·         120-degree phase angle between every two phases of the three phase alternating current. When the three phases A, B and C are separate communication channels, one whole transformer area can be divided into three smaller transformer areas and power computation and phase splitting management can be conducted so as to achieve the balance among three phases; In the 50 Hz low voltage electricity network, it uses the 3.3ms time slice of three phases’ zero - crossing point to transfer the carrier signal, all the 20ms periodic is utilized as a result of which the communication efficiency is high.

·         Within a power supply cycle of the AC power supply, the AC voltage has two zero crossing points. Low voltage electricity network has the qualities of high and stable impedance and low noise at the voltage crossing zero point under the condition of 421 KHz carrier frequency. The noise of low voltage electricity network decreases as frequency increases.

·         Differentiation of phases: The three phases A, B and C are separate communication channels respectively and they can be automatically determined by smart energy meters, which can provide accurate evidence for the load adjustment of transformer areas.

·         Synchronization of systems: Each communication node is able to cross the zero point according to the power frequency of low voltage network. The reference source of communication system synchronization can guarantee the time synchronization of communication system.

·         To analyze the noise spectrum of low voltage network, properly chose the carrier frequency and communication period is the key to eliminate the noise effects to the carrier communication. It is a world leading technology in the PLC communication module.

·         The impedance analysis of low voltage network has optimized the feeder mode of carrier signal, and achieved universal application in different quality low voltage network. The particularity of impedance variation of low voltage network is its unique characteristics as a new type of communication media, which makes it different from all the other media, while which is also a difficulty to realize the reliability of low voltage carrier communication.

The solutions developed according to above PLC technology characteristics have successfully settled the problems which the other power line carrier products failed, such as the frequency converter pump noise of secondary water supplying in high buildings, the charger noise of electric car which badly affects the power line carrier communication, the reliability of power line communication in complicated transformer areas etc.

Qingdao Topscomm Communication Co., Ltd. has achieved the world leading position in the field of R&D of power line communication technology.