CN104779582B - A kind of discrimination method of in tranformer protection and echo surge current and fault current - Google Patents
A kind of discrimination method of in tranformer protection and echo surge current and fault current Download PDFInfo
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Abstract
The invention discloses a kind of in tranformer protection and echo surge current and the discrimination method of fault current, solve it is accurate differentiate transformer fault electric current with and echo surge current problem.When A phase phase spill currentsB phase phase spill currentsWith C phase phase spill currentsIn any phase phase spill current be more than or equal to transformer spill current setting valve Δ I when, the high-pressure side secondary current area S of calculating transformerY high-pressure sidesWith the medium voltage side secondary current area S of transformerY medium voltage sidesPoor Δ S, as high-pressure side secondary current area SY high-pressure sidesWith medium voltage side secondary current area SY medium voltage sidesDifference in areas Δ S be more than the poor setting valve of the current areas of the high-pressure side secondary current area of transformer and the medium voltage side secondary current difference in areas of transformer, and, it is transformer external area error electric current or and echo surge current when high-pressure side secondary current fundamental wave phase angle is less than or equal to 90 degree with medium voltage side secondary current fundamental wave phase angle difference.The present invention can accurately differentiate transformer fault electric current with and echo surge current, it is to avoid the misoperation of transformer differential protection, it is ensured that the normal operation of grid master.
Description
Technical field
It is more particularly to a kind of the present invention relates to the fault current discrimination method in a kind of power system transformer relay protection
The discrimination method of in transformer relay protecting and echo surge current and fault current, transformer can be accurately determined by this method
The fault current property of protection device, reaches the purpose for ensureing transformer safety operation.
Background technology
With high pressure long-distance transmission line Large scale construction and put into operation, the application of high-power transformer increasingly increases
Many, while large capacity transmission is met, also the reliability and quick-action to tranformer protection propose higher requirement.It is differential
Protection is one of main protection scheme of power transformer interior fault, and differential protection is mainly solved two problems：One is to differentiate that excitation is gushed
Stream and fault current；Two are to discriminate between internal fault and external fault.Long-term operating experience shows that transformer differential protection is one
Determine preferably distinguish internal fault and external fault in degree, but also exist in the discriminating of excitation surge current and fault current
Certain the problem of.In recent years, in the process of running, the phenomenon of a lot of air-drop transformers is occurred in that, causes adjacent in parallel or cascade
The accident of transformer differential protection malfunction, the normal operation to main equipment brings very big harm.At present, also without effectively
Differentiate transformer fault electric current with and echo surge current method, the safe operation to high-power transformer brings hidden danger.
The content of the invention
The invention provides a kind of in tranformer protection and echo surge current and the discrimination method of fault current, it is accurate to solve
Differentiate transformer fault electric current with and echo surge current problem, it is to avoid the misoperation of transformer differential protection.
The present invention is to solve above technical problem by the following technical programs：
The discrimination method of a kind of in tranformer protection and echo surge current and fault current, comprises the following steps：
The high-pressure side secondary current sampled value of the first step, the transformer of acquisition Y-Y- Δ wiring patterns, obtains Y-Y- Δs and connects
The medium voltage side secondary current sampled value of the transformer of line style formula, obtains the secondary electricity of low-pressure side of the transformer of Y-Y- Δ wiring patterns
Flow sampled value；
It is second step, the high-pressure side secondary current sampled value, medium voltage side secondary current sampled value and low-pressure side of acquisition is secondary
Current sampling data, carries out differential filtering respectively；
3rd step, by the high-pressure side secondary current sampled value after differential filtering, the medium voltage side secondary current after differential filtering
Low-pressure side secondary current sampled value after sampled value and differential filtering, carries out all-wave Fourier digital filtering, obtains transformation respectively
Device high-pressure side secondary current fundamental voltage amplitude and phase angle, transformer medium voltage side secondary current fundamental voltage amplitude and phase angle, transformer low voltage
Side secondary current fundamental voltage amplitude and phase angle；
The computational methods of high-pressure side secondary current fundamental voltage amplitude and phase angle are：
Sampling number of the high voltage side of transformer secondary current per cycle is first set as N, then high voltage side of transformer secondary current
The current sampling data of sampled point is i (k), k=0,1, and 2 ... N-1, the sampling interval is Δ t；
According to following Fourier transform formula：
Wherein：
The angular frequency of ω-high voltage side of transformer secondary current cycle；
After the sinusoidal coefficients for obtaining fundamental wave, then the plural form of fundametal compoment is：
High-pressure side secondary current fundamental voltage amplitude is：
High-pressure side secondary current fundamental wave phase angle is：
Using above same method, transformer medium voltage side secondary current fundamental voltage amplitude and phase angle, and transformer are calculated
Low-pressure side secondary current fundamental voltage amplitude and phase angle；
4th step, utilize Y- Δ transform methods, adjustment each side current amplitude of transformer and phase angle；By Y-Y- Δ wiring patterns
The high-pressure side secondary current of Y connections of transformer be converted to the high-pressure side secondary current of Δ connection, by Y-Y- Δ wiring patterns
The medium voltage side secondary current of Y connections of transformer be converted to the medium voltage side secondary current of Δ connection, Y-Y- Δ wiring patterns
The low-pressure side secondary current of the Δ connection of transformer is constant；By transformer medium voltage side current amplitude according to transformer voltage ratio convert to
High voltage side of transformer, step down side current amplitude is converted to high voltage side of transformer according to transformer voltage ratio；Thus obtain
After filtering and conversion：High-pressure side A phase secondary currentsHigh-pressure side B phase secondary currentsHigh-pressure side C phase secondary currentsMedium voltage side A phase secondary currentsMedium voltage side B phase secondary currentsMedium voltage side C phase secondary currentsLow-pressure side A phases
Secondary currentLow-pressure side B phase secondary currentsLow-pressure side C phase secondary currents
5th step, the spill current for the tranformer protection for obtaining Y-Y- Δ wiring patterns start setting valve Δ I；6th step, meter
Calculate A phase phase spill currentsB phase phase spill currentsWith C phase phase spill currentsCalculation formula is as follows：
7th step, obtain respectively：The medium voltage side A phases of the high-pressure side A phase secondary current areas and transformer of transformer are secondary
The A phase secondary current difference in areas setting valves S of current areas differenceA；The high-pressure side B phase secondary current areas of transformer and transformer
The B phase secondary current difference in areas setting valves S of medium voltage side B phase secondary current difference in areasB；The high-pressure side C phase secondary currents of transformer
Area and the C phase secondary current difference in areas setting valves S of the medium voltage side C phase secondary current difference in areas of transformerC；8th step, when A phases
Phase spill currentWhen the spill current that amplitude is more than or equal to tranformer protection starts setting valve Δ I, the high-pressure side of calculating transformer
A phase secondary current areas SY high-pressure sides AWith the medium voltage side A phase secondary current areas S of transformerY medium voltage sides APoor Δ Sa, to be used during calculating
High-pressure side A phase secondary currentsMedium voltage side A phase secondary currents
High-pressure side secondary current area SY high-pressure sides AComputational methods be：
Sampling number of the high voltage side of transformer electric current per cycle is first set as N, the electricity of high voltage side of transformer current sample point
Sampled value i (k) is flowed, k=0,1,2 ... N-1, the sampling interval are Δ t, using Rectangular Method, between calculating between two sampled points
Every area, calculation formula is as follows：
ΔS0=i (0) * Δs t；
ΔS1=i (1) * Δs t；
ΔS2=i (2) * Δs t；
……；
ΔSN-1=i (N-1) * Δs t；
The sampled point for obtaining the spill current startup setting valve Δ I moment that phase spill current is more than or equal to tranformer protection is x；
Then y moment high voltage side of transformer A phase secondary current areas：
Medium voltage side A phase secondary current areas SY medium voltage sides AComputational methods be：
Sampling number of the transformer medium voltage side electric current per cycle is first set as N, the electricity of transformer medium voltage side current sample point
Sampled value i (k) is flowed, k=0,1,2 ... N-1, the sampling interval are Δ t, using Rectangular Method, between calculating between two sampled points
Every area, calculation formula is as follows：
ΔS0=i (0) * Δs t；
ΔS1=i (1) * Δs t；
ΔS2=i (2) * Δs t；
……；
ΔSN-1=i (N-1) * Δs t；
The sampled point for obtaining the spill current startup setting valve Δ I moment that phase spill current is more than or equal to tranformer protection is x；
Then y moment transformers medium voltage side A phase secondary current areas：
High-pressure side A phase secondary current areas SY high-pressure sides AWith medium voltage side A phase secondary current areas SY medium voltage sides ADifference in areas be Δ Sa；
9th step, when A phase phase spill currentsWhen the spill current that amplitude is more than or equal to transformer starts setting valve Δ I, together
When calculate high-pressure side A phases secondary current fundamental wave phase angle and medium voltage side A phase secondary current fundamental wave phase angles, the 4th step is used during calculating
High-pressure side A phase secondary currents after adjustmentMedium voltage side A phase secondary currents
Tenth step, as high-pressure side A phase secondary current areas SY high-pressure sides AWith medium voltage side A phase secondary current areas SY medium voltage sides AFace
Product moment Δ SaMore than or equal to A phase secondary current difference in areas setting valves SA, also, high-pressure side A phases secondary current fundamental wave phase angle and middle pressure
It is transformer troubles inside the sample space electric current when side A phase secondary current fundamental waves phase angle difference is more than 90 degree；When high-pressure side A phase secondary currents face
Product SY high-pressure sides AWith medium voltage side A phase secondary current areas SY medium voltage sides ADifference in areas Δ SaAdjusted more than or equal to A phase secondary current difference in areas
Value SA, also, high-pressure side A phases secondary current fundamental wave phase angle is less than or equal to 90 degree with medium voltage side A phase secondary current fundamental waves phase angle difference
When, it is transformer external area error electric current or and echo surge current；
11st step, when B phase phase spill currentsThe spill current that amplitude is more than or equal to tranformer protection starts setting valve Δ
During I, the high-pressure side B phase secondary current areas S of calculating transformerY high-pressure sides BWith the medium voltage side B phase secondary current areas of transformer
SY medium voltage sides BPoor Δ Sb, high-pressure side B phase secondary currents are used during calculatingMedium voltage side B phase secondary currents
High-pressure side B phase secondary current areas SY high-pressure sides BWith the medium voltage side B phase secondary current areas S of transformerY medium voltage sides BCalculating
Method and the 8th step high-pressure side A phase secondary current areas SY high-pressure sides AWith medium voltage side A phase secondary current areas SY medium voltage sides AComputational methods
It is identical, high-pressure side B phase secondary current areas SY high-pressure sides BWith medium voltage side B phase secondary current areas SY medium voltage sides BDifference in areas be Δ Sb；
12nd step, when B phase phase spill currentsThe spill current that amplitude is more than or equal to tranformer protection starts setting valve Δ
During I, while calculating high-pressure side B phases secondary current fundamental wave phase angle and medium voltage side B phase secondary current fundamental wave phase angles, to be used during calculating
High-pressure side B phase secondary currents after 4th successive stepMedium voltage side B phase secondary currents
13rd step, as high-pressure side B phase secondary current areas SY high-pressure sides BWith medium voltage side B phase secondary current areas SY medium voltage sides B's
Difference in areas Δ SbMore than or equal to B phase secondary current difference in areas setting valves SB, also, high-pressure side B phases secondary current fundamental wave phase angle is with
It is transformer troubles inside the sample space electric current when pressing side B phase secondary current fundamental waves phase angle difference more than 90 degree；When high-pressure side B phase secondary currents
Area SY high-pressure sides BWith medium voltage side B phase secondary current areas SY medium voltage sides BDifference in areas Δ SbIt is whole more than or equal to B phase secondary current difference in areas
Definite value SB, also, high-pressure side B phases secondary current fundamental wave phase angle is less than or equal to 90 with medium voltage side B phase secondary current fundamental waves phase angle difference
It is transformer external area error electric current or and echo surge current when spending；
14th step, when C phase phase spill currentsThe spill current that amplitude is more than or equal to tranformer protection starts setting valve Δ
During I, the high-pressure side C phase secondary current areas S of calculating transformerY high-pressure sides CWith the medium voltage side C phase secondary current areas of transformer
SY medium voltage sides CPoor Δ Sc, high-pressure side C phase secondary currents are used during calculatingMedium voltage side C phase secondary currents
High-pressure side C phase secondary current areas SY high-pressure sides CWith the medium voltage side C phase secondary current areas S of transformerY medium voltage sides CCalculating
Method and the 8th step high-pressure side secondary current area SY high-pressure sides AWith medium voltage side A phase secondary current areas SY medium voltage sides AComputational methods phase
Together, high-pressure side C phases secondary current area SY high-pressure sides CWith medium voltage side C phase secondary current areas SY medium voltage sides CDifference in areas be Δ Sc；
15th step, when C phase phase spill currentsThe spill current that amplitude is more than or equal to tranformer protection starts setting valve Δ I
When, while calculating high-pressure side C phases secondary current fundamental wave phase angle and medium voltage side C phase secondary current fundamental wave phase angles, to be used during calculating
High-pressure side C phase secondary currents after 4th successive stepMedium voltage side C phase secondary currents
16th step, as high-pressure side C phase secondary current areas SY high-pressure sides CWith medium voltage side C phase secondary current areas SY medium voltage sides C's
Difference in areas Δ ScMore than or equal to C phase secondary current difference in areas setting valves SC, also, high-pressure side C phases secondary current fundamental wave phase angle is with
It is transformer troubles inside the sample space electric current when pressing side C phase secondary current fundamental waves phase angle difference more than 90 degree；When high-pressure side C phase secondary currents
Area SY high-pressure sides CWith medium voltage side C phase secondary current areas SY medium voltage sides CDifference in areas Δ ScIt is whole more than or equal to C phase secondary current difference in areas
Definite value SC, also, high-pressure side C phases secondary current fundamental wave phase angle is less than or equal to 90 with medium voltage side C phase secondary current fundamental waves phase angle difference
It is transformer external area error electric current or and echo surge current when spending.
The present invention can accurately differentiate transformer fault electric current with and echo surge current, it is to avoid the malfunction of transformer differential protection
Make, it is ensured that the normal operation of grid master.
Brief description of the drawings
Fig. 1 is each electric current positive direction schematic diagram of side first and second of transformer of invention.
Embodiment
The present invention is described in detail below in conjunction with the accompanying drawings：
The discrimination method of a kind of in tranformer protection and echo surge current and fault current, comprises the following steps：
The high-pressure side secondary current sampled value of the first step, the transformer of acquisition Y-Y- Δ wiring patterns, obtains Y-Y- Δs and connects
The medium voltage side secondary current sampled value of the transformer of line style formula, obtains the secondary electricity of low-pressure side of the transformer of Y-Y- Δ wiring patterns
Flow sampled value；
It is second step, the high-pressure side secondary current sampled value, medium voltage side secondary current sampled value and low-pressure side of acquisition is secondary
Current sampling data, carries out differential filtering respectively；
3rd step, by the high-pressure side secondary current sampled value after differential filtering, the medium voltage side secondary current after differential filtering
Low-pressure side secondary current sampled value after sampled value and differential filtering, carries out all-wave Fourier digital filtering, obtains transformation respectively
Device high-pressure side secondary current fundamental voltage amplitude and phase angle, transformer medium voltage side secondary current fundamental voltage amplitude and phase angle, transformer low voltage
Side secondary current fundamental voltage amplitude and phase angle；
The computational methods of high-pressure side secondary current fundamental voltage amplitude and phase angle are：
Sampling number of the high voltage side of transformer secondary current per cycle is first set as N, then high voltage side of transformer secondary current
The current sampling data of sampled point is i (k), k=0,1, and 2 ... N-1, the sampling interval is Δ t；
According to following Fourier transform formula：
Wherein：
The angular frequency of ω-high voltage side of transformer secondary current cycle；
After the sinusoidal coefficients for obtaining fundamental wave, then the plural form of fundametal compoment is：
High-pressure side secondary current fundamental voltage amplitude is：
High-pressure side secondary current fundamental wave phase angle is：
Using above same method, transformer medium voltage side secondary current fundamental voltage amplitude and phase angle, and transformer are calculated
Low-pressure side secondary current fundamental voltage amplitude and phase angle；
4th step, utilize Y- Δ transform methods, adjustment each side current amplitude of transformer and phase angle；By Y-Y- Δ wiring patterns
The high-pressure side secondary current of Y connections of transformer be converted to the high-pressure side secondary current of Δ connection, by Y-Y- Δ wiring patterns
The medium voltage side secondary current of Y connections of transformer be converted to the medium voltage side secondary current of Δ connection, Y-Y- Δ wiring patterns
The low-pressure side secondary current of the Δ connection of transformer is constant；By transformer medium voltage side current amplitude according to transformer voltage ratio convert to
High voltage side of transformer, step down side current amplitude is converted to high voltage side of transformer according to transformer voltage ratio；Thus obtain
After filtering and conversion：High-pressure side A phase secondary currentsHigh-pressure side B phase secondary currentsHigh-pressure side C phase secondary currentsMedium voltage side A phase secondary currentsMedium voltage side B phase secondary currentsMedium voltage side C phase secondary currentsLow-pressure side A phases
Secondary currentLow-pressure side B phase secondary currentsLow-pressure side C phase secondary currents
5th step, the spill current for the tranformer protection for obtaining Y-Y- Δ wiring patterns start setting valve Δ I；6th step, meter
Calculate A phase phase spill currentsB phase phase spill currentsWith C phase phase spill currentsCalculation formula is as follows：
7th step, obtain respectively：The medium voltage side A phases of the high-pressure side A phase secondary current areas and transformer of transformer are secondary
The A phase secondary current difference in areas setting valves S of current areas differenceA；The high-pressure side B phase secondary current areas of transformer and transformer
The B phase secondary current difference in areas setting valves S of medium voltage side B phase secondary current difference in areasB；The high-pressure side C phase secondary currents of transformer
Area and the C phase secondary current difference in areas setting valves S of the medium voltage side C phase secondary current difference in areas of transformerC；8th step, when A phases
Phase spill currentWhen the spill current that amplitude is more than or equal to tranformer protection starts setting valve Δ I, the high-pressure side of calculating transformer
A phase secondary current areas SY high-pressure sides AWith the medium voltage side A phase secondary current areas S of transformerY medium voltage sides APoor Δ Sa, to be used during calculating
High-pressure side A phase secondary currentsMedium voltage side A phase secondary currents
High-pressure side secondary current area SY high-pressure sides AComputational methods be：
Sampling number of the high voltage side of transformer electric current per cycle is first set as N, the electricity of high voltage side of transformer current sample point
Sampled value i (k) is flowed, k=0,1,2 ... N-1, the sampling interval are Δ t, using Rectangular Method, between calculating between two sampled points
Every area, calculation formula is as follows：
ΔS0=i (0) * Δs t；
ΔS1=i (1) * Δs t；
ΔS2=i (2) * Δs t；
……；
ΔSN-1=i (N-1) * Δs t；
The sampled point for obtaining the spill current startup setting valve Δ I moment that phase spill current is more than or equal to tranformer protection is x；
Then y moment high voltage side of transformer A phase secondary current areas：
Medium voltage side A phase secondary current areas SY medium voltage sides AComputational methods be：
Sampling number of the transformer medium voltage side electric current per cycle is first set as N, the electricity of transformer medium voltage side current sample point
Sampled value i (k) is flowed, k=0,1,2 ... N-1, the sampling interval are Δ t, using Rectangular Method, between calculating between two sampled points
Every area, calculation formula is as follows：
ΔS0=i (0) * Δs t；
ΔS1=i (1) * Δs t；
ΔS2=i (2) * Δs t；
……；
ΔSN-1=i (N-1) * Δs t；
The sampled point for obtaining the spill current startup setting valve Δ I moment that phase spill current is more than or equal to tranformer protection is x；
Then y moment transformers medium voltage side A phase secondary current areas：
High-pressure side A phase secondary current areas SY high-pressure sides AWith medium voltage side A phase secondary current areas SY medium voltage sides ADifference in areas be Δ Sa；
9th step, when A phase phase spill currentsWhen the spill current that amplitude is more than or equal to transformer starts setting valve Δ I, together
When calculate high-pressure side A phases secondary current fundamental wave phase angle and medium voltage side A phase secondary current fundamental wave phase angles, the 4th step is used during calculating
High-pressure side A phase secondary currents after adjustmentMedium voltage side A phase secondary currents
Tenth step, as high-pressure side A phase secondary current areas SY high-pressure sides AWith medium voltage side A phase secondary current areas SY medium voltage sides AFace
Product moment Δ SaMore than or equal to A phase secondary current difference in areas setting valves SA, also, high-pressure side A phases secondary current fundamental wave phase angle and middle pressure
It is transformer troubles inside the sample space electric current when side A phase secondary current fundamental waves phase angle difference is more than 90 degree；When high-pressure side A phase secondary currents face
Product SY high-pressure sides AWith medium voltage side A phase secondary current areas SY medium voltage sides ADifference in areas Δ SaAdjusted more than or equal to A phase secondary current difference in areas
Value SA, also, high-pressure side A phases secondary current fundamental wave phase angle is less than or equal to 90 degree with medium voltage side A phase secondary current fundamental waves phase angle difference
When, it is transformer external area error electric current or and echo surge current；
11st step, when B phase phase spill currentsThe spill current that amplitude is more than or equal to tranformer protection starts setting valve Δ
During I, the high-pressure side B phase secondary current areas S of calculating transformerY high-pressure sides BWith the medium voltage side B phase secondary current areas of transformer
SY medium voltage sides BPoor Δ Sb, high-pressure side B phase secondary currents are used during calculatingMedium voltage side B phase secondary currents
High-pressure side B phase secondary current areas SY high-pressure sides BWith the medium voltage side B phase secondary current areas S of transformerY medium voltage sides BCalculating
Method and the 8th step high-pressure side A phase secondary current areas SY high-pressure sides AWith medium voltage side A phase secondary current areas SY medium voltage sides AComputational methods
It is identical, high-pressure side B phase secondary current areas SY high-pressure sides BWith medium voltage side B phase secondary current areas SY medium voltage sides BDifference in areas be Δ Sb；
12nd step, when B phase phase spill currentsThe spill current that amplitude is more than or equal to tranformer protection starts setting valve Δ
During I, while calculating high-pressure side B phases secondary current fundamental wave phase angle and medium voltage side B phase secondary current fundamental wave phase angles, to be used during calculating
High-pressure side B phase secondary currents after 4th successive stepMedium voltage side B phase secondary currents
13rd step, as high-pressure side B phase secondary current areas SY high-pressure sides BWith medium voltage side B phase secondary current areas SY medium voltage sides B's
Difference in areas Δ SbMore than or equal to B phase secondary current difference in areas setting valves SB, also, high-pressure side B phases secondary current fundamental wave phase angle is with
It is transformer troubles inside the sample space electric current when pressing side B phase secondary current fundamental waves phase angle difference more than 90 degree；When high-pressure side B phase secondary currents
Area SY high-pressure sides BWith medium voltage side B phase secondary current areas SY medium voltage sides BDifference in areas Δ SbIt is whole more than or equal to B phase secondary current difference in areas
Definite value SB, also, high-pressure side B phases secondary current fundamental wave phase angle is less than or equal to 90 with medium voltage side B phase secondary current fundamental waves phase angle difference
It is transformer external area error electric current or and echo surge current when spending；
14th step, when C phase phase spill currentsThe spill current that amplitude is more than or equal to tranformer protection starts setting valve Δ
During I, the high-pressure side C phase secondary current areas S of calculating transformerY high-pressure sides CWith the medium voltage side C phase secondary current areas of transformer
SY medium voltage sides CPoor Δ Sc, high-pressure side C phase secondary currents are used during calculatingMedium voltage side C phase secondary currents
High-pressure side C phase secondary current areas SY high-pressure sides CWith the medium voltage side C phase secondary current areas S of transformerY medium voltage sides CCalculating
Method and the 8th step high-pressure side secondary current area SY high-pressure sides AWith medium voltage side A phase secondary current areas SY medium voltage sides AComputational methods phase
Together, high-pressure side C phases secondary current area SY high-pressure sides CWith medium voltage side C phase secondary current areas SY medium voltage sides CDifference in areas be Δ Sc；
15th step, when C phase phase spill currentsThe spill current that amplitude is more than or equal to tranformer protection starts setting valve Δ
During I, while calculating high-pressure side C phases secondary current fundamental wave phase angle and medium voltage side C phase secondary current fundamental wave phase angles, to be used during calculating
High-pressure side C phase secondary currents after 4th successive stepMedium voltage side C phase secondary currents
16th step, as high-pressure side C phase secondary current areas SY high-pressure sides CWith medium voltage side C phase secondary current areas SY medium voltage sides C's
Difference in areas Δ ScMore than or equal to C phase secondary current difference in areas setting valves SC, also, high-pressure side C phases secondary current fundamental wave phase angle is with
It is transformer troubles inside the sample space electric current when pressing side C phase secondary current fundamental waves phase angle difference more than 90 degree；When high-pressure side C phase secondary currents
Area SY high-pressure sides CWith medium voltage side C phase secondary current areas SY medium voltage sides CDifference in areas Δ ScIt is whole more than or equal to C phase secondary current difference in areas
Definite value SC, also, high-pressure side C phases secondary current fundamental wave phase angle is less than or equal to 90 with medium voltage side C phase secondary current fundamental waves phase angle difference
It is transformer external area error electric current or and echo surge current when spending.
During for transformer medium voltage side or low-pressure side non-transformer, using the side of transformer three composite voltage (low-voltage and
Negative sequence voltage) constitute or high-pressure side secondary current phase angle and middle pressure in the step of logic de the tenth, the 13rd step and the 16th step
The condition of side secondary current phase angle difference；It can so avoid occurring tripping in troubles inside the sample space；
Low-voltage and the computational methods of negative sequence voltage are：
Fundamental voltage filters out fundamental voltage using the all-wave Fourier digital filtering of the 3rd step；
Positive and negative sequence voltage computational methods are：
Wherein：A=ej120°For the vector calculus factor；
When transformer medium voltage side non-transformer, composite voltage (low-voltage and negative sequence voltage) unlocking can be passed through, now
Only need Cutoff current difference in areas to exceed setting valve, no longer differentiate high pressure side current angle, protection device is exportable tripping operation letter
Number, each side breaker of tripping transformer.There are power conditions for step down side, can equally draw above-mentioned conclusion, but this
When angle to be determined as high and low pressure side current angle poor.
The electric current for becoming transformer Y sides of changing commanders using Y- Δs is converted to Δ；Δ side is constant, adjusts each side current amplitude of transformer
And phase, then calculate spill current；For the transformer of the wiring patterns of Y-Y- Δs -11, its current transformation formula such as following table：
Spill current is calculated using following formula：
In formula：- it is A, B, C phase spill current；
- it is high voltage side of transformer A, B, C phase current before conversion；
- it is transformer medium voltage side A, B, C phase current before conversion；
- it is high voltage side of transformer A, B, C phase current after conversion；
- it is transformer medium voltage side A, B, C phase current after conversion；
- it is step down side A, B, C phase current；
The transformer of other wiring groups can equally derive its transformation for mula according to each side phase condition of transformer.
SA、SBAnd SCSetting valve according to transformer access system situation calculate after adjusted；
Adjusting for Δ I is adjusted with reference to current transformer differential protection setting principle.
Claims (1)
1. the discrimination method of a kind of in tranformer protection and echo surge current and fault current, comprises the following steps：
The high-pressure side secondary current sampled value of the first step, the transformer of acquisition Y-Y- Δ wiring patterns, obtains Y-Y- Δ patch types
The medium voltage side secondary current sampled value of the transformer of formula, the low-pressure side secondary current for obtaining the transformer of Y-Y- Δ wiring patterns is adopted
Sample value；
Second step, high-pressure side secondary current sampled value, medium voltage side secondary current sampled value and low-pressure side secondary current by acquisition
Sampled value, carries out differential filtering respectively；
3rd step, by the high-pressure side secondary current sampled value after differential filtering, the medium voltage side secondary current after differential filtering sample
Low-pressure side secondary current sampled value after value and differential filtering, carries out all-wave Fourier digital filtering respectively, obtains transformer high
Press side secondary current fundamental voltage amplitude and phase angle, transformer medium voltage side secondary current fundamental voltage amplitude and phase angle, step down side two
Primary current fundamental voltage amplitude and phase angle；
The computational methods of high-pressure side secondary current fundamental voltage amplitude and phase angle are：
Sampling number of the high voltage side of transformer secondary current per cycle is first set as N, then high voltage side of transformer secondary current is sampled
The current sampling data of point is i (k), k=0,1, and 2 ... N-1, the sampling interval is Δ t；
According to following Fourier transform formula：
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<mo>(</mo>
<mi>k</mi>
<mo>)</mo>
</mrow>
<mo>&CenterDot;</mo>
<mi>c</mi>
<mi>o</mi>
<mi>s</mi>
<mrow>
<mo>(</mo>
<mi>&omega;</mi>
<mi>k</mi>
<mo>&CenterDot;</mo>
<mi>&Delta;</mi>
<mi>t</mi>
<mo>)</mo>
</mrow>
<mo>;</mo>
</mrow>
Wherein：
The angular frequency of ω-high voltage side of transformer secondary current cycle；
After the sinusoidal coefficients for obtaining fundamental wave, then the plural form of fundametal compoment is：
<mrow>
<msub>
<mover>
<mi>I</mi>
<mo>&CenterDot;</mo>
</mover>
<mn>1</mn>
</msub>
<mo>=</mo>
<mfrac>
<mn>1</mn>
<msqrt>
<mn>2</mn>
</msqrt>
</mfrac>
<mrow>
<mo>(</mo>
<msub>
<mi>I</mi>
<mrow>
<mn>1</mn>
<mi>s</mi>
</mrow>
</msub>
<mo>+</mo>
<msub>
<mi>jI</mi>
<mrow>
<mn>1</mn>
<mi>c</mi>
</mrow>
</msub>
<mo>)</mo>
</mrow>
<mo>;</mo>
</mrow>
High-pressure side secondary current fundamental voltage amplitude is：
<mrow>
<msub>
<mi>I</mi>
<mn>1</mn>
</msub>
<mo>=</mo>
<mfrac>
<mn>1</mn>
<msqrt>
<mn>2</mn>
</msqrt>
</mfrac>
<msqrt>
<mrow>
<msubsup>
<mi>I</mi>
<mrow>
<mn>1</mn>
<mi>s</mi>
</mrow>
<mn>2</mn>
</msubsup>
<mo>+</mo>
<msubsup>
<mi>I</mi>
<mrow>
<mn>1</mn>
<mi>c</mi>
</mrow>
<mn>2</mn>
</msubsup>
</mrow>
</msqrt>
<mo>;</mo>
</mrow>
High-pressure side secondary current fundamental wave phase angle is：
<mrow>
<mi>&theta;</mi>
<mo>=</mo>
<mi>a</mi>
<mi>r</mi>
<mi>c</mi>
<mi>t</mi>
<mi>g</mi>
<mfrac>
<msub>
<mi>I</mi>
<mrow>
<mn>1</mn>
<mi>c</mi>
</mrow>
</msub>
<msub>
<mi>I</mi>
<mrow>
<mn>1</mn>
<mi>s</mi>
</mrow>
</msub>
</mfrac>
<mo>;</mo>
</mrow>
Using above same method, transformer medium voltage side secondary current fundamental voltage amplitude and phase angle, and transformer low voltage are calculated
Side secondary current fundamental voltage amplitude and phase angle；
4th step, utilize Y- Δ transform methods, adjustment each side current amplitude of transformer and phase angle；By the change of Y-Y- Δ wiring patterns
The high-pressure side secondary current of the Y connections of depressor is converted to the high-pressure side secondary current of Δ connection, by the change of Y-Y- Δ wiring patterns
The medium voltage side secondary current of the Y connections of depressor is converted to the medium voltage side secondary current of Δ connection, the transformation of Y-Y- Δ wiring patterns
The low-pressure side secondary current of the Δ connection of device is constant；Transformer medium voltage side current amplitude is converted to transformation according to transformer voltage ratio
Device high-pressure side, step down side current amplitude is converted to high voltage side of transformer according to transformer voltage ratio；Thus filtered
And after conversion：High-pressure side A phase secondary currentsHigh-pressure side B phase secondary currentsHigh-pressure side C phase secondary currentsIn
Press side A phase secondary currentsMedium voltage side B phase secondary currentsMedium voltage side C phase secondary currentsThe secondary electricity of low-pressure side A phases
StreamLow-pressure side B phase secondary currentsLow-pressure side C phase secondary currents
5th step, the spill current for the tranformer protection for obtaining Y-Y- Δ wiring patterns start setting valve Δ I；
6th step, calculating A phase phase spill currentsB phase phase spill currentsWith C phase phase spill currentsCalculation formula is as follows：
<mrow>
<msub>
<mover>
<mi>I</mi>
<mo>&CenterDot;</mo>
</mover>
<mrow>
<mi>c</mi>
<mi>l</mi>
<mi>a</mi>
</mrow>
</msub>
<mo>=</mo>
<msub>
<mover>
<mi>I</mi>
<mo>&CenterDot;</mo>
</mover>
<mrow>
<mn>1</mn>
<mi>A</mi>
</mrow>
</msub>
<mo>-</mo>
<msub>
<mover>
<mi>I</mi>
<mo>&CenterDot;</mo>
</mover>
<mrow>
<mn>2</mn>
<mi>A</mi>
</mrow>
</msub>
<mo>-</mo>
<msub>
<mover>
<mi>I</mi>
<mo>&CenterDot;</mo>
</mover>
<mrow>
<mn>3</mn>
<mi>A</mi>
</mrow>
</msub>
<mo>;</mo>
</mrow>
<mrow>
<msub>
<mover>
<mi>I</mi>
<mo>&CenterDot;</mo>
</mover>
<mrow>
<mi>c</mi>
<mi>l</mi>
<mi>b</mi>
</mrow>
</msub>
<mo>=</mo>
<msub>
<mover>
<mi>I</mi>
<mo>&CenterDot;</mo>
</mover>
<mrow>
<mn>1</mn>
<mi>B</mi>
</mrow>
</msub>
<mo>-</mo>
<msub>
<mover>
<mi>I</mi>
<mo>&CenterDot;</mo>
</mover>
<mrow>
<mn>2</mn>
<mi>B</mi>
</mrow>
</msub>
<mo>-</mo>
<msub>
<mover>
<mi>I</mi>
<mo>&CenterDot;</mo>
</mover>
<mrow>
<mn>3</mn>
<mi>B</mi>
</mrow>
</msub>
<mo>;</mo>
</mrow>
<mrow>
<msub>
<mover>
<mi>I</mi>
<mo>&CenterDot;</mo>
</mover>
<mrow>
<mi>c</mi>
<mi>l</mi>
<mi>c</mi>
</mrow>
</msub>
<mo>=</mo>
<msub>
<mover>
<mi>I</mi>
<mo>&CenterDot;</mo>
</mover>
<mrow>
<mn>1</mn>
<mi>C</mi>
</mrow>
</msub>
<mo>-</mo>
<msub>
<mover>
<mi>I</mi>
<mo>&CenterDot;</mo>
</mover>
<mrow>
<mn>2</mn>
<mi>C</mi>
</mrow>
</msub>
<mo>-</mo>
<msub>
<mover>
<mi>I</mi>
<mo>&CenterDot;</mo>
</mover>
<mrow>
<mn>3</mn>
<mi>C</mi>
</mrow>
</msub>
<mo>;</mo>
</mrow>
7th step, obtain respectively：The high-pressure side A phase secondary current areas of transformer and the medium voltage side A phase secondary currents of transformer
The A phase secondary current difference in areas setting valves S of difference in areasA；The high-pressure side B phase secondary current areas and the middle pressure of transformer of transformer
The B phase secondary current difference in areas setting valves S of side B phase secondary current difference in areasB；The high-pressure side C phase secondary current areas of transformer
With the C phase secondary current difference in areas setting valves S of the medium voltage side C phase secondary current difference in areas of transformerC；
8th step, when A phase phase spill currentsWhen the spill current that amplitude is more than or equal to tranformer protection starts setting valve Δ I, meter
Calculate the high-pressure side A phase secondary current areas S of transformerY high-pressure sides AWith the medium voltage side A phase secondary current areas S of transformerY medium voltage sides ADifference
ΔSa, high-pressure side A phase secondary currents are used during calculatingMedium voltage side A phase secondary currents
High-pressure side secondary current area SY high-pressure sides AComputational methods be：
Sampling number of the high voltage side of transformer electric current per cycle is first set as N, the electric current of high voltage side of transformer current sample point is adopted
Sample value i (k), k=0,1,2 ... N-1, the sampling interval is Δ t, using Rectangular Method, calculates the septal surface between two sampled points
Product, calculation formula is as follows：
ΔS0=i (0) * Δs t；
ΔS1=i (1) * Δs t；
ΔS2=i (2) * Δs t；
……；
ΔSN-1=i (N-1) * Δs t；
The sampled point for obtaining the spill current startup setting valve Δ I moment that phase spill current is more than or equal to tranformer protection is x；
Then y moment high voltage side of transformer A phase secondary current areas：
Medium voltage side A phase secondary current areas SY medium voltage sides AComputational methods be：
Sampling number of the transformer medium voltage side electric current per cycle is first set as N, the electric current of transformer medium voltage side current sample point is adopted
Sample value i (k), k=0,1,2 ... N-1, the sampling interval is Δ t, using Rectangular Method, calculates the septal surface between two sampled points
Product, calculation formula is as follows：
ΔS0=i (0) * Δs t；
ΔS1=i (1) * Δs t；
ΔS2=i (2) * Δs t；
……；
ΔSN-1=i (N-1) * Δs t；
The sampled point for obtaining the spill current startup setting valve Δ I moment that phase spill current is more than or equal to tranformer protection is x；
Then y moment transformers medium voltage side A phase secondary current areas：
High-pressure side A phase secondary current areas SY high-pressure sides AWith medium voltage side A phase secondary current areas SY medium voltage sides ADifference in areas be Δ Sa；
9th step, when A phase phase spill currentsWhen the spill current that amplitude is more than or equal to transformer starts setting valve Δ I, count simultaneously
High-pressure side A phases secondary current fundamental wave phase angle and medium voltage side A phase secondary current fundamental wave phase angles are calculated, the 4th successive step is used during calculating
High-pressure side A phase secondary currents afterwardsMedium voltage side A phase secondary currents
Tenth step, as high-pressure side A phase secondary current areas SY high-pressure sides AWith medium voltage side A phase secondary current areas SY medium voltage sides ADifference in areas Δ
SaMore than or equal to A phase secondary current difference in areas setting valves SA, also, high-pressure side A phases secondary current fundamental wave phase angle and medium voltage side A phases
It is transformer troubles inside the sample space electric current when secondary current fundamental wave phase angle difference is more than 90 degree；When high-pressure side A phase secondary current areas
SY high-pressure sides AWith medium voltage side A phase secondary current areas SY medium voltage sides ADifference in areas Δ SaMore than or equal to A phase secondary current difference in areas setting valves
SA, also, high-pressure side A phases secondary current fundamental wave phase angle and medium voltage side A phase secondary current fundamental waves phase angle difference are when being less than or equal to 90 degree,
For transformer external area error electric current or and echo surge current；
11st step, when B phase phase spill currentsWhen the spill current that amplitude is more than or equal to tranformer protection starts setting valve Δ I,
The high-pressure side B phase secondary current areas S of calculating transformerY high-pressure sides BWith the medium voltage side B phase secondary current areas S of transformerY medium voltage sides B's
Poor Δ Sb, high-pressure side B phase secondary currents are used during calculatingMedium voltage side B phase secondary currents
High-pressure side B phase secondary current areas SY high-pressure sides BWith the medium voltage side B phase secondary current areas S of transformerY medium voltage sides BComputational methods
With the 8th step high-pressure side A phase secondary current areas SY high-pressure sides AWith medium voltage side A phase secondary current areas SY medium voltage sides AComputational methods phase
Together, high-pressure side B phases secondary current area SY high-pressure sides BWith medium voltage side B phase secondary current areas SY medium voltage sides BDifference in areas be Δ Sb；
12nd step, when B phase phase spill currentsWhen the spill current that amplitude is more than or equal to tranformer protection starts setting valve Δ I,
High-pressure side B phases secondary current fundamental wave phase angle and medium voltage side B phase secondary current fundamental wave phase angles are calculated simultaneously, and the 4th is used during calculating
High-pressure side B phase secondary currents after successive stepMedium voltage side B phase secondary currents
13rd step, as high-pressure side B phase secondary current areas SY high-pressure sides BWith medium voltage side B phase secondary current areas SY medium voltage sides BDifference in areas
ΔSbMore than or equal to B phase secondary current difference in areas setting valves SB, also, high-pressure side B phases secondary current fundamental wave phase angle and medium voltage side B
It is transformer troubles inside the sample space electric current when phase secondary current fundamental wave phase angle difference is more than 90 degree；When high-pressure side B phase secondary current areas
SY high-pressure sides BWith medium voltage side B phase secondary current areas SY medium voltage sides BDifference in areas Δ SbMore than or equal to B phase secondary current difference in areas setting valves
SB, also, high-pressure side B phases secondary current fundamental wave phase angle and medium voltage side B phase secondary current fundamental waves phase angle difference are when being less than or equal to 90 degree,
For transformer external area error electric current or and echo surge current；
14th step, when C phase phase spill currentsWhen the spill current that amplitude is more than or equal to tranformer protection starts setting valve Δ I,
The high-pressure side C phase secondary current areas S of calculating transformerY high-pressure sides CWith the medium voltage side C phase secondary current areas S of transformerY medium voltage sides C's
Poor Δ Sc, high-pressure side C phase secondary currents are used during calculatingMedium voltage side C phase secondary currents
High-pressure side C phase secondary current areas SY high-pressure sides CWith the medium voltage side C phase secondary current areas S of transformerY medium voltage sides CComputational methods
With the 8th step high-pressure side secondary current area SY high-pressure sides AWith medium voltage side A phase secondary current areas SY medium voltage sides AComputational methods it is identical, it is high
Press side C phase secondary current areas SY high-pressure sides CWith medium voltage side C phase secondary current areas SY medium voltage sides CDifference in areas be Δ Sc；
15th step, when C phase phase spill currentsWhen the spill current that amplitude is more than or equal to tranformer protection starts setting valve Δ I,
High-pressure side C phases secondary current fundamental wave phase angle and medium voltage side C phase secondary current fundamental wave phase angles are calculated simultaneously, and the 4th is used during calculating
High-pressure side C phase secondary currents after successive stepMedium voltage side C phase secondary currents
16th step, as high-pressure side C phase secondary current areas SY high-pressure sides CWith medium voltage side C phase secondary current areas SY medium voltage sides CDifference in areas
ΔScMore than or equal to C phase secondary current difference in areas setting valves SC, also, high-pressure side C phases secondary current fundamental wave phase angle and medium voltage side C
It is transformer troubles inside the sample space electric current when phase secondary current fundamental wave phase angle difference is more than 90 degree；When high-pressure side C phase secondary current areas
SY high-pressure sides CWith medium voltage side C phase secondary current areas SY medium voltage sides CDifference in areas Δ ScMore than or equal to C phase secondary current difference in areas setting valves
SC, also, high-pressure side C phases secondary current fundamental wave phase angle and medium voltage side C phase secondary current fundamental waves phase angle difference are when being less than or equal to 90 degree,
For transformer external area error electric current or and echo surge current.
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| CN102522726A (en) * | 2011-12-30 | 2012-06-27 | 长园深瑞继保自动化有限公司 | Method for locking magnetizing inrush current of transformer |
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| CN102005726A (en) * | 2010-12-19 | 2011-04-06 | 国网电力科学研究院 | Method for identifying magnetizing inrush current and external fault CT (current transformer) saturation based on waveform discontinuous characteristic |
| EP2544322A1 (en) * | 2011-07-05 | 2013-01-09 | ABB Technology AG | A method of selecting between internal and external faults in parallel lines using one-end measurements |
| CN102522726A (en) * | 2011-12-30 | 2012-06-27 | 长园深瑞继保自动化有限公司 | Method for locking magnetizing inrush current of transformer |
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