變壓器油中氣體線上監測診斷系統

TRANSFIX™ DGA 500線上監測系統採用GE KELMAN公司專利的光聲光譜檢測(Photoacoustic Spectroscopy, 簡稱PAS)技術，為新一代高科技油中氣體/水分線上監測診斷系統，可準確檢測油中5種故障氣體及水分含量，為變壓器線上監測技術的最新突破產品。
擁有的優勢，所有類型的初期故障都可以通過監測氫氣位準來發現，緩慢侵蝕的絕緣紙老化可以通過監測一氧化碳來預測，各種程度的熱故障，包括電弧，可以被檢測和識別，這些都可通過變壓器維修來解決，而不是造成更昂貴的變壓器事故。
特別是，TRANSFIX™ DGA 500依循標準 IEC 60599 附錄 B 中描述的Duval 三角形 DGA 診斷，所引用的3種氣體（乙炔、乙烯和甲烷）的數值，適用於識別不同程度/溫度的熱故障以及存在高能放電故障。

主要優勢 :

• 能夠執行 Duval 三角法DGA 診斷。
• 可輕鬆升級為完整的九種氣體監測。
• 不需要載送氣體或校正氣體。
• 可連接至AC 或變電所DC 電源。
• 專用的PC軟體, 具有遠端控制、結果下載及故障診斷等功能, 且操作簡單。

產品應用 :

電力設施

• 維護關鍵性變壓適切的解決方案。
• 監測與遠程診斷相結合。

工業設備

• 降低因供電中斷而導致產線中止的風險。
• 最大限度地減少代價高昂的生產停機時間。

產品特點 :

尖端技術

• 油中氣體與水分監測: 可檢測5種故障氣體及水分。
• 可靠的取氣方式: 使用動態頂空平衡取氣, 非使用半透明膜或真空取氣。
• 無需耗材: 不需要載送氣體或校正氣體。
• 取樣頻率可達每小時一次，或用戶自定義取樣率。

易於使用

• 安裝上：無需停機，為用戶減少安裝成本和不便。
• 一旦檢測到嚴重問題，可將裝置升級為完整的九種氣體監測更進一步全面維護變壓器的安全。
• 完全內嵌式的處理器:  在預設的每6小時取樣一次的取樣率下, 可處理長達2年的資料。

可配置的警報

• 6個警報電驛接點， 每個都可由用戶設定。
• 依5種氣體、TDCG、水分位準及每種氣體變化速率作警報設定。
• 使用 Perception™ 軟體在本地或遠端設置或更改警報。
•  可使用注意模式及警告模式增加取樣頻率。

綜合解決方案

•  結合負載CT，根據變壓器的負載程度來分析DGA的結果。
•  備有廣泛的多種通訊及通訊協定選購。
•  整合GE Perception™變壓器管理軟體與其它軟體及SCADA 系統。

Duval三角診斷法和Perception 變壓器管理軟體

Perception的排行表及儀表板上風險指數和風險評分是可看到的

用於變壓器 DGA 結果的 Duval 三角形診斷方法由 Michel Duval 所提出，並在標準 IEC 60599 中進行了描述。

它基於三種烴類氣體 :  %甲烷 (CH₄)、%乙烯 (C2H₄) 和 %乙炔 (C2H2)進行故障類型判斷。在最新的IEC 標準導則中推荐使用Duval三角診斷法。
與比值法相比，Duval三角診斷法突出的優點是保留了一些由於落在提供的比值限值之外而被IEC 比率法漏判的數據。
使用Duval 三角形診斷時比值落點在哪個區域內，則該區域所對應的故障類型就是該比值對應的故障類型，所以它總能得出一種診斷結果並具有較低的錯誤率。

Duval三角診斷法和其他DGA診斷方法一樣，只有在懷疑有故障的情況下才可以應用，其依據是溶解氣體，特別是H₂的異常增加。它為GE的Perception
變壓器管理軟體可用的診斷方法列表的一部分( 另具有Rogers 比值法 , IEEE 主要氣體法  )。

另外，Perception 變壓器管理軟體所提供的變壓器風險指數排行，藉由以下三種獨立的時間跨度 :

• 長期的變化率
   藉由變壓器的日積月累 觀察其缺陷發展 （如 過熱缺陷，老化，某些類型的放電活動及整體情況惡化）
• 中期的變化率
  藉由有關於電力系統 如 負載 或環境條件的變化 觀察其 周期性的變化及其趨勢
• 短期的變化率
  從短期的角度來觀察 如 高耗能，高溫過熱，哪個需要採取緊急行動及調查觀察哪個有虛假的上升和缺陷需要觀察

為受監控的變壓器提供儀錶板和風險資訊，還可以將變壓器的健康狀況與其它相同資產的健康狀況進行比較，作為資產管理工具的一部分和展示其維護的優先順序。

Product Overview
The TRANSFIX™ DGA 500 is an on-line monitoring unit that measures individual dissolved gas and moisture and provides both on-line monitoring and key exploratory diagnostics. It uses the now well known PAS technology (Photo Acoustic Spectroscopy) made popular due to its accuracy, repeatability and lack of consumable through its bigger brother the Kelman™ DGA 900.
When a transformer’s insulation system is overstressed, gases are produced that dissolve in the transformer’s insulating oil. Dissolved Gas-in-oil Analysis (DGA) and moisture measurements are recognized as the most important tests for condition assessment of transformers and the best early indicators of developing faults.
All types of incipient faults are covered by the monitoring of hydrogen gas levels. Slowly eroding paper faults can be exposed through the monitoring of carbon monoxide. Various degrees of thermal faults, including arcing, can be detected and identified, often leading to a transformer repair rather then a much more costly transformer rebuild.
In particular, the TRANSFIX DGA 500 enables the well known Duval’s triangle DGA diagnostic described in Appendix B of IEC Standard 60599. It uses the value of 3 gases (Acetylene, Ethylene and Methane) and is suitable for identifying various degrees/temperature of thermal faults as well as the presence of high-energy electrical discharge faults.

Key Benefits

• Ability to perform Duval’s triangle DGA diagnostic
• Easily replaceable with a full nine gas unit
• Communicates data to allow remote diagnostic
• No carrier or calibration consumable gases required
• Available with AC or AC/DC power supply

Applications

Power Utilities

• Middle of the road solution for medium-criticality transformers
• Monitoring together with remote exploratory diagnostic

Industrial Plants

• Reduces the risk of process interruption due to power failure
• Minimizes costly production downtime

Cutting Edge Technology

• Five gases plus moisture in a single monitor
• Automated headspace gas extraction and state of the art photo-acoustic spectroscopy (PAS) measurement technology
• No carrier or consumable calibration
• gases required
• Capable of sampling frequency up to once per hour or user defined sample rates

Ease Of Use

• Easy installation: no outages required, reducing expense and inconvenience for user
• Easily swapable for a high end Kelman DGA 900 nine gas monitor, once serious issues are detected
• Over two year’s worth of data stored internally at six-hourly sampling rate

Configurable Alerts

• Six user configurable alarm relay contacts
• Alarms can be set on gas or moisture ppm levels or on rate of change (ROC)
• Alarms can be set or changed locally or remotely using Perception™ software
• Caution and alarm modes can be used to automatically increase sampling frequency

Integrated Solution

• Integrated load CT allows DGA results to be analysed against the loading of the transformer
• Extensive remote communications options
• Integrates into GE's Perception software

Duval’s Triangle & Perception Software

The Duval Triangle diagnostic method for transformer DGA results was developed by Michel Duval, and is described in IEC standard 60599.
Concentrations (ppm) of methane (CH₄), ethylene (C₂H₄), and acetylene (C₂H₂) are expressed as percentages of the total (CH₄ + C₂H₄ + C₂H₂) and plotted as a point (%CH₄, %C₂H₄, %C₂H₂) in a triangular coordinate system on a triangular chart which has been subdivided into fault zones. The fault zone in which the point is located designates the most likely fault type which produced that combination of gas concentrations.
The Duval Triangle method, like any other DGA diagnostic method, should be applied only when there is some suspicion of a fault, based on an abnormal increase in dissolved gases and H₂ in particular. It is part of the list of diagnostic methods available in GE’s Perception software, depending on the various gas concentration data that are available.
The Transfix DGA 500 integrates seamlessly with Perception to provide not only dashboard and risk information for the transformer monitored but also to compare that transformer’s health with that of other similar assets and showcase its priority as part of the fleet management tool.