At what power or current level does an electricity meter require a current transformer?
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An electric energy meter may be connected in series in the circuit; I need to know what current or power level is required before using a current transformer to connect to the energy meter
It mainly depends on the input current of the meter; generally, currents below 100A seem to not require a transformer
Most three-phase four-wire electricity meters used in industry are rated at 5A, while those for agricultural, commercial, and household use have a maximum rating of 3*100A
Is it correct that meter meters with current transformers are used only for currents above 100A?
Ahaha, let me give a brief explanation about this sea friend! Generally, the models of single-phase electronic electricity meters are standardized nationwide; the maximum current rating is 80A. There are usually 4 models: 5 (20)A, 10 (40)A, 15 (60)A, and 20 (80), which are referred to as 4-times electricity meters ； The specifications for three-phase electricity meters: Three-phase 4-wire direct-type wattmeters generally have the following specifications: DT862-15(60)A, direct-connected type ； DT862-30(100)A Direct-type ； DT862-20(80)A Direct-type ； DT862-5(20)A Direct-type ； DT862-10(40)A Direct-type ； The value in parentheses indicates the maximum allowable load current. Therefore, the maximum current for direct-reading meters in single-phase and three-phase systems is different. For large industrial petrochemical plants, the electricity meters used are related to the process requirements of the plants as well as the energy management standards of the factory. For process units, petrochemical standards require that motors with a power of 37 KW or more, or those in processes where current monitoring is necessary, be equipped with ammeters (which means separate current transformers for on-site display are required). Taking into account the scale of the process unit, current transformers with a secondary current of 1 A are typically used to meet the requirements for remote transmission and display ； For the output cabinet, either a 1A or 5A secondary current transformer can be used (for energy consumption monitoring and display in MCC systems).