JPS62177464A - Fault point locating system - Google Patents

Abstract

PURPOSE:To locate the distance to a fault point with high accuracy by calculating the distance to the fault point from a specific equation based upon the voltage and current of this terminal and the current of the opposite terminal. CONSTITUTION:The voltage at the installation point of a fault point locating device (FL) is decomposed into a sine and a cosine component based on the current at the FL installation point and an equation based upon a voltage drop component originating from a fault current is set and solved to find the distance (l) to the fault point. Therefore, the need for voltage information on the opposite terminal is eliminated, so transmission capacity from the opposite terminal is reducible and the distance to the fault point is located accurately without a measurement error due to fault point resistance nor a tidal current.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a fault point locating method E, which is a method for locating a fault point with high precision from current and voltage information at the own end of a power transmission line to be located. Concerning point orientation methods.

[Conventional technology]

Conventionally, this type of failure point locating method was developed using the
There was one shown in No. 50262.

FIG. 5 is an equivalent circuit diagram of a power system when a failure occurs to explain the conventional invention. In the figure, Ep and decoy are the power supply voltages at the p and Q ends, and Zgp and Zgq are the back impedances at the p and Q ends. , vp, VQ is the voltage at the p and Q ends, Ip,
IQ is p, the current flowing from the Q terminal to the fault point, Rt is the fault point resistance, ■ is the fault locator (hereinafter referred to as a fault locator, FL), Iz is the impedance from the FL setting point to the fault point, and β is Distance from the FL installation point to the late camp point! , Z indicates the impedance per unit length of the transmission line. (L-g
) Z is the impedance from the failure point to the Q end, and L is the mouth end and Cn.

Indicates the distance between

Next, the concept of the conventional method will be explained.

According to FIG. 5, the following equation 11) is established.

Vp = 1ZIp + RF (ip + IQ)
-tll Therefore, the impedance up to the failure point can be found from the pressure and torrent information at the own end of one point where P″L is set, as follows (2
) is obtained.

Here, if RF is zero, the impedance up to the failure point l
Since Z is obtained, the distance @e to the fault point can be obtained by dividing by the impedance Z per unit length of the power transmission line. However, in the case of a failure in a complete system, an error occurs because the RF is not zero. Even if the current IQ could be obtained, it was not possible to apply extraction pressure because the RF failure condition was unknown (m).

For this reason, in the conventional invention, in order to eliminate this error, the fault point is located by obtaining voltage and current information at the mouth end (mouth end) and the other end (Q end).

That is, the above equation (1) is calculated from the voltage and current information at the end of the mouth, and the following equation (3) is calculated from the paper pressure current information at 9@.

vQ = (L −IZIQ + 1ff(ip +
IQ) - (3) By eliminating l(F) from equations (1) and (3), the distance e is calculated from equation (4) below.

[Problem that the invention seeks to solve]

The conventional fault point locating method is configured as shown in equation (4), so it is necessary to obtain voltage and current information from the own end and the other end, so the amount of information from the other end is large and the transmission capacity is large. There was a drawback.

This invention was made in order to eliminate the above-mentioned drawbacks, and eliminates the need for voltage information of the other end, and the voltage information of the own end,
The purpose of this invention is to provide a fault point locating method that can locate the distance to a fault point with high precision using only current information and current information at the other end.

[Means for solving problems]

The fault location method used in this investigation is to decompose the voltage at the FL setting point into a sine component and a cosine component using the current at the FL setting point d as a reference, and to create simultaneous equations by equating the voltage drop component due to the fault current. By solving this, the distance to the failure point can be found.

[Effect]

In the method of this invention, two equations are established by obtaining two quantities for the sine component and cosine component of the voltage at the FL installation point, so it is possible to locate with high accuracy even without voltage information at the other end. I can do it.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

(Fig. 1) Here, (1) is the upper pressure Vp at the FL installation point.
(Circuit for calculating the absolute value of D, (2) is the current at the FL installation point■
A circuit that calculates the absolute value of p, (3) a circuit that calculates the phase difference θ between Vp and Ip, and (4) a subtraction circuit that calculates lip ILl.
=I111, (5) is a circuit that calculates the phase difference φ1 between 1p and I, (6) is a circuit that calculates the phase difference δ between lp and the current IQ at the other end, and (7) is an adder circuit that calculates lIQ+I.
The circuit for calculating Ll=lI21, (8) is ip and engineering 2
(9) is a circuit that stores the current IL flowing in the power system E when no fault has occurred; (4) is an arithmetic circuit; 11sin(θ-φ1)+l2st
n(θ−a+φ2) (a circuit that can claim this value,
Uυ is an arithmetic circuit, I, sin (a-φt) + l
2sin (a - l + φ2) (a circuit that can be used to specify this value, where α is the line angle of the transmission line and the impedance per unit length Z = r + jx) A circuit that divides AIVpl by BZllpl; This shows the terminal that outputs the distance from the point of error to the point of failure.

Next, the concept of the present invention will be explained.

From the equivalent circuit diagram of the power system at the time of failure in Figure 2, FL
The voltage Vp at the installation point is the voltage drop component 1ZIp of the impedance 4Z up to the fault point due to the current jp at the FL installation point, and the current (I!
+, I2) due to voltage drop component RF(1+ + 1
2) is added.

Here, the currents IP and IQ at the own end and the opposite end are (14) The current IL flowing when there is no fault in the power system
(As shown in Figure 8, the power supply Ep at the p end and &gE at the Q end.
If there is a phase difference in Q, the total impedance of the power system Zgp +LZ + Z due to the potential difference of Ep-EQ
The current divided by gQ flows as tidal current It)I
When this fault occurs, the increment flowing into the fault point resistor RF is ¥4L a
It (P end side) and 1x (Q end side) are added and can be expressed as Ip=Il+IL and IQ=I2-IL.

Therefore, since Ip, IQ, and IL are known values, it is possible to calculate the bottle distribution and flow rate. Furthermore, the phase difference φ between Ip and 11, the phase difference φ2 between IQ and I2, and the phase difference a between Ip and IQ can also be calculated.

JJ, upper 0') Kotokara Vp=nZIp+RF (1
1+Iv) It can be shown as shown in FIG. In the figure, α is the line angle of the power transmission line, and the impedance per unit length Zwr + j x G, a = jan-1 (-
, ), θ is the phase difference between Vp and Ip, φl is the phase difference between Il and Ip, and δ-φ2 is the phase difference between I2 and 1p, all of which indicate phase angles with Ip as a reference.

Kura, from Figure 4, the following 15 are obtained from the sine and cosine components of Vp.
), (Equation 62 holds true.

iZ l I p lsmα+RF l l 111s
+nφt+l I21sln (δ−φ2))=l
Vp 1su>θ15) 11 1p 1cOsα+Rh'(l l1lcosφ
1+l Iz Ic0s(J-φz)1=l V
p Icesθ □(6)+57
, +61 is rewritten as a determinant, it becomes the following equation (7).

Therefore, the distance β to the failure point can be determined by the following equation (8).

However, 1Ill = IIp - Itl II21 = lIQ + LL + From this, if you obtain information on the current IQ of the other end, all the constants in the formula are known, so you can calculate the distance to the fault point even without voltage information on the other end. can do. Furthermore, since there is no fault point resistance RF in the equation, it can be seen that highly accurate location can be achieved without errors due to voltage drop components generated in the RF section.

In addition, although the above embodiment has been explained using a single phase, it goes without saying that it can be applied to an eight phase case.

Further, in the above embodiment, the distance to the fault point was determined by obtaining the fault point resistance RF, but it is clear from equation (7) that the fault point resistance RF can also be determined.

〔Effect of the invention〕

As mentioned above, this invention) is based on the voltage at its own end.

Since the distance to the fault point can be calculated using the current information and the current information of the other end, the transmission capacity from the other end can be reduced, and there is no distance measurement error caused by resistance at the fault point or influence of current flow, making it highly accurate. There is an effect that can be obtained.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing a fault point locating device according to an embodiment E of the present invention, Fig. 2 is an equivalent circuit diagram of a power system when a fault occurs taking into account power flow, and Figs. 8 and 4 are Figure 2 is a diagram depicting voltage and current components, and Figure 5 is an equivalent circuit diagram of the power system when a failure occurs.11) (2), (41, (7)... absolute device derivation circuit, (
3), t5), (8)...phase difference indexing circuit,
(9)...Memory circuit, 4-4...Arithmetic circuit, □□□
...output terminal, ring...fault point locating device. In addition, the same reference numerals in the drawings indicate the same or corresponding parts. Agent: Masuo Oiwa Figure 2, Figure 3E

Claims (1)

[Claims] In a fault point locating device that measures the distance to a fault point from voltage and current information in a two-terminal power transmission line having power supplies at both ends, l={|V_P|[|I_1|sin(θ−φ_1) +
|I_2|sin(θ−δ+φ_2)]}/{Z|I_
P|[|I_1|sin(α−φ_1)+|I_2|s
in(α-δ+φ_2)]} and l: Distance to the failure point |V_P|: Absolute value of the voltage at the installation point of the device |I_P|: Absolute value of the current at the installation point of the device |I_1|: |I_P −I_L|, I_P − Absolute value of I_L |I_2|: |I_Q+I_L|, I_Q − Absolute value of I_L I_P: Current at the installation point of the device at the time of failure I_Q: Current at the other end at the time of failure I_L: Power flow θ: I_P standard Phase difference of V_P φ_1 of I_P reference: Phase difference of I_1 of I_P reference φ_2: Phase difference of I_2 of I_Q reference δ: Phase difference of I_Q of I_P reference α: Line angle Z of power transmission line: Impedance per unit length of power transmission line A failure point locating method characterized by measuring the distance to the failure point by calculation.