Research On Canal Control Models For Long Distance Water Conveyance Systems And Unsteady Flow Simulation

The operation and control is one of the most important work for long-distance water conveyance project, especially for complex large-scale canal system, distance is long, control points is more, distributing asymmetrical, and water supply need uninterrupted. So the control is not easy. Any mistake can lead to serious results such as liner-plates damaged or dam banks slipped. The research about new, high quality and needs-satisfying control models and unsteady flow simulation system for long-distance water conveyance canals is important and necessary.To large-scale water conveyance systems with stair pumps, the power cost is high. For reducing the cost of transmitting water, a new optimal methodology used control flow in canal was presented based on optimal methods and different power-network prices in peak-load and low-load periods for a long distance water conveyance project. The result of an application example shows that the cost can be reduced largely, the minimum frequent of switch can be achieved, flow in canal can be stabilized and the safety of the canal can be ensured.A two-step model, which can make the deviant water levels restore to the normal position in minimum duration was present for long and large-scale water conveyance canal based on the volume control method, optimum technique and experiences in operation and control works. The merits using this model are (1) Water levels arrive to the goal level during minimum time. The simulations show that the time that the water levels reach the target levels and keep them stable can be reduced from a few days using classic method to a few hours using this optimum method. (2) The drop and rise of flow rate is constrained, so the flow is stable which can avoid landslip because of water level rapid fall.A method combining normal PID and RBF neural network method was presented according to the characteristic of canal transmitting water. It has merits of self-studying, self-adapting, strong fault tolerant and robustness. Through hydraulic simulating, the results show that in the process of RBF PID control, the method can adjust the parameters at a best state,the water level overshoot is smaller and the response is quicker. It not require to choose and computer parameters complexly, and can be used to the real-time control of nonlinear system such as canal transmitting water.The paper presents a parameter self-adapting canal flow fuzzy PID control combining fuzzy control merits with PID control features of simple structure and stability. Through fuzzy inference method, the model uses the canal automation history control experiences to realize the optimization of parameters and make the control process at the best state. The simulation results of an adaptive fuzzy sample show that using the adaptive fuzzy PID control canal flow, the overshoot is reduced, the dynamic behaviors are improved. This paper presented a new step-size PID control method for canal flow according to the actual canal-flow operation for canal of cool area. In the step-size PID canal control process, it is not once time to set goal water level statically, but set many temp goal that approach final goal step by step. This can control the water drop speed, and make the flow in canal steady. The Step-PID has the characteristics of simple, better controllability and operability. The simulations show that the water fluctuation and overshoot are smaller using Step-PID. The method is suitable to open channel flow with drawdown speed is hard limited or canal flow under ice.A nonlinear open channel PID control method was proposed according to the nonlinear and hysteretic nature of canal flow control. The nonlinear functions of proportional and integral parameters were created based on the relatively best tendency. The unsteady flow of canal nonlinear PID control process is simulated last. The simulation results show that the response of nonlinear PID control speeds is faster, the overshoot is less rather than that of normal liner PID control method.The unsteady flow simulation systems of canal operation and automation control have been researched and developed for long distance and large-scale water conveyance canals. Users can use either characteristic line method or implicit format to simulate. It can be used to simulate unsteady flow processes of operation and control, to simulate, verify and develop auto control models, to simulate the hydraulics and flood of river network. The systems include some classic canal control models and RBF+PID, fuzzy+PID, Two-Step optimum control for gravity canal, cost optimum control for water conveyance system with pumps.