How does poor grounding of the intelligent low-voltage monitoring unit affect the monitoring data?

Poor grounding causes reference potential drift, affecting the accuracy of monitoring data. Specific impacts include: voltage measurement error exceeding 2%; increased current phase error; and false alarms in leakage current detection. Solutions include: using an independent grounding stake with a grounding resistance of less than 0.2Ω; employing shielded twisted-pair cable in the monitoring circuit with single-point grounding of the shielding layer; using an independent ground plane on the PCB for the monitoring circuit, connected to the main ground via a PBZ1608A-102Z0T ferrite bead; and using an ISO7240C isolation amplifier for isolated sampling. Through optimized grounding, the monitoring data error is reduced to less than 0.5%, meeting the IEC 61869 0.5 accuracy requirement.