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| 諧波的產生與危害 |
| 2015/8/29 admin |
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Harmonics
諧波
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:
這些年由于工業過程的現代化和電子設備儀器的應用，帶來了電力電子的快速發
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).
半導體系統(晶體管，晶閘管)設計用于:
•靜態的電力轉換器:AC/DC
•整流器
•變頻器
•頻率轉換器
•其它多種循環或相數控制裝置
這些系統代表電力供應的“非線性”負荷。它是指消耗的電流不能反映在電源電
壓上（盡管負荷作用上的電壓是正弦曲線的，而消耗的電流是非正弦曲線的）。
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“非線性”負荷也表現在電力安裝上,主要有:
• 變化的阻抗負荷，如使用電弧，焊接設備，日光燈管，放電管等
• 使用強磁場電流的負荷,如飽和變壓器, 電感器等
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
傅立葉級數對受到的非線性負荷所消耗的電流（以諧波分析的方式）分解(見以
上公式)。
•基本的正弦曲線條件在 50HZ的供應頻率下
•諧波的正弦曲線條件在基本頻率的倍數條件下
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.
諧波的電流在范圍內循環。諧波的阻抗引起諧波電壓的升高 (見以上公式)。諧波的電流又引起了大多數諧波電壓的升高，導致整個電源電壓的諧波畸變。
∑: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
諧波的影響
•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.
影響供電系統的穩定性: 電力線路和變壓器通常采用電磁繼電器，感應式繼電器或微機保護系統。在系統中這些都屬于敏感元件，在受到高次諧波的影響后容易產生誤操作。這樣諧波嚴重威脅了電力供應系統的穩定和安全運行。
•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.
影響了電網的質量: 高次諧波能使電網中的電壓和電流波形發生畸變。另外相同頻率的諧波電壓和電流會產生同次諧波的有功功率和無功功率，從而降低電網的電壓，增加線路損耗，浪費電網的容量。
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