Browsing by Author "Hettiarachchige-Don, A. C. S"

Now showing 1 - 7 of 7

Embargo
Assessment of System Reliability in Presence of Cyber Attack Risk on PMU Data
(IEEE, 2018-12-21) Hettiarachchige-Don, A. C. S; Manoharan, A. K; Pedaprolu, L. G; Pedaprolu, V
This paper provides an assessment of the effect of Synchrophasor Measurement Units in improving power system reliability. First, an overview of cyber threats to PMU networks is given where the possible vulnerabilities of the network to malicious data manipulation are studied. The addition of PMUs to the power system infrastructure would offer greater observability in the system and thus mitigate the risk of transmission line failure due to thermal overloading. However, the addition of PMUs opens the system to cyber threats that might, in fact, lower system reliability. The analysis in this work looks at the effect of these threats on the overall system reliability of a real system layout based on real PMU data obtained from a utility. The benefit to a utility in including PMUs under the varying levels of cyber threat is also studied.
Embargo
Dynamic line parameter estimation using synchrophasor measurements
(IEEE, 2016-12-16) Hettiarachchige-Don, A. C. S; Aravinthan, V; Jewell, W; Westervelt, S
This paper proposes a novel methodology for the calculation and estimation of transmission line impedance with the use of real time data from synchrophasor measurement units. Current synchrophasor standards do not provide impedance data and must therefore be calculated. The algorithms used in this paper include impedance calculation, outlier detection and elimination as well as denoising using regularized least square estimation. The proposed methodology operates using a small sample size and can therefore be applied in real time to provide operators with instantaneous impedance values from transmission lines. The paper also investigates how changing several methodology parameters can affect the accuracy of the output obtained. The overall methodology as well as these parameters have been tested using real synchrophasor data from an American utility provider.
Open Access
Dynamic line parameter estimation using Synchrophasor Measurements
(Wichita State University, 2021-05) Hettiarachchige-Don, A. C. S
The worldwide push towards a more intelligent, connected and reliable electric power delivery system has led to the propagation of a wide range of new technologies and ideas within the power grid infrastructure. Thus, the power grid is becoming more adaptable to changes and more reliable under distress. However, these benefits are only possible with vastly improved observability in the system. The traditional methods and technologies for grid monitoring were simply too slow and newer, faster and more accurate monitoring technologies became essential over the turn of the century. With the advancement of micro processing and communication technologies at an incredibly fast pace, this became possible in the form of smart monitoring devices. These devices include Intelligent Electronic Devices (IEDs), smart meters for homes and, at the transmission level, the use of Synchrophasor Measurement Units (PMUs). Over the past decade, transmission utilities were quick to adopt these PMU networks and they are now common among most major utilities. Compared to traditional monitoring systems, PMUs provide information at a much higher resolution and have the advantage of being time synchronized. The benefits of these networks are numerous, but they are not without certain drawbacks. PMU devices only report some basic system parameters from the field. While these are useful on their own, it is possible to use this data, in combination with other information, to extrapolate additional parameters about the grid. However, in this process, inherent errors present in PMU estimated data become an issue and renders the results of this extrapolated information unusable. In this work, of particular focus from these additional parameters is transmission line resistance. The fundamental cause of error will be investigated, and this knowledge will be applied to create a correction algorithm to output corrected transmission line resistance estimates that are more useful to utilities for a range of auxiliary applications such as dynamic line rating, determination of line sag, and conductor temperature estimation. This advancement would allow utilities to compound the economic benefits of their investment in PMU networks.
Embargo
Estimation of missing transmission line reactance data using multiple linear regression
(IEEE, 2017-09-17) Hettiarachchige-Don, A. C. S; Aravinthan, V
This paper explores the use of Multiple Linear Regression techniques in order to estimate sections of missing line reactance data sometimes found in the data received from synchrophasor measurement units. The high correlation between transmission line reactance and the system frequency is used to predict these estimates. Dynamic predictor coefficients are used to improve accuracy of the estimations and analysis is done to determine the most appropriate parameters to use in the regression model. All model building, analysis and testing is done using multiple sections of real PMU data.
Open Access
Realtime line parameter estimation using synchrophasor measurements and impact of sampling rates
(Wichita State University, 2016) Hettiarachchige-Don, A. C. S
The installation of synchrophasor measurement units within the electrical grid system have provided utilities with the ability to monitor their transmission system in real time. These real time observations allow for better situational awareness and rapid responses to adverse system conditions. However, the real time impedance of the powerline is not one of the parameters that is transmitted to the control center and therefore, has to be calculated using the data received from multiple devices. This thesis proposes a simplified methodology for this analysis that requires lower computation power in comparison to most other proposed estimation techniques. Hence, this methodology is able to produce accurate results faster and by using a smaller quantity of stored data. Due to these reasons, this methodology can be implemented to provide near real time estimation and reporting of impedance values. For the purposes of this research, only the reactance information will be calculated but a similar approach can be used to obtain resistance information as well. The methodology consists of an algorithm to calculate and estimate the reactance of a line using the reported PMU data. It includes an outlier detection and elimination algorithm as well as a denoising technique that makes use of regularized least square estimation to accurately estimate the reactance over the analysis period. The methodology proposed is tested using real synchrophasor measurement data from a utility provider. The proposed mythology can easily be adapted and applied for the estimation and calculation of other parameters using PMU data.
Unknown
Reliability modeling considerations for emerging cyber-physical power systems
(IEEE, 2018-06-24) Aravinthan, V; Balachandran, T; Ben-Idris, M; Fei, W; Heidari-Kapourchali, M; Hettiarachchige-Don, A. C. S; Jiang, J. N; Lei, H; Lei, C. C; Mitra, J; Ni, M; Papic, M; Parvania, M; Sephary, M; Singh, C; Srivastava, A; Stefanov, A; Sun, H; Tindemans, S
Power system operation considering an increasingly complex cyber infrastructure may be one of the key factors of the next generation power systems. The effective operation of a power system in a massively deployed cyber network environment will be affected by cyber network reliability. Therefore, it is vital not only to understand the operation of a cyber network and its reliability, but also it is critical to integrate the interdependency of cyber and power systems into power system planning and operations. This requires a three-layer approach to reliability modeling and evaluation. The cyber and power layers are interconnected by the information layer. The objective of this paper is to define the three-layer model and report a generalized framework for combined reliability modeling.
Unknown
Uncertainty Mitigation in Feeder Level Power Loss Reduction with Distributed Generation
(IEEE, 2019-04-03) Manoharan, A. K; Hettiarachchige-Don, A. C. S; Aravinthan, V
The grid is moving towards a system of decentralized distributed generation using a large number of small scale renewable generation resources. These resources are stochastic in nature and therefore have to be continuously monitored and controlled for better system operation. This calls for an Information and Communication Technology (ICT) infrastructure that is able to provide continuous generation and load data. However, losses in communication is always possible. The work in this paper tries to come up with a DG control scheme that makes it possible for the system to make meaningful decisions even during communication losses. Proposed here is a feeder level loss minimization control scheme that uses a possibilistic approach to come up with DG set points in the absence of continuous system data.