Reference of mutual inductance voltage of oil immersed transformer
Writer： Hengfeng you electric Time：2023-05-09 views：times
The same name terminal of oil immersed transformer specifies that the terminal where the induced current flows into the coil and the positive terminal of mutual inductance voltage in another coil are called the same name terminal of two coupling coils, and they are marked with asterisk or small black dot. If the current enters the same name end of a coil, the reference polarity of the mutual inductance voltage is positive at the same name end of the second coil, or if the current flows out from the same name end of a coil, the reference polarity of the mutual inductance voltage is negative at the same name end of the second coil.
Classification and requirements of oil immersed transformer leads: the leads of power oil immersed transformer include round copper wire, copper bar and flexible copper wire. Round copper wire shall be used when the lead diameter is less than 12mm. The cross section of the lead is 80 ~ 100 mm? Copper bars shall be used when. Soft copper wire is suitable for complex leads and is widely used in large and medium-sized power oil immersed transformers.
The connection between leads and coil wires and the connection between leads are mostly brazed. Small wires are also welded. Argon arc welding is used for the connection of aluminum coil and copper lead. The connection between the lead and the sleeve, the lead and the tap changer can be made detachable with bolts, or the soft lead and the connection end can be fixed by crimping method.
Take a group of windings on the primary side and a group of windings on the secondary side. Either end of the two groups of windings shall be shorted together. Use LCR digital bridge to test the inductance value of the other end of the two groups of windings. If the inductance value is greater than the sum of the inductance values of the two groups of windings tested separately, the two ends of the test are synonymous ends, and vice versa. Note: when it is a synonymous end, l = L1 + L2 + 2m (M is mutual inductance); when it is a homonymous end, l = L1 + l2-2m (M is mutual inductance).
