Estimating the Input Voltage and Current of Transformers from Output Side Measurements

Clark, Peter (2018) Estimating the Input Voltage and Current of Transformers from Output Side Measurements. [USQ Project]


In today’s distribution environment there is a steady move towards smart grid technologies. As part of this, advanced metering infrastructure is being developed for low voltage networks including meters installed at the distribution transformer. By using this metering data to calculate the input voltage at transformers along a medium voltage feeder and then displaying it on the distribution network’s SCADA system, the performance of the medium voltage feeder can be obtained and monitored. This project is to develop, test, and analyse a model that uses low voltage metering data and transformer nameplate information to estimate the input voltage and current of a transformer. The model needs to be able to account for balanced and unbalanced network conditions. Three scenarios are tested using different methods of determining the transformers impedance angle.

The crux of this project is to model the regulation of a transformer. To do this, the method of symmetrical components has been applied to calculate the sequence voltage drops in the transformer. They are then combined with the output sequence voltages. These values are adjusted for tap position and then used to calculate the input voltage and current sequence components. Once reconstituted they reveal the input voltages and currents to the transformer. Testing on an in service transformer and abnormally loaded transformer was carried out to collect data that was used to test and validate the model. Results suggest that the model tracks the input voltage well in both balanced and unbalanced conditions. The best results were obtained using manufacturers test data for the impedance. Although considered a success, further work is required to develop the model to suit all operating environments.

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Item Type: USQ Project
Item Status: Live Archive
Faculty/School / Institute/Centre: Historic - Faculty of Health, Engineering and Sciences - School of Mechanical and Electrical Engineering (1 Jul 2013 - 31 Dec 2021)
Supervisors: Ahfock, Tony; Griffiths, Rodger
Qualification: Bachelor of Engineering (Honours) (Electrical and Electronic)
Date Deposited: 31 Aug 2022 01:26
Last Modified: 27 Jun 2023 04:53
Uncontrolled Keywords: smart grid technologies; input voltage; input current; transformers; output sequence voltages

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