50MVA Power transformer and Oil-immersed Rectifier Transformer for induction furnace 1,Low loss, 2,low partial discharge 3,Enviromental Protection 4,Loss impedance
1.The rectifier transformer's load is non-linear impedance, and valve side windings of rectifier transformer would get the currents which contain fundamental and other high-order harmonic superposition. And line side also gets corresponding non-sinusoidal currents connected by rectifier circuit coupling method.
The valve side of rectifier transformer has a variety of special coupling method, such as: dual-back-star with inter phase reactor, three-phase bridge, star-delta parallel, six-phase bridge by inter phase reactor.
3,These high-power rectifier transformer is needed to use star-delta winding phase displacement, phase-shift windings by phase displacement, autotransformer phase displacement, to improve the number of pulse of rectifier equipment.
4,According to the user’s process requirements, the rectifier transformer line side voltage is required (such as 220kV) straight down to a very low valve side voltage (such as 1kV). The valve side voltage of rectifier transformer is required within a wide range of on-load tap from 5% - 105%.
5.Self-saturable reactor can be used to change over and stabilize voltage in order to smooth rectify voltage. And some use silicon control to regulate voltage.
6.Valve side current of high-power rectifier equipment is very large, reaching 100kA and even greater,it’s required the technology of reverse-phase parallel.
7.With the wide application of AC frequency control technology, newly developed three-crack drive rectifier transformer came into being. And the lower voltage valve side of this transformer cracked into three independent branches, which can be made to supply for three different load power, which achieve “ multi functional ” effect, reducing loss and saving area.8,Power and magnetic shielding technology and so on are used.