Study On Economic Operation Of Transformer In Distribution Network And Auto-switching Device

The transformer is one of the essential equipment in the power system. Its total capacity far exceeds that of the generator and its power loss accounts for a large part of the power system loss, so the operation way of transformers has a large impact on the power loss. Transformers in distribution network have some characteristics, such as large quantities, low degree of automation, large losses in a non-operational operation state. It is important to implement economic operation of transformers, which will reduce the operation and maintenance cost, production cost of the plant and energy loss.Because of the low degree of automation and energy conservation space, two-winding transformers in the distribution network are taken as the main object to study on how to reduce losses and how to determine the switching point of operation ways. Case analysis shows the energy conservation space of economic operation. Due to the large quantities and wide distribution of transformers in distribution network, transformer auto-switching devices are necessary to save manpower by automatically switching the operation state of transformers which will improve the degree of automation and promote the implementation of economic operation. The main research contents are as follows:1. Initial operation areas are divided by intersections of different transformer loss curves. Based on fuzzy decision method, length and power-saving rate are considered as important factors to calculate priority values of different operation areas. Then keep removing the operation area with minimum priority until the switching times is fulfilled to obtain optimum economic operation switching points.2. Load variation trend is analyzed according to the load curve. The switching points which are decided by fuzzy decision are converted to switching areas with time interval control method. It makes economic operation less dependent on the load curve and more flexible.3. The residential and factory actual load conditions are taken as samples to divide economic operation areas and switching areas. Case analysis results reveal that the switching strategy of economic operation can reduce the transformer switching times and obtain the maximum economic benefits. The implementation of economic operation of transformers can effectively reduce transformer losses and reduce production costs.4. Auto-switching devices based on DSP2812 for transformers are developed, which can switch transformers automatically and make operation of transformers economic. The inrush elimination algorithm is integrated into devices to suppress inrush current and promote the implementation of economic operation. This Paper shows the hardware structure and algorithm. A prototype is made and prototype test results confirm the analysis and design.