Giovanni Bucci

Digital measurement station for power quality analysis in distributed environments

Today there is a wide application of different electronic apparatus that both produce electromagnetic disturbances on the supply power system and are sensitive to them. Power disturbances present on typical electric utility distribution systems degrade product quality, increase process downtime, and dissatisfy commercial customers. For these reasons, the monitoring of the quality of the supply networks has become an issue of international interest. To monitor power quality, in this paper, we propose a digital measurement station. Its main features are remote data transmission capability and reduced cost. It is a PC-based virtual instrument that offers the flexibility due to the high-level programming language, the familiar working environment of Windows, and the low cost of a widely used computer. The local area network or a modem card allows the measurement system to be controlled via a transmission control protocol/Internet protocol network, implementing in this way a distributed power quality evaluation system.

On-line digital measurement for the quality analysis of power systems under non-sinusoidal conditions

This paper presents a digital instrument for the power quality analysis in systems where voltage or current waveforms are non-sinusoidal. It is based on a C40 DSP and on a special high-speed data acquisition system. The analysis is performed by a recursive algorithm which allows the mutable system properties to be tracked. The paper also goes on to discuss the performance of an instrument prototype, both in terms of accuracy specifications and speed of measurement.

A New Flexible Optical Fiber Goniometer for Dynamic Angular Measurements: Application to Human Joint Movement Monitoring

The electronic measurement of the angle between two planes is generally performed by using the so-called electrogoniometers. The major drawback in using such devices is the presence of a fixed hinge that imposes a fixed center of rotation. This can cause problems when measuring the bending angle in some joints, such as Cardan or human joints, which have a variable rotation center. Based on an optical fiber, a sensor measuring the relative angle in a rotating joint has been developed. This joint makes use of the intensity modulation of a laser beam propagating in a single-mode optical fiber, due to the changes of its polarization status originated by the rotation of contiguous portions of the fiber, where controlled birefringence has been induced by the joint rotation. A prototype of this sensor has been developed with a range of the relative angle of 90deg , a resolution of less than 0.01deg, and a standard deviation of 0.1deg. The main advantages of this innovative sensor are lightness, flexibility, high speed of reaction, and high accuracy. This paper describes the development of the proposed sensor, with particular reference to the applications of human joint movement monitoring. Additionally, the equipment implemented for the test is illustrated, and results from laboratory tests are reported and discussed.

New ADC with piecewise linear characteristic: case study-implementation of a smart humidity sensor

In this paper, the architecture of a new analog-to-digital converter (ADC) with a piecewise linear characteristic (PLADC) is proposed. In this device, some discrete points of the characteristic can be modified to fit a requested profile. This converter facility can be utilized to gain remarkable advantages in a wide variety of applications, such as the implementation of a sensor linearization technique. In the paper the internal architecture of a two-stage 11-b flash PLADC prototype is briefly described. A representative demonstrative application, namely, the implementation of a linear digital humidity sensor, is discussed showing the effectiveness and usefulness of this device. The problem of the characterization of this converter is also discussed, reporting some remarks about the implemented solutions.

A multi-DSP based instrument on a VXI C-size module for real-time measurements

In this paper the design and implementation of a high-performance measuring instrument based on multiple digital signal processors (DSPs) is discussed. This system can embody a number of special signal processing and analog I/O modules, specifically designed to obtain the flexibility and scalability to meet the needs of real-time measurement applications. It has been mounted on a prototyping card and interfaced with the VXLbus backplane. Some issues related to the hardware and software design are discussed. A first application, namely the on-line spectral measurement of two input signals, e.g. voltage and current in a power circuit is discussed, reporting the first experimental results.

A distributed measurement architecture for industrial applications

In this paper, a distributed digital measurement architecture for industrial applications is proposed. The architecture is arranged on three hierarchical communication levels: the fieldbus, the intranet, and the Internet. Particular attention has been paid to the lower level, the field level, implemented using a low-priced smart front-end. It is based on the H8/3048F Hitachi microcontroller and embodies a fieldbus interface (I/F). The same board can be linked to a VXIbus controller by means of a suitable register-based interface. The proposed network can embody a number of analog signal conditioning circuits, processor, and communication capabilities, to meet the industrial needs. We propose two applications of this distributed measurement architecture: the monitoring of power quality in an electrical distribution network and the management of a water distribution system. Experimental results showing the system performance are also included in the paper.

Numerical method for transit time measurement in ultrasonic sensor applications

In this paper, the implementation of a novel algorithm for the measurement of the transit time is reported. It has been applied to implement a smart, ultrasonic sensor for the fluid level measurement on a tank by processing the detected signal. A prototype of an on-line operating device, assembled to demonstrate the performance of the algorithm, is also described. Simulation tests have been carried out to investigate the algorithm performance, and we report on the results obtained. In addition, the results obtained during the field testing and application of the developed sensor are reported.

Real-time transputter-based measurement apparatus: Performance testing

The authors deal with transputter-based equipment used in online indirect measurements on induction motors, by using an estimation algorithm performed in real-time. Starting with a brief description of the actual equipment, some considerations relating to the multiprocessor architecture are reported to point out hardware and software solutions adopted to fit real-time requirements. The dynamic behavior of the measurement station is discussed to highlight the overall equipment performance in terms of the achievable accuracy and execution speed. Some experimental results concerning the working operations of an actual induction motor fed by an inverter are included.<<ETX>>

Low cost smart power metering

Modern trends, including increased electricity requirements and improvements in grid management technologies, are causing the electric industry and regulators to review how the grid is achieved. With this aim, in this paper a low cost solution for the real-time energy management in a smart grid, is presented. It provides several smart meters, which act as slaves, that continuously monitor connected loads communicating with a data aggregator via CAN bus. Through the implemented web server the users can remotely control their consumption using a web browser. To prevent external attacks, a low computational cost protection software, based on Message Authentication Code (MAC), has been implemented. The paper illustrates the hardware architecture, discusses the adopted software solutions, and is completed with an example of energy monitoring for a generic household thanks the web server.

Embedded Power and Energy Measurement System Based on an Analog Multiplier

This paper deals with the development of an analog electronic wattmeter based on a high-accuracy electronic four-quadrant multiplier and appropriate amplifying and averaging circuits. The proposed instrument presents a simple design and is constructed using commercially available components. Its main advantage is that it can be integrated with the signal conditioning circuit, obtaining low cost, high resolution, and reduced dimensions. It can measure in circuits with very low power factors and nonsinusoidal waveforms. The implemented prototype is a portable laboratory instrument, integrated with a digital system capable of processing the signals, and displaying the main parameters of both electric power and energy. It has been designed to easily integrate the main blocks in that either industrial or civil equipment requiring the power measurement for monitoring or control purposes. A Fluke 6100A power standard is used to calibrate the wattmeter over a wide range of current magnitudes and widths and at power factors down to 0.02; several results are reported and discussed.