CN111614061B - Locking method for differential protection of series transformer - Google Patents
Locking method for differential protection of series transformer Download PDFInfo
- Publication number
- CN111614061B CN111614061B CN202010462000.9A CN202010462000A CN111614061B CN 111614061 B CN111614061 B CN 111614061B CN 202010462000 A CN202010462000 A CN 202010462000A CN 111614061 B CN111614061 B CN 111614061B
- Authority
- CN
- China
- Prior art keywords
- series transformer
- current
- differential protection
- current sampling
- series
- 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
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/04—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for transformers
- H02H7/045—Differential protection of transformers
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R35/00—Testing or calibrating of apparatus covered by the other groups of this subclass
- G01R35/02—Testing or calibrating of apparatus covered by the other groups of this subclass of auxiliary devices, e.g. of instrument transformers according to prescribed transformation ratio, phase angle, or wattage rating
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H1/00—Details of emergency protective circuit arrangements
- H02H1/0007—Details of emergency protective circuit arrangements concerning the detecting means
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Emergency Protection Circuit Devices (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Protection Of Transformers (AREA)
Abstract
The invention discloses a locking method for series transformer differential protection, which comprises the following steps: step 1, respectively collecting the current I of the head end of the series winding of the series transformer1Current I at the tail end of the series winding2Parallel winding bushing current I3(ii) a Step 2, taking IiCurrent sampling points and all sampling points in a T time period prior to the current sampling points form data samples Ai, i is 1,2 and 3; step 3, respectively determining I1、I2、I3Inflection point flag and zero crossing flag of; step 4, setting a bypass attenuation state flag F of the series transformer to be 1 or 0 according to values of the inflection point flag and the zero-crossing flag; if the current sampling time F is 1, t is after the current sampling timeset2The differential protection is locked out during the time period. The locking method can solve the problem of differential protection misoperation caused by inconsistent current attenuation characteristics when the bypass of the series transformer is switched on.
Description
Technical Field
The invention belongs to the field of relay protection of a power system, and particularly relates to a locking method for differential protection of a series transformer.
Background
The series transformer adopts a bypass switch-on mode to isolate the transformer. When the series transformer normally operates, the bypass switch is in an open circuit state, and at the moment, the current flowing through the grid side winding of the series transformer is the line tide. When the bypass switch is switched on, the two ends of the series transformer winding are completely short-circuited.
Because the transformer belongs to an inductive component, when the series transformer winding is short-circuited, the current in the series transformer winding cannot change suddenly, and an attenuated direct-current component is formed. The attenuated dc component may pass through the protection device CT, and then may have a zero crossing phenomenon of the attenuated current. Because the attenuation time constants of all sides of the series transformer are different, when the zero crossing phenomenon occurs on the network side and the valve side and the zero crossing phenomenon is asynchronous, the differential flow can be calculated through the differential protection of the series transformer. At this time, since the braking current is not large, the differential protection is easy to meet the action characteristic curve, and further, the misoperation risk exists.
In the prior art, the study on the transmission and transformation of the CT is mainly focused on the influence of the saturation of the CT and the broken line of the CT on the differential protection, and the study on the direct current component of the transmission and transformation of the CT is not related, because the fault is isolated by the tripping mode of a breaker of a conventional transformer, the breaker has an arc extinguishing function, and the broken current can disappear instantly after the switch is tripped, so the transmission and transformation characteristic of the direct current component of the transmission and transformation of the CT is not required to be considered.
The differential protection circuit is used for solving the problem that when a series transformer adopts a bypass switching-on isolation mode, the differential protection is affected by the transmission characteristic difference when a direct current component is transmitted and converted by a CT.
Disclosure of Invention
The invention aims to provide a locking method for differential protection of a series transformer, which can solve the problem of differential protection misoperation caused by inconsistent current attenuation characteristics when a bypass of the series transformer is switched on.
In order to achieve the above purpose, the solution of the invention is:
a locking method for series transformer differential protection comprises the following steps:
step 1, respectively collecting the current I of the head end of the series winding of the series transformer1Tail end current of series winding I2Parallel winding bushing current I3；
Step 2, taking I1The current sampling point and all sampling points in a time period T prior to the current sampling point form a data sample A1; get I2The current sampling point and all sampling points in a time period T prior to the current sampling point form a data sample A2; get I3The current sampling point and all sampling points in a time period T prior to the current sampling point form a data sample A3;
step 3, respectively determining I1、I2、I3Inflection point sign f of1、f2、f3And zero crossing flag z1、z2、z3The value is 0 or 1;
step 4, according to f1、f2、f3、z1、z2、z3Setting a bypass attenuation state flag F of the series transformer to be 1 or 0; if the current sampling time F is 1, starting from the current sampling time After that, tset2The differential protection is locked out during the time period.
In the step 2, the value range of T is that T is more than or equal to 10 ms.
In the step 3, the method for determining the inflection point marker includes: and solving the maximum value and the minimum value of instantaneous values of all sampling points in the data sample Ai, if the conditions are met: "the maximum value is neither the 1 st nor the last 1 of the data samples Ai, or the minimum value is neither the 1 st nor the last 1 of the data samples Ai", then I is setiInflection point sign f ofiIs 1, otherwise f is setiIs 0, i is 1,2, 3.
In step 3, the method for determining the zero-crossing flag includes: if the condition is satisfied: "the product of the maximum value and the minimum value of the data samples Ai is negative number or 0", then set IiZero crossing flag z ofiIs 1, otherwise, z is setiIs 0, i is 1,2, 3.
In the step 4, if the condition is satisfied: ' f1、f2、f3、z1、z2、z3Are all 0 and last for a time exceeding a set time constant value tset1If yes, the bypass attenuation state flag F of the series transformer is set to be 1, otherwise, the bypass attenuation state flag F is set to be 0.
The above-mentioned set time constant value tset1The value range is as follows: t is tset1≥10ms。
T aboveset2The value range is as follows: t is tset2≤10s。
After the scheme is adopted, the characteristic of each CT sampling value of the series transformer is utilized to judge whether the series transformer is in a bypass attenuation state, and therefore misoperation of the differential protection of the series transformer when the current attenuation passes through zero is prevented.
Drawings
Fig. 1 is a flow chart of a locking method of a series transformer differential protection according to the present invention.
Fig. 2 is a diagram of a series transformer configuration and CT installation.
Detailed Description
The technical solution and the advantages of the present invention will be described in detail with reference to the accompanying drawings.
As shown in fig. 1, the present invention provides a locking method for series transformer differential protection, which comprises the following steps:
(1) collecting the current I at the head end of the series winding of the series transformer1Current I at the tail end of the series winding2Parallel winding bushing current I3FIG. 2 is a diagram of a series transformer configuration and CT installation;
(2) get I1Current sampling point and all sampling points in T time period prior to the current sampling point form a data sample 1, and I is taken2Current sampling point and all sampling points in T time period prior to the current sampling point form a data sample 2, and I is taken3The current sampling point of the current and all sampling points in a time period T prior to the current sampling point form a data sample 3, the value range of T is more than or equal to 10ms, and T is preferably 20 ms;
(3) and solving the maximum value and the minimum value of instantaneous values of all sampling points in the data sample 1, if the conditions are met: "the sample point where the maximum value is located is neither the 1 st sample point of the data sample 1 nor the last 1 sample point of the data sample 1, or the sample point where the minimum value is located is neither the 1 st sample point of the data sample 1 nor the last 1 sample point of the data sample 1", then set I 1Inflection point sign f1Is 1, otherwise f is set1Is 0;
if the data sample 1 has 5 sampling points in total, which are (-5, -4, -2, -5,1,5), the maximum value of the data sample 1 is 5, and the minimum value is-5; since the minimum value of-5 occurs at both the 1 st and 4 th sample points, I is neither the 1 st nor the last 1 sample point of data sample 1 for the 4 th sample point1Inflection point sign f of1Is 1;
(4) and solving the maximum value and the minimum value of instantaneous values of all sampling points in the data sample 2, if the conditions are met: "the sample point at which the maximum value is located is neither the 1 st sample point of the data sample 2 nor the last 1 sample point of the data sample 2, or the sample point at which the minimum value is located is neither a data sampleIf the 1 st sampling point of this 2 is not the last 1 sampling point of the data sample 2, set I2Inflection point sign f of2Is 1, otherwise f is set2Is 0;
(5) and solving the maximum value and the minimum value of instantaneous values of all sampling points in the data sample 3, if the conditions are met: "the sample point where the maximum value is located is neither the 1 st sample point of the data sample 3 nor the last 1 sample point of the data sample 3, or the sample point where the minimum value is located is neither the 1 st sample point of the data sample 3 nor the last 1 sample point of the data sample 3", then set I 3Inflection point sign f3Is 1, otherwise set f3Is 0;
(6) if the condition is satisfied: "the product of the maximum value and the minimum value of the data sample 1 is negative or 0", set I1Zero crossing flag z of1Is 1, otherwise, z is set1Is 0;
taking data sample 1 as an example, the maximum value of data sample 1 is 5, the minimum value is-5, and the product of the two is-25, so I1Zero crossing flag z of1Is 1;
(7) if the condition is satisfied: "the product of the maximum value and the minimum value of data sample 2 is negative or 0", set I2Zero crossing flag z of2Is 1, otherwise, z is set2Is 0;
(8) if the condition is satisfied: "the product of the maximum value and the minimum value of the data sample 3 is negative or 0", set I3Zero crossing flag z of3Is 1, otherwise, z is set3Is 0;
(9) if the condition is satisfied: ' f1、f2、f3、z1、z2、z3Are all 0 and last for a time exceeding a set time constant value tset1", the bypass attenuation status flag F of the series transformer is set to 1, otherwise, F is set to 0, tset1The value range is as follows: t is tset1More than or equal to 10ms, t is recommendedset1Preferably 40 ms;
(10) if the current sampling time F is 1, starting from the current sampling time, t is after the current sampling timeset2For locking differential protection, tset2The value range is as follows: t is tset2≤10s。
The above embodiments are only for illustrating the technical idea of the present invention, and the protection scope of the present invention is not limited thereby, and any modifications made on the basis of the technical scheme according to the technical idea of the present invention fall within the protection scope of the present invention.
Claims (6)
1. A locking method for series transformer differential protection is characterized by comprising the following steps:
step 1, respectively collecting the current I of the head end of the series winding of the series transformer1Current I at the tail end of the series winding2Parallel winding bushing current I3；
Step 2, taking I1The current sampling point and all sampling points in a time period T prior to the current sampling point form a data sample A1; get I2The current sampling point and all sampling points in a time period T prior to the current sampling point form a data sample A2; get I3The current sampling point and all sampling points in a time period T prior to the current sampling point form a data sample A3;
step 3, respectively determining I1、I2、I3Inflection point sign f of1、f2、f3And zero crossing flag z1、z2、z3The value is 0 or 1;
in step 3, the method for determining the inflection point marker includes: and solving the maximum value and the minimum value of instantaneous values of all sampling points in the data sample Ai, if the conditions are met: "the maximum value is neither the 1 st nor the last 1 of the data samples Ai, or the minimum value is neither the 1 st nor the last 1 of the data samples Ai", then I is set iInflection point sign fiIs 1, otherwise set fiIs 0, i-1, 2, 3;
step 4, according to f1、f2、f3、z1、z2、z3Setting a bypass attenuation state flag F of the series transformer to be 1 or 0; if the current sampling time F is1, t after the current sampling timeset2The differential protection is locked out during the time period.
2. A method of latching a series transformer differential protection circuit according to claim 1, wherein: in the step 2, the value range of T is that T is more than or equal to 10 ms.
3. A method of blocking differential protection of a series transformer according to claim 1, characterized by: in step 3, the method for determining the zero-crossing flag is as follows: if the condition is satisfied: "the product of the maximum value and the minimum value of the data samples Ai is negative number or 0", then set IiZero crossing flag z ofiIs 1, otherwise, z is setiIs 0, i is 1,2, 3.
4. A method of blocking differential protection of a series transformer according to claim 1, characterized by: in the step 4, if the condition is satisfied: ' f1、f2、f3、z1、z2、z3Are all 0 and last for a time exceeding a set time constant value tset1If yes, the bypass attenuation state flag F of the series transformer is set to be 1, otherwise, the bypass attenuation state flag F is set to be 0.
5. A method of blocking differential protection of a series transformer according to claim 4, characterized by: the set time constant value t set1The value range of (A) is as follows: t is tset1≥10ms。
6. A method of latching a series transformer differential protection circuit according to claim 1, wherein: said t isset2The value range is as follows: t is tset2≤10s。
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010462000.9A CN111614061B (en) | 2020-05-27 | 2020-05-27 | Locking method for differential protection of series transformer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010462000.9A CN111614061B (en) | 2020-05-27 | 2020-05-27 | Locking method for differential protection of series transformer |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN111614061A CN111614061A (en) | 2020-09-01 |
| CN111614061B true CN111614061B (en) | 2022-06-28 |
Family
ID=72197921
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010462000.9A Active CN111614061B (en) | 2020-05-27 | 2020-05-27 | Locking method for differential protection of series transformer |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111614061B (en) |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101615783A (en) * | 2009-07-31 | 2009-12-30 | 西安交通大学 | Zero-sequence current longitudinal differential protection method based on star-connection delta line transformer |
| CN101820185A (en) * | 2009-02-26 | 2010-09-01 | 西北电网有限公司 | Power grid fault judgment method based on IEC61850 signal semantic logic |
| CN106569163A (en) * | 2015-10-08 | 2017-04-19 | 南京南瑞继保电气有限公司 | Method for detecting trailing amount of transformer |
| CN107101984A (en) * | 2017-05-18 | 2017-08-29 | 广东顺德工业设计研究院(广东顺德创新设计研究院) | Signal waveform characteristic detection method, device, storage medium and computer equipment |
| CN108695823A (en) * | 2018-06-26 | 2018-10-23 | 南京南瑞继保电气有限公司 | A kind of differential protection blocking method of series transformer tail currents |
| CN110119696A (en) * | 2019-04-26 | 2019-08-13 | 三峡大学 | Current transformer tail currents recognizer based on wave character difference |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9577623B2 (en) * | 2013-09-09 | 2017-02-21 | Microchip Technology Inc. | Capacitive parametric zero crossing detector device, circuit and method |
| US10338119B2 (en) * | 2016-08-16 | 2019-07-02 | Kohler Co. | Generator waveform measurement |
-
2020
- 2020-05-27 CN CN202010462000.9A patent/CN111614061B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101820185A (en) * | 2009-02-26 | 2010-09-01 | 西北电网有限公司 | Power grid fault judgment method based on IEC61850 signal semantic logic |
| CN101615783A (en) * | 2009-07-31 | 2009-12-30 | 西安交通大学 | Zero-sequence current longitudinal differential protection method based on star-connection delta line transformer |
| CN106569163A (en) * | 2015-10-08 | 2017-04-19 | 南京南瑞继保电气有限公司 | Method for detecting trailing amount of transformer |
| CN107101984A (en) * | 2017-05-18 | 2017-08-29 | 广东顺德工业设计研究院(广东顺德创新设计研究院) | Signal waveform characteristic detection method, device, storage medium and computer equipment |
| CN108695823A (en) * | 2018-06-26 | 2018-10-23 | 南京南瑞继保电气有限公司 | A kind of differential protection blocking method of series transformer tail currents |
| CN110119696A (en) * | 2019-04-26 | 2019-08-13 | 三峡大学 | Current transformer tail currents recognizer based on wave character difference |
Non-Patent Citations (1)
| Title |
|---|
| 基于压流波形特征的变压器继电保护的研究;陈剑;《中国优秀博硕士学位论文全文数据库(硕士)工程科技Ⅱ辑》;20021215;全文 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN111614061A (en) | 2020-09-01 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN101540501B (en) | Ground electrode circuit protective system and device of high-voltage DC transmission system | |
| WO2018076431A1 (en) | Short-circuit failure current limiter | |
| CN109936121B (en) | 110kV single-bus sectional wiring bus differential protection locking backup power automatic switching protection method | |
| CN109245072B (en) | Self-adaptive in-situ feeder automation fault processing method based on regional sequence number | |
| CN212137282U (en) | Be suitable for lightning protection circuit of low residual voltage of large capacity | |
| CN111614061B (en) | Locking method for differential protection of series transformer | |
| CN105954563A (en) | Method of identifying tail current based on current derivative and differential current zero-crossing | |
| Sporn et al. | Ultrahigh-speed reclosing of high-voltage transmission lines | |
| CN109861181B (en) | Relay protection method for eliminating dead zone faults of sectional and bus-coupled circuit breakers | |
| CN109830942B (en) | Locking reverse closing method based on voltage abrupt change and three-sequence component asymmetry | |
| CN109245068B (en) | Neutral point grounding mode conversion device | |
| EP1213813A2 (en) | Protection device for low voltage networks | |
| CN114156842B (en) | Self-adaptive arc extinction time reclosing method for true bipolar flexible direct power transmission line | |
| CN108493954A (en) | A kind of micro- auxiliary switching-in system of shoving of shunt capacitor | |
| CN112557888B (en) | Position judging system and method for control switch of controllable lightning arrester | |
| CN110323725B (en) | DC line sampling current correction method, differential protection method and system | |
| CN106324328A (en) | Morphological cascade erosion operation-based voltage transformer magnetizing rush current identification method | |
| CN106169737B (en) | High current starts the simple bus protection relay protecting method of 500kV substation 35kV | |
| CN117767223A (en) | Device and method for inhibiting fault energy in converter transformer based on superconducting current limiter | |
| CN111446126B (en) | Switching device | |
| CN112510658B (en) | Multi-power-point 10kV line feeder automation method with high power supply reliability | |
| CN103337833B (en) | A kind of method of grounded transformer protection action | |
| US11342742B2 (en) | Set of electrical protection devices with two levels that are connected in series | |
| CN211266460U (en) | Phase selection breaking device and circuit breaker | |
| CN217469445U (en) | Electrified railway station territory protection measurement and control device and system |
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 |