Research On Outbound Signal Of TWACS For Distribution Networks

Two Way Automatic Communication System(TWACS)which appears in U.S.A. in 1990s is a communication system based on the power distribution network. The distinguishing feature of this system is that it can achieve the communication with signal striping over distribution transformer , without any trunk equipment. Compared with the most power line communication methods such as Power Line Carrier (PLC) and Spread Spectrum Carrier(SSC),the system has a lot of advantages such as inexpensive cost,simple implementation,long transmission distance,strong anti-interference capability and so on.After researching on the principles and the construction of TWACS totally and systematically,Signal modulation principle and transmission procedure are discussed in detail in this paper,the transmission characteristics and modulation of outbound signal are achieved finally,and Simulink verifies some theories,which demonstrated TWACS is also feasible in China. The principles of TWACS fitted by China are perfected. According to the earth-grounding mode for distribution networks in China,modulating signal and detecting signal are quite different from those in the original theories.This paper sums up the existing methods of the outbound signal demodulation,and in connection with the problem for the present demodulation methods,which is traditional method of signal demodulation has lower accuracy rate and the use of wavelet has higher recognition rate but algorithmic complexity,a reformative technique based on mathematical morphology is developed in this paper ,which can be implemented with micro controller for the simple algorithm and small amount of computation. This method succeed in solving modulation signal recognition issues in high-noise envirment,improve reliability of TWACS and has some practical value.This study greatly contributes to perfect TWACS theory adapted for China,and the promotion of this technique.