JPH07270481A - Fault point locating method - Google Patents

Abstract

PURPOSE:To locate all types of fault mode and perform arithmetic operation without any need of synchronization at both line ends by setting the route length of a double terminal single transmission line and the impedance matrix thereof per unit length, and then measuring each phase voltage and current at the start and final ends of the line. CONSTITUTION:Double terminal single transmission line route length and the impedance matrix thereof per unit length are set to measure each phase voltage and current at the start and final ends thereof. Then, a scalar volume Im<V1, I1> and Im<ZI1, I1> are calculated on the basis of a voltage vector V1=(V1a, V1b, V1c)' and a current vector I1=(I1a, I1b, I1c)' appearing at the start end upon occurrence of a fault, where Im stands for an imaginary number, <> for an scalar product and ()' for vector inversion. Furthermore, a scalar volume Im<V2, I2> and Im<ZI2, I2> is calculated on the basis of a voltage vector V2=(V2a, V2b, V2c)' and a current vector I2= (I2a, I2b, I2c)' appearing at the final end upon occurrence of a fault, thereby locating a fault point.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fault point locating method applicable to any fault in a two-terminal single-line power transmission line.

[0002]

2. Description of the Related Art Conventionally, a so-called 44S relay system has been used as a system for locating a short-circuit fault point in a two-terminal single-line power transmission line. In this method, the line voltage and line current are measured at the power transmission end, and the line voltage at the time of failure is divided by the line current to obtain the impedance from the power transmission end to the failure point. This is a method of obtaining the distance to the failure point by dividing by the impedance per length, which is described in detail in, for example, Japanese Patent Application Laid-Open No. 4-36669 as "prior art".

The results of a short circuit between the a-phase and the b-phase are as follows:
If the a-phase voltage at the power transmission end is V _a , the b-phase voltage is V _b , the a-phase current is I _a , and the b-phase current is I _b , the distance x from the power transmission end to the failure point is Im [(V _a -V _b) obtained by / (I _a -I _b)] = XIM [Z _1] (1). Where Im represents the imaginary part and Z ₁
Is the positive phase impedance per unit length.

Also, due to a ground fault in a two-terminal single-line transmission line
The ground fault distance relay 44G
A fault location method is used. This method is
, The phase voltage and the phase current are measured, and the phase of the ground fault current is measured.
And zero-phase current I at the transmission end ₀Assume the phases of are equal
Then, the distance x to the failure point is calculated by the following expression Im [V_aI₀ ^*] = XIm [{Z₁I_a+ (Z₀-Z₁) I₀} I₀ ^*[2] is a method for obtaining it. For example, Japanese Patent Laid-Open No. 4-31967
It was introduced in detail in "No. 4" as "conventional technology".
It In addition, * represents a complex conjugate, and Z₀Is per unit length
Zero-phase impedance.

[0005]

As described above, since the equations to be applied are different between the case of the short-circuit fault point and the case of the ground fault, the fault aspect is first identified as the premise for calculating the fault point. There is a need to. Therefore, the present invention solves the above-mentioned technical problem and utilizes the information of the other end together with the own end in the fault location in the two-terminal single-line power transmission line.
It is an object of the present invention to provide a fault point locating method capable of locating all failure patterns and capable of performing calculations without synchronizing both ends.

[0006]

A fault location method according to claim 1 for achieving the above object is a line length d of a two-terminal single-line power transmission line, and an impedance matrix Z per unit length.
By setting each phase voltage V _1a , V _1b , V _1c at each end, each phase current I _1a , I _1b , I _1c and each phase voltage V _2a , V _2b , V _2c , each phase current I at the other end. _2a , I _2b , I _2c are measured, and a voltage vector V ₁ = (V _1a ,
V _1b , V _1c ) ′ and current vector I ₁ = (I _1a , I _1b ,
Based on I _1c ) ′, a scalar quantity Im <V ₁ , I ₁
>, Im <ZI ₁ , I ₁ > (Im is an imaginary part, <> is an inner product,
() 'Represents the transposition of the vector. ) Is calculated, and the voltage vector V ₂ = (V _2a , V _2b , V at the other end at the time of failure)
_2c ) ′ and current vector I ₂ = (I _2a , I _2b , I _2c ) ′
Based on, the scalar quantities Im <V ₂ , I ₂ >, Im <
ZI ₂ , I ₂ > is calculated, and based on the above calculation result,
This is a method of locating a failure point in a two-terminal single-line power transmission line regardless of the type of failure.

[0007]

[Action] Figure 1 is a circuit diagram of a two-terminal, single line transmission line to which the present invention is applied, each end as T _1, T _2, d ₁ from the terminal T _1, d ₂ (d ₁ from the terminal T ₂ It is assumed that a point up to + d ₂ = d) is an arbitrary intermediate point b, and a failure occurs at a position at a distance x from this point. Each phase voltage vector at the fault point (the term “vector” is omitted hereinafter) is written as (V _fa , V _fb , V _fc ) ′ = V _f, and each phase current at the fault point is (I _fa , I _fb). , I _fc ) ′ = I _f .

The voltage at the terminal T ₁ is (V _1a , V _1b , V _1c ) ′ = V ₁ The voltage at the terminal T ₂ is (V _2a , V _2b , V _2c ) ′ = V _{2 At the} terminal T ₁ The current is (I _1a , I _1b , I _1c ) ′ = the current at the I ₁ terminal T ₂ is (I _2a , I _2b , I _2c ) ′ = The impedance matrix per unit length of the I ₂ transmission line

[0009]

[Equation 1]

Write as From the above, the following relational expression is obtained. V_f= V₁-(D₁+ X) ZI₁ (3) V_f= V₂-(D₂-X) ZI₂ (4) I₁＋ I₂= I_f (5) Here, two vectors A = (A₁, A₂, A₃) ′,
B = (B₁, B₂, B ₃) ′ Inner product <A, B>, <A, B> = B₁ ^*A₁+ B₂ ^*A₂+ B₃ ^*A₃ 
(* Is a complex conjugate). For this inner product, the addition rule <A, (B + C)> = <A, B> + <A, C> holds. From equations (3) and (4), <V_f, I₁> = <V₁, I₁>-(D₁+ X) <ZI
₁, I₁＞ <V_f, I₂> = <V₂, I₂>-(D₂-X) <ZI
₂, I₂> Is obtained, and when these two expressions are added, <V_f, I_f> = <V₁, I₁> + <V₂, I₂>-[D₁<ZI₁, I₁> + D₂<ZI₂, I₂>]-X [<ZI₁, I₁>-<ZI₂, I₂>] (6) is obtained.

The left side of the equation (6) can be written as <V _f , I _f > = I _fa ^* V _fa + I _fb ^* V _fb + I _fc ^* V _fc (7) from the definition of the inner product. The impedance at the fault point may be considered as a resistance component, and in this case, <V _f , I _f > is a real number in any case. In other words, the <V _f, I _f> the imaginary part of _{Im <V f, I f>} = 0 (8). It will be proved by using FIGS. 2 to 6 that this relationship holds for any failure.

FIG. 2 shows the case of a one-line ground fault, and V_fa= I
_faR_faAnd I_fb= I_fc= 0, so <V_f, I_f> = I_fa ^*V_fa＋ I_fb ^*V_fb＋ I_fc ^*V_fc = I_fa ^*V_fa= I_fa ^*I_faR_fa= R_fa| I_fa｜²(Actually
Number). FIG. 3 shows a case of a two-wire ground fault, and V_fa= I_faR
_fa, V_fb= I_fbR_fbAnd I_fc= 0, so <V_f, I_f> = I_fa ^*V_fa＋ I_fb ^*V_fb = R_fa| I_fa｜²+ R_fb| I_fb｜²(Real number) FIG. 4 shows the case of a three-wire ground fault, V_fa= I_faR
_fa, V_fb= I_fbR_fb, V _fc= I_fcR_fcTherefore, <V_f, I_f> = I_fa ^*V_fa＋ I_fb ^*V_fb＋ I_fc ^*V_fc = R_fa| I_fa｜²+ R_fb| I_fb｜²+ R_fc| I_fc｜
²(Real number) FIG. 5 shows the case of 2-wire short circuit, V_fa= V_fn+
I_faR_fa, V_fb= V_fn＋ I_fbR_fb, I_fa= -I_fbAnd I
_fc= 0, so <V_f, I_f> = I_fa ^*V_fa＋ I_fb ^*V_fb = R_fa| I_fa｜²+ R_fb| I_fb｜²+ (I_fa ^*+
I_fb ^*) V_fn = R_fa| I_fa｜²+ R_fb| I_fb｜²(Real number) FIG. 6 shows the case of 3-wire short circuit, V_fa= V_fn+
I_faR_fa, V_fb= V_fn＋ I_fbR_fb, V_fa= V_fn＋ I_faR
_fa, I_fa＋ I_fb＋ I_fc= 0, so <V_f, I_f> = I_fa ^*V_fa＋ I_fb ^*V_fb＋ I_fc ^*V_fc = R_fa| I_fa｜²+ R_fb| I_fb｜²+ R_fc| I_fc｜
²(Real number) Therefore, we can prove that Eq. (8) holds.
It was

Taking the imaginary part of Eq. (6) in consideration of Eq. (8), the distance x to the fault point is

[0014]

[Equation 2]

Is calculated by When x ≧ 0, the failure point is on the terminal T ₂ side from point b, and when x ≦ 0, the failure point is on the terminal T ₁ side from point b (see FIG. 1). Im <V ₁ , I ₁ > = Im (I _1a ^* V _1a + I _1b ^* V _1b + I _{1c in the} equation (9).
^* V _1c ) Im <V ₂ , I ₂ > = Im (I _2a ^* V _2a + I _2b ^* V _2b + I _2c
^* V _2c ) represents the reactive power (real number) flowing from the terminals T ₁ and T ₂ , respectively. Also,

[0016]

[Equation 3]

When the relational expression Z ₁ = Z _s -Z _m Z ₀ = Z _s + 2Z _m is used, Z ₀ -Z ₁ = 3Z _m . Therefore, the equation (10) is expressed by Im <ZI ₁ , I ₁ > = Im [Z ₁ (| I _1a | ² + | I _1b | ² + | I _1c | ² )] + Im [Z ₀ −Z ₁ ] 3 | I ₁₀ | ² (11), and it can be seen that all terms of Im <ZI ₁ , I ₁ > are scalar quantities. _{Similarly, Im <ZI 2, I 2} > = Im ^{_{[Z 1 (| I 2a | 2}} + | I 2b | 2 + | I 2c | 2) ] + Im [Z ₀ -Z _1] 3 | I ₂₀ | ² (12), and all terms of Im <ZI ₂ , I ₂ > are also represented by scalar quantities. Therefore, it is not necessary to perform vector calculation based on the measured amount of each terminal, and synchronization is not necessary.

If d ₁ = d ₂ = d / 2 in the equation (9),

[0019]

[Equation 4]

[0020]

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The fault location method of the present invention will be described in detail below with reference to the accompanying drawings. Note that the same reference numerals are used for the same elements as those in FIG. 1 described above. FIG. 7 is a diagram showing a two-terminal single-line power transmission line and a failure point calculation device applied to the failure point locating method according to the present invention. A two-terminal single-line power transmission line (hereinafter abbreviated as a two-terminal system) L is , Terminal T ₁ , terminal T
Each of ₂ has a transformer that is grounded by a resistor. The failure point calculation device 1 is arranged on the terminal T ₁ side, but the calculation device 2 for measuring a current and a voltage and performing a predetermined calculation is also arranged on the terminal T ₂ side.

The fault point calculating device 1 includes a current transformer C connected to the a-phase, b-phase and c-phase of the line L on the terminal T ₁ side.
It includes an instrument transformer PT which is connected to T and a bus on the terminal T ₁ side and detects each phase voltage. The fault point calculating device 1 further includes measured phase voltages V _1a , V _1b , V _1c ,
Auxiliary transformer 11 for converting each phase current I _1a , I _1b , I _1c into a voltage signal at a predetermined ratio, and a sample hold for sampling the voltage signal converted by the auxiliary transformer 11 at every predetermined electrical angle (for example, 30 degrees) Implicit which is a scalar quantity based on the digital value converted by the circuit 12, the A / D converter 13, the receiving terminal 14 that receives the output data at the terminal T ₂ through light, wireless, etc., and the A / D converter 13.
A CPU that calculates V ₁ , I ₁ >, Im <ZI ₁ , I ₁ >,
These quantities Im <V ₁ , I ₁ >, Im <ZI ₁ , I ₁ >, and Im <V ₂ , I ₂ >, Im <ZI ₂ , which are scalar quantities at the terminal T ₂ read through the receiving terminal 14. I ₂
>, A data memory 15 for storing>, a zero-phase voltage / current, a positive-phase voltage / current, and a negative-phase voltage / current to detect a short-circuit fault or a ground fault. ), And a settling value memory 17 storing the values of the impedance matrix Z per unit length of the two-terminal system L as settling values.

The display unit 18 displays information such as a failure position calculated by the CPU. Also, the terminal T ₂
Are the phases a, b and c of the two-terminal system L at the terminal T ₂ .
Current transformer CT connected to the phase, and transformer PT for measuring the voltage of each phase connected to the bus on the terminal T ₂ side, voltage of each phase measured by the current transformer CT and the transformer PT for meter .Im <V ₂ , I ₂ >, which is a scalar quantity based on the current,
An arithmetic unit 2 for arithmetically operating Im <ZI ₂ , I ₂ > and transmitting it via radio, light, etc. is provided.

The arithmetic unit 2 has a sample hold circuit for sampling the data of each phase voltage / current and an A / D for digitally converting the data, like the fault point calculating unit 1.
Although a converter is built in, the sampling hold circuit and the sample hold circuit 12 of the failure point calculation device 1 are not characterized in that sampling synchronization is provided.

Explaining this in detail, in the conventional case,
For data transmission between the computing device 2 and the fault point calculation device 1.
For example, the sampling that occurs during data transmission.
A so-called SP synchronization control technique that accurately measures and corrects the time difference
Surgery (reciprocating the signal between both stations, the time it took to make the round trip)
A technique to measure the difference in sampling time and obtain the sampling time difference. Mitsubishi Electric
Technical report Vol.63, No.8, 1989, p.p.27-31)
If so, it is possible to accurately synchronize sampling of data.
Didn't come However, in the present invention, it is a scalar quantity.
Im <V₁, I₁>, Im <ZI₁, I₁>, Im <V₂, I
₂>, Im <ZI ₂, I₂Do an operation with> as an element
Therefore, it is not necessary to accurately synchronize the sampling of data.
Instead, it has the advantage of simply sending the data.

The operation of the failure point calculation device 1 is as follows. When the failure detection unit 16 detects any one of a ground fault, a short circuit, and a disconnection, the CPU responds to a failure point calculation command signal (regardless of the type of failure) from the failure detection unit 16 and sets a set value memory. Impedance Z stored in 17 and Im <V ₁ , I stored in the data memory 15
₁ >, Im <ZI ₁ , I ₁ >, Im <V ₂ , I ₂ >, Im <Z
The calculation of the equation (13) is performed using I ₂ and I ₂ > as elements to calculate the distance x from the intermediate point b to the failure point.

The present invention is not limited to the above-described embodiment. For example, arithmetic devices are installed at the terminals T ₁ and T ₂ , respectively, to transmit data, and from the terminal T ₁ to the terminal T _2. It is also possible to install the failure point calculation device 1 at a place far away from. Other various modifications can be made without departing from the scope of the present invention.

[0028]

As described above, according to the fault point locating method of the present invention, the voltage and current information at the self end and the other end is required, but it is not necessary to synchronize at each end, and the self end and Only the scalar quantity that can be measured at the other end can be used to locate the failure point regardless of the failure type. Therefore, the failure point can be specified, and the work of searching for the failure point can be performed with a small amount of labor.

[Brief description of drawings]

FIG. 1 is a circuit diagram of a two-terminal single-line power transmission line for explaining the operation of the present invention.

FIG. 2 is a diagram for proving that Im <V _f , I _f > = 0 in the case of a one-line ground fault.

FIG. 3 is a diagram for proving that Im <V _f , I _f > = 0 in the case of a two-wire ground fault.

FIG. 4 is a diagram for proving that Im <V _f , I _f > = 0 in the case of a three-wire ground fault.

FIG. 5 is a diagram for proving that Im <V _f , I _f > = 0 in the case of a two-wire short circuit.

FIG. 6 is a diagram for proving that Im <V _f , I _f > = 0 in the case of a three-wire short circuit.

FIG. 7 is a diagram showing a two-terminal single-line power transmission line and a fault point calculating device applied to the fault point locating method according to the present invention.

[Explanation of symbols]

 1 Failure point calculation device 2 Computing device L 2 terminal single line transmission line

Claims (1)

[Claims] 1. A line length d of a two-terminal single-line power transmission line and an impedance matrix Z per unit length are settled, and each phase voltage V _1a , V _1b , V _1c , and each phase current I _1a , I _1b at its own end. , I _1c and each phase voltage V _{2a at the} other end,
V _2b , V _2c , phase currents I _2a , I _2b , I _2c are measured, and a voltage vector V ₁ = (V _1a ,
V _1b , V _1c ) ′ and current vector I ₁ = (I _1a , I _1b ,
Based on I _1c ) ′, a scalar quantity Im <V ₁ , I ₁
>, Im <ZI ₁ , I ₁ > (Im is an imaginary part, <> is an inner product,
() 'Represents the transposition of the vector. ) Is calculated, and the voltage vector V ₂ = (V _2a ,
V _2b , V _2c ) ′ and current vector I ₂ = (I _2a , I _2b ,
Based on I _2c ) ′, a scalar quantity Im <V ₂ , I ₂
>, Im <ZI ₂ , I ₂ >, and locating the fault point in the two-terminal single-line power transmission line based on the calculation result regardless of the type of fault.