Automated Anomaly Detection in Distribution Grids Using uPMU Measurements

The impact of Phasor Measurement Units (PMUs) for providing situational awareness to transmission system operators \ has been widely documented. Micro-PMUs (uPMUs) \ are an emerging sensing technology that can provide similar \ benefits to Distribution System Operators (DSOs), enabling a \ level of visibility into the distribution grid that was previously \ unattainable. In order to support the deployment of these \ high resolution sensors, the automation of data analysis and \ prioritizing communication to the DSO becomes crucial. In this \ paper, we explore the use of uPMUs to detect anomalies on \ the distribution grid. Our methodology is motivated by growing \ concern about failures and attacks to distribution automation \ equipment. The effectiveness of our approach is demonstrated \ through both real and simulated data

Temporal variations of disinfection byproduct precursors in wildfire detritus

The Rim Fire ignited on August 17, 2013 and became the third largest wildfire in California history. The fire consumed 104,131 ha of forested watersheds that were the drinking water source for 2.6 million residents in the San Francisco Bay area. To understand temporal variations in dissolved organic matter (DOM) after the wildfire and its potential impacts on disinfection byproduct (DBP) formation in source water supply, we collected the 0-5 cm ash/soil layer with surface deposits of white ash (high burn severity) and black ash (moderate burn severity) within the Rim Fire perimeter in Oct 2013 (pre-rainfall) for five sequential extractions, and in Dec 2013 (∼87 mm cumulative precipitation) and Aug 2014 (∼617 mm cumulative precipitation) for a single water extraction. Water-extractable DOM was characterized by absorption and fluorescence spectroscopy and DBP formation tests. Both increasing cumulative precipitation in the field or number of extractions in the lab resulted in a significant decrease in specific conductivity, dissolved organic carbon, and DBP formation potential, but an increase in DOM aromaticity (reflected by specific UV absorbance). However, the lab sequential leaching failed to capture the increase of the NOx(-)-N/NH4(+)-N ratio and the decrease in pH and dissolved organic carbon/nitrogen ratio of ash/soil extracts from Oct 2013 to Aug 2014. Increasing cumulative precipitation, inferring an increase in leaching after fire, led to an increase in DOM reactivity to form trihalomethanes, haloacetic acids, and chloral hydrate, but not for haloketones, haloacetonitrile, or N-nitrosodimethylamine, which were more related to the original burn severity. This study highlights that fire-affected DBP precursors for different DBP species have distinct temporal variation possibly due to their various sensitivity to biogeochemical alterations

Micro-Synchrophasors: A Promising New Measurement Technology for the AC Grid

Large amounts of distributed generation (DG), especially solar, and electric vehicles may cause technical problems related to power quality, safety and reliability on electric distribution circuits. These impacts are not yet well understood. Early evidence suggests that significant infrastructure upgrades and operational changes in utility distribution systems may be required as DG penetration levels reach a critical threshold. New empirical information gathered from the field is needed to better define these requirements and the potential need for new technology developments. Data from distribution circuits must be collected and analyzed at higher resolution and with greater specificity so that the effects of distributed resources can be better understood and mitigated if necessary

Micro-Synchrophasors for Distribution Systems

This paper describes a research project to develop a network of high-precision phasor measurement units, termed micro-synchrophasors or μPMUs, and explore the applications of μPMU data for electric power distribution systems

Micro-Synchrophasors for Distribution Systems

This paper describes a research project to develop a network of high-precision phasor measurement units, termed micro-synchrophasors or μPMUs, and explore the applications of μPMU data for electric power distribution systems

Micro-synchrophasors for distribution systems

This paper describes a research project to develop a network of high-precision phasor measurement units, termed micro-synchrophasors or μPMUs, and explore the applications of μPMU data for electric power distribution systems

Power quality aspects of smart grids

Godkänd; 2010; 20100624 (matbol

Power quality aspects of smart grids

Godkänd; 2010; 20100624 (matbol

Online Thevenin Parameter Tracking Using Synchrophasor Data

There is significant interest in smart grid analytics based on phasor measurement data. One application is estima- tion of the Thevenin equivalent model of the grid from local measurements. In this paper, we propose methods using phasor measurement data to track Thevenin parameters at substations delivering power to both an unbalanced and balanced feeder. We show that for an unbalanced grid, it is possible to estimate the Thevenin parameters at each instant of time using only instantaneous phasor measurements. For balanced grids, we propose a method that is well-suited for online applications when the data is highly temporally-correlated over a short window of time. The effectiveness of the two methods is tested via simulation for two use-cases, one for monitoring voltage stability and the other for identifying cyber attackers performing "reconnaissance" in a distribution substation