JP5492495B2 - Ground fault distance protection relay device - Google Patents

Description

  The present invention relates to a ground fault distance protection relay device for detecting a ground fault in a parallel two-line power transmission system with a neutral point grounded at a high resistance. The present invention relates to a ground fault distance protection relay device using a feather amount.

  Conventionally, as a protective relay device for detecting a ground fault in a parallel two-line power transmission system with a neutral point grounded with high resistance, a ground fault direction protective relay device has been variously used.

  The ground fault detection by this direction determination operates even in the case of a ground fault in an adjacent section, so the selection of the accident section is performed by timed cooperation. In this case, it is necessary to set a longer time limit at the power supply end in order to cut off the ground fault direction protective relay device in order from the load end. There was a problem that time was slow.

  In power systems that are difficult to coordinate in a timed manner as described above, by applying a distance protection relay device with excellent section discrimination, it is possible to quickly remove accident sections and facilitate cooperation with adjacent sections. .

  However, when the ground fault distance protection relay device is applied to the high resistance grounded power transmission system, it is necessary to solve some problems. Because the neutral point is grounded with high resistance, the fault current at the time of ground fault is limited, and it may be smaller than normal load flow, or the voltage and current of the protective relay installation terminal Since distance calculation is performed, there is a problem that the residual voltage due to the fault point resistance becomes an error factor.

  Japanese Patent Laid-Open No. 2008-295144, “Ground Fault Distance Relay” is known as a technique for ground fault distance protection relay device that solves these problems. This proposes that the amount of polarity is obtained from the difference current between the lines of the parallel two-line transmission line and that the amount of feather is used for the distance measurement calculation.

JP2008-295144

  In the publicly known example, it is proposed to use a feather amount for distance measurement calculation. Here, in the known example, the proposed formula only expressed the distance calculation formula in terms of the amount of feather, and how to actually use the amount of feather when actually configuring a ground fault distance protection relay device Detailed methods are not disclosed.

  As mentioned earlier, when applying a ground fault distance relay to a high-resistance grounded power transmission system, there are some contrivances even if the amount of feather is used because the ground fault current is small. Need.

  An object of the present invention is to obtain a polarity amount from the difference current between lines of a parallel two-line transmission line, and to use a feather amount for distance calculation, a ground fault distance protection relay of a specific device configuration that can be put to practical use. To provide an apparatus.

In the present invention, when realizing a ground fault distance protection relay device that protects the transmission line by calculating the distance to the accident point when a ground fault occurs in the parallel two-line transmission line of the high resistance grounding system,
Means for detecting the current and voltage of the transmission line, means for analog-digital conversion of the output of the detection means, means for converting the output of the conversion means into a feather amount, current of the own line and the adjacent line converted into the feather amount Means for deriving the difference current by using the difference amount, polarity amount calculation means for outputting a signal obtained using the difference current of the means as a polarity amount, the output of the polarity amount calculation means and the feather amount of the own line voltage. It is comprised from the calculation means which calculates the distance to a fault fault point, and discriminate | determines a ground fault.

  According to the present invention, when the amount of polarity is obtained from the difference current between the lines of the parallel two-line transmission line, and the amount of feather is used for the distance measurement calculation, a ground fault distance protection relay of a specific device configuration that can be put to practical use. An apparatus can be provided.

The block diagram of the ground fault distance protection relay device which is one Example of this invention Diagram explaining that the second circuit current in two-phase theory is in phase with the accident current Characteristics diagram of ground fault distance protection relay device Prior blocking judgment logic applied to the present invention

  Examples of the present invention will be described below.

  FIG. 1 is a block diagram showing an embodiment of the present invention, and particularly shows each function provided to a microprocessor or the like as a block.

  FIG. 1 shows the overall configuration of the ground fault distance protection relay device. Of these, the ground fault distance protection calculation means 14 executes the distance calculation formula up to the ground fault point. A plurality of inputs are taken into 14, and all the inputs are set to the feather amount by the feather amount conversion means 111, 112, 113 at the initial stage when they are input from the power system.

  As will be described in detail later, the feather amount derived by the feather amount conversion means is not a value that regularly fluctuates in time series like three-phase alternating current, but is a constant value in time series (affected by frequency fluctuations). It is characterized in that it is extracted as a value corresponding to the effective value of (No). In addition, in order to obtain processing information required by the ground fault distance protection calculation means 14 (for example, the amount of polarity calculated by the polar current calculation means 13), various phase shift operations or addition / subtraction operations are performed. The present invention is characterized in that the feathering amount obtained as a value corresponding to the value is used.

  Hereinafter, the present invention will be described in detail. First, the determination of the amount of polarity used in the ground fault distance protection calculation means 14 will be described.

Although not shown in FIG. 1, the detected value I of the three-phase alternating current of the digitally converted own line obtained via the own line current detector and the analog-digital converter of the parallel two-line transmission line system ₁ is added to the feather amount conversion means 111. Similarly, the detection value I ₂ of the three-phase alternating current of the digitally converted adjacent line obtained via the adjacent line current detector and the analog-digital converter of the parallel two-line transmission line system not shown is the amount of feather. Added to the conversion means 112.

  Note that, as the current input to the feather amount conversion means and converted, a zero-phase current is taken in addition to the three-phase currents.

The feather amount conversion means 111 and 112 are means for calculating the amount of feather decomposed into real part and imaginary part from each digitally converted instantaneous value input, and as a result, the real part feather amount Re ( I _1), the imaginary part feather weight Im (I ₁ of the own line current), the real part feather weight Re (I ₂ next line current), the imaginary part feather weight Im (I ₂ next line _current) is calculated.

この関数は、基本角速度をω_０、基本周波数をｆ_０とおくと(1)式が成立する。
但しω_０＝２πｆ_０＝2π/Tである。 In the present invention, the transmission line current is converted into a feather amount immediately after it is digitally input via a current detector and an analog-digital converter. Here, the concept of the feather amount will be described as follows.

In this function, when the basic angular velocity is ω ₀ and the basic frequency is f ₀ , the equation (1) is established.
However, ω ₀ = 2πf ₀ = 2π / T.

  Here, the individual harmonic components can be obtained by equations (2) and (3).

  This Fourier series is an expression for continuous data, and arithmetic methods such as DFT and FFT derived from discrete Fourier transform are known to handle sampled discrete data as in a digital protection relay device.

  However, the DFT requires a considerably large amount of calculation, and even in a high-speed FFT, there is a restriction that the data amount of one cycle must be a power of two. In the case of digital protective relays that must perform high-speed calculations, if the FFT method is used, special sampling such as electrical angle of 45 degrees (8 data) and 22.5 degrees (16 data) results, which is not practical, so it is further simplified A simplified approach is required.

  Considering data with an electrical angle of 30 degrees pitch (12 per cycle) and approximating (2) and (3) by simply replacing the integral with Σ, the approximate expression (4) and (5) is established.

  Further, since this equation is T = 12, in the case of 30 degree data, Equations (6) and (7) are obtained.

The meaning of this formula is, for example, when considering only the fundamental wave, a ₁ is a value obtained by multiplying a value g (t) obtained by sampling the AC waveform g at an arbitrary time t by a coefficient determined by the cos function, and sampling 30 degrees. It can be said that the calculation is performed each time, and this is calculated and added for one period of the AC waveform. b ₁ is different only in that the sin function is similarly applied. The size of a ₁ or b ₁ calculated in this way can be said to be a size corresponding to the effective value of the AC waveform.

A _n determined in this manner is the real part of the feather amount, b _n is the imaginary part of the feather amount. As is clear from this equation, there is no frequency-related term in equations (6) and (7), so it can be understood that the data is not affected by frequency fluctuations at the time of the accident.
In the present invention, since the sampling cycle is performed at a pitch of 30 degrees, it can be used as it is without changing the sampling cycle of an existing digital protection relay device. In addition, although it is used simply by setting the period to be 45 degrees originally to 30 degrees, in the case of a system with a small amount of data (required harmonic order is small), it shows almost the same performance as FFT. It has been confirmed. Sufficient accuracy is obtained at least in the range of the fundamental wave to the third harmonic, and sufficient performance can be exhibited as a characteristic of the protective relay device.

In this way, when the final output obtained from the feather amount conversion means is obtained, for example, only by the fundamental wave component, 2 consisting of a real part a ₁ and an imaginary part b ₁ with respect to one three-phase AC quantity (eg, a-phase current). It can be expressed by two numerical values, and can be expressed as a ₁ + jb ₁ when expressed as a complex number. Further, the size of each real part and imaginary part is not a time-series fluctuation numerical value, but is characterized in that it is extracted as a value corresponding to an effective value.

The current of each phase of each line obtained from the feather amount conversion means 111 and 112 in FIG. 1 is input to the difference current calculation means 12 in order to calculate the second circuit current in the two-phase circuit theory. Here, the difference between the input current of the own line and the adjacent line current of the feather amount is taken, and the feather amount (real part feather amount Re (I ₁ -I ₂ ), imaginary part feather amount Im (I ₁ -I ₂ ).

  Here, the physical meaning of taking the difference between the own line current and the adjacent line current in the difference current calculation means 12 will be described with reference to FIG.

  FIG. 2 is a diagram representing a parallel two-line transmission line to which the present invention is applied in two-phase circuit theory. This equivalent circuit is composed of six closed circuits, and sequentially from the top, the positive phase first circuit, the positive phase second circuit, the negative phase first circuit, the negative phase second circuit, the zero phase first circuit, and the zero phase second circuit. It is.

  Of these, the first circuit is an equivalent circuit for the circuit formed between the transmission line and the ground via the neutral point resistance, and the second circuit is the circuit formed between the parallel two-line transmission lines. Is an equivalent circuit. The calculation result of the difference current calculation means 12 in FIG. 1 is the current difference between the own line current and the adjacent line current (current flowing back between the two lines), and this is the current of the second circuit in FIG. means.

  The polarity current calculation means 13 calculates the polarity current using the positive phase current, the reverse phase current, and the zero phase current. Normally, the polarity amount calculation means performs any one of the positive phase current calculation, the reverse phase current calculation, and the zero phase current calculation, and the same effect can be obtained in any method.

  The effectiveness of the method of using the second circuit current as the polarity current can be explained by an equivalent circuit shown in FIG. The meaning of this circuit is as described above, and will be described in detail below.

  The main promise of the symbol notation used here is that the lowercase letters 1, 2, and 0 attached to the impedance Z represent the positive phase component, the negative phase component, and the zero phase component, respectively. The symbols BA, BB, and L attached to the impedance Z mean the rear impedance at the transmission line A end, the rear impedance at the B end, and the transmission line impedance. Of the numerical values of 11, 12, 21, 22, 01, 02 attached to the current I, the upper digits represent the positive phase, the negative phase, and the zero phase, and the lower digits 1, 2 represent the first circuit, It means the current of the second circuit.

In this figure, a method of obtaining a polarity current becomes a current I _F the same phase through the fault point resistance here placed with R _F of the own terminal current (detected in CT in Fig. 2) has a positive phase second circuit It can be implemented by using either the anti-phase second circuit or the zero-phase second circuit.

The reason why the first circuit cannot be used is that the back impedance ( _ZBA1 , _ZBB1 , _ZBA2 , _ZBB2,. By having Z _BA0 , Z _BB0 ). In other words, the A terminal side (left side of the figure) and the B terminal side (right side of the figure) of the first circuit have different values of impedance, resulting in different impedance angles. fault current I _F is the self-terminal circuit, will be diverted with a phase difference to the mating terminal circuit, the detection current I and fault current I _F of the own terminal is not in phase, it can not be applied as a polarity current.

On the other hand, the second circuit currents, such as behind the impedance _{(Z BA1, Z BB1, Z} BA2, Z BB2, Z BA0, Z BB0), no impedance different for each terminal, only some of the line impedance Z _L is there. In this case, in any accident point, since the impedance angle are the same, the own terminal circuit, fault current flowing through the mating terminal circuit although different size, it is the fault current I _F and phase error used as a polarity current The effect of minutes can be eliminated.

Here, the fact that the impedance angle is the same will be described by taking the zero-phase second circuit as an example. Between the impedance Z _L0 , the resistance R _L0 and the reactance L _L0 ,
Z _L0 = R _L0 + jωL _L0
∠Z _L0 = tan ^-1 (ωL _L0 / R _L0 )
The relationship is established.

At this time, kZ _L0 = k (R _L0 + jωL _L0 ) in the left circuit.
∠ (kZ _L0 ) = tan ⁻¹ ((k · ωL _L0 ) / (k · R _L0 )) = ∠Z _L0
Is established.

In the right circuit
(1-k) Z _L0 = (1-k) ・ (R _L0 + jωL _L0 )
∠ ((1-k) Z _L0 ) = tan ⁻¹ (((1-k) · ωK _L0 ) / ((1-k) · R _L0 ))
= ∠Z _L0
As a result,
∠ (kZ _L0 ) = ∠ ((1-k) Z _L0 )
It becomes. This equation means that the impedance angle is the same.

  As is clear from the above description, using the output of the difference current calculation means 12 for obtaining the second circuit current of the two-phase theoretical circuit, either the positive phase current, the negative phase current, or the zero phase current of the second circuit is used. Can be used as a polar current.

By the way, as described above, the output of the feather amount conversion means 111 and 112 is a value corresponding to the effective value. Accordingly, the processing in the difference current calculation means 12 may be performed by adjusting the numerical values of the real part and imaginary part, but in the polar current calculation means 13, the a-phase current Ia = a _1a + jb _1a as the feather amount It is necessary to perform a phase shift process using the b-phase current Ib = a _1b + jb _1b , the c-phase current Ic = a _1c + jb _1c, and the phase operator a. Here, it is assumed that the fundamental wave is handled, and the calculation of the antiphase amount I ₂ can be understood as follows. In various operations of the protective relay device, inner product calculation, phase shift processing, and final size may be obtained. However, in the calculation using the feather amount, it may be handled as a complex number. Good.

  As is clear from the above description, in the present invention, the electric quantity used in the distance measurement calculation is first converted to a feather quantity to obtain a value corresponding to the effective value, and then various addition / subtraction calculations, phase shifts are performed. Process. This is effective in improving the accuracy of the distance measurement calculation.

  In other words, since the accident current is small, this measurement itself is difficult, and in addition to the problem that a slight phase shift of the measured value greatly affects the calculation result, the former is solved as a problem of the current detector. Is possible. However, for the latter, the concept of simply introducing the feather amount is not sufficient, and it can only be achieved by following the procedure of “convert first, then perform various addition / subtraction and phase processing”. is there. Even if this value is converted into a feather amount after calculating the polarity amount, this feather amount already includes the effect of frequency fluctuation or phase fluctuation at the time of the accident, and the accuracy of distance measurement calculation cannot be improved. is there.

  The polar current Ipol calculated by the polar current calculation means 13 is input to the ground fault distance protection calculation means 14 and used for distance calculation. The ground fault distance protection calculation means 14 includes a feather amount of the own line current output from the feather amount conversion means 111, a self-terminal voltage detector (input converter) not shown in the figure, and analog-digital. The detected value “V” of the digitally converted three-phase AC voltage obtained through the converter is added to the feather amount conversion means 113, and the feather amount of the self-end voltage as a result is input.

  In the ground fault distance calculation means 14, ranging calculation can be executed by various calculation formulas. In the present invention, calculation using the amount of feather will be described by formula (14) described later as an example. .

First, the state of the electric power system before the occurrence of the accident is as follows: a phase voltage Va, a phase current Ia, impedance Z, zero phase current I0 and voltage V0, reverse phase current I2 and voltage V2, positive phase current I1 and voltage V1 When expressed using the impedance Z0, Z2, Z1 of the zero-phase, negative-phase, and positive-phase circuit,
Va = V1 + V2 + V0 + V0m
Ia = I1 + I2 + I0 + I0m
Z = Z1 + Z2 + Z0 + Z0m
Each holds.

  In this equation, “m” means zero-phase voltage, zero-phase current, and zero-phase impedance due to mutual induction of parallel two-line transmission lines.

This formula is established in the state before the accident. Similarly, if the line impedance up to the accident point at this time is expressed as Zf at the time of the accident,
Va = V1 + V2 + V0 + V0m
= Zf1, I1 + Zf2, I2 + Zf0, I0 + Zf0m, I0m

Holds. However, Zf1, Zf2, and Zf0 are the positive phase, negative phase, and zero phase components of the line impedance up to the accident point.

Also, when Z2 = Z1 at the time of the ground fault,
Va = Zf1, I1 + Zf1, I2 + Zf0, I0 + Zf0m, I0m
= Zf1, I1 + Zf1, I2 + Zf1, I0-Zf1, I0 + Zf0, I0 + Zf0m, I0m
= Zf1 (I1 + I2 + I0) + (Zf0-Zf1) + Zf0m ・ I0m
= Zf1 ・ Ia + (Zf0-Zf1) I0 + Zf0m ・ I0m
It becomes.

Furthermore, if this expression is expanded in a complex number expression with Z = R + jX,
Va
= Rf1 ・ Ia + (Rf0-Rf1) I0 + Rf0m ・ Im + jXf1 ・ Ia + (jXf0-jXf1) I0 + jXf0m ・ Im
= Rf1 ・ Ia + (Rf0-Rf1) I0 + Rf0m ・ Im + Xf1 ・ jIa + (Xf0-Xf1) jI0 + Xf0m ・ jIm
Can also be expressed.

  Next, calculate Equation (9) by dividing both sides by Xf1.

  Further deformation and Xf1 are summarized as (10).

Here, assuming that the ratio of the impedances in the system is uniform, the impedance can be replaced as follows using the impedance of the entire system length.
Rf1 / Xf1 = R1 / X1, (Rf0-Rf1) / Xf1 = (R0-R1) / X1, Rf0m ・ Xf1 = R0m / X1,

(Xf0-Xf1) / Xf1 = (Z0-Z1) / Z1, Xf0m / Xf1 = X0m / X1
Furthermore, R1s = R1 / X1, R0s = (R0-R1) / X1, R0ms = R0m / X1,
X0s = (X0-X1) / X1, X0ms = X0m / X1
If the is a set value, the positive-phase reactance up to the accident point can be obtained by equation (11).

  By the way, in the principle formula (11), it is assumed that the ratio of each impedance in the system is uniform. However, since there is actually an accident point resistance and load impedance (both are considered to be resistance components), it is uniform. That's not true. Therefore, calculation is performed with an ineffective component for the fault current so as not to be affected by the resistance component as much as possible.

  Now consider the accident current as the polar current Ipol. Since Ipol is dominated by neutral point resistance NGR and accident point resistance, it is almost the amount of resistance component. Therefore, the amount in the same phase direction as the ineffective portion Ipol * of Ipol is considered to be an amount controlled by the reactance X with little influence of resistance. Therefore, the influence of resistance can be minimized by taking the inner product of Ipol * for the numerator and denominator.

  Equation (12) is the basic equation thus obtained.

In the present invention, the expression (12) is executed.
RI (t0) = RIs · Ia (t0) + R0s · I0 (t0) + R0ms · I0m (t0)
XI (t0) = Ia (t0) + X0s ・ I0 (t0) + Xoms ・ I0m (t0)
If the amount to be calculated in advance

It becomes.

  If Re and Im of each analog quantity are calculated in advance by Fourier series, Expression (13) is expressed as Expression (14) by the definition of the inner product and the inner product for the ineffective part.

  In the ground fault distance protection calculation means 14 of FIG. 1 of the present invention, the operation determination is performed based on the distance measurement calculation value and the set input value along the equation (14). (Va) and Im (Va) are obtained as outputs of the feather amount conversion means 113 of the self-end voltage in FIG. Similarly, Re (Ipol) and Im (Ipol), which are distance measurement calculation values, are obtained from the polar current calculation means 13.

  In contrast, settling input values Re (RI) and Im (RI) and Re (XI) and Im (XI) for transmission line impedance are set as numerical values calculated in advance. In the illustrated example, the self-line a phase has been described, but it goes without saying that the same processing and determination are performed in the same way for other bc phases of the self-line and adjacent lines.

  By doing so, it is possible to perform distance measurement calculation that is not truly affected by the frequency or phase fluctuation at the time of the accident.

  This ground fault distance calculation method may also operate in the healthy phase (ranging impedance is below the set value), so this ground fault distance protection relay is used to prevent unnecessary relay operation. The characteristics of the apparatus were the back cut characteristics as shown in FIG. This can be achieved, for example, by adjusting the reference value for determining the operation only when the value of Xf1 calculated by equation (14) is greater than or equal to a specific value (or less).

  In addition, for the purpose of preventing unnecessary operation of the healthy phase, the fault phase is selected by the fault phase selection means shown in 18 of FIG. 1, and the fault phase is selected according to the result and the result of the ground fault distance protection calculation means 14. The selection circuit 19 selects the result of the accident phase and outputs an operation.

  In FIG. 1, the accident phase selection means 18 includes a ground fault direction determination means 16 and an accident phase selection means 17. Among these, the ground fault direction determination means 16 is a detection value of a digitally converted three-phase AC voltage obtained through a self-end voltage detector (input converter) (not shown) and an analog-digital converter. The result “Vo” obtained by adding “V” to the zero-phase voltage calculation means 15, the own line current detector (input converter) of the parallel two-line transmission line system (not shown), and the analog-digital converter The detection value “Io1” of the zero-phase current of the digitally converted own line obtained via the input is input, and the accident point is located in the forward direction of the protective device from the phase difference between “Vo” and “Io1” at the time of the accident. The operation output is performed. The accident phase selection means 17 measures the minimum voltage of each phase voltage from the aforementioned self-terminal voltage “V”, selects the phase having the lowest voltage among the three-phase inputs as the accident phase, and outputs it.

  When the preceding interruption determination circuit 45 shown in FIG. 4 is preceded interruption after the occurrence of the ground fault (the counterpart terminal outputs the breaker opening command first and the breaker is opened), the zero-phase circulating current disappears, A countermeasure is taken to prevent the second circuit from being unusable because it is not a two-phase parallel parallel line.

  In this circuit, the overcurrent relay 64V that detects the ground fault operates, measures a certain time with the timer T, and then the accident current change relay 67DLK that detects the change in the accident current operates, so that the other end is leading Since it is detected that the second circuit has been cut off, the operation output of the ground fault distance protection relay device 14 using the second circuit as a polarity amount is locked in the blocking circuit 46.

  After the accident phase selection circuit 19 and the like, the operation output of the ground fault distance protection device is finally performed.

111, 112, 113 ... feather amount conversion means, 12 ... difference current calculation means,
13 ... Polarity current calculation means, 14 ... Ground fault distance protection calculation means,
15 ... Zero phase voltage calculation means, 16 ... Ground fault direction determination means,
17 ... Accident phase selection means, 18 ... Accident phase selection means,
19 ・ ・ ・ Accident phase selection logic,

Claims (7)

In the ground fault distance protection relay device that protects the transmission line by calculating the distance to the accident point when a ground fault occurs in the parallel two-line transmission line of the high resistance grounding system,
Means for detecting the current and voltage of the transmission line; means for analog-to-digital conversion of the output of the detection means; means for converting the current and voltage output from the conversion means into a feather amount; Means for deriving the difference current using the current of the line and the adjacent line, polarity amount calculation means for outputting a signal using the difference current of the means as a polarity amount, and the own line obtained from the output of the polarity amount calculation means A ground fault distance protection relay device comprising a calculation means for calculating a distance from a voltage feather amount to a ground fault point and determining a ground fault. In the ground fault distance protection relay device according to paragraph 1,
The output of the feather amount conversion means is a ground fault characterized in that the information about the real part and the imaginary part of the converted fundamental component of the feather amount is calculated as a value corresponding to the effective value. Distance protection relay device. In the ground fault distance protection relay device according to paragraph 1,
The analog-digital conversion means performs sampling at intervals of 30 degrees of the frequency of the transmission line voltage and current, and the feather amount conversion means implements the actual value from the fundamental component of the feather amount converted using the sampling values at intervals of 30 degrees. A ground fault distance protection relay device characterized by deriving a part amount and an imaginary part amount. In the ground fault distance protection relay device that performs distance calculation using the feather amount of the current voltage when the ground fault occurs in the parallel two-line transmission line of the high resistance grounding system,
Means for detecting the current and voltage of the transmission line; means for analog-to-digital conversion of the output of the detection means; means for converting the current and voltage output from the conversion means into a feather amount; Means for deriving the difference current using the current of the line and the adjacent line, polarity amount calculation means for outputting a signal using the difference current of the means as a polarity amount, and the own line obtained from the output of the polarity amount calculation means Reactance relay characteristics that include a back cut element to prevent unnecessary operation of the healthy phase in addition to the front element that operates at the calculated reactance X by calculating the distance from the voltage feather amount to the ground fault point A ground fault distance relay device characterized by having. In the ground fault distance protection relay device that performs distance calculation using the feather amount of the current voltage when the ground fault occurs in the parallel two-line transmission line of the high resistance grounding system,
Means for detecting the current and voltage of the transmission line; means for analog-to-digital conversion of the output of the detection means; means for converting the current and voltage output from the conversion means into a feather amount; Means for deriving the difference current using the current of the line and the adjacent line, polarity amount calculation means for outputting a signal using the difference current of the means as a polarity amount, and the own line obtained from the output of the polarity amount calculation means When calculating the distance from the voltage feather amount to the ground fault point,
By sampling detected at 30 ° period current and voltage in the transmission line analog - using a digital converted value, the real part a _n and the imaginary part b _n feather weight, instantaneous values g (t sampled the current-voltage ), Coefficient n and time t

A ground fault distance protection relay device characterized by being obtained as follows. When a ground fault occurs in a parallel two-line transmission line of a high resistance grounding system, the distance to the fault point is calculated, and the ground fault phase is cut off to protect the transmission line. In the electric device, means for detecting the current and voltage of the transmission line, means for analog-digital conversion of the output of the detection means, means for converting the current and voltage output from the conversion means into a feather amount, means for deriving the difference current by using the current of the transformed host circuit and the adjacent line, the polarity calculating means for outputting a signal with a differential current of the unit as a polar quantity, and an output of said polar amount calculating means Calculation means for calculating the distance to the ground fault point by calculating the distance from the obtained line voltage feather amount and ground fault accident phase selection for identifying the ground fault accident occurrence phase from the output of the analog-digital conversion means Means, the ground fault phase And an output of another device from an output of said calculating means and blocking means for performing a blocking of ground fault phase ground fault distance protective relay device. When a ground fault occurs in a parallel two-line transmission line of a high resistance grounding system, the distance to the fault point is calculated, and the ground fault phase is cut off to protect the transmission line. In the electric device, means for detecting the current and voltage of the transmission line, means for analog-digital conversion of the output of the detection means, means for converting the current and voltage output from the conversion means into a feather amount, means for deriving the difference current by using the current of the transformed host circuit and the adjacent line, the polarity calculating means for outputting a signal with a differential current of the unit as a polar quantity, and an output of said polar amount calculating means It is composed of calculation means for calculating the distance from the obtained line voltage feather amount to the point of the ground fault and determining the ground fault, and blocking means for detecting the preceding interruption of the mating terminal and blocking the output of the calculation means. Ground fault distance protection relay device.

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