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The technology for diagnosing singlephase grounding faults in mediumvoltage distribution networks is of significant importance for enhancing the operational safety and economic efficiency of the system. In light of the current scenario where a large number of distributed generation sources are connected to the distribution network, this study analyzes the impact of distributed generation on singlephase grounding fault currents. It proposes a method for identifying the types of singlephase grounding faults and introduces a fault section location technique utilizing harmonic injection from adjustable arc suppression coils. Upon the occurrence of a singlephase grounding fault in the distribution network, the type of fault is first analyzed based on the characteristics of the zerosequence voltage and phase voltage. Subsequently, the filtering device of the adjustable arc suppression coil is temporarily blocked, allowing the harmonic current from the coil to be briefly injected into the grid. The system's FTU and DTU components analyze the third harmonic content in the zerosequence current. The presence of the third harmonic is used as a criterion to accurately determine whether the detection point is on the fault path, thereby achieving fault section location. A 10 kV distribution network simulation model under various grounding conditions was constructed and analyzed using EMTP/ATP software. The simulation results demonstrate that the aforementioned method effectively reduces the grounding current and achieves a section location accuracy of over 95%. This validates that the proposed method is suitable for both metallic grounding and grounding through transition resistance, meeting practical application requirements.
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| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |
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