1,721,024 research outputs found
Measurement Platform for Latency Characterization of Wide Area Monitoring, Protection and Control Systems
Full text linkWide area monitoring, protection and control (WAMPAC) systems have emerged as a critical technology to improve the reliability, resilience, and stability of modern power grids. They are based on phasor measurement unit (PMU) technology and synchronized monitoring on a wide area. Since these systems are required to make rapid decisions and control actions on the grid, they are characterized by stringent time constraints. For this reason, the latency of WAMPAC systems needs to be appropriately assessed. Following this necessity, this article presents the design and implementation of a measurement platform that allows latency characterization of different types of WAMPAC systems in several operating conditions. The proposed WAMPAC Characterizer has been metrologically characterized through a WAMPAC Emulator and then used to measure the latency of a WAMPAC system based on an open-source platform frequently used by transmission system operators (TSOs) for the implementation of their PMU-based wide area systems
Characterization of Matrix Profile Technique for Enhanced Detection of Events in Sampled Values Data Streams
Full text linkIn the architecture described by IEC 61850 standards, merging units (MUs) and stand-alone MUs (SAMUs) are the initial elements in the measurement chain, with the main function of acquiring analog voltage and current signals, digitizing the samples and transmitting them to intelligent electronic devices (IEDs) for the evaluation of metrics of interest. Since they produce digital data, it is therefore possible to design extensions of their functionality that include data processing and the ability to identify events in the power grids. In this context, this article characterizes an event identification function to be implemented in MUs, based on the matrix profile (MP) technique and considering the Python library Stumpy. A comprehensive characterization of the MP technique is presented to evaluate its effectiveness for identifying discords in signals such as rapid events or voltage dips. The behavior of the MP technique is analyzed under different signal conditions and configurations, including variations in the number of samples per cycle and different window lengths. Noisy signals and challenging conditions such as overlapping events are considered. The MP performance is compared with other techniques used for discord detection in time series. The results obtained prove its robustness to noise and confirm its ease of use, needing only one parameter to operate
Low-cost implementation and characterization of an active phasor data concentrator
Full text linkThe main components of an advanced measurement system based on synchrophasor technology for the monitoring of power systems are the phasor measurement unit (PMU), which represents the ‘sensor’, and the phasor data concentrator (PDC), which collects the data forwarded by PMUs installed on the field. For the purpose of extending the benefit of synchrophasor technology from transmission grids to distribution networks, different projects are seeking to use low-cost platforms to design devices with PMU functionalities. In this perspective, in order to achieve a complete synchrophasor-based measurement architecture based on low-cost technologies, this work presents a PDC design based on a low-cost platform. Despite the simplicity of the considered hardware, advanced PDC functionalities and innovative control logics are implemented in the prototype. The proposed device is characterised by several experimental tests aimed at assessing its performance in terms of both time synchronisation and capability of managing several PMU data streams. The feasibility of some additional functionalities and control logics is evaluated in the context of different possible scenarios
Impact of the Model on the Accuracy of Synchrophasor Measurement
No full textPhasor measurement units (PMUs) are becoming one of the key issues of power network monitoring. They have to be able to perform accurate estimations of quantities of interest either under steady-state or transient conditions. Among all the sources which may contribute to the uncertainty introduced by PMUs, this paper analyzes the impact of the phasor estimation models on the accuracy of these devices, focuses on algorithms proposed in the literature for the estimation of dynamic phasors, and studies their performances under several different conditions
A monitoring system based on phasor measurement units with variable reporting rates
Full text linkClassical Wide-Area Monitoring Systems (WAMSs) are characterized by a hierarchical architecture, which is composed of Phasor Measurement Units (PMUs) and different levels of Phasor Data Concentrators (PDCs). The WAMS, based on synchrophasor technology, was originally designed for transmission systems; nevertheless, with the development of the smart grid paradigm, the benefits of this technology are being extended to distribution networks. Normally, PMUs send measurement data at a high and constant reporting rate to guarantee the monitoring of dynamic events in an electric transmission network. However, typical communication systems that are expected to be used by distribution system operators are generally shared and/or public. In this case, the bandwidth available among PMUs and PDCs, or among the PDCs and the control center, is strictly dependent on the type of communication channel that is used and on the level of network traffic. In this context, a new transmission logic for the transfer of data between PMUs and PDCs, based on the knowledge of the ongoing conditions of the electric grid, can be implemented. The strategy proposed in this paper is to increase the measurement reporting rate only when the electric system changes from a steady-state condition to a dynamic and potentially unsafe one, without modifying the overall accuracy of the PMU measurement process. The risk of losing important information related to a dynamic event is mitigated by sending to the PDC (after the event detection) measurements relating to the pre-trigger time interval in a burst of data packets that allow insight into the signal evolution
PMU Measurement Accuracy Awareness Provided by Power Quality Indices
No full textPhasor measurement units (PMUs) are measurement devices capable of monitoring voltage and current phasors, frequency and rate of change of frequency considering an absolute time reference for phase angle evaluation. The absolute reference is provided by coordinated universal time (UTC) through global navigation satellite system signals and distributed to PMUs through appropriate protocols or dedicated receivers. The quality level of time synchronization is directly related to the quality of the measurement as it affects the phase-angle evaluation. This relationship is taken into account and communicated through dedicated fields in the data packets containing the PMU measurements. However, other factors can affect the quality of the measurements, such as changes in the signal or the presence of disturbances. These influencing factors, or, in general, the operating conditions in which the PMUs are immersed while providing measurements, are typically not evaluated in real-time. For this purpose, a real-time estimation of the PMU measurement conditions is presented in this paper. Such estimation is carried out on the basis of the information provided by power quality indices. The goal is to accompany measured quantities with information on the measurement quality that can be helpful for proper use of the collected measurements
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