DL5153-2014 Large-scale thermal power plant power supply design technical regulations Article 8.2.3 of the large thermal power plant and the second low voltage feeder of 8.7.1 and the motor below 100KW are protected by the phase-to-phase short circuit as the grounding protection. When the sensitivity is not satisfied, it should be installed separately. Ground short circuit protection. Since sensitivity is difficult to judge and control investment needs, most of them do not have zero sequence protection. After the operation, the feeder below the secondary bus or the single-phase grounding of the motor appears, and the fault of the first-level bus feeder zero-sequence protection is skipped.
SMR-LD2 phase-to-ground short-circuit monitoring and protection device is suitable for 400V TN system of power plant, coal, steel, textile, etc. It can solve the problem that small resistance grounding, plastic case switch and thermal relay do not work in MCC line, causing large-area power failure caused by PC over-level trip. . The phase-to-earth short-circuit monitoring and protection device continuously monitors the zero-sequence CT current of each circuit, satisfies the condition and then trips after the alarm, and cuts off the power supply fault line to protect the equipment and avoid huge economic losses caused by the over-the-counter trip and power failure.
1) Real-time monitoring
2) Secondary warning three-level trip function
3) High sensitivity small size zero sequence current transformer