Low-voltage grounding equipment is mainly used in low-voltage diesel generator sets, thermal power plants, coal production enterprises, starting and braking power and other resistance equipment. Here we talk about the role of the low-voltage grounding complete set of diesel generators working in coal production enterprises.
ENR-DR low voltage grounding kit is a resistance kit for grounding in a low voltage system. In order to improve the power supply quality of the low-voltage power supply system and reduce the power failure of the generator set caused by the occurrence of a grounding fault, the low-voltage power supply system in the main building of the power plant should be grounded with high resistance, which not only avoids the need to trip immediately when the single-phase grounding, but also reduces the probability of burning when the generator set is operated by using a fuse as a protective appliance.
In the past, the low-voltage system mainly used the direct grounding mode or the ungrounded mode. When a single-phase grounding fault occurs, the neutral voltage of the directly grounded system remains unchanged, but the system neutral current is too large, which is easy to break down the insulation and burn the neutral system. If the system adopts ungrounded mode, the generated overvoltage is N times the rated voltage, because the arc light and ferroresonance overvoltage makes the phase voltage of the non-fault phase rise several times, which poses a threat to the insulation and thermal stability of the generator set.
China’s “Coal mine electricity safety regulations” clearly stipulates: neutral point directly grounded transformer and generator are not allowed to directly supply power to the mine. In other words, the neutral point of the coal mine power grid is not allowed to be directly grounded. Originally, the arc suppression coil is mainly used for grounding, and with the follow-up of technology, the grounding resistance is mainly used.
When the neutral grounding resistance cabinet is installed and non-metallic grounding occurs, the current flowing through the ground point and neutral point is significantly reduced by the ground point resistance, and the non-fault phase voltage rise is also significantly reduced. The zero sequence voltage value is about 30% of the single-phase metallic grounding. Low-voltage complete equipment refers to the complete equipment used in the voltage class of 380V and below.
The diesel generator set is installed with a low-voltage grounding set, which extends the life of the diesel generator set and improves the working efficiency of the diesel generator set.
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Post time: Dec-17-2024