Measures to ensure safe grounding of generator sets must be done in place

Next, Haixing will explain the specific content: 1. Working grounding (1) Reduce the electric shock voltage. For systems where 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 systems where neutral point grounding, the electric shock voltage drops to close to or equal to the phase voltage. (2) Quickly cut off the faulty equipment. For systems with neutral points that are not grounded, when one phase is grounded, the current path can be formed due to the presence of capacitance and insulation resistance of the wire and the ground. The grounding current is very small, which is not enough to cause the protection device to operate and cut off the power supply, and cannot ensure personal safety. For systems with neutral point grounding, when the grounding current is high after one phase is grounded, the protection device will operate 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 other two phases will be increased to the line voltage. For systems with neutral point grounding, when one phase is grounded, the voltage to ground of the other two phases is only close to the phase voltage, so the insulation level between the electrical equipment and the transmission line can be reduced. 2. Protective grounding Protective grounding is often used in low-voltage systems where neutral points are not grounded. Its function is: when the insulation structure of a certain winding of the motor has been damaged and the shell is energized, if it is not grounded and the human body touches the shell, it is equivalent to a single-phase electric shock, and the risk of electric shock may occur. If protective grounding is used, when the human body touches the shell, the resistance of the human body is connected in parallel with the grounding resistance, and the resistance of the human body is much larger than the grounding resistance, the current through the human body will be very small, and there will be no risk of electric shock. 3. Protective connection Protective connection is often used in low-voltage systems with neutral point grounding. Its function is: when the insulation structure of a certain winding of the motor has been destroyed and connected to the shell, due to the use of protective connection, a single-phase short circuit is formed, which quickly blows the fuse in this phase, and the shell will no longer be charged. Even when the human body touches the shell before the fuse is blown, the resistance of the human body is much larger than the line resistance, and the current through the human body is very small, so there will be no risk of electric shock. In addition, it is also necessary to note that the specific situation should be considered when grounding the generator neutral wire. First, confirm whether the transformer has leakage protection. Generally, imported generator sets are integrated with zero and ground. They must be removed when used. Otherwise, the transformer may jump if it is leakage protection. The ground wire of domestic generator sets is usually grounded separately on the ground, and the neutral wire and the neutral wire of the mains are connected together. The phase wire (three-phase wire) should be interlocked with switches to control the mains power and power generation to prevent the mains power from being added to the generator set.