的海风柔性低频输电系统海缆纵联保护[J].电力系统保护与控制,2025,53(12):1-12.[点击复制] |
| LI Meng,WEI Yunhui,ZHANG Doudou,et al.Pilot protection of submarine cables in flexible low frequency transmission systems for offshore wind power based on dynamic state estimation[J].Power System Protection and Control,2025,53(12):1-12[点击复制] |
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| 摘要: |
| 柔性低频交流输电技术兼具工频与直流输电的优势，在中远海风电领域应用潜力巨大。但该场景下风电采用长距离海缆送出，当海缆发生故障后，其故障电流特征受双端受控电源的影响，导致电流差动保护性能下降，且低频周期长，叠加长海缆分布电容的影响，该保护故障判别时间缓慢，易导致风机脱网，威胁电网安全稳定运行。提出了基于动态状态估计的海上风电柔性低频输电系统海底电缆纵联保护原理。搭建了考虑三芯海缆各金属层结构和分布电容的海缆模型。利用瞬时值的动态状态估计冗余特性提升了保护的速动性和可靠性。并通过所建海缆模型与物理海缆的匹配程度构造保护判据。仿真结果表明，所提保护方法能够在5 ms内可靠判别各种类型的区内、外故障，并具有较好的耐过渡电阻和抗干扰能力。 |
| 关键词: 海上风电 柔性低频输电系统 三芯海缆 动态状态估计 纵联保护 |
| DOI：10.19783/j.cnki.pspc.241067 |
| 投稿时间：2024-08-09修订日期：2024-11-11 |
| 基金项目:国家自然科学基金面上项目资助(52377070) |
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| Pilot protection of submarine cables in flexible low frequency transmission systems for offshore wind power based on dynamic state estimation |
| LI Meng1,WEI Yunhui1,ZHANG Doudou1,WANG Haoyue1,NIE Ming2,HE Jinghan1 |
| (1. School of Electrical Engineering, Beijing Jiaotong University, Beijing 100044, China;
2. State Grid Economic and Technological Research Institute Co., Ltd., Beijing 102209, China) |
| Abstract: |
| Flexible low frequency AC transmission technology combines the advantages of both conventional AC power frequency and DC transmission, offering significant potential for application in medium-to-long distance offshore wind power connection. However, in such scenarios, wind power is transmitted through long-distance submarine cables. In the event of a cable fault, the fault current characteristics are influenced by the controlled power sources at both ends, leading to a decline in the performance of current differential protection. Additionally, the long low-frequency period, coupled with the effect of the distributed capacitance of the long submarine cable, results in slow fault discrimination for the protection system. This can cause wind turbines to disconnect from the grid, threatening grid security and stability. To address this, a pilot protection scheme for submarine cables in offshore wind power flexible low frequency transmission systems is proposed based on dynamic state estimation. A submarine cable model is established considering the structure of each metallic layer of a three-core submarine cable and its distributed capacitance. By utilizing the redundancy characteristics of dynamic state estimation of instantaneous values, the speed and reliability of the proposed protection method are improved. A protection criterion is constructed based on the matching degree between the developed cable model and the physical cable. Simulation results show that the proposed protection method can reliably discriminate various internal and external faults within 5 ms and exhibits strong tolerance to transition resistance and interference. |
| Key words: offshore wind power flexible low frequency transmission system three-core submarine cable dynamic state estimation pilot protection |
