This paper presents solutions for the development of test procedures that require remote control of instrumentation through the network. At first, a brief critical summary of some existing technologies is reported and commented. Then, an... more
This paper presents solutions for the development of test procedures that require remote control of instrumentation through the network. At first, a brief critical summary of some existing technologies is reported and commented. Then, an architecture based on a multiserver-multiclient paradigm is described. The architecture provides instrumentation management in a device-independent manner, fast development of user applications and supports different
E-learning is the one possible evolution of traditional teaching techniques and is becoming a mature technology. Several commercial suites are available to author multimedia courses either to be distributed in physical form (e.g. on CD or... more
E-learning is the one possible evolution of traditional teaching techniques and is becoming a mature technology. Several commercial suites are available to author multimedia courses either to be distributed in physical form (e.g. on CD or DVD) or to be used on-line. However the application of these suites to the instrumentation and measurement courses and in general to courses that
The knowledge of the distribution system state is required to operate management and control issues, such as energy dispatching and protection coordination. The authors have proposed a novel procedure for harmonic source estimation, based... more
The knowledge of the distribution system state is required to operate management and control issues, such as energy dispatching and protection coordination. The authors have proposed a novel procedure for harmonic source estimation, based on a Bayesian approach, aimed at giving distribution network operators information about the presence of harmonic producing loads, along with a key indication about the reliability
ABSTRACT Distribution systems require ad hoc estimators, distribution system state estimation (DSSE) techniques, to acquire knowledge about the system status. An incorrect evaluation of the accuracy of the DSSE creates decision risks in... more
ABSTRACT Distribution systems require ad hoc estimators, distribution system state estimation (DSSE) techniques, to acquire knowledge about the system status. An incorrect evaluation of the accuracy of the DSSE creates decision risks in network management. The possible variations in the network parameter values and the decays of the metrological characteristics of the measurement system elements are uncertainty sources very often not considered. Considering these possible lacks of accuracy, this paper focuses on the robustness of distributed measurement systems aimed to obtain accurate DSSE results. The problem of the proper assessment of the accuracy of the DSSE results obtained through a weighted least squares (WLS) approach is faced. A method capable of including different uncertainty sources in the uncertainty estimation of the WLS approach is presented. Furthermore, this paper proposes an optimal meter placement algorithm robust with respect to possible malfunctions in measurement system components. The results obtained on a portion of an Italian distribution network, along with their accuracy, are presented and discussed.
ABSTRACT Energy management systems for the operation of distributed energy resources, distribution storage devices, and responsive loads will be embedded in distribution management systems (DMSs) as advanced functions that rely on... more
ABSTRACT Energy management systems for the operation of distributed energy resources, distribution storage devices, and responsive loads will be embedded in distribution management systems (DMSs) as advanced functions that rely on accurate input data and fast communication signals. For a proper DMS design, the impact of the state estimation uncertainties and of the communication system delays should be evaluated. The paper presents an integrated software package for the cyber-physical simulation of DMS taking into account the accuracy of state estimation and measurements. The effectiveness of a wireless Wi-Max communication system has been tested on the rural Italian representative network produced by the research project ATLANTIDE. Results proved the need of cosimulation packages in modern distribution systems.
ABSTRACT This paper presents a new approach to the distribution system state estimation in wide-area networks. The main goal of this paper is to present a two-step procedure designed to accurately estimate the status of a large-scale... more
ABSTRACT This paper presents a new approach to the distribution system state estimation in wide-area networks. The main goal of this paper is to present a two-step procedure designed to accurately estimate the status of a large-scale distribution network, relying on a distributed measurement system in a multiarea framework. First of all, the network is divided into subareas, according to geographical and/or topological constraints and depending on the available measurement system. Then, in the first step of the estimation process, for each area, a dedicated estimator is used, exploiting all the measurement devices available on the field. In the second step, data provided by local estimators are further processed to refine the knowledge on the operating conditions of the network. To improve the accuracy of the estimation results, correlation arising in the first step estimations has to be suitably evaluated and considered during the second step. Performed analysis shows that existing correlations can be included in the estimation process with very low data exchange among areas, thus involving minimum communication costs. Both first and second steps can be performed in a decentralized way and with parallel processing, thus leading to reduced overall execution times. Test results, obtained on the 123-bus IEEE test network and proving the goodness of the proposed method, are presented and discussed.
ABSTRACT The distribution grid is the infrastructure that transports electrical energy generated by large plants that are long distances away to the final user. A typical distribution grid consists of High-to-Medium Voltage (HV/MV)... more
ABSTRACT The distribution grid is the infrastructure that transports electrical energy generated by large plants that are long distances away to the final user. A typical distribution grid consists of High-to-Medium Voltage (HV/MV) transformation centers; the MV grid; Medium-to-Low Voltage (MV/LV) transformation centers; and the LV grid, both three-phase and single-phase. Residential and commercial customers are mainly connected to the LV, while large industrial facilities are connected to the MV.
ABSTRACT Smart Grid (SG) is an expression that has diffused worldwide. However, the meaning of this expression is not commonly shared, since there is not yet a totally defined or accepted idea of smartness. What is commonly recognized is... more
ABSTRACT Smart Grid (SG) is an expression that has diffused worldwide. However, the meaning of this expression is not commonly shared, since there is not yet a totally defined or accepted idea of smartness. What is commonly recognized is that significant changes are occurring in electric systems, and traditional management and protection schemes will not be suitable for next generation electric grids [1]. This paper discusses some of the challenges and the opportunities related to the measurement of energy in modern distribution grids. In particular, the possibility to estimate energy flows in the network branches is explored, by focusing on the importance of a proper choice of the components of the distributed measurement system, mainly in terms of typology, metrological characteristics, and number and position of the measurement devices.
ABSTRACT For future active distribution grids the design of the measurement infrastructure is a critical element for an effective control and operation. The use of accurate and real-time measurements from heterogeneous existing and... more
ABSTRACT For future active distribution grids the design of the measurement infrastructure is a critical element for an effective control and operation. The use of accurate and real-time measurements from heterogeneous existing and emerging metering devices offers a new paradigm for the distribution grid monitoring system. In a previous work, the authors proposed a meter placement procedure that allows for an optimization of the metering infrastructure for distribution system state estimation (DSSE) satisfying given estimation error bounds, while keeping into account different accuracies and costs of Phasor Measurement Units (PMUs) and smart metering devices as well as different network configurations of the future active distribution grids. In this paper the investigations are extended to the optimal meter placement by considering the characteristics variable over time of loads and generation from renewable sources. The DSSE based on the resulting metering infrastructure is then able to achieve the given accuracy constraint under the time varying and uncertain behavior of the loads and renewable generation.
ABSTRACT In this paper solutions aiming at achieving a Phasor Measurement Unit that is simultaneously compliant with both M and P classes of the standard IEEE C37.118.1, for synchrophasor estimation at a fixed reporting rate, are... more
ABSTRACT In this paper solutions aiming at achieving a Phasor Measurement Unit that is simultaneously compliant with both M and P classes of the standard IEEE C37.118.1, for synchrophasor estimation at a fixed reporting rate, are presented. In particular, a new version of the Taylor-Fourier Transform (TFT) based adaptive algorithm previously proposed by the authors is used for synchrophasor estimation, while frequency and Rate of Change of Frequency (ROCOF) are estimated using the higher derivatives outputs of the adaptive TFT. Frequency estimation feedback is used to tune the algorithm and achieve better performance. The proposed approaches are validated by means of simulations in all the static and dynamic conditions defined in the Standard.
This work presents an approach to the detection of local features in network traffic, based on the analysis of short-time maximal rate envelopes, also called statistical arrival curves. In the proposed method, the time series representing... more
This work presents an approach to the detection of local features in network traffic, based on the analysis of short-time maximal rate envelopes, also called statistical arrival curves. In the proposed method, the time series representing a traffic trace is divided into non-overlapping segments, which are further divided into smaller blocks. The maximal rate envelope is estimated for each block
Continuous monitoring of performances becomes necessary to detect critical situations in the radio interface of digital wireless telephone networks. This paper presents a measurement tool that analyzes TCP-level packet traffic and detects... more
Continuous monitoring of performances becomes necessary to detect critical situations in the radio interface of digital wireless telephone networks. This paper presents a measurement tool that analyzes TCP-level packet traffic and detects the effects of variations in the radio channel conditions of a mobile network. The analysis algorithm considers the energies of wavelet coefficients of the aggregated traffic process at
ABSTRACT Deregulation and privatization actions are creating new problems of control, management and reliability, because of new players and new technologies spreading in distribution systems. Such new scenarios require more comprehensive... more
ABSTRACT Deregulation and privatization actions are creating new problems of control, management and reliability, because of new players and new technologies spreading in distribution systems. Such new scenarios require more comprehensive and accurate knowledge of the system to make control actions efficient and reliable. In particular, attention must be paid to phase angles estimation to avoid critical situations. In this context, the use of phasor measurement units (PMUs) looks promising. This paper presents an efficient branch-current-based distribution systems state estimation. The estimator allows synchronized phasor measurements provided by PMUs to be included. In addition, the branch current state model is extended so that the knowledge of the voltage profile is significantly improved. The estimator is expressed both in polar and rectangular coordinates and a comparison between the obtainable accuracy and computational efficiency is presented. Furthermore, the possibility to treat radial and weakly meshed topology, also in presence of dispersed generation, is analyzed. The results obtained on different distribution networks are presented and discussed.
