Method and apparatus for detection of power system disturbance within a digital substation
View Patent ↗An objective of the application is to provide a method for detecting a disturbance in a power system within a digital substation and an apparatus using the same. The method includes: sensing electrical parameters at an end of a transmission line; sampling the sensed electrical parameters; extracting traveling-wave information from high frequency component of the samples using a signal processing method; and if the extracted traveling-wave information indicating occurrence of the disturbance, transmitting the extracted traveling-wave information to an intelligent electronic device of the digital substation from a merging unit or non-conventional instrument transformer of the digital substation. As compared with the amount of the sample data of the sensed electrical parameters, the amount of the data representing the extracted traveling-wave information is reduced. Thus the extracted traveling-wave information can be transmitted via a data link with a relatively narrow bandwidth, such as the process bus under standard IEC 61850.
1. A method for detecting a disturbance in a power system within a digital substation, including:
sensing electrical parameters at an end of a transmission line;
sampling the sensed electrical parameters using a sampling rate between 10 kHz to 10 MHz;
extracting travelling-wave information from a high frequency component of the samples using a signal processing method, wherein the travelling-wave information represents polarity, direction, amplitude, rate of change and/or timing of the travelling-wave; and
if the extracted travelling-wave information indicates occurrence of the disturbance, transmitting the extracted travelling-wave information to an intelligent electronic device of the digital substation from a merging unit or non-conventional instrument transformer of the digital substation, wherein the merging unit or non-conventional instrument transformer is structured to communicate with the intelligent electronic device according to IEC 61850 communication protocols.
2. The method according to claim 1 , wherein:
the electrical parameters are voltage, current at the end of the transmission line.
3. The method according to claim 2 , wherein:
the signal processing method is one of wavelet transformation or filter-based signal processing method.
4. The method according to claim 2 , further including:
if the extracted travelling-wave information indicates existence of the disturbance, transmitting it to a disturbance recorder of the digital substation from a merging unit or non-conventional instrument transformer of the digital substation.
5. The method according to claim 1 , wherein:
the signal processing method is one of wavelet transformation or filter-based signal processing method.
6. The method according to claim 1 , further including:
if the extracted travelling-wave information indicates existence of the disturbance, transmitting it to a disturbance recorder of the digital substation from a merging unit or non-conventional instrument transformer of the digital substation.
7. The method according to claim 1 , wherein:
the intelligent electronic device includes a protection relay and/or a fault locator.
8. A disturbance detection apparatus for a power system within a digital substation, including:
an electrical parameter sensor for sensing an electrical parameter at an end of a transmission line;
a sampling device, for sampling the sensed electrical parameter using a sampling rate between 10 kHz to 10 MHz;
a processor, for extracting travelling-wave information from high frequency component of the samples using a signal processing method and judging if it indicates occurrence of the disturbance, wherein the travelling-wave information represents polarity, direction, amplitude, rate of change and/or timing of the travelling-wave; and
a transmitter arranged in a merging unit of the digital substation or a non-conventional instrument transformer of the digital substation, for transmitting the extracted travelling-wave information to an intelligent electronic device of the digital substation from the merging unit or the non-conventional instrument transformer using IEC 61850 communication protocols if the extracted travelling-wave information indicates the occurrence of the disturbance.
9. The disturbance detection apparatus according to claim 8 , wherein:
the sampling device is arranged in the merging unit of the digital substation or the non-conventional instrument transformer of the digital substation.
10. The disturbance detection apparatus according to claim 9 , wherein:
the processor is arranged in the merging unit of the digital substation or the non-conventional instrument transformer of the digital substation.
11. The disturbance detection apparatus according to claim 9 , wherein:
the electrical parameter sensor is of a current transformer or as a part of the non-conventional instrument transformer.
12. The disturbance detection apparatus according to claim 8 , wherein:
the processor is arranged in the merging unit of the digital substation or the non-conventional instrument transformer of the digital substation.
13. The disturbance detection apparatus according to claim 8 , wherein:
the electrical parameter sensor is of a current transformer or as a part of the non-conventional instrument transformer.
14. The disturbance detection apparatus according to claim 8 , wherein:
the electrical parameter sensor is of a voltage transformer or as a part of the non-conventional instrument transformer.
15. The disturbance detection apparatus according to claim 14 , wherein:
the transmitter is further adapted for transmitting the extracted travelling-wave information to a disturbance recorder of the digital substation if it indicates existence of the disturbance.
16. The disturbance detection apparatus according claim 8 , wherein:
the transmitter is further adapted for transmitting the extracted travelling-wave information to a disturbance recorder of the digital substation if it indicates existence of the disturbance.
17. The disturbance detection apparatus according claim 8 , wherein:
the intelligent electronic device includes a protection relay and/or fault locator.
18. A digital substation, including:
the disturbance detection apparatus according to claim 8 ;
the merging unit or the non-conventional instrument transformer; and
the intelligent electronic device.