Research On Comprehensive Energy Saving And Coordinative Optimization Control Of Distributed Pumping Stations In Urban Drainage Systems

Urban drainage systems are non-linear coupled system with multi-input and multi-objective complexity of the wide geographical distribution. Unreasonable emission control method will cause high energy consumption of pumps and pollution of sewage overflow. Aiming at the problem of comprehensive energy saving and coordinative optimization control of distributed pumping stations in urban drainage systems, the main research topics and contributions of the dissertation are:(1) A pump group control based urban drainage control systems model was established to describe the urban drainage systems containing unexpected pipeline delay and mutual relations between pumping stations. According to the affinity laws of pump, a general formula for variable-speed characteristic of pump group was derived, then an exponential law based numerical model of variable-speed pump group was obtained. Based on the proposed numerical model, an optimal real-time flow measurement method was discussed. The effectiveness of the measurement method was tested through experiments.(2) Take the energy-saving operation of distributed pumping stations as the target, the energy-saving mechanism that integrates reducing static head and dynamic head was analyzed. Then, two optimize energy-saving methods for variable-speed pump which are applicable to different conditions were presented: 1) A high efficient self-adaptive control method follows the variation of static head. This method is suitable for the situation that large range of static head is difficult to control and the ratio of head and efficiency is not satisfied with the law of diminishing.2) An integrated optimal control method considering the power and efficiency of pump simultaneously takes the ratio of head and efficiency as the performance indicator. This method is suitable for the situation that static head is easy to self-regulation and the ratio of head and efficiency is satisfied with the law of diminishing. The energy-saving effect of two method was compared through experimentation.(3) Addressing the optimize coordination demand of large geographically distributed urban drainage systems, and the decline in the quality control after the introduction of networked control, A hierarchical coordinate urban drainage networked control systems was presented. An adaptive parameter estimation law with initial value matching was proposed. Based on the proposed law, a multi-model switching control method integrated of predictive functional control (PFC) was developed. The simulation results show that it has better performance of system identification that applying the proposed parameter estimation law to Regional Station closed-loop control systems instead of using ARMAX model, and the proposed control method has good robustness.(4) In order to improve Combined Sewer Overflow / Sanitary Sewer Overflow (CSO / SSO) problem brought about by differences in operating conditions of spatially distributed drainage systems, a coordinated discharge scheduling method was discussed,which is adapt to distributed pumping stations in urban drainage systems. By the discharge scheduling method and introduction of the interaction prediction method, optimal control will be converted into multi-objective optimization integrating optimal control and comprehensive scheduling. The simulation results show that coordinative optimization is able to effective use of the capacity of the distributed drainage pumping stations in terms of conditions diversity when the inflow does not exceed the total capacity of drainage pumping station in every level, which ensures overall none sewer overflow. This coordinative optimization method does not affected by the changes of pipeline delay and decision-making variables.(5) A multi-channel, parallel network architecture based on the open standards Ethernet and Internet was designed. In the basis of the architecture, coordinative network scheduling of multi-type and multi-loop controllers of distributed pumping stations in urban drainage networked control systems was implemented, which provide a software platform for optimal hierarchical control of the coordination of distributed pumping stations in urban drainage systems.