Model for 400 kV Transmission Line Power Loss Assessment Using the PMU Measurements

Ivan Pavičić,Igor Ivanković,Dalibor Brnobić,Ninoslav Holjevac

doi:10.3390/en14175562

Abstract

This paper presents an advanced model for monitoring losses on a 400 kV over-head transmission line (OHL) that can be used for measured data verification and loss assessment. Technical losses are unavoidable physical effects of energy transmission and can be reduced to acceptable levels, with a major share of technical losses on transmission lines being Joule losses. However, at 400 kV voltage levels, the influence of the electrical corona discharge effect and current leakage can have significant impact on power loss. This is especially visible in poor weather conditions, such as the appearance of fog, rain and snow. Therefore, loss monitoring is incorporated into exiting business process to provide transmission system operators (TSO) with the measure of losses and the accurate characterization of measured data. This paper presents an advanced model for loss characterization and assessment that uses phasor measurement unit (PMU) measurements and combines them with end-customer measurements. PMU measurements from the algorithm of differential protection are used to detect differential currents and angles, and this paper proposes further usage of these data for determining the corona losses. The collected data are further processed and used to calculate the amount of corona losses and provide accurate loss assessment and estimation. In each step of the model, cross verification of the measured and calculated data is performed in order to finally provide more accurate loss assessment which is incorporated into the current data acquisition and monitoring systems.

Highlights

Introduction and MotivationElectricity losses in transmission networks can be divided into technical and nontechnical losses [1]
Measurement of losses on the 400 kV over-head transmission line (OHL) based on weather forecasts, measured losses using phasor measurement unit (PMU)
This section describes each segment of the methodology and of losses on the 400 kV OHL based on weather forecasts, measured losses using PMU data determines the influence of each on the total realized loss amounts

Summary

Introduction

Electricity losses in transmission networks can be divided into technical and nontechnical losses [1]. Technical losses are caused by physical electrical effects, which can be divided into those originating from transmission line losses and transformer losses [2,3]. Non-technical losses are caused by unregistered and illegal connections, inaccurate measurements, and poor records of measurements, and it is impossible to determine the origin or the exact measure and location of these losses [4]. For high-voltage transmission networks, non-technical losses are negligible. The dominant loss share in transmission networks is generated by overhead lines (OHLs). Electricity losses on transmission lines are caused by the known physical effects of the electricity current flow and can be divided into Joule losses, losses due to the corona effect and losses on insulators, with other types of losses being neglected due their insignificant amounts [5]

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Conclusion