基于LC振荡频率变化量的电容器组早期故障在线智能预警方法及其实现

Power capacitor banks failure warning method based online intelligence LC oscillation frequency variation and its implementation

电容器组是电网中的重要设备,常有内部轻微故障的发生,若无法及时发现,将逐步发展为严重故障,导致电容器组的损坏。为解决此问题,根据电容器组早期单个元件损坏的理论特征分析,提出了针对电容器组早期内部元件故障的一个全新的预警方法:LC振荡频率变化量法。该方法通过采集放电PT电压和母线电压,计算出串联电抗器与电容器形成的LC回路的振荡频率,记录该频率初始值。再通过电容器运行过程中该频率的变化量进行预警判断。该方法的优点是判别精度高,且能判断出故障相别,可以躲过系统电压的波动。根据预警方法的需求,设计了专用的电容器组的在线监测和预警装置,并将这些方法实现了工程应用。通过现场运行的各种数据也验证了所提新的预警方法。该装置方便了电容器组的运行管理,并为其早期故障的及时发现提供了新的途径。

Power capacitor bank is an important device, when it occurs a minor fault, if not be found in time, will gradually develop into a serious malfimction, causing damage to the capacitor bank. To solve this problem, this paper proposes a new method of early capacitor bank internal component failure warning： the LC oscillation frequency variation method based on early theoretical characteristics of a single component damage analysis. The method calculates the oscillation frequency by collecting discharge PT voltage and bus voltage, records the frequency of initial value, and then compares the variation in the process to propose early warning. The advantages of this method are of high detection precision, and can judge the fault phase and avoid the system voltage fluctuation. According to the warning method needs, an on-line monitoring and early warning device of capacitor bank is designed to realize the engineering applications of this method. A variety of data after the field operation also verify this warning method. Thus this device is convenient for the operation and the management of the capacitor banks, and provides a new way to find the early fault in time.