Uncertainty evaluation of loss measurements

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Uncertainty evaluation of loss measurements

An important extension of the state of the art is a study of detrimental factors that occur on-site in the industrial environment where these systems are used, such as interference and non-sinusoidal input signals. This will ensure that the required challenging uncertainties can be achieved by industrial end-users. Given the complexity of loss measurements, the uncertainty evaluation of these measurements is also complex. Therefore the project is developing good practice guides to provide end-users with the necessary guidance in this uncertainty evaluation, extending the present guidance of the IEC 60076-19 standard. [link]

Guidance on uncertainty analysis of reactor loss measurements

Given the technical complexity of accurate loss measurements, the uncertainty evaluation of transformer and reactor loss measurements is also complex. The project is developing the necessary guidance for power transformer and reactor manufacturers for the measurement uncertainty evaluation of their products. To this end, extensive input was provided to the present revision of the IEC 60076-19 standard on uncertainty evaluation of power transformer loss tests. In addition, work has started to extend the IEC and CENCELEC 60076-19 standards on the uncertainty evaluation of reactor measurements. Together with the Chief Stakeholder ABB AB Power Transformers, a mathematical model function for uncertainty analysis of reactor loss measurements has been drafted.

Effects of non-sinusoidal waveforms

A final important step forward with respect to the state-of-the-art is a study on the effects of non-sinusoidal waveforms on loss measurement uncertainty. So far, all LMS calibrations are performed with sinusoidal waveforms only. This is close to the actual conditions during reactor loss measurements, but far away from the conditions during no load loss measurement of transformers, where the current Total Harmonic Distortion can easily be 60 %. A literature review has been performed on the non-sinusoidal waveforms during power transformer and reactor loss measurements. Based on this review, test conditions are identified under which waveforms will be collected by the project partners during actual transformer or reactor tests at the locations of 2 project stakeholders. The final aim of this activity is to provide more clarity on the loss measurement uncertainty under these non-ideal conditions.