When the iron core of a power transformer is grounded at two or more points, circulating current will be generated inside the iron core, causing local overheating and even local burning of the iron core, melting the grounding plate, and causing the iron core potential to float, resulting in discharge faults and seriously threatening the operation of the transformer. Therefore, real-time monitoring of the grounding current of the transformer iron core and clamps is particularly important.

The TZY-PCT2000 power frequency current monitoring device consists of sensors, data acquisition, processing modules, and communication modules. It is used to collect the power frequency grounding current signal of power transformers and can achieve live inspection or long-term outdoor on line monitoring of the grounding current signal of the iron core and clamp of power transformers. The sensor adopts an open design, and the shell is shielded with multiple layers, which has strong anti-interference ability and high accuracy. The assembly method is screw connection, which can quickly disassemble and assemble under the condition of live operation of the transformer, and is simple and easy to use.

The TZY-PCT2000 power frequency current monitoring device digitizes the grounding current signal through the RS-485 bus and uploads it to the backend monitoring host of the substation according to the MODBUS/RTU standard communication protocol.

3.1 Working conditions:

Operating environment: -40~85 ℃

Relative humidity: 5-95% (without condensation)

Atmospheric pressure: 80kPa~110kPa

Protection level: IP65

Installation method: Open mouth

3.2 Equipment size:

Dimensions (width x height x depth): 144 x 82 x 134mm

Opening size 50 × 20mm

Weight: 2.3kg

3.3 Power frequency grounding current signal:

Power supply: DC 24V, 50mA

Measurement range: 2mA~12A

Full range nonlinear error: 5%