Bus processing machine cleaning method, the choice of sealing ring?

Posted by bruce zhu on August 25th, 2023

Bus processing machine cleaning method, the choice of sealing ring?

The busbar bender has very high requirements on current. For the unbalanced current caused by the difference between the calculated transformation ratio and the actual transformation ratio of the current transformer, two methods can be used to overcome it:

Another situation is caused by environmental conditions, such as strong interference (grid or peripheral equipment), high temperature, high humidity, etc. This environmental factor is often ignored by people. For example, in the southern region, the machine tool is placed in an ordinary factory building or even close to the open door. The electric cabinet runs with the door open for a long time, and there are a lot of equipment that produces dust, metal shavings or water mist nearby.
One is to use an autotransformer for compensation. Usually, an autotransformer is installed on the current transformer on one side of the transformer, and the output terminal of the LH is connected to the input terminal of the converter. When changing the transformation ratio of the autotransformer , the output current of the converter can be equal to the secondary current of the LH without a converter, so that the current flowing into the differential relay is zero or close to zero.

The second is to use the balance coil of the intermediate converter for magnetic compensation. Usually, the core of the intermediate converter is wound with a main coil, that is, a differential coil, which is connected to a differential current. In addition, a balance coil and a secondary coil are wound. Connect to the side where the secondary current is smaller. Properly select the number of turns of the balance coil so that the magnetic potential energy generated by the balance coil can completely offset the magnetic potential generated by the differential coil, then no potential will be induced in the secondary coil, so the differential There is no current flowing in the dynamic relay. A differential relay with magnetic braking characteristics is used. The differential relay of the transformer is based on the speed saturated converter, and a group of braking coils are added to utilize the short-circuit current when an external fault occurs. To achieve braking, the starting current of the relay increases with the increase of the braking current. It can reliably avoid the unbalanced current when the transformer is short-circuited externally, and improve the sensitivity of the transformer when it is internally faulty.

c. The beginning of the power supply has good grounding.
Therefore, the starting current of the relay increases with the increase of the braking current. Through correct setting, the actual starting current of the relay can be greater than the corresponding unbalanced current regardless of the external short-circuit current of any size. , Transformer longitudinal differential protection can reliably avoid the unbalanced current when the transformer is short-circuited externally.

3. Do not wear scarves or overcoats to operate.