發(fā)電機組紫外成像儀介紹

1、Ofils proprietary materialCannot be used without Ofils explicit consentHV Rotating Machines高壓旋轉機高壓旋轉機Ofils proprietary materialCannot be used without Ofils explicit consentCIGRE Study Committee SC11, EG11.02, “Hydrogenerator Failures Results of the Survey“, (2003)2003年國際大電網研究委員會“水輪發(fā)電機故障調查結果”Statisti

2、cs of 1,199 Hydro Generators1,199部水輪發(fā)電機資料統(tǒng)計部水輪發(fā)電機資料統(tǒng)計Insulation failure is a significant root cause for the breakdown of high voltage rotating machines.絕緣故障是高壓旋轉機故障的主要根源Ofils proprietary materialCannot be used without Ofils explicit consentInterface Interface DustingDusting界面塵埃界面塵埃Slot Exit Slot Exi

3、t DustingDusting槽口塵埃槽口塵埃Slot Section Slot Section DustingDusting狹槽部分狹槽部分塵埃塵埃End Winding End Winding DustingDusting繞組末端繞組末端塵埃塵埃Connection Connection DustingDusting連接處塵埃連接處塵埃 SLOT DISCHARGE 狹槽放電狹槽放電 Occurs when the coils become loose, causing the winding capacitive charging current to be dissipated to

4、 ground through concentrated contact points. 發(fā)生在當線圈變松弛時，導致繞組 電容充電電流電流通過集中接觸點從地從地 線被空耗掉線被空耗掉。 Left to continue, this phenomena will eventually compromise the ground wall insulation system and result in a winding failure to ground. 照此情形下去，這種現象最后將危危及主絕緣系統(tǒng)的安全及主絕緣系統(tǒng)的安全，并導致繞組繞組的地線故障故障。Ofils proprietary ma

5、terialCannot be used without Ofils explicit consentOfils proprietary materialCannot be used without Ofils explicit consentAny kind of conductive contamination from moisture or oil mixed with dust/dirt affects a machine as electrical tracking develops across the blocking or along the end arms. 當電子軌跡穿

6、越阻隔或沿臂端擴展，各種因潮濕或混雜灰塵混雜灰塵/污垢污垢的油類而形成的傳導污染傳導污染 會影響機器。The electrical tracking occurs since a conductive path between two adjacent coils of different potential is created, and often from different phases. 由于在在2個相鄰的不同潛能線圈之間形成了傳導路徑個相鄰的不同潛能線圈之間形成了傳導路徑，并且通常來自不同相線，電子軌跡軌跡因此就會出現。This means once the contaminati

7、on is removed, this corona activity will cease. 也就是說，一旦污染被清除污染被清除，電暈活動將會停止電暈活動將會停止。Left uncorrected, permanent phase-to-phase or phase-to-ground deterioration may occur and eventual failure of the ground-wall is possible. 留下錯誤的、永久性相線對相線或相線對地線惡化惡化，并可能造成主絕緣故障主絕緣故障。Ofils proprietary materialCannot be u

8、sed without Ofils explicit consentCorona Spots電暈點 Corona severity indication Photons/ Sec 電暈嚴重顯示 光子/ 每秒 GE發(fā)電機發(fā)電機Ofils proprietary materialCannot be used without Ofils explicit consentVoltage 24Kv 電壓24千伏 Voltage 31Kv 電壓31千伏Corona Spots電暈點 Quantitative indication 量化顯示Ofils proprietary materialCannot b

9、e used without Ofils explicit consent地點：以色列地點：以色列 Alon Tavor2003年年5月月20日正常操作電壓下，發(fā)電機定子產生的弱電日正常操作電壓下，發(fā)電機定子產生的弱電暈暈Ofils proprietary materialCannot be used without Ofils explicit consentThe Case 個案個案:Stress-Grading Systems in Hydro-Generators水輪發(fā)電機應力分級系統(tǒng)水輪發(fā)電機應力分級系統(tǒng) (Hydro-Qubec 魁北克水利發(fā)電公司魁北克水利發(fā)電公司)Present

10、ed in 展示于展示于:Iris Rotating Machine ConferenceJune 2007, San Antonio, TX 22007年年6月在圣安東尼奧舉辦的愛麗絲旋轉機會議月在圣安東尼奧舉辦的愛麗絲旋轉機會議Priority 1 signs of the corona effect Ofils proprietary materialCannot be used without Ofils explicit consentTHE FAULT 缺陷缺陷Stress-Grading coatings controls the E field in stator end-wi

11、ndings 要點- 分級鍍膜在定子終端繞組控制控制E場場Such coatings are tricky to design and implement. 這個鍍膜對于設計和實用來說有些微妙。The white powder attack and decompose the insulating material. 白色粉末在攻擊和分解絕緣材料。Inspections revealed white powder at the junctions and grading coatings in stator windings which results from surface dischar

12、ges. 檢查顯示顯示位于接合處以及定子繞組分級鍍膜上的白色粉末因表面放電而產生白色粉末因表面放電而產生。Such defects were even seen on stator windings with only 4 years of service. 這個缺陷甚至可以在僅服務服務4年年的定子繞組上發(fā)現?！癈orrective action must be taken to remedy the deterioration before it becomes critical or breakdown. This entails shutting down generating unit

13、s, which is clearly undesirable in an increasingly competitive market for electricity sales”“必須采取改進措施在問題嚴重或故障發(fā)生之前消除惡化。以避免蒙受關閉發(fā)電裝必須采取改進措施在問題嚴重或故障發(fā)生之前消除惡化。以避免蒙受關閉發(fā)電裝置而造成損失，這在電力銷售日益競爭激烈的市場是不期望看到的置而造成損失，這在電力銷售日益競爭激烈的市場是不期望看到的”Signs of discharges on a winding after just 4 years of service一個服務4年繞組的放電跡象Ofi

14、ls proprietary materialCannot be used without Ofils explicit consentTHE PHENOMENON 現象現象When E field along the surface of the end-winding coating is higher than the dielectric breakdown field of air Corona will appear. 當沿著終端繞組鍍膜的E場高過非傳導性的空氣絕緣，電暈就會出現。The local current density can be very high causing

15、it to burn. 局部電流密度會非常高，導致燃燒。This will cause the Corona to appear in the slot and may lead to breakdown of the ground- wall insulation. 這將導致電暈在狹槽出現，可能引發(fā)主絕緣故障。Corona will occur due to: scratches, chipped paint, inadequate spacing, miss-positioned RTD cable and more. 電暈的產生是因為：刮痕、漆面剝落、間隙過窄、錯位RTD導線等?！癈or

16、ona will cause breakdowns inside the slot near the slot exit with marked signs”“電暈會在狹槽出口標注處導致故障電暈會在狹槽出口標注處導致故障”O(jiān)fils proprietary materialCannot be used without Ofils explicit consentCORRECTIVE ACTIONS 改正措施改正措施Testing ensures that defects did not slip in during assembly, PD measurements can be used t

17、o quantify the intensity of corona discharges at junctions. 檢測可以確保在安裝過程中摒棄缺陷，局部放電測量可以量化結合處的電暈放電強度。Using silicon carbide stress-grading tape instead of the paint used earlier. 用碳化硅應力-分級膠帶來取代早期使用的上漆法。Spots with visible PDs must be repaired by sanding, cleaning or applying stress-grading paint. 可見放電點必須

18、通過打磨、清理或采用應力分級漆。signs of the corona effect 電暈效果的痕跡電暈效果的痕跡“Corona inception voltages as low as 5.2 kV were recorded at the stress-grading junction. 電暈的初始電壓低至電暈的初始電壓低至5.2 kV，記錄在應力分級接合處。，記錄在應力分級接合處。Such values are clearly unacceptable since bars on the phase side of the stator-winding are permanently s

19、ubjected to higher voltages”這個值很明顯不能接受，因為定子繞組相線一側的鐵柵這個值很明顯不能接受，因為定子繞組相線一側的鐵柵永遠面對的是高壓。永遠面對的是高壓。Ofils proprietary materialCannot be used without Ofils explicit consentRESULTS OF UV INSPECTION 紫外檢測結果紫外檢測結果Photographs were selected to clearly show defects. 選定照片清楚顯示缺陷。選定照片清楚顯示缺陷。Maintenance staff could t

20、hus assign a priority to each site showing signs of the Corona. 維修人員可以根據電暈痕跡的程度排定維修的優(yōu)先次序。維修人員可以根據電暈痕跡的程度排定維修的優(yōu)先次序。UV camera view of the corona discharge at the junction紫外成像儀觀測接合處的電暈放電UV camera view of the corona discharge at the junction紫外成像儀觀測接合處的電暈放電Ofils proprietary materialCannot be used without

21、 Ofils explicit consentRESULTS FROM VARIOUS INSPECTION MODES 各種檢測模式結果各種檢測模式結果Capacitive Coupler 電容耦合電容耦合Often impossible to detect the external discharge trigger threshold at the junction. 通常無法在接合處引發(fā)界限檢測到外部放電。Cannot be used for simultaneous detection on several bars. 不能用于同時檢測幾條線管。Ultrasonic 超聲波超聲波Se

22、nsitive to both internal and external discharges. 對內部和外部放電都很敏感。Impossible to get close enough to distinguish between internal and external discharges. 無法接近區(qū)分內部和外部放電。 Detection from a distance greatly reduces the instruments spatial resolution. 遠距離檢測會極大降低儀器的空間解析度。Impossible to take simultaneous measu

23、rements on several bars. 無法同時檢測幾條線管。Ofils proprietary materialCannot be used without Ofils explicit consentRESULTS FROM VARIOUS INSPECTION MODES 各種檢測模式結果各種檢測模式結果Corona Probe electromagnetic 電暈電磁探測器電暈電磁探測器Detection is highly localized, covering an area of only 1 x 5 cm. 檢測只限局部，覆蓋范圍只有1 x 5 cm。The dial

24、 gauge supplied with the probe could not detect corona discharges 與探測器一起提供的度盤式指示器不能偵測到電暈放電不能偵測到電暈放電Naked-eye 裸眼裸眼“Blackout test”, precise but requires for each set of bars, a 15-minute wait in complete darkness for the eye to become sensitive enough. “熄燈測試”，準確，但需要對每套線管進行偵測，在黑暗狀態(tài)下需要等待15分鐘使 眼睛足夠敏銳。Ofi

25、ls proprietary materialCannot be used without Ofils explicit consentRESULTS FROM VARIOUS INSPECTION MODES 各種檢測模式結果各種檢測模式結果UV camera observations 紫外成像儀觀測紫外成像儀觀測 The most sensitive method and can be used to measure several bars simultaneously. 最靈敏的方法最靈敏的方法，可以用來同時檢測幾個狹長連線同時檢測幾個狹長連線。It is very safe sinc

26、e there is no need to be near the bars and it can be used under regular lighting conditions. 非常安全非常安全，因為不必靠近線管，而且可以在正常光線正常光線條件下使用。Observations must be made using a camera with adequate sensitivity to ultraviolet radiation of wavelengths shorter than 300 nm (UVB and UVC). 必須使用對短于300nm (UVB 和 UVC)波長的紫外輻射具有足夠靈敏度足夠靈敏度的成像儀觀測。Testing 80 bars by batches of 7 to 10 bars takes about one-half day and is qu