JPH0668535B2 - Fault location method - Google Patents

Description

Detailed Description of the Invention TECHNICAL FIELD OF THE INVENTION

In order to ensure reliability of power supply, the present invention speeds up failure recovery by locating a failure point in a power transmission line based on the voltage amount and current amount at the time of an accident measured at both terminals of the transmission line. This is related to the fault location method that was planned.

[Prior art and its problems]

When a failure occurs in the system where the electric stations A and B are at both terminals of the transmission line as shown in FIG. 2, it is necessary to know the distance from the terminal A or B to the failure point F or the position of the failure point F. It is necessary and indispensable for subsequent repair work of defective parts. Therefore, in the conventional fault point locating method, the terminal devices A1 and B1 are connected to the A and B terminals.
Is provided, and the amount of voltage and current measured by this terminal device is
After D-converting, the data is transmitted to the central unit C, and the central unit C uses the phase difference between the data from each terminal to locate the fault point by vector operation according to a predetermined orientation formula. Such a conventional fault location method will be described with reference to a system potential diagram at the time of a fault shown in FIG. The amount of voltage measured at the terminal device A1, B1 during the transmission line faults _{A, B,} fault current amount _A, and _B, and the voltage of the fault point F _F, the distance from the terminal A to the fault point F alpha, When the distance from the B terminal to the fault point F is (1-α) and the transmission line impedance of unit length is, the following equation holds. _A- α _A = _F = _B- (1-α) _B (1) By solving for α from this equation (1), the distance to the fault point F can be obtained by the following equation. Where α
_A and (1-α) _B are voltage drops. However, since the right side of equation (2) is a vector operation, simultaneity is required between each terminal data. When the synchronous sampling method is used to achieve simultaneity between data, a synchronous signal transmission / reception circuit is required, and in the asynchronous sampling method, a phase difference correction circuit for sampling data by instantaneous failure detection is required. However, there is a drawback that the cost increases and the cost increases.

[Object of the Invention]

The present invention eliminates the need for simultaneity by performing the fault point calculation processing using the data from each terminal without using the phase difference between the data from each terminal, thus eliminating the need for simultaneity It is an object of the present invention to provide a failure point locating method that eliminates ancillary circuits such as, and reduces the cost of the device.

[Points of the Invention]

The point of the present invention is that the value obtained by subtracting the voltage drop due to the fault current from the potential of each terminal is equal at the fault point,
Taking advantage of the fact that the following equation (3), which is the absolute value of both sides of equation (1), holds in the same way, and find the position where the right and left sides of equation (3) are “0”, the failure point is Since it is included between these two positions, the position of the failure point is obtained by narrowing this range. | _A- α _A | = | _F | = | _B- (1-α)
_B |… (3)

Examples of the invention

In the following, assuming the failure of the 1-line 2-terminal system, the first
The fault location method according to the present invention will be described with reference to the explanatory diagram shown in the figure. In this system, the above equation (3) holds,
In the equation (3), the phase relationship between the data between the terminals A and B is unnecessary for the calculation, that is, the simultaneity between the data can be unnecessary. The measured amount of voltage _A at the fault point locating system in the terminal device A1, B1 according to the invention, _B and the current amount _{A, B}
The position of the fault point is obtained in the next step. [Step 1] In the formula (3), the following initial value α is set with the right side = 0 and the left side = 0.
_{Calculate A} and α _B. Since these α _A and α _B are located as shown in FIG. 1,
The fault point F exists within the range between α _A and α _B. [Step 2] Set α = (α _A + α _B ) / 2, and obtain V _FA = | _A −α _A |, V _FB = | _B − (1−α) _B |. That is, the potentials V _FA and V _FB at the intermediate position between α _A and α _B (shown as α in FIG. 1) are obtained. [Step 3] | V _FA −V _FB | is calculated from V _FA and V _FB obtained in step 2. When | V _FA −V _FB | ≦ ε holds when the preset tolerance is ε, α (= α _A + α) obtained in step 2
_B / 2) is the orientation result. That is, in FIG. 1, the position where | V _FA −V _FB | = 0 is the failure point position F, so if | V _FA −V _FB | is within the allowable error ε, α is regarded as the failure point position. It is possible. On the other hand, when | V _FA −V _FB |> ε holds, α does not fall within the fault point position F, so the routine proceeds to the next step 4. [Step 4] The following processing is performed according to the sizes of V _FA and V _FB . ( _B ) When V _FA > V _FB , α = new α _B. (B) When V _FA <V _FB , α = new α _A. After performing such processing, the process returns to step 2. In the case of FIG. 1, since V _FA > V _FB , α in FIG. 1 is regarded as new α _B, and in step 2, α ′ = (α _A + new α _B ) / 2 is set, and so on. Perform processing. The new α, that is, α ', is in the position shown in FIG. 1, but at the position of α', it is determined in step 3 that | V _FA −V _FB |> ε, and in step 4, V _FA <V _FB . So α ′ = α
After typing _A , go back to step 2 again. In step 2, new α, that is, α ″ = (new α _A + new α _B ) / 2, and the same processing is performed. By repeating such processing, the range of α _A and α _B is 1/2 method. Then, the position of | V _FA −V _FB | ≦ ε is finally obtained. Although the case of failure of the first line 2 terminal system has been described in the above description of the embodiment, the present invention in place of the aforementioned equation (3) in the case of the present invention can be applied to parallel two-circuit transmission line parallel two-circuit transmission _{line, |. a -α A1L -α m} A2L | = | F | = ｜ _B
-(1-α) _B1L − (1-α) _{m B2L} | ... (4) holds. In equation (4), _A1L and _B1L are the current of one line (one line), _A2L and _B2L are the other lines (two lines of current), and _m is the mutual impedance between the lines. If the processing of steps 1 to 4 described above is performed using this equation (4), it is possible to locate the fault point position.

【The invention's effect】

According to the present invention, since the fault point locating operation is performed only by the magnitude (absolute value) without using the phase difference between each terminal data, simultaneity becomes unnecessary, and an auxiliary circuit such as a synchronizing signal transmitting / receiving circuit is provided. Can be eliminated.

[Brief description of drawings]

FIG. 1 is a diagram for explaining a fault point locating system according to the present invention, FIG. 2 is a schematic configuration diagram of a fault point locating device in one line and two terminal system, and FIG. A potential system diagram is shown. A1, B1 ... Terminal device, C ... Central device, _RF ... Fault point resistance, F ... Fault point position.

Claims (1)

[Claims] 1. A fault point locating method, characterized in that terminal devices are installed at both terminals of a power transmission line, the voltage amount and the current amount at each terminal are measured, and the fault point position is determined by the following steps. (A) A step of obtaining a distance at each terminal until the value obtained by subtracting the voltage drop amount based on the current amount measured at the own terminal from the voltage amount measured at the own terminal becomes “0”. (B) A step of obtaining an intermediate position between two distances based on the distance obtained in step (a) or the distance replaced in step (d) below. (C) At each terminal, the step of obtaining the absolute value of the value obtained by subtracting the voltage drop amount to the intermediate position obtained in step (b) from the voltage amount measured at the terminal itself. (D) Find the difference between the two absolute values found in step (c). If this difference is less than the set value, go to step (b)
The step of considering the intermediate position obtained in step 2 as a failure point and replacing the intermediate position at this time with the distance in step (b) on the smaller absolute value side and moving to step (b).