摘要 |
<p>The invention relates to a system and a method for limiting the voltage in a converter station supplied with a voltage, connected between a direct-current line and an alternating-current line, the station including at least two valves per phase of the alternating-current line, which in turn each include at least one semiconductor element with breaking capacity and a semiconductor device in the form of a diode, connected to the former in anti-parallel. The station also includes at least two capacitors that define the voltage of the direct-current line, as well as: in each one of the capacitors, a switch connected to the earth, which discharges the capacitor and is controlled by a control means; and a control means that opens and closes the switches depending on the voltage between the capacitors: if the voltage between the capacitors exceeds a certain threshold, the switch connected to the capacitor receiving the higher voltage is closed, discharging same until the voltage of the two capacitors is the same, in which case the control means opens the switch again.</p> |