Direct current transmission system and method
First Claim
1. An AC power transmission system converted for transmission of high voltage direct current (HVDC) power, the converted system comprising:
- an AC cable system comprising three cables with conductor dimensions and insulation dimensions configured for transmission of a rated peak line-to-ground AC voltage;
a first converter system structured to receive AC power, convert the AC power to DC power and output the DC power to the AC cable system, the first converter system being controllable to vary voltage of the DC power over a range extending from a rated HVDC voltage to a second DC voltage lower than the rated HVDC voltage, the rated HVDC voltage being equal to or greater than the rated peak line-to-ground voltage of the AC cable system;
a second power converter system structured to receive the DC power from the AC cable system, convert the DC power to a second AC power, and output the second AC power; and
a control system structured to receive power demand information, determine a reduced DC voltage less than the rated HVDC voltage using the power demand information, control the first converter system such that the voltage of the DC power is controlled to the reduced voltage effective to reduce stress on the AC cable system relative to the HVDC voltage, and control the second power converter system to operate in an active power control mode.
4 Assignments
0 Petitions
Accused Products
Abstract
Unique systems, methods, techniques and apparatuses of power transmission systems are disclosed herein. One exemplary embodiment is an AC power transmission system converted for transmission of high voltage direct current (HVDC) power, the converted system comprising an AC cable system, a first converter system, a second converter system, and a control system. The first converter system is structured to receive and convert AC power to DC power and output the DC power. The second power converter system is structured to receive the DC power, convert the DC power to a second AC power, and output the second AC power. The control system is structured to receive power demand information, determine a reduced DC voltage less than a rated HVDC voltage, control the first converter system such that the DC power is controlled to the reduced voltage, and control the second power converter system to operate in an active power control mode.
-
Citations
21 Claims
-
1. An AC power transmission system converted for transmission of high voltage direct current (HVDC) power, the converted system comprising:
-
an AC cable system comprising three cables with conductor dimensions and insulation dimensions configured for transmission of a rated peak line-to-ground AC voltage; a first converter system structured to receive AC power, convert the AC power to DC power and output the DC power to the AC cable system, the first converter system being controllable to vary voltage of the DC power over a range extending from a rated HVDC voltage to a second DC voltage lower than the rated HVDC voltage, the rated HVDC voltage being equal to or greater than the rated peak line-to-ground voltage of the AC cable system; a second power converter system structured to receive the DC power from the AC cable system, convert the DC power to a second AC power, and output the second AC power; and a control system structured to receive power demand information, determine a reduced DC voltage less than the rated HVDC voltage using the power demand information, control the first converter system such that the voltage of the DC power is controlled to the reduced voltage effective to reduce stress on the AC cable system relative to the HVDC voltage, and control the second power converter system to operate in an active power control mode. - View Dependent Claims (2, 3, 4, 5, 6, 7)
-
-
8. A method for converting an AC power transmission system to a high voltage direct current (HVDC) power transmission system, the method comprising:
-
coupling a first converter system to an AC cable system, the first converter system structured to receive AC power with an input, convert the AC power to DC power with a voltage controllable to a rated HVDC voltage and to one or more voltages lower than the rated HVDC voltage, and transmit the DC power with the AC cable system, the AC cable system including a plurality of transmission lines structured to transmit AC power with a rated peak-to-ground AC voltage, the rated HVDC voltage being greater than the rated AC voltage; coupling a second converter system to the AC cable system, the second converter system structured to receive the DC power from the first converter system, convert the DC power to a second AC power, and output the second AC power; operating a control system to periodically receive power demand information, calculate a DC voltage less than the rated HVDC using the power demand information, control the first converter system such that the voltage of the DC power transmitted with the first converter system is effective to reduce stress on the AC cabling system relative to the HVDC voltage, and control the second converter system using the power demand information. - View Dependent Claims (9, 10, 11, 12, 13, 14)
-
-
15. An HVDC power system structured to retrofit a portion of an AC transmission system including a plurality of AC transmission lines structured to transmit AC power with a rated AC voltage, the power system comprising:
-
an AC/DC converter system operatively coupled to the plurality of AC transmission lines and structured to receive AC power, convert the AC power to DC power with a voltage less than or equal to a rated HVDC voltage greater than the rated AC voltage, and output the DC power; a DC/AC converter system operatively coupled to the plurality of AC transmission lines and structured to receive the DC power from the AC/DC converter system, convert the DC power to a second AC power, and output the second AC power; a control system structured to receive power demand information, calculate a DC operating voltage within a range extending over at least 90% to 100% of the rated HVDC voltage effective to reduce stress on the AC transmission lines compared to a constant operating voltage of rated HVDC voltage, operate the AC/DC converter system so as to convert the received AC power to DC power at the calculated DC operating voltage, and to operate the DC/AC converter system so as to convert the DC power to AC power using the power demand information. - View Dependent Claims (16, 17, 18, 19, 20, 21)
-
Specification