Research On Economic Operation Of Transformers In Transmission And Distribution Grids

The demand for energy is greatly increasing with the development of economy, following by the aggravation of contradiction between the limited energy resources and energy demand, which attracts more and more concern. China possess rich energy resources, however, energy efficiency is far behind the United States, Japan and other developed countries, and even less than Brazil, India and other developing countries. As an easy-to-use high-quality secondary energy, power is widely used in various areas of people's livelihood. Electric power industry is not only an important energy production sector, but also energy-hungry. The total electricity consumption of electrical energy generating capacity accounts for about 28-33% according to the literature from power generation to use, therefore, it has tremendous potential to tap the energy-saving.Transformer is one of the main equipments in power system, and can consume 30% of power system loss, representing about 10% of generated energy. Therefore, it is important to investigate the method to reduce the loss of the transformer in order to save energy. The main ways to reduce power loss of transformation include updating with high energy consumption and transformation and developing energy-saving transformer, and the economic operation of transformer can also be implemented to improve operating efficiency transformers. Full use of the existing equipment and do not have to increase investment or just a slight increase in investment are the important advantages in economic operation of transformer. Therefore, it is of great significance for reducing costs and increasing effectiveness for caring out economic operation of transformer. The main works of thesis are present as follows:(1) Introducing the basic theory of the transformer, the method for calculating power loss and the characteristics of load-power loss of transformer, focusing on determining the mode of economic operation in two two-winding transformer and the algorithm of economic operation of transformer for reducing the Integrated power loss has also been given. (2) Optimizing the operation mode of transformer based on the data of Diaobingshan, and being applied in Tieling Power Supply Bureau.(3) The Method to determine the mode of a single transformer economic operation hours has been proposed according to Flow calculation, based on which, method of multi-time economic operation mode of the transformer to has been determined and the solution process has also been given. The comparison of the results in two different method by different load conditions prove that both methods have their own advantages and should be chosen for different conditions, which is consistent with the calculated results.(4) Three-dimensional zone diagram has been proposed which is based on voltage, power factor and load through improving the existing zone diagram. This method has been applied to determine the way of transformer economic operation. Simulation analysis was carried out through employing the data of Diaobingshan.