Why the underground power system is a neutral point ungrounded system to use insulation monitor
The so-called neutral grounding power supply method refers to connecting the neutral point of the transformer to the ground through the metal grounding body. Conversely, the neutral point is insulated from the earth, and the neutral point is not grounded.
When the power grid is grounded, the neutral grounding system is a single-phase short circuit. The short-circuit point will generate a large arc. In a mine with gas, it will cause gas explosion. When the short-circuit current flows in the earth, it will easily cause electricity. Explosion accident. The neutral point ungrounded system only needs to maintain a high insulation resistance to ground, and the grounding current is relatively small. In addition, in a power supply system where the neutral point is not grounded, if the human body touches one phase of the live conductor, the current passing through the human body passes from one phase of the power grid to the ground, and then through the other two relative insulation resistances and capacitance to the ground. Returning to the other two phases of the power grid, due to the high insulation resistance to ground under such conditions, the excessive current is limited, and the electric shock to the human body is small. In the neutral point grounding power supply system, when a person touches a phase charged body, the phase voltage of the human body across the power grid, the current flowing through the human body far exceeds the limit safe current. It is very dangerous for people.
Due to the harsh environment of the mine and the high requirements for safe electricity use, the safety regulations stipulate that the insulation monitoring instrument should be installed at the same time using the neutral point ungrounding method in the underground power distribution system and the open-pit mining field. When the grid-to-ground insulation resistance decreases, an alarm signal is issued. .
After several generations of development, Ganbo Electronic YNY series insulation monitors have been monitored from low-voltage insulation monitoring to high-voltage insulation monitoring. The full coverage of AC and DC insulation monitoring can meet the requirements of different working conditions of customers. At present, the application of insulation monitors of our company has been spread all over the country. It has been applied in dozens of large enterprises and projects such as Wu Mining Group, China Metallurgical Group and Baicheng Mining.
The Insulation Monitor is designed for use in IT systems to monitor real-time insulation resistance of ungrounded systems and to signal when the system fails for the first time.
Dongguan Ganbo Electronic Technology Co., Ltd. specializes in R&D and production of insulation monitors. Its YNY series of products have many specifications and can be applied to all kinds of ungrounded power grids. It can completely replace imported insulation monitors and has gradually become a new benchmark for domestic insulation monitors.
