Distributed floating series active impendances for power transmission systems
First Claim
1. An active module for attachment to a power transmission line of a transmission system comprising:
- (a) a single phase main transformer primary formed to attach to a power transmission line without breaking the line such that the power line forms the secondary of the main transformer;
(b) an electrical energy storage device;
(c) a switching circuit formed of gate controlled switching devices connected to the electrical energy storage device to exchange power therewith and having output lines connected to the main transformer primary; and
(d) a controller connected to the switching devices in the switching circuit to control the switching of the switching devices for transfer of power between the main transformer primary and the electrical energy storage device to provide a selected impedance injected in the transmission line coupled through the main transformer primary, the module electrically isolated from ground and from other phase lines of the transmission system.
3 Assignments
0 Petitions
Accused Products
Abstract
Floating electrically isolated active impedance modules are formed to attach to power transmission lines without breaking the lines such that the power line forms a secondary of the main transformer of the module. Each module includes an electrical energy storage device and a switching circuit, such as a single phase inverter, connected to the storage device and to the main transformer primary winding. The inverter can be controlled to couple a selected voltage to the transmission line through the main transformer primary winding which can provide effective positive impedance, negative impedance, or a voltage at or near phase quadrature with the line current. Many active impedance modules may be distributed over a power system grid to allow control of the impedance of the power lines in the grid and to steer power through the grid, with each module electrically isolated from ground and from other phase lines of the transmission system.
94 Citations
32 Claims
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1. An active module for attachment to a power transmission line of a transmission system comprising:
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(a) a single phase main transformer primary formed to attach to a power transmission line without breaking the line such that the power line forms the secondary of the main transformer; (b) an electrical energy storage device; (c) a switching circuit formed of gate controlled switching devices connected to the electrical energy storage device to exchange power therewith and having output lines connected to the main transformer primary; and (d) a controller connected to the switching devices in the switching circuit to control the switching of the switching devices for transfer of power between the main transformer primary and the electrical energy storage device to provide a selected impedance injected in the transmission line coupled through the main transformer primary, the module electrically isolated from ground and from other phase lines of the transmission system. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. An active module for attachment to a power transmission line of a transmission system comprising:
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(a) a single phase main transformer primary formed to attach to a power transmission line without breaking the line such that the power line forms the secondary of the main transformer; (b) an electrical energy storage device; (c) a switching circuit formed of gate controlled switching devices connected to the electrical energy storage device to exchange power therewith and having output lines connected to the main transformer primary; and (d) a controller connected to the switching devices in the switching circuit to control the switching of the switching devices for transfer of power between the main transformer primary and the electrical energy storage device to provide a selected impedance injected in the transmission line coupled through the main transformer primary, the module electrically isolated from ground and from other phase lines of the transmission system; wherein the electrical energy storage device is an inductor, and wherein the switching circuit comprises a series switch connected in series between the main transformer primary and the inductor, and a parallel switch connected in parallel with the inductor, the controller connected to the series switch and the parallel switch to switch them alternately with a duty cycle d for the series switch and a duty cycle (1−
d) for the parallel switch. - View Dependent Claims (15)
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16. An active module for attachment to a power transmission line of a transmission system comprising:
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(a) a single phase main transformer primary formed to attach to a power transmission line without breaking the line such that the power line forms the secondary of the main transformer wherein the main transformer primary has a winding which comprises multiple turns of wire with sections of the wire extending in a longitudinal direction parallel to the transmission line when the transformer primary winding is mounted on the transmission line; (b) an electrical energy storage capacitor; (c) a single phase inverter connected by DC bus lines to the electrical storage capacitor to exchange power therewith and having output lines connected to the main transformer primary winding, wherein the inverter is formed of gate controlled switching devices connected in a bridge configuration, the inverter connected between the DC bus lines that are connected to the electrical storage capacitor; and (d) a controller connected to the inverter to control the switching of the inverter switching devices for transfer of power between the main transformer primary winding and the electrical storage capacitor to provide a selected impedance in the transmission line coupled through the main transformer primary winding, the module electrically isolated from ground and from other phase lines of the transmission system. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24, 25)
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26. A method of actively injecting a series voltage in a transmission line of a three-phase transmission system comprising:
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(a) coupling a transformer primary winding to one of the phase lines of a high voltage power transmission line without breaking the line so that the transmission line forms the secondary of a transformer that is isolated from the other phase lines and from ground; and (b) selectively applying alternating voltage to the primary winding of the transformer to inject voltage in the transmission line at the position of the transformer to effectively provide an impedance in the transmission line wherein the step of coupling a transformer primary winding to one of the phase lines comprises providing a primary transformer winding wound about a split core and engaging the split core over the transmission line to form a primary winding and core that surrounds the transmission line. - View Dependent Claims (27, 28, 29, 30, 31, 32)
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Specification