The Power Line Communication Base On Catenary

Power line communication is one of the bases of power communication network, it uses power line as communication media for data transmission and information exchange. Modern power line communication is in combination with microelectronics, digital technology, digital signal processing and micro-computer, so that the power line carrier communication skills go into a new phase. Carrier communication which is in accordance with the theory of frequencies move and frequencies division, modulate the original signal to one or more carrier, move to a different line transmission band, and then sent to the transmission lines to achieve multiple communication.Orthogonal Frequency Division Multiplexing(OFDM) is a critical technology for the realization of broadband power line communication. OFDM utilizes several sub-carriers which are orthogonal with one another to transmit information, thus, the utilization of frequency band is enhanced greatly and the frequency selective fading and time variation in power line channel can be overcome effectively. The reliable data communication with high speed has been realized.The paper describes that the way to communication use of the catenary by power line communication. The purpose of this thesis is data of control signal can be transmitted from the master control locomotive to the sub-locomotive through the overhead contract system as in the locomotive lo-control system. When the locomotive cross over mountain in the region, tunnels and turning, the wireless transmission of signals may be blocked and can not be reliably transmitted. However, if the use of power line transmission signals, so long as the pantograph and catenary linked to stability, the signal can be coupled to the power line for transmission, there is no obstruction problem. Therefore, power line carrier communications and wireless signal transmission can be combined to achieve the stability of locomotive control signal transmission.In this paper, it analyzes power line interference and attenuation, introduces the electromagnetic affection towards data communication that caused by the 25 kilo voltage overhead contract system, chooses OFDM is to be the usable technology, analyzes its feasibility and proposes structure of the system. At last the experiment realized data transmission based on 220 voltages in our lab, demonstrates the reliability of communication.