Protection circuits
A protection circuit, for protecting a whole or part of a HVDC power transmission network, includes a number of sets of sensors, each of which set defines a respective protection zone. The protection circuit also includes a controller that is programmed to evaluate sensor information received from the sensors to determine whether a fault has occurred within a protection zone. The controller is further programmed, in the event of a sensor in a protection zone failing, to dynamically reconfigure the affected protection zone by including a sensor from another protection zone.
1. A protection circuit, for protecting a whole or part of a high voltage direct current (HVDC) power transmission network, comprising:
a plurality of sets of sensors, each of which set defines a respective protection zone, wherein a first protection zone of the protection circuit comprises a first sensor of the set of sensors, wherein a second protection zone of the protection circuit comprises a second sensor of the set of sensors; and
a controller comprising a first evaluation module programmed to evaluate first sensor information received from the first sensor to determine whether a fault has occurred within the first protection zone and further comprising a second evaluation module programmed to evaluate second sensor information received from the second sensor to determine whether a fault has occurred within the second protection zone,
the controller being further programmed, in the event of the first sensor failing, to dynamically reconfigure the first protection zone by adding the second sensor information from the second sensor to the first evaluation module's evaluation of the first protection zone.
2. A protection circuit according to claim 1 , wherein the controller includes a switching module to select the second sensor to be added to the first protection zone based on the dynamic reconfiguration.
3. A protection circuit according to claim 2 , wherein the switching module receives first and second forms of sensor information from each sensor, the first form of sensor information being current flow information and the second form of sensor information being sensor status information.
4. A protection circuit according to claim 3 , wherein the switching module utilises the sensor status information to identify a failed sensor and thereafter select the second sensor to reconfigure the first protection zone.
5. A protection circuit according to claim 4 , wherein following the identification of the first sensor failing, the switching module inhibits further transmission within the first evaluation module of the current flow information from the first sensor.
6. A protection circuit according to claim 3 , wherein at least one of the first evaluation module or the second evaluation module is a unitary evaluation module configured to evaluate whether the current flow information from a single sensor exceeds a predetermined threshold.
7. A protection circuit according to claim 3 , wherein at least one of the first evaluation module or the second evaluation module is a multiple evaluation module configured to evaluate whether a summation of the current flow information from a plurality of sensors exceeds a predetermined threshold.
8. A protection circuit according to claim 3 , wherein the transfer of current flow information from the switching module to each evaluation module is synchronised.
9. A method of operating a protection circuit for a whole or part of a HVDC power transmission network, the protection circuit including a plurality of sets of sensors each of which set defines a respective protection zone, wherein a first protection zone of the protection circuit comprises a first sensor of the set of sensors, wherein a second protection zone of the protection circuit comprises a second sensor of the set of sensors, and a controller comprising a first evaluation module which receives first sensor information from the first sensor, and further comprising a second evaluation module which receives second sensor information from the second sensor, and
the method comprising the steps of:
(a) evaluating, using the first evaluation module, the first sensor information to determine whether a fault has occurred within the first protection zone; and
(b) in the event of the first sensor in the first protection zone failing, dynamically reconfiguring the first protection zone by adding the second sensor information from the second sensor to the first evaluation module's evaluation of the first protection zone.