CN104410043B - A kind of method for improving transformer differential protection sensitivity - Google Patents
A kind of method for improving transformer differential protection sensitivity Download PDFInfo
- Publication number
- CN104410043B CN104410043B CN201410713803.1A CN201410713803A CN104410043B CN 104410043 B CN104410043 B CN 104410043B CN 201410713803 A CN201410713803 A CN 201410713803A CN 104410043 B CN104410043 B CN 104410043B
- Authority
- CN
- China
- Prior art keywords
- transformer
- current
- formula
- voltage
- electric 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.)
- Active
Links
- 238000000034 method Methods 0.000 title claims abstract description 16
- 230000035945 sensitivity Effects 0.000 title claims abstract description 11
- 238000004364 calculation method Methods 0.000 claims description 30
- 238000000205 computational method Methods 0.000 description 5
- 230000001105 regulatory effect Effects 0.000 description 5
- 230000005611 electricity Effects 0.000 description 3
- 230000007257 malfunction Effects 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000008030 elimination Effects 0.000 description 1
- 238000003379 elimination reaction Methods 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 238000005457 optimization Methods 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
- 238000005303 weighing Methods 0.000 description 1
Abstract
The invention discloses a kind of method for improving transformer differential protection sensitivity; using transformer differential protection fault distinguishing program; each side electric current of transformer, voltage are gathered by current transformer, voltage transformer first; each side electric current is multiplied by this lateral balance coefficient calculated according to virtual voltage, transformer rated capacity, CT no-load voltage ratios again to be converted; enter line transformer differential current computing again afterwards; then carry out differing from the judgement of stream operation condition; meet condition and then send transformer trip signal and be simultaneously emitted by warning information, otherwise just exit fault distinguishing program.This method enters the calculating of each lateral balance coefficient of line transformer using the virtual voltage of each side of transformer for collecting; rather than the calculating for entering each lateral balance coefficient of line transformer using each side rated voltage of transformer; so as to eliminate actual motion voltage the error for causing is differed with rated voltage; the minimum working current of transformer differential protection is effectively reduced, so as to improve the sensitivity of transformer differential protection.
Description
Technical field
The present invention relates to tranformer protection technical field, more particularly to a kind of side for improving transformer differential protection sensitivity
Method.
Background technology
At present, the flow of transformer differential protection work is as shown in Figure 1.When transformer differential protection fault distinguishing program is opened
After dynamic, each side electric current of transformer is gathered by current transformer first, then each side electric current is multiplied by according to rated voltage, transformation
This lateral balance coefficient (or being called regulation coefficient) that device rated capacity, CT no-load voltage ratios are calculated is converted, and is carried out again afterwards
Transformer differential current computing, then carries out differing from the judgement whether stream meets operation condition, meets condition and is issued by transformer tripping operation life
Order is simultaneously emitted by warning information, otherwise just exits fault distinguishing program, returns to normal procedure.
It is the reason for being converted before carrying out differential current computing：Each side voltage difference, electric current are mutual during due to transformer station high-voltage side bus
Sensor no-load voltage ratio is different, so, each side electric current for causing transformer differential protection to experience can not be under same standard, it is necessary to pass through
Conversion causes that it is under same standard.Because the factors such as transformer regulating cause actual motion voltage and rated voltage not phase
Together, and change at any time, it is flat when the coefficient of balance that the coefficient of balance computational methods for causing installation current are calculated is with actual motion
Weighing apparatus coefficient is compared error, and then differential current computing is produced error.
One of transformer differential protection operation condition is to differ from stream to have to be larger than minimum working current.To ensure transformer differential
Protection not malfunction, based on current coefficient of balance computational methods, the minimum working current of current transformer differential protection must be carried out
It is corresponding to expand, reduce the sensitivity of differential protection.The minimum working current computational methods master of current transformer differential protection
To use formula (1)：
Iop.min=Krel(Ker+ΔU+Δm)Ie (1)
In formula：IeIt is transformer secondary rated current；KrelIt is safety factor；KerIt is the ratio error (0.06 of current transformer
And following)；The error (5%-10%) that Δ U causes for transformer regulating；Δ m is because current transformer ratio is not matched completely
The error (generally taking 0.05) of generation.Δ U in formula is exactly that the minimum working current of current transformer differential protection must be carried out
The corresponding embodiment for expanding.
Because the factors such as transformer regulating cause actual motion voltage and rated voltage and differ, and change at any time, lead
The coefficient of balance for calculating is caused to produce error, and then, for the minimum working current computing formula of above-mentioned transformer differential protection, make
Differential current computing produces error.To avoid this error from causing differential protection malfunction, it is forced to raise the most petty action of transformer differential protection
Make electric current, so as to reduce the sensitivity of differential protection, ultimately result in the generation of related accidents.
The content of the invention
It is an object of the invention to provide a kind of method for improving transformer differential protection sensitivity, the transformer that will be gathered is each
The virtual voltage of side enters the calculating of each lateral balance coefficient of line transformer, and elimination actual motion voltage is differed with rated voltage and caused
Error, effectively protection transformer differential protection minimum working current, so as to improve the spirit of existing transformer differential protection
Sensitivity is high.
The technical solution adopted by the present invention is：
A：First, the actual current and voltage of each side of transformer are gathered respectively by current transformer and voltage transformer；
B：The actual voltage value of each side of transformer gathered according to step A, during each side rated load of calculating transformer one
Secondary actual motion electric current I, as formula 1. shown in：
①
S in formulanIt is the maximum rated capacity of transformer, U is transformer calculation side actual motion voltage；
C：Secondary actual motion electric current during each side rated load of calculating transformer, as formula 2. shown in：
②
Actual motion electric current when I is transformer calculation side rated load in formula, nLHIt is transformer calculation side electric current
Mutual inductor ratio；
D：Each lateral balance coefficient of calculating transformer；
D1：When selected transformer side is used as reference side, the secondary actual motion of transformer reference side rated load
Electric current is I2.j, each lateral balance coefficient of transformer as formula 3. shown in：
③
I in formula2Secondary actual motion electric current during for transformer calculation side rated load, Kjx is connection factor；
D2：Secondary actual motion electric current when side rated load each using transformer is used is used as on the basis of minimum side
During side, when remaining side is amplified successively, each lateral balance coefficient of transformer as formula 4. shown in：
④
Wherein ⑤
I in formula2Secondary actual motion electric current during for transformer calculation side rated load, I2-minFor each side of transformer is specified
The minimum value in secondary actual motion current value during load, I2-maxSecondary actual motion during side rated load each for transformer
Maximum in current value；
D3：When according to current transformer ratio be parameter when, each lateral balance coefficient of calculating transformer, as formula 6. shown in：
⑥
I in formula2Secondary actual motion electric current during for transformer calculation side rated load, INIt is secondary for current transformer
Side rated current, Kjx is connection factor；
E：Based on each lateral balance coefficient of transformer that step D is calculated, transformer differential protection minimum working current is using public
7. formula calculates：
Iop.min=Krel(Ker+Δm)Ie ⑦
In formula：IeIt is transformer secondary rated current；KrelIt is safety factor；KerIt is the ratio error of current transformer；Δm
The error of generation is not matched completely for current transformer ratio；
F：Trip operation condition judgment is carried out according to the transformer differential protection minimum working current value that step E is obtained, if
Meet trip operation current condition, then send transformer trip signal and be simultaneously emitted by warning information；If being unsatisfactory for trip operation electricity
Stream, then exit fault distinguishing program, returns to normal procedure.
The present invention utilizes transformer differential protection fault distinguishing program, is adopted by current transformer, voltage transformer first
Each side electric current of collection transformer, voltage, then each side electric current is multiplied by according to virtual voltage, transformer rated capacity, the calculating of CT no-load voltage ratios
This lateral balance coefficient out is converted, and enters line transformer differential current computing again afterwards, then carries out differing from sentencing for stream operation condition
It is disconnected, meet condition and then send transformer trip signal and be simultaneously emitted by warning information, fault distinguishing program is otherwise just exited, return just
Chang Chengxu.This method enters the calculating of each lateral balance coefficient of line transformer using the virtual voltage of each side of transformer for collecting, and
To enter the calculating of each lateral balance coefficient of line transformer using each side rated voltage of transformer, thus eliminate actual motion voltage with
Rated voltage differs the error for causing, and effectively reduces the minimum working current of transformer differential protection, so as to improve
The sensitivity of transformer differential protection.
Brief description of the drawings
Fig. 1 is transformer differential protection workflow diagram of the invention；
Fig. 2 is the performance chart of transformer differential protection of the invention.
Specific embodiment
As shown in figure 1, the present invention is comprised the following steps：
A：First, the actual current and voltage of each side of transformer are gathered respectively by current transformer and voltage transformer；
B：The actual voltage value of each side of transformer gathered according to step A, during each side rated load of calculating transformer one
Secondary actual motion electric current I, as formula 1. shown in：
①
S in formulanIt is the maximum rated capacity of transformer, U is transformer calculation side actual motion voltage；
C：Secondary actual motion electric current during each side rated load of calculating transformer, as formula 2. shown in：
②
Actual motion electric current when I is transformer calculation side rated load in formula, nLHIt is transformer calculation side electric current
Mutual inductor ratio；
D：Each lateral balance coefficient of calculating transformer；
D1：When selected transformer side is used as reference side, the secondary actual motion of transformer reference side rated load
Electric current is I2.j, each lateral balance coefficient of transformer as formula 3. shown in：
③
I in formula2Secondary actual motion electric current during for transformer calculation side rated load, Kjx is connection factor；
D2：Secondary actual motion electric current when side rated load each using transformer is used is used as on the basis of minimum side
During side, when remaining side is amplified successively, each lateral balance coefficient of transformer as formula 4. shown in：
④
Wherein ⑤
I in formula2Secondary actual motion electric current during for transformer calculation side rated load, I2-minFor each side of transformer is specified
The minimum value in secondary actual motion current value during load, I2-maxSecondary actual motion during side rated load each for transformer
Maximum in current value；
D3：When according to current transformer ratio be parameter when, each lateral balance coefficient of calculating transformer, as formula 6. shown in：
⑥
I in formula2Secondary actual motion electric current during for transformer calculation side rated load, INIt is secondary for current transformer
Side rated current, Kjx is connection factor；
E：Based on each lateral balance coefficient of transformer that step D is calculated, transformer differential protection minimum working current is using public
7. formula calculates：
Iop.min=Krel(Ker+Δm)Ie ⑦
In formula：IeIt is transformer secondary rated current；KrelIt is safety factor；KerIt is the ratio error of current transformer；Δm
The error of generation is not matched completely for current transformer ratio；
F：Trip operation condition judgment is carried out according to the transformer differential protection minimum working current value that step E is obtained, if
Meet trip operation current condition, then send transformer trip signal and be simultaneously emitted by warning information；If being unsatisfactory for trip operation electricity
Stream, then exit fault distinguishing program, returns to normal procedure.
The computational methods that the invention will now be described in detail with reference to the accompanying drawings：
The present invention is directed to three kinds of different situations, is balanced the calculating of coefficient, then carry out transformer differential protection most petty action
Make the calculating of electric current.
The first situation
Certain side of transformer is first selected first as reference side.
Step 1：Gather the virtual voltage U of each side of transformer；Differential protective device of transformer, correlation that this method is used
The acquisition condition such as voltage acquiring method, software and hardware it is completely the same with what existing protection device voltage acquisition was used, herein no longer
Repeat.
Step 2：Actual motion electric current I during each side rated load of calculating transformer, as formula 1. shown in：
①
S in formulanIt is the maximum rated capacity of transformer, U is transformer calculation side actual motion voltage；
Step 3：Secondary actual motion electric current during each side rated load of calculating transformer, as formula 2. shown in：
②
Actual motion electric current when I is transformer calculation side rated load in formula, nLHIt is transformer calculation side electric current
Mutual inductor ratio；
Step 4：When selected transformer side is used as reference side, the secondary actual fortune of transformer reference side rated load
Row electric current is I2.j, each lateral balance coefficient of transformer as formula 3. shown in：
③
I in formula2Secondary actual motion electric current during for transformer calculation side rated load, Kjx is connection factor；
Meanwhile, 1., 2. and 3. the formula of above-mentioned step 2,3 and 4 can be merged, and the fortune such as common divisor of dividing out
Calculate, the formula after a merging is generated, such as shown in formula (2)：
NLH is transformer calculation side current transformer ratio, U calculation side actual motion voltages in formula；nLH.jIt is transformer
Reference side current transformer ratio, UjReference side actual motion voltage.
Step 5：Based on each lateral balance coefficient of transformer that step 4 is calculated, transformer differential protection minimum working current profit
7. calculated with formula：
Iop.min=Krel(Ker+Δm)Ie ⑦
In formula：IeIt is transformer secondary rated current；KrelIt is safety factor；KerIt is the ratio error of current transformer；Δm
The error of generation is not matched completely for current transformer ratio.
Second situation,
Secondary actual motion electric current when using side rated load each using transformer as on the basis of minimum side, remaining
Amplify successively side.
Each lateral balance coefficient of transformer as formula 4. shown in：
④
Wherein ⑤
I in formula2Secondary actual motion electric current during for transformer calculation side rated load, I2-minFor each side of transformer is specified
The minimum value in secondary actual motion current value during load, I2-maxSecondary actual motion during side rated load each for transformer
Maximum in current value；
Remaining step is with the first situation.
The third situation
The specified electricity of secondary side of secondary actual motion electric current and current transformer when transformer calculation side rated load
When stream is compared, actual motion electric current during each side rated load of calculating transformer：
S in formulanIt is the maximum rated capacity of transformer, U is transformer calculation side actual motion voltage.
Secondary actual motion electric current during each side rated load of calculating transformer again：
Actual motion electric current when I is transformer calculation side rated load in formula, nLHIt is transformer calculation side electric current
Mutual inductor ratio.
Each lateral balance coefficient of last calculating transformer：
I in formula2Secondary actual motion electric current during for transformer calculation side rated load, INIt is secondary for current transformer
Side rated current, Kjx is connection factor.
Finally, trip operation condition judgment is carried out according to the transformer differential protection minimum working current value for obtaining, if full
Sufficient trip operation current condition, then send transformer trip signal and be simultaneously emitted by warning information；If being unsatisfactory for trip operation electric current,
Fault distinguishing program is then exited, normal procedure is returned.
The present invention is used and replaces rated voltage with virtual voltage, eliminates the need for error that transformer regulating causes (i.e.：Δ
U), therefore, use the computational methods of transformer differential protection minimum working current of the present invention for：
Iop.min=Krel(Ker+Δm)Ie ⑦
Compared with background technology, error that transformer regulating causes is eliminated (i.e.：ΔU).Transformer differential of the invention
The performance chart of protection, as shown in Figure 2：
In figure：Iop.minIt is transformer differential protection minimum working current；Iop.sdFor transformer differential protection difference flow velocity is disconnected dynamic
Make electric current；Ires.0It is transformer differential protection the minimum restraint current；Ires.maxIt is transformer differential protection maximum stalling current.Make
The minimum working current value calculated with the method for the present invention is smaller than current transformer differential protection minimum working current value.
It is differential protection active region above solid line, lower section is braking area, and protection is failure to actuate.The protection of some producers, it is right
The optimization that this characteristic curve is carried out, such as：Oblique line is changed into the broken line of two sections or three sections, from longitudinal axis Iop.minPlace starts to be put down with transverse axis
Capable first paragraph line segment is changed into being slightly slanted upward oblique line section, can still use in the present invention, is not repeated.
Claims (1)
1. it is a kind of improve transformer differential protection sensitivity method, it is characterised in that：Comprise the following steps：
A：First, the actual current and voltage of each side of transformer are gathered respectively by current transformer and voltage transformer；
B：The actual voltage value of each side of transformer gathered according to step A, it is once real during each side rated load of calculating transformer
Border running current I, as formula 1. shown in：
S in formulanIt is the maximum rated capacity of transformer, U is transformer calculation side actual motion voltage；
C：Secondary actual motion electric current during each side rated load of calculating transformer, as formula 2. shown in：
Actual motion electric current when I is transformer calculation side rated load in formula, nLHIt is transformer calculation side Current Mutual Inductance
Device no-load voltage ratio；
D：Each lateral balance coefficient of calculating transformer；
D1：When selected transformer side is used as reference side, the secondary actual motion electric current of transformer reference side rated load
It is I2.j, each lateral balance coefficient of transformer as formula 3. shown in：
I in formula2Secondary actual motion electric current during for transformer calculation side rated load, Kjx is connection factor；
D2：Secondary actual motion electric current when side rated load each using transformer is used is used as side on the basis of minimum side
When, when remaining side is amplified successively, each lateral balance coefficient of transformer as formula 4. shown in：
Wherein
I in formula2Secondary actual motion electric current during for transformer calculation side rated load, I2-minIt is each side rated load of transformer
When secondary actual motion current value in minimum value, I2-maxSecondary actual motion electric current during side rated load each for transformer
Maximum in value；
D3：When according to current transformer ratio be parameter when, each lateral balance coefficient of calculating transformer, as formula 6. shown in：
I in formula2Secondary actual motion electric current during for transformer calculation side rated load, INIt is the secondary side volume of current transformer
Determine electric current, Kjx is connection factor；
E：Based on each lateral balance coefficient of transformer that step D is calculated, 7. transformer differential protection minimum working current utilizes formula
Calculate：
Iop.min=Krel(Ker+Δm)Ie ⑦
In formula：IeIt is transformer secondary rated current；KrelIt is safety factor；KerIt is the ratio error of current transformer；Δ m is
Current transformer ratio does not match the error of generation completely；
F：Trip operation condition judgment is carried out according to the transformer differential protection minimum working current value that step E is obtained, if meeting
Trip operation current condition, then send transformer trip signal and be simultaneously emitted by warning information；If being unsatisfactory for trip operation electric current,
Fault distinguishing program is exited, normal procedure is returned.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410713803.1A CN104410043B (en) | 2014-11-30 | 2014-11-30 | A kind of method for improving transformer differential protection sensitivity |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410713803.1A CN104410043B (en) | 2014-11-30 | 2014-11-30 | A kind of method for improving transformer differential protection sensitivity |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN104410043A CN104410043A (en) | 2015-03-11 |
| CN104410043B true CN104410043B (en) | 2017-06-27 |
Family
ID=52647648
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201410713803.1A Active CN104410043B (en) | 2014-11-30 | 2014-11-30 | A kind of method for improving transformer differential protection sensitivity |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN104410043B (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105186452B (en) * | 2015-09-10 | 2017-10-31 | 南京国电南自电网自动化有限公司 | A kind of phase-shifting transformer differential protection implementation method |
| CN107167689B (en) * | 2017-05-08 | 2019-06-18 | 合肥工业大学 | Consider the probabilistic short circuit sensitivity computing method of connecting transformer no-load voltage ratio |
| CN108666976B (en) * | 2018-06-07 | 2021-01-05 | 广东科瑞德电气科技有限公司 | Differential protection correction method and system for transformer |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1964149A (en) * | 2006-12-19 | 2007-05-16 | 北京四方继保自动化股份有限公司 | A differential protection method for negative sequence current of large power transformer |
| CN102095965A (en) * | 2009-12-15 | 2011-06-15 | 西安爱邦电气有限公司 | Method for analyzing wiring correctness of CT (current transformer) of two-winding conventional transformer multi-switch differential protection circuit |
| CN102142672A (en) * | 2011-05-05 | 2011-08-03 | 重庆大学 | Current differential protection method for built-in winding mutual inductor of three-phase transformer |
| CN103227452A (en) * | 2012-01-31 | 2013-07-31 | 上海利乾电力科技有限公司 | Computing method of protection fixed value of relay of power plant |
-
2014
- 2014-11-30 CN CN201410713803.1A patent/CN104410043B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1964149A (en) * | 2006-12-19 | 2007-05-16 | 北京四方继保自动化股份有限公司 | A differential protection method for negative sequence current of large power transformer |
| CN102095965A (en) * | 2009-12-15 | 2011-06-15 | 西安爱邦电气有限公司 | Method for analyzing wiring correctness of CT (current transformer) of two-winding conventional transformer multi-switch differential protection circuit |
| CN102142672A (en) * | 2011-05-05 | 2011-08-03 | 重庆大学 | Current differential protection method for built-in winding mutual inductor of three-phase transformer |
| CN103227452A (en) * | 2012-01-31 | 2013-07-31 | 上海利乾电力科技有限公司 | Computing method of protection fixed value of relay of power plant |
Non-Patent Citations (1)
| Title |
|---|
| 主变压器差动保护整定计算详解;常鲜戎等;《江西科学》;20140228;第32卷(第1期);第104-106页 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN104410043A (en) | 2015-03-11 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN102290800B (en) | Method for checking relay protection setting | |
| CN103278746B (en) | Consider the implementation method of the electric network failure diagnosis system of uncertain information | |
| CN104410043B (en) | A kind of method for improving transformer differential protection sensitivity | |
| CN103514364B (en) | The grid equipment overload aid decision computational methods of meter and load transfer measure | |
| CN102882193B (en) | Method and system for traveling wave protection setting of high-voltage direct-current transmission line | |
| CN104242316B (en) | Analytical method and the system of low-frequency and low-voltage cutting load total amount | |
| CN103474972B (en) | A kind of relaying protection on-line setting method | |
| CN105391050B (en) | Cut the check method and system of machine allocation plan high week | |
| CN103337904A (en) | Emergency control method for power grid voltage out-of-limit and equipment overload based on multi-source data | |
| CN106026041B (en) | Longitudinal protection method for flexible direct current interconnect device egress line | |
| CN104240045A (en) | Method for analyzing coordination and safety of protective relaying of regional power grid | |
| CN108681800A (en) | A kind of fortune inspection methods of risk assessment of distributed new access power distribution network | |
| CN102969692A (en) | Branch coefficient calculation method based on real-time data of power grid | |
| CN104578013B (en) | A kind of direction protection method of the power distribution network containing DFIG based on power frequency difference | |
| CN104779608A (en) | Safe stable on-line additional emergency control method of power system based on off-line strategy | |
| CN104300518B (en) | Quick direct current system protection scheme based on voltage source type current converter | |
| CN105243230B (en) | A kind of equivalent modeling method of the directly driven wind-powered field of meter and discharging circuit | |
| CN102253296A (en) | Method for testing comprehensive device of transformer | |
| CN106154025B (en) | A kind of method that combining unit rejects single-point abnormal data | |
| CN105353753A (en) | Protection motion behavior intelligent analysis method based on multisource wave recording files | |
| CN105186467A (en) | Distributed power fault analysis method and protection system | |
| CN106384995A (en) | Differential protection preventing method and differential protection preventing device | |
| CN108493965A (en) | Distribution transformer three-phase imbalance Automatic adjustment method | |
| CN107067126B (en) | Thermal stability key power transmission channel identification method based on power flow transfer ratio | |
| CN102930408A (en) | State evaluation method based on information fusion for secondary equipment of 750 kV power grid |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |