CN112803368A - Method and system for inhibiting no-load closing magnetizing inrush current after three-phase transformer demagnetization - Google Patents

Method and system for inhibiting no-load closing magnetizing inrush current after three-phase transformer demagnetization Download PDF

Info

Publication number
CN112803368A
CN112803368A CN202011628412.1A CN202011628412A CN112803368A CN 112803368 A CN112803368 A CN 112803368A CN 202011628412 A CN202011628412 A CN 202011628412A CN 112803368 A CN112803368 A CN 112803368A
Authority
CN
China
Prior art keywords
phase
transformer
closing
inrush current
current
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.)
Granted
Application number
CN202011628412.1A
Other languages
Chinese (zh)
Other versions
CN112803368B (en
Inventor
匡晓云
白雪锋
黄开天
江浪
杨祎巍
陈卫
于杨
尹项根
姚浩
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Huazhong University of Science and Technology
Research Institute of Southern Power Grid Co Ltd
Original Assignee
Huazhong University of Science and Technology
Research Institute of Southern Power Grid Co Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Huazhong University of Science and Technology, Research Institute of Southern Power Grid Co Ltd filed Critical Huazhong University of Science and Technology
Priority to CN202011628412.1A priority Critical patent/CN112803368B/en
Publication of CN112803368A publication Critical patent/CN112803368A/en
Application granted granted Critical
Publication of CN112803368B publication Critical patent/CN112803368B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

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
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H9/00—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection
    • H02H9/001—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection limiting speed of change of electric quantities, e.g. soft switching on or off
    • H02H9/002—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection limiting speed of change of electric quantities, e.g. soft switching on or off limiting inrush current on switching on of inductive loads subjected to remanence, e.g. transformers

Abstract

The invention discloses a method and a system for inhibiting no-load closing magnetizing inrush current after three-phase transformer demagnetization, and belongs to the technical field of transformer magnetizing inrush current inhibition. The method controls the three-phase linkage breaker to close according to a preset angle aiming at the demagnetized transformer, and achieves the purpose of inhibiting the three-phase magnetizing inrush current. The method is characterized in that the saturation degree of the three-phase iron core is judged according to the no-load current, and the optimal closing angle is selected. The method has good inrush current suppression effect and engineering feasibility.

Description

Method and system for inhibiting no-load closing magnetizing inrush current after three-phase transformer demagnetization
Technical Field
The invention belongs to the technical field of transformer magnetizing inrush current suppression, and particularly relates to a method and a system for suppressing no-load closing magnetizing inrush current after three-phase transformer demagnetization.
Background
Power transformers are extremely important and expensive electrical devices. When a power transformer is switched on, a magnetizing inrush current is generated in a winding of the transformer at a high rate due to the saturation characteristics of the ferromagnetic material. The field experience proves that the amplitude of the magnetizing inrush current can reach several times or even more than ten times of the rated current. The magnetizing inrush current can impact the transformer, shorten the service life of the transformer, and cause differential protection malfunction at the same time, resulting in failure of closing the transformer.
The transformer demagnetizes the new transformer to be put into operation or the transformer after major repair and major inspection before operation, and the remanence of the transformer core is zero. Under the working condition, the random no-load transformer has a high probability of generating excitation inrush current.
The reliable suppression of the magnetizing inrush current has very important significance on the safe and reliable operation of a power system, and the suppression scheme of the magnetizing inrush current of the transformer under the working condition is a difficult problem in the industry.
Disclosure of Invention
Aiming at the defects of the prior art, the invention aims to provide a method and a system for inhibiting the no-load closing magnetizing inrush current after the three-phase transformer is demagnetized, and aims to solve the problem of influence of the magnetizing inrush current on a power system.
The invention aims at the demagnetized transformer and inhibits the magnetizing inrush current when the transformer is switched on in a no-load state. In order to achieve the purpose, the invention provides a method for inhibiting no-load closing magnetizing inrush current after three-phase transformer demagnetization, which comprises the following steps:
s1, judging the switching-off time by a current signal of a transformer;
s2, recording three-phase no-load current before the opening moment of the transformer, comparing the three-phase no-load current with the magnitude of the three-phase no-load current, and determining that the maximum phase of the no-load current is X, namely the most easily saturated phase, wherein X is A, B or C;
s3, determining a closing angle according to the phase X
Figure BDA0002879629640000021
The method aims at restraining the most easily saturated phase magnetizing inrush current;
s4, delaying tysSending a closing signal to control a contact of the breaker to be at the closing angle
Figure BDA0002879629640000022
Is closed.
Further, step S1 specifically includes:
s11, detecting three-phase instantaneous current i of transformer in real timeA，iB，iC；
S12. when iA＜iset∩iB＜iset∩iC＜isetWhen the transformer is switched off, isetIs a setting value.
Further, step S2 specifically includes:
s21, calculating the effective value I of the three-phase no-load current according to the three-phase no-load current in the previous period of openingArms，IBrms，ICrms；
S22, comparison IArms，IBrms，ICrmsAnd obtaining the maximum phase X of the three-phase no-load current.
Further, step S3 specifically includes:
s31, if X is equal to A, then
Figure BDA0002879629640000023
Or 270 °;
s32, if X is equal to B, then
Figure BDA0002879629640000024
Or 210 °;
s33, if X ═ C, then
Figure BDA0002879629640000025
Or 330.
Further, step S4 specifically includes:
s41, using a least square method to fit historical data and predicting action time t of the breakerdlq；
S42, considering the outlet time t of the relayjdqAnd circuit breaker operating time tdlqCalculating the time delay tysSending a closing signal;
s43, the breaker is at a closing angle
Figure BDA0002879629640000026
Is closed.
Further, fitting the historical data by using a least square method, and predicting the action time of the circuit breaker specifically comprises the following steps:
recording actual action time t of circuit breaker for closing each timedlq_i；
At calculation of the delay tysBefore, use least square method, with the latest ten actual action time t of breakerdlq_i(i 1.., 10) is a sample, and the action time of the circuit breaker of the next closing is predicted
Figure BDA0002879629640000031
As follows:
Figure BDA0002879629640000032
wherein the content of the first and second substances,
Figure BDA0002879629640000033
the invention considers that the saturation characteristics of three-phase windings of the transformer are different, provides the detection of the three-phase no-load current of the transformer, finds out the phase X with the maximum no-load current, namely the most easily saturated phase X of the iron core, and aims to inhibit the magnetizing inrush current of the phase X when a closing angle is selected, thereby achieving better magnetizing inrush current inhibition effect。
The invention also provides a system for inhibiting the no-load closing magnetizing inrush current after the demagnetization of the three-phase transformer, which comprises the following steps: a computer-readable storage medium and a processor;
the computer-readable storage medium is used for storing executable instructions;
the processor is used for reading the executable instructions stored in the computer readable storage medium and executing the method for restraining the no-load closing magnetizing inrush current after the three-phase transformer is demagnetized.
Through the technical scheme, compared with the prior art, the invention has the following beneficial effects:
(1) the invention provides a scheme for inhibiting the magnetizing inrush current of a demagnetized transformer, which realizes the inhibiting effect of the magnetizing inrush current by controlling a breaker to close at a specified electrical angle;
(2) the method considers the asymmetry of three-phase parameters of the running transformer, judges the most easily saturated phase of the three phases according to the magnitude of no-load current, and selects the optimal closing angle aiming at the most easily saturated phase, so that the inrush current suppression effect is more obvious;
(3) according to the method, the least square method is adopted to fit the action time of the breaker for the last ten times, the action time of the next breaker is predicted, and the control precision is higher;
(4) the invention adopts the linkage switching-on of the three-phase circuit breaker, does not require the on-site circuit breaker to have split-phase operation capability, reduces the requirement on the circuit breaker and has higher feasibility.
Drawings
Fig. 1 is a wiring diagram of a magnetizing inrush current suppressing device according to an embodiment of the present invention;
fig. 2 is a main flow chart of the operation of the magnetizing inrush current suppressing device according to the embodiment of the present invention;
fig. 3 is a schematic diagram illustrating the calculation of the closing pulse delay according to the embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.
Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.
Step 1: according to the attached figure 1, the connection is carried out, and the lines needing to be accessed by the inrush current suppression device are as follows: a PT line on the bus side; a CT line on the transformer side; a circuit breaker closing signal line; an external closing command button line.
Step 2: as shown in fig. 2, setting parameters specifically include:
1)tjdq: delay t at relay outletjdqTypically on the ms level.
2)tdlq_set: the circuit breaker is characterized in that the switching-on action time of the circuit breaker needs manual setting for the first switching-on, and a predicted value is adopted for the subsequent switching-on.
3)iset: and (4) setting a current threshold value, and judging whether the transformer is switched off or not.
And step 3: the device is put into operation, current signals are continuously detected and stored, and a closing angle is calculated after the opening
Figure BDA0002879629640000041
And controlling the time delay t of the switching-on signalysThe method specifically comprises the following steps:
1) device for collecting three-phase current signals i of transformerA，iB，iC；
2) The current sampling values of the continuous half cycles all meet the condition: i.e. iA＜iset∩iB＜iset∩iC＜isetJudging the opening of the transformer;
3) calculating the effective value of the three-phase current before opening the brake: i isArms，IBrms，ICrms；
4) From IArms，IBrms，ICrmsDetermining the most easily saturated phase X;
5) if X is equal to AThen, then
Figure BDA0002879629640000051
Or 270 °; if X is B, then
Figure BDA0002879629640000052
Or 210 °; if X is equal to C, then
Figure BDA0002879629640000053
Or 330.
6) Calculating the closing time
Figure BDA0002879629640000054
7) If the circuit breaker is switched on for the first time, the action time t of the circuit breaker is determineddlq＝tdlq_setIf the actual action time of the breaker is recorded, the actual action time data of the breaker is utilized to predict the next action time of the breaker by using a least square method
Figure BDA0002879629640000055
And order
Figure BDA0002879629640000056
Wherein the content of the first and second substances,
Figure BDA0002879629640000057
8) calculating the time delay of sending a closing signal: t is tys＝(Nmin×20ms+thj)-(tjdq+tdlq) Wherein
Figure BDA0002879629640000058
And 4, step 4: waiting for a closing command and a closing stage, as shown in fig. 3, specifically includes:
1) the device waits for an external closing command, if the device receives the closing command, the device sets H to be 1, and the next step is carried out; if not, keeping H equal to 0, and continuously waiting for a closing command by the device;
2) when H is 1, waiting A phase voltage
Figure BDA0002879629640000059
Changing the time from negative to positive and recording the time as a time starting point t0；
3) Device monitoring t-t0≥tysIf the condition is met, wherein t is the current moment, when the condition is met, the device sends a closing signal, and the closing signal passes through the inherent delay t of the relayjdqThe circuit breaker receives closing pulse and passes through the inherent mechanical delay t of the circuit breakerdlqThe breaker contacts are closed.
4) And finishing the air drop of the transformer.
It will be understood by those skilled in the art that the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the invention, and that any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims (7)

1. A method for suppressing no-load closing magnetizing inrush current after three-phase transformer demagnetization is characterized by comprising the following steps:
s1, judging the switching-off time by a current signal of a transformer;
s2, recording three-phase no-load current before the opening moment of the transformer, comparing the three-phase no-load current, and determining that the maximum phase of the no-load current is X, wherein X is A, B or C;
s3, determining a closing angle according to the phase X
Figure FDA0002879629630000011
S4, delaying tysSending a closing signal to control a contact of the breaker to be at the closing angle
Figure FDA0002879629630000012
Is closed.
2. The suppressing method according to claim 1, wherein the step S1 specifically includes:
s11, detecting in real timeThree-phase instantaneous current i of transformerA，iB，iC；
S12. when iA＜iset∩iB＜iset∩iC＜isetWhen the transformer is switched off, isetIs a setting value.
3. The suppressing method according to claim 1, wherein the step S2 specifically includes:
s21, calculating the effective value I of the three-phase no-load current according to the three-phase no-load current in the previous period of openingArms，IBrms，ICrms；
S22, comparison IArms，IBrms，ICrmsAnd obtaining the maximum phase X of the three-phase no-load current.
4. The suppressing method according to claim 1, wherein the step S3 specifically includes:
s31, if X is equal to A, then
Figure FDA0002879629630000013
S32, if X is equal to B, then
Figure FDA0002879629630000014
S33, if X ═ C, then
Figure FDA0002879629630000015
5. The suppressing method according to claim 1, wherein the step S4 specifically includes:
s41, using a least square method to fit historical data and predicting action time t of the breakerdlq；
S42, considering the outlet time t of the relayjdqAnd circuit breaker operating time tdlqCalculating the time delay tysSending a closing signal;
s43, the breaker is at a closing angle
Figure FDA0002879629630000016
Is closed.
6. The method of suppressing according to claim 5, wherein the predicting the breaker actuation time using least squares fitting the historical data specifically comprises:
recording actual action time t of circuit breaker for closing each timedlq_i；
At calculation of the delay tysBefore, use least square method, with the latest ten actual action time t of breakerdlq_i(i 1.., 10) is a sample, and the action time of the circuit breaker of the next closing is predicted
Figure FDA0002879629630000021
As follows:
Figure FDA0002879629630000022
wherein the content of the first and second substances,
Figure FDA0002879629630000023
7. the utility model provides a suppression system of no-load closing excitation inrush current after three-phase transformer demagnetization which characterized in that includes: a computer-readable storage medium and a processor;
the computer-readable storage medium is used for storing executable instructions;
the processor is used for reading executable instructions stored in the computer readable storage medium and executing the method for suppressing the no-load closing magnetizing inrush current after the three-phase transformer is demagnetized according to any one of claims 1 to 6.
CN202011628412.1A 2020-12-31 2020-12-31 Method and system for inhibiting no-load closing magnetizing inrush current after three-phase transformer demagnetization Active CN112803368B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202011628412.1A CN112803368B (en) 2020-12-31 2020-12-31 Method and system for inhibiting no-load closing magnetizing inrush current after three-phase transformer demagnetization

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202011628412.1A CN112803368B (en) 2020-12-31 2020-12-31 Method and system for inhibiting no-load closing magnetizing inrush current after three-phase transformer demagnetization

Publications (2)

Publication Number Publication Date
CN112803368A true CN112803368A (en) 2021-05-14
CN112803368B CN112803368B (en) 2023-03-14

Family

ID=75808003

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202011628412.1A Active CN112803368B (en) 2020-12-31 2020-12-31 Method and system for inhibiting no-load closing magnetizing inrush current after three-phase transformer demagnetization

Country Status (1)

Country Link
CN (1) CN112803368B (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113889972A (en) * 2021-09-18 2022-01-04 华中科技大学 Method and device for inhibiting no-load closing excitation inrush current of three-phase transformer

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008251282A (en) * 2007-03-29 2008-10-16 Asahi Kasei Chemicals Corp Transformer excitation rush current supression control method, and device therefor
US20130208386A1 (en) * 2011-12-07 2013-08-15 Kodensya co., ltd. Transformer Inrush Current Restraining Control Equipment
CN103701110A (en) * 2014-01-10 2014-04-02 国家电网公司 Alternating current demagnetizing method-based magnetizing rush current inhibiting method
RU2614053C1 (en) * 2016-05-25 2017-03-22 Федеральное государственное бюджетное образовательное учреждение высшего профессионального образования "Кубанский государственный аграрный университет" Method for reducing inrush current of single-phase transformer when re-enabling in idle mode
CN106605344A (en) * 2014-07-02 2017-04-26 维齐马克斯有限公司 Controlled switching devices and method of using the same

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008251282A (en) * 2007-03-29 2008-10-16 Asahi Kasei Chemicals Corp Transformer excitation rush current supression control method, and device therefor
US20130208386A1 (en) * 2011-12-07 2013-08-15 Kodensya co., ltd. Transformer Inrush Current Restraining Control Equipment
CN103701110A (en) * 2014-01-10 2014-04-02 国家电网公司 Alternating current demagnetizing method-based magnetizing rush current inhibiting method
CN106605344A (en) * 2014-07-02 2017-04-26 维齐马克斯有限公司 Controlled switching devices and method of using the same
RU2614053C1 (en) * 2016-05-25 2017-03-22 Федеральное государственное бюджетное образовательное учреждение высшего профессионального образования "Кубанский государственный аграрный университет" Method for reducing inrush current of single-phase transformer when re-enabling in idle mode

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
钟文华: "台山电厂升压变压器励磁涌流分析及其抑制手段", 《工程科技Ⅱ辑》 *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113889972A (en) * 2021-09-18 2022-01-04 华中科技大学 Method and device for inhibiting no-load closing excitation inrush current of three-phase transformer
CN113889972B (en) * 2021-09-18 2022-08-02 华中科技大学 Method and device for inhibiting no-load closing excitation inrush current of three-phase transformer

Also Published As

Publication number Publication date
CN112803368B (en) 2023-03-14

Similar Documents

Publication Publication Date Title
CN109884448B (en) Method for quickly judging turn-to-turn fault of transformer
CN112803368B (en) Method and system for inhibiting no-load closing magnetizing inrush current after three-phase transformer demagnetization
US11307265B2 (en) Earth leakage circuit breaker
US10096993B2 (en) Controlled switching devices and method of using the same
CN110907821A (en) Permanent magnet synchronous motor fault detection method, computer readable storage medium and air conditioner
CN112946530A (en) Transformer turn-to-turn fault and phase identification method and system based on power loss
CN112039020A (en) Method for identifying magnetizing inrush current and faults based on transformer transformation ratio
CN109494684B (en) Transformer excitation inrush current and fault differential current identification method based on babbitt distance algorithm
CN209994095U (en) Transformer closing inrush current suppression device based on reactor
CN109038491B (en) Large power transformer magnetizing inrush current suppression method
CN114372379B (en) Method, device and equipment for evaluating electrical life of contact of mechanical direct current breaker
CN113889972B (en) Method and device for inhibiting no-load closing excitation inrush current of three-phase transformer
CN109742845B (en) Rapid switching-on method of power supply rapid switching-off device based on optimal phase
CN113629676A (en) Method for suppressing magnetizing inrush current and eliminating residual magnetism of transformer
CN108429229B (en) Method for judging excitation inrush current of no-load transformer in phase selection reclosing process of circuit breaker
CN113130235A (en) Intelligent load switch for electric energy meter and control method and fault diagnosis method thereof
WO2019242716A1 (en) Differential protection method and device for ultra-high voltage transformer
CN111413910A (en) Breaker opening and closing control method, device and system
JP3199940B2 (en) Transformer protection relay device
US6693777B1 (en) Method for controlling the operation of a switching device
Dolgicers et al. Usage of inrush current surge for early detection of inter-winding faults
CN105449652B (en) A kind of positive sequence voltage phase control type excitation surge current suppressing method
CN115347533B (en) Method for reducing excitation inrush current of large transformer
KR20150085367A (en) Apparatus for reducing asymmetric fault current using superconducting fault current limiter and method thereof
CN219372016U (en) Excitation surge current suppression 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