The neutral point of mining transformers is strictly prohibited from being directly grounded. This regulation is mainly based on the special safety requirements and environmental conditions underground in coal mines. The specific reasons are as follows:

　　1、 Prevent electric shock accidents

　　Direct grounding risk: If the neutral point of a mining transformer is directly grounded, in the event of a single-phase grounding fault, personnel coming into contact with live objects can easily form a closed circuit from the phase line through the human body and the ground to the neutral point, resulting in a large current passing through the human body and increasing the risk of electric shock injury.

　　Non grounding advantage: When the neutral point is not grounded, the circuit impedance is high, and the current passing through the human body is small, thereby reducing the risk of electric shock.

　　2、 Reduce the harm of short circuit faults

　　Direct grounding issue: In grounding systems, single-phase grounding faults can easily cause phase to phase short circuits, expand the scope of the fault, and increase the difficulty and danger of accident handling.

　　Non grounded advantages: A neutral point non grounded system can reduce the probability of short circuits, and when single-phase grounded, the current is small, making it easy to troubleshoot and handle faults, and reducing the scope of accidents.

　　3、 Adapt to the underground environment

　　Special environmental requirements: The underground environment of coal mines is humid, dusty, and contains flammable gases (such as gas). If the neutral point of the transformer is directly grounded, a single-phase grounding fault can generate high current sparks, which may cause serious accidents such as explosions.

　　Safety measures: In order to adapt to the underground environment, mining transformers usually use neutral point ungrounded or grounded through arc suppression coils. This method can ensure that the current in the event of a single-phase grounding fault is small, the system can continue to operate briefly for fault handling, and at the same time improve the insulation safety of the power supply system.

　　4、 Compliant with safety regulations

　　Regulations require that according to relevant safety regulations, the neutral point of underground distribution transformers in coal mines must not be directly grounded. This is to prevent serious accidents such as gas explosions caused by large currents generated by single-phase grounding faults.

　　Practical application: In practical applications, the neutral point of mining transformers is not grounded or grounded through arc suppression coils, which has been widely recognized and applied, effectively ensuring the electrical safety underground in coal mines.