基于PMU相量的次/超同步间谐波识别方法

Subsynchronous and Supersynchronous Inter-Harmonic Identification Method Based on Phasor Measurements

新能源的集中并网以及直流输电的快速建设使电力电子设备在电力系统中大规模应用,导致越来越多的次/超同步间谐波被引入电网,严重影响新能源的发展与电力系统的安全。PMU因其测量的同步性、快速性和精确性使大面积监测间谐波的产生、传播和分布成为可能,可为后续的间谐波抑制与控制提供基础。推导了含有间谐波信号的单相及三相瞬时功率表达式,揭示了基于瞬时功率的间谐波监测的局限性。提出了含有间谐波的相量表达式,揭示了间谐波对相量幅值、相角及其复数形式的影响机理。进一步,提出了基于PMU测量相量的间谐波识别方法,并在广域同步测量系统(wide-area measurement system,WAMS)主站上进行了实现。利用中国西部某新能源汇集地区,因间谐波的大量存在导致火电机组次同步振荡事件的现场实际数据,验证了理论分析的正确性与提出的监测方法的有效性。

More and more inter-harmonics are brought to power grid due to integration of renewable energy and large-scale deployment of the electronic devices. This may lead to exacerbation of power system stability. Synchronization and high reporting rates of phasor measurement units（PMUs） make them an effective tool monitoring appearance, propagation and distribution of inter-harmonics for protection and control strategies. In this paper, instantaneous single-phase and three-phase powers containing inter-harmonics are analysed. Limitation of inter-harmonic monitoring based on instantaneous powers is revealed. The signal phasor containing inter-harmonics is disclosed. Then, an inter-harmonic identification method based on PMU phasor measurements is proposed. This method is implemented in a main station of wide-area measurement system（WAMS）. A number of field data is used to verify correctness of the theoretical analysis.