To address the challenges of wind–solar output correlation, renewable-output uncertainty, transient stability, and economic optimization, this paper proposes a transient stability-constrained optimal power flow (TSCOPF) model considering wind&n...
Traditional transient stability-constrained optimal power flow (TSCOPF) methods rely on solving complex nonlinear differential equations, resulting in high computational demands and lengthy processing times. To address these issues, this paper propos...
The transient mechanism of dual-boundary dynamic opening in the inlet during stage transition of an integral solid rocket ramjet (ISRR) remains insufficiently understood. To address this issue, a combined approach involving numerical simulations and...
To better respond to the impact of power system-uncertain parameters on transient stability, a novel model named the parametric transient stability constrained optimal power flow (parametric TSCOPF) is proposed. It seeks the optimal control scheme of...
To address the issue of uncertainty in renewable energy and its impact on the safe and stable operation of power systems, this paper proposes a transient stability constrained optimal power flow (TSCOPF) calculation method that takes into account the...
To address the dependence of uncertainty analysis methods on assumed probability density functions of wind power output and the computational burden of time-domain simulations in transient stability-constrained optimal power flow (TSCOPF) problems, t...
Predicting the need for modeling and solutions is one of the largest difficulties in the electricity system. The static-constrained solution, which is not always powerful, is provided by the Gradient Method Power Flow (GMPF). Another benefit of using...
In the nozzle flapper servo valve, the transient flow force on the flapper is the fundamental reason that affects the pressure stability. The pressure pulsation in the pilot stage causes forced vibration of the flapper, and its deviation will directl...
The working condition of a centrifugal pump as a turbine (PAT) is often unsteady. The rotating speed of a PAT constantly varies as the flow and load change, resulting in transient hydrodynamic behaviors between different working conditions. During th...
Many of the recent projects for new transmission line have considered the high-voltage direct current (HVDC) system, owing to the many advantages of the direct current (DC) system. The most noteworthy advantage is that a cable can serve as a substitu...
The increasing penetration of non-synchronous, renewable energy in modern power systems displaces synchronous generation and affects transient stability. This is just one of the factors that has led to preventive curtailment of renewable energy sourc...
The presented article provides a comprehensive study on the stability analysis of earth-fill dams under rapid drawdown and transient flow conditions used to prepare stability analysis charts by conducting coupled finite-element numerical and analytic...
The optimization of the operation of power systems including steady state and dynamic constraints is efficiently solved by Transient Stability Constrained Optimal Power Flow (TSCOPF) models. TSCOPF studies extend well-known optimal power flow models...
25 August 2023
Baroclinic instability is one of the main mechanisms for the formation of synoptic scale systems. Previous studies examined the exponential growth of small perturbations for a stably stratified troposphere in the case of a constant meridional tempera...
Experimental and numerical investigations are conducted on a rotating disk from the perspective of convective heat transfer to understand the effect of heating on the stability of flow. A non-invasive approach with a thermal camera is employed to det...
The runaway oscillation process of the pump-turbine in a high head pumped-storage power plant is usually unstable. The root cause of its instability is still unclear. In this paper, its internal mechanism and the improvement method were studied in de...
To improve the transient operating stability of Francis turbines under flexible regulation conditions, this study investigates the effects of different speed-change modes on the internal flow structure and pressure pulsation characteristics of a high...
Super smart grids (SSGs) are a wide area transmission network that mainly uses renewable energy resources (RERs), contributing to the reduction of greenhouse gas (GHGs) emissions and supporting the power infrastructure of multiple countries. The SSGs...
The flow behavior inside a miniature centrifugal pump, under a periodic pulse flow rate, was studied by means of numerical simulation. For a given incoming periodic pulse flow with a sine wave, the performance of the centrifugal pump was investigated...
Centrifugal pumps as turbines (PATs) are widely used in chemical engineering for recycling the abundant energy from high-pressure fluid. The operation of PATs is significantly affected by their upstream conditions, which are not steady (i.e., with a...
The installation of battery energy storage systems (BESSs) with various shapes and capacities is increasing due to the continuously rising demand for renewable energy. To prepare for potential accidents, a study was conducted to select the optimal lo...
The stability and behavior of jet flows are critical in various engineering applications, yet many aspects remain insufficiently understood. Previous studies predominantly relied on modal methods to describe small perturbations on jet flow surfaces t...
The linear temporal stability of the Poiseuille flow through a rectangular duct is considered. The effect of the duct aspect ratio on the transient growth of disturbances, which causes the so-called subcritical laminar–turbulent transition, is...
A transient stability flow analysis is performed using the unsteady laminar boundary layer equations. The flow dynamics are studied via the Navier–Stokes equations. In the case of external spatially developing flow, the differential equations a...
This paper explores the possibility of using the Winter–Kennedy (WK) method for transient flow rate measurement in hydraulic turbines. Computational fluid dynamic (CFD) analysis of a numerical model of an axial turbine was carried out for accel...
In this paper, a novel meshless method for the transient modeling of subsurface flow in unsaturated soils was developed. A linearization process for the nonlinear Richards equation using the Gardner exponential model to analyze the transient flow in...
The accurate modeling and understanding of complex transient mixed pipe flows is crucial for the optimal design and safe and efficient operation in pipeline systems such as urban drainage systems. Currently, the predominant approach for modeling free...
In transient stability preventive control of power systems, time-domain simulation is computationally intensive. In addition, the initial operating feature data often contain abundant redundant and irrelevant information. These factors may adversely...
Current transient stability analysis of power systems with doubly fed induction generators (DFIGs) draws upon the assumption that nodal electromagnetic power equals to zero during the fault period. The omission of electromagnetic power degrades the f...
For a water diversion hydropower system with a flat ceiling tail tunnel with high elevation, during transient states with relatively low tail water levels, free-surface-pressurized flow inevitably appears and its transient characteristics have obviou...
Siphon vertical axial-flow pump systems are widely used in large-scale low-head pumping stations, irrigation and drainage projects, urban flood control, and water diversion engineering, where safe and stable operation is essential for hydraulic syste...
Total transfer capability (TTC) is a vital security indicator for power exchange among areas. It characterizes time-variants and transient stability dynamics, and thus is challenging to evaluate efficiently, which can jeopardize operational safety. A...
Multistage pumps are essential in emergency water supply, irrigation, and other systems undergoing unavoidable hydraulic transitions like pump startup and valve operations. These transitions cause rapid changes in impeller speed, flow rate, and press...
The start-up process of a siphon vertical axial-flow pump is accompanied by rapid internal-flow reconstruction, transient hydraulic loading and unsteady rotor response, which directly affect the operational stability of the pump system. In this study...
During load rejection in pumped-storage power stations, the rotational speed of the pump-turbine increases abruptly. The consequent structural deterioration of the internal flow induces high-amplitude hydraulic excitations, posing a serious threat to...
Frequent heat-source drift and environmental disturbances keep hydrogen compressors in a state of thermal non-equilibrium, where transient interactions between thermal transpiration and Poiseuille flows significantly influence system stability and sa...
Transient stability preventive control (TSPC), a method to efficiently withstand the severe contingencies in a power system, is mathematically a transient stability constrained optimal power flow (TSC-OPF) issue, attempting to maintain the economical...
Accurate water hammer calculations are crucial for hydraulic safety and unit stability in hydropower systems with free-surface tailrace tunnels. However, existing models often neglect hydraulic variations in free-surface sections, while the commonly...
Layered flows that are commonly observed in stratified turbulence are susceptible to the Taylor–Caulfield Instability. While the modal stability properties of layered shear flows have been examined, the non-modal growth of perturbations has not...
With the gradual operation of large-capacity HVDC transmission, HVDC), the characteristics of the “strong and weak communication” of the power grid are increasingly obvious. The power impact of the DC line after locking has a great impact...
This study examines the dynamic fluid behavior of a PWM-controlled Solenoid-Operated Gas Admission Valve (SOGAV) for large-bore CNG engines using 3D Computational Fluid Dynamics (CFD) simulations with dynamic mesh techniques. The research focuses on...
To address the escalating demand for power grid load regulation, pumped storage power stations must frequently switch between operational modes. As a key component of such stations, the pump turbine has seen extensive research on its steady-state flo...
Pump annular seals can cause fluid reaction forces that have great effects on the vibration characteristic and stability of a pump system. For this reason, it is important to study rotordynamic characteristics of annular seals. In this paper, a new t...
A non-modal transient disturbances growth in a stably stratified mixing layer flow is studied numerically. The model accounts for a density gradient within a shear region, implying a heavier layer at the bottom. Numerical analysis of non-modal stabil...
This paper deals with a mathematical modeling of flow stability of Newtonian and non-Newtonian fluids in the gap between two concentric cylinders, one of which rotates. A typical feature of the flow is the formation of a vortex flow, so-called Taylor...
This study investigates the transient behavior of a single-blade centrifugal pump under variable frequency speed regulation, with the objective of enhancing both pump efficiency and operational stability under variable frequency conditions. By integr...
Currently, the growing need for efficient refrigeration resources in the industrial sector has led to an increasing interest in finding technologies with a higher heat removal potential and better cooling performance. Along these lines, two-phase liq...
The addition of phase modulation function technology to thermal power units is one of the most effective measures to solve dynamic reactive power shortages in the construction process of new power systems. In this paper, the influence of the phase mo...
The internal flow in a vertical axial-flow pump is a complex unsteady three-dimensional viscous flow. An unstable flow often produces complex flow phenomena such as flow separation, vortices, and secondary reflux, which reduces the operating efficien...
To improve the energy conversion performance and long-term structural stability of stay vane mixed-flow chemical pumps used for industrial residual pressure recovery, this paper establishes a coupled numerical framework of computational fluid dynamic...
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