電氣專業(yè)外文翻譯3

1、<p>　　1 Power Quality Monitoring</p><p>　　Patrick Coleman</p><p>　　Many power quality problems are caused by inadequate wiring or improper grounding. These problems can be detected by simpl

2、e examination of the wiring and grounding systems. Another large population of power quality problems can be solved by spotchecks of voltage, current, or harmonics using hand held meters. Some problems, however, are inte

3、rmittent and require longer-term monitoring for solution.</p><p>　　Long-term power quality monitoring is largely a problem of data management. If an RMS value of voltage and current is recorded each electric

4、al cycle, for a three-phase system, about 6 gigabytes of data will be produced each day. Some equipment is disrupted by changes in the voltage waveshape that may not affect the rms value of the waveform. Recording the vo

5、ltage and current waveforms will result in about 132 gigabytes of data per day. While modern data storage technologies may make it feasible </p><p>　　Most commercially available power quality monitoring equi

6、pment attempts to reduce the recorded data to manageable levels. Each manufacturer has a generally proprietary data reduction algorithm. It is critical that the user understand the algorithm used in order to properly int

7、erpret the results.</p><p>　　1.1 Selecting a Monitoring Point</p><p>　　Power quality monitoring is usually done to either solve an existing power quality problem, or to determine the electrical

8、environment prior to installing new sensitive equipment. For new equipment, it is easy to argue that the monitoring equipment should be installed at the point nearest the point of connection of the new equipment. For pow

9、er quality problems affecting existing equipment, there is frequently pressure to determine if the problem is being caused by some external source, i.e., the</p><p>　　1.1.1 What to Monitor</p><p&g

10、t;　　At minimum, the input voltage to the affected equipment should be monitored. If the equipment is single phase, the monitored voltage should include at least the line-to-neutral voltage and the neutral to-ground volta

11、ges. If possible, the line-to-ground voltage should also be monitored. For three-phase equipment, the voltages may either be monitored line to neutral, or line to line. Line-to-neutral voltages</p><p>　　are

12、easier to understand, but most three-phase equipment operates on line-to-line voltages. Usually, it is preferable to monitor the voltage line to line for three-phase equipment.</p><p>　　If the monitoring equ

13、ipment has voltage thresholds which can be adjusted, the thresholds should be set to match the sensitive equipment voltage requirements. If the requirements are not known, a good starting point is usually the nominal equ

14、ipment voltage plus or minus 10%.</p><p>　　In most sensitive equipment, the connection to the source is a rectifier, and the critical voltages are DC. In some cases, it may be necessary to monitor the critic

15、al DC voltages. Some commercial power quality monitors are capable of monitoring AC and DC simultaneously, while others are AC only.</p><p>　　It is frequently useful to monitor current as well as voltage. Fo

16、r example, if the problem is being caused by voltage sags, the reaction of the current during the sag can help determine the source of the sag. If the current doubles when the voltage sags 10%, then the cause of the sag

17、is on the load side of the current monitor point. If the current increases or decreases 10–20% during a 10% voltage sag, then the cause of the sag is on the source side of the current monitoring point.</p><p&g

18、t;　　Sensitive equipment can also be affected by other environmental factors such as temperature, humidity, static, harmonics, magnetic fields, radio frequency interference (RFI), and operator error or sabotage. Some comm

19、ercial monitors can record some of these factors, but it may be necessary to install more than one monitor to cover every possible source of disturbance.</p><p>　　It can also be useful to record power quanti

20、ty data while searching for power quality problems. For example, the author found a shortcut to the source of a disturbance affecting a wide area by using the power quantity data. The recordings revealed an increase in d

21、emand of 2500 KW immediately after the disturbance. Asking a few questions quickly led to a nearby plant with a 2500 KW switched load that was found to be malfunctioning.</p><p>　　1.2 Selecting a Monitor<

22、/p><p>　　Commercially available monitors fall into two basic categories: line disturbance analyzers and voltage recorders. The line between the categories is becoming blurred as new models are developed. Voltag

23、e recorders are primarily designed to record voltage and current strip chart data, but some models are able to capture waveforms under certain circumstances. Line disturbance analyzers are designed to capture voltage eve

24、nts that may affect sensitive equipment. Generally, line disturbance analyzers </p><p>　　In order to select the best monitor for the job, it is necessary to have an idea of the type of disturbance to be reco

25、rded, and an idea of the operating characteristics of the available disturbance analyzers. For example, a common power quality problem is nuisance tripping of variable speed drives. Variable speed drives may trip due to

26、the waveform disturbance created by power factor correction capacitor switching, or due to high or low steady state voltage, or, in some cases, due to excessive v</p><p>　　To select the best monitor for the

27、job, it is necessary to understand the characteristics of the available monitors. The following sections will discuss the various types of data that may be needed for a power quality investigation, and the characteristic

28、s of some commercially available monitors.</p><p>　　1.3 Voltage</p><p>　　The most commonly recorded parameter in power quality investigations is the RMS voltage delivered to the equipment. Manuf

29、acturers of recording equipment use a variety of techniques to reduce the volume of the data recorded. The most common method of data reduction is to record Min/Max/Average data over some interval. Figure 1.1 shows a str

30、ip chart of rms voltages recorded on a cycle-by-cycle basis. Figure 1.2 shows a Min/Max/Average chart for the same time period. A common recording period is 1 </p><p>　　FIGURE 1.1 RMS voltage strip chart, ta

31、ken cycle by cycle.</p><p>　　FIGURE 1.2 Min/Max/Average strip chart, showing the minimum single cycle voltage, the maximum single cycle voltage, and the average of every cycle in a recording interval. Compar

32、e to the Fig. 1.1 strip chart data. </p><p>　　Some line disturbance analyzers allow the user to set thresholds for voltage events. If the voltage exceeds these thresholds, a short duration strip chart is cap

33、tured showing the voltage profile during the event. This short duration strip chart is in addition to the long duration recordings, meaning that the engineer must look at several different charts to find the needed infor

34、mation.</p><p>　　Some voltage recorders have user-programmable thresholds, and record deviations at a higher resolution than voltages that fall within the thresholds. These deviations are incorporated into t

35、he stripchart, so the user need only open the stripchart to determine, at a glance, if there are any significant events. If there are events to be examined, the engineer can immediately “zoom in” on the portion of the st

36、ripchart with the event.</p><p>　　Some voltage recorders do not have user-settable thresholds, but rather choose to capture events based either on fixed default thresholds or on some type of significant chan

37、ge. For some users, fixed thresholds are an advantage, while others are uncomfortable with the lack of control over the meter function. In units with fixed thresholds, if the environment is normally somewhat disturbed, s

38、uch as on a welder circuit at a motor control center, the meter memory may fill up with insignificant event</p><p>　　FIGURE 1.3 Cycle-by-cycle rms strip chart showing two voltage sags. The sag on the left is

39、 due to an adjacent feeder fault on the supply substation, and the sag on the right is due to a large motor start. Note the difference in the voltage profile during recovery</p><p>　　FIGURE 1.4 Min/Max/Avera

40、ge strip chart of the same voltage sags as Fig. 1.3. Note that both sags look almost identical. Without the recovery detail found in Fig. 1.3, it is difficult to determine a cause for the voltage sags</p><p>

41、;　　FIGURE 1.5 Typical voltage waveform disturbance caused by power factor correction capacitor energization</p><p>　　1.3.1 Voltage Waveform Disturbances.</p><p>　　Some equipment can be disturbed

42、 by changes in the voltage waveform. These waveform changes may not significantly affect the rms voltage, yet may still cause equipment to malfunction. An rms-only recorder may not detect the cause of the malfunction. Mo

43、st line disturbance analyzers have some mechanism to detect and record changes in voltage waveforms. Some machines compare portions of successive waveforms, and capture the waveform if there is a significant deviation in

44、 any portion of the waveform.</p><p>　　The most common voltage waveform change that may cause equipment malfunction is the disturbance created by power factor correction capacitor switching. When capacitors

45、are energized, a disturbance is created that lasts about 1 cycle, but does not result in a significant change in the rms voltage. Figure 1.5 shows a typical power factor correction capacitor switching event.</p>&

46、lt;p>　　FIGURE 1.6 RMS stripcharts of voltage and current during a large current increase due to a motor start downstream of the monitor point.</p><p>　　1.4 Current Waveshape Disturbances</p><p&

47、gt;　　Very few monitors are capable of capturing changes in current waveshape. It is usually not necessary to capture changes in current waveshape, but in some special cases this can be useful data. For example,inrush cur

48、rent waveforms can provide more useful information than inrush current rms data. Figure 1.7 shows a significant change in the current waveform when the current changes from zero to nearly 100 amps peak. The shape of the

49、waveform, and the phase shift with respect to the voltage wavefor</p><p>　　Figure 1.7 shows the first few cycles of the event shown in Fig.1.6.</p><p>　　1.5 Harmonics</p><p>　　Harmo

50、nic distortion is a growing area of concern. Many commercially available monitors are capable of capturing harmonic snapshots. Some monitors have the ability to capture harmonic strip chart data. In this area, it is crit

51、ical that the monitor produce accurate data. Some commercially available monitors have deficiencies in measuring harmonics. Monitors generally capture a sample of the voltage and current waveforms, and perform a Fast Fou

52、rier Transform to produce a harmonic spectrum. Accordin</p><p>　　1.6 Summary</p><p>　　Most power quality problems can be solved with simple hand-tools and attention to detail. Some problems, how

53、ever, are not so easily identified, and it may be necessary to monitor to correctly identify the problem. Successful monitoring involves several steps. First, determine if it is really necessary to monitor. Second, decid

54、e on a location for the monitor. Generally, the monitor should be installed close to the affected equipment. Third, decide what quantities need to be monitored, such as vol</p><p>　　Usually, a good first cho

55、ice is at least one business cycle, or at least 1 day, and more commonly, 1 week. It may be necessary to monitor until the problem recurs. Some monitors can record indefinitely by discarding older data to make space for

56、new data. These monitors can be installed and left until the problem recurs. When the problem recurs, the monitoring should be stopped before the event data is discarded.</p><p>　　After the monitoring period

57、 ends, the most difficult task begins — interpreting the data. Modern power quality monitors produce reams of data during a disturbance. Data interpretation is largely a matter of experience, and Ohm’s law. There are man

58、y examples of disturbance data in books such as The BMI Handbook of Power Signatures, Second Edition, and the Dranetz Field Handbook for Power Quality Analysis.</p><p><b>　　1 電能質(zhì)量監(jiān)測 </b></p>

59、;<p><b>　　帕特里克·科爾曼</b></p><p>　　許多電能質(zhì)量問題所造成的布線不足或不當(dāng)?shù)慕拥?。這些問題可以由簡單的檢查接線和接地系統(tǒng)的檢測。另一個人口眾多的電能質(zhì)量問題是可以解決的抽查，電壓，電流或諧波使用手持米。然而，一些問題，間歇性和需要長期監(jiān)測解決方案。</p><p>　　長期的電能質(zhì)量監(jiān)測主要是數(shù)據(jù)管理中存在的問題

60、。如果電壓的RMS值和當(dāng)前記錄每個電周期為三相系統(tǒng)，將每天生產(chǎn)約6個字節(jié)的數(shù)據(jù)。一些設(shè)備被破壞的電壓波形的變化，可能不會影響波形的RMS值。記錄電壓和電流波形將導(dǎo)致約132千兆字節(jié)數(shù)據(jù)的每一天。雖然現(xiàn)代數(shù)據(jù)存儲技術(shù)是可行的，記錄每一個電周期，在這個數(shù)據(jù)的質(zhì)量檢測電能質(zhì)量問題的任務(wù)確實是艱巨的。</p><p>　　大部分市售的電能質(zhì)量監(jiān)測設(shè)備，試圖減少記錄的數(shù)據(jù)管理的水平。每個制造商有一個普遍的專有的數(shù)據(jù)縮減算法

61、。關(guān)鍵是了解用戶所使用的算法，以便正確地解釋結(jié)果。</p><p>　　1.1 選擇一個監(jiān)測點</p><p>　　電能質(zhì)量監(jiān)測通常是可以解決現(xiàn)有的電能質(zhì)量問題，或事先確定的電氣環(huán)境，安裝新的敏感設(shè)備。對于新的設(shè)備，很容易認(rèn)為監(jiān)控設(shè)備應(yīng)在安裝新設(shè)備的連接點最近的點。影響現(xiàn)有設(shè)備的電能質(zhì)量問題，頻頻施壓，以確定如果問題正在引起一些外部來源，即實用。這導(dǎo)致監(jiān)測設(shè)備的安裝服務(wù)點嘗試檢測問題的根源

62、。這通常是沒有監(jiān)測設(shè)備的最佳位置。大多數(shù)研究表明，電能質(zhì)量問題， 80 ％來自設(shè)施內(nèi)。受影響的設(shè)備上安裝一個監(jiān)視器將檢測設(shè)施內(nèi)的問題，以及存在的問題，在始發(fā)實用工具。每種類型的事件已顯著特點，以協(xié)助工程師正確識別干擾源。</p><p><b>　　1.1.1 監(jiān)測</b></p><p>　　至少，向受影響的設(shè)備的輸入電壓進(jìn)行監(jiān)測。如果設(shè)備是單相，監(jiān)視電壓應(yīng)包括至少

63、線到中性點電壓和中性的對地電壓。如果可能的話，線對地電壓也應(yīng)監(jiān)測。對于三相設(shè)備，電壓可能被監(jiān)視線中性，或線到線。線到中性的電壓更容易理解，但最三相設(shè)備上線到線電壓運作。通常情況下，最好是監(jiān)視線到線電壓為三相設(shè)備。</p><p>　　如果監(jiān)控設(shè)備有可調(diào)節(jié)的電壓閾值，閾值應(yīng)設(shè)置相匹配的敏感設(shè)備的電壓要求。如果要求不知道，一個很好的起點通常是設(shè)備的額定電壓加上或減去10％ 。</p><p>

64、　　在最敏感的設(shè)備，連接到源是一個整流器，臨界電壓是直流。在某些情況下，它可能是必要的監(jiān)控關(guān)鍵的直流電壓。一些商業(yè)的電能質(zhì)量監(jiān)測儀能夠監(jiān)測交流和直流同時，而另一些則僅交流。</p><p>　　它常常是有用的監(jiān)測電流以及電壓。例如，如果問題正在引起電壓驟降，目前在凹陷的反應(yīng)，可以幫助確定凹陷源。如果目前的雙打時的電壓驟降10％ ，那么下垂的原因是負(fù)載側(cè)電流監(jiān)測點。如果電流增加或減少10-20％ ， 10％的電壓驟

65、降期間，凹陷的原因是對源端的電流監(jiān)測點。</p><p>　　敏感的設(shè)備，也可以受到其他環(huán)境因素，如溫度，濕度，靜態(tài)，諧波磁場，無線電頻率干擾（RFI） ，操作錯誤或破壞。一些商業(yè)顯示器，可以記錄一些這些因素，但它可能需要安裝多臺監(jiān)視器，以涵蓋所有可能的干擾源。</p><p>　　它也可以是有用的發(fā)電量數(shù)據(jù)，同時記錄電能質(zhì)量問題。例如，筆者發(fā)現(xiàn)一個快捷方式的影響發(fā)電量數(shù)據(jù)采用大面積的干擾

66、源。錄音顯示，增加2500千瓦的需求后，立即干擾。要求迅速導(dǎo)致附近一個2500千瓦的電廠的幾個問題，發(fā)現(xiàn)故障切換負(fù)載。</p><p><b>　　1.2 選擇顯示器</b></p><p>　　市售顯示器分為兩個基本類別：線干擾分析儀和電壓記錄。類別之間的界線變得模糊，作為新車型的開發(fā)。電壓記錄儀主要是用來記錄電壓和電流的帶狀圖數(shù)據(jù)，但一些模型能夠捕捉到在某些情況下

67、的波形。線干擾分析儀是用來捕捉電壓事件可能會影響敏感設(shè)備。一般來說，行干擾分析儀是沒有良好的電壓錄像機(jī)，但新的模式比以往的設(shè)計在錄音電壓帶圖表。</p><p>　　為了選擇最好的顯示器工作，這是必要的干擾類型有一個想法，要記錄，并提供干擾分析儀的經(jīng)營特色的想法。例如，一個共同的電能質(zhì)量問題是跳閘滋擾變速驅(qū)動器。變速驅(qū)動器的行程由于功率因數(shù)校正電容切換，或高或低的穩(wěn)態(tài)電壓，由于創(chuàng)建的波形干擾，或在某些情況下，由于

68、過度的電壓不平衡。如果驅(qū)動器的行程，由于高電壓或波形干擾，驅(qū)動器的診斷通常會顯示過電壓跳閘原因代碼。如果電壓不均衡，驅(qū)動器將提請顯著的不平衡電流。目前的不平衡可能達(dá)到的水平，導(dǎo)致過電流的驅(qū)動器輸入的行程。選擇變速驅(qū)動器跳閘的顯示器可以是一個挑戰(zhàn)。最線干擾分析儀可以輕松地捕獲波形干擾電容器切換，但他們沒有良好的電壓錄像機(jī)，可能不會做報告穩(wěn)態(tài)高電壓做好。許多線干擾分析儀無法捕捉所有的電壓不平衡，也不會對他們應(yīng)對當(dāng)前的事件，除非有一個相應(yīng)的電

69、壓事件。大多數(shù)的電壓和電流的錄像機(jī)可以輕松地捕獲穩(wěn)態(tài)高電壓驅(qū)動器跳閘，導(dǎo)致，但他們可能無法捕捉到的電容開關(guān)波形干擾。許多電壓錄像機(jī)可以捕捉電壓不平衡，電流不平衡，其中一些將觸發(fā)捕獲的電壓和電流在當(dāng)前的事件，如關(guān)閉驅(qū)動器跳閘。</p><p>　　要選擇這個職位的最佳顯示器，它是必要的，以了解可用的顯示器的特點。以下各節(jié)將討論的各類電能質(zhì)量調(diào)查，和一些市售顯示器的特點，可為需要的數(shù)據(jù)。</p><

70、;p><b>　　1.3 電壓</b></p><p>　　電能質(zhì)量調(diào)查記錄最常用的參數(shù)是RMS電壓傳遞到設(shè)備。錄音設(shè)備的制造商使用了多種技術(shù)，以減少記錄的數(shù)據(jù)量。最常用的方法是減少的數(shù)據(jù)記錄超過一定間隔的最小/最大/平均數(shù)據(jù)。圖1.1顯示了一個循環(huán)周期的基礎(chǔ)上記錄的RMS電壓的條狀圖。圖1.2顯示了一個最小/最大/同一時期的平均圖表。一個常見的記錄期限為1個星期。典型的錄像機(jī)使用的記

71、錄間隔2-5分鐘。每個記錄間隔會產(chǎn)生三個數(shù)字：最高的1個周期，最低的1個周期，每個周期的時間間隔內(nèi)的平均電壓有效值。這是一個簡單，容易理解的記錄方法，并很容易實現(xiàn)由生產(chǎn)商。這種方法有幾個缺點。如果有幾個事件記錄間隔期間，只有最大偏差的事件被記錄下來。除非記錄儀的記錄的事件在一些其他的方式，有沒有時間戳記與事件有關(guān)，并沒有可用的時間。最關(guān)鍵的缺陷是缺乏活動期間的電壓檔。電壓檔事件源提供了重要的線索。例如，如果該事件是一個電壓驟降，最低的電

72、壓可能是相同的一個遙遠(yuǎn)的公用工程系統(tǒng)故障引起的事件，并為附近的一個大型電機(jī)啟動。然而，對于遙遠(yuǎn)的故障，電壓將下垂幾乎瞬間，留在3-10個周期相對穩(wěn)定的水平，幾乎立即恢復(fù)到全電壓，也可能是稍高的電壓如果公用系統(tǒng)故障的部分分離。附近的電</p><p>　　圖1.1電壓有效值帶狀圖，采取循環(huán)周期</p><p>　　圖1.2最小/最大/平均帶圖表，顯示單周期的最低電壓，最大的單周期電壓，平均每

73、個記錄間隔周期。比較的圖。 1.1帶狀圖數(shù)據(jù)</p><p>　　一些線路干擾分析儀允許用戶設(shè)置閾值電壓事件。如果電壓超過這些閾值，持續(xù)時間短條狀圖表顯示電壓檔在事件捕獲。在這短短的時間帶圖表除了持續(xù)時間長的錄音，這意味著工程師必須在幾個不同的圖表看，找到所需要的信息。</p><p>　　一些電壓錄像機(jī)有用戶可編程的閾值，并記錄偏差，在更高的分辨率比內(nèi)閾值的電壓。這些偏差納入帶狀圖，使用

74、戶只需要打開帶圖表來確定，一目了然，如果有任何重大的事件。如果有被檢查的事件，工程師可以立即帶狀圖的一部分，與事件“放大” 。</p><p>　　一些電壓錄像機(jī)不具備用戶設(shè)定的閾值，而是選擇捕捉固定的默認(rèn)閾值或某些類型的顯著變化的事件。對于某些用戶，固定閾值的優(yōu)勢，而另一些不舒服，缺乏控制儀表功能。與固定閾值的單位，如果通常是有點不安的環(huán)境，如在電機(jī)控制中心的焊工電路，儀表內(nèi)存可能填補(bǔ)了微不足道的事件和顯示器可

75、能無法記錄一個重要的事件發(fā)生時。出于這個原因，不應(yīng)該被用來固定閾值的顯示器，在電氣噪聲環(huán)境。</p><p>　　圖1.3逐周期有效值帶狀圖顯示兩個電壓驟降。左側(cè)凹陷是由于供應(yīng)變電站相鄰饋線故障，右側(cè)的凹陷是由于大電機(jī)啟動。注意在恢復(fù)過程中的電壓檔的差異</p><p>　　圖1.4最小/最大/平均帶狀圖如圖相同的電壓驟降。 1.3。請注意，這兩個凹陷看起來幾乎相同。如果沒有恢復(fù)細(xì)節(jié)圖。

76、1.3 ，這是難以確定的電壓驟降的一個原因</p><p>　　圖1.5典型電壓波形的功率因數(shù)校正電容器通電造成的干擾</p><p>　　1.3.1 電壓波形干擾</p><p>　　一些設(shè)備可以干擾電壓波形的變化。這些波形的變化可能不會顯著影響的rms電壓，但仍可能導(dǎo)致設(shè)備故障。只有一個RMS錄音機(jī)可能無法檢測到的故障原因。大多數(shù)線干擾分析儀有某種機(jī)制來檢測和記

77、錄電壓波形的變化。有些機(jī)器比較連續(xù)波形的部分，并捕獲波形的波形的任何部分，如果有一個顯著偏離。其他捕獲的波形在連續(xù)波形的有效值，如果有一個顯著的變化。另一種方法是捕捉波形電壓總諧波失真（THD），連續(xù)循環(huán)之間，如果有一個顯著的變化。</p><p>　　最常見的電壓波形的變化可能導(dǎo)致設(shè)備故障是由功率因數(shù)校正電容器切換干擾。當(dāng)通電時，電容干擾創(chuàng)建，持續(xù)約1個周期，但不會導(dǎo)致電壓有效值的一個顯著的變化。圖1.5顯示了

78、一個典型的功率因數(shù)校正電容切換事件。</p><p>　　圖1.6 RMS的條狀圖表的電壓和大電流的增加，由于下游電機(jī)啟動時電流 監(jiān)測點</p><p>　　1.4 電流波形擾動</p><p>　　極少數(shù)顯示器能夠捕獲電流波形的變化。捕捉電流波形的變化，它通常是沒有必要的，但在某些特殊情況下，這可能是有用的數(shù)據(jù)。例如，浪涌電流波形可以提供更多有用的信息比浪涌電流有

79、效值數(shù)據(jù)。圖1.7顯示了顯著的變化時，在電流波形從零到近100安培的峰值電流的變化。波形和電壓波形相移的形狀，確認(rèn)該電流的增加是由于感應(yīng)電機(jī)啟動。圖1.7顯示在圖1.6所示的事件前幾個周期。</p><p>　　圖1.7電壓和電流波形在圖1.6所示的電流增加的前幾個周期</p><p><b>　　1.5 諧波</b></p><p>　　諧波

80、失真是一個令人關(guān)注的種植面積。許多市售的顯示器能夠捕獲諧波快照。有些顯示器有能力捕捉諧波條狀圖表數(shù)據(jù)。在這方面，關(guān)鍵是顯示器生產(chǎn)準(zhǔn)確的數(shù)據(jù)。一些市售的顯示器具有測量諧波的缺陷。顯示器一般捕獲的電壓和電流波形樣本，并進(jìn)行快速傅立葉變換產(chǎn)生的諧波頻譜。根據(jù)奈奎斯特采樣定理，必須輸入波形采樣至少兩次的頻率最高，是目前在波形。一些制造商解釋這意味著感興趣的最高頻率，并相應(yīng)地調(diào)整其采樣率。如果輸入信號中包含以上的最高頻率可以正確采樣頻率，高頻信號

81、可能會被“別名” ，也就是說，它可能會被錯誤地認(rèn)定為一個較低的頻率諧波。這可能導(dǎo)致工程師尋找一個不存在的諧波問題的解決方案。通過采樣混疊問題可以得到緩解，在更高的采樣率，并篩選出感興趣的最高頻率以上的頻率。采樣率通常被發(fā)現(xiàn)在制造商的文學(xué)，但存在一個抗混疊濾波器通常不是在文獻(xiàn)中提到的。</p><p><b>　　1.6總結(jié)</b></p><p>　　大部分的電能質(zhì)量

82、問題可以解決簡單的手工工具和注意細(xì)節(jié)。然而，有些問題，不是那么容易確定，它可能是必要的監(jiān)測，正確識別的問題。成功地監(jiān)測涉及幾個步驟。首先，確定如果真的是必要的監(jiān)控。第二，決定了顯示器的位置。一般而言，顯示器的受影響的設(shè)備應(yīng)安裝在靠近。第三，決定需要進(jìn)行監(jiān)測，如電壓，電流，諧波，功率數(shù)據(jù)，什么數(shù)量。嘗試，以確定事件的類型，可以干擾設(shè)備，并選擇一米，是能夠檢測這些類型的事件。四，決定上一個監(jiān)測期。通常，一個良好的第一選擇是至少一個營業(yè)周期，

83、或至少1天，而更常見的， 1個星期。這可能是必要的監(jiān)督，直到問題再次出現(xiàn)。有些顯示器可以無限期地丟棄舊的數(shù)據(jù)記錄，使新的數(shù)據(jù)空間。這些監(jiān)視器可以安裝和離開，直到問題再次出現(xiàn)。當(dāng)問題再次出現(xiàn)，監(jiān)控事件數(shù)據(jù)將被丟棄之前，應(yīng)該停止。</p><p>　　監(jiān)測期結(jié)束后，最艱巨的任務(wù)開始 - 解釋數(shù)據(jù)?，F(xiàn)代電能質(zhì)量監(jiān)測過程中產(chǎn)生大量的數(shù)據(jù)擾動。數(shù)據(jù)的解釋主要是一個經(jīng)驗的問題，歐姆定律。有許多書籍，如BMI電力簽名手冊（第二