JPH01165976A - Locating apparatus of faulty point of multiterminal power transmission line - Google Patents

Abstract

PURPOSE:To reduce an error and thereby to enable the precise location of a faulty point, by inputting the result of location on the non-supply terminal side and by comparing it with the result of location on the supply terminal side in respect to a distance to a branch point. CONSTITUTION:In a faulty point locating apparatus 6 provided on the supply terminal side of a transmission line 1 of three-terminal parallel two circuits which is made to branch at a branch point 1a positioned at a distance l1 from a power station A being a supply terminal, an arithmetic element 2 calculates a located value XA of a faulty point by a prescribed location formula, based on a zero-phase current of current transformers CT1 and CT2 for detecting the zero-phase current which are provided on the power station A side. Another faulty point locating apparatus 3 is provided on the side of a power station B which is a non-supply terminal. An input mans 5 inputs to a judging means 4 the result XB of location which is transmitted from the locating apparatus 3. The judging means 4 receives as inputs the result XA of location sent from the arithmetic element 2, a value of the distance l1 of the transmission line from the power station A to the branch point, etc., comparing the result XA of location from the arithmetic element 2 with the distance l1 of the line and adopting the result XA of location of its own when XA>=l1, while adopting the result XB of location of the locating apparatus 3 when XA<l1.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a fault point locating device for a multi-terminal power transmission line for accurately determining the distance to a fault point of a multi-terminal power transmission line.

B2 Summary of the Invention The present invention is a fault point locating device for a multi-terminal power transmission line installed at the power end of a power transmission line in a parallel two-circuit multi-terminal system, which enables the input of the location results of the non-power end, and the self-location results. By comparing the distance to the branch point and adopting the own location result or the non-power end location result depending on whether it is closer or farther than the branch point, it is possible to locate the fault point with high accuracy. It is something.

C4 Prior art There have been various fault point locating methods for finding fault points in power transmission lines.
The proposal was made in No. 057 or Japanese Patent Application No. 60-238953. These proposals are based on voltages measured at an electrical station at one end of a power transmission line.

The fault point is located by calculation using current and known line constants, and the above-mentioned electrical station has the feature that it can be applied to both power supply terminals and non-power supply terminals.

However, when locating fault points such as ground faults using a fault point locating device at the power source end (A substation) of a parallel two-circuit power transmission line as shown in Figure 4, the following equation with higher accuracy is used. It was done using

Here, Xo is the distance from A substation to the fault point, and ρ is A
The distance from the substation to the B substation at the non-power end, 1o+, is 1
The return zero-sequence current, IO2, is the two-bus zero-sequence current.

Equation (1) is derived from the fact that Equations (2) and (3) hold true in line 1 and line 2 of the two parallel lines in FIG.

Line 1; VQA= (+0120 + +02Z.)
XO+VoF(2) Line 2; VOA-(+02Z0
+ Io+Zm)Xo+ Io2Zo(QX o)+(
IoJo 2L2Z1Xρ-Xo) +VOF Here, VOA is the A substation bus zero-sequence voltage, Zo is the zero-sequence impedance per unit distance (IKm) of the transmission line, Z, 1t
Similarly, J is the zero-sequence mutual impedance per unit distance of the transmission line, and VQF is the zero-sequence voltage at the fault point.

D Problems to be Solved by the Invention However, when the failure point locating device in the prior art is applied to a three-terminal system power transmission line as shown in FIGS. There are cases where the error becomes very large.

The present invention was created in order to solve the above problems, and provides a fault point locating device for multi-terminal power transmission lines that can reduce errors and accurately locate fault points when applied to multi-terminal power transmission lines. The purpose is to provide.

E. Means for Solving the Problem The configuration of the failure point locating device for multi-terminal power transmission lines to achieve the above objective is as follows: In a fault point locating device installed at the power source end of a wire, means for inputting the location value transmitted from another fault point locating device installed at the non-power end, and if the own location value is less than or equal to the distance ρ. The present invention is characterized by comprising a determining means that employs its own orientation value, and employs the orientation value of the non-power terminal when the distance e1 is exceeded.

F. Effect The present invention provides that when the fault point location formula for two parallel circuits is applied to a multi-terminal parallel two circuit having branches, the location result on the power supply end side is determined to be the fault point depending on the line distance to the branch point. Focusing on the fact that if the distance is less than that distance, the accuracy is high, and if it exceeds it, the error becomes large.The results of the orientation on the non-power end side are input, and the orientation results on the power end side and the distance to the branch point are compared to determine the highest error. The orientation result on the side that is estimated to be smaller is adopted.

G. Examples Examples of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention. This embodiment (") will be explained by taking as an example a case where it is applied to a power transmission line 1 with three terminals and two parallel circuits branching at a branch point 1a.
, CT', is a current lance for detecting zero-sequence current provided on the Δ substation side; 2 is a calculation unit that calculates the oriented value XA of the fault point using the offset locating formula described later based on the zero-sequence current, etc.; 3 is the fault point locating device installed on the B substation side, 4 is the determination means, and 5 is the location result X transmitted from the fault point locating device 3.
This is an input means for inputting B into the determination means 4. Judgment means 4
(The orientation result XA from the J1 calculation section 2 and the power transmission line distance ρ1 from the A substation to the branch point 1a are input, and the orientation result XA of the calculation section 2 is compared with the indicated track distance . ,XA
If ≧ρ1, use own orientation result XA, and if XA<0.1
If so, it has a function of employing the location result XB of the failure point location device 3. Substation A is the power supply end, and transmission line 1 branches into substation B and substation C at branch point 1a, and substation B and C
The substation is the non-power end. B substation fault location device 3
Transmission of the orientation result 21 Judgment means 4. Input means 5. Karen 1-1-Lance C'1) 1.0 'I' 2nd grade is
This constitutes a fault point locating device 6 on the substation A side.

The operation of the embodiment configured as above will be described.

FIGS. 2 and 3 are explanatory diagrams for this purpose.

Figure 2 shows the transmission line 1 of the above-mentioned parallel two-circuit three-terminal system at point F, where the line distance ρ from the A substation (hereinafter referred to as power supply end A) to the branch point 1a, and the following line distance Xo. This shows a case where a ground fault has occurred. In the figure, 12
2 is the line distance between branch point 1a and B substation, ρ3 is the line distance between branch point +a and C substation, Io+ is 1 bus zero-sequence current, I (l is 2 bus zero-sequence current, I 02BI T
o2゜ is the two-bus zero-sequence current divided at the branch point, ■or the power supply end A bus zero-sequence voltage, VOF is the fault point zero-sequence voltage, Zo is the zero-sequence impedance per unit distance of transmission line 1, Z
Similarly, nl is the zero-sequence mutual impedance per unit distance.

” - In the system shown above, the location result XA' is obtained using the conventional fault point location formula (1) with the main line between substations A and B as follows: =8= On the other hand, the true value of the track distance to the fault point F is . When calculating, VoA-(I o+Zo+ T 02Z-)XO+VO
FVOA-(IO2ZO+Io+Znt)Xo+21
02(ZOZ,)'(ρ1Xo)+21opB(Zo
Since Z+n)L+Vol- holds true, the true value is X. Hato becomes. Therefore, the orientation error ΔXA'=XA'XO becomes. Here, especially ρ3>>+! 2, ΔXA'-〇ρ3<<Q, and there are cases where there is a very large error.

Figure 3 shows the line distance Q from substation A to branch point 1a for power transmission line 1 of the parallel two-circuit three-terminal system as in Figure 2.
Track distance X greater than 1. This shows the case where a ground fault occurs at point F. In the figure, ■o11+ indicates the 1-retrace zero-sequence current shunted at the branch point 1a, and the other symbols are the same as in FIG. 2. In the above system, the conventional fault point location formula (1) is used to locate the main line between substations A and B.
When A' is found, on the other hand, the true value of the track distance to the accident point F is X. VO8-(T o+Zo+I o2Zn)L4(I
0IBZO+I Q2BZm)'(Xo-ρ,) 10V. F VoA(I [12ZO+T o+Zm)L+(I o
2BZo+l o2nZ1n) (X o−ρ, )+21
E12+1(Z o−Z ,,)−(ρ,+Q2−
Xo) 10v. Since F holds true, the true value is X. Hato becomes. Therefore, the orientation error ΔXA'-XA' Xo becomes. Here, especially the worst case is X. -121+
Considering ρ, 101=IO2 Therefore, if (23〉〉ρ2, ΔXA′ 蓓OQ3〈
<In the case of ρ2, it becomes ΔXA' - J2, and there are cases where there is a very large error.

Therefore, in this embodiment, in FIG. 2, this is substituted into equation (4), and in equation (6), 1+122+ρ3 is known, T O
12I 02 is a current transformer CT installed in the grid,
, CT2, the location can be determined using equation (6). In other words, the orientation result of the power supply terminal A is as follows, and the orientation error is ΔXA=XA X0=O.

Therefore, X as shown in Figure 2. If ≦121, a highly accurate orientation result XA can be obtained using equation (7). Conversely, if XA≦121, it can be estimated that XA is an accurate orientation result.

However, in Figure 3, equation (5) does not hold, so
A = Xo does not hold. In other words, no error occurs = 1
2-. Therefore, as shown in Figure 1, the orientation result XB of the non-power supply end B is transmitted to the power supply end A, and if the orientation result XA in equation (7) becomes XA>(!+, the error in XA is a dog. Assuming that, XB is adopted.In Figure 2, A and B
Even in this case, since substation B is a non-power supply terminal, it cannot be located using equation (1). If formula 1) is used, then the denominator becomes 0, so it becomes undefined. Therefore, the method of determining the impedance to the accident point as described in the previously proposed patent application No. 59-143057 or the patent application No. 60-238953 is used to determine the impedance, and this result is used as the XB.
shall be.

Note that the present invention is applicable to multi-terminal power transmission lines.

In the above example, if there is a fault point on the branch side of substation C, the orientation results at each non-power source end and the distance to the branch point are compared, and the orientation result closer to the non-power source end is used. It's okay. As described above, the present invention can be applied and implemented in various ways in accordance with its gist.

Effects of the F1 Invention As is clear from the above explanation, according to the fault point locating device for multi-terminal power transmission lines of the present invention, accurate location is possible even in parallel two-circuit power transmission lines in systems with three or more terminals. .・

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG.
FIG. 3 is an explanatory diagram of the operation of the above embodiment, and FIG. 4 is an explanatory diagram of the conventional locating means. 1...Power transmission line, 1a branch point, 4...Judgment means, 5...
- Input means, A - power supply end, B - non-power supply end, XA... own orientation result, XB non-power supply end orientation result.

Claims (1)

[Claims] In a fault point locating device installed at the power end of a power transmission line that branches into a parallel two-line multi-terminal system at a branch point at a distance l_1 from the power end, another fault installed at the non-power end means for inputting the orientation value transmitted from the point location device; and if the own orientation value is less than or equal to the distance l_1, the own orientation value is adopted, and when the said distance l_1 is exceeded, the orientation value of the non-power source end is adopted. A failure point locating device for a multi-terminal power transmission line, comprising: determination means.