Developing a decentralized proportional-integral automatic control system and evaluating its performance in improving the operation of the Abshar irrigation district’s main canal

Articles in Press

Document Type : Research Paper

Authors

1 Water Engineering Department, Faculty of Agricultural Technology, University College of Agriculture & Natural Resources, University of Tehran,

2 Water Engineering Department, Faculty of Agricultural Technology, University College of Agriculture & Natural Resources, University of Tehran

3 Dept. of Water Engineering, Faculty of Agricultural Technology (Aburaihan), University College of Agriculture & Natural Resources, University of Tehran,

Abstract

An automatic PI control algorithm was developed to operate a canal in the Abshar irrigation district and evaluate its performance under normal and water shortage scenarios. The study innovatively developed a simplified integral-delay (ID) mathematical model for simulating hydraulic flow in the main canal, along with a decentralized automatic control operation model (PI). The automatic operation model was coupled with the hydraulic simulation model in MATLAB, and the proportional and integral coefficients of each controller were determined using the system identification (SI) method. The simulation results demonstrated that the decentralized proportional-integral control system was capable of implementing desirable operation along the main irrigation canal under normal operation scenarios. However, with the onset of water shortage conditions, water distribution improved in upstream and middle canal reaches while becoming uncertain in downstream canal reaches. Intensified water shortage scenarios, coupled with fluctuations, resulted in desirable water delivery conditions only in the upstream canal while experiencing weak operation in the downstream canal. In such conditions, the maximum calculated error ranged from 17 to 22 centimeters and from 35 to 45 centimeters for reaches 11 to 15 and 16 to 20, respectively. Evaluation indices, including MAE, IAE, and STE, were obtained with values ranging from 0.096 to 0.172, 0.123 to 0.991, and 0.089 to 0.592, respectively. The results indicated that the designed decentralized controller transferred the effects of unconventional phenomena at the canal inflow towards the downstream, resulting in disrupted and inappropriate surface water distribution in downstream canals.

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Iranian Journal of Soil and Water Research

Articles in Press, Accepted Manuscript
Available Online from 18 May 2024

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