Three-phase watt-hour meter through current transformer wiring schematic - Database & Sql Blog Articles

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1. The meter's rated voltage must match the power supply voltage, and the rated current should be 5A.

2. Connect the wiring in the correct phase sequence to ensure accurate readings.

3. For current transformers and LQG type devices, the accuracy should not be less than 0.5. Ensure correct polarity is used for the current transformer.

Three-phase four-wire (three-phase three-element) watt-hour meter through current transformer wiring schematic

Schematic diagram of three-phase three-wire (three-phase two-component) watt-hour meter through current transformer wiring

4. The secondary wiring should be made of insulated copper wire without any joints. The cross-sectional area should be at least 1.5mm² for the voltage circuit and 2.5mm² for the current circuit.

5. Arrange the secondary wires neatly, and mark both ends with loop labels and numbers for easy identification.

6. When the metering current exceeds 250A, connect the secondary circuit through a special terminal. The order of each phase conductor on the terminal should follow a consistent pattern, such as from top to bottom or left to right, labeled as U, V, W, N.

7. Three-phase four-wire active energy meters (DT type) are designed to measure active power for both symmetric and asymmetric loads in a four-wire system. Three-phase three-wire active energy meters (DS type) are used specifically for three-wire systems, whether balanced or unbalanced.

For example, if the load current is 361A in a three-phase four-wire system, an active energy meter connected via a current transformer can accurately measure the active power.

A suitable option could be the DT8 380/220 3×5A active energy meter, paired with an LQZ-0.5 400/5 current transformer for proper scaling and measurement.

Always ensure that all connections are secure, and the equipment is installed according to local electrical codes and safety standards. Regular maintenance and calibration are also recommended to maintain accuracy and reliability over time.