Laurent Fabre

TinyNode: a comprehensive platform for wireless sensor network applications

We introduce the TinyNode platform for wireless sensor networks. Supporting both research and industrial deployments, the platform offers communication ranges that exceed current platforms by a factor of 3 to 5, while consuming similar energy. It comes with a rich, practical set of hardware extensions and full TinyOS support. We describe the design choices of the TinyNode, the accompanying hardware modules, and the MAC layer implementation

High-Speed Power System Transient Stability Simulation Using Highly Dedicated Hardware

This paper presents a fully analog demonstrator based on power system emulation for high-speed power system stability analysis. A benchmark using a fixed two-machine topology has been implemented. The characteristics of the emulated components (i.e., generators and transmission lines) are reprogrammable and short circuits can be emulated at different distances from the generator. This first realization is limited to transient stability analysis, as the main focus during design was put on computation speed. Indeed, the emulated phenomena are 10 000 times faster than real time. Moreover the authors aim to emphasize that such highly dedicated computation architectures are not only competitive in terms of speed, but also in terms of modularity.

High-speed, mixed-signal emulation for power system dynamic analysis

This paper presents two different demonstrators of electronic hardware platforms, dedicated to power system emulation. They use DC emulation approaches of an AC power system. Both demonstrators focus on the speeding-up of the temporal analysis of a power system. The first demonstrator proves the feasibility of such programmable hardware. Moreover, comparison with a reference numerical simulator is used to confirm the accuracy of obtained results. The effect of analog-to-digital (A/D) and digital-to-analog (D/A) electronic conversion on the accuracy is also analyzed. The second hardware platform aims to improve generator and load models. At the same time, it also increases the flexibility of the hardware demonstrator platform.

An Ultra-High Speed Emulator Dedicated to Power System Dynamics Computation Based on a Mixed-Signal Hardware Platform

This paper presents an ultra-high speed hardware platform dedicated to power system dynamic (small signal) and transient (large signal) stability. It is based on an intrinsic parallel architecture which contains hybrid mixed-signal (analog and digital) circuits. For a given model, this architecture overcomes the speed of the numerical simulators by means of the so-called emulation approach. Indeed, the emulation speed does not depend on the power system size. This approach is nevertheless not competing against high-performance numerical simulators in term of accuracy and model complexity. It targets to complement the numerical simulators with the advantage of speed, portability, low cost and autonomous functioning. The proof of concept is a flexible and modular 96-node hardware platform. It is based on a reconfigurable array of power system buses called Field Programmable Power Network System (FPPNS). Details on this hardware are given. Two benchmark topologies with, respectively, 17 nodes and 57 nodes are provided. Comparisons with a digital simulator are done in terms of speed and accuracy. The calibration of the system is explained and different applications are proposed and discussed. The promising results of this hardware platform show that the design of a fully integrated solution containing hundreds of power system buses can be achieved in order to provide a low cost solution.

Toward a Power System Emulation using Analog Microelectronics Solid State Circuits

An analog electronics emulation solution is investigated in order to assess the state of a power system facing dynamic phenomena such as the transient stability. Two approaches are studied: DC emulation and AC emulation. Both are intended to be integrated on VLSI submicron CMOS silicon technologies. This implementation has the advantages of presenting low cost, fast simulation time that is independent of the network size and the number of the generators connected to it, low power consumption and small size.

An ultra high-speed, mixed-signal emulator for solving power system dynamic equations

This paper focuses on a new pipelined processing unit architecture dedicated to mixed-signal power system emulation. Prior research in this field has proven that analog emulation overcomes the speed limits of numerical simulators with reliable accuracy. Then, a new concept based on field programmable power network system (FPPNS) has been developed in order to gain in term of flexibility. It is based on a hybrid architecture where grid equations are solved analogically and generator and load equations are solved digitally. A first platform based on a developed application specific integrated circuit has validated the concept with a 16-node topology. The present work aims to extend the size of the emulation hardware (up to 100 nodes) as well as to increase the speed. Therefore the digital equations are solved on an embedded FPGA containing four parallel pipelined processing unit which are interfaced to the analog emulator. Speed results are provided and compared with a reference numerical simulator.

A mixed-signal platform dedicated to power system dynamic computation

This paper further examines the use of mixed-signal circuits for power system emulation. It has already been proven that analog emulation overcomes the speed limits of numerical simulators by means of a simple fixed-topology prototype. In order to enhance the modularity and the size of the emulated power system a dedicated platform based on a field programmable power network system (FPPNS) has been developed. This platform contains an application specific integrated circuit as main building block. Details on the designed hardware are given in this paper. Furthermore the emulator is validated comparing its emulation results with numerical reference simulations. The promising results of this platform show that the design of a fully integrated solution containing an array of 100 atoms can be started.

Microelectronic, high-speed data processing calculators for power system analysis: Comparison

This paper highlights the increasing need for faster than real-time simulators of the electric power system and shows that microelectronic emulation is a very promising solution to overcoming speed problems of current numerical simulators. Research is focused on two different emulation approaches. Both of them are detailed in this paper and their electronic implementation is shown. Furthermore, the two approaches are compared and their final capabilities are depicted. By doing so, the paper shows that the two approaches are not competing; each one has its own advantages.

A mixed-platform framework for Dynamic Stability Assessment

This paper describes a mixed-platform framework dedicated to Dynamic Stability Assessment of power systems. DSA refers to tools capable of characterizing the dynamic stability of the system. Time domain simulation is critical for DSA analysis and is done by algorithms known as TD engines. In this work, operations are shared between a software platform and a hardware one. TD simulation is handled by a dedicated mixed-signal electronics implementation. Data flow control, user interfacing, configuration, result post-processing and other auxiliary operations are realized in software. This architecture combines the flexibility of the software with the high-performance of dedicated hardware. Results of a multi-contingency analysis and a critical clearing time determination analysis for sample test cases are presented. It is demonstrated that an increase in speed of almost three orders of magnitude can be achieved, compared to single-platform solutions.

EXPERIMENTAL INVESTIGATION OF FLOW INSTABILITIES AND ROTATING STALL IN A HIGH-ENERGY CENTRIFUGAL PUMP STAGE

In centrifugal pumps, the interaction between the rotating impeller and the stationary diffuser generates specific pressure fluctuation patterns. When the pump is operated at off design conditions, these pressure fluctuations increase. The resulting rise of mechanical vibration levels may negatively affect the operational performance and the life span of mechanical components. This paper presents detailed pressure fluctuation measurements performed in a high speed centrifugal pump stage at full scale at various operating conditions. The impeller and stationary part (diffuser, exit chamber) of the pump stage have been equipped with piezo-resistive miniature pressure sensors. The measured data in the impeller have been acquired using a newly developed onboard data acquisition system, designed for rotational speeds up to 6000 rpm. The measurements have been performed synchronously in the rotating and stationary domains. The analysis of pressure fluctuations at the impeller blade trailing edge, which had significantly larger amplitudes as the pressure fluctuations in the stationary domain, allowed the detection and exploration of stalled channels in the vaned diffuser. This stall may be stationary or rotating with different rotational speeds and number of stalled channels, depending on the relative flow rate and the rotational speed of the pump. The stall yields pressure fluctuations at frequencies which are multiples of the rotational speed of the impeller and generates additional sources of mechanical excitation.