Abstract
In a sudden load increasing process (SLIP), the hydroelectric generating system (HGS) experiences a severe vibration response due to the sudden change of the hydraulic-mechanical-electric parameters (HMEPs). The instability of HGS limits the ability of sudden load increase, and its flexibility and reliability are reduced. Thus, in this study, a new transient nonlinear coupling model of HGS is proposed, which couples the hydro-turbine governing system (HTGS) and the hydro-turbine generator shafting system (HGSS) with the hydraulic-mechanical-electric coupling force, rotating speed, flow rate, hydro-turbine torque, electromagnetic torque, and guide vane opening. By using numerical simulation, the influences of different HMEPs on the vibration characteristics of HGS in SLIP are analyzed. The result shows that, compared with stable operating conditions, the vibration amplitude of HGS increases sharply in SLIP. The increase of the sudden load increasing amount, blade exit flow angle, mass eccentricity and excitation current, and the decrease in guide bearing stiffness and average air gap between the stator and rotor cause abnormal vibration of different degrees in the HGS. Hydraulic factors have the greatest influence on the nonlinear dynamic behavior of HGS. The maximum vibration amplitude of HGS in SLIP is increased by 70.46%, compared with that under stable operating conditions. This study provides reasonable reference for the analysis of the nonlinear dynamic behavior of HGS in SLIP under the multiple vibration sources.
Highlights
Hydropower is an environmentally friendly renewable energy, which has been widely used all over the world, and is of great significance to sustainable development [1,2,3]
When hydroelectric generating system (HGS) regulate the peak and frequency of the power system, it is impossible to avoid a series of transient processes, such as load increase and decrease [7]
Compared with the large power system, the sudden load change has a greater impact on single-machine single-load power systems (SMSLPSs), which aggravates the impact of hydraulic-mechanical-electric parameters (HMEPs) on HGS, and causes severe vibration of the HGS [9,10]
Summary
Hydropower is an environmentally friendly renewable energy, which has been widely used all over the world, and is of great significance to sustainable development [1,2,3]. Zhang et al established a hydraulic excitation model induced by a draft tube vortex, and analyzed the vibration characteristics of HGS in a sudden load increase of 10% [22]. Guo et al established an HGSS model by using the dual-disc rotor system, and explored the vibration characteristics of the generator rotor and the hydro-turbine runner during the load rejection [24]. The innovations of this study lie in three main aspects: (1) a new coupling method is proposed, which adds HGSs, a hydro-turbine characteristic curve, and a PID governor to the HGS model; (2) the vibration characteristics of HGSS in SLIP are studied, which have not yet been further investigated; (3) considering the hydraulic-mechanical-electric coupling vibration source, the influences of different HMEPs on the vibration characteristics of HGS in SLIP are studied.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
