| 摘要 |
The invention concerns transmission of electrical energy. It starts from a method of controlling a transmission system for high-tension direct current with a rectifier 6 and an inverter 12 of the type with controlled gates, and it includes measures for reducing the reference value of the current put out from the rectifier to the inverter in direct dependence on the value of the difference between a predetermined value and the minimum value for the margin of commutating of the inverter's gates, when this minimum value for the margin of commutating of the inverter's gates falls below a predetermined value, whereupon the reference value of the current is set to be above or equal to the minimum permitted value. A regulating arrangement for operation of such a transmission system includes a measuring element 26 for generating a signal which corresponds to the minimum of the margin of commutating for the inverter's gates and a signal shaping element 20 for the reference current, which contains a subtractor 35 with inputs 39, 40 connected to the output of the measuring element 26 and to a reference signal source 53, respectively, a limiter 36 which has its input connected to the output of the subtractor, an additional subtractor 37 with inputs 41, 42 connected to the output of the limiter 36 and to a second reference source 54, respectively, and a minimum signal limiter 38 with its input connected to the output of the additional subtractor 37. The output signal for the minimum signal limiter 38 is fed to a control device 16 for adjustable regulating of the control angles for the rectifier gates. The invention can be used for protection of the gates in transmission systems for high- tension direct current in event of malfunctions. <IMAGE> |
