Research on Safe Grounding Protection for Small Resistance Grounding System Considering Distributed Generation

doi:10.16628/j.cnki.2095-8188.2024.03.011

Abstract

Abstract:

Excessive residual voltage and step voltage in the case of single-phase "false power supply" of the neutral point grounding system with small resistance may pose a threat to the personal safety of operators,especially in the trend of large-scale connection of distributed generation supplies.Firstly,the grounding mode of grounding electrode and related soil characteristics are analyzed from the safety basis of grounding measures.The corresponding typical soil grounding resistance calculation method is provided.Secondly,based on PSCAD/EMTDC and Anysy software,the operating grounding model of small resistance grounding system with distributed power supply is built to analyze the problems of residual voltage and excessive step voltage.Finally,combined with the actual field verification,the effective grounding safety measures for maintenance operation are put forward to provide useful reference for relevant departments.

Key words: small resistance grounding system, distributed generation, residual voltage, step voltage, safe operation

CLC Number:

TM774.4

WANG Chengjie. Research on Safe Grounding Protection for Small Resistance Grounding System Considering Distributed Generation[J]. LOW VOLTAGE APPARATUS, 2024, 0(3): 66-70.

Figures/Tables 14

References 14

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土壤电阻率/Ω?m	工频接地电阻/Ω	土壤电阻率/Ω?m	工频接地电阻/Ω
100及以下	10	1 000~2 000	25
100~500	15	2 000以上	30
500~1 000	20	—	—

名称	电阻率/ (Ω·m)	各环境电阻率范围/(Ω·m)
名称	电阻率/ (Ω·m)	较湿多雨	干燥少雨
陶土、黏土	10	5~20	10~100
泥炭、沼泽地	20	10~30	50~300
黑土、田园土	50	30~100	50~300
砂质黏土	100	30~100	50~300
黄土	200	100~200	50~300
砂、砂砾	1 000	25~1 000	1 000~2 500
砾石、碎石	5 000	—	—
多岩山地	5 000	—	—
花岗岩	2×10⁵	—	—

距离/m	跨步电压/V	距离/m	跨步电压/V
0~1	5 049.930 0	4~5	76.917 8
1~2	587.638 9	5~6	58.665 1
2~3	166.893 4	6~7	44.866 7
3~4	103.289 6	7~8	34.324 4

测试地点	接地极埋深/m	接地阻抗/Ω	接地电阻/Ω
17#杆草坪	0.6	218.80	218.80
17#杆草坪	0.7	205.20	205.20
17#杆草坪	0.8	198.10	198.10
17#杆草坪	0.9	194.80	194.70
17#杆附近红土	0.4	85.43	85.32
17#杆附近红土	0.6	69.46	69.34

测试地点	改善方法(埋深/m)	接地阻抗/Ω	接地电阻/Ω
17#杆草坪	双重接地极(埋深0.6)	151.30	151.30
17#杆草坪	双重接地极(埋深0.7)	146.30	146.20
17#杆草坪	加入盐水(埋深0.6)	118.30	118.30
17#杆草坪	加入盐水(埋深0.7)	108.50	108.50
17#杆草坪	加入盐水(埋深0.8)	104.20	104.10
17#杆附近红土	加入盐水(埋深0.6)	35.42	35.28