Power compensator
A power compensator for compensating voltage at a location along a power transmission line, the compensator having a controller for controlling a voltage generated across the compensator, wherein the voltage is controlled to maintain a power transmission line voltage at a value dependent on the power transmission line location.
1. A power compensator for compensating voltage at a location along a power transmission line, the power compensator comprising:
a controller for controlling a voltage generated across the power compensator; and
a reactive power compensator and means for non-critical load shedding,
wherein the voltage is controlled to maintain a power transmission line voltage at a value dependent on a respective location along the power transmission line,
wherein the controller comprises a proportional-integral controller configured to receive an error signal, which is based on a difference between the voltage generated across the power compensator and a desired voltage, and output a modulation index used in determining an updated value of the desired voltage,
wherein the controller further comprises: a gain connected to the proportional-integral controller; and a subtractor connected to the gain and to the proportional-integral controller, and
wherein the controller is configured such that the modulation index output from the proportional-integral controller is fed to the gain to produce a gain modulation signal that is subtracted at the subtractor from a nominal voltage of the power transmission line to determine the updated value of the desired voltage.
2. The power compensator of claim 1 , wherein the controller is configured to provide control according to a gain value.
3. The power compensator of claim 2 , wherein the gain value is locally set.
4. The power compensator of claim 2 , wherein the gain value is remotely set.
5. A power compensation system, comprising: the power compensator as claimed in claim 1 ; and at least one load.
6. The power compensation system of claim 5 , wherein the load comprises an appliance.
7. The power compensation system of claim 5 , wherein the load comprises an overload load.
8. The power compensation system of claim 5 , further comprising a critical load in parallel with the compensator, wherein the compensator is configured to compensate to provide voltage across a critical load at a voltage value dependent on a respective location along the power transmission line.
9. A power transmission system, comprising: a power transmission line; and a plurality of power compensators, each as claimed in claim 1 , at respective locations along the power transmission line and each power compensator of the plurality of power compensators having a respective voltage value, wherein a power line transmission voltage is controlled by the plurality of power compensators.
10. The power transmission system of claim 9 , wherein the power transmission line comprises a distribution line.
11. The power compensator of claim 1 , wherein the voltage value is further dependent on a droop characteristic.
12. The power compensation system of claim 5 , wherein the at least one load comprises a smart load network connected to the power compensator.
13. A power compensation system, comprising: the power compensator as claimed in claim 1 ; and a smart load network connected to the power compensator.
14. A method of providing power compensation at a respective location along a power transmission line, the method comprising:
controlling a voltage generated across a power compensator at a respective location along the power transmission line to maintain a power transmission line voltage at a voltage value dependent on the respective location along the power transmission line; and
shedding a non-critical load,
wherein controlling the voltage generated across a power compensator comprises:
receiving, by a controller, the voltage generated across the power compensator;
generating an error signal based on a difference between the voltage generated across the power compensator and a desired voltage;
inputting the error signal into a proportional-integral controller of the controller; and
outputting, by the proportional-integral controller, a modulation index used in determining an updated value of the desired voltage;
feeding the modulation index output from the proportional-integral controller to a gain of the controller to produce a gain modulation signal; and
subtracting, at a subtractor of the controller, the gain modulation signal from a nominal voltage of the power transmission line to determine the updated value of the desired voltage.
15. The method of providing power compensation of claim 14 , wherein controlling the voltage value is further dependent on a droop characteristic.
16. The method of providing power compensation of claim 15 , the method further comprising: providing the power compensator; and connecting the power compensator to at least one load.
17. The method of providing power compensation of claim 16 , further comprising connecting the power compensator to at least one non-critical load.
18. The method of providing power compensation of claim 16 , wherein the at least one load comprises a smart load network.