Three-phase transformer consists of three core columns, each core column around the same phase of the two coils, one high-voltage coil, the other is low-voltage coil. Lei Lang Shanghai transformer manufacturers now to break down the three-phase transformer works:
1, the domestic 500,330,220 and 110kV transmission system voltage phasors are in phase, so the following voltage ratio of three-phase three-phase or three-phase SMPS transformers , high voltage and medium voltage windings with stars Shaped connection. When the core structure of three-phase three-core, the low-voltage windings can also be used star connection or angle connection, it is determined by the low-voltage transmission system with the voltage phasor and high voltage transmission system voltage phasor phase or lag 30 ° electrical angle.
500/220 / LVkV - YN, yn0, yn0 or YN, yn0, d11
220/110 / LVkV - YN, yn0, yn0 or YN, yn0, d11
330/220 / LVkV - YN, yn0, yn0 or YN, yn0, d11
330/110 / LVkV - YN, yn0, yn0 or YN, yn0, d11
2, 60 and 35kV of the domestic transmission system voltage has two different phase angle.
Such as 220 / 60kV transformer using YNd11 connection, and 220/69 / 10kV transformer with YN, yn0, d11 connection, the two 60kV transmission system a difference of 30 ° electrical angle. When 220/110 / 35kV toroidal transformers adopts YN, yn0, d11 connection, 110/35 / 10kV transformer adopts YN, yn0, d11 connection, the above two 35kV transmission system voltage phasor is also worse 30 ° electrical angle. Therefore, the decision 60 and 35kV winding connection method to be careful, connection must meet the requirements of the transmission system voltage phasor. According to the relative relationship between the voltage phasor 60 and 35kV-level winding connection. Otherwise, even if the capacity of the voltage ratio is also on the transformer can not be used, not connected, the transformer can not be connected with the transmission system.
3, the domestic 10,6,3 and 0.4kV transmission and distribution system phasor has two phases. In Shanghai, there is a 10kV and 110kV transmission system voltage phasor difference of 60 ° electrical angle, then can be 110/35 / 10kV voltage ratio and YN, yn0, y10 connection of three-phase three-winding power transformer, but limited Three-phase three-core core-core.
4, but pay attention to: single-phase transformer in the three-phase connection into the group, you can not use YNy0 connected three-phase group. Three-phase shell-type transformer can not be connected with YNy0.
Three-phase five-column core transformer must be used YN, yn0, yn0 connection, the transformer must be connected into the angle of the fourth winding connection, it does not lead out of the head (structure to do the electrical test leads to the head is not This example).
5, the connection of different groups of parallel operation of the transformer, the general provisions of the link group label must be the same.
6, the distribution transformer for multi-mine areas, you can use Yzn11 connection, when using z-connection, the impedance voltage and Yyn0 connection algorithm is different, while the connection of the copper consumption of z winding to be more. Yzn11 connected distribution transformer lightning protection performance is better.
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