考慮發電機組非等熵效應之抽汽冷凝式汽電共生廠最佳調度研究

STUDY OF OPTIMAL OPERATION OF EXTRACTION- CONDENSING TYPE COGENERATION SYSTEMS BY CONSIDERING THE NON-ISENTROPIC SITUATION

劉育銘(Yu-ming Liu)

指導教授 ： 陳斌魁

大同大學/電機資訊學院/電機工程學系所/碩士(2007年)

摘要

本論文依熱力學理論分析汽電共生廠之抽汽冷凝式蒸汽渦輪發電機機組特性，一般I/O Curve關係式將抽汽段溫度、壓力固定，而忽略各個抽汽段單位熱焓值變化；本文考慮非等熵效應時汽輪機於不同運轉點造成溫度、壓力改變而影響單位熱焓值變動，並探討與機組出力的關係，因此找出符合實際情況的I/O Curve。再以〝實數修正基因遺傳演算法〞(Real-Code Modified Genetic Algorithms)求解汽電廠最佳化調度策略。求解最佳化運轉問題時，必須納入機組運轉限制條件，滿足蒸汽及廠內用電需求後，再按時間電價不同，調整機組出力以獲得汽電廠最大售電利潤，因此可求得各不同時段不同運轉狀況下最佳化調度成本。此外，本文也考慮備用電力及評估燃油價格變動時對JP-2停機效益，將JP-2停機仍要求維持電力與蒸汽需求，由此可看出目前廠內運轉可靠性與是否有最大利潤。
以實數修正基因遺傳演算法求解最佳化，除了可以避免傳統求解最佳化問題必須考慮可微分性、連續性，而且較容易解決相關限制式，採實數修正法可免除二進位反覆編碼、解碼的動作，因此能加強搜尋最佳解的能力及速度。本文以一個汽電共生廠為實例，將模擬結果與原始資料比較，驗證所提方法確實可行。

關鍵字

汽電共生、最佳化、非等熵

並列摘要

The main purpose of this thesis is to find the optimal operation strategy for cogeneration system with extraction condensing turbines by applying Real-Code Modified Genetic algorithms (RMGA). The characterization of steam turbine is base on thermodynamic theory. In order to approach the actual I/O curve, the relationship between enthalpy difference and power output in the non-isentropic situation is considered. The primary requirement of the strategy is to meet process steam demand and electric load. Then, the optimal load allocation for boilers and generators under considering the time-of-use (TOU) rates is adjusted to reduce production cost and save energy. Besides, the fluctuantion of oil price is also considered to discuss the shutdown unit, JP-2, for the maximum profits.
To solve the optimal operation strategy with Real-Code Modified Genetic algorithms (RMGA) can avoid the differential and continuity problems; meanwhile it is easy to solve operation constraints. Modifying Real code can neglect, encode and decode repeatedly; therefore search speed is much rapider than the ordinary method. Finally, the simulation results of many different situations have been compared with the operation record. It is fount out that the algorithm does work, and the cited sample systems do have space to get extra profit. In addition, the fuel price and TOU rates play and important role in optimum operation of a cogeneration plant.

並列關鍵字

non-isentropic ； optimal ； cogeneration

參考文獻

[2]B.K. Chen and C.C. Houng, “Optimum operation for a back-pressure cogeneration system under time-of-use rates,” IEEE Transactions on Power Systems, Vol. 11, No. 2, PP.1074 - 1082, May 1996.

[3]Y.Y. Hong and C.Y. Li , “Genetic algorithms based economic dispatch for cogeneration units considering multiplant multibuyer wheeling,” IEEE Transactions on Power Systems, Vol. 17, No.1, PP.134 - 140, Feb. 2002.

[6]M.T. Tsay, W.M. Lin and J.L. Lee, “Application of evolutionary programming for economic dispatch of cogeneration systems under emission constraints,” International Journal of Electrical Power & Energy Systems ,Vol. 23 ,No 8, PP.805-812 ,Nov. 2001.

[11]T.Y. Wu, S.S. Shieh, S.S. Jang and C.C. Liu., “Optimal Energy Management Integration for a Petrochemical Plant Under Considerations of Uncertain Power Supplies,” IEEE Transactions on Power Systems, Vol 20, No3, PP.1431 - 1439, Aug. 2005.

[12]Robin Smith, “Advanced Site Utility Systems,” Department of Process Integration UMIST.