METHOD AND APPARATUS FOR RESUMPTION OF NORMAL OPERATION OF A HIGH-VOLTAGE D. C. TRANSMISSION LINE

Method and Apparatus for resumption of normal operation of a High Voltage Direct Current transmission line after a malfunction in one of two stations connected to a HVDC transmission line. A control angle of approximately 90 degrees is run up in the previously malfunctioning station in accordance with a given function, thus creating an indication quantity at the D.C. voltage connections of the other station, which is detected as the earliest possible information on the start of the external station and also enables the run-up of the control angle in accordance with a given run-up function, with the two run-up functions representing precalculated, compatible, actual substitute values for the fault indication quantity caused by the respective other station. At the end of the run-up, the run-up functions are switched over to measured values of fault indication quantities, thus attaining stable control with short run-up and control times.