諧波畢業(yè)設(shè)計(jì)英文文獻(xiàn)翻譯

1、<p><b>　　Harmonics</b></p><p>　　Service reliability and quality of power have become growing concerns for many facility managers, especially with the increasing sensitivity of electronic equ

2、ipment and automated controls. There are several types of voltage fluctuations that can cause problems, including surges and spikes, sags, harmonic distortion, and momentary disruptions. Harmonics can cause sensitive equ

3、ipment to malfunction and other problems, including overheating of transformers and wiring, nuisance breaker trips, and re</p><p>　　What Are Harmonics?</p><p>　　Harmonics are voltage and current

4、 frequencies riding on top of the normal sinusoidal voltage and current waveforms. Usually these harmonic frequencies are in multiples of the fundamental frequency, which is 60 hertz (Hz) in the US and Canada. The most c

5、ommon source of harmonic distortion is electronic equipment using switch-mode power supplies, such as computers, adjustable-speed drives, and high-efficiency electronic light ballasts. </p><p>　　Harmonics ar

6、e created by these “switching loads” (also called “nonlinear loads,” because current does not vary smoothly with voltage as it does with simple resistive and reactive loads): Each time the current is switched on and off,

7、 a current pulse is created. The resulting pulsed waveform is made up of a spectrum of harmonic frequencies, including the 60 Hz fundamental and multiples of it. This voltage distortion typically results from distortion

8、in the current reacting with system impedance. (</p><p>　　Harmonic waveforms are characterized by their amplitude and harmonic number. In the U.S. and Canada, the third harmonic is 180 Hz—or 3 x 60 Hz—and th

9、e fifth harmonic is 300 Hz (5 x 60 Hz). The third harmonic (and multiples of it) is the largest problem in circuits with single-phase loads such as computers and fax machines. Figure 1 shows how the 60-Hz alternating cur

10、rent (AC) voltage waveform changes when harmonics are added. </p><p>　　The Problem with Harmonics</p><p>　　Any distribution circuit serving modern electronic devices will contain some degree of

11、harmonic frequencies. The harmonics do not always cause problems, but the greater the power drawn by these modern devices or other nonlinear loads, the greater the level of voltage distortion. Potential problems (or symp

12、toms of problems) attributed to harmonics include:</p><p>　　Malfunction of sensitive equipment</p><p>　　Random tripping of circuit breakers</p><p>　　Flickering lights</p><

13、;p>　　Very high neutral currents</p><p>　　Overheated phase conductors, panels, and transformers</p><p>　　Premature failure of transformers and uninterruptible power supplies (UPSs)</p>

14、<p>　　Reduced power factor</p><p>　　Reduced system capacity (because harmonics create additional heat, transformers and other distribution equipment cannot carry full rated load)</p><p>　　I

15、dentifying the Problem</p><p>　　Without obvious symptoms such as nuisance breaker trips or overheated transformers, how do you determine whether harmonic current or voltages are a cause for concern? Here are

16、 several suggestions for simple, inexpensive measurements that a facility manager or staff electrician could take, starting at the outlet and moving upstream:</p><p>　　■ Measure the peak and root mean square

17、 (RMS) voltage at a sample of receptacles. The “crest factor” is the ratio of peak to RMS voltage. For a perfectly sinusoidal voltage, the crest factor will be 1.4. Low crest factor is a clear indicator of the presence o

18、f harmonics. Note that these measurements must be performed with a “true RMS” meter—one that doesn’t assume a perfectly sinusoidal waveform.</p><p>　　■ Inspect distribution panels. Remove panel covers and vi

19、sually inspect components for signs of overheating, including discolored or receded insulation or discoloration of terminal screws. If you see any of these symptoms, check that connections are tight (since loose connecti

20、ons could also cause overheating), and compare currents in all conductors to their ratings.</p><p>　　■ Measure phase and neutral currents at the transformer secondary with clamp-on current probes. If no harm

21、onics are being generated, the neutral current of a three-phase distribution system carries only the imbalance of the phase currents. In a well-balanced three-phase distribution system, phase currents will be very simila

22、r, and current in the neutral conductor should be much lower than phase current and far below its rated current capacity. If phase currents are similar and neutral current ex</p><p>　　■Compare transformer te

23、mperature and loading with nameplate temperature rise and capacity ratings. Even lightly loaded transformers can overheat if harmonic current is high. A transformer that is near or over its rated temperature rise but is

24、loaded well below its rated capacity is a clear sign that harmonics are at work. (Many transformers have built-in temperature gauges. If yours does not, infrared thermography can be used to detect overheating.)</p>

25、<p>　　In addition to these simple measurements, many power-monitoring devices are now commercially available from a variety of manufacturers to measure and record harmonic levels. These instruments provide detaile

26、d information on THD, as well as on the intensity of individual harmonic frequencies. After taking the appropriate measurements to determine whether you have high levels of harmonics and, if so, to find the source, you w

27、ill be well-positioned to choose the best solution.</p><p>　　Solutions to Harmonics Problems</p><p>　　The best way to deal with harmonics problems is through prevention: choosing equipment and i

28、nstallation practices that minimize the level of harmonics in any one circuit or portion of a facility. Many power quality problems, including those resulting from harmonics, occur when new equipment is haphazardly added

29、 to older systems. However, even within existing facilities, the problems can often be solved with simple solutions such as fixing poor or nonexistent grounding on individual equipment or </p><p>　　install d

30、evices to attenuate or remove the harmonics. Reinforcing the distribution system means installing double-size neutral wires or installing separate neutral wires for each phase, and/or installing oversized or Krated trans

31、formers, which allow for more heat dissipation. There are also harmonic-rated circuit breakers and panels, which are designed to prevent overheating due to harmonics. This option is generally more suited to new facilitie

32、s, because the costs of retrofitting an existing fa</p><p>　　Passive filters (also called traps) include devices that provide low-impedance paths to divert harmonics to ground and devices that create a highe

33、r-impedance path to discourage the flow of harmonics. Both of these devices, by necessity, change the impedance characteristics of the circuits into which they are inserted. Another weakness of passive harmonic technolog

34、ies is that, as their name implies, they cannot adapt to changes in the electrical systems in which they operate. This means that chan</p><p>　　Active harmonic filters, in contrast, continuously adjust their

35、 behavior in response to the harmonic current content of the monitored circuit, and they will not cause resonance. Like an automatic transmission in a car, active filters are designed to accommodate a full range of expec

36、ted operating conditions upon installation, without requiring further adjustments by the operator.</p><p>　　Isolation transformers are filtering devices that segregate harmonics in the circuit in which they

37、are created, protecting upstream equipment from the effects of harmonics. These transformers do not remove the problem in the circuit generating the harmonics, but they can prevent the harmonics from affecting more sensi

38、tive equipment elsewhere within the facility.</p><p>　　Harmonic mitigating transformers actually do relieve problematic harmonics. HMTs can be quite cost-effective in the right application, because they can

39、both improve reliability and reduce energy costs. The right application includes transformers that are heavily or moderately loaded and where high levels of harmonic currents are present. In addition, HMTs are very effec

40、tive in supporting critical loads that are backed up by a UPS. UPSs and backup generators tend to have high impedance, which res</p><p>　　Because of this, equipment that operates flawlessly when supplied by

41、utility power may malfunction when the backup system engages during a utility outage. Note that some of these power systems have output filters (either passive or active) to control harmonic levels. The presence or absen

42、ce of such filters should be determined before adding an HMT.</p><p>　　The Harmonics Ltd. Harmonic Suppression System is a unique solution for single-phase loads that is designed to suppress the third harmon

43、ic. An HSS is generally more expensive than an HMT, but it is designed to attenuate the harmonics problems throughout the entire distribution system, not just upstream of the transformer. The types of facilities that pre

44、sent the best opportunities for HSS installation are those that place a very high premium on power quality and reliability, such as server farms</p><p>　　Economic Evaluation</p><p>　　Evaluating

45、the life-cycle costs and effectiveness of harmonics mitigation technologies can be very challenging—beyond the expertise of most industrial facility managers. After performing the proper measurement and analysis of the h

46、armonics problem, this type of evaluation requires an analysis of the costs of the harmonics problem (downtime of sensitive equipment, reduced power factor, energy losses or potential energy savings) and the costs of the

47、 solutions. A good place to start in performing t</p><p>　　Additional Resources</p><p>　　Institute of Electrical and Electronics Engineers (IEEE),Standard 519-1992, “IEEE Recommended Practices a

48、nd Requirements for Harmonic Control in Electric Power Systems” (1992), available at www.ieee.org.</p><p>　　Relationship between harmonics and symmetrical components</p><p>　　Abstract New termin

49、ology is introduced to make clear the relationship between harmonics and symmetrical components. Three-phase sets are classified in terms of symmetrical sets and asymmetrical sets. Subclasses are introduced with the name

50、s symmetrical balanced sets, symmetrical unbalanced sets, asymmetrical balanced sets and asymmetrical unbalanced sets to show that a threephase set can resolve to either one, two or three symmetrical component sets. The

51、results from four case studies show that </p><p>　　Keywords asymmetrical sets; harmonic flows; harmonic sources; symmetrical component sets; symmetrical sets</p><p>　　Any periodic wave shape can

52、 be broken down into or analysed as a fundamental</p><p>　　wave and a series of harmonics.</p><p>　　Three-phase harmonic analysis requires a clear understanding of the relationship between symme

53、trical component injections from harmonic sources (e.g. adjustable speed drives, ASDs) and their relationship to harmonic flows (symmetrical components) arising from the application of a harmonic source to a linear syste

54、m.</p><p>　　Alimited number of references contain brief information concerning harmonics and symmetrical components. Reference 1, provides a paragraph on this topic and uses the heading ‘Relationship between

55、 Harmonics and Symmetrical Components’.It includes a table that is supported by a brief explanatory paragraph. The table expresses harmonics in terms of positive, negative and zero sequences. It states that these sequenc

56、es are for harmonics in balanced three-phase systems. The heading refers to symmetric</p><p>　　(a)Do symmetrical components (especially zero sequence), in the classical sense,</p><p>　　apply in

57、balanced as well as unbalanced non-sinusoidal systems and is this a</p><p>　　break from tradition?</p><p>　　(b)What do the terms, symmetrical, asymmetrical, balanced, unbalanced and </p>

58、<p>　　symmetrical components mean?</p><p>　　(c)What are the conditions under which a system must operate so that harmonics</p><p>　　resolve to positive, negative and zero sequences and is t

59、he table given in </p><p>　　Ref. 1 correct?</p><p>　　The terminology used is found inadequate for describing non-sinusoidal systems.</p><p>　　There is thus a need to introduce a thr

60、ee-phase terminology that will show the relationship and make the comparison between injections (currents) and harmonic flows (voltages and currents) meaningful.</p><p>　　References 3 provides the basis for

61、the solution by providing definitions for ‘threephase sets’, ‘symmetrical sets’and ‘symmetrical component sets’.</p><p>　　The purpose of this paper is to introduce an approach to harmonic analysis </p>

62、<p>　　based on the classification of three-phase sets and to make to comparison between injections from harmonic sources and corresponding harmonic flows quantifiable by expressing the results in terms of the numb

63、er of symmetrical component sets found.</p><p>　　Harmonic flows and their resolution to symmetrical components depends upon the magnitudes and phase sequences of the injections from a harmonic source, on the

64、 system’s sequence impedances, on three- and four-wire connections and on whether the customer’s linear load on the system is balanced or unbalanced. Therefore, what is injected in terms of symmetrical component sets by

65、a harmonic source is not necessarily received by the system, i.e. the harmonic flows may resolve to one, two or three symm</p><p>　　Four case studies are reported and they show a novel method for teaching th

66、e flow of power system harmonics. It is important to use case studies as part of one’s teaching as they link learning to concepts and improve understanding. They show how the method of symmetrical components can be exten

67、ded to a system’s response to harmonic flows. When taught as a group, the four case studies improve cognitive skills by showing that the symmetrical component responses under unbalanced situations are diff</p><

68、;p>　　IEEE TRANSACTIONS ON POWER ELECTRONICS VOL.19,NO.3,MAY2004</p><p><b>　　諧波</b></p><p>　　服務(wù)的可靠性和電能質(zhì)量已成為越來(lái)越多設(shè)施經(jīng)理的關(guān)注，尤其是隨著電子設(shè)備和自動(dòng)化控制靈敏度提高了很多。有幾種類(lèi)型的電壓波動(dòng)可能導(dǎo)致問(wèn)題，包括浪涌和尖峰，凹陷，諧波失真，一時(shí)中斷

69、。諧波可能導(dǎo)致敏感的設(shè)備出現(xiàn)故障和其他問(wèn)題，包括變壓器、線路和斷路器過(guò)熱傳輸滋擾，并降低功率因數(shù)。</p><p><b>　　什么是諧波？</b></p><p>　　諧波電壓和電流的頻率在正常正弦電壓和電流波形時(shí)為最佳。通常，這些諧波頻率是基本頻率，這里是60赫茲，在美國(guó)和加拿大（赫茲）的倍數(shù)。諧波失真的最常見(jiàn)的來(lái)源是使用電子設(shè)備開(kāi)關(guān)電源，如電腦，調(diào)速器，以及高效

70、率的電子燈用鎮(zhèn)流器。</p><p>　　諧波也造成了這些“開(kāi)關(guān)負(fù)載”（也稱為“非線性負(fù)載”，因?yàn)槟壳安浑S電壓變化，因?yàn)樗呛?jiǎn)單的電阻和負(fù)荷的反應(yīng)）：每次電流接通和關(guān)斷時(shí)間使電流脈沖產(chǎn)生。由此產(chǎn)生的脈沖波形組成的諧波頻率頻譜，包括60赫茲和它的倍數(shù)。從這個(gè)電壓畸變到失真，結(jié)果目前通常反應(yīng)在系統(tǒng)阻抗。（阻抗是完全對(duì)立的措施—電阻，電容和電感—交變電流。）在更高頻率的波形，統(tǒng)稱為總諧波失真（THD），不執(zhí)行任何有用的

71、工作，也可以成為重要的滋擾。</p><p>　　諧波波形的特點(diǎn)是其振幅和諧波級(jí)次。在美國(guó)和加拿大，三次諧波為180赫茲或3 × 60赫茲和第五次諧波為300赫茲（5 × 60赫茲）。第三諧波（和它的倍數(shù)）是在單相負(fù)載電路的最大問(wèn)題例如電腦和傳真。圖1顯示了60赫茲交流電（AC）電壓諧波時(shí)添加波形變化。</p><p>　　圖1：在正常的電壓或電流波形的諧波的影響 &l

72、t;/p><p>　　合并后的波形顯示加入到諧波結(jié)果 </p><p><b>　　基本的</b></p><p><b>　　聯(lián)合波形</b></p><p>　　第5第7第11和第13諧波</p><p><b>　　振幅</b></p>

73、<p><b>　　第一階段（度）</b></p><p><b>　　諧波的相關(guān)問(wèn)題</b></p><p>　　任何配電線路服務(wù)在現(xiàn)代電子設(shè)備都存在某種程度的諧波頻率。諧波并不總是導(dǎo)致問(wèn)題，但是這些現(xiàn)代設(shè)備或其他非線性負(fù)載的功率越大，電壓失真的程度就越厲害。由于諧波的潛在問(wèn)題（或者癥狀）包括：</p><p>

74、;<b>　　■敏感設(shè)備故障</b></p><p><b>　　■隨機(jī)斷路器跳閘</b></p><p><b>　　■閃爍燈</b></p><p><b>　　■非常高的中性電流</b></p><p>　　■過(guò)熱相導(dǎo)體，面板，變壓器</p&g

75、t;<p>　　■過(guò)早失效的變壓器，不間斷電源（UPS）</p><p><b>　　■降低功率因數(shù)</b></p><p>　　■降低系統(tǒng)的能力（因?yàn)橹C波創(chuàng)造更多的熱量，變壓器和其他配電設(shè)備不能進(jìn)行全額定負(fù)載）</p><p><b>　　辨別問(wèn)題</b></p><p>　　沒(méi)有明

76、顯癥狀例如斷路器和變壓器過(guò)熱的滋擾，你如何確定引起諧波電流或電壓的原因是值得關(guān)注？下面是簡(jiǎn)單的幾點(diǎn)建議，設(shè)施經(jīng)理或職員可以采取比較便宜電工測(cè)量，從插座向上檢查：</p><p>　　■測(cè)量峰值和均方根（RMS）的一個(gè)樣本的容器電壓。這“波峰因素”就是峰值比電壓。對(duì)于一個(gè)完全正弦電壓，波峰因素將是1.4倍低波峰因素是諧波的存在明確的指標(biāo)。請(qǐng)注意，這些測(cè)量必須用“真有效值”米——并不假設(shè)完全正弦波。</p>

77、;<p>　　■檢查配電板。移開(kāi)面板覆蓋 及用眼睛檢查有過(guò)熱跡象的組成部分，包括變色或消退絕緣端子螺絲。如果你看見(jiàn)任何的這些特征，檢查連接緊張（因?yàn)樗缮⒌倪B接也可導(dǎo)致過(guò)熱），并比較各導(dǎo)體電流的評(píng)級(jí)。</p><p>　　■測(cè)量階段用嵌入的探頭間接對(duì)不帶電的互感器進(jìn)行測(cè)量。如果沒(méi)有諧波生成，中性線的三相配電系統(tǒng)目前只有相電流的不平衡。在一個(gè)均衡的三相配電系統(tǒng)，相電流將非常相似，而在中性導(dǎo)體電

78、流應(yīng)遠(yuǎn)低于目前的階段，遠(yuǎn)遠(yuǎn)低于其額定電流容量。如果相電流類(lèi)似，中性線的電流大幅度的不平衡，諧波存在。如果中性電流超過(guò)百分之七十的額定值，你需要來(lái)解決問(wèn)題。</p><p>　　■比較變壓器溫度和溫度的上升和銘牌額定容量負(fù)荷。如果諧波電流高，即使是輕負(fù)載變壓器也會(huì)過(guò)熱。變壓器是接近或超過(guò)其額定溫度上升，但遠(yuǎn)低于其額定容量裝載是一個(gè)明顯的跡象，表明諧波在工作。（許多變壓器有內(nèi)置的溫度傳感器, 如果你沒(méi)有諧波，紅外熱像

79、儀可以用來(lái)檢測(cè)過(guò)熱。）</p><p>　　除了這些簡(jiǎn)單的測(cè)量，有很多電力監(jiān)控設(shè)備，現(xiàn)在市面上的生產(chǎn)廠家制造了各種測(cè)量和記錄諧波等級(jí)的儀器。這些儀器為總諧波失真提供詳細(xì)資料，以及關(guān)于個(gè)別諧波頻率的強(qiáng)度。之后采取適當(dāng)?shù)臏y(cè)量以確定是否有高水平的諧波，如果有的話，要查找原因，您需要做好充分準(zhǔn)備，選擇最佳的解決方案。</p><p><b>　　諧波問(wèn)題的解決方案</b>&l

80、t;/p><p>　　最好的處理諧波的方法是通過(guò)預(yù)防：選擇設(shè)備及安裝方法，盡量減少諧波在任何一個(gè)電路或部分設(shè)施的等級(jí)。許多電能質(zhì)量問(wèn)題，其中包括因諧波造成的，它發(fā)生在新設(shè)備隨意添加到就系統(tǒng)中。然而，即使在現(xiàn)有的設(shè)施，這些問(wèn)題通?？梢杂煤?jiǎn)單的解決方案，解決例如確定劣質(zhì)或不存在的個(gè)別設(shè)備或整個(gè)基礎(chǔ)設(shè)施，需要在分支電路之間移除一些負(fù)載，或增加額外的電路，以幫助隔離引起的諧波失真的敏感設(shè)備。如果措施解決不了這些簡(jiǎn)單的問(wèn)題，有

81、兩種基本選擇：加強(qiáng)分散系統(tǒng)承受的諧波或者安裝設(shè)備，減輕或消除諧波。加強(qiáng)分散意味著安裝雙尺寸中性線或分割每一階段單獨(dú)中性線，和/或安裝特大型或Krated變壓器，使得允許有更大的散熱量。還有諧波級(jí)斷路器和儀表盤(pán)，其目的是防止由于諧波導(dǎo)致過(guò)熱。此選擇通常更適合于新的設(shè)施，由于改型目前的設(shè)備的花費(fèi)同樣是值得注意的。減少諧波的策略，從廉價(jià)到昂貴，包括無(wú)源諧波濾波器，隔離變壓器，諧波（HMTs）減輕變壓器，由諧波有限公司提供的諧波抑制系統(tǒng)（高速鋼

82、），和有源濾波器（見(jiàn)表1）。</p><p><b>　　表1：解決諧波問(wèn)題</b></p><p>　　這里有從利弊正反兩方面解決諧波。這里列出了大致的解決辦法，以便從便宜的到昂貴的。</p><p>　　初始成本。雖然他們是最昂貴的辦法，但減輕變壓器諧波和諧波抑制系統(tǒng)可以非常經(jīng)濟(jì)。</p><p><b>

83、　　正確有效的運(yùn)用</b></p><p>　　解決辦法 最好的應(yīng)用程序 注釋</p><p>　　注：kVA = kilovol。所有費(fèi)用列出美元 來(lái)源：普氏</p><p>　　無(wú)源濾波器（也稱為陷阱）

84、，包括設(shè)備提供低阻抗路徑轉(zhuǎn)移到地面和設(shè)備設(shè)備提供了較高的阻抗路徑阻止諧波流。這兩種設(shè)備的必要性，改變他們?cè)谄渲胁迦腚娐返淖杩固匦?。另一種被動(dòng)諧波技術(shù)的缺點(diǎn)是，顧名思義，他們無(wú)法適應(yīng)其運(yùn)行電力系統(tǒng)的變化。這意味著改變電力系統(tǒng)（例如增加或去除功率因數(shù)校正電容器或更多的非線性負(fù)載）此外可能導(dǎo)致他們超負(fù)荷或引起“共振”，這實(shí)際上可以放大而不是減少諧波。</p><p>　　相反有源諧波濾波器不斷調(diào)整響應(yīng)監(jiān)測(cè)到的諧波電流的

85、大小，他們會(huì)不會(huì)引起共鳴。就像在汽車(chē)自動(dòng)變速器，有源濾波器的設(shè)計(jì)，以適應(yīng)在安裝時(shí)預(yù)期的運(yùn)行條件齊全，而無(wú)需操作員進(jìn)一步調(diào)整。</p><p>　　隔離變壓器隔離過(guò)濾設(shè)備，在其中隔離線路產(chǎn)生的諧波，保護(hù)上級(jí)設(shè)備免受諧波的影響。</p><p>　　這些變壓器不消除電路產(chǎn)生的諧波問(wèn)題，但可以防止影響到設(shè)施內(nèi)的其他地方更敏感的設(shè)備的諧波。</p><p>　　諧波能減緩解

86、壓器實(shí)際上是減少諧波問(wèn)題。HMTs的正確應(yīng)用可以帶來(lái)成本效益，因?yàn)樗鼈兗瓤梢蕴岣呖煽啃院徒档湍茉闯杀?。正確的應(yīng)用包括那些重度，中度加載和那些諧波電流水平很高的地方。此外，HMTs是非常有效的支持臨界負(fù)荷，他備份了UPS。UPS和備用發(fā)電機(jī)傾向于采用高阻抗，導(dǎo)致非線性負(fù)載的高電壓畸變。正因?yàn)槿绱嗽O(shè)備運(yùn)行完美，當(dāng)電力供應(yīng)、公用事業(yè)可能故障時(shí) 備份系統(tǒng)會(huì)在從事一種實(shí)用的工具中斷。請(qǐng)注意，這些電力系統(tǒng)的一些輸出濾波器（或主動(dòng)或被動(dòng)）控

87、制諧波的等級(jí)。是否存在這種過(guò)濾器的情況在決定之前，應(yīng)增加一個(gè)HMT的。</p><p>　　諧波的諧波有限公司。抑制系統(tǒng)是一種單相，旨在抑制三次諧波負(fù)載獨(dú)特的解決方案。通常一個(gè)HSS價(jià)格比HMT貴，但它的目的是削弱整個(gè)配電系統(tǒng)的諧波問(wèn)題，而不僅僅是上游變壓器。目前的設(shè)施，安裝了高速鋼的最有利的場(chǎng)合是那些地方對(duì)電力質(zhì)量和可靠性要求很高的地方，如服務(wù)器場(chǎng)，電臺(tái)和電視演播室，和醫(yī)院。</p><p&

88、gt;<b>　　經(jīng)濟(jì)評(píng)價(jià)</b></p><p>　　評(píng)價(jià)生命周期成本和諧波緩解技術(shù)的有效性是非常具有挑戰(zhàn)性的，超出了大多數(shù)工業(yè)設(shè)施管理人員的專(zhuān)業(yè)知識(shí)。在執(zhí)行了正確的測(cè)量和諧波問(wèn)題的分析，這種類(lèi)型的評(píng)估需要對(duì)諧波問(wèn)題的成本分析（敏感設(shè)備的停機(jī)時(shí)間，降低功率因數(shù)，能量損失或潛在的能源節(jié)約）和解決方案的成本。一個(gè)好的地方執(zhí)行這種類(lèi)型的分析是請(qǐng)當(dāng)?shù)氐墓彩聵I(yè)或提供電力援助。許多公用事業(yè)提供自己的

89、電能質(zhì)量服務(wù)或減輕你可以參考外部電源提供優(yōu)質(zhì)服務(wù)。</p><p><b>　　其他資源</b></p><p>　　電氣與電子工程師協(xié)會(huì)（IEEE），標(biāo)準(zhǔn)519-1992，“電機(jī)及電子學(xué)工程師聯(lián)合會(huì)建議措施和控制要求諧波在電力系統(tǒng)”（1992年），在www.ieee.org可用。</p><p>　　諧波和對(duì)稱分量之間的關(guān)系</p>

90、;<p>　　摘要 ：了新的術(shù)語(yǔ)，明確了對(duì)稱與諧波成分的關(guān)系。三相對(duì)稱集和不對(duì)稱集集合的分類(lèi)。子介紹，名稱分別為對(duì)稱平衡臺(tái)，套對(duì)稱不平衡，不對(duì)稱平衡集和不平衡不對(duì)稱套表明，三相集可以解決的任何一個(gè)，兩個(gè)或三個(gè)對(duì)稱組件集。從四個(gè)案例研究的結(jié)果表明，這些子類(lèi)和他們的解釋的對(duì)稱分量有助于理解有諧波分析的系統(tǒng)平衡和不平衡諧波源和負(fù)載。</p><p>　　關(guān)鍵字：非對(duì)稱集;諧波流動(dòng);諧波源;對(duì)稱分量套;對(duì)稱

91、套。</p><p>　　任何周期波的形狀可以分解成或作為基波和諧波一系列的分析。</p><p>　　三相諧波分析，需要對(duì)諧波源之間，對(duì)稱分量輸入關(guān)系有清楚的了解（如調(diào)速，ASD負(fù)載）及其關(guān)系（對(duì)稱分量）從一個(gè)諧波源應(yīng)用程序所產(chǎn)生的線性系統(tǒng)諧波流動(dòng)。</p><p>　　引用數(shù)量有限的簡(jiǎn)要信息包含關(guān)于諧波及對(duì)稱分量。參考文獻(xiàn)1，提供了關(guān)于這一主題的段落，并使用與諧

92、波及標(biāo)題'關(guān)系對(duì)稱分量'。它包括一個(gè)由一個(gè)簡(jiǎn)短的解釋性段落，支持表。表中的術(shù)語(yǔ)表達(dá)了積極的諧波，負(fù)，零序列。這些序列在平衡的三相系統(tǒng)諧波。指的標(biāo)題，而對(duì)稱的部分內(nèi)容是指平衡三相系統(tǒng)。這就是異常。從本質(zhì)上講，（特別是埃羅序列）對(duì)稱分量只適用于非平衡系統(tǒng)。下面的問(wèn)題閱讀一段后參考。</p><p>　　是否對(duì)稱分量（特別是零序）在傳統(tǒng)意義上，適用于均衡和不平衡非正弦系統(tǒng)，這是從打破傳統(tǒng)？</p&

93、gt;<p>　　什么條件，對(duì)稱，非對(duì)稱，平衡，非平衡和對(duì)稱的部件是什么意思？</p><p>　　什么條件下運(yùn)作的系統(tǒng)以便諧解決正序 負(fù)序，零序列，并給出了參考表。 1，正確嗎？</p><p>　　所使用的術(shù)語(yǔ)描述，發(fā)現(xiàn)非正弦系統(tǒng)的不足。因此，有必要制定三階段的術(shù)語(yǔ)，將顯示的關(guān)系，并與輸入（電流）和諧波流動(dòng)（電壓和電流）有意義的比較。</p><p&g

94、t;　　參考資料3提供了提供'定義為解決方案的基礎(chǔ)'三相套，'對(duì)稱設(shè)置'和'對(duì)稱分量集'。</p><p>　　本文件的目的是引入到諧波分析的三相集分類(lèi)的方法，并要通過(guò)表達(dá)的對(duì)稱分量套數(shù)量的結(jié)果，輸入之間的比較，從諧波源和相應(yīng)的量化的諧波流動(dòng)創(chuàng)立。</p><p>　　諧波流動(dòng)及其決議對(duì)稱分量取決于程度及注射相序列，從諧波源，對(duì)系統(tǒng)的序列阻抗

95、，在三分線和四線連接的用戶是否對(duì)系統(tǒng)非線性負(fù)載平衡或不平衡。因此，什么是在對(duì)稱分量集合的輸入一諧波源不一定是收到系統(tǒng)，即諧波流入可能會(huì)解決一，兩個(gè)或三個(gè)對(duì)稱套，這取決于三個(gè)類(lèi)型相集發(fā)現(xiàn)。因此，任何三相諧波可能部分組成對(duì)稱分量的任何一組。</p><p>　　四個(gè)案研究報(bào)告，他們顯示出對(duì)教學(xué)的電力系統(tǒng)諧波流量的新方法。重要的是，作為一個(gè)人的教學(xué)案例研究的一部分，他們的聯(lián)系學(xué)習(xí)觀念，提高認(rèn)識(shí)。它們表明如何對(duì)稱分量的方