Compared with ordinary power transformers, the traction transformer used in electrified railways has a worse operating environment and is subject to frequent overload and short-circuit shocks (generally, instantaneous short-circuit 70 times/a) 1. Traction transformer internal fault analysis electrified railway use Compared with ordinary power transformers, traction transformers have a more harsh operating environment and are subject to frequent overload and short-circuit shocks (generally, instantaneous short-circuits of 70 times/a), and such shocks will cause large internal traction transformers. The electromagnetic induction force makes the mechanical balance system of the traction transformer unbalanced, thereby destroying the magnetic circuit, circuit and insulation material of the traction transformer, and then the electrical damage is caused by the accumulation effect, which ultimately affects the normal operation of the traction transformer. CROWN Support by our mechanical engineering facilities such as reliable test laboratory, an anechoic chamber, wind tunnel, auto balancer and other high technology appliances. We believe that high performance, reliable quality and competitive price of our products will satisfied your needs.We can provide DC Axial Fan 70x70x25,Server DC Axial Fan 70x70x25,High Quality DC Axial Fan 70x70x25. DC Axial Fan 70x70x25,Server DC Axial Fan 70x70x25,High Quality DC Axial Fan 70x70x25 Crown Electronics CO., LTD , https://www.crownelectronicstw.com
Traction transformer faults can be divided into transient faults and latent faults. TTM-I is mainly used to monitor the latent faults of traction transformers. Latent faults can be attributed to three major categories: thermal faults, electrical faults, and insulation moisture. When a fault such as overheating or discharging occurs, the insulating oil is cracked, a faulty gas is generated, and partially dissolved in the oil. According to statistics, the probability of thermal faults in traction transformers is much higher than electrical faults.
According to the mechanism of fault gas generation and the statistical analysis of the gas data of fault characteristics of many traction transformers, the author finds that the fault characteristic gas of traction transformer has the following characteristics:
(1) Acetylene and hydrogen are the main characteristic gases of discharge faults, and these gases are secondary components in overheat faults.
(2) Methane and ethylene are the main characteristic gases of superheat faults, and these gases are secondary components in discharge faults. And as the temperature increases, the proportion of hydrogen and methane in the total amount of hydrogen hydrocarbons becomes smaller and smaller, and the proportion of ethylene becomes larger and larger. In the case of medium and high temperature overheating faults, the proportion of hydrogen is generally less than 15%.
(3) Ethane accounts for a small proportion of both discharge and overheat faults, and the difference between the two is small.
(4) The insulation moisture is manifested as a large hydrogen content and dominates.
(5) The traction transformer has been subjected to load or short-circuit shock for a long time, which accelerates the decomposition of solid insulation. The performance of the traction transformer is generally higher than that of the ordinary power transformer.
According to the characteristics of the traction transformer fault characteristic gas, TTM-I adopts the corresponding algorithm, which effectively avoids the fault false alarm caused by the impact load.
2. Traction transformer online monitoring The DGA online monitoring method that can be used for on-line monitoring of traction transformers can be summarized into four methods.
(1) Measure the total number of points of flammable gas. Such devices are complex in structure and expensive, and are not suitable for on-line monitoring of traction transformers.
(2) Measure the volume fraction of a single gas. Such devices are simple in structure and low in cost, but are easy to alarm for high temperature thermal faults.
(3) Measure the combined volume fraction of several gases. This type of device works well, has a simple structure and low cost. This solution can be improved to monitor the operating state of the traction transformer. The SYPRO-TEC HYDRAN201R unit in Canada mainly tests the combined volume fractions of hydrogen, carbon monoxide, ethylene and acetylene, which have been put into use in power systems for many years, and the effectiveness has been proven.
(4) Measure the volume fraction of various gas components. The structure of such devices is quite complicated, the stability is not good, the equipment cost is high, and it is not suitable for popularization in the electrified railway system.
When the traction transformer has a discharge fault and a low temperature fault, the hydrogen content is relatively large, so the change of the hydrogen volume fraction can well reflect the state of the traction transformer. However, when the traction transformer has a high temperature or low temperature thermal fault, the volume fraction of hydrogen accounts for a small proportion of the total number of hydrogen hydrocarbons, especially in the case of high temperature thermal faults, the volume fraction of hydrogen is less than 15% of the total number of hydrogen hydrocarbons. The higher the temperature, the lower the proportion of hydrogen content. Long-term experience shows that when the traction transformer has a high temperature thermal fault, the transformer oil will produce a large amount of ethylene. As the temperature increases, the ethylene content will increase rapidly. When the oil temperature exceeds 800, a small amount will be generated in the traction transformer oil. Acetylene. It can be seen that ethylene is the main component of the high temperature fault of the traction transformer. Therefore, the system takes the volume fraction of ethylene as one of the main components of the integrated volume fraction. The online monitoring system in foreign countries also monitors the comprehensive volume fraction of various gases, but it does not consider much ethylene. It is easy to leak alarms for high temperature faults and is not suitable for use in high-speed railway traction power supply systems. Http://news.chinawj.com.cn Submission: