JPH09304468A - Method for locating fault-point of parallel two line system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To locate a fault point of a ground fault of one line at one point of a power feed line consisting of high resistance parallel two lines with the use of current, voltage data of a zero-phase terminal not on the side of a power source. SOLUTION: Based on a zero-phase current of each line at a zero-phase terminal T2 not on the side of a power spruce, a differential current ΔI02 of lines is calculated, a zero-phase voltage V0 is the terminal T2 is calculated, a coefficient ρ is obtained from an equation ρ=Von .|ΔI02 |/Ion .|Vo | (Von is a rated zero-phase voltage and Ion is a ground fault current at the time of one line complete ground fault), and a distance (x) to a fault point from the terminal T2 is obtained according to (x)=d(1-ρ) ((d) is length of the line).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of locating a ground fault point of a high resistance two-terminal parallel two-line transmission line and a high resistance three-terminal parallel two-line transmission line.

[0002]

2. Description of the Related Art Power transmission between substations is generally performed by a parallel two-line system in order to improve reliability of power supply. Compared with the wiring managed in the building, the power transmission line has a failure caused by the outside (for example, dielectric breakdown due to lightning strike, contact of animals and trees). It involves point search work.

Therefore, various methods for locating a failure point have been proposed. For example, there is a method of obtaining the distance to the failure point by utilizing the fact that the zero-phase current shunt ratio of each line flowing into the failure point is proportional to the distance from the zero-phase power source end to the failure point (Japanese Patent Laid-Open Publication No. Sho. 63-200077). This is called the zero-phase current shunt ratio method. In this specification, symbols I, V, and Z represent vectors unless otherwise specified. Further, the "zero-phase non-power source end" refers to a terminal in the zero-phase circuit in which zero-phase current does not flow in or out.

FIG. 1 is a zero-phase equivalent circuit for explaining the zero-phase current shunt ratio method. It is shown that a zero-phase power source end T ₁ and a zero-phase non-power source end T ₂ of a two-terminal parallel two-line transmission line are connected. The space is composed of two lines 1L and 2L of length d. Zero-phase power supply terminal T ₁ of the line 1L, respectively zero-phase current I _011, I ₀₁₂ flows 2L, zero-phase non-power end T ₂ of the line 1L, zero-phase current respectively 2L I _021, I ₀₂₂ flows, zero It is _assumed that a ground fault has occurred in the line 1L at a distance x from the phase non-power source terminal T ₂ and the zero-phase fault current I _0f1 is flowing out.

In this case, using the zero-phase currents I ₀₁₁ and I ₀₁₂ , the distance dx from the zero-phase power source end T ₁ to the fault point can be calculated by the following equation. d−x = 2d | I ₀₁₂ | / (| I ₀₁₁ | + | I ₀₁₂ |) (1)

[0006]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
The formula is the influence of the load current component superimposed at the time of failure and the failure point.
Since it is not affected by resistance, it has high orientation accuracy.
However, terminal T, which is the zero-phase power source end₁Zero-phase current I₀₁₁,
I₀₁₂It is necessary to know that if the zero-phase power source end T₁
Zero-phase current I₀₁₁, I₀₁₂Not known, zero-phase non-power source terminal T
_TwoZero-phase current I at ₀₂₁, I₀₂₂Only when you know
Says that the distance x to the failure point cannot be calculated.
There was a problem.

Assuming that the zero-phase current I at the zero-phase non-power source terminal T _{2
Using 021} and I ₀₂₂ , an attempt is made to locate a failure point by assuming an equation x = 2d | I ₀₂₂ | / (| I ₀₂₁ | + | I ₀₂₂ |) similar to the above equation (1), At the zero-phase non-power source terminal T ₂ , the zero-phase currents I ₀₂₁ and I ₀₂₂ have opposite signs but the magnitudes are equal, so x is always d, and it can be seen that the failure point cannot be obtained.

Such a problem is that the zero-phase current measuring device at the zero-phase power source terminal T ₁ is abnormal and the zero-phase current cannot be measured, or the zero-phase current data at the zero-phase power source terminal T ₁ is stored in the center. When the communication line sent to the processor fails and the central processing unit cannot perform fault point location calculation based on the zero-phase current data, the zero-phase current at the zero-phase non-power source terminal T ₂ is used for orientation. It happens when you try.

Therefore, the present invention solves the above-mentioned technical problems, and determines a fault point of a one-point one-line ground fault of one line of a high resistance parallel two-line power transmission line as a current and a voltage at a zero-phase non-power source end. The purpose is to realize a fault location method that can be located using data.

[0010]

The method of the present invention will be described. (a) High-resistance 2-terminal parallel 2-line transmission line Fig. 2 shows an equivalent circuit based on the zero phase difference current of the high-resistance parallel 2-line transmission line. The length between the zero-phase power supply terminal T ₁ of the 2-circuit transmission line and the zero-phase non-power terminal T ₂ is d, zero-phase power supply terminal T ₁
The line-to-line differential current I ₀₁₁ -I ₀₁₂ is ΔI ₀₁ , and the line-to-line differential current I ₀₂₁ -I ₀₂₂ of the zero-phase non-power source terminal T ₂ is ΔI ₀₂ .

It is assumed that a ground fault has occurred in the line 1L at a distance x from the zero-phase non-power source terminal T ₂ , and the fault difference current is ΔI _0f . Since one line ground fault is assumed, Δ
Of course, I _0f = I _0f1 holds. After that,
ΔI _0f will be simply written as I _0f . According to the voltage drop law, (d−x) ΔI ₀₁ −xΔI ₀₂ = 0, (2) From the current conservation law, ΔI ₀₁ + ΔI ₀₂ = I _0f (3) holds.

Therefore, from equations (2) and (3), ΔI ₀₁ = xI _0f / d and (4) ΔI ₀₂ = (d−x) I _0f / d (5) are derived. Assuming that the zero-phase voltage at the zero-phase power source terminal T ₁ is V ₀₁ and the neutral point resistance is R _n , the fault current returns to the power source through the neutral point resistance R _n of the power source terminal, so | I _0f | = | V ₀₁ | / R _n (6) can be written. Here, when the magnitude of the zero-phase voltage at the time of complete one-line ground fault is V _0n , this is equal to the rated phase voltage E.

E = V _0n (7) When the equation (6) is used in the equation (7), | I _0f | = (| V ₀₁ | / R _n ) × (E / V _0n ) = (E / R _n ) × (| V ₀₁ | / V _0n ) (8) holds.

Here, it is utilized that the zero-phase voltage at the time of a one-line ground fault is almost unchanged at each terminal. Then, the zero-phase voltage V ₀₁ at the zero-phase power supply terminal T ₁ can be replaced with the zero-phase voltage V ₀₂ at the zero-phase non-power supply terminal T ₂ .
The formula (8) becomes | I _0f | = (E / R _n ) × | V ₀₂ | / V _0n (9) (E / R _n ) on the right side of the equation (9) is a zero-phase current at the time of a complete ground fault of the system, and is referred to as I _0n . Then, | I _0f | = I _0n · | V ₀₂ | / V _0n (10). That is, the fault current I _0f is the zero-phase non-power source terminal T ₂
Can be obtained from the zero-phase voltage V ₀₂ at 0, the zero-phase current I _0n at the time of a complete ground fault of the system, and the zero-phase voltage V _{0n at the time} of a complete ground fault of the system. Here, when ρ is defined by ρ = | ΔI ₀₂ | / | I _0f | (11), ρ is obtained by ρ = V _0n · | ΔI ₀₂ | / I _0n · | V ₀₂ |

The distance x from the zero-phase non-power source end T ₂ to the failure point x
Can be calculated by x = d (1-ρ) (13) by using the relation of this ρ and the equation (5). The distance d−x from the zero-phase power supply terminal T ₁ to the failure point is obtained by d−x = ρd by modifying the equation (13).

V _0n and I _0n in the equation (12) are constants unique to the system. Therefore, at the zero-phase non-power source terminal T ₂ ,
By measuring ΔI ₀₂ |, | V ₀₂ |, ρ can be obtained, and from this, the position x of the failure point can be obtained.
(b) High-resistance 3-terminal parallel 2-line transmission line Fig. 3 shows an equivalent circuit based on the zero phase difference current of the high-resistance 3-terminal parallel 2-line transmission line. The length between the zero-phase power source terminal T ₁ and the branch point S is d _1, and the length between the branch point S and the zero-phase non-power source terminals T ₂ and T ₃ is d ₂ and d ₃ , respectively. . Zero-phase power supply terminal T ₁
Line difference current I ₀₁₁ -I ₀₁₂ of ΔI ₀₁ , zero phase non-power source terminal T ₂ line difference current I ₀₂₁ -I ₀₂₂ of ΔI ₀₂ , zero phase non-power source terminal T ₃ line difference current I ₀₃₁ − _Let I ₀₃₂ be ΔI ₀₃ .

When a one-line / one-line ground fault occurs in the section ST ₂ , the equation corresponding to the above equations (4) and (5) is ΔI ₀₁ = (d ₃ x / D) I _0f (14) ΔI ₀₂ = [1- (d ₃ + d ₁ ) x / D] I _0f (15) ΔI ₀₃ = (d ₁ x / D) I _0f (16). Here, with _{D = d 2 d 3 + d} 3 d 1 + d 1 d 2, similarly to the case of (a), since the fault differential current [Delta] I _0f equals fault current I _0f, the [Delta] I _0f wrote I _0f .

As in the case of (a), the fact that the zero-phase voltage at the time of a one-line ground fault hardly changes at each terminal is used to approximate the zero-phase voltage at each end to the same value. it can. This written as V _0, considering that express a fault current using the V _0, the same formula as the formula (10), | I
_0f | = I _0n · | V ₀ | / V _0n (17) holds. That is, the fault current I _0f is the zero-phase voltage V ₀ at the time of the accident, the zero-phase current I _0n at the time of a complete ground fault of the system,
It can be obtained from the zero-phase voltage V _{0n at the time} of a complete ground fault of the system.

It will be considered to perform the orientation using the current-voltage data of the zero-phase non-power source terminal T ₂ . When ρ is defined by ρ = | ΔI ₀₂ | / | I _0f | (18), ρ is obtained by ρ = V _0n · | ΔI ₀₂ | / I _0n · | V ₀ | (19).

Distance x from the zero-phase non-power source terminal T _{2 of the} fault point
Is calculated from this ρ and the equation (15) by x = (1−ρ) D / (d ₁ + d ₃ ) (20). However, since the failure point is considered to be the section ST ₂ , it is necessary that x ≦ d _2, that is, ρ ≧ d ₁ d ₃ / D. From the above, based on the current-voltage data at the zero-phase non-power source terminal T ₂ , ρ is calculated from equation (19), and (20)
The distance x from the zero-phase non-power source terminal T ₂ to the failure point can be obtained by applying the equation.

If ρ <d ₁ d ₃ / D, the failure point exists in the section T ₁ S or the section ST ₃ outside the section ST ₂ . To identify whether it is the section T ₁ S or the section ST ₃ , the ρ ′ is ρ ′ = V _0n · | ΔI ₀₃ | / I using the current-voltage data of the zero-phase non-power source terminal T _{3. 0n} · | V ₀ | (21), and using this ρ ′, the distance from the zero-phase non-power source terminal T ₃ to the fault point y y = (1−ρ ′) D / (d ₁ + d ₂ ) ( 22) should be calculated (see Fig. 4).

If the obtained y is y ≦ d ₃ (that is, ρ ′ ≧ d ₁ d ₂ / D), the failure point is the section ST.
It can be seen that it exists in ₃ (see FIG. 4). ρ '<d ₁ d
_{If 2} / D, the failure point exists in the section T ₁ S (FIG. 5).
reference). When the section ST ₃ is specified, the distance y from the zero-phase non-power source end T ₃ to the failure point may be obtained using the formula (22), but using the current-voltage data of the zero-phase non-power source end T _2. It can also be oriented. A more reliable result can be obtained by comparing both orientation results.

When locating the fault point in the section ST ₃ using the current-voltage data of the zero-phase non-power source terminal T ₂ , the equation corresponding to the equations (4) and (5) in the line of FIG. 4 is ΔI ₀₁ = (D ₂ y / D) I _0f (23) ΔI ₀₂ = (d ₁ y / D) I _0f (24) ΔI ₀₃ = [1- (d ₁ + d ₂ ) y / D] I _0f (25) Become. However, y is the distance from the zero-phase non-power source terminal T ₃ .

Therefore, the distance y from the zero-phase non-power source terminal T ₃ at the failure point can be obtained from ρ in the equation (19) and this equation (24) by y = ρD / d ₁ (26) it can. However, y ≦ d ₃ . When the section T ₁ S is specified (see FIG. 5), the current / voltage data of either the zero-phase non-power source terminal T ₂ or the zero-phase non-power source terminal T ₃ can be used for orientation. Since there is symmetry, only the case of locating using the current-voltage data of the zero-phase non-power source terminal T ₂ will be described.

In the line of FIG. 5, the equations corresponding to the equations (4) and (5) are: ΔI ₀₁ = [1- (d ₂ + d ₃ ) z / D] I _0f (27) ΔI ₀₂ = (d ₃ z / D) I _0f (28) ΔI ₀₃ = (d ₂ z / D) I _0f (29). However, z is the distance from the zero-phase power source end T ₁ .

Therefore, the distance z from the zero-phase power supply terminal T ₁ at the failure point can be calculated from ρ in the equation (19) and this equation (28) by z = ρD / d ₃ (30) . However, z ≦ d ₁ . As described above, ρ is calculated based on the current-voltage data at the zero-phase non-power source terminal T ₂ or T ₃ and is applied to the formula to calculate the distance z from each terminal T ₁ , T ₂ , T ₃ to the fault point. ，
x, y can be obtained.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION

(a) In the following, when applied to a 2-terminal parallel 2-line transmission line,
Embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 6 shows a general 2-terminal parallel 2-line transmission line 1
FIG. 3 is a diagram in which a fault point calculating device 2 using the fault point locating method according to the present invention is connected, in order to detect the zero phase current I ₀₂₁ of the line 1L from the residual circuit at the zero phase non-power source terminal T _2. Current transformer CT ₁ provided in three phases, and current transformer CT ₂ provided in three phases for detecting zero-phase current I ₀₂₂ of line 2L.
And a voltage transformer PT for detecting the zero-phase voltage V ₀₂ of the busbar.

The fault point calculation device 2 includes current transformers CT ₁ and CT.
Zero-phase currents I ₀₂₁ , I detected by the residual circuit _2
022 and zero phase voltage V detected by the transformer PT
An input unit 3 that takes ₀₂ as an input and converts them into voltage signals of a predetermined level, a sample hold unit 4 that samples at a predetermined electrical angle, and an A / A that converts the voltage signal from the sample hold unit 4 into digital data. D conversion unit 5,
It is detected that a ground fault has occurred in the two parallel lines based on the data memory 6 that stores the digital data converted by the A / D converter 5 and the zero-phase voltage V ₀₂ detected by the instrument transformer PT. If there is an input of a ground fault detection signal from the ground fault detection unit 7 and a ground fault detection signal from the ground fault detection unit 7, zero phase is detected based on the current data and voltage data of the lines 1L and 2L stored in the data memory 6. a fault point orientation section 8 for calculating the distance from the non-power end T ₂ to fault point, displays for displaying information such as the distance to the fault point from the zero-phase non-power terminal T ₂ calculated by the fault point orientation section 8 And a part 9.

The operation of the fault point calculation device 2 having the above configuration will be described based on the fault examples shown in FIGS. In FIG. 1, the failure occurs at one point on one line, and that point is the zero-phase non-power source terminal T.
The distance is ₂ to x. The zero-phase currents and zero-phase voltages of the lines 1L and 2L detected by the residual circuits of the current transformers CT ₁ and CT ₂ are converted into voltage signals of a predetermined level at the input section 3. The voltage signal of the predetermined level is converted into digital data at a predetermined sampling period in the sample hold unit 4 and the A / D conversion unit 5, and the data memory 6
Be taken into.

On the other hand, the ground fault detector 7 is connected to the lines 1L and 2
Based on the zero-phase current data and zero-phase voltage data of L, a well-known method (for example, the occurrence of a ground fault is detected by the level of the zero-phase voltage, and the failure line is detected according to the phase relationship between the zero-phase voltage and the zero-phase current of each line). The occurrence of a ground fault is detected by (determining). When the fault point locating unit 8 knows that a fault has occurred, it reads the current data and voltage data stored in the data memory 6 to obtain the line-to-line differential current ΔI ₀₂ = I ₀₂₁ -I ₀₂₂ , and this and zero. Using the phase voltage V ₀₂ , ρ = V _0n · | ΔI ₀₂ | / I _0n · | V ₀₂ | Here, I _0n is a zero-phase current of the system at the time of a complete ground fault, and V _0n is a zero-phase rated voltage of the system, both of which are given as system-specific constants.

The fault point locating unit 8 further uses this ρ to find the distance x from the zero-phase non-power source terminal T ₂ to the fault point by the equation x = d (1-ρ). The obtained orientation result is displayed on the display unit 9. (b) Next, when applied to a 3-terminal parallel 2-line transmission line,
Embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 7 shows a three-terminal parallel two-line power transmission line 1a,
FIG. 3 is a diagram in which a fault point calculation device 2 using the fault point locating method according to the present invention is connected, and a zero phase non-power source terminal T ₂ has three phases for detecting a zero phase current I ₀₂₁ of a line 1L from a residual circuit. Current transformer CT ₁ provided in the line and the zero-phase current I _{022 of the} line 2L.
A current transformer CT ₂ provided in three phases for detecting the voltage and an instrument transformer PT for detecting the zero-phase voltage V ₀₂ of the busbar are provided.

The fault point calculation device 2 includes current transformers CT ₁ and CT.
Zero-phase currents I ₀₂₁ , I detected by the residual circuit _2
022 and zero phase voltage V detected by the transformer PT
An input unit 3 that takes ₀₂ as an input and converts them into voltage signals of a predetermined level, a sample hold unit 4 that samples at a predetermined electrical angle, and an A / A that converts the voltage signal from the sample hold unit 4 into digital data. D conversion unit 5,
It is detected that a ground fault has occurred in the two parallel lines based on the data memory 6 that stores the digital data converted by the A / D converter 5 and the zero-phase voltage V ₀₂ detected by the instrument transformer PT. If there is an input of a ground fault detection signal from the ground fault detection unit 7 and a ground fault detection signal from the ground fault detection unit 7, zero phase is detected based on the current data and voltage data of the lines 1L and 2L stored in the data memory 6. a fault point orientation section 8 for calculating the distance from the non-power end T ₂ to fault point, displays for displaying information such as the distance to the fault point from the zero-phase non-power terminal T ₂ calculated by the fault point orientation section 8 And a part 9.

The operation of the fault point calculation device 2 having the above configuration will be described based on the fault example of FIG. 3, FIG. 4 or FIG. In FIG. 3, the failure occurs at one point on one line, and that point is at a distance x from the zero-phase non-power source terminal T ₂ . In FIG. 4, the failure occurs at one point on one line, and that point is a distance y from the zero-phase non-power source terminal T ₃ . In FIG. 5, the failure occurs at one point on one line, and that point is a distance z from the zero-phase power source terminal T ₁ .

The zero-phase currents and zero-phase voltages of the lines 1L and 2L detected by the residual circuits of the current transformers CT ₁ and CT ₂ are converted into voltage signals of a predetermined level at the input section 3. The voltage signal of the predetermined level is supplied to the sample hold unit 4,
The A / D converter 5 converts the digital data into digital data at a predetermined sampling period and stores the digital data in the data memory 6.

On the other hand, the ground fault detector 7 is connected to the lines 1L and 2
The occurrence of a ground fault is detected by a known method based on the zero-phase current data and zero-phase voltage data of L. When the fault point locating unit 8 knows that a fault has occurred, it reads the current data and voltage data stored in the data memory 6 to obtain the line-to-line differential current ΔI ₀₂ = I ₀₂₁ -I ₀₂₂ , and this and zero. Using the phase voltage V ₀₂ , ρ = V _0n · | ΔI ₀₂ | / I _0n · | V ₀₂ | Here, I _0n is a zero-phase current of the system at the time of a complete ground fault, and V _0n is a zero-phase rated voltage of the system, both of which are given as system-specific constants.

The fault point locating unit 8 further uses this ρ to calculate the distance x from the zero-phase non-power source terminal T ₂ to the fault point by the formula x = (1-ρ) D / (d ₁ + d ₃ ). calculate. However, d ₂ and d ₃ are zero-phase non-power source terminals T
₂ , line length from T ₃ to branch point; d ₁ is line length from power source end T ₁ to branch point; D = d ₂ d ₃ + d ₃ d ₁ + d ₁
It is d _2.

If x> d ₂ , that is, ρ <d ₁ d ₃ /
If D, the distance y from the zero-phase non-power source end T ₃ to the failure point
Can be calculated by the equation y = ρD / d ₁ . Further, the distance z from the zero-phase power source end T ₁ to the failure point can be calculated by the formula z = ρD / d ₃ .

The obtained orientation result is displayed on the display unit 9, so that the maintenance staff can know the location where the failure has occurred.

[0040]

As described above, according to the first aspect of the present invention, one point and one line ground fault of one line of a high resistance two-terminal parallel two-line power transmission line are set as zero points at the zero-phase non-power source end. Since it can be determined based on the phase current and zero phase voltage data, it is effective when the zero phase current and zero phase voltage data at the zero phase power source end cannot be obtained.

According to the second or third aspect of the present invention, one point and one line ground fault point of one line of the high resistance three-terminal parallel two-line transmission line are defined as zero-phase current and zero at the zero-phase non-power source end. Since it can be determined based on the phase voltage data, it is effective when the zero phase current and zero phase voltage data at the zero phase power source end cannot be obtained. Particularly, according to the invention of claim 2, it is possible to locate the fault point occurring in the branch at the zero-phase non-power source end.
According to the invention of (1), it is possible to locate a failure point that has occurred in a branch other than the branch of the zero-phase non-power source end (either the zero-phase power source end branch or the zero-phase non-power source end branch).

Also, in any of the first to third aspects of the invention, based on the zero-phase current and zero-phase voltage data at the zero-phase power source end when the zero-phase current and zero-phase voltage data are obtained at the zero-phase power source end. The reliability of the orientation result can be improved by comparing the orientation result with the conventional method.

[Brief description of drawings]

FIG. 1 is a zero-phase equivalent circuit diagram of a two-terminal parallel two-line power transmission line.

FIG. 2 is a zero-phase-difference current equivalent circuit diagram of the two-terminal parallel two-line power transmission line.

3 is an equivalent circuit diagram based on the zero-phase difference current of the three-terminal type parallel two-circuit transmission line when a fault point exists in the segment ST _2.

FIG. 4 is a zero-phase-difference current equivalent circuit diagram of the parallel two-line power transmission line of the same three-terminal system when a failure point exists in the section ST ₃ .

FIG. 5 is a zero-phase-difference current equivalent circuit diagram of the same three-terminal system parallel two-line power transmission line when a failure point exists in the section T ₁ S.

FIG. 6 is a circuit diagram showing a state in which a fault point calculation device that uses the fault point locating method according to the present invention is connected to a two-terminal parallel two-line transmission line.

FIG. 7 is a circuit diagram showing a state in which a fault point calculating device using the fault point locating method according to the present invention is connected to a 3-terminal parallel 2-line transmission line.

[Explanation of symbols]

1 2 terminal parallel 2 line power transmission line 1a 3 terminal parallel 2 line power transmission line 2 Fault point calculation device 3 Input section 4 Sample hold section 5 A / D conversion section 6 Data memory 7 Ground fault detection section 8 Fault point location section 9 Display Part PT Instrument transformer T ₁ Zero-phase power source terminal T ₂ , T ₃ Zero-phase non-power source terminal CT ₁ , CT ₂ Current transformer

Claims (3)

[Claims] 1. A method of locating a one-point, one-line ground fault point of one line of a high-resistance two-terminal (i, j) parallel two-line transmission line by using a zero-phase current at a zero-phase non-power source end. Then, the line difference current ΔI _0j is calculated based on the zero-phase current of each line of the zero-phase non-power source end j, the zero-phase voltage V ₀ of the zero-phase non-power source end j is calculated, and the variable ρ is set to ρ. = V _0n · | ΔI _0j | / I _0n · | V ₀ | (V _0n is the rated zero-phase voltage, I _0n is the ground fault current at the time of one-line complete ground fault), and the equation x = d (1-ρ ) (D is the line length) is used to determine the distance x from the non-power source end j to the failure point. 2. High resistance 3 terminal (i, j, k) system parallel 2 lines
Zero-phase non-power source for 1 point 1 line ground fault point of 1 line of transmission line
It is a method of locating by using the zero-phase current at the end, and the difference between both lines is determined based on the zero-phase current of each line at the zero-phase non-power source end
Current ΔI_0jTo calculate the zero-phase voltage V of the zero-phase non-power source terminal j₀And calculate the variable ρ as ρ = V_0n・ | ΔI_0j| / I_0n・ ｜ V₀| (V_0nIs the rated zero-phase voltage, I_0nIs a one-line complete ground fault
Flow), and the equation x = (1−ρ) D / (d_i+ D_k) (D_jIs the line length from the zero-phase non-power source end j to the branch point;
d_i, D_kIs the terminal i, k other than the zero-phase non-power source terminal
Line length to the junction; D = d_jd_k+ D_kd_i+ D
_id_j) The distance x from the non-power source end j to the failure point
A method for locating a fault, which is characterized in that 3. High resistance 3 terminal (i, j, k) system parallel 2 lines
Zero-phase non-power source for 1 point 1 line ground fault point of 1 line of transmission line
It is a method of locating by using the zero-phase current at the end, and the difference between both lines is determined based on the zero-phase current of each line at the zero-phase non-power source end
Current ΔI_0jTo calculate the zero-phase voltage V of the zero-phase non-power source terminal j₀And calculate the variable ρ as ρ = V_0n・ | ΔI_0j| / I_0n・ ｜ V₀| (V_0nIs the rated zero-phase voltage, I_0nIs a one-line complete ground fault
Flow), and the equation y = ρD / d_i (D_jIs the line length from the zero-phase non-power source end j to the branch point;
d_i, D_kIs the terminal i, k other than the zero-phase non-power source terminal
Line length to the junction; D = d_jd_k+ D_kd_i+ D
_id_j) To find the distance y from the other terminal k to the failure point
A fault location method characterized by the following.