Current transformer wiring inspection

- Oct 18, 2019-

(1) In order to find out whether there is a common fault such as disconnection or short-circuit fault on the side of the current transformer, the conductor connected to the voltage terminal of phase A of the electric energy meter and the conductor of the C-phase voltage terminal can be cut off successively, and the electric energy meter is The disc should be rotated. If the A phase voltage is broken and the disc does not rotate, it indicates that the current transformer C phase is disconnected or short-circuited. If the C-phase voltage is broken and the disc does not rotate, it indicates that the current transformer A phase is disconnected or short-circuited. If the cosg value on the spot is close to 0.5 (rational), in order to avoid misrecognition, the phase C voltage can be disconnected. In addition, the phase A voltage connected to the energy meter can be replaced by the phase C voltage. If the energy meter has a significant flip, it also indicates Phase A current is not broken, short circuit fault, etc.

(2) In order to distinguish whether the voltage transformer is reversed, the galvanometer can be connected to the other side of the current transformer, and the current is used to distinguish. For the star connection, when the voltage transformer is in one phase, When the optical reversal is reversed once or again, the phase current will be twice that of the other phase currents. If the current transformer optical rotation all reverse connection must make a vector diagram of the electric energy meter cooperative wiring, it can comprehensively distinguish.

(3) Resolve whether the current transformer is a grounding device and can be accurately measured with an ammeter. For accurate measurement, one side of the ammeter is connected to the terminal of the ungrounded device of the voltage transformer, and the other end touches the line of the current transformer. If the ammeter is marked as 100V, it indicates that the current transformer is grounded again. If the ammeter is marked as 0, it indicates that the current transformer has no grounding device.

(4) When the grounding device is determined to be appropriate, it can be accurately measured with an ammeter. Therefore, the galvanometer should be grounded with one terminal. The wires of the other terminal are respectively touched with the current quantity terminal of the electric energy meter. If the terminal is a grounding device, the ammeter should be unmarked, and the disk speed of the electric energy meter is not damaged; if the terminal If the device is not grounded, the ammeter is marked and the disk speed is also compromised.


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