Measurement Uncertainty Evaluation of Transmission Line Parameters

Muscas

IEEE Trans. Instrum. Meas.

et al. 2022

Several monitoring, protection, and control applications designed for modern power grids are based on detailed grid models and thus require an accurate knowledge of line parameters. A synchronized monitoring infrastructure based on Phasor Measurement Units (PMUs) may be of great support to the task of line parameters estimation, but the accuracy of the estimated parameters may be largely affected by the uncertainty of all the elements of the PMU-based measurement chain. Thus, an accurate parameters estimation must appropriately consider the metrological behavior of all these elements, and in particular that of instrument transformers. To address this challenge, the paper proposes an enhanced multi-branch method for accurate estimation of the line parameters and of the systematic measurement errors introduced by the instrument transformers when measurements for multiple operating conditions are considered. Indeed, multiple operating conditions are dealt with properly, thanks to an in-depth analysis of the problem modeling within the framework of Tikhonov regularization. The validity of the proposed approach is confirmed by the results obtained on the IEEE 14 bus test system.

Section: A Estimation On a Set Of Selected Branchesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Enhanced PMU-Based Line Parameters Estimation and Compensation of Systematic Measurement Errors in Power Grids Considering Multiple Operating Conditions

Muscas

IEEE Trans. Instrum. Meas.

et al. 2022

“…In the following, the multiple-branch approach with "k m = 1" (Proposed Method) is compared with two estimation methods from literature. In particular, the first considered method (Method A) is a direct estimation method for transmission line parameters based on the equations in [25]- [26]. For the sake of a more comprehensive comparison, an extension of such direct method to include tap-changing transformer branches (using traditional model, i.e., with k m = ∞) has been designed and applied.…”

Section: Comparison Analysismentioning

confidence: 99%

Estimation of Line Parameters, Tap Changer Ratios, and Systematic Measurement Errors Based on Synchronized Measurements and a General Model of Tap-Changing Transformers

IEEE Open J. Instrum. Meas.

Solinas

et al. 2022

A primary requirement for the transmission system operator is an accurate knowledge of grid parameters. Moreover, the availability of effective and accurate monitoring tools allows the proper operation of power transmission grids. However, in spite of the now widespread possibility of having monitoring systems based on synchronized measurements, the monitoring applications can be affected not only by the inevitable uncertainty sources but also by the simplified or incomplete modelling of the network components. For this reason, the impact on power system monitoring and control applications of tap-changing transformer models is a key point. In this scenario, this paper presents a method to estimate simultaneously line parameters, tap changer ratios and systematic measurement errors associated with the instrument transformers. The method exploits a flexible model of the tap-changing transformer based on a parameter representing the ratio between the two winding impedances of the transformer. The proposal is based also on the suitable modelling of the measurement chain and on the constraints introduced by the equations of involved transmissions lines and transformers. The validation has been carried out by means of tests performed on the IEEE 14 Bus Test Case.INDEX TERMS phasor measurement units (PMUs), power transmission lines, tap changers, instrument transformers, parameter estimation, voltage measurement, current measurement, measurement errors.

“…Accurate knowledge of power network parameters and actual operating conditions is essential for several monitoring and control applications. The transmission line parameters are critical for any application, but they are usually obtained from offline calculations based on assumptions concerning, for example, the conductors geometry and length, therefore actual values may be significantly different from those stored in the Transmission System Operator (TSO) database [1], [2]. The tap changer is critical, for example, in voltage stability applications [3], because the tap changer impacts on the margins of voltage stability and has important effects on voltage monitoring and control operations.…”

Section: Introductionmentioning

confidence: 99%

PMU-Based Estimation of Systematic Measurement Errors, Line Parameters, and Tap Changer Ratios in Three-Phase Power Systems

IEEE Trans. Instrum. Meas.

Solinas

et al. 2022

The availability of accurate data is fundamental for several monitoring and control applications of modern power grids. Nevertheless, the knowledge of critical data such as transmission line and transformer parameters is often affected by uncertainty. This can lead to important problems in the correct management of the power systems. In spite of a monitoring infrastructure that is being renewed thanks to new generation devices providing synchronized measurements, the actual values of line parameters and tap changer ratios are still affected by uncertainty sources that need to be properly considered. The behaviour of all the elements involved in the measurement chain must be duly modelled. This paper proposes an improved method to carry out the simultaneous estimation of line parameters, tap changer ratios, and systematic measurement errors for a three-phase power system. The proposed method is based on the suitable modelling of the measurement chain and on three-phase constraint equations (voltage drop and current balance) of all the components involved. Its effectiveness is confirmed by tests performed on a IEEE 14 bus test system reproduced as a threephase system under different operative conditions.