電氣自動化專業(yè)外文翻譯

1、畢業(yè)設(shè)計(論文)外文資料翻譯題 目: 使用小波變換在中性非有效接地的分配系統(tǒng)中識別單相接地故障饋線 附 件： 1.外文資料翻譯譯文；2.外文原文。 使用小波變換在中性非有效接地的分配系統(tǒng)中識別單相接地故障饋線 abstracta scheme of single-phase-to-ground fault feede摘要：本文介紹小波變換技術(shù)的在配電網(wǎng)單相接地故障饋線識別的一種應(yīng)用方案。該計劃使用零序當(dāng)前行波識別的故障饋線和母線的殘余電壓，以確定故障或開關(guān)操作引起的事件thescheme uses zero-sequence current traveling waves to identfa

2、ulted feeder, and the busbar residual voltage to determievent caused by fault or 。the current travelin由零序電流傳感器測量當(dāng)前行波分解提出利用小波多分辨分析。the local modulus當(dāng)?shù)匦〔ㄗ儞Q的模的maxima of the wavelet transform are extracted to determine the極大值確定了time of the initial traveling wave.初始行波的時間。所有饋線上的小波變換在時間上相互比較大小和極性找出故障饋線the

3、wavelet transforms on all所有所有 。the feeder identification饋線標(biāo)識is independent of the network neutral-point grounding mode.獨立于電網(wǎng)中性點接地方式。the proposed scheme was implemented and verified using elec-tromagnetic transients program (emtp)-generated signals.擬議的計劃通過電磁暫態(tài)程式（emtp）已經(jīng)被實施和驗證。在正常情況下thescheme proved t

4、o be robust against transients generated during對如饋線充電和放電以及as capacitor bank switching.電容器組切換的瞬態(tài)響應(yīng)來說，這個計劃被證明是具有魯棒性的。關(guān)鍵詞：配電保護(hù) 、小波變換、殘壓、零序電流index termspower distribution protection, residual voltage,關(guān)鍵詞 看關(guān)鍵詞i. i ntroduction一、引言 帶有如不接地，高電阻接地，and neutralizer grounded, are often called the neutral nonef-f

5、ectively grounded distribution systems.和中性點接地的小接地故障電流的分布式系統(tǒng)distribution systems with low levels of ground-fault帶，通常被稱為的非有效中性點接地的分布系統(tǒng)。a distinguishing fea-ture of such systems is the ability to continue to operate the這種系統(tǒng)的特點是在單線接地的情況下能夠繼續(xù)運(yùn)行一段時間。since the system neu-tral is not solidly grounded, there

6、 is little current flow in the由于系統(tǒng)的中性點沒有完全接地，因此接地故障時電流很小，同時系統(tǒng)的工作狀態(tài)沒有達(dá)到非正常的電流水平。at the same在同一time, because of the very limited ground fault current, it is fre-quently considered impractical to try to provide ground-fault時間，因為在非常有限的接地故障電流，試圖用這個系統(tǒng)去保護(hù)接地故障通常被認(rèn)為是不切實際的。typically, the only relaying provide

7、d 通常情況下，該系統(tǒng)唯一提供的繼電保護(hù)是零序過電壓保護(hù)(with no indication of which feeder is faulted).（沒有指示是哪根饋線故障）。the alarm only僅報警indicates that a ground fault exists somewhere on the system.表示系統(tǒng)接地故障存在于某個地方。typical operating practice is to manually run tests to determine典型工作的做法是手動運(yùn)行測試確定the faulted feeder.故障饋線。 in the past

8、 decade many techniques 1 have been develop在過去的十年中，已經(jīng)開發(fā)出許多技術(shù)to improve the identification of faulted feeder in neutral non-effectively grounded distribution system.以提高非中性點有效接地分布式系統(tǒng)饋線故障的識別。they can be roughly他們大致可以divided into two groups: fundamental system frequency com-ponents based algorithms and

9、transient signal based algorithms.分為兩組：基于基本系統(tǒng)頻率元件算法和基于暫態(tài)信號算法。fundamental system frequency components based algorithms基本系統(tǒng)頻率元件的算法 such as magnitude comparison relay, phase comparison relay如幅度比較繼電器，相位比較繼電器， 瓦特計式wattmetric detection relay 2, 3瓦特 檢測繼電器 are not fully successful,沒有完全成功 ,either due to thei

10、r inability to identify faulted feeder with low由于他們無法確定在低電流下的故障饋線current or to their maloperation by the maximum load unbal-ance expected on the circuit. 另一方面線路上預(yù)期的最大不平衡負(fù)荷會引起他們的誤動作。in fact, the signals which would事實上，零序設(shè)備檢測的信號包含著顯著的暫態(tài)成分。 transients are generally much greater than瞬變一般遠(yuǎn)遠(yuǎn)大于the power fr

11、equency component.電源頻率分量。moreover, single phase fault此外，單相故障往往由連續(xù)的短時間瞬態(tài)自熄故障形成往往 。in the paper 4, pronys method i在文獻(xiàn)4，prony的方法是applied to earth fault current analysis in petersen-coil-protected在保護(hù)消弧線圈系統(tǒng)中應(yīng)用接地故障電流分析systems.。the papers 5, 6 use artificial neural networks文獻(xiàn)5 6利用人工神經(jīng)網(wǎng)絡(luò)在諧振接地配電系統(tǒng)中檢測單相接地故障。a

12、nother study 7 began to apply另一項研究7開始在諧振接地配電系統(tǒng)應(yīng)用wavelets to analyze transient earth fault signals in resonant小波分析暫態(tài)接地故障。papers 8, 9 present文獻(xiàn)8 9，提出single-phase-to-ground fault feeder selection based on wavelet基于小波變換模的極大值的單相接地故障饋線選擇transform modulus maxima.。the paper 10 uses transient文獻(xiàn)10 在所選擇的頻段采用瞬態(tài)

13、信號signals in the chosen frequency band to identify faulted feede以確定故障饋線。 in this paper, the idea of identifying faulted feeder by com-paring magnitude and polarity of wavelet coefficients, suggested 在本文中，通過比較小波系數(shù)的大小和極性確定故障饋線的想法，建議in 8 without deep practical verification is thoroughly studied. 8不深入的實

14、際驗證和研究。這里給出的對在正常產(chǎn)生的瞬變events such as feeder energizing and de-energizing as well as事件的擴(kuò)展計劃its extended scheme against transients generated during normal它給，如饋線通電和斷電功能，以及capacitor bank switching is presented here and the results of ex-tensive simulative testing with electromagnetic transients pro-gram

15、(emtp) signals are described.電容器組切換產(chǎn)生的瞬變和廣泛的電磁暫態(tài)程序（emtp）信號的模擬測試結(jié)果描述。 the following sections of the paper include general introduc-tion of the wavelet technique (section ii), basic principle of the本文以下各節(jié)包括小波技術(shù)（第二部分），目前的行波計劃和實施（第三部分）的故障饋線鑒定的基本原則（第四部分）以及采用emtp的產(chǎn)生的信號測試結(jié)果的總體介紹（第五部分）。關(guān)閉本文的conclusions and

16、references close this paper.結(jié)論和參考。 i二、 w avelet transform小波變換 the wavelet transform is a powerful tool in the analysis of 小波變換是一個功能強(qiáng)大的工具，由于它提取時間和能力frequency information from the transient signal 1116.暫態(tài)信號的頻率信息能力在分析transient phenomena because of its ability to extract time and短暫的現(xiàn)象中 11 - 16。對于一個給定的連續(xù)

17、小波變換（cwt）定義為母線signal with respect to a mother wavelet is母線小波信號fig圖 1. 1。 shape of the derivative function of cubic b-spline function. 三次b樣條函數(shù)的導(dǎo)函數(shù)的形狀。 (1) （1） where is the scale factor and is the translation factor. 其中a是比例因數(shù)和b是轉(zhuǎn)換因數(shù)。 in fact, the signal in engineering areas we should analyze is 事實上，我們

18、應(yīng)該分析的在工程領(lǐng)域的信號usually discrete sequence通常是離散序列。在wavelet transforms of discrete se-quence are based on multiresolution analysis, and we have 離散序列小波x（n）變換多分辨率分析的基礎(chǔ)上，我們有的j a nd k are integers, representing the scale factor and the 和k是整數(shù)，即比例因數(shù)和translation factor, respectively; is a discrete approx-imatio

19、n of at t he resolution ; is the discrete轉(zhuǎn)換轉(zhuǎn)換因數(shù)，是離散信號在x（n）的決議2j; 是離散detail signal (wavelet transform) at the resolution ; and細(xì)節(jié)信號（小波變換）的決議; 2jare coefficients and they are determined only by the是系數(shù)，gk僅由他們確定mother wavelet.母小波。 (2) （2） there are many types of mother wavelets, such as harr and 母小波的種類有很

20、多，如哈爾和多貝西daubichies wavelets.多小波。the choice of mother wavelet plays a sig-ni ficant role in detecting and localizing different types of fault母小波的選擇在不同類型的故障檢測和定位transients瞬變起到了重要的作用。in addition, the choice also depends on a particular ap-plication.此外，母小波的選擇還依賴于一個特定的應(yīng)用程序。because the derivative functio

21、n of the cubic b-spline由于三次b樣條函數(shù)function requires the least support in all of the polynomial spline功能要求至少支持在所有的多項式樣條functions and can obtain a good approximation similar to th，可以得到類似的一個很好的近似gauss function, a derivative of the cubic b-spline function was高斯函數(shù)的三次b樣條函數(shù)的導(dǎo)數(shù)selected as the base wavelet fun

22、ction for the present study.作為本研究的基本小波函數(shù)選擇。 the（function and its shape are as (3) and shown in fig.3）如下它的形狀和系數(shù)。 1, respectively, (3) （3） for the aforementioned wavelets, the coef ficients are 對于上述小波，它的系數(shù)是 in order to obtain the characteristics of abrupt signal simply 為了獲得突變信號的特征，只需and clearly, the m

23、odulus maxima of wavelet transforms is in-troduced.并明確小波變換的模的極大值。they are de fined as the local maxima of the wavelet 他們被定義為本地的小波變換模的極大值，當(dāng)且僅當(dāng)滿足以下條件， 15, 17: 15，17： (4) （4） it has been verified that any signal could be reconstructed by 它已被證實的信號可重構(gòu)its modulus maxima 17, so the modulus maxima of wavele

24、t其模的極大值17，因此小波轉(zhuǎn)換模的極大值transforms contains all the useful information of the original包含了原有的所有有用的信息signal, and the modulus maxima of wavelet transforms can fully信號，小波變換模的極大值可以充分represent the original signal, including the signal s waveform,代表原始信號，包括信號的波形，properties, and slope of the variations.屬性和坡度的變化

25、。therefore, the modulus因此，在本中利用小波變換模得極大值數(shù)來了實施這個計劃。maxima of wavelet transforms is used in the paper to implement iii.三、 基本原理b asicprinciple基when a single-phase-to-ground fault occurs in one feeder, 當(dāng)單相接地故障發(fā)生在一個饋線是，產(chǎn)生的fault generated traveling waves will propagate from fault point故障行波點將從故障點沿饋線傳播到alon

26、g the feeder to the system.系統(tǒng)。 arriving at the point where wave到達(dá)行波impedance changes, for example, busbar in the substation, the阻抗的變化的，例如，母線變電站，traveling wave will be re flected and refracted.行波將反射和折射。 at the instant在當(dāng)前行波抵達(dá)瞬間when current traveling waves arrived at the point, they satisfy時，他們滿足kirchh

27、off s current law基爾霍夫電流定律 (5) （5） where n is the number of branches connected to the point, and 其中n是連接點的分行數(shù)目，ikis the current through number k branch.是通過k個分支電流。that is, the current in flow to the point is equal to the current也就是說，當(dāng)前電流在流入是等于電流的outflow.流出。as far as the busbar is concerned, the current

28、 value in至于有關(guān)母線， faulted feeder is equal to the sum of current in healthy feeders故障饋線電流值等于正常的饋線電流母線連接的總和connected to the busbar.。suppose the current reference direc-tion is de fined as from the busbar to the feeder, the currents in假設(shè)當(dāng)前的參考方向是從母線到饋線，在all healthy feeders have the same direction.所有健康的饋線

29、電流有相同的方向。 therefore current因此目前traveling wave of faulted feeder is reverse to, and much higher故障饋線電流的反向， than the wave of any healthy feeder, which is the basic principle比任何健康饋線的電流要高得多，這是to identify single-phase-to-ground fault feeder in neutral nonef-fectively grounded distribution system 18.確定單相接地

30、故障饋線中性非有效接地的配電系統(tǒng)基本原則18。 iv.四、proposed scheme 建議計劃 because current traveling waves generated during normal 因為在正常事件中，如饋線通電以及電容器組切換產(chǎn)生的行波會導(dǎo)致繼電器故障饋線誤懂，母線殘壓引入計劃to determine a disturbance as a fault or not.以確定故障或沒用的干擾。so the proposed因此，擬議scheme uses the busbar residual voltage to determine whether計劃使用母線的殘余

31、電壓，用來確定是否a phase-to-ground fault occurs, and zero-sequence current相接地故障時，零序電流traveling waves to identify which feeder is faulted.行波出現(xiàn)故障饋線。when a當(dāng)single-phase-to-ground fault occurs in one feeder, the residual單相接地故障發(fā)生在一個饋線中，殘余power frequency voltage in the busbar will rise to three times在母線電源頻率電壓將上升到

32、三倍the phase-to-phase voltage.相電壓。when a switch operates such as當(dāng)開關(guān)操作如feeder energizing, the residual power frequency voltage in the饋線充電，在剩余busbar is about zero.母線的工頻電壓是零。in the scheme, the busbar residual voltage在這項計劃中，母線的殘余電壓threshold is set as phase-to-phase voltage.閾值設(shè)置為相電壓。 fig. 圖 2. 2。 hardware

33、 arrangement of the proposed scheme. 該方案的硬件安排。 fig. 圖 3. 3。 flowchart of the proposed scheme. 擬議計劃的流程圖。 on the other hand the scheme uses initial traveling waves to 另一方面，該計劃使用初始行波來identify faulted feeder.確定故障饋線。the feeder length in distribution system在配電系統(tǒng)饋線長度is usually as short as several kilometer

34、s, even hundreds of me-ters, while the traveling wave speed can reach 300 .通常只要短短幾公里，甚至幾百米，而行波的速度可以達(dá)到300m/s。there-fore, to acquire the initial traveling waves correctly, high fre-quency sampling is necessary.因此，正確獲取初始行波，高頻率的采樣是必要的。and after analysis and compar-ison, the appropriate sampling rate is

35、selected as 1 mhz in the經(jīng)過分析和比較，選擇適當(dāng)?shù)牟蓸勇?兆赫在本文中paper.在。to meet different sampling frequency requirements, the為了滿足不同的采樣頻率的要求，scheme needs special design 19.計劃需要特殊的設(shè)計19。 hardware arrangements and 硬件安排和flowchart of the proposed scheme are shown in figs.擬議計劃的流程圖，在圖所示 2 and 3,2和3respectively. 分別。 the har

36、dware arrangement is mainly composed of three units: 硬件的安排主要是三個單位組成：電源頻率電壓處理單元power frequency voltage processing unit (pfu), current trav-eling waves processing unit (twu), and logic determination電源平（pfu），行波處理單元（twu）的和邏輯處理單元（ldu）。 在unit (ldu).在 in pfu, residual voltage from potential transformerpfu中

37、，殘余電壓電壓互感器(pt) is first transferred to 5 v voltage signals by v/v trans-former.（pt），首先通過v / v變壓器轉(zhuǎn)移到5 v的電壓信號，。then, 500 hz low pass filter is used to remove high fre-quency noise, and the signal is sampled at 1 khz and converted然后，500赫茲的低通濾波器用于去除高頻率的噪音，并在1 khz的采樣信號轉(zhuǎn)換to digital quantities.數(shù)字量。at last,

38、 cpu1 extracts the residual voltage最后，cpu1中提取的殘余電壓characteristics to determine whether the disturbance is fault or特性，以確定是否干擾故障或not沒有。 in twu, each feeder current from current transformers is first 在twu中，首先是每個饋線電流從電流互感器前通過i / v變壓器transferred to 5 v voltage signals by i/v transformers before高速采樣轉(zhuǎn)移至5 v

39、的電壓信號high-speed sampling.。then low-pass filters (lp) and band-pass然后低通濾波器（lp）和帶通filters (bp) are used to remove noise and generate triggering過濾器（bp）用于消除噪音并產(chǎn)生觸發(fā)signals for relay starting.為繼電器信號開始。the upper limit frequency for the lp上限頻率為lpfilters is set as 500 khz.過濾器設(shè)置為500千赫。the frequency band of th

40、e bp filtersbp濾波器的頻帶is selected as 3 10 khz, which ensures that the scheme starts被選定為3 10千赫，以確保該計劃開始reliably in most fault situations.可靠的大多數(shù)故障情況。 fault starting circuit compares 故障起動電路比較the signal output from bp filter with a certain threshold.從bp濾波器的輸出信號具有一定的閾值。when何時setting the threshold, it is ne

41、cessary to consider fault inception設(shè)置閾值，有必要考慮繼電器的靈敏度和可靠性。 in order to avoid frequent starting problem in nonfault situations, together 避免頻繁啟動問題非錯誤情況，連同with consideration of the practical situation, the threshold is考慮到實際情況，門檻set as 10% maximum value of the phase voltage in the paper.設(shè)置相電壓的最大值為10。in t

42、his case, faults, whose inception angle is greater than 6 ,在這種情況下，故障，其成立以來的角度大于6,could all be detected.都可以被檢測出來。the sampling/hold (s/h) circuit samples采樣/保持（s / h）電路樣品analog signals and holds them at a sampling rate of 1 mhz.模擬信號，并持有他們在1 mhz的采樣率。the sampling signal voltage ranges from 5vto 5 v. a/d采

43、樣信號的電壓范圍從5vto 5五的a / d converters convert analog voltage to digital quantities. 轉(zhuǎn)換器轉(zhuǎn)換成數(shù)字量的模擬電壓。thesynchronous data conversion produces data streams, and the 同步數(shù)據(jù)轉(zhuǎn)換產(chǎn)生的數(shù)據(jù)流，streams are stored in a cycle double-port memory.流被儲存在一個周期內(nèi)雙端口存儲器。 the cpld在cpldchip is used to generate a controlling impulse and

44、 controls the芯片用于生成一個控制脈沖和控制converters, ensuring that they work in order轉(zhuǎn)換器，確保他們?yōu)榱斯ぷ?。at last, cpu2在過去，cpu2的 executes wavelet algorithm and outputs the disturbance source.執(zhí)行小波算法和輸出的干擾源。 the cpu3 synthesizes fault determination result from pfu cpu3綜合故障pfu測定結(jié)果 and disturbance source result from twu to

45、output the faulted 從twu的干擾源的結(jié)果輸出的故障feeder.接駁。 the flowchart of the proposed scheme is shown in fig. 擬議計劃的流程圖如圖。 3.3 when a disturbance in the system is detected, current traveling當(dāng)檢測到系統(tǒng)中的干擾，當(dāng)前wave signals of all feeders sampled at 1 mhz are transferred在1 mhz采樣所有饋線波信號傳輸to data memory.數(shù)據(jù)存儲器。a fixed da

46、ta window containing 128 samples 一個固定的數(shù)據(jù)窗口，其中包含128個樣本is used.被使用。for each data window, four scales wavelet transforms對于每一個數(shù)據(jù)窗口，四個尺度小波變換are processed.處理。because capacitor banks are always installed for因為總是安裝電容器組power-factor correction in the substation, they will filter high-frequency components of c

47、urrent traveling waves在變電站功率因數(shù)校正，他們將過濾電流波的高頻分量。and high-fre-quency components of traveling waves attenuate more than rel-atively lower frequency components even along the same path和高頻率的行波組件衰減甚至超過低頻率的部分沿相同的路徑from the disturbance source to the measured point.從干擾源的測量點。thereby,因此，scale wavelet transform

48、 signal, which corresponds to rela-tively lower frequency components (31.125 khz 62.25 khz)尺度小波變換信號，它對應(yīng)關(guān)系較低的頻率成分（62.25千赫31.125千赫）of the signal, is chosen as the base signal to identify the faulted的信號，被選為基信號來識別故障feeder.。then the local modulus maxima of scale wavelet那么當(dāng)?shù)氐某叨刃〔O大值transform signals are

49、extracted.變換信號提取。because fault generated cur-rent traveling wave in faulted feeder is much higher than the由于故障產(chǎn)生在故障饋線電流旅行波遠(yuǎn)遠(yuǎn)高于waves in healthy feeders, and they share the same threshold, the健康饋線波，和他們分享相同的閾值，time of the first local modulus maxima in each feeder may be在每個支線的第一個本地的模極大值的時間可能是different.不

50、同。in fact, fault generated initial current traveling waves事實上，故障產(chǎn)生的初始電流波measured in all feeders should be at the same time.測量所有饋線，應(yīng)該是在同一時間。therefore,因此，if the first local modulus maxima in all feeders are compared如果當(dāng)?shù)氐谝荒O大值在所有饋線比較directly to identify the faulted feeder, the wrong result may be直接確定故障

51、饋線，錯誤的結(jié)果可能是obtained.獲得。so it is necessary to determine the time when fault因此，有必要的時間來確定故障時generated initial traveling waves arrive at the busbar.產(chǎn)生初始行波到達(dá)母線。the time時間is determined by comparing the time of the first local modulus通過比較當(dāng)?shù)氐牡谝荒r間確定maxima in all feeders, and the earliest time is output as t

52、he time在所有饋線最大值，最早的時候是隨著時間的輸出when fault generated traveling waves arrive at the busbar.當(dāng)故障產(chǎn)生的行波到達(dá)母線。 fig. 圖 4.4 power distribution system studie配電系統(tǒng)的研究。 this process is called time determination. 這個過程被稱為時間的確定。and scale wavelet trans-form signal at the time is used to represent the characteristics和尺度

53、小波反式形式在時間的信號是用來表示的特點fault generated current traveling waves of each feeder.故障產(chǎn)生目前各饋線的行波。in addi-tion, whether the disturbance is a fault should be determined by另外，是否干擾故障應(yīng)由comparing the busbar residual voltage with the previousl與以前相比母線的殘余電壓set value .設(shè)定值。if the busbar residual voltage is lower 如果母線的殘

54、余電壓低than the set value , the disturbance is not a fault.超過設(shè)定值，擾動是不是故障。 oth-erwise, the process goes to faulted feeder identification.oth，否則，這個進(jìn)程故障饋線鑒定。in the在faulted feeder identification, scale wavelet transform value故障饋線標(biāo)識，尺度小波變換值of all feeders at the time are compared with each other.當(dāng)時所有饋線相互比較.b

55、ecause 因為there are noises in the system, and low magnitude signals are系統(tǒng)中有噪音，低幅度信號more likely to be interfered by noises.更容易受到噪音干擾。 therefore, three highest 因此，三個最高scale wavelet transform values in magnitude are selected at尺度小波變換的幅度值的選擇 first, then the three signals are compared in polarity with eac

56、h 第一，然后比較三個信號極性與每個 other. 其他。the one with different polarity from the other two is iden-ti fied as the faulted feeder at last.一個與其他兩個不同的極性識別ti田間最后的故障饋線。 v. s imulation studiesa radial power distribution network is described in fig. 徑向配電網(wǎng)絡(luò)圖。 4.4。 it is這是a typical 10 kv distribution system which is si

57、mulated with the一個典型的10千伏配電系統(tǒng)，這是模擬 emtp. emtp的。 eight overhead feeders emanate from the busbar.八架空饋線發(fā)自母線。thetotal length of the feeders is about 95 km .饋線總長度約95公里。the overhead feeders架空饋線 contain some short cable segments in the substation, which are 包含在變電站的一些短的電纜段，這是omitted in the study.省略了研究 the l

58、ength of l1, l2, l3, l4, l5, l6, l7,l1的長度，二級，三級，l4的，l5，l6，l7的， and l8 is 8.1 km , 26.3 km , 2.5 km , 22.1 km , 5.4 km , 7.9 km ,和l8是8.1公里，26.3公里，2.5公里，22.1公里，5.4公里，7.9公里，8.8 km , and 14.1 km , respectively. 8.8公里，14.1公里，分別為。the 2 mvar capacitor bank 2無功電容is connected to the busbar for power factor c

59、orrection.連接到母線功率因數(shù)校正and 和small transformer is installed for substation power use.小型變壓器安裝變電站電源使用。 all feeders were modeled as three phase distributed param-eter cells using the respective feeder geometrical data: 所有饋線三相分布參數(shù)度計使用各自的幾何數(shù)據(jù)饋線為藍(lán)本： , , in which, and are 在其中，zero sequence impedance and capacitanc