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Phasor measurement units have been installed on the power systems for grasping system static and dynamic behavior over wide area. Synchrophasor brings effective information of the power system disturbances such as the sudden supply and demand imbalance of the system. However, huge amount of synchrophasor data over the wide area power systems requires some techniques to extract the disturbances. In...
This paper discusses the application of PMU measurements in real-time estimation of transmission line power losses. Instead of directly computing the difference between sent and received power, the losses are estimated as separate components, calculated from line equations. On one hand, this provides more information about the operation of the line—active losses are split into Joule and corona losses...
In this paper two different methods to estimate the proximity of the system to the Maximum Loading Point (MLP) are proposed. They are compared with a specific method recently published that uses the Cubic Spline Extrapolation (CSE) for estimating the MLP. All three methods are based on tracking the Thévenin Equivalent (TE) of the system as seen from the load buses using data from Phasor Measurement...
In this paper, observability reliability (OR) and loss of data expectation indices (LODE) are calculated considering data uncertainty. Single contingency of Phasor Measurement Unit (PMU) and branch outages are considered in the calculations and to achieve more realistic results, it is assumed that failure data (repair time and failure rate) of all branches and PMU components have uncertainty. Fuzzy...
This paper presents the construction of a Hardware-in-the-loop laboratory test set-up designed to assess the time synchronization requirements of Phasor Measurement Units (PMUs). The test set-up also allows to investigate the effects of signal phase shifts caused by current and voltage transformers, errors in timing source and the impact of these errors when determining time synchronization compliance...
This article characterizes experimentally the relation between phase and magnitude error from Phasor Measurement Units (PMU) in steady state and study its effect on real-time stability assessment methods. This is achieved by a set of laboratory tests applied to four different devices, where a bivariate Gaussian mixture distribution was used to represent the error, obtained experimentally, and later...
This paper proposes a method to consider the impact of the wind farms maximum current limits on real-time voltage stability assessment. The approach is based in a multi-port equivalent of the system which makes possible to assess the effect of each wind farm limit on the stability boundary, the approach indicates the distance to the limit activation and the effect of each load in such a limit. The...
This paper introduces a robust fault location method that utilizes wide area phasor measurements and sparse estimation technique. The proposed method transforms the fault location problem into estimating sparse bus injections in the network, based upon the equivalence in the change of bus voltages between a fault current drawn at an arbitrary point along a line and virtual superimposed current injections...
This paper reports a study about the inclusion of voltage and current synchronized phasor measurements in the process of Power System State Estimation (PSSE). In order to do this, a least square state estimator that processes both SCADA and synchronized phasor measurements were developed. The effects of synchronized phasor measurements inclusion in the process of PSSE are analysed in terms of observability,...
To prevent critical power system conditions dedicated out-of-step protection schemes are used in high-voltage networks, otherwise referred to as asynchronous operation protection automation. Structure of out-of-step automation is proposed in this paper addressing angular instability between multiple areas of the grid.
In order to identify the dynamic signature of power systems, it is important to monitor the generator rotor angles. The rotor angles can be obtained either by direct measurements of the rotor position or by indirect calculation of rotor angle from voltage and current measurements. Considering limited availability of direct measurements of rotor angles the indirect method is used in this paper taking...
This paper presents a PMU-based state estimation algorithm that considers the presence of flexible AC transmission system (FACTS). The models of FACTS devices, including thyristor- and converter-based devices, are developed and then combined with an AC network model. Considering the characteristics of PMU measurements, the network model for state estimation is separated from the measurements. By applying...
This paper presents a two-step approach for defining coherent generators in disturbed power systems based on the similarity among their inter-area oscillations and swing curves. In the first step, an online visualization of the generator swing curves is performed by extracting time domain solutions of the swing equation using PMU measurements. In the second step, the similarity between each pair of...
This paper presents a robust self healing algorithm for the two-level state estimation (SE), including both the substation and control center levels. The SE is based on the presence of phasor measurement units (PMUs) at the substations. Even though the cost of PMUs has been decreasing lately, logistic, economic and design aspects limit the installation of PMUs at all nodes of electric grids. Therefore,...
The paper describes the development of a Hardware-in-the-Loop (HIL) test platform for the performance assessment of a PMU-based sub-second linear Real-Time State Estimator (RTSE) for Active Distribution Networks (ADNs). The estimator relies on the availability of data coming from Phasor Measurement Units (PMUs) and can be applied to both balanced and unbalanced ADNs. The paper first illustrates the...
Online voltage instability monitoring based on estimation of the Thevenin impedance has been thoroughly studied in many works. This equivalent impedance can be approximated either by phasor measurements of the load voltage and current or by these measurements in combination with system topology. Both approaches have their own characteristics, which are closely examined in this paper. The study is...
This paper presents the practical use of Prony Analysis to identify small signal oscillation mode parameters from simulated and actual phasor measurement unit (PMU) ringdown data. A well-known two-area four-machine power system was considered as a study case while the latest PMU ringdown data were collected from a double circuit 275 kV main interconnector on the Irish power system. The eigenvalue...
This paper assesses time synchronization sources suitable for Phasor Measurement Unit (PMU) applications in power systems. The paper investigates PMU phase error due to PMU timing inaccuracy and the presence of current and voltage transformers. This paper also shows that in practical on-field applications of commercial PMUs, the required accuracy of the time source should be better than the 31.8µs...
The simulation of Phasor Measurement Units (PMUs) into real-time simulators (RTSs) is typically limited by the complexity of the synchrophasor estimation (SE) algorithm. This is especially true when dealing with distribution network PMUs due to the more demanding accuracy requirement and, for the case of class-P PMUs, for the limited latency. In this respect, if the SE algorithm is too simplistic,...
In recent years, the Phasor Measurement Unit (PMU) technology is rapidly evolving towards the potential deployment also in power distribution systems (DSs). In general, this specific field of applications requires PMUs whose accuracy levels are beyond those required by the IEEE Std. C37.118. Additionally, there is the need to define the architecture of an associated calibration system capable to assess...
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