CN104201658B - A kind of differential guard method of transmission line of electricity based on virtual stalling current - Google Patents
A kind of differential guard method of transmission line of electricity based on virtual stalling current Download PDFInfo
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- CN104201658B CN104201658B CN201410476013.6A CN201410476013A CN104201658B CN 104201658 B CN104201658 B CN 104201658B CN 201410476013 A CN201410476013 A CN 201410476013A CN 104201658 B CN104201658 B CN 104201658B
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- 230000005611 electricity Effects 0.000 title claims abstract description 26
- 230000005540 biological transmission Effects 0.000 title claims abstract description 24
- 238000000034 method Methods 0.000 title claims abstract description 15
- 230000009466 transformation Effects 0.000 claims abstract description 5
- 238000010276 construction Methods 0.000 claims abstract description 3
- 230000009471 action Effects 0.000 claims description 7
- 230000035945 sensitivity Effects 0.000 abstract description 9
- 230000007704 transition Effects 0.000 abstract description 3
- 238000010586 diagram Methods 0.000 description 8
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
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Abstract
The invention provides a kind of differential guard method of the transmission line of electricity based on virtual stalling current, this method comprises the following steps：I, obtain the current value of the transmission line of electricity both sides and LPF is carried out to it；II, Fourier transformation is carried out, obtain phasorIII, to the phasorCarry out condenser current compensation；IV, construction virtual current, determine differential protection criterion according to virtual current, judge whether differential protection acts.The disk differential protection criterion that this method provides has good adaptability, troubles inside the sample space high sensitivity, is not influenceed by load current, resistance to transition resistance ability is strong；During external area error, protection is reliably failure to actuate.
Description
Technical field
It is in particular to a kind of based on virtual braking electricity the present invention relates to a kind of method of field of relay protection in power
The differential guard method of transmission line of electricity of stream.
Background technology
Main protection of the current differential protection as circuit, it is used widely in 220kV and above circuit.
The phasor of the general access line both sides electric current of braking amount of transmission line of electricity differential current protection is poor, but by load current shadow
Sound is larger, in heavy load situations in generating region during high resistive fault, the sensitivity decrease of current differential protection, the wind of tripping be present
Danger.
In the prior art, current differential protection uses ratio brake, for braking amount, when restraint coefficient is chosen it is less than normal when,
False protection when may cause external area error, reliability decrease, and influence differential protection internally when restraint coefficient is excessive
Sensitivity during failure.It is significant for improving protective value to choose the braking amount of current differential protection, area can be improved
The sensitivity protected during internal fault, while when ensureing external area error, current differential protection is failure to actuate.
A kind of accordingly, it is desirable to provide current differential protection braking amount selection scheme with adaptation function.
The content of the invention
To overcome above-mentioned the deficiencies in the prior art, it is differential that the present invention provides a kind of transmission line of electricity based on virtual stalling current
Guard method.
Solution is used by realizing above-mentioned purpose：
A kind of differential guard method of transmission line of electricity based on virtual stalling current, it is theed improvement is that：Methods described bag
Include following steps：
I, obtain the current value of the transmission line of electricity both sides and LPF is carried out to it；
II, Fourier transformation is carried out, obtain phasor
III, to the phasorCarry out condenser current compensation；
IV, construction virtual current, determine differential protection criterion according to the virtual current, judge whether differential protection moves
Make.
Further, the step IV comprises the following steps：
S401, the actuating quantity for determining the differential protection, the braking of the differential protection is determined according to the virtual current
Amount；
S402, the differential protection criterion is determined, judge whether differential protection acts according to the differential protection criterion, when
Meet the differential protection criterion, differential protection action, otherwise differential protection is failure to actuate.
Further, in the step S401, the actuating quantity isWherein,Respectively described transmission of electricity
Circuit both sides current phasor value.
Further, in the step S401, determine that the braking amount comprises the following steps：
Step 1, according to the phasorBuild virtual current
Step 2, the braking amount determined according to the virtual current
In formula,Respectively described transmission line of electricity both sides current phasor value；For
Braking amount；K is restraint coefficient；To takeWithTherebetween the greater,To takeWithTherebetween smaller,ForCorresponding electric current phasor,ForCorresponding electric current
Phasor,ForCorresponding electric current phasor.
Further, in the step S402, the differential protection criterion such as following formula is determined： Wherein,For actuating quantity,For the braking
Amount；
Judge whether the differential protection criterion meets, differential protection acts if meeting, otherwise, the differential protection is not
Action.
Further, if circuit is in normal condition or external area error, differential protection is failure to actuate；
If circuit is in troubles inside the sample space, if the actuating quantity is more than the braking amount, differential protection action；If the action
Amount is less than the braking amount, and differential protection is failure to actuate.
Compared with prior art, the invention has the advantages that：
1st, current differential protection criterion provided by the invention has good adaptability, troubles inside the sample space high sensitivity, not by
Load current influences, and resistance to transition resistance ability is strong；During external area error, protection is reliably failure to actuate.
2nd, with the total full current differential Protection criteria of prior artCompare, it is existing during troubles inside the sample space
There are criterion and criterion actuating quantity proposed by the present inventionIt is identical, andCriterion braking amount proposed by the present inventionExisting criterionIt is of the invention as restraint coefficient identical (K=k)
Braking amountSo criterion high sensitivity proposed by the present invention is in existing criterion.
3rd, with the total full current differential Protection criteria of prior artDuring external area error,Work as K=k, criterion proposed by the present invention has identical reliability with existing criterion；As K ＞ k, the present invention
The criterion reliability of proposition is better than existing criterion, while will not reduce the sensitivity of criterion proposed by the present invention.
4th, transmission line of electricity current differential protection provided by the invention is based on virtual current structure braking amount, and troubles inside the sample space is sensitive
Degree is higher than existing differential protection criterion, can be with quick acting, during external area error in high resistance ground, and reliability is better than existing electric current
Differential protection criterion.
5th, transmission line of electricity current differential protection criterion provided by the invention is adjusted without carrying out outside, passes through journey inside device
Sequence realizes automatically, the braking amount of automatic adjusument protection, reaches the quick acting in troubles inside the sample space, reliably motionless during external area error
Make.
Brief description of the drawings
Fig. 1 is the differential protection flow chart of the transmission line of electricity based on virtual stalling current of the present invention；
Fig. 2 is faulty line schematic diagram in the present embodiment；
Fig. 3 is that the differential protection of troubles inside the sample space in the present invention acts phasor diagram；
Fig. 4 is that the differential protection of external area error in the present invention acts phasor diagram；
The differential protection braking amount of the present invention and existing differential protection braking amount comparison schematic diagram when Fig. 5 is troubles inside the sample space.
Embodiment
The embodiment of the present invention is described in further detail below in conjunction with the accompanying drawings.
As shown in figure 1, Fig. 1 is the differential protection flow chart of the transmission line of electricity based on virtual stalling current of the present invention, this hair
It is bright that a kind of differential guard method of transmission line of electricity is provided, by the electric current of alternative route both sides, virtual current is constructed, the electric current is simultaneously
The phase information of larger current side and the amplitude information of smaller current side are remained, is formed and made using virtual current and smaller current
Momentum.The differential protection of transmission line of electricity of the present invention can adaptively adjust the performance of protection, have good adaptivity,
Under the same conditions, during troubles inside the sample space, criterion sensitivity and resistance to transition resistance ability are better than existing criterion to external area error reliability.
Specifically include following steps：
Step 1: gathering the current value of transmission line of electricity both sides and carrying out LPF to it, LPF obtains Im(k) and
In(k)；
Step 2: to ImAnd I (k)n(k) Fourier transformation is carried out, obtains electric current phasor
Step 3: to the phasorCarry out condenser current compensation；
Step 4: judge whether differential protection acts according to differential protection criterion.
In step 2, to ImAnd I (k)n(k) Fourier transformation is carried out, Fourier transform formula is as follows：
In formula, N is sampled point, takes 24；Im(k)、In(k) it is respectively current sampling data after LPF；
Electric current phasor is obtained as the following formulaAmplitude and phase：
In step 3, to phasorCondenser current compensation is carried out, condenser current compensation formula is：
Wherein, Respectively transmit electricity
Circuit both sides voltage phasor value；To protect installation place residual voltage；Xc1、Xc0For positive sequence capacitive reactance, zero sequence capacitive reactance.
Step 4: judge whether differential protection acts according to differential protection criterion.Specifically include following steps：
S401, the actuating quantity for determining the differential protection and braking amount；
S402, the differential protection criterion is determined, judge whether differential protection acts according to the differential protection criterion；
If electric current is normal condition or external area error, differential protection is failure to actuate；
If electric current is troubles inside the sample space, comparison amount and the braking amount, if the actuating quantity is more than the braking amount,
Differential protection acts；If the actuating quantity is less than the braking amount, differential protection is failure to actuate.
During troubles inside the sample space, the braking amount is close to 0, and the actuating quantity is more than the braking amount, and differential protection acts, quickly
Cut off failure；During external area error, for the actuating quantity close to 0, the braking amount is more than the actuating quantity, the differential protection criterion
Reliably, differential protection is failure to actuate.
In step S401, calculateIt is determined thatFor actuating quantity,Respectively institute
State transmission line of electricity both sides current phasor value.
In step S401, the braking amount is determined as the following formula：
In formula,Respectively described transmission line of electricity both sides current phasor value；For
Braking amount；K is restraint coefficient, typically takes 0<K<1；To takeWithTherebetween the greater,To takeWithTherebetween smaller,ForCorresponding electric current phasor,ForCorresponding electric current phasor,ForCorresponding electric current phasor.
In the present embodiment, K is set as 0.4, is comparedWith
WhenWhen, current differential protection action；
WhenWhen, current differential protection is failure to actuate.
Fig. 2 be the present embodiment in faulty line schematic diagram, Em、EnFor circuit both sides equivalent power supply, protection is arranged on 1 and 2
Place, the electric current for flowing through protection 1 and 2 are respectivelyF1 is troubles inside the sample space point, and F2 is external area error point.
Fig. 3 is that the differential protection of troubles inside the sample space acts phasor diagram, during troubles inside the sample space,WithBetween angle be less than 90 °,
As can be seen thatIt is more thanProtection act.
Fig. 4 is that the differential protection of external area error acts phasor diagram, during external area error,WithBetween angle be more than 90 °, can
To find out,It is less thanProtection is failure to actuate.
The differential protection braking amount of the present invention and existing differential protection braking amount comparison schematic diagram when Fig. 5 is troubles inside the sample space,
It can be found that during troubles inside the sample space, differential protection braking amount proposed by the present inventionIt is significantly less than
Existing differential protection braking amountCriterion high sensitivity is in existing criterion.
Finally it should be noted that:Above example is merely to illustrate the technical scheme of the application rather than to its protection domain
Limitation, although the application is described in detail with reference to above-described embodiment, those of ordinary skill in the art should
Understand:Those skilled in the art read the embodiment of application can be still carried out after the application a variety of changes, modification or
Person's equivalent substitution, but these changes, modification or equivalent substitution, are applying within pending claims.
Claims (3)
- A kind of 1. differential guard method of transmission line of electricity based on virtual stalling current, it is characterised in that：Methods described includes following Step：I, obtain the current value of the transmission line of electricity both sides and LPF is carried out to it；II, Fourier transformation is carried out, obtain phasorIII, to the phasorCarry out condenser current compensation；IV, construction virtual current, determine differential protection criterion according to the virtual current, judge whether differential protection acts；The step IV comprises the following steps：S401, the actuating quantity for determining the differential protection, the braking amount of the differential protection is determined according to the virtual current；S402, the differential protection criterion is determined, judge whether differential protection acts according to the differential protection criterion, work as satisfaction The differential protection criterion, differential protection action, otherwise differential protection is failure to actuate；In the step S402, the differential protection criterion such as following formula is determined： Wherein,For actuating quantity,For the braking amount；In formula,Respectively described transmission line of electricity both sides electric current phasor；K is restraint coefficient；To takeWithTherebetween the greater,To takeWithTherebetween smaller,ForCorresponding electric current phasor,ForCorresponding electric current phasor；Judge whether the differential protection criterion meets, differential protection acts if meeting, otherwise, the differential protection is motionless Make.
- 2. the method as described in claim 1, it is characterised in that：In the step S401, the actuating quantity isIts In,Respectively described transmission line of electricity both sides current phasor value.
- 3. the method as described in claim 1, it is characterised in that：If circuit is in normal condition or external area error, differential protection It is failure to actuate；If circuit is in troubles inside the sample space, if the actuating quantity is more than the braking amount, differential protection action；If the actuating quantity is small In the braking amount, differential protection is failure to actuate.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201410476013.6A CN104201658B (en) | 2014-09-17 | 2014-09-17 | A kind of differential guard method of transmission line of electricity based on virtual stalling current |
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| CN201410476013.6A CN104201658B (en) | 2014-09-17 | 2014-09-17 | A kind of differential guard method of transmission line of electricity based on virtual stalling current |
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| CN104201658B true CN104201658B (en) | 2018-01-19 |
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| CN105655993B (en) * | 2016-02-03 | 2019-07-26 | 中国电力科学研究院 | A kind of current differential protection method using A Shi circle theorem |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6518767B1 (en) * | 2000-10-19 | 2003-02-11 | Schweitzer Engineering Laboratories, Inc. | Line differential protection system for a power transmission line |
| CN1627588A (en) * | 2003-12-11 | 2005-06-15 | 北京四方继保自动化有限公司 | Fault discrimination method based on virtual current phase comparison for protecting bus bar system |
| CN1870375A (en) * | 2005-05-24 | 2006-11-29 | 许继集团有限公司 | Method for judging TA saturation |
| CN102856890A (en) * | 2012-09-11 | 2013-01-02 | 中国电力科学研究院 | Adaptive current differential protection method applied to high-compensation-degree series compensation system |
| CN104953560A (en) * | 2014-03-24 | 2015-09-30 | 国家电网公司 | Zero-sequence current differential protection criterion method for power transmission line |
-
2014
- 2014-09-17 CN CN201410476013.6A patent/CN104201658B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6518767B1 (en) * | 2000-10-19 | 2003-02-11 | Schweitzer Engineering Laboratories, Inc. | Line differential protection system for a power transmission line |
| CN1627588A (en) * | 2003-12-11 | 2005-06-15 | 北京四方继保自动化有限公司 | Fault discrimination method based on virtual current phase comparison for protecting bus bar system |
| CN1870375A (en) * | 2005-05-24 | 2006-11-29 | 许继集团有限公司 | Method for judging TA saturation |
| CN102856890A (en) * | 2012-09-11 | 2013-01-02 | 中国电力科学研究院 | Adaptive current differential protection method applied to high-compensation-degree series compensation system |
| CN104953560A (en) * | 2014-03-24 | 2015-09-30 | 国家电网公司 | Zero-sequence current differential protection criterion method for power transmission line |
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Effective date of registration: 20170406 Address after: 100031 Xicheng District West Chang'an Avenue, No. 86, Beijing Applicant after: State Grid Corporation of China Applicant after: China Electric Power Research Institute Applicant after: State Grid Zhejiang Electric Power Company Address before: 100031 Xicheng District West Chang'an Avenue, No. 86, Beijing Applicant before: State Grid Corporation of China Applicant before: China Electric Power Research Institute |
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