CN112803368B - 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 PDFInfo
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- CN112803368B CN112803368B CN202011628412.1A CN202011628412A CN112803368B CN 112803368 B CN112803368 B CN 112803368B CN 202011628412 A CN202011628412 A CN 202011628412A CN 112803368 B CN112803368 B CN 112803368B
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- 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
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- 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
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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
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 pieces of electrical equipment. When a power transformer is switched on, a magnetizing inrush current is generated in a winding of the transformer at a high probability due to the saturation characteristic 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 no-load closing magnetizing inrush current after a 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 no-load. 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 = A or B or C;
s3, determining a closing angle according to the phase X
The method aims at restraining the most easily saturated phase magnetizing inrush current;
s4, delaying t ys Sending a closing signal to control a contact of the breaker to be at the closing angle
Is closed.
Further, step S1 specifically includes:
s11, detecting three-phase instantaneous current i of transformer in real time A ，i B ，i C ；
S12. When i A ＜i set ∩i B ＜i set ∩i C ＜i set When it is determined that the transformer is switched off, wherein i set Is 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 opening Arms ，I Brms ，I Crms ；
S22, comparison I Arms ，I Brms ，I Crms And obtaining the maximum phase X of the three-phase no-load current.
Further, step S3 specifically includes:
s31, if X = A, then
Or 270 °;
s32, if X = B, then
Or 210 °;
s33, if X = C, then
Or 330.
Further, step S4 specifically includes:
s41, using a least square method to fit historical data and predicting action time t of the breaker dlq ；
S42, considering the outlet time t of the relay jdq And circuit breaker operating time t dlq Calculating the time delay t ys Sending a closing signal;
s43, the breaker is at a closing angle
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 time dlq_i ；
At calculation of the delay t ys Before, use least square method, with the latest ten actual action time t of breaker dlq_i (i = 1.. 10.) as a sample, the circuit breaker action time of the next closing is predicted
As follows:
wherein, the first and the second end of the pipe are connected with each other,
the invention considers that the saturation characteristics of three-phase windings of the transformer are different, provides a method for detecting 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 a 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.
Compared with the prior art, the technical scheme of the invention can achieve 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 wiring is performed, 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)t jdq : relay outlet delayTime t jdq Typically on the ms level.
2)t dlq_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)i set : and (4) setting a current threshold value, and judging whether the transformer is switched off or not.
And 3, step 3: the device is put into operation, current signals are continuously detected and stored, and a closing angle is calculated after opening
And controlling the time delay t of the switching-on signal ys The method specifically comprises the following steps:
1) Device for collecting three-phase current signal i of transformer A ，i B ，i C ；
2) The current sampling values of continuous half cycles all meet the condition: i.e. i A ＜i set ∩i B ＜i set ∩i C ＜i set Judging the opening of the transformer;
3) Calculating the effective value of the three-phase current before opening: I.C. A Arms ，I Brms ，I Crms ；
4) From I Arms ，I Brms ，I Crms Determining the most easily saturated phase X;
5) If X = A, then
Or 270 °; if X = B, then
Or 210 °; if X = C, then
Or 330.
6) Calculating closing time
7) If the circuit breaker is switched on for the first time, the action time t of the circuit breaker is determined dlq ＝t dlq_set If 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
And order
Wherein, the first and the second end of the pipe are connected with each other,
8) Calculating the time delay of sending a closing signal: t is t ys ＝(N min ×20ms+t hj )-(t jdq +t dlq ) Wherein
And 4, step 4: waiting for a switching-on command and a switching-on stage, as shown in fig. 3, specifically includes:
1) The device waits for an external closing command, if the external closing command is received, the device is set with H =1, and the next step is carried out; if not, keeping H =0, and continuously waiting for a closing command by the device;
2) When H =1, wait for A phase voltage
Changing the time from negative to positive and recording the time as a time starting point t 0 ；
3) Device monitoring t-t 0 ≥t ys If the condition is met, wherein t is the current moment, when the condition is met, the device sends a closing signal, and the device delays t through the inherent delay of the relay jdq The circuit breaker receives closing pulse and passes through the inherent mechanical delay t of the circuit breaker dlq The 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 (6)
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 with the three-phase no-load current, and determining the maximum phase of the no-load current, wherein the maximum phase of the no-load current is the phase A, the phase B or the phase C of the three-phase transformer;
s3, determining a closing angle according to the maximum phase of the no-load current
If the maximum phase of the no-load current is A phase, then
Or 270 °; if the maximum phase of no-load current is B phase, then
Or 210 °; if the maximum phase of no-load current is C phase, then
Or 330 °;
s4, calculating the delay t ys Sending a closing signal to control a contact of the breaker to be at the closing angle
Is closed.
2. The method for suppressing according to claim 1, wherein the step S1 specifically includes:
s11, detecting three-phase instantaneous current i of the transformer in real time A ,i B ,i C ；
S12. When i A <i set ∩i B <i set ∩i C <i set When the transformer is switched off, i set Is a setting value.
3. The method for suppressing 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 opening Arms ,I Brms ,I Crms ；
S22, comparison I Arms ,I Brms ,I Crms And obtaining the maximum phase of the three-phase no-load current.
4. The method for suppressing 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 breaker dlq ；
S42, considering the time t of the relay outlet jdq And circuit breaker operating time t dlq Calculating the time delay t ys Sending a closing signal;
s43, the breaker is at a closing angle
Is closed.
5. The method of suppressing according to claim 4, 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 time dlq_i ；
At calculation of the delay t ys First, using least square method, with the latest ten actual action time t of the breaker dlq_i For the sample, i =1, \ 8230;, 10, the circuit breaker operation time of the next closing is predicted
As follows:
6. 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 5.
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| 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 |
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| 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 |
Citations (3)
| 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 |
| 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 |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5343118B2 (en) * | 2011-12-07 | 2013-11-13 | 株式会社興電舎 | Excitation current suppression device |
| 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 |
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Patent Citations (3)
| 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 |
| 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 |
Non-Patent Citations (1)
| Title |
|---|
| 台山电厂升压变压器励磁涌流分析及其抑制手段;钟文华;《工程科技Ⅱ辑》;20140530;第C042-188页 * |
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