CN-122017442-A - Ground fault judging method and device for two-phase power transmission line

CN122017442ACN 122017442 ACN122017442 ACN 122017442ACN-122017442-A

Abstract

The application provides a method and a device for judging a ground fault of a two-phase power transmission line, and relates to the technical field of power systems. The distance protection method for the ground faults of the two-phase transmission line comprises the steps of determining a zero sequence compensation coefficient of the two-phase transmission line according to actual measured self-impedance and actual measured trans-impedance of the two-phase transmission line, determining sum flow of an operating phase according to actual measured two-phase current and a preset sum flow calculation mode of the operating phase in the two-phase transmission line under the condition that the two-phase transmission line is faulty, determining working voltage and polarization voltage of the operating phase according to the zero sequence compensation coefficient, the actual measured two-phase current and the sum flow and the actual measured three-phase voltage, the working voltage calculation mode and the polarization voltage calculation mode on a power supply side bus of the two-phase transmission line, and determining whether the two-phase transmission line is faulty due to the ground faults according to the ground fault judgment mode.

Inventors

YAN JUN
LU JINFENG
XU XIAOCHUN
ZHAO QINGCHUN
XIE HUA
WANG YULONG
LI BEN
NIU HUAMIN
HUANG TAO
ZHANG HONGXI

Assignees

南京南瑞继保电气有限公司
南京南瑞继保工程技术有限公司

Dates

Publication Date: 20260512
Application Date: 20241111

Claims (10)

1. The method for judging the ground fault of the two-phase power transmission line is characterized by comprising the following steps of: Determining a zero sequence compensation coefficient of the two-phase power transmission line according to the measured self impedance and the measured transimpedance of the two-phase power transmission line; under the condition that the two-phase power transmission line fails, determining the sum flow of the running phase according to the actual measured two-phase current of the running phase in the two-phase power transmission line and a preset sum flow calculation mode; Determining the working voltage and the polarization voltage of the operation phase according to the zero sequence compensation coefficient, the actually measured two-phase current, the sum current, the actually measured three-phase voltage on a power supply side bus of the two-phase transmission line, a preset working voltage calculation mode and a preset polarization voltage calculation mode; And according to a preset ground fault judging mode, combining the sum current, the working voltage and the polarization voltage to determine whether the fault of the two-phase power transmission line in a preset protection range is a ground fault or not.
2. The method of claim 1, wherein determining the zero sequence compensation coefficient of the two-phase transmission line based on the measured self-impedance and the measured transimpedance of the two-phase transmission line comprises: determining the positive sequence impedance and the zero sequence impedance of the two-phase power transmission line according to the actually measured self impedance and the actually measured transimpedance; And determining the zero sequence compensation coefficient according to the positive sequence impedance and the zero sequence impedance.
3. The method as recited in claim 1, further comprising: judging whether the two-phase power transmission line has faults or not according to the actually measured two-phase current of the running phase in the two-phase power transmission line and a preset fault judging condition.
4. A method according to claim 3, wherein the predetermined fault determination conditions include a first fault determination condition and a second fault determination condition; The judging whether the two-phase power transmission line has faults according to the actually measured two-phase current of the running phase in the two-phase power transmission line and the preset fault judging condition comprises the following steps: determining the variation of the measured current according to the measured two-phase current and a preset current variation calculation mode; determining whether the two-phase power transmission line meets the first fault judgment condition according to the variation and a preset first fault judgment mode; Determining whether the two-phase power transmission line meets the second preset fault condition according to the actually measured two-phase current and a preset second fault judging mode; Determining that the two-phase power transmission line fails under a first condition, wherein the first condition is a condition that the first failure judgment condition is met or/and the second failure judgment condition is met; And under the non-first condition, determining that the two-phase power transmission line does not fail.
5. The method according to claim 1, wherein the determining whether the fault of the two-phase transmission line in the preset protection range is a ground fault according to the preset ground fault determination method by combining the sum current, the working voltage and the polarization voltage includes: Determining a phase angle difference judging mode and a sum flow judging mode according to the ground fault judging mode; Determining whether the two-phase power transmission line meets a first ground fault judgment condition within the preset protection range according to the phase angle difference judgment mode, the working voltage and the polarization voltage; determining whether the two-phase power transmission line meets a second ground fault judgment condition within the preset protection range according to the sum flow judgment mode, a preset rated current amplitude and the sum flow; Under the condition that the first grounding fault judging condition and the second grounding fault judging condition are simultaneously met, determining that the fault of the two-phase power transmission line in the preset protection range is a grounding fault; And under the condition that the first ground fault judging condition and the first ground fault judging condition are not met at the same time, determining that the fault of the two-phase power transmission line in the preset protection range is not a ground fault.
6. The method of claim 5, wherein determining whether the two-phase transmission line satisfies a first ground fault determination condition within a preset protection range according to the phase angle difference determination manner, the operating voltage, and the polarization voltage comprises: Obtaining a phase angle difference threshold range according to the preset protection range; Determining whether a phase angle difference between the working voltage and the polarized voltage is within the phase angle difference threshold range based on the phase angle difference judgment mode; and under the condition that the phase angle difference is within the phase angle difference threshold range, determining that the two-phase power transmission line meets the first ground fault judging condition within the preset protection range.
7. The method according to claim 5, wherein determining whether the two-phase power transmission line satisfies a second ground fault determination condition within the preset protection range according to the sum current determination method, a preset rated current amplitude, and the sum current includes: Acquiring a sum current parameter and a rated current parameter based on the sum current judging mode; and determining whether the two-phase power transmission line meets a second ground fault judgment condition within the preset protection range according to the sum flow, the sum flow parameter, the rated current amplitude and the rated current parameter.
8. A distance protection device for a two-phase transmission line ground fault, comprising: the impedance determining module is used for determining a zero sequence compensation coefficient of the two-phase power transmission line according to the measured self impedance and the measured transimpedance of the two-phase power transmission line; The current determining module is used for determining the sum current of the running phase according to the actual measured two-phase current of the running phase in the two-phase power transmission line and a preset sum current calculation mode under the two-phase power transmission line; The voltage determining module is used for determining working voltage and polarization voltage according to the zero sequence compensation coefficient, the actually measured two-phase current, the sum current and the actually measured three-phase voltage on a power supply side bus of the two-phase power transmission line, a preset working voltage calculation mode and a preset polarization voltage calculation mode; And the fault judging module is used for determining whether the fault of the two-phase power transmission line in the preset protection range is a ground fault or not according to a preset ground fault judging mode by combining the sum current, the working voltage and the polarization voltage.
9. An electronic device, comprising: A processor; A memory storing a computer program which, when executed by the processor, causes the processor to perform the distance protection method of a two-phase transmission line ground fault as claimed in any one of claims 1 to 7.
10. A non-transitory computer readable storage medium having stored thereon computer readable instructions that, when executed by a processor, cause the processor to perform the distance protection method of a two-phase transmission line ground fault of any one of claims 1-7.

Description

Ground fault judging method and device for two-phase power transmission line Technical Field The application relates to the technical field of power systems, in particular to a method and a device for judging a ground fault of a two-phase power transmission line. Background A two-phase electric power transmission line, generally referred to as an electric power transmission line adopting a two-phase power supply mode, is used for providing electric power to an electrified railway (such as a high-speed rail, an electric iron, etc.). Along with the rapid development of high-speed railways, two-phase power supply lines are widely applied to railway systems. The two-phase power transmission line belongs to an asymmetric line, and the grounding distance protection principle based on a three-phase symmetric system cannot be directly applied to the two-phase electric iron power transmission line. In the related art, for a two-phase electric iron transmission line, a protection device for collecting only single-ended electric quantity is generally configured at a system side, and the sum current protection and the over current protection under the configuration can reflect the ground fault, but the risk of refusal exists, so that the current ground fault judging method is difficult to accurately judge the ground fault of the two-phase electric transmission line. Disclosure of Invention The application aims to provide a distance protection method and device for a two-phase power transmission line ground fault, electronic equipment and a storage medium. According to one aspect of the application, a distance protection method for a ground fault of a two-phase power transmission line is provided, and the distance protection method comprises the steps of determining a zero sequence compensation coefficient of the two-phase power transmission line according to actual measured self-impedance and actual measured trans-impedance of the two-phase power transmission line, determining the sum flow of an operating phase according to actual measured two-phase current and a preset sum flow calculation mode of the operating phase in the two-phase power transmission line under the condition that the two-phase power transmission line breaks down, determining the operating voltage and the polarization voltage of the operating phase according to the zero sequence compensation coefficient, the actual measured two-phase current and flow and the actual measured three-phase voltage on a power supply side bus of the two-phase power transmission line, the preset working voltage calculation mode and the preset polarization voltage calculation mode, and determining whether the fault of the two-phase power transmission line in a preset protection range is a ground fault or not according to the preset ground fault judgment mode. According to some embodiments, the zero sequence compensation coefficient of the two-phase power transmission line is determined according to the measured self-impedance and the measured transimpedance of the two-phase power transmission line, and the zero sequence compensation coefficient is determined according to the positive sequence impedance and the zero sequence impedance. According to some embodiments, the method further comprises judging whether the two-phase transmission line has faults according to the actually measured two-phase current of the running phase in the two-phase transmission line and a preset fault judging condition. According to some embodiments, the preset fault judging conditions comprise a first fault judging condition and a second fault judging condition, wherein judging whether the two-phase power transmission line has a fault or not according to actual measurement two-phase current of an operating phase in the two-phase power transmission line and the preset fault judging condition comprises determining the change amount of the actual measurement current according to an actual measurement two-phase current and a preset current change amount calculating mode, determining whether the two-phase power transmission line meets the first fault judging condition according to the change amount and a preset first fault judging mode, determining whether the two-phase power transmission line meets the first fault judging condition according to the calculated sum current and the preset second fault judging mode, and determining that the two-phase power transmission line has a fault under the first condition, wherein the first condition is that the first fault judging condition is met or/and the second fault judging condition is met, and determining that the two-phase power transmission line has no fault under the non-first condition. According to some embodiments, according to a preset ground fault judging mode, combining sum flow, working voltage and polarization voltage, determining whether a fault of a two-phase power transmission line in a preset protection range is a ground fault or not includes d