电力系统中有许多铁芯电感元件，如变压器，互感器等这些大都是非线性元件。他们和系统的电容组成许多的振荡回路。如果满足一定的条件，就可能激发时间很长铁磁谐振过电压。将产生很大的过电流和电压。记忆损坏设备，威胁人员安全。消谐装置实时监测电压互感器PT开口三角处的电压和频率，当发生铁磁谐振时，瞬时启动谐振元件，产生强大阻尼，消除谐振。微机消谐装置大多采用单片机作为核心元件，对PT开口三角电压（即零序电压）进行循环检测。正常工作情况下，该电压小于30V，装置内的大功率消谐元件（可控硅）处于阻断状态，对系统无任何影响。当PT开口三角电压大于30V时，说明系统出现故障。装置开始对开口三角电压进行数据采集。通过数字测量、滤波、放大等数字信号处理技术，对数据进行分析、计算，判断出当前的故障状态。如果出现某种频率的铁磁谐振（一般在17Hz--150Hz之间），CPU立即启动消谐电路（使可控硅导通），让铁磁谐振在强大的阻尼下迅速消失。铁磁谐振消除后，CPU作相应纪录、存储，并自动报警、显示有关谐振信息(包括发生时间、频率、幅值等)如果是过电压或单相接地，CPU做出诊断后，装置分别给出显示和报警，并自动纪录、存储有关故障信息。最后，CPU返回初始状态，并继续检测开口三角电压。
There are many iron core inductance components in power system, such as transformers, transformers and so on, which are mostly non-linear components. They form many oscillating circuits with the capacitance of the system. If certain conditions are satisfied, the ferroresonance overvoltage may be excited for a long time. It will produce large overcurrent and voltage. Memory damage equipment, threatening the safety of personnel. The harmonic elimination device monitors the voltage and frequency of PT open triangle in real time. When ferromagnetic resonance occurs, the resonant element is instantaneously activated, which generates strong damping and eliminates resonance. Microcomputer harmonic elimination devices mostly use single chip computer as the core component to detect the open triangular voltage (zero sequence voltage) of PT. Under normal working conditions, the voltage is less than 30V, and the high-power harmonic elimination element (thyristor) in the device is blocked, which has no effect on the system. When the open triangle voltage of PT is greater than 30V, the system fails. The device began to collect the open triangle voltage data. Through digital measurement, filtering, amplification and other digital signal processing technology, the data are analyzed and calculated, and the current fault state is judged. If a certain frequency of ferroresonance (usually between 17 Hz and 150 Hz) occurs, the CPU immediately starts the harmonic elimination circuit (to turn on the thyristor), so that the ferroresonance disappears rapidly under strong damping. After the elimination of ferroresonance, the CPU records and stores the corresponding information, and automatically alarms and displays the relevant resonance information (including occurrence time, frequency, amplitude, etc.). If the CPU is overvoltage or single-phase grounding, after the CPU diagnoses, the device gives display and alarm respectively, and automatically records and stores the relevant fault information. Finally, the CPU returns to its initial state and continues to detect the open triangle voltage.