把电看作是水，水里面有杂质，电里面也会有杂质，电里面的杂质称之为谐波。只要电的频率不是50Hz，都叫做谐波，其中额定频率为基波频率偶数倍的谐波，称为“偶次谐波”。

谐波会造成哪些危害呢？

1、对继电保护和自动装置的信号产生干扰造成误动作；

2、引起电容器组谐振和谐波电流放大，导致电缆线路过负荷；

3、使变压器，电动机等设备产生附加损耗，引起发热现象，导致绝缘损坏；

4、使感应式测量仪表产生计量误差。

如何减少谐波的影响呢？

1、减少非线性负载的使用，如：变频器和电子设备，降低谐波源的产生；

2、提升电压等级和扩大设备容量，提高电网对谐波的抗性；

3、使用谐波抑制装置来减少谐波，提高电能质量以及设备运行的稳定性。

What are even harmonics and how to control it?

Think of electricity as water, just as water can contain impurities, Electricity can also contain  impurities, these impurities in electricity are called harmonics.Any electrical frequency that is not 50Hz, is called a harmonic, Among these, harmonics with frequencies that are even multiples of the fundamental frequency are referred to as "even-order harmonics".

What are the potential hazards of harmonics?

1、Interference with signals of relay protection and automatic devices, causing maloperation;

2、Triggering resonance and harmonic current amplification in capacitor banks, leading to overload conditions in cable circuits;

3、Generating additional losses in equipment such as transformers and motors, causing heating effects that lead to insulation damage;

4、Causing metering errors in induction-type measuring instruments.

How to reduce the impact of harmonics?

1、Reduce the use of non-linear loads (e.g., variable frequency drives and electronic equipment), to minimize harmonic generation at the source;

2、Raise voltage levels and expand equipment capacity to enhance the power grid's immunity to harmonics;

3、Utilize harmonic suppression devices to reduce harmonics, improve power quality, and enhance operational stability of equipment.