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. Ensure that the wiring follows the correct phase sequence.

3. For current transformers and LQG type devices, the accuracy should not be less than 0.5. Proper polarity must be observed during installation.

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 wires should be insulated copper cables without any joints in between. The cross-sectional area for the voltage loop should be at least 1.5 mm², while the current loop should be no less than 2.5 mm².

5. The secondary lines should be neatly arranged with clear markers on both ends, including loop numbers and labels for easy identification.

6. When the metering current exceeds 250A, the secondary circuit should be connected via a dedicated terminal block. The phase conductors on the terminal block should be arranged from top to bottom or left to right as U, V, W, N.

7. Three-phase four-wire active energy meters (DT type) can 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 for three-wire systems only, whether balanced or unbalanced.

For example, if the load current is 361A in a three-phase four-wire system, an active energy meter connected through a current transformer would be suitable for measuring active power.

A recommended model could be the DT8 380/220 3×5A active energy meter. To match the current level, use an LQZ-0.5 400/5 current transformer.

It's important to ensure all connections are secure, properly labeled, and follow local electrical codes and safety standards. Regular maintenance and calibration of the meter and current transformers will help maintain accuracy and reliability over time.