目前我国已形成东北—华北(含山东)—华中(含川渝)跨区同步互联电网。采用电力系统暂态稳定时域仿真程序和自动低频减负荷方案设计了单机计算模型，全面分析和评价了各种联网或孤网运行模式下发生大功率缺额时，电网频率暂态稳定特性及各电网现有低频减载方案对2005—2007年电网频率安全运行的适应性。在此基础上提出了我国东北—华北—华中跨区互联电网统一协调的低频自动减负荷方案，该方案不但适用于各种联网模式，也适用于各种孤网模式。当受到5%~45%的不同功率缺额扰动时，互联电网能够相应地协调减负荷，保证了最小频率不低于48.0 Hz，满足频率恢复速度10 s左右恢复到49.5 Hz，达到了统一协调减载，保证系统频率稳定和联络线及大机组安全。

At present an interareal synchronization interconnected power grid that consists of Northeast China power grid, North China power grid involving Shandong power system and Central China power grid involving Shichuan-Chongqing power grid is formed. By use of time-domain power system transient stability simulation program and automatic under-frequency load shedding (UFLS) scheme, a single-machine calculation model is designed, by which the transient stability characteristics of power system frequency under various interconnected operation modes or isolated operation mode as well as the adaptability of existing UFLS schemes adopted in various power grids to secure operation of power grid frequency from 2005 to 2007 are overall analyzed and evaluated while large amount of power shortage occurs. On this basis a coordinative UFLS scheme for above-mentioned interareal synchronization interconnected power grid is proposed, this scheme is not only suitable to different interconnection modes, but also to various isolated operation modes. When the disturbances of power shortages from 5% to 45% happen, the interconnected power grid can perform coordinative load shedding correspondingly to ensure that the lowest power frequency is not lower than 48.0 Hz and power frequency can be recovered to 49.5 Hz within 10 seconds. Thus, the unified coordinative load shedding can be implemented, and system frequency stability as well as the security of tie-lines and large capacity units can be ensured.

[3] DL 755-2001，电力系统安全稳定导则[S]． [4] SD131-84，电力系统技术导则[S]． [5] 2006年国家电网公司系统电网运行方式分析[R]．北京：国家电力调度通信中心，2006． [6] 华北、东北、华中、山东、川渝电网2005年，2006年运行方式报告[R]．北京：2005，2006． [7] 刘肇旭，赵强，卜广全．全国互联电网系统频率特性及低频减载方案研究[R]．北京：中国电力科学研究院，2006． [8] 刘肇旭，马腾，卜广全．南方互联电力系统联合低频减负荷方案研究[R]．北京：中国电力科学研究院，1997． [9] Underfrequency Issues Work Group．WSCC technical studies subcommittee coordinated off-nominal frequency load shedding and restoration planfinal report[R]．2005． [10] Nestern Systems Coordinating Council．Underfrequency load shedding relay application guide[R]．1974． [11] 袁季修．防止电力系统频率崩溃的紧急控制[J]．电力自动化设备，2002，22(4)：1-4． Yuan Jixiu．Emergency control for preventing frequency collapse of power system[J]．Electric Power Automation Equipment，2002，22(4)：1-4(in Chinese)． [12] 袁季修．试论防止电力系统大面积停电的紧急控制—电力系统安全稳定运行的第三道防线[J]．电网技术，1999，23(4)：1-4． Yuan Jixiu．Emergency control for preventing widespread blackout of power system-the third line of defence[J]．Power System Technology，1999，23(4)：1-4(in Chinese)． [13] 王葵，潘贞存．一种新型低频减载方案的研究[J]．电网技术，2001，25(6)：31-33． Wang Kui，Pan Zhencun．A new load shedding scheme for limiting underfrequency[J]．Power System Technology，2001，25(6)：31-33(in Chinese)． [14] 樊福而．大电网互联系统的频率与潮流问题[J]．电网技术，2000，24(6)：25-28． Fan Fuer． Frequency and power flow of interconnected large power system[J]．Power System Technology，2000，24(6)：25-28(in Chinese)． [15] 王漪，王钢．电力系统异步运行时频率动态过程的计算分析[J]．电网技术，1994，18(3)：35-38． Wang Yi，Wang Gang．Calculation and analysis of frequency dynamics for asynchronous status[J]．Power System Technology，1994，18(3)：35-38(in Chinese)． [16] 熊小伏，周永忠，周家启．计及负荷频率特性的低频减载方案研究[J]．中国电机工程学报，2005，25(19)：48-51． Xiong Xiaofu，Zhou Yongzhong，Zhou Jiaqi．Study of underfrequency load shedding scheme based on load frequency characteristics [J]．Proceedings of the CSEE，2005，25(19)：48-51(in Chinese)． [17] 魏庆海，鲁顺，范东春，等．东北电网频率与联络线潮流的关系[J]．电网技术，2004，28(6)：22-25． Wei Qinghai，Lu Shun，Fan Dongchun，et al．Relation of frequency in Northeast power grid to power flow in tie-line between Northeast and North China Grids[J]．Power System Technology，2004，28(6)：22-25(in Chinese)． [18] 吴杰康．在暂态过程中电力系统频率的估算[J]．中国电机工程学报，2005，25(7)：70-74． Wu Jiekang．Frequency estimation of power systems in transient processes[J]．Proceedings of the CSEE，2005，25(7)：70-74(in Chinese)． [19] 郭钰锋，于达仁，赵婷，等．电网频率的非正态概率分布特性[J]．中国电机工程学报，2008，28(7)：26-31． Guo Yufeng，Yu Daren，Zhao Ting，et al．Characteristics of power system frequency abnormal distribution[J]．Proceedings of the CSEE，2008，28(7)：26-31(in Chinese)． [20] 赵庆波，曾鸣，刘敏，等．电力市场中的负荷频率控制方案研究[J]．中国电机工程学报，2002，22(11)：45-50． Zhao Qingbo，Zeng Ming，Liu Min，et al．Research on controlling approaches to load frequency in electricity market[J]．Proceedings of the CSEE，2002，22(11)：45-50(in Chinese)． [21] Kunder P．Power system stability and control[M]．New York：McGraw-Hill，1993． [22] Girgis A A，Peterson W L．Adaptive estimation of power system frequency deviation and its rate of change for calculating sudden power system overloads[J]．IEEE Trans on Power Delivery，1990，l5(2)：585-592． [23] 王丽敏，刘肇旭．自动低频减负荷方案设计单机模型程序说明[Z]．北京：中国电力科学研究院，2006． [24] 曾启明，陈伟乐，谢志堂，等．电力系统频率新的跟踪算法[J]．中国电机工程学报，2004，24(6)：70-72． Zeng Qiming，Chen Weile，Xie Zhitang，et al．A new tracking algorithm for power system frequency[J]．Proceedings of the CSEE，2004，24(6)：70-72(in Chinese)． [25] Maliszewski R M，Dunlop R D，Wilson G L．Frequency actuated load shedding and restoration Part I – Philosophy[J]．IEEE Trans on Power Apparatus and Systems，1971 (90)：1452-1459． [26] 李永庄，卜广全，刘肇旭，等．Study on CEM power system underfrequency load shedding scheme in 2006-2007 operation[R]．北京：中国电力科学研究院，2006．