谐波的产生与危害

谐波的产生与危害 Harmonics
谐波
 
Introduction
In recent years, the modernization of industrial processes and the growing application of electrical machines and equipment have led to major develop- ments in power electronics:
这些年由于工业过程的现代化和电子设备仪器的应用，带来了电力电子的快速发
展。
Semi-conductor-based systems (transistors, thyristors, etc.) designed for:
• Static power converters: AC/DC
• Rectifiers
• Inverters
• Frequency converters
• And many other multi-cycle or phase controlled devices
These systems represent “non-linear” loads for electrical supplies. A “non-linear” load is a load for which the current consumption does not reflect the supply voltage(although the voltage of the source imposed on the load is sinusoidal, the current consumption is not sinusoidal).
半导体系统(晶体管，晶闸管)设计用于:
•静态的电力转换器:AC/DC
•整流器
•喀什变压器
•频率转换器
•其它多种循环或相数控制装置
这些系统代表电力供应的“非线性”负荷。它是指消耗的电流不能反映在电源电
压上（尽管负荷作用上的电压是正弦曲线的，而消耗的电流是非正弦曲线的）。
 
Other “non-linear’ loads are also present in electrical installations, in particular:
• Variable impedance loads, using electric arcs: arc furnaces, welding units, fluorescent tubes, discharge lamps, etc.
• Loads using strong magnetizing currents: saturated transformers, inductors, etc.
其它“非线性”负荷也表现在电力安装上,主要有:
• 变化的阻抗负荷，如使用电弧，焊接设备，日光灯管，放电管等
• 使用强磁场电流的负荷,如饱和喀什变压器, 电感器等
 
The FOURIER decomposition (harmonic analysis) of the current consumption of a non-linear receiver shows:
• The fundamental, a sinusoidal term at the 50Hz mains supply frequency
• The harmonics, sinusoidal terms whose frequencies are multiples of the fundamental frequency 

傅立叶级数对受到的非线性负荷所消耗的电流（以谐波分析的方式）分解(见以
上公式)。
•基本的正弦曲线条件在 50HZ的供应频率下
•谐波的正弦曲线条件在基本频率的倍数条件下
These harmonic currents circulate in the source. The harmonic impedances of the source then give rise to harmonic voltages, according to the equation: 
 
The harmonic currents give rise to most of the harmonic voltages causing the overall harmonic distortion of the supply voltage.
谐波的电流在范围内循环。谐波的阻抗引起谐波电压的升高 (见以上公式)。谐波的电流又引起了大多数谐波电压的升高，导致整个电源电压的谐波畸变。 
   
∑:sum of all the harmonic currents from harmonic 2 (50Hz X 2) to the last harmonic n (50Hz X n) JIANGSU LTEC ELECTRIC CO., LTD.
 
The effect of harmonics
谐波的影响
 
•Influence the stability of power supply system. The power line and transformer in network generally adopts electromagnetic relay, inductive relay or micro processor-based protection system. They all belong to sensitive parts, and easily go into malfunction with a high level of harmonic pollution.
Therefore, the stability and safe operation in power supply will be threatened.
 影响供电系统的稳定性: 电力线路和喀什变压器通常采用电磁继电器，感应式继电器或微机保护系统。在系统中这些都属于敏感元件，在受到高次谐波的影响后容易产生误操作。这样谐波严重威胁了电力供应系统的稳定和安全运行。
 
•Influence the quality of power grid. The high level pollution of harmonic could involve the distortion of voltage and current waveform. In addition, the active power and reactive power generated by the same frequency of harmonic voltage and current will reduce the voltage in grid, increase the line loss, and dissipate the power capacity.
 影响了电网的质量: 高次谐波能使电网中的电压和电流波形发生畸变。另外相同频率的谐波电压和电流会产生同次谐波的有功功率和无功功率，从而降低电网的电压，增加线路损耗，浪费电网的容量。