An Advanced Teaching Lab for the Setting up of an Islanded Production Unit

The present paper addre teaching lab consisting of setting up an is unit. This teaching lab takes place in the ve master level for students in electrical engin specialization. The purpose of this teaching knowledge learned in different areas such as control, electrical machines and networks, a of them in practice. The present paper des different steps followed by the student to production unit. Index Terms—Teaching Laboratory, Isl

Eigenvalues Analysis Applied to the Stability Study of a Variable Speed Pump Turbine Unit

This paper presents an eigenvalues analysis method for an induction machine model based on phase variables a, b, c. This approach is validated by comparison with ad, q approach and applied to a variable speed pump-turbine unit using a simplified model of the converters. The proposed approach permits the study and analysis of the interaction between mechanical, electric and regulation parts of the system. Index Terms—control systems, numerical simulation, induction motors, AC-DC power converters, pumps, ..

Unstable Operation of Francis Pump-Turbine at Runaway: Rigid and Elastic Water Column Oscillation Modes

This paper presents a numerical simulation study of the transient behavior of a 2x340MW pump-turbine power plant, where the results show an unstable behavior at runaway. First, the modeling of hydraulic components based on equivalent schemes is presented. Then, the 2 pump-turbine test case is presented. The transient behavior of the power plant is simulated for a case of emergency shutdown with servomotor failure on Unit 1. Unstable operation at runaway with a period of 15 seconds is properly simulated using a 1-dimensional approach. The simulation results points out a switch after 200 seconds of the unstable behavior between a period of oscillations initially of 15 seconds to a period of oscillation of 2.16 seconds corresponding to the hydraulic circuit first natural period. The pressure fluctuations related to both the rigid and elastic water column mode are presented for oscillation mode characterization. This phenomenon is described as a switch between a rigid and an elastic water column oscillation mode. The influence of the rotating inertia on the switch phenomenon is investigated through a parametric study

Increasing Wind Power Penetration in Autonomous Power Systems through No-Flow Operation of Pelton Turbines

The integration of wind power in power systems results in a reduction in greenhouse gas emissions. Thus, it has a positive environmental impact. However, the operation of these power systems becomes increasingly complex, owing mainly to random behaviour of the wind

HIL Simulation of a Mixed Islanded Power Network with External DSP Regulator

The present paper deals with the development of a modular, flexible and structured block to block approach for the study of regulators by implementing the different blocks on a DSP (digital signal processor). The proposed low-cost approach has been applied and validated by the implementation of an industrial regulator in a real time hardware-in-the-loop simulation of a mixed islanded power network including precise models of the hydraulic system. The studied network is constituted of three different types of electrical power ..

Optimization of the Start-up Time of a Variable Speed Pump-Turbine Unit in Pumping Mode

This paper presents the start-up and synchronization procedures of large variable- speed pump-turbine units in pumping mode. These procedures applied to a doubly-fed induction motor-generator with three-level voltage source inverters VSI cascade in the rotor side, can be achieved without any supplementary equipment, for instance without an autotransformer connected to the rotor. The control strategy used in the start-up procedure and based on a stator flux oriented control is summarized as well as different steps in ..

Influence of the vortex rope location of a Francis Turbine on the hydraulic system stability

Hydroelectric power plants are known for their ability to cover variations of the consumption in electrical power networks. In order to follow this changing demand, hydraulic machines are subject to off-design operation. In that case, the swirling flow leaving the runner of a Francis turbine may act under given conditions as an excitation source for the whole hydraulic system. In high load operating conditions, vortex rope behaves as an internal energy source which leads to the self excitation of the system. The aim of this paper is to identify the influence of the full load excitation source location with respect to the eigenmodes shapes on the system stability. For this, a new eigenanalysis tool, based on eigenvalues and eigenvectors computation of the nonlinear set of differential equations in SIMSEN, has been developed. First the modal analysis method and linearization of the set of the nonlinear differential equations are fully described. Then, nonlinear hydro-acoustic models of hydraulic components based on electrical equivalent schemes are presented and linearized. Finally, a hydro-acoustic SIMSEN model of a simple hydraulic power plant, is used to apply the modal analysis and to show the influence of the turbine location on system stability. Through this case study, it brings out that modeling of the pipe viscoelastic damping is decisive to find out stability limits and unstable eigenfrequencies

Forced response analysis of hydroelectric systems

At off-design operating points, Francis turbines develop cavitation vortex rope in the draft tube which may interact with the hydraulic system. Risk resonance assessment by means of eigenmodes computation of the system is usually performed. However, the system response to the excitation source induced by the cavitation vortex rope is not predicted in terms of amplitudes and phase. Only eigenmodes shapes with related frequencies and dampings can be predicted. Besides this modal analysis, the risk resonance assessment can be completed by a forced response analysis. This method allows identifying the contribution of each eigenmode into the system response which depends on the system boundary conditions and the excitation source location. In this paper, a forced response analysis of a Francis turbine hydroelectric power plant including hydraulic system, rotating train, electrical system and control devices is performed. First, the general methodology of the forced response analysis is presented and validated with time domain simulations. Then, analysis of electrical, hydraulic and hydroelectric systems are performed and compared to analyse the influence of control structures on pressure fluctuations induced by cavitation vortex rope

A System for Wireless Power Transfer of Micro-Systems In-Vivo Implantable in Freely Moving Animals

A system for wireless power transfer of micro-systems in-vivo implantable in small animals is presented. The described solution uses a servo-controlled transmitter moved under the animal moving space. The solution minimizes the power irradiation while enabling animal speeds up to 30 cm/s. An x-y movable magnetic coil transmits the required power with a level able to keep constant the received energy. A permanent magnet on board of the implantable micro-system and an array of magnetic sensors form a coil tracking system capable of an alignment accuracy as good as 1 cm. The power is transferred over the optimized remote powering link at 13.56 MHz. The received ac signal is converted to dc voltage with a passive full-wave integrated rectifier and the voltage regulator supplies 1.8 V for the implantable sensor system. Experimental measurement on a complete prototype verifies the system performance