Research on the encoding and decoding of the valve base electronics for direct current

By studying the ±80 kV direct current transmission project in Jeju Island, Korea, this paper proposes a method of multiple-pulse encoding and decoding for the valve basic electronic(VBE) of high voltage direct current transmission systems though the problem of immutable pulse width, poor anti-jamming of decoding and low communication efficiency. The problems of immutable pulse width of encoding and poor anti-jamming of decoding are solved in VBE by using the methods of edge trigger of high frequency clock and deferment of judgment. Considering the problems of the five-pulse encoding and decoding of SIEMENS, the paper solve the compatibility of VBE for different company by using the method of pulse width mutable. By studying the statistical validity of U_NEG, this paper proposes the U_NEG adaptive decoding strategy which can improve the test efficiency of decoding and simplify the logical structure of the decoder. The experiments results show that, the method of multiple-pulse encoding and decoding can achieve reliable triggering and on line monitoring of thyristor valve and improve the efficiency of VBE communication. For example, the communication efficiency between VBE and TE is increased by 30%-50%.