Monitoring system for detecting error of harmonic filter in high voltage direct current (HVDC) system, and monitoring method thereof

Patent metadata

Field	Value
Publication number	US-10345361-B2
Application number	US-201615213725-A
Country	US
Kind code	B2
Filing date	Jul 19, 2016
Priority date	Jul 30, 2015
Publication date	Jul 9, 2019
Grant date	Jul 9, 2019

Abstract

Disclosed embodiments relate to a monitoring system for detecting an error of a harmonic filter in a high voltage direct current (HVDC) transmission system is disclosed. In some embodiments, the monitoring system comprises a harmonic filter including one or more capacitor units, a monitoring sensor unit sensing a voltage of at least one of the one or more capacitor units, and, a control unit monitoring a voltage error of the at least one capacitor unit using the sensing result.

First claim

What is claimed is:

1. A monitoring system for detecting an error of a harmonic filter in a high voltage direct current (HVDC) transmission system, wherein the HVDC transmission system converts AC power into DC power and converts the DC power into the AC power, wherein the harmonic filter removes a harmonic wave that is generated at the HVDC transmission system, the monitoring system comprising:
a harmonic filter comprising at least one capacitor, at least one inductor, and at least one resistor, and removing a harmonic wave through a combination of the at least one capacitor, the at least one inductor, and the at least one resistor, wherein the at least one capacitor includes a first capacitor, wherein the first capacitor comprises a plurality of capacitor units;
a monitoring sensor unit configured to sense a plurality of voltages corresponding to the plurality of capacitor units, respectively; and
a control unit configured to determine a voltage error of the plurality of capacitor units based on a sensing result.

2. The monitoring system according to claim 1 , wherein the plurality of capacitor units comprise a first capacitor unit and charging voltages of the plurality of capacitor units are equally set, and
wherein the control unit is further configured to determine a voltage error of the first capacitor unit if a voltage of the first capacitor unit is different from voltages of other capacitor units other than the first capacitor unit among the plurality of capacitor units.

3. The monitoring system according to claim 1 , wherein the plurality of capacitor units comprise a first capacitor unit, and
wherein the control unit is further configured to determine a voltage error of the first capacitor unit by comparing a reference voltage value of the first capacitor unit with a current voltage value of the first capacitor unit.

4. The monitoring system according to claim 1 , further comprising a gas insulated switchgear (GIS) configured to block a current from flowing into the harmonic filter,
wherein the control unit is further configured to switch the GIS to block the current from flowing into the harmonic filter when the voltage error of the at least one of the plurality of capacitor units is detected.

5. The monitoring system according to claim 1 , further comprising a capacitor bank,
wherein the capacitor bank comprises a combination of the plurality of capacitor units.

6. The monitoring system according to claim 1 , wherein the plurality of capacitor units are divided into a plurality of groups,
wherein the monitoring sensor unit is further configured to sense voltages of each of the plurality of groups.

7. The monitoring system according to claim 1 , further comprising a storage unit that stores data,
wherein the control unit is further configured to store a result of the determination of the voltage error of the plurality of capacitor units in the storage unit.

8. The monitoring system according to claim 7 , wherein the result of the determination of the voltage error of the plurality of capacitor units is a voltage value of each of the plurality of capacitor units, and a time at which the voltage value of each of the plurality of capacitor units is measured.

9. A monitoring method of a monitoring system for detecting an error of a harmonic filter in a high voltage direct current (HVDC) transmission system, wherein the HVDC transmission system converts AC power into DC power and converts the DC power into the AC power, wherein the harmonic filter removes a harmonic wave that is generated at the HVDC transmission system, the monitoring method comprising:
sensing a plurality of voltages corresponding to a plurality of capacitor units, respectively, in a harmonic filter, wherein the harmonic filter comprises a first capacitor, wherein the first capacitor comprises a combination of at least one of the plurality of capacitor units; and
determining a voltage error of the plurality of capacitor units based on the sensed voltage,
wherein the harmonic filter comprises at least one capacitor, at least one inductor, and at least one resistor, and removes a harmonic wave through a combination of the at least one capacitor, the at least one inductor, and the at least one resistor, and
wherein the at least one capacitor includes the first capacitor.

10. The monitoring method according to claim 9 , wherein the plurality of capacitor units comprise a first capacitor unit and charging voltages of the plurality of capacitor units are equally set, and
wherein the determining the voltage error of the plurality of capacitor units comprises determining a voltage error of a first capacitor unit if a voltage of the first capacitor unit is different from voltages of other capacitor units other than the first capacitor unit among the plurality of capacitor units.

11. The monitoring method according to claim 9 , wherein the plurality of capacitor units comprise a first capacitor unit, and
wherein the determining the voltage error of the plurality of capacitor units comprises determining a voltage error of the first capacitor unit by comparing a reference voltage value of the first capacitor unit with a current voltage value of the first capacitor unit.

12. The monitoring method according to claim 9 , further comprising switching a gas insulated switchgear (GIS) to block a current from flowing into the harmonic filter when the voltage error of the at least one of the plurality of capacitor units is detected.

13. The monitoring method according to claim 9 , wherein the monitoring system for detecting the error of the harmonic filter comprises a capacitor bank,
wherein the capacitor bank comprises a combination of the plurality of capacitor units.

14. The monitoring method according to claim 9 , wherein the plurality of capacitor units are divided into a plurality of groups,
and wherein sensing the voltage of the at least one of the one or more capacitor units comprises sensing voltages of each of the plurality of groups.

15. The monitoring method according to claim 9 , further comprising storing a result of determining the voltage error of the plurality of capacitor units.

Assignees

• Lsis Co Ltd

Inventors

• Choi Yong Kil

Classifications

• H02J3/00125

  Transmission line or load transient problems, e.g. overvoltage, resonance or self-excitation of inductive loads (H02J3/01 takes precedence) · CPC title

• G01R31/64 Primary

  Testing of capacitors · CPC title

• Y02E40/40

  Arrangements for reducing harmonics · CPC title

• Y02E60/60

  Arrangements for transfer of electric power between AC networks or generators via a high voltage DC link [HVCD] · CPC title

• H02J2003/365

  Reducing harmonics or oscillations in HVDC · CPC title