Differential equation model of single penstock multi‐machine system with hydraulic coupling. Issue 7 (6th March 2019)

• Record Type: Journal Article
• Authors: Zeng, Yun; Qian, Jing; Guo, Yakun; Yu, Shige
• Is Part Of: IET renewable power generation. Volume 13:Issue 7(2019)
• Page Start: 1153
• Page End: 1159
• Publication Date: 2019-03-06
• Subjects: optimisation -- power system stability -- pipes -- turbines -- differential equations -- numerical analysis -- hydroelectric generators -- hydroelectric power stations -- hydraulic systems -- hydraulic turbines; single penstock multimachine system -- control design -- hydro turbine governor -- multimachine differential equation model -- hydraulic coupling model -- joint model -- hydraulic system -- hydraulic‐mechanic‐electric coupling -- dynamic head -- common penstock -- differential item; Renewable energy sources -- Periodicals; 333.79405
• DOI: 10.1049/iet-rpg.2018.6123
• Languages: English
• ISSNs: 1752-1416

Abstract

Abstract : Calculation of the hydraulic coupling in the single penstock multi‐machine (SPMM) is one of the main obstacles for control design of the hydro turbine governor. In order to resolve this problem, a multi‐machine differential equation model suitable for control design and stability analysis is established in this study. First, the multi‐machine differential equation with the hydraulic coupling model is then established to facilitate building the joint model of the hydro turbine with the hydraulic system and the generator considering the hydraulic‐mechanic‐electric coupling. Second, the dynamic head in the common penstock satisfying the superposition principle is revealed. This means that the dynamic head in the common penstock can be calculated by using the state variables of the branch pipe. Third, simulation reveals that the differential item in the hydraulic coupling is the main factor affecting the computational convergence. As such, the approximate method ignoring the differential item in the hydraulic coupling is proposed to solve the problem of computational convergence of the SPMM. Finally, the classical method of characteristic (MOC) is employed to verify the proposed model. The results show that the proposed model has higher accuracy and is easy to connect with the non‐linear model of the generator.