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Buried transformer

The 6kV, 10kV, and 35kV power grids in the power system generally adopt a neutral point ungrounded operation mode.

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Underground Box Transformer

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The 6kV, 10kV, and 35kV power grids in the power system generally adopt a neutral point ungrounded operation mode. The low-voltage side of the main transformer in the power grid is generally connected in a delta configuration, and there is no neutral point that can be grounded. With the continuous expansion of urban power grids and the increasing number of cable outlets, the system's capacitance current to ground increases sharply, and the capacitance current flowing through the fault point after single-phase grounding is relatively large (exceeding 10A). In order to reduce the ground capacitance current during single-phase grounding faults, compensation devices such as arc suppression coils need to be installed at the neutral point of the transformer. Therefore, a neutral point needs to be artificially established to connect the arc suppression coil at the neutral point, reduce the ground short-circuit breaking current, and improve the reliability of the system power supply. In addition, single-phase grounding is a common fault during the operation of the generator, and the occurrence of arc grounding at the fault point will further expand the insulation damage of the stator winding. The high resistance grounding of the neutral point of the generator can effectively suppress the grounding fault current of the generator, thereby preventing the stator winding of the generator from burning out and reducing the transient overvoltage of arc grounding. For this purpose, our company has developed a motor neutral point grounding resistor cabinet for single-phase grounding faults in motors. It mainly consists of a single-phase grounding transformer and a resistor, which can effectively avoid damage to the generator stator winding and insulation caused by grounding current.

Buried transformer