JPH0312566A - Fault section detecting method for transmission/ distribution lines - Google Patents

Abstract

PURPOSE:To easily and exactly decide a fault section by a miniature and inexpensive device by collecting and examining a phase difference of a load current or voltage before a fault and a fault current stored in each fault detector, when a fault is generated or at a suitable time. CONSTITUTION:An output of a current sensor 1 is shaped 3, inverted 4 and inputted to a waveform shifting circuit 5, and an output (e) delayed by a clock pulse 6 is brought to frequency division by an FF 7 and becomes a waveform (g) and an inverted waveform (h). Subsequently, a first and a second counters 11, 12 start or stop and store the count of the clock pulse by a rise and a fall of signals (i), (j) of the waveforms (g); (h). In this state, when an accident is generated in a transmission line and a detecting signal of the sensor 1 exceeds a reference value, an amplitude comparing circuit 13 detects it and outputs a signal (k), and from the FF 7, signals (l), (g) are outputted, and when they are in a high level H, count values of each counter 11, 12 are read out to a first and a second buffer. Also, a latching circuit 20 latches a buffer output, when a latch signal (m) inputted at the time of a fault from an FF 19 becomes H, and simultaneously, time from a timepiece 21 is outputted from a buffer 22.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a fault section detection method for a maintenance information system for power transmission and distribution lines.

[Conventional technology]

As a fault detection method for the maintenance information system of power transmission and distribution lines,
There is a constant phase comparison method.

The continuous phase comparison method constantly measures the phase difference between the zero-sequence current, overhead ground wire current, etc. of the relevant support and adjacent supports, and the phase changes when a ground fault or short circuit occurs. This system detects the occurrence of a fault and transmits the information to a monitoring station, and has been used in the past to detect faulty transmission lines between substations and to detect faulty sections based on overhead ground wire current between steel towers.

[Problem to be solved by the invention]

However, systems that use optical communication using a constant phase comparison method require constant optical output, which is not convenient for tower stations that rely on solar cells or the like for power.

There is a strong demand for power supplies for tower stations to be smaller and cheaper. Conventional failure section detectors are not suitable for systems because they are difficult to correct.

SUMMARY OF THE INVENTION Therefore, the present invention aims to downsize the power supply of a tower station, reduce costs, and increase the degree of freedom in system configuration.

[Means to solve the problem]

In order to achieve this objective, the method for detecting faulty sections of power transmission and distribution lines of the present invention includes fault detection devices installed on each support of the power transmission and distribution lines, and a monitoring device that collects information from these fault detection devices. In the fault section detection system for power transmission and distribution lines, the detection device compares the current or voltage waveform immediately before the fault with the waveform of the fault current, and stores the phase difference, and the monitoring device The information is collected from each failure detection device when a failure occurs or at an appropriate time, and based on the collected information regarding the phase difference, an interval in which the phase difference has changed is determined to be a failure interval.

[Effect]

In the present invention, current phase comparison is applied between towers.

The time from the positive rise of the load current (or voltage may be used) before the failure occurrence point to the positive rise of the fault current is counted and stored in an appropriate lock. The system's processing equipment compares the counts sent from each tower and determines the failure zone. By doing so, it becomes possible to detect simultaneous failures at multiple points under poor conditions of time and system constraints.

〔Example〕

Hereinafter, the present invention will be specifically explained based on Examples.

FIG. 1 is a circuit diagram showing the configuration of an embodiment of the present invention, and FIG. 2 is an operation waveform diagram of each part.

In FIG. 1, 1 is a current sensor installed on a power transmission line tower, etc., and 2 is a filter for noise removal. By installing the current sensor l at a position slightly shifted from the point equidistant from the three-phase power transmission line supported by the transmission line tower,
The sensor output is to be detected even during normal power transmission when a balanced current is flowing in the phase transmission line (Figure 2 (a)
(See first half).

The output of the current sensor 1 is waveform-shaped by a comparator 3, and the output, which becomes a rectangular wave as shown in Fig. 2, is inverted by an inverter 4 (see Fig. 2 (C)).
, the next waveform is manually input to the lift circuit 5.

- The clock generator 6 generates clock pulses as shown in FIG. 2(d), and the wave shift circuit 5
A signal delayed by two clock pulses from the human input waveform appears at the output of f, and a waveform obtained by dividing the frequency of (b) in half appears at the output of f.

The output of the waveform shift circuit 5 is the flip-flop circuit 7.
The waveform shown in FIG. 2 and its inverted waveform are output.
The first counter reset pulse signal shown in 1) is obtained.
The waveform (5) becomes the second counter reset pulse signal shown in FIG. 2(C) by the EOR gate 8 and AND gate 10. The first counter 11 starts counting the clock pulses of the clock pulse generator 6 at the falling edge of the pulse signal (1), and stops counting at the next rising edge.

The second counter 12 starts counting the clock pulses of the clock pulse generator 6 at the falling edge of the pulse signal (''), and stops counting at the next rising edge.

When an accident occurs on the power transmission line and the detection signal from the current sensor 1 exceeds the reference level shown in FIG. 2(a), the amplitude comparison circuit 13 in FIG. 1 detects this and the signal in FIG. It outputs an output signal that indicates. The AND gate 14 outputs the Q output (see FIG. 2 (f>)) of the flip-flop 7 only when a failure occurs, and outputs the first buffer 1 when the output (β) is H.
5, the count value of the first counter 11 is read out. AND
The gate 16 outputs the Q output (
(see FIG. 2(g)), and when the signal (g) is H, the count value of the second counter 12 is read out to the second buffer 17. A flip-flop 19 divides the frequency of the output waveform of the waveform shift circuit 5, and is reset by a signal inverted by the inverter 18 in the event of a failure.
A signal having a waveform shown in is outputted, and a latch signal is given to the latch circuit 20. The latch circuit 20 has a latch signal (E) of H
Latch the buffer output value at the time it becomes . In this example, the value of the second counter 12 is output from the buffer 17, so the count value of the second counter 12 is latched. This latch signal is synchronized with the rise of the input waveform after the failure, and the latched value indicates the count value from the rise before the failure to the rise after the failure.

Further, when a latch signal is generated, the buffer 22 outputs the time measured by the clock 21.

Figure 3 shows the flow of current in the case of two parallel transmission lines. t2 is the load current under normal conditions, and jl'+t
2 is the fault current. Also, S, , S, is a substation with power supply, and F is located across failure point X.

Consider the case where this device is installed on the steel tower of ~F4.

When the phase of the current I', t2 flowing through the steel towers F, , F is compared with the normal load current L1, I' is in phase and t2 is in opposite phase. So now, if we set the tarok of this device to be 15°/1 count, the count value of F,,F2 will be 24, and the count value of F,,F, will be 24+12(180
°).

Therefore, if we take the difference between the values collected by the monitoring device, F, -F2=O1F, -Fa=12, F, -F
, = O, and in the section between the failure points, the phase shift is 1
The value 2 (180°) appears, F2 and Fl.

The interval between the values of can be determined as the failure point.

Furthermore, since the failure detection device stores the data at the time of failure, there is no need for constant transmission of data, and data can be collected at any appropriate time in the monitoring device.

〔Effect of the invention〕

As described above, the present invention has the following advantages.

(2) Since the detection device stores the data, there is no need to constantly transmit it to the monitoring device, and the power supply for the detection device can be made smaller and cheaper.

■ Since the detection device stores data, data can be collected at will, increasing the flexibility of the system.

(2) Since the phase difference between the load current or voltage before the failure and the fault current is used as data, it is easy and accurate to determine the failure area.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a waveform diagram showing the operation of each part, and FIG. 3 is an explanatory diagram showing the flow of current in the case of two parallel power transmission lines. 1: Current sensor 3: Waveform adjuster 5: Waveform shift circuit 7; Flip-flop 9.10: AND gate 12; Second counter 14: AND gate 16: AND gate 18: Inverter 20: Latch circuit 22: Buffer filter inverter Clock generator EOR gate: 1st counter: amplitude comparison circuit; 1st buffer 2nd buffer flip-flop clock

Claims (1)

[Claims] 1. In a fault section detection system for power transmission and distribution lines that includes fault detection devices installed on each support of the power transmission and distribution lines and a monitoring device that collects information from these fault detection devices, each of the fault detection devices , compare the current or voltage waveform just before the failure with the fault current waveform, and memorize the phase difference.
The monitoring device is characterized in that information is collected from each fault detection device at the time of a fault occurrence or at an appropriate time, and based on the collected information regarding the phase difference, a section in which the phase difference has changed is determined to be a fault section. Method for detecting faulty sections of power transmission and distribution lines.