Circuit arrangement for limiting the overvoltage of an excitation winding of a synchronous machine having rapid de-excitation

摘要

A circuit arrangement for de-exciting an excitation winding of a synchronous machine in the event of a fault, including a control circuit for controlling a current flow through the excitation winding, it being possible to apply a positive control voltage to the excitation winding for excitation and a negative control voltage for rapid de-excitation, and including a protective circuit which is parallel-connected to the excitation winding and which does not permit a current flow over the protective circuit in the event of rapid de-excitation and which forms a current path for limiting the voltage and de-exciting the excitation winding if at least one connecting line between the control circuit and the excitation winding is interrupted.

主权项

1. A circuit arrangement for de-exciting an excitation winding of a synchronous machine in the event of a fault, comprising:
a control circuit for controlling a current flow through the excitation winding, wherein a positive voltage is appliable to the excitation winding for excitation and a negative control voltage for rapid de-excitation; and a protective circuit which is parallel-connected to the excitation winding, which does not permit a current flow over the protective circuit in the event of rapid de-excitation, and which forms a current path for limiting the voltage and de-exciting the excitation winding if at least one connecting line between the control circuit and the excitation winding is interrupted; wherein the protective circuit has a free-wheeling branch which includes at least one series connection of a free-wheeling diode and a controllable switching element, wherein the switching element is a transistor or a thyristor, and a control signal for the switching element is generated with the aid of a voltage divider which is parallel-connected to the free-wheeling branch, wherein the voltage divider has a resistor branch, and wherein a diode branch is parallel-connected to the resistor branch and includes at least one series connection of at least one Zener diode and at least one resistor.