| Automatic Transform System of the station power supply is a device which can recover the bus power supply in shortest time when transformer lost electricity. When the high voltage side of spare transformer is switch on, we call it hot spare, and when the high voltage side of spare transformer is switch off, we call it cold spare. In the past, there was a kind of understanding that standby transformer was related to the safe operation of the power plant, we must use hot spare in order to run in a high reliability. If we use cold spare, whereas reduced loss, increased operating risks. However, with the development of technology, the reliability of automation equipment raised gradually, make it possible change hot spare to cold spare in standby transformer.This paper analysis the fast cutting device and transformer protection device (differential protection contains Inrush exciting current of transformer closure function) realize switching to cold spare. Using reasonable and reliable switch time sequence to realize switch, in the original support for hot spare to realize cold spare, and make the new switch device have two kinds of mode, we can choose one of them when using. Using reliable automation equipment and feasible technology can guarantee safe operation in the mode of cold spare, it can also save energy and reduce emission. If the fast cutting device and transformer protection device can’t match each other, the voltage switch may lose, and in this case bus voltage losing will bring serious consequence. Therefore, there must be reliable test results before applying cold spare. Through the dynamic model test study (including physical dynamic model and RTDS dynamic model), we simulate standby transformer switch test in various working conditions (including accident state), and confirmed the feasibility of using cold spare in the standby transformer. The test results have reference value for the research in this field. |
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