LAV Based Robust State Estimation for Systems Measured by PMUs

Göl, Murat; Abur, Ali

doi:10.1109/tsg.2014.2302213

Cited by 206 publications

(109 citation statements)

References 20 publications

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“…Since estimating all system parameters has a high computational burden, local parameter estimation is preferred. Consider the two-bus system given in the Figure, where g 12 is the series conductance, b 12 is the series susceptance, and b 11 is the charging-susceptance, which is assumed to be equal to b 22 , of the transmission line between buses 1 and 2. The relation between the system parameters and the voltage and current phasor measurements taken by a PMU can be expressed as below, where V k is the voltage phasor of bus k and I meas ij is the measured current phasor between buses 1 and 2.…”

Section: Proposed Methodsmentioning

confidence: 99%

Robust local parameter estimator based on least absolute value estimator

Özdemir¹,

Göl²

2017

Turk J Elec Eng & Comp Sci

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Abstract:Changes in weather conditions such as temperature and humidity, miscommunication between the control center and circuit breaker transducers and tap changers, and inaccurate manufacturing data may cause parameter errors. Because of incorrect parameters, the state estimator may provide biased state estimates, which may lead to many serious economic and operational results. In order to prevent that, one must identify and correct those parameter errors. This work proposes a local parameter estimator based on the least absolute value (LAV) estimator, which is known to be robust against bad measurements, i.e. measurements with gross error. Considering the increasing number of phasor measurement units (PMUs), as well as their fast refresh rate and high accuracy, the proposed method will employ PMU measurements in local parameter estimation. In general, a PMU measures the current phasor flowing through a branch and the voltage phasor of the sending bus of that branch. However, those two measurements are not sufficient to estimate the parameters of the considered branch. Therefore, multiple measurements taken at different time instants will be used in the parameter estimation process for measurement redundancy, assuming that the line parameters and transformer taps are constant. The proposed method also assumes that the state estimates are available.The LAV estimator is computationally expensive, but it provides unbiased state estimates even in the presence of bad data, provided that enough measurement redundancy is available. This deficiency will be eliminated by performing local parameter estimation.

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Section: Proposed Methodsmentioning

confidence: 99%

Robust local parameter estimator based on least absolute value estimator

Özdemir¹,

Göl²

2017

Turk J Elec Eng & Comp Sci

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“…In large meshed distribution systems these leverages can occur due to the presence of line power flow measurements on short lines [4] and also due to the lower redundancy of measurements.…”

Section: Attack Strategiesmentioning

confidence: 99%

“…However, the leverage measurements are not protected. The leverages can occur both in transmission and distribution networks [4]. This requires to develop a methodology to deal with the situation.…”

mentioning

confidence: 99%

Bad data detection in the context of leverage point attacks in modern power networks

Majumdar

2017

2017 IEEE Power &Amp; Energy Society General Meeting

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Abstract-This paper demonstrates a concept to detect bad data in state estimation when the leverage measurements are tampered with gross error. The concept is based on separating leverage measurements from non-leverage measurements by a technique called diagnostic robust generalized potential (DRGP), which also takes care of the masking or swamping effect, if any. The methodology then detects the erroneous measurements from the generalized studentized residuals (GSR). The effectiveness of the method is validated with a small illustrative example, standard IEEE 14-bus and 123-bus unbalanced network models and compared with the existing methods. The method is demonstrated to be potentially very useful to detect attacks in smart power grid targeting leverage points in the system. Index Terms-distribution management system (DMS), remote terminal unit (RTU), state estimation (SE), leverage measurements, bad data detection (BDD), generalized studentized residuals (GSR), diagnostic-robust generalized potentials (DRGP)

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“…One common centralized approach named the weighted least squares (WLS) has been widely used for PSSE, employing a nonlinear measurement model. In recent years, phasor measurement units (PMUs) have drawn much attention because they can provide voltage and current phasors and the measurement model becomes linear [2,3]. The computation complexity will become simpler.…”

Section: Introductionmentioning

confidence: 99%

“…Even though PMUs can result in measurements with higher accuracy, the PSSE still constitutes a major challenge due to the presence of bad data or outliers [3,4,5]. Such outliers that are far away from the expected measuring data create the potential risk of misleading the estimated result [6].…”

Section: Introductionmentioning

confidence: 99%

Distributed State Estimation Using a Modified Partitioned Moving Horizon Strategy for Power Systems

Chen

Foo

Ling

et al. 2017

Sensors

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In this paper, a distributed state estimation method based on moving horizon estimation (MHE) is proposed for the large-scale power system state estimation. The proposed method partitions the power systems into several local areas with non-overlapping states. Unlike the centralized approach where all measurements are sent to a processing center, the proposed method distributes the state estimation task to the local processing centers where local measurements are collected. Inspired by the partitioned moving horizon estimation (PMHE) algorithm, each local area solves a smaller optimization problem to estimate its own local states by using local measurements and estimated results from its neighboring areas. In contrast with PMHE, the error from the process model is ignored in our method. The proposed modified PMHE (mPMHE) approach can also take constraints on states into account during the optimization process such that the influence of the outliers can be further mitigated. Simulation results on the IEEE 14-bus and 118-bus systems verify that our method achieves comparable state estimation accuracy but with a significant reduction in the overall computation load.

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LAV Based Robust State Estimation for Systems Measured by PMUs

Cited by 206 publications

References 20 publications

Robust local parameter estimator based on least absolute value estimator

Robust local parameter estimator based on least absolute value estimator

Bad data detection in the context of leverage point attacks in modern power networks

Distributed State Estimation Using a Modified Partitioned Moving Horizon Strategy for Power Systems

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