Mining Industry Insulation Monitoring

SKIM400 insulation monitoring device is used on Mining industry

Due to the harsh mining environment and high requirements for safe electricity use, for safety reasons, the grounding form of the low-voltage distribution system in the mine underground is adopted as per regulations using an IT system. The IT system is a system where the neutral point of the power supply is not grounded, and the exposed conductive part of the electrical equipment is directly grounded (PE line).
The characteristic of IT systems is that when the first ground fault occurs, the ground fault current is only the capacitance current of the non fault phase to ground, which is very small. The voltage of the exposed conductive part to ground does not exceed 50V, and there is no need to immediately cut off the fault circuit, thus ensuring the continuity of power supply. But at this time, the non fault phase to ground voltage will increase by 1.732 times, which increases the requirement for line withstand voltage; Once a secondary grounding occurs, it constitutes a dangerous phase to phase short circuit, so insulation monitoring devices must be installed to timely eliminate hidden dangers in the event of the first grounding.
For underground environments represented by coal mines, during the mining process, due to the small working space, long vertical depth, and many adverse factors such as humid air, dust, dripping water in tunnels, and water accumulation, it is easy to cause cable and electrical equipment aging and insulation resistance decline, resulting in frequent insulation strength reduction, single-phase leakage or single-phase grounding faults of underground equipment and cables. If not dealt with in time, it may further develop into phase to phase short circuits. Therefore, underground workers are more susceptible to the danger of electric shock than in normal environments, and may also lead to explosions of gas and coal dust.
Therefore, in order to ensure the normal operation of underground production and protect the safety of underground personnel, the mining industry has formulated many relevant standards and specifications, and specific provisions have been made for the installation of insulation monitoring devices in IT systems.
1. The live part of the power supply end of the distribution system should not be grounded or grounded through high impedance, and the fault current should not exceed 5A when an impedance negligible fault occurs for the first time between the phase conductor and the exposed conductive part of the distribution system.
2. The distribution system should not lead out N lines;
3. The insulation monitoring instrument has anti-interference ability and stable operation under harsh working conditions
SKIM400 has mature applications in various low-voltage distribution systems in mines.