	US 11,852,669 B2
	Online analysis system and method for line loss of transmission line
Sike Wang, Hubei (CN); Jinlin Su, Hubei (CN); Lu Chen, Hubei (CN); Dengping Tang, Hubei (CN); Dongyue Ming, Hubei (CN); Peng Yao, Hubei (CN); Yu Guo, Hubei (CN); Lieqi Yan, Hubei (CN); Ming Lei, Hubei (CN); Xin Zheng, Hubei (CN); Shangpeng Wang, Hubei (CN); Linghua Li, Hubei (CN); Bo Pang, Hubei (CN); Tian Xia, Hubei (CN); Jun Li, Hubei (CN); Xin Wang, Hubei (CN); Qi Wang, Hubei (CN); Jun Li, Hubei (CN); Fan Li, Hubei (CN); Hong Shi, Hubei (CN); Zheng Guo, Hubei (CN); Xianjin Rong, Hubei (CN); Li Liu, Hubei (CN); Li Ding, Hubei (CN); Qin Guo, Hubei (CN); and Fuxiang Lv, Hubei (CN)
Assigned to State Grid Hubei Marketing Service Center (Measurement Center), Wuhan (CN)
Appl. No. 17/434,006
Filed by State Grid Hubei Marketing Service Center (Measurement Center), Hubei (CN)
PCT Filed May 12, 2021, PCT No. PCT/CN2021/093214 § 371(c)(1), (2) Date Aug. 26, 2021, PCT Pub. No. WO2021/238652, PCT Pub. Date Dec. 2, 2021.
Claims priority of application No. 202010445534.0 (CN), filed on May 24, 2020.
Prior Publication US 2022/0349931 A1, Nov. 3, 2022
Int. Cl. G01R 31/08 (2020.01); G01R 22/06 (2006.01); G01R 19/02 (2006.01)

CPC G01R 31/086 (2013.01) [G01R 19/02 (2013.01); G01R 22/063 (2013.01)]

5 Claims

1. An online analysis system for a line loss of a transmission line, comprising: at least one terminal extension, wherein the terminal extension is installed on a secondary terminal box side of a potential transformer (PT) and/or a current transformer (CT) in a transformer substation, and connected to a secondary-side output signal of the PT and/or the CT, each terminal extension comprises a collection module for collecting the secondary-side output signals of the PT and the CT, an electric energy metering module for electric energy metering, a clock synchronization module for time synchronization, a communications module for establishing a communication connection to another terminal, a storage module for local mass storage, and a human-computer interaction interface for real-time displaying and remote control, the terminal extension is configured to measure information of the secondary terminal box side of the PT and/or the CT, and measurement data of the terminal extension comprises time information and measurement information;

at least one terminal host, installed on a watt-hour meter side in a main control room, wherein the terminal host comprises a collection module for collecting the secondary-side output signals of the PT and the CT, an electric energy metering module for electric energy metering, a clock synchronization module for time synchronization, a communications module for establishing a communication connection to another terminal, a storage module for local mass storage, and a human-computer interaction interface for real-time displaying and remote control, the terminal host is configured to measure information of the watt-hour meter side in the main control room, and measurement data of the terminal host comprises time information and measurement information; wherein

time information synchronization between the terminal extension and the terminal host and between terminal extensions is performed by the clock synchronization module, and

communication between the terminal extension and the terminal host and between the terminal extensions is performed by the communications module; and

a line loss management platform, configured to receive the measurement data of the terminal extension and the terminal host, match the time information in the measurement data, and if the time information in the measurement data of the terminal extension and the terminal host is matched, and time information in measurement data of the terminal extensions is matched, determine corresponding line loss information based on corresponding measurement information;

wherein the line loss information obtained by the line loss management platform through data calculation comprises a loss of a transmission line between transformer substations at which two terminal extensions are located, and errors of PTs and/or CTs connected to the terminal extensions, or a loss of a secondary voltage drop of a PT;

wherein a method for calculating the loss of the secondary voltage drop of the PT is as follows:

loss information of the secondary voltage drop of the PT comprises a plurality of types of electric parameter error values, wherein the loss information of the secondary voltage drop comprises a voltage drop error of a secondary circuit, and a process for calculating the voltage drop error of the secondary circuit comprises:

calculating, according to the following formula, the voltage drop error monitored online for the secondary circuit of the PT:

wherein f represents a voltage ratio difference, and δ represents a voltage angle difference; and

the loss information of the secondary voltage drop further comprises an electric energy metering error caused by the secondary voltage drop, and a process for calculating the electric energy metering error comprises:

calculating, according to the following formula, the electric energy metering error caused by the secondary voltage drop of the PT:

wherein ε_rrepresents the electric energy metering error caused by the secondary voltage drop, f represents a voltage ratio difference, δ represents a voltage angle difference, and φ represents a load impedance angle of a high-voltage three-phase line;

wherein when two terminal extensions are networked, the line loss information comprises a loss of a transmission line between transformer substations at which the two terminal extensions are located, and errors of PTs and/or CTs connected to the terminal extensions; when the terminal extension and the terminal host are on a same metering line, and the terminal extension and the terminal host are networked, the line loss information comprises a loss of a secondary voltage drop of a PT; when the terminal extension and the terminal host are not on a same metering line, and the terminal extension and the terminal host are networked, the line loss information comprises a loss of a transmission line between transformer substations at which two extensions are located, errors of two transformers connected on the line, and a loss of a secondary voltage drop of a PT on a terminal host side; and

the line loss management platform is further configured to compare the line loss information when the terminal extension and the terminal host are not on a same metering line and the terminal extension and the terminal host are networked with a sum of the line loss information when two terminal extensions are networked and the line loss information when the terminal extension and the terminal host are on a same metering line and the terminal extension and the terminal host are networked, based on a same time.