CN109188181B - Virtual connection judgment method for neutral line of secondary circuit of power grid voltage transformer - Google Patents
Virtual connection judgment method for neutral line of secondary circuit of power grid voltage transformer Download PDFInfo
- Publication number
- CN109188181B CN109188181B CN201811046800.1A CN201811046800A CN109188181B CN 109188181 B CN109188181 B CN 109188181B CN 201811046800 A CN201811046800 A CN 201811046800A CN 109188181 B CN109188181 B CN 109188181B
- Authority
- CN
- China
- Prior art keywords
- power grid
- measuring device
- harmonic voltage
- voltage transformer
- virtual connection
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
- G01R31/66—Testing of connections, e.g. of plugs or non-disconnectable joints
- G01R31/67—Testing the correctness of wire connections in electric apparatus or circuits
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Testing Of Short-Circuits, Discontinuities, Leakage, Or Incorrect Line Connections (AREA)
- Measurement Of Current Or Voltage (AREA)
Abstract
The invention discloses a method for judging virtual connection of a neutral line of a secondary circuit of a power grid voltage transformer, which solves the problem of accurately judging the virtual connection of two neutral points. Connecting the input side of a secondary measuring device of a star solution method with the output end of a star winding at the secondary side of a power grid voltage transformer, and connecting a neutral point at the input side of the secondary measuring device with a neutral point at the secondary side of the power grid voltage transformer through a neutral line; according to the measuring accuracy of the secondary measuring deviceTAnd calculating a measurement error in a measuring range, respectively and simultaneously measuring three-phase instantaneous voltages of a secondary side of the secondary measurement device, multiplying a zero sequence third harmonic voltage effective value by a transformation ratio of an input transformer of the secondary measurement device, and subtracting the measurement error to obtain a value which is a true value of the third harmonic voltage of the primary side of the secondary measurement device, so as to judge whether a virtual connection phenomenon occurs to a neutral line of a secondary circuit of the power grid voltage transformer. The method improves the rapidity and the accuracy of the judgment of the virtual connection of the neutral line of the secondary voltage loop.
Description
Technical Field
The invention relates to a method for judging virtual connection of a secondary voltage loop neutral line of a voltage transformer in a power grid, and belongs to the field of power system protection.
Background
The grid voltage transformer is an instrument for converting line voltage, and for a winding with a star-connected secondary side of the grid voltage transformer, a primary side of an input transformer of a secondary measuring device is required to be in star connection, a neutral point of the secondary side of the grid voltage transformer and a neutral point of the primary side of the input transformer of the secondary measuring device are required to be connected together, and one point is grounded. In the field measurement process, sometimes the virtual connection phenomenon occurs on the two neutral point connecting lines, which easily causes the malfunction or failure of the protection device. The method adopted when judging the virtual connection of two neutral points in the prior art is to judge whether zero sequence third harmonic voltage of a secondary side of a secondary measuring device input transformer exists or not, when the neutral line of the secondary side of a power grid voltage transformer is in virtual connection, third harmonic current in exciting current of the secondary measuring device input transformer cannot flow, and the existence of third harmonic voltage is detected on the secondary side of the secondary measuring device input transformer. The accuracy of the judgment method is not high, because the power grid has a certain degree of third harmonic voltage, when the two neutral point connecting lines are not in virtual connection, a certain amount of third harmonic voltage can be measured, and how to accurately judge the virtual connection of the two neutral points becomes a problem to be solved urgently on site.
Disclosure of Invention
The invention provides a method for judging the virtual connection of a neutral line of a secondary circuit of a power grid voltage transformer, which solves the technical problem of accurately judging the virtual connection of two neutral points.
The invention solves the technical problems by the following technical scheme:
the general concept of the invention is: connecting the input side of a star-connected secondary measuring device with the output end of a secondary side star winding of a power grid voltage transformer, connecting a neutral point of the input side of the secondary measuring device with a neutral point of the secondary side of the power grid voltage transformer through a neutral line, acquiring an allowable third harmonic voltage distortion rate L corresponding to the voltage grade of a power grid connected with the power grid voltage transformer according to the standard of GBT 14549 + 1993 power quality public power grid harmonic wave, and calculating an allowable value E of the third harmonic voltage according to the distortion rate2According to the measuring precision T and the measuring range of the secondary measuring device
Calculating the measurement error E1And measuring to obtain the zero sequence third harmonic voltage effective value of the secondary side of the secondary measuring device
The effective value of the zero sequence third harmonic voltage
Multiplying the transformation ratio k of the input transformer of the secondary measuring device, and subtracting the measurement error E1The obtained value is the true value of the third harmonic voltage at the primary side of the secondary measuring device, if the true value of the third harmonic voltage at the primary side of the secondary measuring device is larger than the allowable value E of the third harmonic voltage2If the true value of the third harmonic voltage on the primary side of the secondary measurement device is less than or equal to the allowable value E of the third harmonic voltage2And judging that the virtual connection phenomenon does not occur in the neutral line of the secondary circuit of the power grid voltage transformer.
The virtual connection judgment method for the neutral line of the secondary circuit of the power grid voltage transformer comprises the following steps:
firstly, connecting the input side of a star-connected secondary measuring device with the output end of a secondary side star winding of a power grid voltage transformerConnecting a neutral point at the input side of the secondary measuring device with a neutral point at the secondary side of a power grid voltage transformer through a neutral line, acquiring an allowed third harmonic voltage distortion rate L corresponding to the voltage level of a power grid connected with the power grid voltage transformer according to the standard of GBT 14549 + 1993 power quality public power grid harmonic, and calculating E according to the following formula2：
Wherein the content of the first and second substances,
is the primary side range of the secondary measuring device;
secondly, according to the measuring precision T and the measuring range of the secondary measuring device
Calculating the measurement error E1：
Wherein T is the measurement precision of the secondary measurement device;
thirdly, three-phase instantaneous voltages of the secondary side of the secondary measuring device are measured respectively and simultaneously, and third harmonic voltage of the secondary side is calculated according to a Fourier algorithm
The zero sequence third harmonic voltage is calculated according to the following formula
The fourth step: the effective value of the zero sequence third harmonic voltage
Multiplying the transformation ratio k of the input transformer of the secondary measuring device, and subtracting the measurement error E1The obtained value is the true value of the third harmonic voltage at the primary side of the secondary measuring device, if the true value of the third harmonic voltage at the primary side of the secondary measuring device is larger than the allowable value E of the third harmonic voltage2If the true value of the third harmonic voltage on the primary side of the secondary measurement device is less than or equal to the allowable value E of the third harmonic voltage2And judging that the virtual connection phenomenon does not occur in the neutral line of the secondary circuit of the power grid voltage transformer.
The invention provides the operable criterion of the virtual connection of the neutral line of the secondary circuit of the power grid voltage transformer, and improves the rapidity and the accuracy of the virtual connection judgment of the neutral line of the secondary voltage circuit.
Drawings
FIG. 1 is a diagram of a measurement circuit according to the present invention.
Detailed Description
The invention is further described below with reference to the accompanying drawings.
The virtual connection judgment method for the neutral line of the secondary circuit of the power grid voltage transformer comprises the following steps:
firstly, connecting the input side of a star-connected secondary measuring device with the output end of a star winding on the secondary side of a power grid voltage transformer, connecting a neutral point on the input side of the secondary measuring device with a neutral point on the secondary side of the power grid voltage transformer through a neutral line, obtaining an allowed third harmonic voltage distortion rate L corresponding to the voltage grade of a power grid connected with the power grid voltage transformer according to the standard of GBT 14549 + 1993 power quality public power grid harmonic wave, and calculating E according to the following formula2：
Wherein the content of the first and second substances,
is the primary side range of the secondary measuring device;
secondly, calculating a measurement error E according to the measurement precision and the measuring range of the secondary measurement device1
Wherein T is the measurement precision of the secondary measurement device, and has a larger relation with the input voltage transformer and the analog-digital sampling precision of the secondary measurement device;
thirdly, three-phase instantaneous voltages of the secondary side of the secondary measuring device are measured respectively and simultaneously, and third harmonic voltage of the secondary side is calculated according to a Fourier algorithm
The zero sequence third harmonic voltage is calculated according to the following formula
The fourth step: the effective value of the zero sequence third harmonic voltage
Multiplying the transformation ratio k of the input transformer of the secondary measuring device, and subtracting the measurement error E1The obtained value is the true value of the third harmonic voltage at the primary side of the secondary measuring device, if the true value of the third harmonic voltage at the primary side of the secondary measuring device is larger than the allowable value E of the third harmonic voltage2If the true value of the third harmonic voltage on the primary side of the secondary measurement device is less than or equal to the allowable value E of the third harmonic voltage2And judging that the virtual connection phenomenon does not occur in the neutral line of the secondary circuit of the power grid voltage transformer.
Claims (1)
1. A virtual connection judgment method for a neutral line of a secondary circuit of a power grid voltage transformer comprises the following steps:
firstly, connecting the input side of a star-connected secondary measuring device with the output end of a star winding on the secondary side of a power grid voltage transformer, connecting a neutral point on the input side of the secondary measuring device with a neutral point on the secondary side of the power grid voltage transformer through a neutral line, obtaining an allowed third harmonic voltage distortion rate L corresponding to the voltage grade of a power grid connected with the power grid voltage transformer according to the standard of GBT 14549 + 1993 power quality public power grid harmonic wave, and calculating E according to the following formula2：
Wherein the content of the first and second substances,
is the primary side range of the secondary measuring device;
secondly, according to the measuring precision T and the measuring range of the secondary measuring device
Calculating the measurement error E1：
Wherein T is the measurement precision of the secondary measurement device;
thirdly, three-phase instantaneous voltages of the secondary side of the secondary measuring device are measured respectively and simultaneously, and third harmonic voltage of the secondary side is calculated according to a Fourier algorithm
The zero sequence third harmonic voltage is calculated according to the following formula
The fourth step: the effective value of the zero sequence third harmonic voltage
Multiplying the transformation ratio k of the input transformer of the secondary measuring device, and subtracting the measurement error E1The obtained value is the true value of the third harmonic voltage at the primary side of the secondary measuring device, if the true value of the third harmonic voltage at the primary side of the secondary measuring device is larger than the allowable value E of the third harmonic voltage2If the true value of the third harmonic voltage on the primary side of the secondary measurement device is less than or equal to the allowable value E of the third harmonic voltage2And judging that the virtual connection phenomenon does not occur in the neutral line of the secondary circuit of the power grid voltage transformer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811046800.1A CN109188181B (en) | 2018-09-08 | 2018-09-08 | Virtual connection judgment method for neutral line of secondary circuit of power grid voltage transformer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811046800.1A CN109188181B (en) | 2018-09-08 | 2018-09-08 | Virtual connection judgment method for neutral line of secondary circuit of power grid voltage transformer |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN109188181A CN109188181A (en) | 2019-01-11 |
| CN109188181B true CN109188181B (en) | 2020-09-04 |
Family
ID=64915516
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201811046800.1A Active CN109188181B (en) | 2018-09-08 | 2018-09-08 | Virtual connection judgment method for neutral line of secondary circuit of power grid voltage transformer |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN109188181B (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115267621B (en) * | 2022-06-24 | 2023-03-24 | 北京天能继保电力科技有限公司 | Virtual connection judgment method and device for secondary circuit wiring terminal of power grid current transformer |
| CN115166603B (en) * | 2022-06-24 | 2023-02-28 | 北京天能继保电力科技有限公司 | Virtual connection judgment method and device for secondary circuit wiring terminal of power grid voltage transformer |
| CN115754881B (en) * | 2023-01-04 | 2023-04-25 | 武汉格蓝若智能技术股份有限公司 | Virtual connection judging method and device for secondary side loop of voltage transformer |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101788633A (en) * | 2010-03-10 | 2010-07-28 | 南京南瑞继保电气有限公司 | Method for judging breakage of voltage transformer circuit |
| CN102243283A (en) * | 2011-04-02 | 2011-11-16 | 宁波电业局 | Neutral line breakage detection method of voltage secondary loop and apparatus thereof |
| KR101449706B1 (en) * | 2014-01-24 | 2014-10-15 | 이영돈 | Distributing board for realtime segmented sensing fault, harmonic wave and grounding resistance of power line and having a brocking and recovering function |
| CN106124920A (en) * | 2016-06-28 | 2016-11-16 | 国网河南桐柏县供电公司 | Transformator neutral conductor virtual connection fault detection method |
| CN206114821U (en) * | 2016-10-31 | 2017-04-19 | 中冶华天南京电气工程技术有限公司 | Verifying attachment of voltage transformer opening triangle protection |
| CN106646092A (en) * | 2016-12-13 | 2017-05-10 | 中国二冶集团有限公司 | Detection method for secondary system of voltage transformer |
| CN207662990U (en) * | 2017-12-08 | 2018-07-27 | 包头钢铁（集团）有限责任公司 | A kind of detecting system of CT secondary circuits open circuit and virtual connection |
| CN208013377U (en) * | 2018-03-13 | 2018-10-26 | 浙江海洋大学 | Low-voltage circuit breaker voltage monitoring and voltage protection |
-
2018
- 2018-09-08 CN CN201811046800.1A patent/CN109188181B/en active Active
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101788633A (en) * | 2010-03-10 | 2010-07-28 | 南京南瑞继保电气有限公司 | Method for judging breakage of voltage transformer circuit |
| CN102243283A (en) * | 2011-04-02 | 2011-11-16 | 宁波电业局 | Neutral line breakage detection method of voltage secondary loop and apparatus thereof |
| KR101449706B1 (en) * | 2014-01-24 | 2014-10-15 | 이영돈 | Distributing board for realtime segmented sensing fault, harmonic wave and grounding resistance of power line and having a brocking and recovering function |
| CN106124920A (en) * | 2016-06-28 | 2016-11-16 | 国网河南桐柏县供电公司 | Transformator neutral conductor virtual connection fault detection method |
| CN206114821U (en) * | 2016-10-31 | 2017-04-19 | 中冶华天南京电气工程技术有限公司 | Verifying attachment of voltage transformer opening triangle protection |
| CN106646092A (en) * | 2016-12-13 | 2017-05-10 | 中国二冶集团有限公司 | Detection method for secondary system of voltage transformer |
| CN207662990U (en) * | 2017-12-08 | 2018-07-27 | 包头钢铁（集团）有限责任公司 | A kind of detecting system of CT secondary circuits open circuit and virtual connection |
| CN208013377U (en) * | 2018-03-13 | 2018-10-26 | 浙江海洋大学 | Low-voltage circuit breaker voltage monitoring and voltage protection |
Non-Patent Citations (1)
| Title |
|---|
| 电能表中性点虚接对电压互感器二次压降的影响分析;丁涛 等;《电测与仪表》;20091031;正文第43至44页 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN109188181A (en) | 2019-01-11 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| RU2540851C2 (en) | Method for selection of short-circuited phase and determination of short circuit type | |
| CN109188181B (en) | Virtual connection judgment method for neutral line of secondary circuit of power grid voltage transformer | |
| CN107765077B (en) | Magnetizing inrush current identification method and device | |
| CN102393507B (en) | Motor parameter detection method and motor parameter detection device | |
| US11502507B2 (en) | Power converter with ground fault detection function and fault detection method | |
| US10393810B2 (en) | Method for identifying the fault by current differential protection and device thereof | |
| CN108982949B (en) | Method for obtaining phasor of line voltage and phase voltage based on magnitude of line voltage and phase voltage | |
| CN107765076B (en) | Magnetizing inrush current identification method and device | |
| CN105137278A (en) | SOGI-based single-phase transformer short-circuit parameter on-line real-time identification method | |
| CN105067948A (en) | Small-current grounding line selection device and single-phase grounding detection method | |
| CN111141995B (en) | Line double-end steady-state distance measuring method and system based on amplitude comparison principle | |
| CN104730416A (en) | Electric transmission line single-terminal ranging method with sudden change of current as polarizing quantity | |
| CN103399213A (en) | Calculation method for dielectric loss factor of high-voltage electric equipment | |
| CN108414838A (en) | A kind of inverter parallel system line impedance measurement method | |
| CN103424622A (en) | Detecting and determining method of fractional harmonic source | |
| CN107167707A (en) | A kind of double circuit lines distance-finding method and device based on unknown parameters | |
| CN107797017B (en) | Method for detecting loss characteristic parameters of power transformer in live mode | |
| CN107179476B (en) | Distribution network fault distance measurement method | |
| CN102735993B (en) | Double-end distance measurement method used in line protection | |
| CN117148256A (en) | Method, device, equipment and storage medium for checking load of transformer substation | |
| CN104979808B (en) | A kind of inverter calculation of penetration level method counted and longitudinal difference protection influences | |
| US11808794B2 (en) | Method and device for approximately determining voltages at a high-voltage side of a transformer | |
| JP4921246B2 (en) | Ground fault distance relay | |
| CN104345218A (en) | Reactance value measurement system and method for three-phase reactor | |
| CN109799426B (en) | Line instantaneous fault positioning method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |