JPH01228207A - Digital filter for negative-phase-sequence component - Google Patents

Abstract

PURPOSE:To remarkably reduce the error ratio of a positive-phasesequence component in case of fluctuating a frequency by using a digital type filter of negative-phase-sequence component consisting of a data acquiring device and a processor. CONSTITUTION:The quantities of electricity Ea, Eb, and Ec of each phase in a three-phase power system are inputted by a data acquring means 1, and those quantities are sampled by the cycle of a frequency of natural number times the rated frequency of the power system, and sampled values are converted to digital data (shown in D comprehensively). First and second negative-phase sequence component data D1 and D2 from negative-phase-sequence component calculation means 2 and 3 are synthesized by a synthesis means 4, then, a third negative-phase-sequence component data Dn shown in following equation is calculated. In other words, the data Dn found by equation of Dn=K1D1+K2D2 (where, K1 and K2 express the constants of real numbers) is used in the protective arithmetic operation of a protective relay device, etc. In such a way, it is possible to improve the error ratio of the positive-phase-sequence component remarkably, and to improve it in case of generating the fluctuation of a wattmeter and the frequency by 5% to around less than 0.1%.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a negative phase digital filter used in a protective relay device of a power system, etc. (Prior art) Short circuit in a three-phase power system Alternatively, a protective relay device that uses the amount of electricity (voltage or current) for the opposite phase is used to prevent ground faults. The purpose of this is to detect faults with a much higher sensitivity than general relays such as distance relays in the event of high-resistance ground faults such as water contact or remote faults.

A digital relay is provided which calculates negative phase electricity quantity data from sample values of electricity quantities of each of the three phases and uses this data for protection.

(Problem to be solved by the invention) In conventional devices, the frequency error generated by the positive-sequence component of the input electrical quantity is large, and when the rated positive-sequence electrical quantity is added, the negative-sequence electrical quantity of the rated value of the error output ( (hereinafter referred to as the rated negative sequence electricity quantity)
The ratio (hereinafter referred to as positive-sequence error ratio) to the output (hereinafter referred to as rated negative-phase output) when J [J[J] is exceeded reaches approximately 3% when the power system frequency changes by 5%.

Although this value does not seem to be very large, there are many cases where a reverse-phase relay needs to respond even to a negative-sequence amount of electricity of around 1% of the rated negative-sequence amount of electricity, and in such cases, the above-mentioned 3. With a positive-sequence error ratio of %, protection ability cannot be exhibited when two frequencies fluctuate.

An object of the present invention is to significantly improve the positive phase component error ratio.

It is an object of the present invention to provide a digital type anti-phase valve filter that can improve the positive phase error ratio to about 0.1% or less when the wave number of the power meter and the stone layer changes by 5%.

[Configuration of the Invention] (Means for Solving the Problem) FIG. 1 shows the configuration of the present invention. In the figure, 1 is after data (indicated by E when grouped), these are sampled at a frequency frequency that is a natural number multiple (for example, 12 times) of the power grid rated frequency, and the sampled values are converted into digital data ( - collectively indicated by D). Reference numerals 2 and 3 are reverse phase valve data calculation means that calculate first and second reverse phase valve data D and D2, respectively. 4 is a synthesizing means that synthesizes the reverse phase valve data D1 and D2 to calculate third reverse phase valve data [)n expressed by a quadratic equation.

Do=1D1+K2D2・・・・・・・・・・・・・
...(1) (However, 1 and 2 are real constants) This data D. is used for protection calculations of protective relay devices, etc.

In FIG. 1, for convenience of explanation, data Dn is calculated after calculating data D1 and D2.
It is possible to calculate the composite data D of equation (1) without calculating the data D1 and D2.

Data D1 and D2 are data similar to those calculated by a conventional reverse phase valve data calculation means, and are necessarily expressed by a linear equation as a composite value of data at at least two different sample times of data D.

11D11+K12D12+(K13D13) to DI-
......(2) [)2-21D21+K22D22+(K13DI3
)...(3) IUl, K11, K12, K13, K21, K22 and 23 are real constants, D11, DI2, DI3, D2
1, D22 and D23 are the time t11, t12, shi, 3, t21, the pulled data or the composite value of the data, respectively. The selection of times 111 to t23 will be explained. Here, consider the quantity of electricity -1 and white 2 in the following equation.

・j(1+Y)θ72 El = 11E11+K12E12” +
・j(1+Y)073 (K13E 13ε) ・・・・・・
...(4)・j(1+Y)θ22 21E21+K22E22""+ to E2-
・j(1+Y)θ23〈K23E23ε〉 ・・・・・・・・・
...(5) (However, θ12, θ13, θ22, and 0
23 is the difference in sample time t12 ``11, t13, respectively.
−111, t22−121, and t23 “21 are values expressed in electrical angles at the power system rated frequency, for example, t
12 "11 is positive if t12 is later than January. Also, Y is the frequency fluctuation rate of electricity ff1E, which is expressed by the following formula.〉7-Frequency of electricity quantity E -1--------
'-(6) Rated frequency of the power system The electric quantity 1 to 123, the constant 11 to 23, and the sample time difference 012 to θ23 are the frequency fluctuation rate Y
When is zero, the electric quantity 1 of equations (lI) and (5)
(T> and r2 are both negative phase meters of electric mill.

(similar to normal anti-phase component calculation means) so that it is proportional to only At this time, electric quantity mill 1 and ρ
2 is expressed by the following formula.

White, - good. Puppy, -・-・-... (7) White, -Good. To 2...<S) (However, K and '5
□2 is a complex constant. As a result of the above, when the electric quantity "is only the positive phase component, and considering the case where the frequency fluctuation rate Y is not zero,
It is expressed by electric quantity mill and #, , +, linear expression.

(However, f, 1 and f, 2 are each a function of Y, and Y = 0
When , the value also becomes zero. ) The difference between sample time t11 and ``21, J, and the constant 5 in equation (1) and call are the functions E and f, 2 in equation (9), J, and (10), as shown in the following equation. determined.

2 Jθ21. f ε −pl ・・・・・・・・・(11) Kl
fp2 (however, θ21 is the value expressed by the electrical angle of the power system rated frequency, which is the time t21-111 during which the sample time t21 lags tll), but even under the above conditions, Kjθ27. 2.5 -nl ・・・・・・・・・(12)K
1 Kn2 later are excluded.

(Operation) First, the relationship between equations (2) and (4) will be explained. (2
) The data D12 of the formula is the sample part of the data D11 ) time t
This data is sampled at a time delayed by 012 in electrical angle of the power system rated frequency from 11.

This delay can be expressed as an electrical angle at the frequency of the electric quantity P (1+
Y) θ12. It is equal to data obtained by sampling the quantity of electricity ρ12 at time t12, which is delayed from time t11 by (1+Y)012 in electrical angle.

From the above, the data D1 of equation (2) is the electricity of equation (4)! line
When 4. +J tll is equal to one sample of data. Similarly, data D2 of equation (3) is obtained by lean-pulling the electrical quantity ρ2 of equation (5) at time t21, n:y
It is equal to the data sampled at t11.

Therefore, data D in equation (1). is the following equation for electricity...
...... (14) Under the condition that the frequency fluctuation rate Y or zero, it is proportional to (4), so it is an electric quantity mill. is Ee −KI KnlEn ”'2 Kn2En ・”
”jθ21 ・−(K K +K K ε )Eol
nl 2 n2 (15)

As described above, under the condition of Y=0, data D. are not compatible. Therefore, the data corner becomes the output data of the negative phase gain filter. If the electric quantity mill does not include a negative phase component, 1° in equation (15) is zero, so data is D. is always zero even if the sample time is .

Next, the frequency error, which is the main focus of the present invention, will be explained.

When the frequency fluctuation rate Y is not zero, the electric quantities 1 and 1 produce errors in equations (7) and (8). This error can be divided into the following three types.

Negative phase division difference: An error proportional to the negative phase differential The protective relay device that responds to the negative phase valve uses the negative phase valve when the positive phase component of the electrical quantity E is large and the zero phase component is small. The purpose is to respond with high sensitivity.

In such a case, the influence of the positive phase error is significantly greater than the square error, and the purpose of the present invention is to reduce the positive phase error, so the effect of reducing the positive phase error will be explained.

The positive phase errors of the electricity meter and white are expressed by equations (9) and (10), respectively. The function of frequency fluctuation rate Y and (
When expressed by equation (10), the positive phase error in equation (14) is: Le = +:, , Fi, + K2'4. Door, εXl+
y)o,.

Since 1, K2, and θ21 in equation (16) are selected based on the relationship in (11), E8 in equation (16) becomes. Here, compared to the conventional anti-phase valve digital filter whose data is the () - sample value which normally takes PJ into consideration for the frequency fluctuation rate Y, the positive phase error is significantly smaller.
When is zero, the negative phase component output of the electrical quantity 6 can be expressed as (20) from equation (15), or as K1, K2 and θ21 Rikiken12) and equation In this case, the combination U of 1 d3 and E2, which meets this condition, is not used.

Such a silk combination is expressed by equations (4) and (5).
In the formula, knl=Kn2, and (9) and (10), f, 1=r, and so on. From this condition, ・Reduce the positive phase error of electricity # rib e. ・However, 'nl/
Since Kn2 is also -1, equation (12) is established, and the reverse phase output of the electricity meter is also lost, making it unusable.

(Example) A first embodiment of the present invention will be explained using the drawings.

FIG. 2 shows one implementation of the hardware configuration of the present invention (511
In the figure, 5 is a data storage device and 6 is a processing device. The data acquisition 1q device 5 has three-phase alternating current a and b.

C Electricity of each phase fiiE8. Eb and self. are input, these are sampled at a period 12 times the rated frequency, and each of the 1-numbered shifts is converted into digital data Da.

Db OJ, biri. Convert to The processing device 6 performs dotted line processing using this digital data to calculate reverse phase valve data D. The processing device 6 also processes this data D. In some cases, without outputting the data to the outside, the data D, J: and other data are used to perform the suspension of the relay power supply, and a signal based on the result is output. The configuration 4111 shown in FIG. 2 is exactly the same as a generally used digital operation type protective relay device, so a detailed explanation will be omitted for the sake of brevity.

Next, the processing of this embodiment will be explained. In this embodiment, data D11. of equations (2) and (3). D12. D21 and D
22, the difference in number times shown in relation to each of these data, equations (4), (5), and (11) expressed in electrical angle at the rated frequency, and (1), (2) ,(3
) The constants in the formula are as follows.

Dll-Do-Da, D12-Da-Db.

D21-Da-Db, D22-Db-Do.

012=022-021"'-6°°・Kl ""K2
- to 11 = to 12 = to 21""K22-1...
(24) First of all, i3L is based on what is shown in equation (24) or stated in (means for solving the problem), so (4>(r'3 and (5) (25) and (26> Show each term in the equation by symmetrically dividing it.)

These are the positive phase component, the negative phase force, Jζ, and the zero phase component.

Because it is necessary, becomes.

From the equation (28), the electric quantities of the equations (25)d3 and (26) are obtained.

In addition, electricity 11Fi E and 1 when there is only electricity fj E or negative phase force [E n, and the frequency fluctuation rate Y is zero
Value of 2 Eln and wall? , is as follows.

11□-3F:,” ・・・・・・・・・(33
) [2n-3En band ・・・・・・・・・(3
4) From (29) and Equation (30), the value of the function of Equation (9) and (10) is f pl "-" 2 J 3 S l nY30°-
120'-Y30'...--(,Y5)f,
2=2 J35inY30°mu120'-Y30'
・Old--(B6) becomes f, 1 and f, 2
is zero for Y=O, and 1. in equation (24). The values of 2, J, and θ21 are based on equation (37).

Also, the constant K and fortune in equations (7) and (8) are (33>
, From formula (34), Kn1=31 shift γ ・・・・・・・・・(38)
K, 2=3 (39
)...(/IO) Therefore, clause 1'[ of equation (12) is satisfied -1.

The above J is based on the formula (24) (sl (means for solving the problem)).

Next, the specific processing procedure of this embodiment will be explained with reference to the drawings. FIG. 3 is a flow diagram showing data processing in this embodiment. When processing starts, processing L'I! 7teDalTl
, DbIll and Ri. Obtain and store 1°. Subsequently, after performing the quick burial 8 prediction ((1100 calculations, 19 data D calculations, and updating the data in process 10), the process returns to process 7.

In process 8, the following data D"cam and cm Calculate Dabm.

In process 10, the data that has been written down is recorded as follows.

vinegar. aIIl, UablTlAyohi (2il U notator LJ nm'? IL! It is expressed as a mountain.

) That is, data Dh1D(m-1), D(m-1)
is the data sampled 30 degrees ago.

In process 9, data Dnm is calculated and recorded using the following equation.

Dnm=Dcam "2Dab(m-2)" D
-... (Ki) bc (m 4) The iris obtained from this wavy line, IIl is each data.

It is equal to the latest sample value of data D in equation (1) when the difference between the constant and sample time is expressed as equation (24).

Next, the special functions of this embodiment will be explained. data [], is (14
It is equal to the ripple value of the electric suspension shown in the equation. In this embodiment, each constant value in equation (14) is 1""'2-'1. θ
−−60°, the electric quantities “1” and “ρ2” are each (2
Equations (9) and (30) are shown below.

Rewriting equations (2) and (30), +31nuni+311mutuni+2J3sinY30'Enyu20'-Y30'
・(36)+Ena 暉二連W) + 2 J'35inY30°(-に厘+3J3E, l
When Y=O, equation (37) becomes the rated reverse phase output.

The error proportional to the negative phase component l is calculated.

, and when the frequency fluctuation rate Y is 0.05, E −4
J'3×0.02622F pp -〇,000686x 4 J3 E, ・(
40).

In this case, the positive phase division ratio K/ratio (the ratio of the error output to the rated negative phase output when the rated positive sequence electricity quantity is added) Gp is as follows.

The magnitude of the error Ego proportional to the negative phase component is E gn”F
6 E n S:n Y30' ・Old・Dan・
(42), and when Y = 0.05, E, -6X0.0262En...old-(43)
Then, the correct negative phase output size F of this value is.

The ratio (hereinafter referred to as negative phase division difference ratio) Gn to (absolute value of equation (38)) is as follows.

The conventional device, for example, obtains the non-pull value of the electrical quantity 11 in equation (35), and when Y=O, F1=3E, and the value is (45).

Y-/! When =O, the magnitude of the positive phase error Fgo is E
=2J3sinY30°[E, −・・−・・
-・(46)D, and when y=o, 05, E=0.0262X2J3E, ...
...(47)p. In this case, the positive phase error ratio G is as follows.

The value of the positive phase error ratio G of this embodiment shown in equation (41) of 0.092% is 3.03%, which is the value of equation (/18) of the conventional device.
It's quite small compared to the percentage. This effect is due to the opposite phase [
This can be easily understood by considering the case where E = 0.05F, for example, when the size of the positive phase component is significantly smaller than .
7ru. In this case, the conversion of the magnitude of the 1-minute error output to the correct negative phase output is G.

= 3.03% reaches 6056%, or G, -0,0
92%-c tit:, only 1.8/I%.

Incidentally, since the negative phase division difference ratio of 3.03% in this embodiment is the correct negative phase component output or 100%, there is generally only one subpupil.

In addition, in this example, each constant was set as shown in equation (24), or
Let each constant be 11 = 21 ='l, 2; K11KK
K K12 K22 KI K21
Regarding other values in the relationship, the only difference is the number of threads on the right side of data D, , D1 and D2 in formulas (1), (2) 83 and (3), and each article of incorporation is changed to (24> The same effect as in the case of formula 41 is obtained.

A second embodiment of the invention will be described. The second embodiment is similar to the first
The only difference from the embodiment shown in FIG. 3 is the processing contents of processes 8.9 and 10 in FIG. 3, so only these different parts will be explained.

For lost burial 8, the following data D, DbolTl and 80m Calculate and store DooIII.

Process 10 performs the same updating as in the first embodiment except that the contents of the stored data group are different.

In process 9, data DnIII is calculated using the following formula and recorded.
50) nm con ao (m2)
bo(m 4) This calculated value is a value showing the difference in sample tenses at the rated frequency, and each data Jζ and each constant of equations (1), (2), and (3) are as follows.

Dll-Do-Do, D12-Da-Do.

[]]2l-Da-Do, D22-DbDo.

Equation (51) will be explained. Day 9D,,,Db.

D a3 yo UD c each electric mF, Eb, L
o<r3J:c o a
Bison's zero phase [. Since the data is υcombined, (
The armatures r1, J, and ρ2 in equations 4) and (5) are as follows.

...(52) E2-Ea Eo+(E=6 Lo) L1 Nido Shioka W2...(53) From the relationship of equation (27), Go - Daijiri gu + 100 H 芒■pu + Mortar rl IP with B+End Sakudomari
P...(54)...(55).

From equations (56) and (59), (9) and (10)
The value of the function of Eq. These values are zero when Y=O, and are always (1
1) In the formula, 2 h −J3+= , −1j ... (62) 1
fp2, and 1. 2 and θ21 are based on 7%F in equation (37).

Also, the constants in equations (7) and (8) are (58) and (5
9) Better than Eq. 1=J-3L×W2, k02 becomes 1, so the condition of equation (12) does not hold.

The above J:Uni formula (51) is based on the matters mentioned in (Means for solving the problem).

Next, the positive phase component error ratio of this embodiment will be explained. In this example, each constant in equation (14) is 1-2-1021--6
0°, and the positive phase error output of the electricity meter due to the positive values of m3 and r2 is as follows.

ra, =2 s1n'Y3gu(tpmunogu〉gu・to,Pgusasoge)-"4 s in'Y'30'E
bA "I α Ri... (64) Also, the value of the quantity of electricity 1 in the case of Y=O is as follows from equations (14), (58), and (59) and the function of the above constant.

The positive phase component error ratio sieve is (64) and (65
) From the value of the coefficient of the equation, the following is obtained, and in the case of Y=0.05, the following is obtained, and the effects of the first embodiment and lTi1 are demonstrated.

In this example, each constant is set as shown in equation (51), or each constant is set as a value in the relationship of (1>, (2), and (1>, (2), and
3) Only the total number of threads in the data corner of the equation and the right side of Dl and D2 is changed, and the same effect is obtained.

Regarding the third example, differences from the first example will be explained. This embodiment differs from the first embodiment only in the processing contents of processes 8.9 and 10.

In process 8, data DboIIl, Doa of equation (32)
lTld3 and 0ab11. and data DaolTl of equation (49).

DboIIl OJ, biri. Memorize om. Process 10'c (Well, data 11 is updated in the same way as in the first embodiment, except that the stored data JSY is different.

In process 9, the data corner □ is calculated using the following formula and recorded as IQ.

Zuru.

D=D+2J3Dao(m-1) -Dab(m-2)
nm can ... (68) This output value is the value showing the difference between samples 15'1 and 15'1 at the rated frequency, each data d5 of formulas (1), (2), and (3) and each constant. Formula (69) should be used.

Dll-Do-Da, D12-Da-D. .

D21-Da-Do, D22-Db-Da.

Let me explain the formula (69). Under the condition of equation (69), r
−ρ+J3 <white. -White. )Dan Kyo Kasa 1 ca... (71) From the relationship of (27) and (28), 1-JΣ (White P encouragement ° ten pieces, Yo + song. bze・Jin, L takubei 4 ni) , , (72) E = 2 J 3 'L
5inY15°-120'-Y15' ・(74)i
p , p E 2p-2J 3 E p s+nY15° 90'
-Y15'-(75)I:1. =#, 3t::. Yoe ・・・・・・・・・(76) Self 2゜−J3
ρ, melonr ・・・・・・・・・(77)(7
/l ) and (75), (9) ib and (1
0) The value of the function of equation is. These values are zero when Y=O, and (1
1) In the formula, .

, and 1 in equation (69). 2 and 11 white of θ21 and 1 (37).

Also, the constants in equations (7) and (8) are (76) and (7
From equation 7), Kn1=J3[K02 K1, which does not satisfy the condition of equation (12).

As described above, the conditions of formula (69) comply with the matters described in (Means for Solving the Problem).

Next, the positive phase error ratio of this embodiment will be explained. This implementation 1 sill
Then, each constant in equation (14) becomes 2 = 1°.

Auto -2J55inY15° (white pb Goki Gago late minister 20 E(-i)lP- Also, the electricity meter in the case of Y-O(7).The value of is (14),
The relationship between equations (76) and (77) and the constants is as follows.

−J3ρ. 5 degrees...(83) The former positive phase error ratio G is (82) and ゛(83)
From the number of threads in the formula, if Y = O505, G = 4x0.01312 = 0.069%...
...(85), which has a slightly better effect than the first and second embodiments.

In this example, each constant is set as shown in equation (69), but each constant can also be expressed as a value of the ratio having the relationship of 11 K22 KI K22, (1), (2), and (
3) The only difference is the number of threads of Ishibe's rest in the data D, D1, and D2 of the equations, and the same effect as when each constant is set to the equation (69) is obtained.

The phase j hill point of the fourth embodiment with respect to the first embodiment will be explained. This embodiment differs from the first embodiment in the process 1 in FIG.
! ! ! 8 is omitted, and the processing content of processing 9 and 1o is 5.
It is the same except that it becomes In process 1, the data group is updated in the same manner as in the first embodiment, except that the stored data group is different.

In process 9, the data group DnlTl is extracted and stored using the following equation.

The data and constants of equations (1), (2), and (3) shown in (1), (2), and (3) are as follows.

Dll-DC・D12-“a-D13-Db・K1-1
．． 2 = 2 (87) (
87) Expression will be explained. According to equation (87), (1)
Latest calculated data D of formula data D. lTl is as follows.

Dnm"" D1m+2D2(m-2) ""
...(88) Calculated data D11 used in the data corner □ of data D1 and D2 of formulas (2) and (3)
Substituting Il and equations (89) and (90) into equation (88) yields equation (86).

Under the conditions of Equation (87), the electric quantities white, J: and K of Equations (4) and (5) become as follows.

11-White. 10 [am + Y) 12 kaku + Eb a shi μμ work... (91) White, -white. +6 = knee-1゜b -μm20'...(92〉) From the relationship in equation (27), = (5=nY12o°+2s*%Y6Q door p□4-±
? Mi2nee YIZ (do 1.-('t's) white) P=
(-1q+ 1-1d) 100r Otsu-60"-γUp=(-
,1"5 s'tnY%o'+ 2 sln"Y3D
°I, h-en! -The value of the function of equation (3G) is TFI = (5s'+nYI20', 25*n: Y
%O") l =-ζtutu)'+ 2 = C-E 5
inY6D°ya2 sIN Y2O")l --, (
1oo). These values are zero when Y=O,
The ratio of both functions is as follows under the condition that Y is about O11 or less.
- In equation (87), 1, K2, and θ21 are based on equation (37).

Also, each constant in equations (7) and (8) is (97) and U (
98) Shikiyoyou. 1=3bgar, good n2=31. Since z, the following holds true, and the condition of equation (12) is satisfied.

The above condition of formula (87) must comply with the small matter (means for solving the problem).

Next, the positive phase error ratio of this embodiment will be explained.

Each constant in equation (14) is K1-! , K2-2, θ21(
96), the following is obtained.

E, e = Cf':3s;nY12Q''+2xin2
Y et O”-255=YbD”+4 S i8”T”30
- White, L 2 history 20 poems = r2 f”r 5inY6
Q' (1-2s rn"Y3o') + 2sin
'Ybo'-zf3 s'+nY o'+4-sirt
7Y3Q') E, d , , -4+o+) sir
t"ygO°==4Sln2Y30"cos2Y3o"
= Cow sin"Y3o"4s'+n" Y3°.

From the relationship, equation (104) is = (t", s 1rrYmu o' -2s m" Y31
1) "f door, a2 Z'O"-Y 720" ・=
(It becomes loj l.

Mata, the value of the quantity of electricity in the case of Y=0 is (14〉, (9
7> and the relationship between equation (98) and the above constants are as follows.

White. =3ra/, d120'+6 houses. △That knee 9 and others are written...(106)...(1
07) (107), which is the case where Y = 0.05, and the same effect as the first embodiment is obtained.

In this example, each constant is set as shown in equation (87), but each constant can also be set to other values in the relationship (1), (2) a3 yo (3) equation 0 , Dl and D2 (only the overall coefficients of the T side change, producing a similar effect.

[Effects of the Invention] As explained above, according to the present invention, it is possible to realize a negative phase digital filter in which the positive phase component error silence ratio when the frequency fluctuates is significantly reduced.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing the configuration of the negative phase digital filter according to the present invention, Fig. 2 is a block diagram showing the !M configuration of the hardware of an embodiment of the present invention, and Fig. 3
A flowchart showing the data summary of the present invention is shown below. 1... Data acquisition means, 2, 3... Negative phase component calculation means 4... Synthesis means, 5... Data acquisition means. 1 ■ Device, 6
...Processing equipment, 7...Data acquisition, embedding, 8...
・Preliminary (+ii+ calculation process, 9... Reverse phase data calculation process, 10... Data update process

Claims (5)

[Claims] (1) Electricity amount (voltage or current) of each phase of a three-phase power system■
a first means for obtaining digital data by sampling it at a frequency frequency that is a natural number multiple of the rated frequency of the power system; a second means for calculating data D_n=K_1D_1+K_2D_2 (where K_1 and K_2 are constants of real numbers), which is a combination of the first negative phase data D_1 of quantity ■ and a different second negative phase data D_2; The first and second negative phase data D_1 and D
Each _2 is a composite value of data at at least two different sample times shown in the following formula, D_1=K_1_1D_1_1+K_1_2D_1_2
+(K_1_3D_1_3+...)D_2=K_2_
1D_2_1+K_2_2D_2_2+(K_2_3D
_2_3+...) (However, K_1_1, K_1_2,
K_1_3, K_2_1, K_2_2 and K_2_3
are real constants, D_1_1, D_1_2, D_1_3,
D_2_1, D_2_2, and D_2_3 are each at time t_1
_1, t_1_2, t_1_3, t_2_1, t_2_
2 and t_2_3 have electrical quantities ■_1_1, ■_1_2,
■_1_3, ■_2_1, ■_2_2 and ■_2_3
) and the constants K_1_1, K
_1_2, (K_1_3...), K_2_1, K_2
_2, (K_2_3...) are electric quantities ■_1 and ■_
When 2 is expressed as the following formula, ■_1=K_1_1■_1_1+K_1_2■_1_2
ε^j^(^1^+^Y^)^θ^1^2+(K_1_
3■_1_3ε^j^(^1^+^Y^)^θ^1^3
+...)■_2=K_2_1■_2_1+K_2_2
■_2_2ε^j^(^1^+^Y^)^θ^2^2+
(K_2_3■_2_3ε^j^(^1^+^Y^)^
θ^2^3+...) (However, θ_1_2 and θ_1
_3 are the sample time differences t_1_2-t_1_1 and t_1_3-t_1_1, θ_2_2 and θ_2, respectively.
_3 is a value representing the sample time difference t_2_2-t_2_1 and t_2_3-t_2_1 in electrical angle of the rated frequency of the power system, for example, t_1_2-t_1_1
is positive if t_1_2 lags behind t_1_1. Further, Y is Y=frequency of electric quantity (■)/rated frequency of power system-1. ) If the quantity of electricity ■ is only the negative phase component ■_n and Y=0, then ■_1=
■_n_1 ■_n and ■_2 = ■_n_2 ■_n (however, ■_n_1 and ■_n_2 are complex constants other than zero), and if the electric quantity ■ is only the positive phase component ■_p, then ■_1 = ■_p_1 ■_p and ■＿２＝■＿p＿２■
_p (where ■_p_1 and ■_p_2 are each a function of Y that becomes zero when Y=0), and the constants K_1, K_2 and the difference between sample times θ_2
An anti-phase digital filter characterized in that _1 is set to ▲There are mathematical formulas, chemical formulas, tables, etc.▼, and ▲There are mathematical formulas, chemical formulas, tables, etc.▼. (2) The amount of electricity of each of the three phases in order of positive phase, respectively ■_a, ■_
b, ■_c, data D_1_1, D_1_2,
D_2_1 and D_2_2 are each electric quantity ■_c−■_
a, ■_a-■_b, ■_a-■_b and ■_b-■
It is a sample value of _c, and the relationship between each constant is K_1_1/K
_1_2=K_2_1/K_2_2, K_2/K_1=
K_1_1/K_2_1, and data D_1_
2. The negative phase component digital filter according to claim 1, wherein sample times of data D_2_1 and D_2_2 are respectively 60 degrees, 60 degrees and 120 degrees before the sample time of data D_1_1 at the power system rated frequency. (3) Electrical quantities of each of the three phases in order of positive phase, respectively ■_a, ■_
b, ■_c, data D_1_1, D_1_2,
D_2_1 and D_2_2 are electric quantities ■_c and ■_
These are the sample values of the electrical quantities obtained by removing the zero-phase component from each of a, ■_a, and ■_b, and the relationship between each constant is K_1_1/K_1_2=K_2_1/K_2_1, K
_2/K_1=K_1_1/K_2_1, and the sample times of data D_1_2, D_2_1, and D_2_2 are 60 degrees, 60 degrees, and 120 degrees earlier than the sample time of data D_1_1, respectively, at the power system rated frequency. The negative phase digital filter according to claim 1. (4) Electrical quantities of each of the three phases in order of positive phase, respectively ■_a, ■_
b, ■_c, data D_1_1, D_1_2
, D_2_1 and D_2_2 are each electric quantity ■_c−■
_a, the quantity of electricity obtained by removing the zero phase component from ■_a, the quantity of electricity obtained by removing the zero phase component from ■_a, and ■_b - ■_a, and the relationship between each constant is K_1_2/K_1_1=K_2_1/K
_2_2=√3, K_2/K_1=K_1_1/K_2
_2, and the sample times of the data D_1_2, D_2_1 and D_2_2 are respectively 30°, 30° and 60° earlier than the sample time of the data D_1_1 at the power system rated frequency. minute digital filter. (5) The amount of electricity of each of the three phases in order of positive phase, respectively ■_a, ■_
b, ■_c, data D_1_1, D_1_2
, D_1_3D_2_1, D_2_2 and D_2_3
are the electrical quantities ■_c, ■_a, ■_b, ■_b, ■_a, respectively.
, ■_c, and the relationship between each constant is K_1_1:K_1_
2:K_1_3=1:1:1, K_2_1:K_2_2
:K_2_3=-1:1:-1, K_2/K_1=2K
_1_2/K_2_2, and data D_1_2,
D_1_3, D_2_1, D_2_2 and D_2_3
2. The negative phase component digital filter according to claim 1, wherein the sampling times of the data D_1_1 are 120°, 240°, 60°, 120°, and 180° earlier than the sampling time of the data D_1_1, respectively, at the power system rated frequency.