Why Must The Diesel Generator Set Be Grounded

Many users know that in order to ensure the personal safety of diesel generator set operators and meet the needs of power system work, diesel generator sets have strict grounding requirements. The grounding methods of diesel generator sets include working grounding, protective grounding and catching Connect the zero three, this article Jiangsu Starlight Electricity Equipments Co.,Ltd. will explain in detail why the diesel generator set must be grounded.

I. Working grounding

Working grounding is to ground the neutral point, and its purpose is:

1. Reduce the electric shock voltage. For a system where the neutral point is not grounded, when one phase is grounded and the human body touches one of the other two phases, the electric shock voltage is more than 1.7 times the phase voltage; for the neutral point grounded system, the electric shock voltage drops to close to or equal to the phase voltage.

2. Cut off the faulty equipment quickly. For a system where the neutral point is not grounded, when one phase is grounded, due to the capacitance and insulation resistance between the wire and the ground, it can form a current path. The ground current is very small, which is not enough to cause the protection device to act and cut off the power supply, which cannot ensure personal safety. . For a system with a neutral point grounded, when one phase is grounded, the ground current is large, the protection device will act quickly to disconnect the fault point.

3. Reduce the insulation level of electrical equipment to the ground. In a system where the neutral point is not grounded, when one phase is grounded, the ground voltage of the other two phases will rise to the line voltage. As for the neutral-grounded system, when one phase is grounded, the ground voltage of the other two phases is only close to the phase voltage, so the insulation level of electrical equipment and transmission lines can be reduced.

II. Protective grounding

Protective grounding is often used in low-voltage systems where the neutral point is not grounded. Its function is: when the insulation structure of a certain winding of the motor is damaged and the shell is charged, if it is not grounded, the human body touches the shell, which is equivalent to a single-phase electric shock. There is a risk of electric shock. If protective grounding is used, when the human body touches the shell, the human body resistance is connected in parallel with the grounding resistance, and the human body resistance is much larger than the grounding resistance, so the current through the human body is very small, and there is no danger of electric shock.

III. The protection is connected to zero

The protective zero connection is often used in low-voltage systems where the neutral point is grounded. Its function is: When the insulation structure of a certain winding of the motor is damaged and it is connected to the shell, because the protection is connected to zero, a single-phase short circuit is formed, and the fuse in this phase is quickly blown, and the shell is no longer live. Even when the human body touches the shell before the fuse is blown, since the human body resistance is much greater than the line resistance, the current passing through the human body is also very small, and there is no danger of electric shock.

Through the above introduction, I believe everyone understands why the diesel generator set must be equipped with a grounding wire when assembling. Jiangsu Starlight Electricity Equipments Co.,Ltd. would like to remind users that in addition to connecting the grounding wire correctly, the diesel generator set should be used correctly in accordance with the rules of use. Otherwise, operation accidents may occur and personal safety will be affected.

For more details, please contact us with sales@dieselgeneratortech.com