Apparatus and method for controlling flow of power in a transmission line including stable reversal of power flow
First Claim
1. Apparatus for controlling power flow in the transmission line carrying an alternating current, said apparatus comprising:
- means sensing a first voltage and a second voltage at two spaced apart points on said transmission line;
means determining the transmission line voltage as a difference between said first voltage and said second voltage;
means determining a reactive component of said transmission line voltage; and
means injecting a compensating voltage in series into said transmission line which is one of in phase and 180°
out of phase with said reactive component of said transmission line voltage, and including means setting a magnitude of said compensating voltage to effect a predetermined change in power flow through said transmission line.
6 Assignments
0 Petitions
Accused Products
Abstract
Power flow in a transmission line carrying alternating current is controlled by injecting into the transmission line in series a compensating voltage which is either in phase or 180° out of phase with a reactive component of the transmission line voltage. The compensating voltage is generated by a voltage source converter operated by a controller which determines the angle of the transmission line voltage from voltage measurements taken at spaced apart points on the transmission line. Operation of the inverter in this voltage control mode results in an increase in power flow when the compensating voltage is injected at 180° out of phase with the voltage across the transmission line effective reactance. When the compensating voltage is injected in phase with the voltage across the transmission line effective reactance, the power flow decreases at first from the uncompensated value and can be reduced to zero when the compensating voltage equals the voltage across the transmission line effective reactance without compensation. Further increase in the compensating voltage in the same direction reverses the direction of power flow.
39 Citations
8 Claims
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1. Apparatus for controlling power flow in the transmission line carrying an alternating current, said apparatus comprising:
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means sensing a first voltage and a second voltage at two spaced apart points on said transmission line; means determining the transmission line voltage as a difference between said first voltage and said second voltage; means determining a reactive component of said transmission line voltage; and means injecting a compensating voltage in series into said transmission line which is one of in phase and 180°
out of phase with said reactive component of said transmission line voltage, and including means setting a magnitude of said compensating voltage to effect a predetermined change in power flow through said transmission line. - View Dependent Claims (2, 3, 4)
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5. Apparatus for controlling power flow in a transmission line carrying an alternating current, said apparatus comprising:
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an inverter generating a compensating voltage; means injecting said compensating voltage in series into said transmission line; measuring means measuring transmission line parameters including a first voltage and a second voltage at spaced apart points on said transmission line; and control means comprising means determining from said transmission line parameters including said first voltage and said second voltage an effective voltage across effective transmission line reactance between said two points and means generating a control signal for operating said inverter to generate said compensating voltage in phase with or alternatively 180°
out of phase with said effective voltage. - View Dependent Claims (6)
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7. A method for controlling power flow in a transmission line carrying an alternating current, said method comprising the steps of:
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measuring voltage at two spaced apart points on said transmission line; determining a transmission line voltage as the difference between said voltages measured at said two spaced apart points; determining a reactive component of said transmission line voltage; generating a compensating voltage at a selected magnitude and one of in phase and 180°
out of phase with said reactive component; andinjecting said compensating voltage into said transmission line in series. - View Dependent Claims (8)
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Specification