CN102005725A - Method for identifying excitation inrush current based on amplitude-comparison criterion - Google Patents
Method for identifying excitation inrush current based on amplitude-comparison criterion Download PDFInfo
- Publication number
- CN102005725A CN102005725A CN2010105942561A CN201010594256A CN102005725A CN 102005725 A CN102005725 A CN 102005725A CN 2010105942561 A CN2010105942561 A CN 2010105942561A CN 201010594256 A CN201010594256 A CN 201010594256A CN 102005725 A CN102005725 A CN 102005725A
- Authority
- CN
- China
- Prior art keywords
- time
- current
- differential
- waveform
- inrush 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
Links
Images
Landscapes
- Emergency Protection Circuit Devices (AREA)
- Protection Of Transformers (AREA)
Abstract
The invention relates to a method for identifying excitation inrush current based on an amplitude-comparison criterion. When duration time as shown in formula I is greater than time T3, time T8 is delayed, time T5 is spread, and a mark of time T3 with respect to formula II exists within the time T5; or when duration time as shown in formula II is greater than time T3, time T8 is delayed, time T5 is spread, and a sampling mark of time T3 with respect to formula I exists within the time T5; and the current is considered as a fault, and the amplitude-comparison criterion is open, wherein epsilon is a threshold value. The method of the invention can be used for avoiding the operation failure or the false operation of transformer protection equipment, and protecting the safe and stable operation of the power system.
Description
Technical field
The present invention relates to discern in a kind of transformer differential protection the method for magnetizing inrush current and fault current.
Background technology
In order to guarantee the safe operation of transformer, must be equipped with differential protection, and the magnetizing inrush current of transformer is the major hidden danger of transformer differential protection malfunction always.
The principle of identification magnetizing inrush current commonly used at present comprises:
Adopt method for waveform identification to differentiate magnetizing inrush current; promptly utilize positive and negative half-wave vector in cycle of differential current and integrated value and the ratio of the integrated value of a cycle differentiate; generally only even-order harmonic or odd harmonic are worked in essence; not from the waveform asymmetric situation of reflected waveform in essence, the erroneous judgement of differential protection has brought certain influence when giving air-drop.
Utilize the waveform symmetry method--waveform degree of asymmetry k value is differentiated magnetizing inrush current and fault, the sample rate of its principle claimed apparatus is higher, and degree of asymmetry k value be subjected to systematic influence difficulty adjust, and when step down side inserts capacitor, be difficult to find suitable k value.
Summary of the invention
The objective of the invention is to, the symmetry of differential current waveform when utilizing fault, the asymmetry of waveform under the magnetizing inrush current situation, symmetric based on waveform time window and waveforms amplitude than width of cloth formula criterion judgement magnetizing inrush current, flow the comparison that the floating threshold value is finished the symmetry of positive and negative half-wave waveform according to difference current sampled value of stream and difference, judge magnetizing inrush current or fault.
In order to realize the foregoing invention purpose, the present invention adopts following technical scheme:
For the magnetizing inrush current waveform of transformer, mainly contain two kinds of wave characters, a kind of is the magnetizing inrush current of being partial to time shaft one side, and positive and negative half-wave is asymmetric, and another kind is symmetric magnetizing inrush current, but waveform itself is asymmetric about the front and back half cycles; Differential current waveform during for fault, a kind of is that another kind is the fault waveform that has the offset straight flow component about the positive and negative half-wave symmetry of front and back half cycles, along with the decay of offset straight flow component, finally reaches about the positive and negative half-wave symmetry of front and back half cycles.
The symmetry of differential current waveform during according to fault, the asymmetry of waveform under the magnetizing inrush current situation is finished than width of cloth criterion and is differentiated magnetizing inrush current and fault waveform.
Utilization than the method for width of cloth criterion identification magnetizing inrush current according to the judgement of shoving of the positive-negative half-cycle symmetry of waveform, as Fig. 1, fault waveform is a sinusoidal symmetry, dotted line is for judging threshold, when differential current sampling greater than time of positive threshold (perhaps less than negative threshold) greater than time T 3, T8 then delays time, time broadening T5 then, if the sampling of the differential current of free T3 is less than negative threshold (perhaps greater than positive threshold) within this time broadening T5, think that then waveform has fault signature, more open than width of cloth criterion.
1) about asking for the method for the poor floating threshold that flows:
The A transformer is in the air-drop process or when having fault to take place, waveform can contain the direct current of big component, consider to remove the influence of offset straight flow component, the waveform at the air-drop magnetizing inrush current is steeper than the waveform edge of fault current simultaneously, earlier differential sample current is carried out calculus of differences
In the formula (1)
Be current differential current sampling,
The sampling of ordering for m before the differential current,
Be the differentiated sample rate current of current differential current;
B considers that minimum interval angle is the situations of 60 degree under the least favorable situation of magnetizing inrush current of high-power transformer, and differentiated differential sample current is carried out integration between the s point;
Be the integrated value between the s point after the differential current difference;
C obtains the floating threshold value that waveform is interrupted, concrete control method according to current integrated value:
2) according to the shove judgement of criterion of current difference stream sampled value and floating threshold: when satisfied
Time greater than time T 3, the T8 that then delays time, time broadening T5 then, free T3 in time broadening T5
Satisfy, then think to have fault signature, more open than width of cloth criterion;
Perhaps
When satisfying
Time greater than time T 3, the T8 that then delays time, time broadening T5 then, free T3 in time broadening T5
Satisfy, then think to have fault signature, more open than width of cloth criterion.
Beneficial effect of the present invention is as follows: utilization of the present invention is judged the magnetizing inrush current method based on the positive and negative half-wave of half cycle before and after the waveform is symmetric than width of cloth formula criterion, be applicable to the electric power system transformer differential protection, for asymmetricly shove, symmetry is shoved reliably locking, it is reliable open to delay time for the fault waveform of district's bias internal DC component; Under the saturated situation of single-side power troubles inside the sample space CT, can reliably open.Guarantee the safe and stable operation of power transformer.
Description of drawings
Fig. 1 judges the schematic diagram of magnetizing inrush current than width of cloth formula criterion for utilization of the present invention.
Fig. 2 handles the result of magnetizing inrush current than width of cloth formula criterion for utilization of the present invention.
Fig. 3 the present invention utilizes the result than width of cloth formula criterion handling failure electric current
Embodiment
With each cycle 40 point sampling is example.
1) transformer is in the air-drop process or when having fault to take place, waveform can contain the direct current of big component, consider to remove the influence of offset straight flow component, the waveform at the air-drop magnetizing inrush current is steeper than the waveform edge of fault current simultaneously, earlier the differential current sampling is carried out 6 calculus of differences
In the formula (1)
Be current differential current sampling,
Be the sampling of preceding 6 points of differential current,
Be the differentiated sample rate current of current differential current.
2) under the least favorable situation of the magnetizing inrush current of consideration high-power transformer, consider the saturated time delay situation of external area error CT simultaneously, differentiated differential current is carried out the integral operation of 8 points
3), obtain the floating threshold value that waveform is interrupted, concrete control method according to current integrated value:
(3)
4) if
4ms satisfies continuously, and then broadening 6ms forms the data window of a 8ms, if there is the continuous 4ms time to satisfy in this data window
, then think to have fault signature, set up than width of cloth criterion.
Perhaps if
4ms satisfies continuously, and then broadening 6ms forms the data window of a 8ms, if there is continuous 4ms to satisfy in the time in this data window
, then think to have fault signature, set up than width of cloth criterion.
Table 1 utilizes than width of cloth criterion identification magnetizing inrush current magnetizing inrush current waveform processing result
| Air-drop relative time (ms) | Judged |
| 10 | Satisfy negative 4ms less than |
| 20 | Do not satisfy positive 4ms greater than |
| 30 | Satisfy negative 4ms less than floating threshold |
| 40 | Do not satisfy positive 4ms greater than |
| 50 | Satisfy negative 4ms less than |
| 60 | Do not satisfy positive 4ms greater than |
| 70 | Satisfy negative 4ms less than |
| 80 | Do not satisfy positive 4ms greater than floating |
| 90 | Satisfy negative 4ms less than |
| 100 | Do not satisfy positive 4ms greater than floating threshold |
| Judged result | Do not satisfy, be judged as magnetizing inrush current, reliable latch-up protection than width of cloth criterion. |
Table 2 utilizes than width of cloth criterion identification magnetizing inrush current the fault waveform result
| Fault relative time (ms) | Judged |
| 10 | Satisfy negative 4ms less than |
| 20 | Satisfy positive 4ms greater than |
| 30 | Satisfy negative 4ms less than floating threshold |
| 40 | Satisfy positive 4ms greater than floating |
| 50 | Satisfy negative 4ms less than floating threshold |
| Judged result | Satisfy than width of cloth criterion, be judged as fault current, action message. |
Claims (1)
1. based on method, it is characterized in that, may further comprise the steps, may further comprise the steps than width of cloth criterion identification magnetizing inrush current:
1) differential sample current is carried out calculus of differences;
In the formula (1)
Be current differential current sampling,
The sampling of ordering for m before the differential current,
Be the differentiated sample rate current of current differential current;
2) differentiated differential sample current is carried out integration between the s point;
3), obtain the floating threshold value that waveform is interrupted, concrete control method according to current integrated value:
4) when
Duration is greater than time T 3, the T8 that then delays time, time broadening T5 then, free T3 in time T 5
Satisfy; Perhaps, when
Duration is greater than time T 3, the T8 that then delays time, time broadening T5 then, free T3 in time T 5
Satisfy; Then think fault signature, more open than width of cloth criterion,
Be default threshold value,
CBe default coefficient.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010105942561A CN102005725B (en) | 2010-12-19 | 2010-12-19 | Method for identifying excitation inrush current based on amplitude-comparison criterion |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010105942561A CN102005725B (en) | 2010-12-19 | 2010-12-19 | Method for identifying excitation inrush current based on amplitude-comparison criterion |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN102005725A true CN102005725A (en) | 2011-04-06 |
| CN102005725B CN102005725B (en) | 2013-04-24 |
Family
ID=43812876
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2010105942561A Active CN102005725B (en) | 2010-12-19 | 2010-12-19 | Method for identifying excitation inrush current based on amplitude-comparison criterion |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN102005725B (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103683198A (en) * | 2013-12-03 | 2014-03-26 | 昆明理工大学 | Excitation surge current fast identification method based on planar adjacent point distances formed by differential current adjacent order difference |
| CN103872646A (en) * | 2014-02-24 | 2014-06-18 | 南京南瑞继保电气有限公司 | Method for preventing wrong differential protection of motor and transformer caused by induced inrush current |
| CN105021920A (en) * | 2015-06-28 | 2015-11-04 | 许继集团有限公司 | Multiple characteristic identification method of excitation inrush current of main transformer |
| CN107294069A (en) * | 2017-07-07 | 2017-10-24 | 上海思源弘瑞自动化有限公司 | Based on the method counted greatly more abnormal than width criterion identification intelligent station |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6483680B1 (en) * | 1999-10-13 | 2002-11-19 | General Electric Co. | Magnetizing inrush restraint method and relay for protection of power transformers |
| CN1967958A (en) * | 2006-10-16 | 2007-05-23 | 北京交通大学 | Waveform sine principle based transformer excitation flow recognition method |
| CN101257208A (en) * | 2007-12-21 | 2008-09-03 | 清华大学 | Method for identifying transformer excitation surge current |
-
2010
- 2010-12-19 CN CN2010105942561A patent/CN102005725B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6483680B1 (en) * | 1999-10-13 | 2002-11-19 | General Electric Co. | Magnetizing inrush restraint method and relay for protection of power transformers |
| CN1967958A (en) * | 2006-10-16 | 2007-05-23 | 北京交通大学 | Waveform sine principle based transformer excitation flow recognition method |
| CN101257208A (en) * | 2007-12-21 | 2008-09-03 | 清华大学 | Method for identifying transformer excitation surge current |
Non-Patent Citations (2)
| Title |
|---|
| 李艺文: "变压器励磁涌流和内部故障识别新判据", 《广西电力》 * |
| 胡玉峰等: "基于采样值差动的励磁涌流鉴别方法", 《中国电机工程学报》 * |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103683198A (en) * | 2013-12-03 | 2014-03-26 | 昆明理工大学 | Excitation surge current fast identification method based on planar adjacent point distances formed by differential current adjacent order difference |
| CN103683198B (en) * | 2013-12-03 | 2017-01-04 | 昆明理工大学 | The excitation surge current method for quickly identifying of consecutive points distance in a kind of plane based on difference current adjacent order difference composition |
| CN103872646A (en) * | 2014-02-24 | 2014-06-18 | 南京南瑞继保电气有限公司 | Method for preventing wrong differential protection of motor and transformer caused by induced inrush current |
| CN103872646B (en) * | 2014-02-24 | 2016-05-25 | 南京南瑞继保电气有限公司 | Prevent from causing with echo surge current the method for generator and transformer differential protection malfunction |
| CN105021920A (en) * | 2015-06-28 | 2015-11-04 | 许继集团有限公司 | Multiple characteristic identification method of excitation inrush current of main transformer |
| CN105021920B (en) * | 2015-06-28 | 2017-10-24 | 许继集团有限公司 | A kind of main transformer excitation surge current multi-feature recognition method |
| CN107294069A (en) * | 2017-07-07 | 2017-10-24 | 上海思源弘瑞自动化有限公司 | Based on the method counted greatly more abnormal than width criterion identification intelligent station |
Also Published As
| Publication number | Publication date |
|---|---|
| CN102005725B (en) | 2013-04-24 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN102005725B (en) | Method for identifying excitation inrush current based on amplitude-comparison criterion | |
| CN104539165B (en) | Capacitive mode for controlled resonant converter detects circuit and method and controlled resonant converter | |
| CN104682432B (en) | The relay failure detection and filter capacitor guard method of photovoltaic combining inverter | |
| EP1229629A3 (en) | Apparatus and method of detecting ground fault of solar power generation system | |
| WO2018032725A1 (en) | Islanding detection method and device for inverter and power supply system | |
| WO2012112750A4 (en) | Triac dimmer detection | |
| CN103916112A (en) | Control method and device for alternating-current solid-state power controller with current limiting function | |
| CN103278727A (en) | Output power-based diagnosis method for open-circuit fault of insulated gate bipolar transistor (IGBT) of three-phase inverter | |
| CN106549360B (en) | A kind of excitation flow recognition method based on zero-sequence current | |
| CN106546809B (en) | It is a kind of based on without filtering phase current sampling circuit control method and device | |
| CN102005726B (en) | Method for identifying magnetizing inrush current and external fault CT (current transformer) saturation based on waveform discontinuous characteristic | |
| CN101303376A (en) | Method and apparatus for compensating voltage zero-cross detection | |
| CN105954563B (en) | The method for identifying tail currents based on electric current derivation and difference current zero crossing | |
| WO2023185189A1 (en) | Power control circuit and control method therefor | |
| CN110988602A (en) | S-transformation-based traveling wave protection method for hybrid direct current transmission line | |
| CN106451369A (en) | Current transformer tail current truncation method in failure protection | |
| CN105977959A (en) | Method for improving stability of direct current restarting system by employing power rotation band | |
| CN205681111U (en) | A kind of novel current-limiting type power flow control system | |
| CN105548805A (en) | Critical impedance method-based bilateral harmonic source identification and localization method | |
| CN101951180A (en) | DC content detection and control circuit for output side of synchronized inverter | |
| CN105896584A (en) | Method of controlling zero sequence voltage through voltage source type converter | |
| CN113098238A (en) | Digital accurate three-phase synchronous signal acquisition and phase-shifting triggering method | |
| CN108020793A (en) | Special power supply exports pulse-detecting circuit and special power supply dead electricity detection method | |
| CN201805364U (en) | Output-side direct current (DC) content detection and control circuit for grid-connected inverter | |
| JP2022540399A (en) | Drive control circuit and home appliance |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant |