JPH0618601A - Fault-point orienting apparatus - Google Patents

Abstract

PURPOSE:To obtain the stable and highly accurate orientation by separating an input circuit for synchronous control and an input circuit for operating the point for orienting a fault point, and always obtaining the orientation input under the synchronized state. CONSTITUTION:A current testing plug 1A and a voltage testing plug 2A, which are provided for the current transformer and the transformer at a terminal A, are separated from the secondary side with the primary sides being shorted or released in the test. The current, which is inputted from the plug 1A, is converted into the digital quantities in an A/D converter circuit 5A through an input converting circuits 2A1 and 3A2. The voltage, which is inputted from the plug 2A, is converted into the digital quantities in the A/D converter 5A through input converting circuits 4A1 and 4A2. The results are operated in a operating circuit 6A. The results of the operations and the data are sent into the corresponding terminals through an interface 7A. The data of the corresponding terminals are received. A terminal B is constituted as the terminal B, and only the contents of the operations in the operating circuits 6A and 6B are different. The terminal B acquires the data, sends the data into the terminal A, receives the synchronized control amount from the terminal A and performs the control so as to obtain a specified sampling timing. The operation circuit 6A continues the synchronous control operation when there is no fault. When a fault is detected, the operation is switched to a fault-point orienting operation. Thus, the sampling synchronization is continued to the time immediately before the occurrence of fault. Therefore, the stable orientation test can be performed.

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 device for locating a fault point by collecting voltage and current at each terminal of a transmission line.

[0002]

2. Description of the Related Art Conventionally, there are a surge receiving method, a pulse radar measuring method, an impedance measuring method, etc. as a fault point locating method for a transmission line. The former two require expensive communication equipment. On the other hand, the latter impedance measurement method does not require new equipment to obtain the input amount because it directly measures the voltage and current obtained from the transformer and the current transformer. However, if there is a fault resistance,
Since there is not only the current of its own terminal but also the current flowing from the other terminal at the failure point, the current phase angles of both do not necessarily become the same phase, which may cause a distance measurement error.
For this reason, the orientation method that takes in the voltage and current of all terminals of the transmission line and is not affected by the resistance of the fault point by using Kirchhoff's law is drawing attention, for example, Japanese Examined Patent Publication No. 57-5026.
No. 2 is proposed.

[0003]

The above-mentioned conventional method is
When there is no accident on the way, the voltage at each branch point is the same, and the voltage and current at all terminals connected to the branch point of the same transmission line are synchronized. It is premised on controlling to sample. Therefore, it is clear that the calculation accuracy of the branch point voltage in the state where there is no accident at all times requires a considerably high level. For that purpose, the full scale of the current input of the fault locator must assume the load current level of the transmission line. However, if an accident occurs in the power transmission line, a fault current that exceeds the load current naturally flows, and if it is used as it is for the fault location calculation, a large error will occur.
Furthermore, if the current input for fault location and the current input for the synchronous control are shared, it is necessary to input the voltage and current of the synchronized transmission line in order to synchronize the sampling of each terminal.
It is very difficult to input the amount of test electricity from the outside when conducting a test on site. That is, the asynchronous input is input to each terminal and the synchronization is lost. But that doesn't mean that you don't test. The present invention has been made in view of the above circumstances, in a fault point locating device that controls to simultaneously sample the electrical quantities of the terminals using the electrical quantities of the synchronized system, a large fault current flows. Also aims to provide a fault point locator capable of securing orientation accuracy and capable of orientation test with stable sampling synchronization.

[0004]

In order to achieve the above object, the present invention collects voltages and currents at a plurality of terminals of a transmission line and calculates and calculates a voltage drop from each terminal to a branch point. In the fault point locating device configured to automatically adjust the voltage and current collecting timings of the terminals so that the branch point voltages are equal by utilizing the fact that the branch point voltages are equal if there is no fault in the section, The first means for fetching the voltage and current for calculating the failure point, the second means for fetching the voltage and current for controlling the timing of collecting the voltage and current, and the first means for fetching And a third means for preventing the timing control by the second means when a failure is detected by voltage and current.

[Function] Since the input circuit for synchronous control and the input circuit for fault point location calculation are separated, it is possible to improve the orientation accuracy and at the same time obtain the test input of the orientation function under the condition of synchronization. I can't get out of sync.

[0005]

Embodiments will be described below with reference to the drawings. Figure 1
FIG. 1 is a configuration diagram of an embodiment of a fault point locating device according to the present invention. In the figure, 1A is a current test plug taken in from a current transformer having an A terminal, and the primary side can be short-circuited and disconnected from the secondary side during a test. 2A is a voltage test plug taken in from the transformer of the A terminal, and is designed so that the primary side can be opened and disconnected from the secondary side during the test. The current input through the test plug 1A is input through the input conversion circuits 3A1 and 3A2, and the voltage input through the test plug 2A is input through the input conversion circuits 4A1 and 4A2. It is input to the conversion circuit 5A (hereinafter referred to as DAU). The data converted into the digital amount is input to the arithmetic circuit 6A and executes a predetermined arithmetic operation. The calculation result of 6A and the data in the middle of the calculation are sent to the partner terminal via the communication interface 7A, and conversely the data of the partner terminal is received. The configuration of the B terminal is the same, and the subscript A may be replaced with B. However, in the arithmetic circuits 6A and 6B, the arithmetic contents are different between both terminals. In the present invention, the parent terminal which controls the synchronous control calculation and the orientation calculation processing will be described as the A terminal.
The B terminal acquires data, sends the data to the A terminal, and
It is configured to receive the synchronization control amount from the terminal and control so as to reach a predetermined sampling timing. The basic principle of this point is shown in Japanese Patent Laid-Open No. 3-282377, but since it is not directly related to the present invention, its details are omitted.

Since the figure shows an example of two terminals, the virtual branch point J of the power transmission line 8 will be described as an intermediate point. In general, in the case of two terminals, the purpose can be achieved by arbitrarily setting it at a predetermined position. Also, F indicates a failure point, X
Is the distance from the A terminal to the failure point. IA1, VA1
Is the current fetched from the A terminal synchronous control input circuit,
Voltage. IA2 and VA2 are current and voltage from the fault point locating input circuit. Subscript A is A terminal and B terminal is B
And Input conversion circuits 3A1, 3A2 (3B1, 3B
2) is a current transformer, 4A1, 4A2 (4B1, 4B2)
Converts the output from the transformer to an appropriate level, and outputs the output through a prefilter for removing high frequency components. This is a commonly used method, and no internal block diagram is given. The analog-digital conversion circuit 5A (5B) samples the input at regular intervals and applies the digital output to the operation output circuit 6A (6B).
The operation output circuit 6A (6B) later executes the operation shown in FIG. Here, here, the input conversion circuits 3A1, 3A2 (3B
The outputs of 1, 3B2), 4A1, 4A2 (4B1, 4B2) are the same as those of the analog-digital conversion circuit 5A (5B) unless otherwise confused.
1, IB2) and VA1, VA2 (VB1, VB2).

FIG. 2 is a block diagram for explaining the function of the arithmetic circuit 6A shown in FIG. The gist of the present invention is to separate input circuits for synchronous control and for orientation calculation. Therefore, although the calculation contents of the A terminal and the B terminal are different as described above, the gist of the present invention can be fulfilled if the function of the A terminal as the parent terminal is described. Since the basic synchronization control calculation and orientation calculation are known methods, they will be briefly described here. In FIG. 2, 201 is a means for detecting whether or not a failure has occurred in the system connected to the power transmission line 8. If no accident has occurred, the current IA1, VA1 and IB1, received from the B terminal via the communication interface 7A
The branch point voltage VJ from VB1 to the point J (intermediate point of the transmission line)
A and VJB are calculated by the branch point calculation means 202 based on the following formula. Z: The impedance of the transmission line between the terminals A and B, which is input as a set value or is preset as a constant.

The calculated voltage amounts VJA and VJB are AB
Obviously, if there is no failure between the terminals, they would be ideally equal. When this ideal state is established, the voltage amounts of both terminals are not equal because the sampling between both terminals is not the same time. The method of calculating the value of the difference will not be described in detail because it is not the gist of the present invention, but the outline is as follows. That is, the phase angle calculation means 203 obtains the phase angle by the following procedure, and the corresponding amount is sent from the sending means 204 to the B terminal via the communication interface 7A. (A). Send the sampling numbers assigned to each terminal to each other, and keep the sampling numbers until the phase angle θ obtained by the following equation (2) becomes the phase angle corresponding to the sampling cycle (2π / basic frequency of AC electricity / sampling frequency). Can match. (B). After (A), an amount equivalent to θ is sent to the B terminal, and the sampling time is controlled so that θ becomes zero at the B terminal. The failure detection unit 201 determines that there is a failure, and the intra-section failure determination unit 205 determines whether or not there is a failure in the transmission line section by using the current amounts IA1 and IB2 obtained from the orientation calculation input circuit. For example, the judgment is made based on the following formula (3). The following formula is simply based on the current differential method. IA2 + IB2 ≧ IK (setting value) …………………… (3)

When the equation (3) is satisfied, it is determined that there is an accident in the transmission line section, and the orientation value calculating means 206 calculates the orientation value X (distance from the A terminal) based on the following equation (4). . *: Conjugate complex number Im: Represents imaginary part Z: Impedance per unit length of transmission line Although the above formula describes the basic principle formula, in the case of short-circuit fault and one-line ground fault, the above-mentioned electric quantity Must be used properly. These various amounts are not always necessary for explaining the gist of the present invention, and are described in JP-B-58-2.
This is described in detail in Japanese Patent No. 9471. As explained above,
Once a failure is detected, the synchronous control is stopped, but the failure duration of the power system is at most 1-2 minutes in the low-order system (on the order of several seconds in the ultrahigh-voltage system), and the accuracy of the current crystal oscillator (10 ^-6 Therefore, only a deviation of about 60 to 120 μs occurs. Therefore, in the present invention, it is premised that there is no problem in practice even if the synchronous control is started by providing a certain protection time at the time of failure recovery. Figure 3 shows examples of current and voltage waveforms before and after a failure. The waveforms are shown when the dynamic range of the input conversion circuit does not greatly exceed and when it is small and exceeds the saturated range. As can be seen from the waveform, the current is seen to be small by that amount, which causes a localization error. Therefore, it is clear that this problem can be solved by using the electric quantities (IA2, IB2 and VA2, VB2) having a wide dynamic range after the failure detection, and this point is the essence of the present invention.

FIG. 4 is a block diagram of another embodiment of the present invention. In the figure, 1A1 and 1A2 are current test plugs respectively taken from the current transformer of the A terminal, and the primary side can be short-circuited and disconnected from the secondary side during the test. The former test plug is for synchronous control, and the latter is for fault location. Further, 2A1 and 2A2 are voltage test plugs respectively taken in from the transformer of the A terminal so that the primary side can be opened and the secondary side can be disconnected during the test. The current input via the test plugs 1A1 and 1A2 is input to the analog-digital conversion circuit 5A via the input conversion circuits 3A1 and 3A2, and the voltage input via the test plugs 2A1 and 2A2 is input to the analog-digital conversion circuit 5A via the input conversion circuits 4A1 and 4A2. Is entered. During the test, the test current sources 9A and 10A are switched by the test plugs 1A2 and 2A2 of the second means to input the desired current and voltage. The test quantity of electricity is applied by the second means, and immediately before the failure is generated and detected as shown in FIG. 2, the quantity of electricity (IA1, VA1, IB1, V
B1) is used, and after the detection, the electric quantity is not used, that is, the synchronous control is not performed. FIG. 5 shows the electric quantities (IA1, VA1) of the synchronization control input circuit before and after the application of the test electric quantity, the electric quantities (IA2, VA2) of the orientation input circuit, and the synchronization control signal. In the same figure, it is shown that a test electricity quantity for failure occurrence is applied to the test plugs 1A2, 2A2 (1B2, 2B2) at time t = to. As can be seen from the figure, the synchronization control signal is "1" to perform the synchronization control until the test electric quantity is applied.

[0011]

As described above, according to the present invention, the input circuit for the synchronous control and the input circuit for the fault point locating operation are configured separately, so that the following points can be solved. That is, by connecting the test plug for the input circuit for synchronous control to the current transformer and transformer of the transmission line, by connecting the test power source to the current test plug 1A2 and the voltage test 2A2 for fault location calculation, Until just before a failure occurs, the electric quantity of the power transmission line is input to the failure point locating device via the synchronization control input, and sampling synchronization can be performed. As a result, a stable fault location test can be carried out.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment of a fault point locating device according to the present invention.

FIG. 2 is a block diagram showing functions of the arithmetic circuit shown in FIG.

FIG. 3 is a current and voltage waveform diagram before and after a failure occurs.

FIG. 4 is a configuration diagram of another embodiment of the fault location device.

FIG. 5 is a diagram for explaining the effect of the present invention.

[Explanation of symbols]

 1A, 1A1, 1A2 Current amount test plug 2A, 2A1, 2A2 Voltage test plug 3A, 3A1, 3A2 Current input conversion circuit 4A, 4A1, 4A2 Voltage input conversion circuit 5A Analog-digital conversion circuit 6A Arithmetic circuit 7A Communication interface 8 power lines

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasuhiro Kurosawa No. 1 in Toshiba Fuchu factory, Fuchu, Tokyo (72) Inventor Shigenori Mizuguchi No. 1 in Toshiba Town, Fuchu, Tokyo Toshiba Fuchu factory, Ltd.

Claims (1)

[Claims] 1. The voltage and current of a plurality of terminals of a transmission line are collected, the voltage drop from each terminal to a branch point is calculated, and the obtained branch point voltage is equal if there is no failure in the section. A fault point locating device configured to automatically adjust the voltage and current collection timings of the terminals so that the branch point voltages are equalized by using the voltage and current for calculating a fault point. Means, second means for taking in voltage and current for controlling the timing of collecting the voltage and current, and second means for detecting a failure by the voltage and current taken in by the first means. And a third means for preventing the timing control by the means.