Device and a method for voltage control in an electric transmission network
First Claim
1. A device for control of a compensator, connected to a polyphase electric transmission network, for reactive electric power in dependence on a voltage sensed in the transmission network, the device having a voltage controller which, in dependence on the difference of a reference value for said voltage and its sensed value, forms a reference value for a reactive power flow through the compensator, wherein the device comprises transformation means, which represent the sensed voltage as a voltage vector in a rotating two-phase system of coordinates and forms a compensation signal in dependence on a sensed change of the angular position of the voltage vector in the two-phase system of coordinates, and further comprises summation means for forming the reference value for reactive power flow through the compensator in dependence on the compensation signal.
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Abstract
A device for control of a compensator connected to a polyphase electric transmission network for reactive electric power in dependence on a voltage sensed in the transmission network. A voltage controller, in dependence on the difference of a reference value for the voltage and its sensed value, forms a reference value for a reactive power flow through the compensator. A transformation element represents the sensed voltage as a voltage vector in a rotating two-phase system of coordinates and forms a compensation signal in dependence on a sensed change of the angular position of the voltage vector in the two-phase system of coordinates. A summation element forms the reference value for reactive power flow through the compensator in dependence on the compensation signal.
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Citations
10 Claims
- 1. A device for control of a compensator, connected to a polyphase electric transmission network, for reactive electric power in dependence on a voltage sensed in the transmission network, the device having a voltage controller which, in dependence on the difference of a reference value for said voltage and its sensed value, forms a reference value for a reactive power flow through the compensator, wherein the device comprises transformation means, which represent the sensed voltage as a voltage vector in a rotating two-phase system of coordinates and forms a compensation signal in dependence on a sensed change of the angular position of the voltage vector in the two-phase system of coordinates, and further comprises summation means for forming the reference value for reactive power flow through the compensator in dependence on the compensation signal.
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6. A method for control of a compensator, connected to a polyphase electric transmission network, for reactive electric power in dependence on a voltage sensed in the transmission network, whereby a voltage controller is supplied with a reference value for said voltage and, in dependence on the difference of the reference value and the sensed value of the voltage, forms a reference value for a reactive power flow through the compensator, wherein
a voltage vector is formed which represents the sensed voltage in a rotating two-phase system of coordinates, a compensation signal is formed in dependence on a sensed change of the angular position of the voltage vector in the two-phase system of coordinates, and the reference value for reactive power flow through the compensator is formed in dependence on the compensation signal.
Specification