铁磁谐振是由铁心电感元件，如发电机、变压器、电压互感器、电抗器、消弧线圈等系统的电容元件，如输电线路、电容补偿器等形成共谐条件，激发持续的铁磁谐振，使系统产生谐振过电压。
Ferromagnetic resonance is composed of core components such as inductors, capacitors, transformers, generator voltage transformer, reactor, arc suppression coil system, such as the formation conditions of resonant transmission lines, capacitance compensator, excitation ferroresonance continuously, make the system resonance overvoltage.
电力系统的铁磁谐振可分二大类：一类是在66kV及以下中性点绝缘的电网中,由于对地容抗与电磁式电压互感器励磁感抗的不利组合,在系统电压大扰动（如遭雷击、单相接地故障消失过程以及开关操作等）作用下而激发产生的铁磁谐振现象；另一类是发生在220kV（或110kV）变电站空载母线上，当用220kV、110kV带断口均压电容的主开关或母联开关对带电磁式电压互感器的空母线充电过程中，或切除（含保护整组传动联跳）带有电磁式电压互感器的空母线时，操作暂态过程使连接在空母线上的电磁式电压互感器组中的一相、两相或三相激发产生的铁磁谐振现象，即串联谐振，简单地讲就是由高压断路器电容与母线电压互感器的电感耦合产生谐振由于谐振波仅局限于变电站空载母线范围内，也称其为变电站空母线谐振
Ferroresonance in power system can be divided into two categories: one is the insulation of 66kV and below the neutral point of the power grid, due to unfavorable combination of capacitance and electromagnetic voltage transformer excitation inductance, voltage disturbance in the system (such as lightning, the disappearance of the single-phase ground fault process and switch operation function) under the excitation of ferromagnetic resonance phenomenon; the other is in 220kV (or 110kV) substation bus load, when using the 220kV and 110kV with the grading capacitor of the main switch or bus connection switch for busbars with electromagnetic voltage transformer in the charging process, or resection (including the protection group drive intertrip) empty bus with electromagnetic voltage transformer, the transient process of the operation of the Ferroresonance in empty bus connected electromagnetic voltage transformer in one phase, two-phase or three-phase excited, namely harmonic series Simply speaking, the resonance between the high-voltage circuit breaker capacitor and the busbar voltage transformer induces resonance, because the resonance wave is only limited to the range of the substation's no-load bus, also known as the substation air bus resonance.