【正文】 ction toward the phase B. Yaxis direction is up and perpendicular to the tank bottom. Z axis is perpendicular to the tank wall from outside to inside.. The length of tested transformer is , its width is and its high is . Set up the transformer geometric model as X = , Y = and Z = . Transformer PD location coordinates the sensor R15I is used that have 18 channels, builtin ultrasonic pulse 40 db and preamplifier resonant frequency 150kHz. There are six sensors placed on the positive and negative surface of the transformer, four sensors placed on the two sides transformer, and two sensors placed on the transformer bottom. after finishing sensor placement, the threedimensional model of the transformer is shown in Figure 5. 西安工程大學(xué)畢業(yè)設(shè)計(jì)（譯文） 7 The threedimensional model of the transformer with sensors (2) Parameter setting parameters setting of ultrasonic detection for transformer insulation fault are threshold value, sound speed, sample rate, filter range and so on. Set the amplitude of ultrasonic signal is 45dB, and the float threshold value is 4dB. As magic noise energy of transformer core concentrated in the 10~65kHz frequency range and transformer noise is focused on below 15kHz frequency band, the strongest frequency band in the vicinity of . The filter frequency analog filters lower limit is set to 1kHz, upper limit is 400kHz, and sampling rate is 1MSPS. Set the velocity of ultrasonic signal is 1400m/s, the minimum impact is 4 and maximum impact is 8. According to desired output, we can set hit to time, energy to time, amplitude to time, and threedimensional scatter plot, etc. This test use multichannel to show the plot of hit to time which facilitated analysis and parison to locate the transformer insulation fault. (3) Result of PD detection It took 6 hours to locate the transformer insulation fault. There are obvious sudden and high amplitude acoustic emission signal during the testing. The distribution of ultrasonic signal amplitude is a large range, and the most amplitude is 2810dB. signals triggered frequently. Some channels can always capture the signal. Ch1, Ch2, Ch7, Ch8, Ch13, Ch14 signal have PD characteristics. These sixchannel signal meet the ultrasonic signal characteristics. the ultrasonic signal amplitudes of Ch7 and Ch14 are greater, respectively 1892dB and 2810dB. Therefore, we think that these six channels may be received partial discharge signal and the corresponding discharge points concentrated in the near block ic high of transformer phase A. 西安工程大學(xué) 本科 畢業(yè)設(shè)計(jì)（譯文） 8 Scatter plot of transformer insulation fault location shows that: discharge points focus on the channel 1,2,7,8,13,14 which is in accord with the results of the sensor receiving. So, if there is partial discharge of transformer insulation, it should concentrate in the vicinity of ic high seat of transformer phase A. The number of partial discharge can be tested by partial discharge test carried out at the same time. B. Transformer Partial Discharge Testing When we have transformer insulation ultrasonic detect, carry out partial discharge testing at the same time to test the number of partial discharge. Transformer main parameters: Type: SFPSZ7120210/220 Rated voltage:（ 220177。因此，當(dāng)變壓器在運(yùn)行時(shí)，檢測(cè)變壓器局部放電是非常必要的和重要的。下面用一個(gè)例子來驗(yàn)證這 種方法。 因此，在操作和制造變壓器時(shí)，檢測(cè)局部放電是很有必要和重要的 。局部放電試驗(yàn)可以有效地檢測(cè)放電 量 ，但不能準(zhǔn)確定位局部放電。 西安工程大學(xué)畢業(yè)設(shè)計(jì)（譯文） 13 當(dāng)變壓器內(nèi)部絕緣局部放電發(fā)生時(shí)， 超聲波信號(hào)將形成球面波，并以 1400m/s的速度在變壓器油箱中傳播。檢測(cè)原理如圖 1 所示。 因?yàn)樽儔浩鲀?nèi)部結(jié)構(gòu)很復(fù)雜 ,這是復(fù)合不同的材料 ,如石油、銅、硅鋼等等。我們使用多個(gè)傳感器 ,更多我們得到準(zhǔn)確的位置。在測(cè)試之前， 將方波 與 500PC 電荷 充電，注入高（中 ）電壓最后一層殼體絕緣紙校準(zhǔn)放電的數(shù)目。 ③ 測(cè)試補(bǔ)償 考慮到 變頻電源單元和可能的共振的能力， 放電 反應(yīng)器用于在測(cè)試補(bǔ)償電容電流。電壓高達(dá) 20%和 50%的 3mU 期間，監(jiān)控補(bǔ)償電抗器和變壓器的電流，并決定增加或減少補(bǔ)償電抗器的容量。為了防止 變壓器發(fā)生故障，電源伴侶停止變壓器，由李政超聲波檢測(cè)方法，評(píng)價(jià)其絕緣狀態(tài)，并檢測(cè)可能的局部放電定位。 Z軸垂直于罐壁由外而內(nèi)的。有六個(gè)傳感器放置在變壓器的正和負(fù)的表面，四個(gè)傳感器放在兩側(cè)，變壓器，和兩個(gè)傳感器放置在變壓器底部。由于變壓器鐵心的磁噪聲能量集中在 10? 65kHz的頻率范圍和變壓器的噪聲集中在低于 15kHz的頻帶，在 。該測(cè)試使用多通道顯示，這有利于分析和比較找到變壓器的絕緣故障。通道 1 14有局部放電信號(hào)特性。所以，如果有變壓器絕緣局部放電，它應(yīng)該集中在變壓器 A相，局部放電數(shù)漫畫高座位附近可以通過局部放電試 驗(yàn)同時(shí)進(jìn)行測(cè)試。用 16000pF電容補(bǔ)償無功功率容量。 圖 8 電壓為 3mU 時(shí)的局部放電量 局部放電的數(shù)目達(dá)到 5010pC，當(dāng)測(cè)試電壓增加至 3mU 。根據(jù)同時(shí)進(jìn)行局部放電試驗(yàn)，我們知道變壓器局部放電的數(shù)量遠(yuǎn)遠(yuǎn)超過了部分排放限值的國(guó)家標(biāo)準(zhǔn)。一個(gè)案例驗(yàn)證了超聲檢測(cè)的精度的電。 參考文獻(xiàn) [1] Xiaorong Wang, Bei Wei, Guanjun Wang. A new partial discharge electrical location method of transformer winding. High Voltage Technology. 1999,25(3): 2729 [2] Bengtsson C. Status and trends in transformer monitoring. IEEE Transaction on Power Delivery. 1996,11(3):13791384 [3] Tatsuo Takada, Acoustic and Optical Method for Measuring Electric Charge Distributions in Dielectrics. IEEE transactions on Dielectrics and Electrical Insulation, 1999, 6(5):519547 西安工程大學(xué)畢業(yè)設(shè)計(jì)（譯文） 21 [4] Caixin Sun, Wenqi Zhao. Electrcalacoustic and acousticacoustic locating method of transformer PD source and its evaluation study. Transactions of China Electrotechnical Society. 1997,12(5): 4952,60 [5] H. G. Kranz, A PD measuring and evaluation system based on digital signal proce