电力系统低频减载方案设计.docVIP

摘 要 低频减载是防止电力系统频率下降，维护系统频率稳定的有效措施。当系统发生故障时，及时的切除一定的负荷能够使得频率尽快回升到正常工作范围之内，从而保证系统稳定的运行。 本文通过理论的推导以及仿真总结了电力系统频率静态特性以及动态特性的一些特点，比如电力系统频率的静态特性对系统频率的变化具有抑制的作用；电力系统频率的动态特性比较复杂，具有时空分布的特性，并且与系统的结构、运行方式都有着密切的关系。 本文提出一种基于动态频率积分的低频减载方案，该方案能够自适应的确定首级动作频率，每轮减载量等，并且可以避免多机系统中频率振荡的影响。针对怎样把整定的每轮减载量合理的分配到每个节点，本文提出了一种基于有功功率缺额灵敏度的减载量分配方案，该灵敏度能有效的反映切除某负荷节点对频率恢复的作用，通过仿真，验证了每轮减载量的整定以及切负荷量分配方案的有效性。 在实际的低频减载方案中，不仅要考虑负荷节点的功率灵敏度，而且要考虑各个负荷节点的重要程度，切负荷成本等因素。因此，本文通过熵值法来综合考虑各个因素的影响，从而得出在综合权重下的切负荷顺序。利用算例进行仿真，仿真结果表明所提出的减载方案能够考虑多方面的因素，并且使得频率恢复到较好的程度。因此，该方法的减载效果优于传统方案。 关键词 电力系统；低频减载；有功缺额灵敏度；熵值法 Abstract Under Frequency Load Shedding (UFLS) is an effective method to prevent the frequency reduction and maintain stability of power system. When system collapses, it will help the frequency back up to the normal range quickly by dropping excessive load in time. this paper summarizes the static and dynamic characteristics of frequency in power system with theoretical deduction and stimulation. For instance, the static characteristic of frequency exerts inhibiting effect on the change of system frequency; the dynamic characteristic of frequency is more complex due to its time and space distribution features. In addition, it has a close relationship with the system structure and operation mode. This paper proposes an UFLS scheme based on the dynamic frequency of integral.This scheme can determine the first action frequency and the amount of load shedding each round automatically and it can avoid the negative effect of frequency oscillation in multi-machine power systems. To assign the setting load shedding amount each round to each code reasonably, this paper focuses on the distribution of load shedding amount based on the sensitivity of the active power vacancy. This sensitivity can reflect the effect of removing certain load node on frequency recovery . With the simulation process, it verifies the effectiveness of the setting load shedding each round and the distribution scheme of load shedding. Nev