A New Approach on the Application of Substation Transformers as Measuring Transformers for Grid State Identification in Terms of Energy Management Systems

M. Mohrmann and M. Wolter (Germany)


Measuring transformers, Distribution grid, substation transformer, load and temperature dependent transformer model


Due to decentralized power generation, distribution grids are increasingly used for transmitting locally generated power. This kind of power generation is mainly based on highly fluctuating renewable sources. For safe and efficient grid management exact knowledge of the grid state is essential. Traditionally distribution grids are only sparsely equipped with the necessary measuring technique sdo extension of existing measurement facilities is necessary. The state of grids inadequately equipped with measurement technology has to be estimated.
To realize a cost-effective extension of measurement technology, the existing low voltage / mean voltage transformers could be used as measuring transformers. The extension of measuring technique in the substations could be limited to the low voltage side of transformers. Electrical parameters of low voltage sides could be used to calculate the values of the upper voltage side.

For a precise calculation, the knowledge of the operating performance of used equipment is required. In this paper a method for determining the load and temperature dependent behavior of three-phase transformers is introduced. The creation of load dependent mathematic models is described.

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