Control arrangement

1. A control arrangement for a circuit breaker station including a plurality of circuit breakers, voltage measuring devices for measuring bus bar voltages, current measuring devices for measuring currents through the circuit breakers, and, for each circuit breaker, a circuit breaker position indicating device for indicating the position of the circuit breaker, the control arrangement comprising:

a central control system for the overall control of the circuit breaker station, the central control system being, during use, connected to the voltage measuring devices, current measuring devices, and circuit breaker position indicating devices to obtain measured voltages, currents, and circuit breaker positions; and

for each of the circuit breakers, a circuit breaker operating unit connected, during use, to the central control system to obtain switching instructions, and to the respective circuit breaker to control the operation thereof, wherein

the central control system and the circuit breaker operating units have each a local clock, wherein all clocks are synchronized with one another;

the central control system is, during use, arranged to calculate a point of time for switching each of the circuit breakers based on the obtained measured voltages, currents, and circuit breaker positions, and earlier operating times for the circuit breaker, and to send said point of time in a switching instruction to said circuit breaker operating unit; and

each of the circuit breaker operating units is, during use, arranged to switch the circuit breaker, to which it is connected, at the point of time which is received in the switching instruction from the central control system.

2. The control arrangement of claim 1 wherein

the central control system is, during use, arranged to calculate a point of time for closing each of the circuit breakers based on the obtained measured voltages, currents, and circuit breaker positions, and earlier operating times for said switching operations, and to send said point of time in a circuit breaker closing instruction to said circuit breaker operating unit; and

each of the circuit breaker operating units is, during use, arranged to close the circuit breaker, to which it is connected, at the point of time which is received in the closing instruction from the central control system.

3. The control arrangement of claim 1 wherein at least one of the circuit breaker operating units is, during use, arranged to switch the circuit breaker, to which it is connected, to connect or disconnect an ac harmonic filter, a shunt capacitor bank, a shunt reactor, a transformer, or a transmission line.

4. The control arrangement of claim 1 wherein at least one of the circuit breaker operating units is, during use, arranged to switch the circuit breaker at voltage zero crossing.

5. The control arrangement of claim 1 wherein the central control system and the circuit breaker operating units are connected via a process fieldbus system.

6. The control arrangement of claim 5 wherein said process fieldbus system is an IEC61850 system, optionally provided with precision time protocol, or an EtherCat system.

7. The control arrangement of claim 1 wherein the circuit breaker operating units are each an TED or an I/O board.

8. The control arrangement of claim 1 wherein the circuit breaker operating units are each arranged within the circuit breaker to which it is connected, in a junction box, or in a control room.

9. A circuit breaker station comprising the control arrangement of claim 1 .

10. An HVDC system comprising the circuit breaker station of claim 9 .

11. The control arrangement of claim 2 wherein at least one of the circuit breaker operating units is, during use, arranged to switch the circuit breaker, to which it is connected, to connect or disconnect an ac harmonic filter, a shunt capacitor bank, a shunt reactor, a transformer, or a transmission line.

12. The control arrangement of claim 2 wherein at least one of the circuit breaker operating units is, during use, arranged to switch the circuit breaker at voltage zero crossing.

13. The control arrangement of claim 3 wherein at least one of the circuit breaker operating units is, during use, arranged to switch the circuit breaker at voltage zero crossing.

14. The control arrangement of claim 2 wherein the central control system and the circuit breaker operating units are connected via a process fieldbus system.

15. The control arrangement of claim 3 wherein the central control system and the circuit breaker operating units are connected via a process fieldbus system.

16. The control arrangement of claim 4 wherein the central control system and the circuit breaker operating units are connected via a process fieldbus system.

17. The control arrangement of claim 2 wherein the circuit breaker operating units are each an IED or an I/O board.

18. The control arrangement of claim 3 wherein the circuit breaker operating units are each an IED or an I/O board.

19. The control arrangement of claim 4 wherein the circuit breaker operating units are each an IED or an I/O board.

20. The control arrangement of claim 5 wherein the circuit breaker operating units are each an IED or an I/O board.