An Under-frequency Load Shedding Scheme with Continuous Load Control Proportional to Frequency Deviation
An Under-frequency Load Shedding Scheme with Continuous Load Control Proportional to Frequency Deviation
复制标题
与频率偏差成比例的连续负荷控制的低频减载方案
DOI：
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发表时间：
2017
期刊：
影响因子：
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通讯作者：
Yawei Yu
中科院分区：
文献类型：
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作者：
Changgang Li;Yanli Sun;Yawei Yu
低频减载（UFLS）是解决负荷产生不平衡引起的频率下降的重要措施。在现有的方案中，继电器以不连续的方式卸载负载，这是导致欠脱落和过脱落问题的主要原因。随着电力电子技术的应用，一些负载可以连续控制，从而使连续负载的UFSL改进成为可能。本文提出了一种连续减载的UFLS方案。暂态过程中，在频率达到最小值之前，减载量与频率偏差成正比。利用解析系统频响模型分析了该方案的可行性。讨论了调速器下垂、系统惯性和频率阈值对UFLS方案性能的影响。通过与传统UFLS方案的比较，验证了该方案的有效性。
Under frequency load shedding (UFLS) is an important measure to tackle with frequency drop caused by load-generation imbalance. In existing schemes, loads are shed by relays in a discontinuous way, which is the major reason leading to under-shedding and over-shedding problems. With the application of power electronics technology, some loads can be controlled continuously, and it is possible to improve the UFSL with continuous loads. This paper proposes an UFLS scheme by shedding loads continuously. The load shedding amount is proportional to frequency deviation before frequency reaches its minimum during transient process. The feasibility of the proposed scheme is analysed with analytical system frequency response model. The impacts of governor droop, system inertia, and frequency threshold on the performance of the proposed UFLS scheme are discussed. Cases are demonstrated to validate the proposed scheme by comparing it with conventional UFLS schemes.