Electrical Technology 2020-3-9
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True or False question: Please answer whether it is correct or incorrect. 3 points for a correct answer, 2 points for an incorrect answer, and 5 points for a detailed explanation of the reason. When a cable-type zero-sequence current transformer is used for grounding protection, the grounding wire at the cable terminal must be passed through the core hole of the zero-sequence current transformer before being grounded.
Error. When the cable grounding point is below the zero-sequence current transformer, the ground wire should be grounded directly ； When the grounding point is above the zero-sequence current transformer, the grounding wire should pass through the zero-sequence current transformer for grounding. At the same time, the metal shielding layer and grounding wire of the cable segment from the cable terminal to the zero-sequence current transformer should be insulated from ground, with an insulation resistance to ground of not less than 50 kΩ.