Signal Attenuation of Data Transmission by Power Lines

Using a Power Line as a Communication Channel. Ways to Reduce Distortion  in the Transmission of Signals over Power Lines. Plc Technology

Abstract

Power Line Communication (PLC) technologies are actively developing and becoming more and more in demand all over the world. They are used in the automation of technological processes, the organization of video surveillance systems and even to control a "smart" home.

Research in the field of data transmission using the power grid has been going on for a long time. Once upon a time, the use of PLCs was hampered by low data transfer rates and insufficient immunity from interference. The development of microelectronics and the creation of modern, and most importantly, more efficient processors (chipsets) made it possible to use complex modulation methods for signal processing, which made it possible to significantly advance in the implementation of PLC. However, only a few specialists still know about the real possibilities of communication technology over the power grid.

The reliability of data transmission is greatly influenced by interference from various electrical appliances, fluorescent  lamps, etc., which interfere with the wires. The strongest influence of impulse noise arising from the operation of electric motors, welding equipment and microwave ovens. However, reliable methods of encoding and encrypting data used in modern PLC technologies provide not only a high level of reliability in the transmission of information, but also its protection from unauthorized access. In addition, when organizing communication, electromagnetic compatibility must be ensured, i.e. it is necessary to reduce the spurious electromagnetic radiation arising from the process of data transmission.

Today PLC finds wide practical application. Due to the fact that the technology uses the existing power grid, it can be used in the automation of technological processes for linking automation units via electric wires (for example, city electricity meters).

The widespread use of low-voltage electrical networks 0.22 ... 0.38 kV, the absence of the need to carry out expensive work on the construction of trenches and punching walls for laying cables stimulate an increased interest in these networks as a data transmission medium.

Often, PLCs are used to create video surveillance systems or a local area network in small offices, where the main requirements for the network are ease of implementation, device mobility and easy scalability. At the same time, both the entire office network and its individual segments can be built using PLC adapters. It is often necessary to connect a remote computer or network printer located in another room or even at the other end of the building to an existing office network - using PLC adapters, this problem can be solved in a few minutes.

In addition, PLC technology opens up new opportunities for implementing the idea of a "smart" home, in which all  consumer electronics must be tied into a single information network with the possibility of centralized control.

The article discusses the basic principles of using power lines as a communication channel, and ways to build such net works. Also, it offers to get acquainted with the main problems of this technology and ways to solve them.