Views: 0 Author: Site Editor Publish Time: 2025-07-01 Origin: Site
Power Carrier Modules Protect - Yint Electronic
Meter Smart Switch is a smart device that integrates multiple functions and is mainly used to control and monitor the switching status of the power system.
Power Carrier Module (PLC) is a device that uses power lines to transmit data signals, which is mainly used in the fields of power systems, smart homes and remote meter reading.Its main working principle is to modulate the data signal to the power line, transmit it to the receiving end through the power line, and then restore it to the original data signal through demodulation technology.The general environment will convert the power carrier signal into RS232 or RS485 interface.
Transient high voltage (surge) may occur in the power grid due to lightning strikes, equipment start/stop (e.g. motors, transformers) or line faults, and the high voltage may penetrate the semiconductor devices of the smart switches (e.g. MOSFETs, relays) or the communication chip of the PLC module.Also, short-circuiting of loads, internal equipment faults or wiring errors may lead to abnormally high currents, resulting in heating of wires, burning of components, and even fires.Therefore, it is necessary to protect them.
1.PLC module design protection circuit:
T1 transformer is 1:1 transformer; C1 safety capacitor is recommended to choose 10nF safety capacitor; primary bidirectional TVS protection tube (D1/D2) is mandatory, recommended SMBJ6.0CA; PLC signal access point on the LN line needs to be in the back of the varistor (RV1), varistor is recommended to be 20D821K. PLC signals need to be connected to the back of the series of the two differential-mode inductance (L1/), and the PLC signal is connected to the back of the two differential-mode inductance (L1).L2) should be connected behind the PLC signal to isolate it from the power supply of the whole machine, and the inductance value of the differential mode inductor is recommended to be 50~100uH.
2. 220VAC AC power supply protection circuit:
Recommended Devices:
Varistor: 14D561K, Gas Discharge Tube: 2R600L
Advantages: simple circuit, one level of protection, composite symmetrical circuit, common mode, differential mode full protection
3.RS485 circuit protection
Recommended devices:
Gas Discharge Tube GDT: 3R090L-5*7.6 3R090S-5*7.6 3R090L-8*10 3R090S-8*10
Transient suppression diode TVS: SMBJ6.5CA SMBJ7.0CA
Common mode filter: Common mode filter recommended CMZ4532A-501T or CML4532A-510T, can also be connected in series with a resistor (more than 2 ohms) or magnetic beads per line, or can not be used
Grounding design: Independent ground plane, TVS ground terminal is directly connected to the metal casing.
4.RS232 circuit protection
Advantages and disadvantages of the solution: very high lightning protection level, use of TVS diodes, high parasitic capacitance, some impact on the rate.
5. Carrier-coupled signal protection programme:
The use of semiconductor discharge tubeP0300SC, which has ultra-fast response speed, stable IH value, minimal signal attenuation, and strong continuous anti-interference capability, ensures sufficient surge capacity while guaranteeing signal integrity.
