CN109884471B - Phasor product active method for judging fault phase and selecting line - Google Patents

Phasor product active method for judging fault phase and selecting line Download PDF

Info

Publication number
CN109884471B
CN109884471B CN201910223581.8A CN201910223581A CN109884471B CN 109884471 B CN109884471 B CN 109884471B CN 201910223581 A CN201910223581 A CN 201910223581A CN 109884471 B CN109884471 B CN 109884471B
Authority
CN
China
Prior art keywords
phasor
phase
fault
voltage
product
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
Application number
CN201910223581.8A
Other languages
Chinese (zh)
Other versions
CN109884471A (en
Inventor
张安斌
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
HEFEI YIXIN ELECTRIC POWER TECHNOLOGY CO LTD
Original Assignee
Individual
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Priority to CN201910223581.8A priority Critical patent/CN109884471B/en
Publication of CN109884471A publication Critical patent/CN109884471A/en
Application granted granted Critical
Publication of CN109884471B publication Critical patent/CN109884471B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Landscapes

  • Emergency Protection Circuit Devices (AREA)

Abstract

The invention discloses a method for judging a fault phase and selecting a line by a phasor product active power method, which provides an average value of half cycle waves of a product obtained by multiplying synchronous sampling values of two phasors by a phasor product active power, and provides a method for judging the phase relation between the phasors according to the magnitude and the positive and negative of the phasor product active power, thereby realizing the judgment and the line selection of the fault phase when a single phase is grounded, avoiding the implementation judgment by accurately calculating each fault quantity and the accurate calculation of the fault quantity such as Fourier transform and the like.

Description

Phasor product active method for judging fault phase and selecting line
Technical Field
The invention relates to a non-effective grounding system of a neutral point of a power grid, in particular to identification and line selection of a fault phase during single-phase grounding fault.
Background
The neutral point ungrounded mode is the most grounded mode adopted by the power distribution network in China all the time, the investment is saved, and the power supply reliability is high. However, when arc grounding occurs in the system, since energy in the earth capacitance cannot be effectively discharged, arc grounding overvoltage or resonance overvoltage will be generated, and the value of the voltage is high, which may threaten the insulation of the electrical equipment in the system.
At present, arc suppression coils and fault phase grounding have defects in arc suppression, a neutral point low-value resistor has to be grounded to quickly cut off a fault line, but the neutral point grounded through the low-value resistor fails when meeting high-fault-point impedance grounding, and the fault line cannot be cut off.
The fault phase grounding arc extinction is simple, the investment is saved, but the fault phase judgment is difficult, the fault phase cannot be accurately judged, the interphase short circuit is caused, the arc extinction cannot be realized, larger accidents are caused, and the condition which the fault phase must have for the fault phase grounding arc extinction is accurately judged.
The single-phase grounding inaccurate line selection is a common fault of all current line selection devices, and the line selection and fault phase judgment cannot be accurately performed because the arc grounding arc is very complicated in the arc extinguishing process, the current line selection and fault phase judgment algorithms start from the accurate calculation of the value of each fault quantity to quantitatively judge faults and line selection, because the arc grounding arc is over uncertain factors in the arc extinguishing process, the arc period is often less than half cycle, the voltages in the arc extinguishing period and the arc period are phase voltage and ground voltage respectively, the voltage parameters are not voltage parameters, Fourier transform and other accurate calculation algorithms are useless, and in addition, the influence of transient quantity, the prior art means are exhaustive, and a satisfactory result cannot be obtained.
Disclosure of Invention
The invention aims to avoid the defects of the prior art, provides a phasor product active method for judging a fault phase and selecting a line, qualitatively judges the fault phase and the line instead of quantitatively, does not depend on accurately calculating the fault phasor for judgment, avoids the influence of various uncertain factors and transient quantities, overcomes the defect of quantitatively judging the fault phase and the line selection at present, does not need to accurately calculate the fault quantity by Fourier transform and the like, realizes hundred percent accurate judgment of the fault phase and the line selection, and ensures the safe operation of a system.
The invention adopts the following technical scheme for solving the technical problems:
the method for judging the fault phase and selecting the line by the phasor product active method has the characteristics that:
phasors
Figure BDA0002004386370000011
Is expressed as uE(t) is: u. ofE(t)＝Ksin(ωt+α)，
Phasors
Figure BDA0002004386370000012
Is expressed as uF(t) is: u. ofF(t)＝Psin(ωt+α+β)，
K and P are phasors
Figure BDA0002004386370000013
And phasor
Figure BDA0002004386370000014
A and a + beta are phasors, respectively
Figure BDA0002004386370000015
And phasor
Figure BDA0002004386370000016
Beta is phasor
Figure BDA0002004386370000017
And phasor
Figure BDA0002004386370000018
The included angle of (A);
phasor
Figure BDA0002004386370000019
And phasor
Figure BDA00020043863700000110
Phasor product of
Figure BDA00020043863700000111
Is marked as
Figure BDA00020043863700000112
Phasor product
Figure BDA00020043863700000113
The phasor product of (A) is recorded as WE*FProduct of phasors
Figure BDA00020043863700000114
The function expression of (a) is denoted as g (t);
WE*F＝KPcosβ
g(t)＝WE*F-KPsin(2ωt+2α+β)
phasor product
Figure BDA0002004386370000021
Phasor of (2) by active power WE*FIs characterized by equation (1.1):
Figure BDA0002004386370000022
uE(ti)、uF(ti) And g (t)i) Are phasors, respectively
Figure BDA0002004386370000023
Phasors
Figure BDA0002004386370000024
Product of sum and phasor
Figure BDA0002004386370000025
Synchronous sample value at time ti, n being phasor
Figure BDA0002004386370000026
And phasor
Figure BDA0002004386370000027
The sampling number of half cycle or integral multiple of half cycle, and n is a natural number not less than 2;
the criterion characterized by equation (1.2) is obtained according to equation (1.1):
Figure BDA0002004386370000028
and calculating phasor product active power according to the formula (1.1), and judging the phase relation between phasors according to the formula (1.2) and the magnitude and the positive and negative of the phasor product active power to realize the judgment and line selection of the fault phase during single-phase grounding.
The phasor product active method for judging the fault phase and selecting the line is also characterized in that:
for a power grid system with m outgoing lines, when a single-phase earth fault occurs in the power grid system,
to be provided with
Figure BDA0002004386370000029
And
Figure BDA00020043863700000210
representing the phase voltages of the leading phase, lagging phase and faulted phase, respectively, and applying the same
Figure BDA00020043863700000211
And
Figure BDA00020043863700000212
defining a set of three-phase symmetrical reference phasors;
to be provided with
Figure BDA00020043863700000213
And
Figure BDA00020043863700000214
respectively representing line voltages of a leading phase relative to a fault phase, a lagging phase relative to a leading phase and a lagging phase relative to a fault phase, and converting the line voltages into the voltage values
Figure BDA00020043863700000215
And
Figure BDA00020043863700000216
defining as another set of three-phase symmetrical reference phasors, dividing said set
Figure BDA00020043863700000217
Defining the reference phasor as a line selection;
to be provided with
Figure BDA00020043863700000218
And
Figure BDA00020043863700000219
respectively representing the voltages relative to the ground of the leading phase, the lagging phase and the fault phase to
Figure BDA00020043863700000220
Represents a neutral point voltage, by
Figure BDA00020043863700000221
And
Figure BDA00020043863700000222
and
Figure BDA00020043863700000223
defining as a fault phasor;
theta represents phasor
Figure BDA00020043863700000224
And phasor
Figure BDA00020043863700000225
The included angle of (A);
to be provided with
Figure BDA00020043863700000226
The capacitance current of the ith outlet is represented, i is 1,2, …, m is a natural number not less than 1, and
Figure BDA00020043863700000227
representing the capacitive current of the faulty line,
Figure BDA00020043863700000228
and
Figure BDA00020043863700000229
the fault phasor has the relation (2.1):
Figure BDA0002004386370000031
constructing a set of three-phase symmetric reference phasors
Figure BDA0002004386370000032
And
Figure BDA0002004386370000033
the three-phase symmetrical reference phasor
Figure BDA0002004386370000034
And
Figure BDA0002004386370000035
leading three-phase voltage
Figure BDA0002004386370000036
And
Figure BDA0002004386370000037
are all in phase
Figure BDA0002004386370000038
Will be provided with
Figure BDA0002004386370000039
The value is randomly selected in the range of (-30 degrees and 60 degrees); or will be
Figure BDA00020043863700000310
Tracking neutral voltage according to equations (2.1) and (2.2)
Figure BDA00020043863700000311
Dynamically take value to
Figure BDA00020043863700000312
And
Figure BDA00020043863700000313
the included angle is acute and minimum;
Figure BDA00020043863700000314
constructing a set of three-phase symmetric reference phasors
Figure BDA00020043863700000315
And
Figure BDA00020043863700000316
the three-phase symmetrical reference phasor
Figure BDA00020043863700000317
And
Figure BDA00020043863700000318
leading three-phase voltage
Figure BDA00020043863700000319
And
Figure BDA00020043863700000320
are all in phase
Figure BDA00020043863700000321
Will be provided with
Figure BDA00020043863700000322
Any value is taken in the range of (-30.5 degrees and 59.5 degrees); or will be
Figure BDA00020043863700000323
Tracking neutral voltage according to equations (2.1) and (2.3)
Figure BDA00020043863700000324
Dynamically take value to
Figure BDA00020043863700000325
And
Figure BDA00020043863700000326
the included angle is acute and minimum;
Figure BDA00020043863700000327
constructing a line selection reference phasor
Figure BDA00020043863700000328
The reference phasor
Figure BDA00020043863700000329
Advance in
Figure BDA00020043863700000330
Phase is
Figure BDA00020043863700000331
Will be provided with
Figure BDA00020043863700000332
The value is randomly selected in the interval of (0 degrees and 90 degrees); or will be
Figure BDA00020043863700000333
Tracking neutral voltage according to equations (2.1) and (2.4)
Figure BDA00020043863700000334
Dynamically take value to
Figure BDA00020043863700000335
And
Figure BDA00020043863700000356
the included angle is acute and minimum;
Figure BDA00020043863700000336
the phasor product for judging a fault phase by a power method is as follows: multiplying the fault phasor by the fault phasor or multiplying the fault phasor by the three-phase symmetrical reference phasor;
the phasor product for realizing the line selection by the power method is as follows: multiplying the capacitance current of each outgoing line by the reference phasor of the selected line, or multiplying the capacitance current of each outgoing line by the voltage of the fault phase-to-ground;
the phasor product active method for judging the fault phase and selecting the line is also characterized in that:
and aiming at the G-phase single-phase earth fault of the system, judging the fault phase according to any criterion as follows:
criterion 1: multiplying the fault phasor by the fault phasor, namely: will be provided with
Figure BDA00020043863700000337
Are respectively connected with
Figure BDA00020043863700000338
And
Figure BDA00020043863700000339
multiply to obtain
Figure BDA00020043863700000355
Figure BDA00020043863700000340
And
Figure BDA00020043863700000341
wherein,
Figure BDA00020043863700000342
the phasor product of (a) is the largest and positive in active power;
criterion 2: multiplying the fault phasor by the three-phase symmetric reference phasor, namely: will be provided with
Figure BDA00020043863700000343
Are respectively connected with
Figure BDA00020043863700000344
And
Figure BDA00020043863700000345
multiply to obtain
Figure BDA00020043863700000346
And
Figure BDA00020043863700000347
wherein,
Figure BDA00020043863700000348
the phasor product of (a) is the largest and positive in active power;
criterion 3: multiplying the fault phasor by the three-phase symmetric reference phasor, namely: will be provided with
Figure BDA00020043863700000349
Are respectively connected with
Figure BDA00020043863700000350
And
Figure BDA00020043863700000351
multiply to obtain
Figure BDA00020043863700000352
And
Figure BDA00020043863700000353
wherein,
Figure BDA00020043863700000354
the phasor product of (a) is the largest and positive in active power;
criterion 4: multiplying the fault phasor by the three-phase symmetric reference phasor, namely:
Figure BDA0002004386370000041
and
Figure BDA0002004386370000042
respectively with the same name
Figure BDA0002004386370000043
Figure BDA0002004386370000044
And
Figure BDA0002004386370000045
multiplying to obtain:
Figure BDA0002004386370000046
and
Figure BDA0002004386370000047
wherein,
Figure BDA0002004386370000048
the phasor product of (a) is the largest and positive in active power;
criterion 5: multiplying the fault phasor by the three-phase symmetric reference phasor, namely: will be provided with
Figure BDA0002004386370000049
And
Figure BDA00020043863700000410
respectively with the same name
Figure BDA00020043863700000411
Figure BDA00020043863700000412
And
Figure BDA00020043863700000413
multiply to obtain
Figure BDA00020043863700000414
And
Figure BDA00020043863700000415
wherein,
Figure BDA00020043863700000416
the phasor product of (a) is the largest and positive in active power;
criterion 6: multiplying the fault phasor by the three-phase symmetric reference phasor, namely: will be provided with
Figure BDA00020043863700000417
Are respectively connected with
Figure BDA00020043863700000418
And
Figure BDA00020043863700000419
multiplying to obtain:
Figure BDA00020043863700000420
and
Figure BDA00020043863700000421
wherein
Figure BDA00020043863700000422
The phasor product of (a) is the largest and positive in active power;
criterion 7: multiplying the fault phasor by the three-phase symmetric reference phasor, namely: will be provided with
Figure BDA00020043863700000423
And
Figure BDA00020043863700000424
respectively with the same name
Figure BDA00020043863700000425
Figure BDA00020043863700000426
And
Figure BDA00020043863700000427
multiplying to obtain:
Figure BDA00020043863700000428
and
Figure BDA00020043863700000429
wherein,
Figure BDA00020043863700000430
the phasor product of (a) is the largest and positive in active power;
the phasor product active method for judging the fault phase and selecting the line is also characterized in that:
and aiming at the G-phase single-phase earth fault of the system, fault line selection is carried out according to any line selection criterion from the following criteria I to the third criterion:
criterion one is as follows: and multiplying the fault phasor by the line selection reference phasor to obtain a phasor product active power, namely: each line to be led out
Figure BDA00020043863700000431
And
Figure BDA00020043863700000432
obtained by multiplication
Figure BDA00020043863700000433
Phasor product active power of fault line
Figure BDA00020043863700000434
Is all that
Figure BDA00020043863700000435
The medium phasor product has the largest active power and is a positive value;
criterion two: and multiplying the fault phasor by the fault phasor and the line selection reference phasor to obtain a phasor product active:
if it is
Figure BDA00020043863700000436
Multiplying the fault phasor by the fault phasor to obtain phasor product active power, each outgoing line
Figure BDA00020043863700000437
And
Figure BDA00020043863700000438
obtained by multiplication
Figure BDA00020043863700000439
Phasor product active power of fault line
Figure BDA00020043863700000440
Is all that
Figure BDA00020043863700000441
The medium phasor product has the largest active power and is a positive value;
if it is
Figure BDA00020043863700000442
And then, multiplying the fault phasor by the line selection reference phasor to obtain a phasor product active power, namely: each line to be led out
Figure BDA00020043863700000443
And
Figure BDA00020043863700000444
obtained by multiplication
Figure BDA00020043863700000445
Phasor product active power of fault line
Figure BDA00020043863700000446
Is all that
Figure BDA00020043863700000447
The medium phasor product has the largest active power and is a positive value;
criterion three: and multiplying the fault phasor by the line selection reference phasor to obtain a phasor product active power, namely: each line to be led out
Figure BDA00020043863700000448
And
Figure BDA00020043863700000449
obtained by multiplication
Figure BDA00020043863700000450
Phasor product active power of fault line
Figure BDA00020043863700000451
Is all that
Figure BDA00020043863700000452
The medium phasor product has the largest active power and is a positive value.
The phasor product active method for judging the fault phase and selecting the line is also characterized in that:
when G-phase single-phase grounding occurs in the system, phase voltage sampling values of three phases are obtained in any mode as follows:
the first method is as follows: leading phase voltage
Figure BDA00020043863700000453
Voltage of lagging phase
Figure BDA00020043863700000454
And fault phase voltage
Figure BDA00020043863700000455
Is equal to the sampling value of the phase-to-ground voltage of the same name phase minus the synchronous sampling value of the neutral point voltage, and is represented by the formula (5.1);
Figure BDA00020043863700000456
the second method comprises the following steps: the method comprises the steps of measuring by using a voltage transformer, sampling the voltage of the secondary side of the voltage transformer to obtain a phase voltage sampling value, and ungrounded a primary side neutral point of the voltage transformer.
The third method comprises the following steps: leading phase voltage
Figure BDA00020043863700000457
Voltage of lagging phase
Figure BDA00020043863700000458
And fault phase voltage
Figure BDA00020043863700000459
The sampled value of (2) is obtained according to an equipotential sampled value of the three-phase ground voltage before the single-phase ground fault, wherein the equipotential sampled value refers to:
sampling is carried out on an alternating current signal f (T) with the period T, and the alternating current signal f (T) when the system normally operates is recorded as f1(t) mixing tτThe AC signal f (t) after the system fault at the moment is recorded as f2(t)，f1(t) after the occurrence of a failure t2Sampling value f of time1(t2) And has the following components:
Figure BDA0002004386370000051
k is a natural number not less than 1, f1(t1) Is f1(t2) Before failure, then:
f1(t2)＝f1(t1) (5.3)
f (t) at t2Fault increment at time:
Δf(t2)＝f2(t2)-f1(t2) (5.4)
f (t) represents the relative voltage of the system, f1(t) represents the phase power of the systemPress and press
Figure BDA0002004386370000052
And
Figure BDA0002004386370000053
with f2(t) represents the relative ground voltage of the system after single-phase grounding
Figure BDA0002004386370000054
And
Figure BDA0002004386370000055
normal operation of the system f (t) ═ f1(t), f (t) f after single-phase grounding2(t)。
The phasor product active method for judging the fault phase and selecting the line is also characterized in that:
line voltage of leading phase to fault phase, lagging phase to leading phase and lagging phase to fault phase
Figure BDA0002004386370000056
And
Figure BDA0002004386370000057
is obtained by any of the following ways:
the first mode is as follows: according to the formula (2.1),
Figure BDA0002004386370000058
and
Figure BDA0002004386370000059
the sampled values are respectively composed of the phase voltages of a leading phase, a lagging phase and a fault phase
Figure BDA00020043863700000510
And
Figure BDA00020043863700000511
subtracting the synchronous sampling values to obtain;
the second mode is as follows: according to the formula (6.1),
Figure BDA00020043863700000512
and
Figure BDA00020043863700000513
the sampling values of the two phases are respectively from the voltages to the ground of the leading phase, the lagging phase and the fault phase
Figure BDA00020043863700000514
And
Figure BDA00020043863700000515
subtracting the synchronous sampling values to obtain;
Figure BDA00020043863700000516
and if the difference between the two phasors is equal to the third phasor, subtracting the synchronous sampling value of the two phasors by the synchronous sampling value of the third phasor, and applying to vector subtraction operation.
The phasor product active method for judging the fault phase and selecting the line is also characterized in that: the sampling value of the neutral point voltage is obtained by adding synchronous sampling values of three phases of voltage to ground according to the formula (2.1) or obtained by converting the sampling value of the open triangular voltage of the voltage transformer;
and if the sum of the two phasors is equal to the third phasor, adding the synchronous sampling values of the two phasors to the synchronous sampling value of the third phasor, and applying to vector addition operation.
The phasor product active method for judging the fault phase and selecting the line is also characterized in that: the line selection criterion is suitable for a power grid system with a neutral point resistor grounded.
The phasor product active method for judging the fault phase and selecting the line is also characterized in that: phasor setting
Figure BDA0002004386370000061
And phasor
Figure BDA0002004386370000062
The phasor product active power of is WE1*F1Phasors
Figure BDA0002004386370000063
And phasor
Figure BDA0002004386370000064
The phasor product active power of is WE2*F2；
If WE1*F1≥WE2*F2Then, there are:
Figure BDA0002004386370000065
or:
Figure BDA0002004386370000066
n1is a number of samples greater than half a cycle time period, uE1(ti)、uF1(ti)、uE2(ti) And uF2(ti) Are respectively as
Figure BDA0002004386370000067
Figure BDA0002004386370000068
And
Figure BDA0002004386370000069
at tiThe sampled value of the moment.
Compared with the prior art, the invention has the beneficial effects that:
1. the device for judging the fault phase and the line selection by the phasor product active power method is originally created, judges the fault phase and the line selection qualitatively rather than quantitatively, does not depend on accurate calculation of each fault quantity to carry out judgment, does not need Fourier transform and other accurate calculation of the fault quantity, thereby abandoning the transient process in which the variable magic measurement is difficult to capture the law, and eliminating the complicated transient data to judge the fault phase and the line selection, thereby realizing the hundred percent of accuracy.
2. The invention provides a phasor product active method, the algorithm is simple and only has arithmetic operation, the average value of the product of two phasor sampling values in half cycle integral multiple time has low requirement on sampling frequency, and the functional requirement of a CPU is low.
3. The invention provides a phasor product active method, wherein the included angle of two phasors is acute angle and positive active power, the included angle is obtuse angle and negative active power, the reference phasor is set according to the phase region in which the fault phasor falls, so that the included angle between the reference phasor and the fault phasor can be kept at an acute angle under any condition, and reliable guarantee is provided for qualitatively judging the fault phasor and selecting a line.
4. The phasor product active fault phase judgment method gives various characteristic criteria, and various criteria verify mutually, so that the accuracy of the phasor product active fault phase judgment method is effectively guaranteed, and the technical problem that the fault phase is difficult to accurately judge is solved.
5. The phasor product active line selection gives three characteristic criteria, and the three criteria are verified mutually, so that the accuracy of line selection of the invention is effectively guaranteed, and the technical problem of line selection is overcome.
6. The invention provides an algorithm of an equipotential sampling value of a phase voltage after a fault, provides a basic condition for selection of a reference phasor, and is suitable for all vectors.
7. The sampling value of the line voltage is obtained by directly subtracting the sampling values of the phase voltages, and a new method is provided for calculating vector sum and difference sampling values.
Drawings
FIG. 1 is a diagram showing the relationship between single-phase earthed phasors;
FIG. 2 is a schematic diagram of the single-phase grounding arc extinguishing time;
reference numbers in the figures:
Figure BDA0002004386370000071
and
Figure BDA0002004386370000072
respectively a leading phase voltage, a lagging phase voltage and a fault phase voltage,
Figure BDA0002004386370000073
Figure BDA0002004386370000074
and
Figure BDA0002004386370000075
leading phase-to-ground voltage, fault phase-to-ground voltage and neutral point voltage, Q, H, G and O are signs of leading phase, lagging phase, fault phase and neutral point, respectively, and theta is fault phase voltage at single-phase grounding
Figure BDA0002004386370000076
To neutral point voltage
Figure BDA0002004386370000077
The angle of,
Figure BDA0002004386370000078
and
Figure BDA0002004386370000079
line voltages of leading, lagging and faulted phases, respectively, ICiIs the capacitance current of the ith outgoing line,
Figure BDA00020043863700000710
is the capacitive current of the faulty line.
Detailed Description
The method for judging the fault phase and selecting the line by the phasor product active method in the embodiment comprises the following steps:
phasors
Figure BDA00020043863700000711
Is expressed as uE(t) is: u. ofE(t) ═ Ksin (ω t + α), phasor
Figure BDA00020043863700000712
Is expressed as uF(t) is: u. ofF(t) ═ Psin (ω t + α + β), K and P are phasors, respectively
Figure BDA00020043863700000713
And phasor
Figure BDA00020043863700000714
A and a + beta are phasors, respectively
Figure BDA00020043863700000715
And phasor
Figure BDA00020043863700000716
Beta is phasor
Figure BDA00020043863700000717
And phasor
Figure BDA00020043863700000718
The included angle of (A);
phasor
Figure BDA00020043863700000719
And phasor
Figure BDA00020043863700000720
Phasor product of
Figure BDA00020043863700000721
Is marked as
Figure BDA00020043863700000722
Phasor product
Figure BDA00020043863700000723
The phasor product of (A) is recorded as WE*FProduct of phasors
Figure BDA00020043863700000724
The function expression of (a) is denoted as g (t);
WE*F＝KPcosβ
g(t)＝WE*F-KPsin(2ωt+2α+β)
phasor product
Figure BDA00020043863700000725
Is a phasor
Figure BDA00020043863700000726
And phasor
Figure BDA00020043863700000727
Is one half of (1), thus phasor
Figure BDA00020043863700000728
And phasor
Figure BDA00020043863700000729
Is the phasor product
Figure BDA00020043863700000730
One cycle, so within half cycle or an integer multiple of half cycle:
Figure BDA00020043863700000731
thus, it is possible to provide
Figure BDA00020043863700000732
Phasor product
Figure BDA00020043863700000733
Phasor of (2) by active power WE*FIs characterized by equation (1.1):
Figure BDA00020043863700000734
uE(ti)、uF(ti) And g (t)i) Are phasors, respectively
Figure BDA00020043863700000735
Phasors
Figure BDA00020043863700000736
Product of sum and phasor
Figure BDA00020043863700000737
At tiSynchronous sampled values of time, n being phasor
Figure BDA00020043863700000738
And phasor
Figure BDA00020043863700000739
The sampling number of half cycle or integral multiple of half cycle, and n is a natural number not less than 2;
the criterion characterized by equation (1.2) is obtained according to equation (1.1):
Figure BDA0002004386370000081
and calculating phasor product active power according to the formula (1.1), and judging the phase relation between phasors according to the formula (1.2) and the magnitude and the positive and negative of the phasor product active power to realize the judgment and line selection of the fault phase during single-phase grounding.
Phasors
Figure BDA0002004386370000082
When the included angle beta is an acute angle, the phasor product is positive when the beta is smaller, and the phasor is positive
Figure BDA0002004386370000083
When the included angle beta is an obtuse angle, the closer beta is to 180 degrees, the more negative the phasor product power is, the larger the absolute value is. In the specific implementation, when the phasor product is used for judging the fault phase and the line selection, phasor is generally adopted
Figure BDA0002004386370000084
The included angle beta is implemented by an acute angle, so that the analysis is simple and convenient.
The invention provides a phasor product active method, the algorithm is simple and only has arithmetic operation, the average value of the product of two phasor sampling values in half cycle integral multiple time has low requirement on sampling frequency, and the functional requirement of a CPU is low.
In specific implementation, for a power grid system with m outgoing lines, when a single-phase ground fault occurs in the power grid system:
to be provided with
Figure BDA0002004386370000085
And
Figure BDA0002004386370000086
respectively representing the phase voltages of the leading phase, lagging phase and faulted phase, and will
Figure BDA0002004386370000087
And
Figure BDA0002004386370000088
defining a set of three-phase symmetrical reference phasors;
to be provided with
Figure BDA0002004386370000089
And
Figure BDA00020043863700000810
line voltages representing leading relative faulted phase, lagging relative leading phase and faulted relative lagging phase, respectively, and will be
Figure BDA00020043863700000811
And
Figure BDA00020043863700000812
defined as another set of three-phase symmetrical reference phasors, will
Figure BDA00020043863700000813
Defining the reference phasor as a line selection;
to be provided with
Figure BDA00020043863700000814
And
Figure BDA00020043863700000815
respectively representing the voltages relative to the ground of the leading phase, the lagging phase and the fault phase to
Figure BDA00020043863700000816
Represents a neutral point voltage of
Figure BDA00020043863700000817
And
Figure BDA00020043863700000818
and
Figure BDA00020043863700000819
defining as a fault phasor;
theta represents phasor
Figure BDA00020043863700000820
And phasor
Figure BDA00020043863700000821
The included angle of (A);
to be provided with
Figure BDA00020043863700000822
The capacitance current of the ith outlet is represented, i is 1,2, …, m is a natural number not less than 1, and
Figure BDA00020043863700000823
representing the capacitive current of the faulty line,
Figure BDA00020043863700000824
and
Figure BDA00020043863700000825
the fault phasor has the relation (2.1):
Figure BDA00020043863700000826
constructing a set of three-phase symmetric reference phasors
Figure BDA00020043863700000827
And
Figure BDA00020043863700000828
three-phase symmetrical reference phasor
Figure BDA00020043863700000829
And
Figure BDA00020043863700000830
leading three-phase voltage
Figure BDA00020043863700000831
And
Figure BDA00020043863700000832
are all in phase
Figure BDA00020043863700000833
Will be provided with
Figure BDA00020043863700000834
The value is randomly selected in the range of (-30 degrees and 60 degrees); or will be
Figure BDA00020043863700000835
Tracking neutral voltage according to equations (2.1) and (2.2)
Figure BDA00020043863700000836
Dynamically take value to
Figure BDA00020043863700000837
And
Figure BDA00020043863700000838
the included angle is acute and minimum;
Figure BDA0002004386370000091
referring to fig. 1, when single-phase grounding occurs, a resistance is connected to the groundThe increase in the reactance, theta, also increases,
Figure BDA0002004386370000092
advance in
Figure BDA0002004386370000093
The phase is then reduced in a manner such that,
Figure BDA0002004386370000094
advance in
Figure BDA0002004386370000095
Phase position
Figure BDA0002004386370000096
Between-30 deg. and 60 deg. and is connected with ground by means of metal,
Figure BDA0002004386370000097
advance in
Figure BDA0002004386370000098
Phase position
Figure BDA0002004386370000099
At 60 deg., when the ground impedance is infinite,
Figure BDA00020043863700000910
advance in
Figure BDA00020043863700000911
Phase position
Figure BDA00020043863700000912
Is-30 deg.
In a particular embodiment of the present invention,
Figure BDA00020043863700000913
any value between-30 degrees and 60 degrees can be selected
Figure BDA00020043863700000914
Has an optimal value of 15 degrees, and the fault point falls on the fault point railAt any point on the trace semicircle,
Figure BDA00020043863700000915
with three-phase symmetrical reference phasors constructed
Figure BDA00020043863700000916
And
Figure BDA00020043863700000917
in (1)
Figure BDA00020043863700000918
The included angles are all less than 45 degrees, which is most beneficial
Figure BDA00020043863700000919
The phasor product of (a) is the largest.
Of course, it is also possible to
Figure BDA00020043863700000920
Tracking neutral voltage
Figure BDA00020043863700000921
The dynamic values, as shown in figure 1,
Figure BDA00020043863700000922
according to equation (2.2), then:
Figure BDA00020043863700000923
advance in
Figure BDA00020043863700000924
Thus, the device is provided with
Figure BDA00020043863700000925
And
Figure BDA00020043863700000926
is acute and close to 0, then,
Figure BDA00020043863700000927
the phasor product of the method is more outstandingAnd the method is more favorable for fault phase judgment.
Constructing a set of three-phase symmetric reference phasors
Figure BDA00020043863700000928
And
Figure BDA00020043863700000929
three-phase symmetrical reference phasor
Figure BDA00020043863700000930
And
Figure BDA00020043863700000931
leading three-phase voltage
Figure BDA00020043863700000932
And
Figure BDA00020043863700000933
are all in phase
Figure BDA00020043863700000934
Will be provided with
Figure BDA00020043863700000935
Any value is taken in the range of (-30.5 degrees and 59.5 degrees); or will be
Figure BDA00020043863700000936
Tracking neutral voltage according to equations (2.1) and (2.3)
Figure BDA00020043863700000937
Dynamically take value to
Figure BDA00020043863700000938
And
Figure BDA00020043863700000939
the included angle is acute and minimum;
referring to fig. 1, in Δ OQJ, there are:
Figure BDA00020043863700000940
Figure BDA00020043863700000941
Figure BDA00020043863700000942
the formula (2.3) is derived from the formulae (2.3.1) to (2.3.3)
Figure BDA00020043863700000943
Calculated from equation (2.3):
Figure BDA00020043863700000944
advance in
Figure BDA00020043863700000945
The phase position is between-3 degrees and 30 degrees,
Figure BDA00020043863700000946
the optimal value of the fault point is 13.5 degrees, the fault point falls on any point on the semicircle of the fault point track,
Figure BDA00020043863700000947
with three-phase symmetrical reference phasors constructed
Figure BDA00020043863700000948
And
Figure BDA00020043863700000949
in (1)
Figure BDA00020043863700000950
The included angles are all less than 16.5 degrees, which is most beneficial
Figure BDA00020043863700000951
The phasor product of (a) is the largest.
Of course, it is also possible to
Figure BDA00020043863700000952
Tracking neutral voltage
Figure BDA00020043863700000953
Dynamically take value to
Figure BDA00020043863700000954
And
Figure BDA00020043863700000955
is acute and close to 0, then,
Figure BDA00020043863700000956
the phasor product of the three-phase current transformer is more outstanding in power, and is more beneficial to fault phase judgment.
Constructing a line selection reference phasor
Figure BDA00020043863700000957
Reference phasor
Figure BDA00020043863700000958
Advance in
Figure BDA00020043863700000959
Phase is
Figure BDA00020043863700000960
Will be provided with
Figure BDA00020043863700000961
The value is randomly selected in the interval of (0 degrees and 90 degrees); or will be
Figure BDA00020043863700000962
Tracking neutral voltage according to equations (2.1) and (2.4)
Figure BDA00020043863700000963
Dynamically take value to
Figure BDA00020043863700000964
And
Figure BDA00020043863700000965
the included angle is acute and minimum;
Figure BDA00020043863700000966
with reference to figure 1 of the drawings,
Figure BDA0002004386370000101
advance in
Figure BDA0002004386370000102
Phase 90-180 DEG, capacitance current of fault line
Figure BDA0002004386370000103
Hysteresis
Figure BDA0002004386370000104
The phase position is 90 degrees,
Figure BDA0002004386370000105
advance in
Figure BDA0002004386370000106
The phase is 0 to 90 degrees,
Figure BDA0002004386370000107
is preferably 45 deg., so that
Figure BDA0002004386370000108
And
Figure BDA0002004386370000109
the included angle of (a) is acute under various grounding conditions,
Figure BDA00020043863700001010
the phasor product of (1) is
Figure BDA00020043863700001011
The active power is the largest and positive.
Of course, it is also possible to
Figure BDA00020043863700001012
Tracking neutral voltage
Figure BDA00020043863700001013
The dynamic value of the numerical control system is taken,
Figure BDA00020043863700001014
so that
Figure BDA00020043863700001015
And
Figure BDA00020043863700001016
is acute and close to 0, then,
Figure BDA00020043863700001017
the phasor product of (1) is
Figure BDA00020043863700001018
The active power is the largest and positive.
The phasor product for judging a fault phase by a power method is as follows: multiplying the fault phasor by the fault phasor or multiplying the fault phasor by the three-phase symmetrical reference phasor;
the phasor product for realizing the line selection by the power method is as follows: multiplying the capacitance current of each outgoing line by the reference phasor of the selected line, or multiplying the capacitance current of each outgoing line by the voltage of the fault phase-to-ground;
if the included angle between the reference phasor and the fault phasor is obtuse, i.e. the direction of the reference phasor is opposite to that of the fault phasor, the phasor product active of the reference phasor and the fault phasor is the most negative.
If the phase A in the system is a fault phase, the phase C is a leading phase, and the phase B is a lagging phase; if the phase B in the system is a fault phase, the phase A is a leading phase, and the phase C is a lagging phase; if the system C phase is a fault phase, the B phase is a leading phase, and the A phase is a lagging phase.
The invention provides a phasor product active method, wherein the included angle of two phasors is acute angle and positive active power, the included angle is obtuse angle and negative active power, the reference phasor is set according to the phase region in which the fault phasor falls, so that the included angle between the reference phasor and the fault phasor can be kept at an acute angle under any condition, and reliable guarantee is provided for qualitatively judging the fault phasor and selecting a line.
The device for judging the fault phase and the line selection by the phasor product active power method is originally created, judges the fault phase and the line selection qualitatively rather than quantitatively, does not depend on accurate calculation of each fault quantity to carry out judgment, does not need Fourier transform and other accurate calculation of the fault quantity, thereby abandoning the transient process in which the variable magic measurement is difficult to capture the law, and eliminating the complicated transient data to judge the fault phase and the line selection, thereby realizing the hundred percent of accuracy.
In specific implementation, for a G-phase single-phase earth fault of a system, fault phase judgment is carried out according to any criterion as follows:
criterion 1: multiplying the fault phasor by the fault phasor, namely: will be provided with
Figure BDA00020043863700001019
Are respectively connected with
Figure BDA00020043863700001020
And
Figure BDA00020043863700001021
multiply to obtain
Figure BDA00020043863700001022
Figure BDA00020043863700001023
And
Figure BDA00020043863700001024
wherein,
Figure BDA00020043863700001025
the phasor product of (a) is the largest and positive in active power;
referring to fig. 1, the fault point falls on a fault point trajectory semicircle, regardless of the ground impedance, and, in addition to the metallic ground,
Figure BDA00020043863700001026
and
Figure BDA00020043863700001027
included angle less than
Figure BDA00020043863700001028
And
Figure BDA00020043863700001029
at an included angle, an
Figure BDA00020043863700001030
Is greater than
Figure BDA00020043863700001031
Of a die, thereby
Figure BDA00020043863700001032
The phasor product active power is greater than
Figure BDA00020043863700001033
The phasor product of (a) is active, and the two are equal when the metal is grounded;
Figure BDA00020043863700001034
and
Figure BDA00020043863700001035
included angle of 90 deg., so
Figure BDA00020043863700001036
And
Figure BDA00020043863700001037
the phasor product of (2) is 0, so
Figure BDA00020043863700001038
And the leading phase
Figure BDA00020043863700001039
The phasor product of (a) is the largest and positive.
Criterion 2: multiplying the fault phasor by the three-phase symmetric reference phasor, namely: will be provided with
Figure BDA00020043863700001040
Are respectively connected with
Figure BDA00020043863700001041
And
Figure BDA00020043863700001042
multiply to obtain
Figure BDA00020043863700001043
And
Figure BDA00020043863700001044
wherein,
Figure BDA00020043863700001045
the phasor product of (a) is the largest and positive in active power;
referring to fig. 1, no matter how large the ground impedance is, the fault point falls on the fault point trajectory semicircle,
Figure BDA00020043863700001046
advance in
Figure BDA00020043863700001047
The phase is between-30 degrees and 60 degrees, the included angle between the two is always acute angle of 60 degrees at most, the included angle is 60 degrees when the two are grounded by metal, the included angle is less than 60 degrees in other cases,
Figure BDA0002004386370000111
the phasor product active of (a) is positive;
Figure BDA0002004386370000112
advance in
Figure BDA0002004386370000113
The phase is between 60 DEG and 150 DEG, the metallic grounding is 60 DEG, and the other conditions are all more than 60 DEG,
Figure BDA0002004386370000114
and
Figure BDA0002004386370000115
the moulds are the same, and the mould is the same,
Figure BDA0002004386370000116
the phasor product active power is greater than
Figure BDA0002004386370000117
The phasor product of (a) is active;
Figure BDA0002004386370000118
and
Figure BDA0002004386370000119
the included angle is 90-180 degrees,
Figure BDA00020043863700001110
the phasor product of (c) has a positive value. Therefore, the temperature of the molten metal is controlled,
Figure BDA00020043863700001111
the phasor product of (a) is the largest and positive.
Criterion 3: multiplying the fault phasor by the three-phase symmetric reference phasor, namely: will be provided with
Figure BDA00020043863700001112
Are respectively connected with
Figure BDA00020043863700001113
And
Figure BDA00020043863700001114
multiply to obtain
Figure BDA00020043863700001115
And
Figure BDA00020043863700001116
wherein,
Figure BDA00020043863700001117
the phasor product of (a) is the largest and positive in active power;
referring to fig. 1, no matter how large the ground impedance is, the fault point falls on the fault point trajectory semicircle,
Figure BDA00020043863700001118
advance in
Figure BDA00020043863700001119
The phase is between-60 degrees and 30 degrees, the included angle between the two is always acute angle of 60 degrees at most, the included angle is 30 degrees when the metal is grounded, the included angle is less than 60 degrees in other cases,
Figure BDA00020043863700001120
the phasor product active of (a) is positive;
Figure BDA00020043863700001121
advance in
Figure BDA00020043863700001122
The phase is between 90 DEG and 180 DEG, the metallic grounding is 90 DEG, and the other conditions are all larger than 90 DEG,
Figure BDA00020043863700001123
the phasor product active power of (a) is a negative value;
Figure BDA00020043863700001124
and
Figure BDA00020043863700001125
the included angle is 60-150 degrees,
Figure BDA00020043863700001126
and
Figure BDA00020043863700001127
the included angle is always larger than 60 degrees,
Figure BDA00020043863700001128
the phasor product active power is always less than
Figure BDA00020043863700001129
The phasor product of (a) is active. Therefore, the temperature of the molten metal is controlled,
Figure BDA00020043863700001130
the phasor product of (a) is the largest and positive.
Criterion 4: multiplying the fault phasor by the three-phase symmetric reference phasor, namely:
Figure BDA00020043863700001131
and
Figure BDA00020043863700001132
respectively with the same name
Figure BDA00020043863700001133
Figure BDA00020043863700001134
And
Figure BDA00020043863700001135
multiplying to obtain:
Figure BDA00020043863700001136
and
Figure BDA00020043863700001137
wherein,
Figure BDA00020043863700001138
the phasor product of (a) is the largest and positive in active power;
referring to fig. 1, no matter how large the ground impedance is, the fault point falls on the fault point trajectory semicircle,
Figure BDA00020043863700001139
and at the same ground impedance
Figure BDA00020043863700001140
And
Figure BDA00020043863700001141
included angle less than
Figure BDA00020043863700001142
And
Figure BDA00020043863700001143
at an angle of inclination of
Figure BDA00020043863700001144
Figure BDA00020043863700001145
And at the same ground impedance
Figure BDA00020043863700001146
And
Figure BDA00020043863700001147
included angle less than
Figure BDA00020043863700001148
And
Figure BDA00020043863700001149
at an angle of inclination of
Figure BDA00020043863700001150
Figure BDA00020043863700001151
The phasor product of (a) is active; therefore, the temperature of the molten metal is controlled,
Figure BDA00020043863700001152
the phasor product of (a) is the largest and positive.
Criterion 5: multiplying the fault phasor by the three-phase symmetric reference phasor, namely: will be provided with
Figure BDA00020043863700001153
And
Figure BDA00020043863700001154
respectively with the same name
Figure BDA00020043863700001155
Figure BDA00020043863700001156
And
Figure BDA00020043863700001157
multiply to obtain
Figure BDA00020043863700001158
And
Figure BDA00020043863700001159
wherein,
Figure BDA00020043863700001160
the phasor product of (a) is the largest and positive in active power;
referring to fig. 1, no matter how large the ground impedance is, the fault point falls on the fault point trajectory semicircle,
Figure BDA00020043863700001161
and at the same ground impedance
Figure BDA00020043863700001162
And
Figure BDA00020043863700001163
included angle less than
Figure BDA00020043863700001164
And
Figure BDA00020043863700001165
at an angle of inclination of
Figure BDA00020043863700001166
Figure BDA00020043863700001167
Figure BDA00020043863700001168
Figure BDA00020043863700001169
Therefore, the temperature of the molten metal is controlled,
Figure BDA00020043863700001170
the phasor product of (a) is the largest and positive.
Criterion 6: multiplying the fault phasor by the three-phase symmetric reference phasor, namely: will be provided with
Figure BDA00020043863700001171
Are respectively connected with
Figure BDA00020043863700001172
And
Figure BDA00020043863700001173
multiplying to obtain:
Figure BDA00020043863700001174
and
Figure BDA00020043863700001175
wherein
Figure BDA00020043863700001176
The phasor product of (a) is the largest and positive in active power;
Figure BDA00020043863700001177
and
Figure BDA00020043863700001178
to construct a set of three-phase symmetric reference phasors
Figure BDA00020043863700001179
And
Figure BDA00020043863700001180
leading three-phase voltage
Figure BDA00020043863700001181
And
Figure BDA00020043863700001182
are all in phase
Figure BDA00020043863700001183
Will be provided with
Figure BDA00020043863700001184
The value is randomly selected in the range of (-30 degrees and 60 degrees); or will be
Figure BDA00020043863700001185
Tracking neutral voltage according to equations (2.1) and (2.2)
Figure BDA00020043863700001186
Dynamically take value to
Figure BDA00020043863700001187
And
Figure BDA00020043863700001188
the included angle of (a) is acute and minimal.
With reference to figure 1 of the drawings,
Figure BDA0002004386370000121
advance in
Figure BDA0002004386370000122
The phase position is between-30 degrees and 60 degrees,
Figure BDA0002004386370000123
the optimal value of the fault point is 15 degrees, the fault point falls on any point on the semicircle of the fault point track,
Figure BDA0002004386370000124
with three-phase symmetrical reference phasors constructed
Figure BDA0002004386370000125
And
Figure BDA0002004386370000126
in (1)
Figure BDA0002004386370000127
The included angles are all less than 45 degrees, which is most beneficial
Figure BDA0002004386370000128
The phasor product of (a) is the largest.
Of course, it is also possible to
Figure BDA0002004386370000129
Tracking neutral voltage
Figure BDA00020043863700001210
The dynamic value of the numerical control system is taken,
Figure BDA00020043863700001211
advance in
Figure BDA00020043863700001212
Make it
Figure BDA00020043863700001213
And
Figure BDA00020043863700001214
is acute and close to 0, then,
Figure BDA00020043863700001215
the phasor product of the three-phase current transformer is more outstanding in power, and is more beneficial to fault phase judgment.
Criterion 7: multiplying the fault phasor by the three-phase symmetric reference phasor, namely: will be provided with
Figure BDA00020043863700001216
And
Figure BDA00020043863700001217
respectively with the same name
Figure BDA00020043863700001218
Figure BDA00020043863700001219
And
Figure BDA00020043863700001220
multiplying to obtain:
Figure BDA00020043863700001221
and
Figure BDA00020043863700001222
wherein,
Figure BDA00020043863700001223
the phasor product of (a) is the largest and positive in active power;
Figure BDA00020043863700001224
and
Figure BDA00020043863700001225
to construct a set of three-phase symmetric reference phasors
Figure BDA00020043863700001226
And
Figure BDA00020043863700001227
leading and triphase phase voltages
Figure BDA00020043863700001228
And
Figure BDA00020043863700001229
are all in phase
Figure BDA00020043863700001230
Will be provided with
Figure BDA00020043863700001231
Any value is taken in the range of (-30.5 degrees and 59.5 degrees); or will be
Figure BDA00020043863700001232
Tracking neutral voltage according to equations (2.1) and (2.3)
Figure BDA00020043863700001233
Dynamically take value to
Figure BDA00020043863700001234
And
Figure BDA00020043863700001235
the included angle of (a) is acute and minimal.
With reference to figure 1 of the drawings,
Figure BDA00020043863700001236
advance in
Figure BDA00020043863700001237
The phase position is between-3 degrees and 30 degrees,
Figure BDA00020043863700001238
the optimal value of the fault point is 13.5 degrees, the fault point falls on any point on the semicircle of the fault point track,
Figure BDA00020043863700001239
with three-phase symmetrical reference phasors constructed
Figure BDA00020043863700001240
And
Figure BDA00020043863700001241
in (1)
Figure BDA00020043863700001242
The included angles are all less than 16.5 degrees, which is most beneficial
Figure BDA00020043863700001243
The phasor product of (a) is the largest.
Of course, it is also possible to
Figure BDA00020043863700001244
Tracking neutral voltage
Figure BDA00020043863700001245
Dynamically take value to
Figure BDA00020043863700001246
And
Figure BDA00020043863700001247
is acute and close to 0, then,
Figure BDA00020043863700001248
the phasor product of the three-phase current transformer is more outstanding in power, and is more beneficial to fault phase judgment.
For intermittent arc grounding, the criterion of the fault phase of the invention is still valid and has higher accuracy:
referring to fig. 2, the intermittent single-phase grounding for power frequency arc quenching is realized by that, at the moment of arc quenching,
Figure BDA00020043863700001249
is perpendicular to the Y-axis,
Figure BDA00020043863700001250
is/are as follows
Figure BDA00020043863700001251
At the maximum, the number of the first,
Figure BDA00020043863700001252
and
Figure BDA00020043863700001253
the positive and negative values are in the same direction, namely in the same positive and negative directions, or in the same negative direction; moment of arc extinction
Figure BDA00020043863700001254
Figure BDA00020043863700001255
After the arc is extinguished,
Figure BDA00020043863700001256
a constant value equal to the arc-quenching time, and a leading phase voltage relative to ground
Figure BDA00020043863700001257
Figure BDA00020043863700001258
Until the arc light is re-ignited at the next fault point,
Figure BDA00020043863700001259
and
Figure BDA00020043863700001260
the same positive and negative then
Figure BDA00020043863700001261
Figure BDA00020043863700001262
The phasor product of (a) is still positive and maximal.
For the single-phase grounding of high-frequency arc quenching, the high-frequency arc quenching time and the power frequency arc quenching time have the same voltage memory characteristics:
Figure BDA00020043863700001263
and
Figure BDA00020043863700001264
the judgment method has the advantages that the judgment is carried out in the same direction, namely, in the same positive and negative directions, and is positive or negative at the same time, so that the judgment accuracy is not influenced, and the judgment accuracy is improved.
Any one of the above features may be used to determine a faulty phase, or two or more features may be used together to determine a faulty phase.
The phasor product of the invention actively judges a plurality of characteristic criteria given by a fault phase, and the plurality of criteria can be verified mutually, thus effectively ensuring the accuracy of the invention in judging the fault phase by one hundred percent and overcoming the technical problem that the fault phase is difficult to accurately judge.
In specific implementation, for the G-phase single-phase earth fault of the system, the capacitance current I of the jth non-fault lineCjCharacterized by the formula (3.1):
Figure BDA0002004386370000131
capacitive current of faulty line
Figure BDA0002004386370000132
Characterized by the formula (3.2)
Figure BDA0002004386370000133
XCCapacitive current of non-faulty line for system to ground capacitive reactance
Figure BDA0002004386370000134
And fault line capacitance current
Figure BDA0002004386370000135
Has a phase difference of 180 DEG, and a fault line capacitance current
Figure BDA0002004386370000136
Voltage to fault
Figure BDA0002004386370000137
In-phase and lagging neutral voltage
Figure BDA0002004386370000138
The phase position is 90 degrees,
Figure BDA0002004386370000139
and
Figure BDA00020043863700001310
all leading the fault phase voltage
Figure BDA00020043863700001311
Is between 0 and 90 degrees.
And carrying out fault line selection according to any line selection criterion from the following criteria I to the third criterion:
criterion one is as follows: and multiplying the fault phasor by the line selection reference phasor to obtain a phasor product active power, namely: each line to be led out
Figure BDA00020043863700001312
And
Figure BDA00020043863700001313
obtained by multiplication
Figure BDA00020043863700001314
Phasor product active power of fault line
Figure BDA00020043863700001315
Is all that
Figure BDA00020043863700001316
The medium phasor product has the largest active power and is a positive value.
Referring to fig. 1, the capacitive current of the faulty line
Figure BDA00020043863700001317
Advance in
Figure BDA00020043863700001318
The included angle of the two is less than 60 degrees and is between-30 degrees and 60 degrees, but not the fault phase capacitance current
Figure BDA00020043863700001319
And iCThe phase difference is 180 degrees,
Figure BDA00020043863700001320
the phasor product of (a) is positive,
Figure BDA00020043863700001321
the middle power is negative, therefore,
Figure BDA00020043863700001322
the phasor product of (1) is
Figure BDA00020043863700001323
The active power is the largest and positive.
Criterion two: and multiplying the fault phasor by the fault phasor and the line selection reference phasor to obtain a phasor product active:
if it is
Figure BDA00020043863700001324
Multiplying the fault phasor by the fault phasor to obtain phasor product active power, each outgoing line
Figure BDA00020043863700001325
And
Figure BDA00020043863700001326
obtained by multiplication
Figure BDA00020043863700001327
Phasor product active power of fault line
Figure BDA00020043863700001328
Is all that
Figure BDA00020043863700001329
The medium phasor product has the largest active power and is a positive value;
if it is
Figure BDA00020043863700001330
And then, multiplying the fault phasor by the line selection reference phasor to obtain a phasor product active power, namely: each line to be led out
Figure BDA00020043863700001331
And
Figure BDA00020043863700001332
obtained by multiplication
Figure BDA00020043863700001333
Phasor product active power of fault line
Figure BDA00020043863700001334
Is all that
Figure BDA00020043863700001335
The medium phasor product has the largest active power and is a positive value;
while the capacitance current of the fault line is in phase with the fault phase-to-ground voltage, the capacitance current of the fault line is in metallic grounding
Figure BDA00020043863700001336
Near metallic ground
Figure BDA00020043863700001337
Is also very small, the transient process is easy to generate adverse effect, and is not beneficial to the value of phasor product success, so the criterion setting
Figure BDA00020043863700001338
Avoiding single-phase earthing close to metallic earthing, multiplying fault phasor by fault phasor, of each outgoing line
Figure BDA00020043863700001339
And
Figure BDA00020043863700001340
the multiplication is carried out in such a way that,
Figure BDA00020043863700001341
the phasor product of (1) is
Figure BDA00020043863700001342
The middle active power is the largest and positive; for single-phase earthing close to metallic earthing, i.e.
Figure BDA00020043863700001343
While, each line is out
Figure BDA00020043863700001344
And
Figure BDA00020043863700001345
the multiplication is carried out in such a way that,
Figure BDA00020043863700001346
the phasor product of (1) is
Figure BDA00020043863700001347
The active power is the largest and positive.
Criterion three: and multiplying the fault phasor by the line selection reference phasor to obtain a phasor product active power, namely: each line to be led out
Figure BDA00020043863700001348
And
Figure BDA00020043863700001349
obtained by multiplication
Figure BDA00020043863700001350
Phasor product active power of fault line
Figure BDA00020043863700001351
Is all that
Figure BDA00020043863700001352
The medium phasor product has the largest active power and is a positive value.
With reference to figure 1 of the drawings,
Figure BDA00020043863700001353
advance in
Figure BDA00020043863700001354
Phase 90-180 DEG, capacitance current of fault line
Figure BDA00020043863700001355
Hysteresis
Figure BDA00020043863700001356
The phase position is 90 degrees,
Figure BDA00020043863700001357
advance in
Figure BDA00020043863700001358
The phase is 0 to 90 degrees,
Figure BDA00020043863700001359
is preferably 45 deg., so that
Figure BDA00020043863700001360
And
Figure BDA00020043863700001361
the included angle of (a) is acute under various grounding conditions,
Figure BDA00020043863700001362
the phasor product of (1) is
Figure BDA00020043863700001363
The active power is the largest and positive.
Of course, it is also possible to
Figure BDA0002004386370000141
Tracking neutral voltage
Figure BDA0002004386370000142
The dynamic value of the numerical control system is taken,
Figure BDA0002004386370000143
so that
Figure BDA0002004386370000144
And
Figure BDA0002004386370000145
is acute and close to 0, then,
Figure BDA0002004386370000146
the phasor product of (1) is
Figure BDA0002004386370000147
The active power is the largest and positive.
If the included angle between the reference phasor and the fault phasor is obtuse, i.e. the direction of the reference phasor is opposite to that of the fault phasor, the phasor product active of the reference phasor and the fault phasor is the most negative.
Any one of the above features may be used to determine a faulty phase, or two or more features may be used together to determine a faulty phase.
The phasor product active line selection method provides three characteristic criteria which can be verified mutually, thus effectively guaranteeing the accuracy of the line selection method in one hundred percent and overcoming the technical problem of line selection.
In particular embodiments, e.g. let t1Time phasor
Figure BDA0002004386370000148
And
Figure BDA0002004386370000149
respectively, are denoted as a (t)1) And b (t)1) Phasor of
Figure BDA00020043863700001410
Is phasor
Figure BDA00020043863700001411
And phasor
Figure BDA00020043863700001412
Sum, phasor
Figure BDA00020043863700001413
Is phasor
Figure BDA00020043863700001414
And phasor
Figure BDA00020043863700001415
The difference is t1Time phasor
Figure BDA00020043863700001416
Sample value c (t) of1) And phasor
Figure BDA00020043863700001417
The sampled values d (τ) of (d) are:
Figure BDA00020043863700001418
therefore, when the system generates G-phase single-phase grounding, phase voltage sampling values of three phases are obtained in any mode as follows:
the first method is as follows: leading phase voltage
Figure BDA00020043863700001419
Voltage of lagging phase
Figure BDA00020043863700001420
And fault phase voltage
Figure BDA00020043863700001421
Is equal to the sampling value of the phase-to-ground voltage of the same name phase minus the synchronous sampling value of the neutral point voltage, and is represented by the formula (5.1);
Figure BDA00020043863700001422
the second method comprises the following steps: a voltage transformer is adopted for measurement, the voltage of the secondary side of the voltage transformer is sampled to obtain a phase voltage sampling value, and the neutral point of the primary side of the voltage transformer is not grounded.
The neutral points of the three voltage transformers are not grounded, phase voltages are output from the secondary sides of the voltage transformers instead of relative ground voltages, the system is grounded in a single phase, the voltage output from the secondary sides of the voltage transformers cannot change, and a transient process cannot occur.
The third method comprises the following steps: leading phase voltage
Figure BDA00020043863700001423
HysteresisPhase voltage
Figure BDA00020043863700001424
And fault phase voltage
Figure BDA00020043863700001425
The sampling value of (2) is obtained according to an equipotential sampling value of the three-phase earth voltage before the single-phase earth fault, wherein the equipotential sampling value refers to:
sampling is carried out on an alternating current signal f (T) with the period T, and the alternating current signal f (T) when the system normally operates is recorded as f1(t) mixing tτThe AC signal f (t) after the system fault at the moment is recorded as f2(t)，f1(t) after the occurrence of a failure t2Sampling value f of time1(t2) And has the following components:
Figure BDA00020043863700001426
k is a natural number not less than 1, f1(t1) Is f1(t2) Before failure, then:
f1(t2)＝f1(t1) (5.3)
f (t) at t2Fault increment at time:
Δf(t2)＝f2(t2)-f1(t2) (5.4)
f (t) represents the relative voltage of the system, f1(t) represents the phase voltage of the system
Figure BDA0002004386370000151
And
Figure BDA0002004386370000152
with f2(t) represents the relative ground voltage of the system after single-phase grounding
Figure BDA0002004386370000153
And
Figure BDA0002004386370000154
normal operation of the system f (t) ═ f1(t), f (t) f after single-phase grounding2(t)。
The invention provides an algorithm of an equipotential sampling value of a phase voltage after a fault, provides a basic condition for selection of a reference phasor, and is suitable for all vectors.
The sampling value of the system line voltage is obtained by subtracting the synchronous sampling values of the two phase voltages; or the sampling value of the system line voltage is obtained by subtracting the synchronous sampling values of two phase-to-ground voltages, and the system line voltage refers to the voltage of the leading phase line in the system
Figure BDA0002004386370000155
Voltage of lagging phase line
Figure BDA0002004386370000156
And fault phase line voltage
Figure BDA0002004386370000157
In a specific implementation, line voltages of a leading relative fault phase, a lagging relative leading phase and a fault relative lagging phase are calculated according to equation (5.1.1)
Figure BDA0002004386370000158
And
Figure BDA0002004386370000159
is obtained by any of the following ways:
the first mode is as follows: according to the formula (2.1),
Figure BDA00020043863700001510
and
Figure BDA00020043863700001511
the sampled values are respectively composed of the phase voltages of a leading phase, a lagging phase and a fault phase
Figure BDA00020043863700001512
And
Figure BDA00020043863700001513
subtracting the synchronous sampling values to obtain;
the second mode is as follows: according to the formula (6.1),
Figure BDA00020043863700001514
and
Figure BDA00020043863700001515
the sampling values of the two phases are respectively from the voltages to the ground of the leading phase, the lagging phase and the fault phase
Figure BDA00020043863700001516
And
Figure BDA00020043863700001517
subtracting the synchronous sampling values to obtain;
Figure BDA00020043863700001518
and if the difference between the two phasors is equal to the third phasor, subtracting the synchronous sampling value of the two phasors by the synchronous sampling value of the third phasor, and applying to vector subtraction operation.
In specific implementation, the sampling value of the neutral point voltage is obtained by adding synchronous sampling values of three phases of voltages relative to the ground according to the formula (2.1), or is obtained by converting the sampling value of the open triangular voltage of the voltage transformer;
and if the sum of the two phasors is equal to the third phasor, adding the synchronous sampling values of the two phasors to the synchronous sampling value of the third phasor, and applying to vector addition operation.
The sampling value of the line voltage is obtained by directly subtracting the sampling values of the phase voltages, and a new method is provided for calculating vector sum and difference sampling values.
The phasor product active method for judging the fault phase and the line selection criterion in the line selection method are suitable for a power grid system with a neutral point resistor grounded.
The current generated when the neutral point resistor is grounded to the single-phase ground is basically in the same phase with the fault phase voltage, and the phase angle leads the fault phase voltage after the current is superposed with the capacitance current, so that the accuracy of the line selection criterion of the invention is not influenced, and the accuracy of line selection is facilitated.
However, in a power grid system with a neutral point arc suppression coil grounded, one arc suppression coil may have two operation states of overcompensation and undercompensation along with the change of the system operation mode, the accuracy of the line selection criterion of the invention is not affected by the undercompensation, but the accuracy of the invention is affected by the overcompensation, and the invention must be corrected.
When the G phase of the system is grounded in a stable state, the fault phase is grounded relative to the voltage
Figure BDA0002004386370000161
Voltage of lagging neutral point
Figure BDA0002004386370000162
Phase 90 deg., and perpendicular to each other, so that the fault is at earth voltage
Figure BDA0002004386370000163
And neutral point voltage
Figure BDA0002004386370000164
Multiply to obtain
Figure BDA0002004386370000165
Active of is equal to 0.
In specific implementation, phasors are set
Figure BDA0002004386370000166
And phasor
Figure BDA0002004386370000167
The phasor product active power of is WE1*F1Phasors
Figure BDA0002004386370000168
And phasor
Figure BDA0002004386370000169
The phasor product active power of is WE2*F2(ii) a If WE1*F1≥WE2*F2Then the accumulated value of the phasor product of more than half cycle also satisfies:
Figure BDA00020043863700001610
or, the average value of more than half cycle also satisfies:
Figure BDA00020043863700001611
n1is a number of samples greater than half a cycle time period, uE1(ti)、uF1(ti)、uE2(ti) And uF2(ti) Are respectively as
Figure BDA00020043863700001612
Figure BDA00020043863700001613
And
Figure BDA00020043863700001614
at tiThe sampled value of the moment.
In practical application, the accumulated value of the phasor product exceeding half cycle is directly used for replacing the phasor product active power to implement comparison, so that calculation can be reduced, and rapid fault judgment is facilitated.

Claims (9)

1. The phasor product active method for judging fault phase and selecting line is characterized by that:
phasors
Figure FDA0002708600630000011
Is expressed as uE(t) is: u. ofE(t)＝Ksin(ωt+α)，
Phasors
Figure FDA0002708600630000012
Is expressed as uF(t) is: u. ofF(t)＝Psin(ωt+α+β)，
K and P are phasors
Figure FDA0002708600630000013
And phasor
Figure FDA0002708600630000014
A and a + beta are phasors, respectively
Figure FDA0002708600630000015
And phasor
Figure FDA0002708600630000016
Beta is phasor
Figure FDA0002708600630000017
And phasor
Figure FDA0002708600630000018
The included angle of (A);
phasor
Figure FDA0002708600630000019
And phasor
Figure FDA00027086006300000110
Phasor product of
Figure FDA00027086006300000111
Is marked as
Figure FDA00027086006300000112
Phasor product
Figure FDA00027086006300000113
The phasor product of (A) is recorded as WE*F；
WE*F＝KPcosβ
Phasor product
Figure FDA00027086006300000114
Phasor of (2) by active power WE*FIs characterized by equation (1.1):
Figure FDA00027086006300000115
uE(ti)、uF(ti) And g (t)i) Are phasors, respectively
Figure FDA00027086006300000116
Phasors
Figure FDA00027086006300000117
Product of sum and phasor
Figure FDA00027086006300000118
At tiSynchronous sampled values of time, n being phasor
Figure FDA00027086006300000119
And phasor
Figure FDA00027086006300000120
The sampling number of half cycle or integral multiple of half cycle, and n is a natural number not less than 2;
the criterion characterized by equation (1.2) is obtained according to equation (1.1):
Figure FDA00027086006300000121
and calculating phasor product active power according to the formula (1.1), and judging the phase relation between phasors according to the formula (1.2) and the magnitude and the positive and negative of the phasor product active power to realize the judgment and line selection of the fault phase during single-phase grounding.
2. The phasor product active method for determining a faulty phase and selecting a line according to claim 1, characterized in that:
for a power grid system with m outgoing lines, when a single-phase earth fault occurs in the power grid system,
to be provided with
Figure FDA00027086006300000122
And
Figure FDA00027086006300000123
representing the phase voltages of the leading phase, lagging phase and faulted phase, respectively, and applying the same
Figure FDA00027086006300000124
And
Figure FDA00027086006300000125
defining a set of three-phase symmetrical reference phasors;
to be provided with
Figure FDA00027086006300000126
And
Figure FDA00027086006300000127
respectively representing line voltages of a leading phase relative to a fault phase, a lagging phase relative to a leading phase and a lagging phase relative to a fault phase, and converting the line voltages into the voltage values
Figure FDA00027086006300000128
And
Figure FDA00027086006300000129
defining as another set of three-phase symmetrical reference phasors, dividing said set
Figure FDA00027086006300000130
Definition ofReferencing phasors for line selection;
to be provided with
Figure FDA00027086006300000131
And
Figure FDA00027086006300000132
respectively representing the voltages relative to the ground of the leading phase, the lagging phase and the fault phase to
Figure FDA00027086006300000133
Represents a neutral point voltage, by
Figure FDA00027086006300000134
And
Figure FDA00027086006300000135
defining as a fault phasor;
theta represents phasor
Figure FDA00027086006300000136
And phasor
Figure FDA00027086006300000137
The included angle of (A);
to be provided with
Figure FDA0002708600630000021
Represents the capacitance current of the ith outgoing line, i is 1,2
Figure FDA0002708600630000022
Representing the capacitive current of the faulty line,
Figure FDA0002708600630000023
and
Figure FDA0002708600630000024
for fault phasor, there is a relation (2.1)：
Figure FDA0002708600630000025
Constructing a set of three-phase symmetric reference phasors
Figure FDA0002708600630000026
And
Figure FDA0002708600630000027
the three-phase symmetrical reference phasor
Figure FDA0002708600630000028
And
Figure FDA0002708600630000029
leading three-phase voltage
Figure FDA00027086006300000210
And
Figure FDA00027086006300000211
are all in phase
Figure FDA00027086006300000212
Will be provided with
Figure FDA00027086006300000213
The value is randomly selected in the range of (-30 degrees and 60 degrees); or will be
Figure FDA00027086006300000214
Tracking neutral voltage according to equations (2.1) and (2.2)
Figure FDA00027086006300000215
Dynamically take value to
Figure FDA00027086006300000216
And
Figure FDA00027086006300000217
the included angle is acute and minimum;
Figure FDA00027086006300000218
constructing a set of three-phase symmetric reference phasors
Figure FDA00027086006300000219
And
Figure FDA00027086006300000220
the three-phase symmetrical reference phasor
Figure FDA00027086006300000221
And
Figure FDA00027086006300000222
leading three-phase voltage
Figure FDA00027086006300000223
And
Figure FDA00027086006300000224
are all in phase
Figure FDA00027086006300000225
Will be provided with
Figure FDA00027086006300000226
Any value is taken in the range of (-30.5 degrees and 59.5 degrees); or will be
Figure FDA00027086006300000227
Tracking neutral voltage according to equations (2.1) and (2.3)
Figure FDA00027086006300000228
Dynamically take value to
Figure FDA00027086006300000229
And
Figure FDA00027086006300000230
the included angle is acute and minimum;
Figure FDA00027086006300000231
constructing a line selection reference phasor
Figure FDA00027086006300000232
The reference phasor
Figure FDA00027086006300000233
Advance in
Figure FDA00027086006300000234
Phase is
Figure FDA00027086006300000235
Will be provided with
Figure FDA00027086006300000236
The value is randomly selected in the interval of (0 degrees and 90 degrees); or will be
Figure FDA00027086006300000237
Tracking neutral voltage according to equations (2.1) and (2.4)
Figure FDA00027086006300000238
Dynamically take value to
Figure FDA00027086006300000239
And
Figure FDA00027086006300000240
the included angle is acute and minimum;
Figure FDA00027086006300000241
the phasor product for judging a fault phase by a power method is as follows: multiplying the fault phasor by the fault phasor or multiplying the fault phasor by the three-phase symmetrical reference phasor;
the phasor product for realizing the line selection by the power method is as follows: and multiplying the capacitance current of each outgoing line by the reference phasor of the selected line, or multiplying the capacitance current of each outgoing line by the voltage of the fault phase-to-ground.
3. The phasor product active method for determining a faulty phase and selecting a line according to claim 2, characterized in that:
and aiming at the G-phase single-phase earth fault of the system, judging the fault phase according to any criterion as follows:
criterion 1: multiplying the fault phasor by the fault phasor, namely: will be provided with
Figure FDA00027086006300000242
Are respectively connected with
Figure FDA00027086006300000243
And
Figure FDA00027086006300000244
multiply to obtain
Figure FDA00027086006300000245
And
Figure FDA00027086006300000246
wherein,
Figure FDA00027086006300000247
the phasor product of (a) is the largest and positive in active power;
criterion 2: the fault phasor is compared withThree-phase symmetric reference phasor multiplication, namely: will be provided with
Figure FDA00027086006300000248
Are respectively connected with
Figure FDA00027086006300000249
And
Figure FDA00027086006300000250
multiply to obtain
Figure FDA00027086006300000251
And
Figure FDA00027086006300000252
wherein,
Figure FDA00027086006300000253
the phasor product of (a) is the largest and positive in active power;
criterion 3: multiplying the fault phasor by the three-phase symmetric reference phasor, namely: will be provided with
Figure FDA0002708600630000031
Are respectively connected with
Figure FDA0002708600630000032
And
Figure FDA0002708600630000033
multiply to obtain
Figure FDA0002708600630000034
And
Figure FDA0002708600630000035
wherein,
Figure FDA0002708600630000036
the phasor product of (a) is the largest and positive in active power;
criterion 4: multiplying the fault phasor by the three-phase symmetric reference phasor, namely:
Figure FDA0002708600630000037
and
Figure FDA0002708600630000038
respectively with the same name
Figure FDA0002708600630000039
And
Figure FDA00027086006300000310
multiplying to obtain:
Figure FDA00027086006300000311
and
Figure FDA00027086006300000312
wherein,
Figure FDA00027086006300000313
the phasor product of (a) is the largest and positive in active power;
criterion 5: multiplying the fault phasor by the three-phase symmetric reference phasor, namely: will be provided with
Figure FDA00027086006300000314
And
Figure FDA00027086006300000315
respectively with the same name
Figure FDA00027086006300000316
And
Figure FDA00027086006300000317
multiply to obtain
Figure FDA00027086006300000318
And
Figure FDA00027086006300000319
wherein,
Figure FDA00027086006300000320
the phasor product of (a) is the largest and positive in active power;
criterion 6: multiplying the fault phasor by the three-phase symmetric reference phasor, namely: will be provided with
Figure FDA00027086006300000321
Are respectively connected with
Figure FDA00027086006300000322
And
Figure FDA00027086006300000323
multiplying to obtain:
Figure FDA00027086006300000324
and
Figure FDA00027086006300000325
wherein
Figure FDA00027086006300000326
The phasor product of (a) is the largest and positive in active power;
criterion 7: multiplying the fault phasor by the three-phase symmetric reference phasor, namely: will be provided with
Figure FDA00027086006300000327
And
Figure FDA00027086006300000328
respectively with the same name
Figure FDA00027086006300000329
And
Figure FDA00027086006300000330
multiplying to obtain:
Figure FDA00027086006300000331
and
Figure FDA00027086006300000332
wherein,
Figure FDA00027086006300000333
the phasor product of (a) is the largest and positive.
4. The phasor product active method for determining a faulty phase and selecting a line according to claim 2, characterized in that:
and aiming at the G-phase single-phase earth fault of the system, fault line selection is carried out according to any line selection criterion from the following criteria I to the third criterion:
criterion one is as follows: and multiplying the fault phasor by the line selection reference phasor to obtain a phasor product active power, namely: each line to be led out
Figure FDA00027086006300000334
And
Figure FDA00027086006300000335
obtained by multiplication
Figure FDA00027086006300000336
Phasor product active power of fault line
Figure FDA00027086006300000337
Is all that
Figure FDA00027086006300000338
The medium phasor product has the largest active power and is a positive value;
criterion two: and multiplying the fault phasor by the fault phasor and the line selection reference phasor to obtain a phasor product active:
if it is
Figure FDA00027086006300000339
Multiplying the fault phasor by the fault phasor to obtain phasor product active power, each outgoing line
Figure FDA00027086006300000340
And
Figure FDA00027086006300000341
obtained by multiplication
Figure FDA00027086006300000342
Phasor product active power of fault line
Figure FDA00027086006300000343
Is all that
Figure FDA00027086006300000344
The medium phasor product has the largest active power and is a positive value;
if it is
Figure FDA00027086006300000345
And then, multiplying the fault phasor by the line selection reference phasor to obtain a phasor product active power, namely: each line to be led out
Figure FDA00027086006300000346
And
Figure FDA00027086006300000347
obtained by multiplication
Figure FDA00027086006300000348
Phasor product active power of fault line
Figure FDA00027086006300000349
Is all that
Figure FDA00027086006300000350
The medium phasor product has the largest active power and is a positive value;
criterion three: and multiplying the fault phasor by the line selection reference phasor to obtain a phasor product active power, namely: each line to be led out
Figure FDA00027086006300000351
And
Figure FDA00027086006300000358
obtained by multiplication
Figure FDA00027086006300000352
Phasor product active power of fault line
Figure FDA00027086006300000353
Is all that
Figure FDA00027086006300000354
The medium phasor product has the largest active power and is a positive value.
5. The phasor product active method for determining a faulty phase and selecting a line according to claim 2, characterized in that:
when G-phase single-phase grounding occurs in the system, phase voltage sampling values of three phases are obtained in any mode as follows:
the first method is as follows: leading phase voltage
Figure FDA00027086006300000355
Voltage of lagging phase
Figure FDA00027086006300000356
And fault phase voltage
Figure FDA00027086006300000357
Is equal to the sampling value of the phase-to-ground voltage of the same name phase minus the synchronous sampling value of the neutral point voltage, and is represented by the formula (5.1);
Figure FDA0002708600630000041
the second method comprises the following steps: measuring by adopting a voltage transformer, sampling the voltage of the secondary side of the voltage transformer to obtain a phase voltage sampling value, wherein the neutral point of the primary side of the voltage transformer is not grounded;
the third method comprises the following steps: leading phase voltage
Figure FDA0002708600630000042
Voltage of lagging phase
Figure FDA0002708600630000043
And fault phase voltage
Figure FDA0002708600630000044
The sampled value of (2) is obtained according to an equipotential sampled value of the three-phase ground voltage before the single-phase ground fault, wherein the equipotential sampled value refers to:
sampling is carried out on an alternating current signal f (T) with the period T, and the alternating current signal f (T) when the system normally operates is recorded as f1(t) mixing tτThe AC signal f (t) after the system fault at the moment is recorded as f2(t)，f1(t) after the occurrence of a failure t2Sampling value f of time1(t2) And has the following components:
Figure FDA0002708600630000045
k is a natural number not less than 1, f1(t1) Is f1(t2) Before failure, then:
f1(t2)＝f1(t1) (5.3)
f (t) at t2Fault increment at time:
Δf(t2)＝f2(t2)-f1(t2) (5.4)
f (t) represents the relative voltage of the system, f1(t) represents the phase voltage of the system
Figure FDA0002708600630000046
And
Figure FDA0002708600630000047
with f2(t) represents the relative ground voltage of the system after single-phase grounding
Figure FDA0002708600630000048
And
Figure FDA0002708600630000049
normal operation of the system f (t) ═ f1(t), f (t) f after single-phase grounding2(t)。
6. The phasor product active method for determining a faulty phase and selecting a line according to claim 2, characterized in that:
line voltage of leading phase to fault phase, lagging phase to leading phase and lagging phase to fault phase
Figure FDA00027086006300000410
And
Figure FDA00027086006300000411
is obtained by any of the following ways:
the first mode is as follows: according to the formula (2.1),
Figure FDA00027086006300000412
and
Figure FDA00027086006300000413
the sampled values are respectively composed of the phase voltages of a leading phase, a lagging phase and a fault phase
Figure FDA00027086006300000414
And
Figure FDA00027086006300000415
subtracting the synchronous sampling values to obtain;
the second mode is as follows: according to the formula (6.1),
Figure FDA00027086006300000416
and
Figure FDA00027086006300000417
the sampling values of the two phases are respectively from the voltages to the ground of the leading phase, the lagging phase and the fault phase
Figure FDA00027086006300000418
And
Figure FDA00027086006300000419
subtracting the synchronous sampling values to obtain;
Figure FDA00027086006300000420
and if the difference between the two phasors is equal to the third phasor, subtracting the synchronous sampling value of the two phasors by the synchronous sampling value of the third phasor, and applying to vector subtraction operation.
7. The phasor product active method for determining a faulty phase and selecting a line according to claim 2, characterized in that: the sampling value of the neutral point voltage is obtained by adding synchronous sampling values of three phases of voltage to ground according to the formula (2.1) or obtained by converting the sampling value of the open triangular voltage of the voltage transformer;
and if the sum of the two phasors is equal to the third phasor, adding the synchronous sampling values of the two phasors to the synchronous sampling value of the third phasor, and applying to vector addition operation.
8. The phasor product active method for determining a faulty phase and selecting a line according to claim 4, characterized in that: the line selection criterion is suitable for a power grid system with a neutral point resistor grounded.
9. The phasor product active method for determining a faulty phase and selecting a line according to claim 4, characterized in that: phasor setting
Figure FDA0002708600630000051
And phasor
Figure FDA0002708600630000052
The phasor product active power of is WE1*F1Phasors
Figure FDA0002708600630000053
And phasor
Figure FDA0002708600630000054
The phasor product active power of is WE2*F2；
If WE1*F1≥WE2*F2Then, there are:
Figure FDA0002708600630000055
or:
Figure FDA0002708600630000056
n1is a number of samples greater than half a cycle time period, uE1(ti)、uF1(ti)、uE2(ti) And uF2(ti) Are respectively as
Figure FDA0002708600630000057
And
Figure FDA0002708600630000058
at tiTime of dayOf the sampling value(s).
CN201910223581.8A 2019-03-22 2019-03-22 Phasor product active method for judging fault phase and selecting line Active CN109884471B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201910223581.8A CN109884471B (en) 2019-03-22 2019-03-22 Phasor product active method for judging fault phase and selecting line

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201910223581.8A CN109884471B (en) 2019-03-22 2019-03-22 Phasor product active method for judging fault phase and selecting line

Publications (2)

Publication Number Publication Date
CN109884471A CN109884471A (en) 2019-06-14
CN109884471B true CN109884471B (en) 2020-12-11

Family

ID=66933784

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201910223581.8A Active CN109884471B (en) 2019-03-22 2019-03-22 Phasor product active method for judging fault phase and selecting line

Country Status (1)

Country Link
CN (1) CN109884471B (en)

Citations (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN2245219Y (en) * 1994-05-06 1997-01-15 张海文 Electric transmission line single phase ground fault descrimination and selection line device
US5773980A (en) * 1997-01-30 1998-06-30 Abb Power T&D Company, Inc. One-terminal fault location system that corrects for fault resistance effects
CN1440102A (en) * 2003-01-09 2003-09-03 西安交通大学 High voltage circuit phase selection based on pallern identification
EP1089081A3 (en) * 1999-09-23 2003-12-03 ABB Substation Automation Oy Method for computational determination of ground fault distance in an electrical power distribution network having a ring configuration
CN1800867A (en) * 2005-12-23 2006-07-12 山东达驰电气股份有限公司 Single-phase earth fault line selection method for medium and low voltage distribution network
CN101368998A (en) * 2008-10-15 2009-02-18 中国矿业大学 Route selection method suitable for arc suppression coil earthing electric network
CN101369727A (en) * 2008-10-15 2009-02-18 中国矿业大学 Route selection method aiming at electric arc ground fault
CN103018630A (en) * 2012-11-28 2013-04-03 福建省电力有限公司 Single-phase earth fault transient line selection method of distribution network
CN103176106A (en) * 2013-03-01 2013-06-26 江苏镇安电力设备有限公司 Neutral conductor matching IT (information technology) system single-phase earth fault phase selection method
CN103529358A (en) * 2013-08-15 2014-01-22 国家电网公司 Method for detecting continuous high-impedance-grounded fault of medium-voltage distribution system by current information
CN103605039A (en) * 2013-09-18 2014-02-26 国家电网公司 Method used for detecting single-phase earth faults through current sequence signals
CN104730410A (en) * 2015-03-16 2015-06-24 王金泽 Distribution line breakage monitoring method and device based on voltage and current vectors
CN204462305U (en) * 2015-03-16 2015-07-08 王金泽 A kind of distribution line disconnection monitor based on electric current and voltage vector
CN104777397A (en) * 2015-04-16 2015-07-15 王金泽 Distribution line single-phase break line judgment and positioning method based on line voltage vector criterion
CN106501668A (en) * 2016-03-16 2017-03-15 济南大学 A kind of conventional electrical distribution net single-phase wire break fault-line selecting method
KR20170031564A (en) * 2015-09-11 2017-03-21 한국전력공사 Apparatus and method detecting direction of fault current
CN107064728A (en) * 2016-09-26 2017-08-18 国网甘肃省电力公司电力科学研究院 The single-ended holographic frequency domain Fault Locating Method of ultra-high-tension power transmission line
CN107179466A (en) * 2017-04-21 2017-09-19 国网江苏省电力公司镇江供电公司 The fault line selection method for single-phase-to-ground fault of small current neutral grounding system

Patent Citations (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN2245219Y (en) * 1994-05-06 1997-01-15 张海文 Electric transmission line single phase ground fault descrimination and selection line device
US5773980A (en) * 1997-01-30 1998-06-30 Abb Power T&D Company, Inc. One-terminal fault location system that corrects for fault resistance effects
EP1089081A3 (en) * 1999-09-23 2003-12-03 ABB Substation Automation Oy Method for computational determination of ground fault distance in an electrical power distribution network having a ring configuration
CN1440102A (en) * 2003-01-09 2003-09-03 西安交通大学 High voltage circuit phase selection based on pallern identification
CN1800867A (en) * 2005-12-23 2006-07-12 山东达驰电气股份有限公司 Single-phase earth fault line selection method for medium and low voltage distribution network
CN101368998A (en) * 2008-10-15 2009-02-18 中国矿业大学 Route selection method suitable for arc suppression coil earthing electric network
CN101369727A (en) * 2008-10-15 2009-02-18 中国矿业大学 Route selection method aiming at electric arc ground fault
CN103018630A (en) * 2012-11-28 2013-04-03 福建省电力有限公司 Single-phase earth fault transient line selection method of distribution network
CN103176106A (en) * 2013-03-01 2013-06-26 江苏镇安电力设备有限公司 Neutral conductor matching IT (information technology) system single-phase earth fault phase selection method
CN103529358A (en) * 2013-08-15 2014-01-22 国家电网公司 Method for detecting continuous high-impedance-grounded fault of medium-voltage distribution system by current information
CN103605039A (en) * 2013-09-18 2014-02-26 国家电网公司 Method used for detecting single-phase earth faults through current sequence signals
CN104730410A (en) * 2015-03-16 2015-06-24 王金泽 Distribution line breakage monitoring method and device based on voltage and current vectors
CN204462305U (en) * 2015-03-16 2015-07-08 王金泽 A kind of distribution line disconnection monitor based on electric current and voltage vector
CN104777397A (en) * 2015-04-16 2015-07-15 王金泽 Distribution line single-phase break line judgment and positioning method based on line voltage vector criterion
KR20170031564A (en) * 2015-09-11 2017-03-21 한국전력공사 Apparatus and method detecting direction of fault current
CN106501668A (en) * 2016-03-16 2017-03-15 济南大学 A kind of conventional electrical distribution net single-phase wire break fault-line selecting method
CN107064728A (en) * 2016-09-26 2017-08-18 国网甘肃省电力公司电力科学研究院 The single-ended holographic frequency domain Fault Locating Method of ultra-high-tension power transmission line
CN107179466A (en) * 2017-04-21 2017-09-19 国网江苏省电力公司镇江供电公司 The fault line selection method for single-phase-to-ground fault of small current neutral grounding system

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
基于五次谐波电流变化特征的单相接地故障选线方法;刘兴艳 等;《电子质量》;20101231(第03期);第35-37页 *

Also Published As

Publication number Publication date
CN109884471A (en) 2019-06-14

Similar Documents

Publication Publication Date Title
Dāsa Determining the locations of faults in distribution systems
Das et al. Transmission line fault detection and location using wide area measurements
WO1995024014A2 (en) One-terminal data fault location system
Zadeh et al. Phasor measurement unit based transmission line protection scheme design
Lee et al. A new two-terminal numerical algorithm for fault location, distance protection, and arcing fault recognition
CN103197203A (en) Fault line selection method based on time domain waveform correlation analysis of three-phase current breaking variable
CN104764978A (en) Single-phase earth fault phase selection and transition resistance measurement method
Xu et al. Ground distance relaying algorithm for high resistance fault
Gajare et al. Synchrophasor-based intelligent autoreclosing scheme for series compensated transmission lines
Junior et al. Fault location in series-compensated transmission lines based on heuristic method
CN114184843A (en) Method and apparatus for estimating source impedance on one or more transmission lines
Batista et al. Methodology for information extraction from oscillograms and its application for high-impedance faults analysis
Wen et al. Equal transfer processes-based distance protection of EHV transmission lines
Paul et al. Fault detection and classification scheme for smart grids considering high impedance evolving and cross-country faults
CN110024249B (en) Method for detecting a fault in an electric power transmission line and protection system using the method
CN109884471B (en) Phasor product active method for judging fault phase and selecting line
CN109782114B (en) Method and system for judging full-compensation ground fault state of controllable voltage source
Ren et al. Research on the countermeasures of the single-phase-to-earth faults in flexibly grounded distribution networks
EP3971592A1 (en) Fault location determination in a power transmission system
Nam et al. Ground-fault location algorithm for ungrounded radial distribution systems
Gorgani Firouzjah Fault Location on Compensated Transmission Lines without Current Measurement
Ma et al. Faulty phase recognition method for single-line-to-ground fault in resonant grounded distribution networks
Sun et al. Fault location analysis of ungrounded distribution system based on residual voltage distribution
Xu et al. Faulty line selection based on active-intervention-type arc suppression device via additional neutral resistance
Anierobi et al. Review of Impedance-Based Fault Location Algorithm in Electric Power Transmission Line, using computerized fault recorders.

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant
EE01 Entry into force of recordation of patent licensing contract

Application publication date: 20190614

Assignee: HEFEI YIXIN ELECTRIC POWER TECHNOLOGY Co.,Ltd.

Assignor: Zhang Anbin

Contract record no.: X2021340000010

Denomination of invention: Fault phase identification and line selection by phasor product power method

Granted publication date: 20201211

License type: Common License

Record date: 20210525

EE01 Entry into force of recordation of patent licensing contract
TR01 Transfer of patent right

Effective date of registration: 20221017

Address after: 230601 Areas B and C, Floor 5, A3 #, Phase II, Industrial Investment Liheng Industrial Plaza, at the intersection of Fanhua West Road and Chuangxin Avenue, Taohua Industrial Park, Hefei Economic Development Zone, Anhui Province

Patentee after: HEFEI YIXIN ELECTRIC POWER TECHNOLOGY Co.,Ltd.

Address before: 230022 room 1, building 122, No. 107, Jinzhai Road, Hefei, Anhui

Patentee before: Zhang Anbin

TR01 Transfer of patent right