The installation direction of current sensor needs to be determined according to the type and wiring principle. For common current transformers, the installation direction is closely related to the direction of primary current, and the incoming line terminal (P1) and the outgoing line terminal (P2) need to be distinguished. The following is a detailed description:
Directional requirements of current transformers
The installation direction is determined by the direction of primary current: when the current flows in from the P1 terminal and flows out from the P2 terminal, the secondary current direction is S1→S2; if the current is reversed, the secondary current direction also needs to be reversed (S2→S1).
Same-name terminal rule: S1 and P1 are same-name terminals, and S2 and P2 are same-name terminals. If the primary current enters from P2 and flows out from P1, the secondary wiring needs to be adjusted to S2 connected to the incoming line and S1 connected to the outgoing line.
Typical connection method: It is generally recommended that the primary current enters from the P1 terminal, ensuring that S1 on the secondary side is the incoming line and S2 is the outgoing line to meet the polarity requirements of the meter or protection device.
Extended types of current sensors
Hall current sensor: Current is usually detected by magnetic induction. The wiring direction must meet the requirements of the magnetic field direction. For details, please refer to the implementation principle of the Hall effect.
Magnetic compensation current sensor: The primary magnetic field needs to be compensated by the secondary current. The wiring direction directly affects the compensation effect. The polarity needs to be determined according to the design manual.
Key scenarios for direction judgment
Electric meter measurement: Wrong direction will lead to measurement errors. The wiring sequence of S1/S2 must be strictly followed.
Relay protection: Scenarios such as differential protection are sensitive to the current direction, and differential wiring is required to ensure phase consistency.