JP6546026B2 - Apparatus for eliminating different frequency and method thereof - Google Patents

Description

  Embodiments of the present invention relate to a different frequency removing apparatus and method for removing different frequency components superimposed on any power supply frequency.

  In an AC transmission line, transmission lines of power supply frequencies different in frequency from each other may be present in close proximity. Specifically, a transmission line in which 50 Hz flows and a transmission line in which 60 Hz flows may be closely embedded in parallel, or may be parallelly paralleled to the same steel tower. One power supply frequency is referred to as the relevant frequency, and the other power supply frequency is referred to as the different frequency in view of the relevant frequency.

  In the different frequency and the parallel line of the frequency, electromagnetic induction occurs mutually through the mutual inductance according to the separation and the parallel distance and the ground inductance. That is, the different frequency and the parallel line of the said frequency receive from each other the electromagnetic induction of the zero phase component according to the unbalance part of three phase permeability. The induced current circulates in the parallel loop transmission line at maximum when the transmission line on the receiving side is operated in the parallel loop.

  For this reason, in the parallel line of the different frequency and the relevant frequency, the induced circulating current due to the different frequency is superimposed on the original current of the relevant frequency. Therefore, when a ground fault occurs in the power transmission line of the frequency under the condition that the different frequency and the parallel line of the frequency exist, the induced circulating current of the different frequency may be superimposed on the ground fault current of the frequency. Conceivable.

  When the induction circulating current of different frequency is superimposed on the ground current of that frequency, the zero phase current becomes a vector sum of different mutual components of the angular velocity of the frequency and the different frequency, with a period according to the frequency difference between them Expanding and contracting, the phase with the zero phase voltage rotates. Thereby, when the protection device installed in the power transmission line of the frequency performs failure detection and fault point determination, a problem occurs in which the protection device periodically repeats operation and non-operation or performs unnecessary operation. Such a defect may occur not only in the fault line but also in the sound line without fault. The above events will be described using the equivalent circuit of FIG. 5 and the waveform diagram of FIG. Fig. 5 is an equivalent circuit showing the superposition of the induced circulating current, Fig. 6 (a) is a waveform diagram showing an example of superposition of the induced circulating current of different frequency, and Fig. 5 (b) is the position of zero phase current and zero phase voltage to be superposed. It is a wave form diagram showing a phase difference.

[Concept of superposition of different frequencies]
FIG. 5 shows that the induced circulating current kIom of different frequency fm is superimposed on the ground fault current Iob of the frequency fb flowing through the power transmission line l, n. The induced circulating current kIom of the different frequency fm is a value corresponding to the three-phase unbalanced permeability (in FIG. 5, the conductivity) of the induced magnetic field by the transmission current Iom flowing through the transmission line m of the different frequency fm. The power transmission line l and the power transmission line n circulate.

  The ground fault detection of the transmission line is to detect the fault current generated in the direction of the line from the zero phase current Io and the zero phase voltage Vo of the transmission line end, and the ground fault detection in FIG. The electric station Ass end of the transmission line 1 of the frequency fb is illustrated as a representative. The induced circulating current kIom of the different frequency fm superimposed on the ground fault current Iob of the frequency fb is superimposed in the reverse direction on the power transmission line 1 at the electric station Ass end, and is superimposed on the power transmission line n in the same direction.

  At this time, the superimposing direction of the induced circulating current kIom of the different frequency fm is indeterminate because it is controlled by the different frequency fm and the phase of the transmission current Iom of the transmission line m. Further, the phases of the zero-phase current Io and the zero-phase voltage Vo rotate while oscillating with a frequency difference cycle of the frequency fb and the different frequency fm.

  The waveform example shown in FIG. 6 schematically shows the relationship between the phases of the zero phase current Io and the zero phase voltage Vo. Here, the frequency fb is 50 Hz, the zero-phase current Io and the zero-phase voltage Vo both are 1 PU in phase, and the different frequency fm is 60 Hz and the induced circulating current kIom of different frequency fm is 1 PU. Shows the waveform calculated in

で、回転する。その結果、当該周波ｆｂの地絡故障Ｉｏｂにおいて、故障検知及び故障点標定を行う保護装置が、周期的に動作と不動作を繰り返す、あるいは、不要動作を行う等の不具合が起きることになる。 As shown in FIG. 6A, the superimposed wave of the zero-phase current Io in which the induced circulating current kIom of the different frequency fm and the ground fault current Iob of the frequency fb are superimposed has a 10 Hz period, which is the frequency difference between them. It becomes a vibration wave. As shown in (b) of FIG. 6, the phase difference Δφ Vo ∠ Io between the zero phase current Io and the zero phase voltage Vo has a period t in which the angular velocity difference between the two is 2π, that is,

And rotate. As a result, in the ground fault Iob of the frequency fb, a protection device that performs failure detection and fault location periodically repeats operations and non-operations, or performs problems such as performing unnecessary operations.

  As described above, in the situation where the different frequency fm and the parallel line of the relevant frequency fb exist close to each other, the induced circulating current kIom of the different frequency fm is superimposed on the ground current Iob of the relevant frequency fb. There was a possibility that a fault might occur in the fault detection. Therefore, in order to eliminate such a fault, a technique has been proposed in the past to remove the induced circulating current kIom of the superimposed different frequency fm, that is, the different frequency component, from the ground current Iob of the frequency fb.

JP 2012-39700 A

  In general, in order to stabilize the system, it is important to enhance high speed and reliability in failure detection and fault location. Therefore, the different frequency removal technology is required to further reduce the response characteristic time of the different frequency removal and to improve the removal performance. For example, with regard to the improvement of removal performance, in the conventional different frequency removal technology, when the different frequency fm itself changes greatly at intervals of the response characteristic time, the removal of the different frequency fm becomes difficult due to the influence. Therefore, it has been conventionally desired to reliably remove the different frequency even if the different frequency itself to be removed changes.

  The embodiment of the present invention is proposed to solve the problems as described above, and the response characteristic time can be speeded up and the removal performance can be improved, and the different frequency component superimposed on the relevant frequency can be quickly and It is an object of the present invention to provide an apparatus and method for removing different frequency waves that can be accurately removed.

In order to achieve the above object, in the embodiment of the present invention, an arbitrary power supply frequency is used as the frequency, and when an input frequency of the frequency is superimposed with another frequency having a frequency different from the frequency, The different frequency removing device for removing different frequency components from an input wave comprises the following components (1) to (8).
(1) A time series data storage unit which stores sampling values obtained by sampling the input wave at a predetermined sampling interval as time series data of an arbitrary time width.
(2) The frequency of the frequency, the frequency of the different frequency, the period time of the sampling interval serving as a reference, and the sampling number corresponding to the number of past permutations of the time series data based on the sampled current value Constant setting part to set arbitrarily as a constant.
(3) A removal coefficient calculation unit that calculates a different frequency removal coefficient for canceling the sum of the orthogonal components of the different frequencies by a logical expression previously determined using the constant.
(4) A compensation coefficient calculation unit which calculates a compensation coefficient for compensating the frequency expanded and reduced according to the angular velocity phase difference with the different frequency by a logical expression previously determined using the constant.
(5) A constant storage unit for storing the constant.
(6) A coefficient storage unit that stores the different frequency removal coefficient and the compensation coefficient.
(7) The current value sampled and the past value for the number of times of sampling are decomposed into orthogonal components according to the angular velocity of the frequency and the different frequency, and the orthogonal component is multiplied by the different frequency removal coefficient A different frequency removal operation unit that performs an operation to cancel the sum of the orthogonal components of the different frequencies according to.
(8) The frequency compensation operation unit that performs the compensation operation of the frequency by multiplying the sum of orthogonal components of the frequency by the compensation coefficient.
Also, the different frequency removal method can be understood as an embodiment of the present invention.

FIG. 1 is a block diagram showing a configuration of a first embodiment. BRIEF DESCRIPTION OF THE DRAWINGS The conceptual diagram of 1st Embodiment. FIG. 5 is a waveform chart for showing the effect of the first embodiment. FIG. 5 is a waveform chart for showing the effect of the first embodiment. Equivalent circuit showing superposition of induction circulation current. (A) is a wave form diagram showing the example of superposition of induction circulation current of different frequency, (b) is a wave form diagram showing the phase difference of the zero phase current and zero phase voltage to superimpose.

First Embodiment
Hereinafter, a first embodiment according to the present invention will be described using FIGS. 1 to 4. The first embodiment is a different frequency removing apparatus and method used when an induced circulating current of different frequency is superimposed on a ground current of the relevant frequency.

[Constitution]
As shown in the block diagram of FIG. 1, in the different frequency removing device 1, a time series data storing and updating unit 2, a constant setting unit 3, a removal coefficient calculation unit 4, a compensation coefficient calculation unit 5 and a storage register 6, the different frequency removal operation unit 7, and the frequency compensation operation unit 8 are provided. The different frequency removing device 1 is an arithmetic device having a storage area, and removes the component of the different frequency fm from the input wave Z in which the different frequency fm of 50 Hz is superimposed on the corresponding frequency fb of 60 Hz, for example. , The waveform of the said frequency fb is produced | generated and extracted.

  The time-series data storage and update unit 2 stores sampling values obtained by sampling the input wave Z at a predetermined sampling interval tsp as time-series data of an arbitrary time width, and updates the time-series data each time sampling. The constant setting unit 3 is a part for setting an arbitrary constant k. The constant k includes the frequency kfb of the frequency fb to be extracted, the frequency kfm of the different frequency fm to be removed, the reference sampling period ktsp, the number of times of sampling n and the like. The number of times of sampling n is a numerical value corresponding to the number of past permutations of time series data based on the sampled current value, and is an integer.

  The removal coefficient calculation unit 4 calculates different frequency removal coefficients k sin and k cos for removing the different frequency fm from the input wave Z according to a logical expression previously determined using the constant k, and stores these coefficients Send to register 6. The different frequency removal coefficients k sin and k cos are coefficients for canceling the sum of orthogonal components of the decomposed different frequency fm. The logical expression in the removal coefficient calculation unit 4 will be described later in the section of [logical expression].

  The compensation coefficient calculation unit 5 calculates a compensation coefficient kb for compensating the frequency fb according to a predetermined logical equation using the constant k, and sends this to the storage register 6. Since the frequency fb is scaled according to the angular velocity phase difference with the different frequency fm, the cancellation coefficient for returning this to the original value is the compensation coefficient kb. The logical expression in the compensation coefficient calculation unit 5 will also be described in the later section [logical expression].

  The storage register 6 is a storage unit which receives and stores the constant k, the different frequency removal coefficient ksin, kcos and the compensation coefficient kb from the constant setting unit 3, the removal coefficient calculation unit 4 and the compensation coefficient calculation unit 5, respectively. The constant k and the coefficients k sin, k cos and kb are arbitrary, and the constant setting unit 3 changes the setting of the constant k, and the removal coefficient calculation unit 4 and the compensation coefficient calculation unit 5 remove different frequency removal coefficients k sin, k cos and the compensation coefficient It is possible to recalculate kb. When the storage register 6 receives a new constant k or coefficient k sin, k cos, kb from the constant setting unit 3, the removal coefficient calculation unit 4 and the compensation coefficient calculation unit 5, the data is updated.

  The different frequency removal operation unit 7 performs the following operation. The different frequency removal operation unit 7 uses n past values Z (-1),..., N sampling times at discrete sampling intervals based on the current sampling value Z (0) and this value Z (0). For Z (−n), the input electrical quantities of the past n input waves Z are decomposed into orthogonal components by the rotation vector phase of each frequency. The orthogonal component has a value corresponding to the angular velocity of the frequency and the different frequency.

  Further, the different frequency removal operation unit 7 sets the different frequency removal coefficients k sin and k cos to the decomposed orthogonal components of the present sampling value Z (0) and the past values Z (−1),. The multiplication is performed to cancel the sum sinsin Zm of the vertical components of the different frequency fm. Further, the different frequency removal operation unit 7 performs an operation such as canceling out the sum cos cos Zm of the horizontal components of the different frequency fm to zero. The different frequency removal operation unit 7 removes the component of the different frequency fm from the input wave Z by performing these calculation processes. The above is the principle of the different frequency removal in the present embodiment.

  The frequency compensation calculation unit 8 multiplies the sum of orthogonal components of the frequency fb by the compensation coefficient kb. Thus, the frequency compensation calculation unit 8 performs a compensation calculation to restore the frequency fb scaled according to the angular velocity phase difference with the different frequency fm to the original value.

[Method of eliminating different frequencies]
As a specific example, the method of eliminating different frequencies by the current sampling value (0) and the past two points (-1) and (-2) will be concretely described with reference to the conceptual diagram of FIG. Describe. FIG. 2 shows the frequency to be extracted and the sampling vector phase of the different frequency to be removed, and three sampling values are taken. As shown in FIG. 2, the frequency fb to be extracted and the input electrical quantities Zb and Zm of different frequencies fm to be removed are rotations of the respective frequencies fb and fm at three points 0, -1, -2 of the sampling value. It is decomposed into orthogonal components by vector phases ωtb-0, ωtb-1, ωtb-2, ωtm-0, ωtm-1, ωtm-0. ωt is a sampling angular velocity of | Zb |, | Zm |, which is the RMS of each frequency fb, fm.

  The sampling interval tsp is constant, and | Zb |, | Zm | of the frequency fb and the different frequency fm are respectively set to 1 PU based on the current sampling value (0). The angular velocities of | Zb | and | Zm | of the respective frequencies fb and fm at the current sampling value (0) are both ωtb0 = 0 and ωtm0 = 0. That is, ωtb0 and ωtm0 are used as angular velocity reference points.

Table 1 below shows sampling angular velocities ωt of the frequencies fb and fm when the sampling frequency is 0, -1 and -2, respectively.
(Table 1)

[Formula]
In Table 1 and FIG. 2, the sum ΣZ of the orthogonal components for canceling out the different frequency fm to be removed and compensating the relevant frequency fb to be extracted is derived from the following (Equation 1).
(Formula 1)

In the removal coefficient calculation unit 4, different frequency removal coefficients ksin and kcos are determined using the frequency fb, the different frequency fm, and the sampling interval tsp as the known constant k. These coefficients are determined as a function of the above equation (1). Among these, the coefficient k sin is a coefficient for removing the vertical component of the different frequency fm, and the following (Expression 2) is satisfied.
(Formula 2)

When Z0 is a current sampling value, Zm is a sampling value of m times before, and Zn is a sampling value of n times before, the vertical component of the different frequency fm can be expressed as the following (Equation 3). kf is different frequency / corresponding frequency, and in this case, 50 Hz / 60 Hz = 0.833.
(Equation 3)

Since Z0 is 0 degrees and sin = 0, the above (formula 2) can be rewritten as the following (formula 4).
(Equation 4)

For example, if m = −4 and n = −8, k sin is − (0.3420201 / −0.984808) = 0.34729. However, as long as it is a value from the reference point 0, it may be anywhere and can be expressed as the following (Equation 5).
(Equation 5)

On the other hand, the coefficient k cos is a coefficient for removing the horizontal component of the different frequency fm, and satisfies the following (Expression 6).
(Equation 6)

Assuming that Z0 is a current sampling value, Zm is a sampling value of m times earlier, and Zn is a sampling value of n times before, the horizontal component of the different frequency fm can be expressed as the following (Equation 7).
(Equation 7)

すなわち、
（式９）

となる。 Since Z0 is cos = 1, the above (formula 6) can be rewritten as the following (formula 8).
(Equation 8)

That is,
(Equation 9)

It becomes.

  By multiplying the input electrical quantities Zb and Zm of the frequency fb and the different frequency fm by the different frequency removal coefficients ksin and kcos, the gain for the frequency changes. Therefore, in order to extract the accurate frequency fb, it is necessary to return the amplitude width before changing. Therefore, in the compensation coefficient calculation unit 5, the frequency fb, the different frequency fm, and the sampling interval tsp are known to be a constant k, and the compensation coefficient kb is obtained by the following (Equation 10). The compensation coefficient kb is also determined as a function of (Equation 1) above.

上記の（式１０）の直交成分総和で通過する抽出周波つまり当該周波の位相は変位する。このとき、当該周波の変位角は、（式１０）において、正弦率（右辺の分母の左側）と余弦率（右辺の分母の右側）との傾斜角となるが、電気量演算に関係する全ての入力波について、（式１）の処理を行うことで、変位角を相対的に一致させることができる。 (Equation 10)

The extraction frequency passing through the sum of the quadrature components of the above (Equation 10), that is, the phase of the frequency is displaced. At this time, the displacement angle of the corresponding frequency is the inclination angle between the sine rate (left side of the denominator on the right side) and the cosine rate (right side of the denominator on the right side) in (Equation 10). The displacement angle can be relatively matched by performing the processing of (Expression 1) for the input wave of

In this embodiment, the principle equation for decomposing the different frequency fm to be eliminated into orthogonal components and canceling out the sum ΣZm is the following (Equation 11), and the above (Equation 1) is an example thereof . The values of the coefficients k sin, k cos, kb, and which sampling number n the sampling value is multiplied by each coefficient are arbitrary. For example, the different frequency removal coefficients k sin and k cos are calculated and determined in advance as cancellation coefficients of orthogonal components (vertical axis k sin, horizontal axis k cos) according to arbitrary numbers of times 0, -1 and -2 by which sampling values are multiplied. Good.
(Equation 11)

[Action and effect]
In this embodiment, the different frequency removing device 1 includes the time series data storage / update unit 2, the constant setting unit 3, the removal coefficient calculation unit 4, the compensation coefficient calculation unit 5, the storage register 6, and the different frequency A removal operation unit 7 and the frequency compensation operation unit 8 are provided. In the different frequency removal operation unit 7, regarding the sampled current value Z (0) and the past value Z (-1),... Z (-n) for the number of sampling times n, each of the frequency fb and the different frequency fm It separates into orthogonal components according to the angular velocity, multiplies these orthogonal components by the different frequency removal coefficient k sin and k cos calculated by the removal coefficient calculation unit 4, and cancels the sum Σ sin Zm of the vertical components of different frequency fm The sum cos cos Z m of the horizontal components of the frequency fm is made zero.

  Thus, the component of the different frequency fm can be removed from the input wave Z on which the different frequency fm is superimposed. Further, the frequency compensation operation unit 8 multiplies the sum of orthogonal components of the frequency fb by the compensation coefficient kb obtained by the compensation coefficient calculation unit 5 to expand or reduce the frequency fb according to the angular velocity phase difference with the different frequency fm. To its original value. In this manner, only the accurate frequency fb can be extracted from the input wave Z of the frequency fb on which the different frequency fm is superimposed.

According to the present embodiment as described above, the following effects can be obtained.
(1) Improvement of removal performance due to change compression of different frequency itself In the present embodiment, when removing the different frequency fm, the variation of the transmission current Iom itself of the different frequency fm, which is the induction source of the relevant frequency fb, is not extracted. Therefore, in the present embodiment, even if the different frequency fm itself changes at intervals of the removal response characteristic time of the different frequency fm, there is no concern that the different frequency removal performance decreases due to this change. That is, according to the present embodiment, even if the magnitude of the different frequency fm to be removed changes, it is possible to reliably remove the component of the different frequency fm superimposed on the input wave Z, and the different frequency itself Changes can be compressed to improve removal performance.

[Removal method according to comparative example]
Hereinafter, when different frequency removal is performed by a method different from the present embodiment, that is, when different frequency removal is performed according to a comparative example to the present embodiment, a variation of the transmission current Iom itself of the different frequency fm is extracted Explain the problems and the problems caused by it. In the removal method according to the comparative example, for example, each time sampling, time-series data of a predetermined sampling interval cycle is updated and stored as Z0, Z-1, Z-2. Then, for the stored time-series data, it is assumed that the subtraction value ΣIo is calculated using the current sampling value Z0 and the past sampling value Zn (predetermined number n) according to the logical expression of the following equation (12).

In Equation (12), ωθb and ωθm are angular velocities of respective frequencies of past sampled values, Iob is a ground fault current of the corresponding frequency shown in FIG. 5, and Iom is the different frequency shown in FIG. It is a transmission line current.
(Expression 12)

A subtraction interval period n · tsp obtained by multiplying the predetermined sampling interval tsp by the past sampling number n is a time during which the angular velocity displacement difference between the frequency fb and the different frequency fm is π. These relations become following (Formula 13) and n is an integer.
(Equation 13)

Assuming that the sampling interval tsp = 0.001 sec is constant, the different frequency fm is 50 Hz, and the frequency fb is 60 Hz, these numerical values are applied, and the above (Equation 13) is the subtraction interval period n · tsp = 0 .05 sec, the number of samplings in the past = 50 times. Therefore, if the subtraction interval period n · tsp = 0.05 sec is substituted into the above (formula 12), the subtraction value ΣIo can be obtained from the following (formula 14).
(Equation 14)

となる。 At this time, assuming that both the frequency fb and the different frequency fm are past sampling angular velocity .omega..pi.
(Equation 15)

It becomes.

となり、異周波成分を相殺することが可能である。 In the above-mentioned (Formula 14), the transmission / reception current Iom of different frequency fm is included in the cancellation removal part of the different frequency component. Therefore, if it is assumed that the current value of the transmission current Iom is Iom ′ ′ and the past value is Iom, then Iom = Iom ′ ′
(Equation 16)

It is possible to cancel out different frequency components.

となり、送電電流Ｉｏｍの今回値Ｉｏｍ”と過去値Ｉｏｍとの差、すなわち異周波ｆｍの送電電流Ｉｏｍ自身の変化分が抽出されることになる。 However, if the current value Iom of the transmission current Iom and the past value Iom are not equal,
(Equation 17)

Thus, the difference between the current value Iom of the transmission current Iom and the past value Iom, that is, the variation of the transmission current Iom of the different frequency fm is extracted.

  As described above, in the comparative example, since the variation of the transmission current Iom itself of the different frequency fm is extracted, if the different frequency fm itself changes at an interval of the removal response characteristic time of the different frequency fm, it is affected. It becomes difficult to cancel out the different frequency components. On the other hand, in the embodiment, the variation of the transmission current Iom itself of the different frequency fm is not extracted in the logical expression for canceling the different frequency fm to be removed.

  Therefore, even if the different frequency fm itself changes at an interval of the elimination response characteristic time of the different frequency fm, it is not affected. Further, even if the different frequency fm largely changes at intervals of the response characteristic time, the component of the different frequency fm superimposed on the input wave Z can be reliably removed. Thereby, it is possible to improve the elimination performance of the different frequency fm.

(2) Shortening response characteristic time of different frequency removal In the removal method according to the comparative example described above, the subtraction interval period n · tsp shown in the above (Equation 13) is the angular velocity displacement between the relevant frequency fb and the different frequency fm It is the time when the difference is π. This means that, at the time of removing the different frequency fm, the sampling frequency n of the integral common multiple in which the angular velocity displacement difference between the relevant frequency fb and the different frequency fm is π is used. That is, the subtraction interval period n · tsp is restricted by the frequency fb and the different frequency fm. Under such restrictions, the response characteristic time changes or extends depending on the frequency range, and the response characteristic time I can not deny the delay of

  On the other hand, in the present embodiment, the subtraction interval period n · tsp, which is restricted by the frequency fb and the different frequency fm, is not used. Therefore, according to this embodiment, it is possible to shorten the response characteristic time without changing or extending the response characteristic time depending on the frequency range.

  Further, in the present embodiment, the removal coefficient calculation unit 4 calculates the different frequency removal coefficients ksin and kcos in advance, and the different frequency removal operation unit 7 orthogonalizes the different frequency fm using the different frequency removal coefficients ksin and kcos. The sum of the components can be offset. In addition, the compensation coefficient calculation unit 5 calculates the compensation coefficient kb in advance, and the frequency compensation operation unit 8 compensates for the frequency expanded or reduced in a cycle according to the frequency difference with the different frequency using this compensation coefficient kb. can do.

  As described above, both operation units 7 and 8 do not need to calculate the different frequency removal coefficient k sin, k cos or the compensation coefficient kb, the calculation processing time becomes short, and the response characteristic time of the different frequency fm removal is further accelerated. be able to. That is, according to the present embodiment in which the response characteristic time is accelerated, it is possible to contribute to speeding up and increase the reliability of failure detection and fault point determination, and to contribute to the stabilization of the system.

  The shortening of the response characteristic time described above will be specifically described with reference to the waveform chart of FIG. In FIG. 3, the frequency fb to be extracted is 50 Hz, the different frequency fm to be removed is 60 Hz, and both are set to RMS = 1 PU. In the waveform of FIG. 3, when different frequency removal is performed by the removal method (referred to as a conventional method for convenience, the waveform of the middle stage is different from the present embodiment), different frequency removal is performed according to the present embodiment. It is the case. As shown in FIG. 3, the response characteristic time of the different frequency fm removal according to the present embodiment is about a half cycle. On the other hand, it takes about 3 cycles in the conventional method.

  In addition, the removal method called for convenience as the conventional method is the said comparative example for demonstrating the effect of this embodiment. In the comparative example, different frequency removal is performed on the statically calculated different frequency current superimposed wave Io basically according to the above-mentioned [differential frequency superposition concept]. In this method, as shown in FIG. 4, the response characteristic time of the different frequency removal of the addition operation wave IIo plotted on the relevant frequency Iob axis is the subtraction interval period n · tsp = 0.05 sec, and about three cycles of the relevant frequency It can be understood from the comparison with the different frequency current superimposed wave Io that the degree becomes.

(3) Degree of freedom of frequency to be removed and extracted In this embodiment, the frequency components fb and different frequencies fm are decomposed into orthogonal components according to the angular velocity, and these orthogonal components are canceled out. Therefore, when removing the different frequency fm superimposed on the frequency fb, there is no influence of the angular velocity difference between the frequency fb and the different frequency fm. In addition to this, in the present embodiment, the frequency fb and the different frequency fm alternate cycle, the sampling interval, the least common multiple, that is, the restriction of the time interval at which the angular velocity difference between the frequency fb and the different frequency fm is π, release It is done. That is, according to the present embodiment, any different frequency can be removed or extracted regardless of the frequency range of the frequency fb and the different frequency fm. As a result, the degree of freedom of the frequency to be removed and extracted is expanded, and the removal performance of different frequencies is further improved.

(4) Removal of different frequency phase difference alternation cycle error In this embodiment, the input wave Z is mutually operated on impedance, phase, etc. of the voltage and current in the input wave Z, and the same applies to the input wave Z of voltage and current. The component of the different frequency fm can be removed to eliminate the relative phase difference. That is, if different frequency removal is carried out, the phase will be shifted, but if different frequency removal is carried out for all the input electric quantities, the phase is totally shifted as a whole, so the phase difference due to the different frequency removal does not occur relatively . Therefore, the influence of the reactance change due to the different frequency phase to be superimposed can be suppressed.

  When a reactance change occurs due to the phase difference between the frequency fb and the different frequency fm, this change amount becomes an error of the measurement distance and is repeated in an alternating cycle of the frequency difference. This is called an alternating cycle error of the different frequency phase difference, and this error is a factor that reduces the accuracy of fault detection and fault location. In the present embodiment, it is possible to eliminate the alternating cycle error of the different frequency phase difference, and it is possible to further enhance the performance of the different frequency removal and contribute to the accuracy improvement of the failure detection and the fault location.

(Other embodiments)
The above embodiments are presented as an example herein and are not intended to limit the scope of the invention. That is, the present invention can be carried out in other various forms, and various omissions, replacements and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the invention described in the claims and the equivalents thereof as well as included in the scope and the gist of the invention.

  For example, the frequency detection unit detects the frequency by performing the removal operation of the different frequency with the frequency as the reference harmonic, and detects the different frequency by performing the removal operation of the frequency with the different frequency as the reference harmonic. The different frequency detection unit and a monitoring unit that monitors the induced circulation current to be superimposed on the current of the frequency may be provided. More specifically, when different frequency 50 Hz is superimposed on the frequency 60 Hz, the frequency detection unit performs an operation to remove 50 Hz with 60 Hz as a reference harmonic, and the different frequency detection unit performs 50 Hz as a reference harmonic And perform an operation to remove 60 Hz. At this time, since the current taken into the frequency detection unit and the different frequency detection unit is the same, two types of frequency detection can be performed by one different frequency removal apparatus.

  In addition, an induction circulating current includes one set of different frequency removing devices, one of which extracts the corresponding frequency serving as a reference harmonic and the other one extracts a different frequency serving as an induction harmonic of the corresponding frequency and superimposing it on the current of the corresponding frequency. You may make it provide the monitoring part which monitors. According to such a different frequency removing device, it is not necessary to mount two types of operation units in one device, so that the configuration of each device can be simplified.

  In addition, it is applied to an operation mode in which the power system is switched to any one of frequency power sources, and a power source discrimination unit is provided which includes a different frequency removing device and mutually extracts reverse harmonics to discriminate power sources to be operated. It may be provided.

  Furthermore, a power supply mix detection unit for the power supply and the different power supply may be provided, and the safety is further improved by efficiently detecting the interaction between the power supply for the frequency and the different power supply for the different frequency. It can be done.

1 ... different frequency removing device 2 ... time series data storage and updating unit 3 ... constant setting unit 4 ... removal coefficient calculation unit 5 ... compensation coefficient calculation unit 6 ... storage register 7 ... different frequency removal operation unit 8 ... concerned frequency compensation operation unit

Claims (6)

In a different frequency removing device for removing a different frequency component from the input wave, wherein an arbitrary power supply frequency is the frequency, and a different frequency having a frequency different from the frequency is superimposed on the input wave of the frequency,
A time-series data storage unit that stores sampling values obtained by sampling the input wave at predetermined sampling intervals as time-series data of an arbitrary time width;
The frequency of the frequency, the frequency of the different frequency, the period time of the sampling interval serving as a reference, and the number of times of sampling corresponding to the number of past permutations of the time series data based on the sampled current value Constant setting unit to be set to
A removal coefficient calculation unit that calculates a different frequency removal coefficient for canceling the sum of the orthogonal components of the different frequencies by a logical expression that is predetermined using the constant;
A compensation coefficient calculation unit that calculates a compensation coefficient for compensating the frequency that has been scaled according to the angular velocity phase difference with the different frequency by a logical expression that is predetermined using the constant;
A constant storage unit for storing the constant;
A coefficient storage unit that stores the different frequency removal coefficient and the compensation coefficient;
The current value sampled and the past value for the number of sampling times are decomposed into orthogonal components according to the angular velocity of the frequency and the different frequency, and the orthogonal component is multiplied by the different frequency removal coefficient A different frequency removal operation unit that performs an operation to cancel the sum of orthogonal components of the frequency;
A frequency compensation operation unit for multiplying the sum of orthogonal components of the frequency by the compensation coefficient to perform a compensation operation of the frequency. The frequency detection unit that detects the frequency by performing the removal operation of the different frequency using the frequency as a reference harmonic;
A different frequency detection unit that detects the different frequency by performing the removal operation on the different frequency using the different frequency as a reference harmonic;
The inter-frequency rejection device according to claim 1, further comprising: a monitoring unit that monitors an induced circulating current superimposed on the current of the frequency. A set of the different frequency removing device according to claim 1, one of which extracts the corresponding frequency serving as a reference harmonic, and the other which extracts a different frequency serving as an induction harmonic of the corresponding frequency, different frequency removing device you comprising the monitoring unit for monitoring the induced circulating current to be superimposed. 4. The different frequency removing device according to any one of claims 1 to 3 , further comprising: a power supply cross talk detecting unit which detects a collision between the power supply of the frequency and the different power supply of the different frequency. The inter-frequency removal apparatus according to any one of claims 1 to 4 , further comprising a time-series data update unit that updates the time-series data each time sampling is performed. In the different frequency removal method for removing different frequency components from the input wave, where an arbitrary power supply frequency is the frequency, and a different frequency having a frequency different from the frequency is superimposed on the input wave of the frequency,
A time-series data storage step of storing sampling values obtained by sampling the input wave at predetermined sampling intervals as time-series data of an arbitrary time width;
The frequency of the frequency, the frequency of the different frequency, the period time of the sampling interval serving as a reference, and the number of times of sampling corresponding to the number of past permutations of the time series data based on the sampled current value The constant setting process to be set to
A removal coefficient calculation step of calculating a different frequency removal coefficient for offsetting the sum of the orthogonal components of the different frequencies by a logical expression previously determined using the constant;
A compensation coefficient calculation step of calculating a compensation coefficient for compensating the frequency expanded or reduced according to the angular velocity phase difference with the different frequency by a logical expression previously determined using the constant;
A constant storing step of storing the constant;
A coefficient storing step of storing the different frequency removal coefficient and the compensation coefficient;
The current value sampled and the past value for the number of sampling times are decomposed into orthogonal components according to the angular velocity of the frequency and the different frequency, and the orthogonal component is multiplied by the different frequency removal coefficient A different frequency removing operation step of performing an operation to cancel the sum of orthogonal components of the frequency;
A frequency compensation operation step of multiplying the sum of orthogonal components of the frequency by the compensation coefficient to perform a compensation operation of the frequency.

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