Direct current power delivery system and method

Patent metadata

Field	Value
Publication number	US-9438042-B2
Application number	US-201313769919-A
Country	US
Kind code	B2
Filing date	Feb 19, 2013
Priority date	Feb 19, 2013
Publication date	Sep 6, 2016
Grant date	Sep 6, 2016

Abstract

A power transmission system includes a first unit for carrying out the steps of receiving high voltage direct current (HVDC) power from an HVDC power line, generating an alternating current (AC) component indicative of a status of the first unit, and adding the AC component to the HVDC power line. Further, the power transmission system includes a second unit for carrying out the steps of generating a direct current (DC) voltage to transfer the HVDC power on the HVDC power line, wherein the HVDC power line is coupled between the first unit and the second unit, detecting a presence or an absence of the added AC component in the HVDC power line, and determining the status of the first unit based on the added AC component.

First claim

The invention claimed is:

1. A power transmission system comprising:
a first unit for carrying out the steps of:
receiving high voltage direct current (HVDC) power from an HVDC power line;
generating an alternating current (AC) component indicative of a status of the first unit;
adding the AC component to the HVDC power line;

a second unit for carrying out the steps of:
generating a direct current (DC) voltage to transfer the HVDC power on the HVDC power line, wherein the HVDC power line is coupled between the first unit and the second unit;
generate a compensatory AC component to eliminate the added AC component in the HVDC power line; and
determine the status of the first unit based on the generated compensatory AC component.

2. The power transmission system of claim 1 , wherein the status of the first unit comprises one or more anomalies at the first unit.

3. The power transmission system of claim 1 , wherein the status of the first unit comprises one or more load requirements at the first unit.

4. The power transmission system of claim 1 , wherein the first unit comprises a plurality of modules coupled to one or more power loads, and wherein each of the plurality of modules generates an unique alternating current (AC) component based on at least the status of the respective module of the first unit.

5. The power transmission system of claim 4 , wherein each of the modules in the first unit is configured to add the unique AC component to the HVDC power line in such a way that the added AC component is undetectable by at least one of other of the plurality of modules in the first unit.

6. The power transmission system of claim 1 , wherein the first unit comprises an energy storage unit configured to provide reactive power for generating the AC component.

7. The power transmission system of claim 1 , wherein the second unit is configured to identify at least one of a frequency, an amplitude, and a phase of the compensatory AC component to determine the status of the first unit.

8. The power transmission system of claim 1 , wherein the added AC component comprises a plurality of encoded cycles indicating the status of the first unit.

9. The power transmission system of claim 1 , wherein the second unit comprises a control unit for adjusting at least one of the DC voltage and a DC current in the HVDC power line based on the status of the first unit.

10. The power transmission system of claim 1 , wherein the first unit is coupled to at least one power load comprising oil and gas equipment.

11. A method comprising:
generating an alternating current (AC) component by a first unit, wherein the AC component indicates a status of the first unit;
adding, by the first unit, the AC component to a high voltage direct current (HVDC) power line coupled between the first unit and a second unit;
generating a compensatory AC component, by the second unit, to eliminate the added AC component in the HVDC power line; and
determining the status of the first unit, by the second unit, based on the compensatory AC component.

12. The method of claim 11 , wherein adding the AC component to the HVDC power line comprises adding the AC component to the HVDC power line in such a way that the AC component is undetectable by at least one of other modules and regulators in the first unit.

13. The method of claim 11 , wherein adding the AC component to the HVDC power line comprises adding the AC component to the HVDC power line in such a way that a direct current (DC) link current in the HVDC power line is maintained constant between the first unit and the second unit.

14. The method of claim 11 , wherein determining the status of the first unit comprises identifying at least one of a frequency, an amplitude, and a phase of the compensatory AC voltage to determine the status of the first unit.

15. The method of claim 11 , wherein determining the status of the first unit comprises decoding a plurality of encoded cycles comprised in the added AC component to determine the status of the first unit.

16. The method of claim 11 , wherein determining the status of the first unit further comprises adjusting a DC voltage or a DC current in the HVDC power line at the second unit based on the status of the first unit.

17. A power transmission system comprising:
a first unit for carrying out the steps of:
transmitting high voltage direct current (HVDC) power on an HVDC power line;
generating an alternating current (AC) component indicative of a status of the first unit;
adding the AC component to the HVDC power line;

a second unit for carrying out the steps of:
receiving the HVDC power from the HVDC power line, wherein the HVDC power line is coupled between the first unit and the second unit;
generating a compensatory AC component to eliminate the added AC component in the HVDC power line; and
determining the status of the first unit based on the generated compensatory AC component.

18. The power transmission system of claim 17 , wherein the first unit is coupled to a power generation unit comprising a wind turbine.

Assignees

• Gen Electric

Inventors

• Zhang Di
• Garces Luis Jose
• Dai Jian
• Lai Rixin

Classifications

• H02J3/381

  Dispersed generators · CPC title

• H02J2101/20

  Dispersed power generation using renewable energy sources · CPC title

• H02J13/12

  Monitoring network conditions, e.g. electrical magnitudes or operational status · CPC title

• H02J13/1323 Primary

  using optical fibres · CPC title

• Y04S10/123

  the energy generation units being or involving renewable energy sources · CPC title