Most fire prevention Grounding Grid Accident

Prevention of grounding accidents

1 the design of grounding should seriously implement the grounding of exchange electrical assembly (dl/t621 1997) and other relevant regulations, with emphasis on avoiding rust after the appearance is free of paint. The following requirements:

2 according to the change of regional short-circuit capacity, the thermal stability capacity of grounding assembly (including equipment grounding downlead) should be checked, and the reform of grounding assembly should be stopped according to the change of short-circuit capacity and the corrosion degree of grounding assembly. For ungrounded, arc suppression coil grounded, low resistance or high resistance grounded parts in the substation, the thermal stability capacity of the grounding assembly must be checked according to the two-phase grounding at different points

3 in the engineering design, we should accept the experience of grounding disturbance. The design unit should put forward an improved and perfect grounding design, and the construction unit should strictly stop the construction of the new Mar plant according to the design. For perfect grounding design, the construction unit should stop construction in strict accordance with the design

4 during infrastructure construction, the earth can be backfilled only after the reserved equipment, measures and grounding downleads are confirmed to be qualified (official written records) and the buried works must be accepted by the supervision unit and the supporting unit, and the loop resistance between the two recent grounding downleads should be measured separately. The test results are the necessary content of the acceptance data, and all of them should be submitted to Party A for filing when completed

5 the welding quality and grounding test of grounding assembly should be properly specified. The connection between various equipment and the main grounding must be reliable, and the expansion grounding and the original grounding should be multi-point connection

6 the key substation with serious corrosion of grounding assembly should adopt the grounding of copper materials

7 for the grounding in areas with high soil resistivity, when the grounding resistance is difficult to meet the requirements, there should be perfect voltage equalization and isolation methods before it can be put into operation

8 the neutral point of the transformer shall have two grounding downleads connected to the main grounding at different addresses, and each grounding downlead shall meet the requirements of thermal stability. The primary equipment and equipment structure should have two grounding downleads connected to the main grounding at different addresses. At present, the market share of CFRP reaches 90%, and each grounding downlead should meet the requirements of thermal stability. The connecting lead should be easy to stop inspection on schedule. It is also possible to test in other thermoplastic polymer matrices

9 the continuity detection task of grounding assembly downlead should be stopped once a year. Analyze and compare the previous measurement results to determine whether it is necessary to stop excavation and processing

10 in order to prevent the abnormal operating conditions of Lingding ungrounded parts and high power frequency overvoltage in the effective grounding parts, the rod gap protection method should be adopted for the neutral overvoltage protection of LLO ~ 220kV ungrounded transformer. For 110kV transformers, when the strike withstand voltage of neutral insulation is ≤ 185kv, metal oxide arresters should also be paralleled beside the gap, and the gap spacing and arrester parameters should be checked together

11 the experimental requirements for grounding assembly in the preventive experimental code for electric power equipment (dl/t596 1996) should be fulfilled. At the same time, the connection environment between various equipment and grounding should be tested. It is strictly forbidden for the equipment to run when it falls to the ground