JP3368962B2 - Surge identification device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surge discriminating device for discriminating the type of surge generated in a power transmission line, and more particularly to a surge discriminating device for discriminating a precursor surge contained in a lightning surge or an induced lightning surge. It is a thing.

[0002]

2. Description of the Related Art It is known that a surge occurs in a transmission line due to a short circuit, a ground fault, or a thunder. These surges have various characteristics such as a wave crest length and a peak value depending on the cause of occurrence. Particularly, the lightning surge and the induced lightning surge are characterized in that a precursor surge appears. Here, the precursor surge means a minute change in voltage before the main surge pulse is generated, and is generated on the transmission line by the precursor current flowing prior to the return stroke current of the lightning.

[0003]

In the conventional surge receiving type orientation system, when a lightning surge is received,
Stop the surge reception counter by creating a surge with the precursor surge removed as much as possible. The slave station sends a synchronization signal via the ground communication line to the master station at the stop timing, and the master station determines the surge occurrence location from the difference between the counter values of the master and slave station reception counters. Is configured. On the other hand, Japanese Patent Application No. 5 filed by the applicant
No. -261230 discloses a device for determining the type of surge by extracting various characteristic portions of the received surge as surge waveform characteristic information and comparing it with reference information. In this device, the presence or absence of the precursor phenomenon is also determined by comparing the information of a predetermined portion of the surge digitized through the A / D converter with the reference information stored in the memory. However, this device has a problem that the precursor surge cannot always be detected reliably and accurately. Therefore, it is an object of the present invention to provide a surge identification device capable of reliably and accurately detecting a precursor surge included in a lightning surge or an induced lightning surge.

[0004]

The object of the present invention is to:
Surge receiving means for receiving a surge generated in the power transmission line,
Extracting a signal component from which the direct current rise is almost removed from the surge, based on this signal component, pulse generating means for generating a pulse, and counting means for counting the number of pulses output by the pulse generating means, Level detecting means for detecting a predetermined level of the surge, and judging means for judging that a precursor surge has occurred based on the number of pulses counted by the counting means until the predetermined level is detected. It is achieved by a surge identification device characterized in that it is provided. In a preferred embodiment of the present invention, the pulse generating means provides an offset means for giving a predetermined offset to the output signal of the surge receiving means, a peak hold means for holding a peak value of the output signal of the offset means, and It has an amplifying means for amplifying an output signal of the surge receiving means, a comparing means for comparing the output signal of the peak holding means and an output signal of the amplifying means, and generates a pulse based on the signal given by the comparing means. It is configured to generate. In a further preferred aspect of the present invention, the pulse generating means includes a filter means for passing a signal component of a predetermined frequency or less from an output signal of the surge receiving means, and the output signal of the surge receiving means and the filter means are provided. Based on the output signal component, extract the signal component from which the DC rise component is almost removed from the surge and extract a minute vibration or vertical movement.
It is configured to generate a pulse by the.

In another embodiment of the present invention, a surge identification device is a surge receiving means for receiving a surge generated in a transmission line, and a signal extraction for extracting a signal component obtained by substantially removing the DC rise from the surge. Means, measuring means for measuring the time during which the signal component from the comparison signal generating means is in a state of being larger than a reference level, level detecting means for detecting a predetermined level of the surge, and detecting the predetermined level. And a determining unit that determines that a precursor surge has occurred based on the time measured by the measuring unit. In a further preferred aspect of the present invention, further, pulse generating means for generating a pulse due to minute vibration or vertical movement based on the signal component extracted by the signal extracting means, and the pulse generating means. And counting means for counting the number of pulses output by
If the number of pulses counted by the counting unit before the determination unit detects the predetermined level is smaller than a predetermined number, a precursor surge has occurred based on the time measured by the measurement unit. Is configured to determine.

[0006]

According to the present invention, a signal component obtained by removing the DC rise component from the surge is extracted, and the pulse number of the pulse based on this signal component, that is, the minute vibration or the vertical vibration frequency included in the surge. Alternatively, it is possible to accurately determine the precursor surge with a simple configuration because it is determined from the vertical movement number that the precursor surge has occurred. According to a preferred embodiment of the present invention, the counting means is provided with the signal obtained by comparing the signal obtained by adding the offset to the output signal of the surge receiving means and the signal obtained by amplifying the output signal by the signal extracting means. The counting means can reliably count the minute vibration frequency or the vertical movement number of the surge in the precursor state, and can accurately determine whether the precursor surge has occurred. According to a further preferred aspect of the present invention, the counting means is provided with a signal indicating a difference value between the signal obtained by adding the offset to the output signal of the surge receiving means by the signal extracting means and the signal obtained by amplifying the output signal. Since it is provided, the counting means can reliably count the minute vibration frequency or the vertical movement number of the surge in the precursor state, and can accurately determine that the precursor surge has occurred.

According to a further preferred embodiment of the present invention, the counting means is provided with a signal substantially corresponding to the DC rise of the surge obtained by the filter means and a signal based on the output signal of the surge receiving means. The counting means can surely count the minute vibration frequency or vertical movement frequency of the surge in the precursor state, and can accurately determine that the precursor surge has occurred. According to another embodiment of the present invention, when the measuring unit measures a relatively large fluctuation of the surge waveform, the determining unit determines that the precursor surge has occurred, so that minute vibration or vertical movement does not occur repeatedly. It is possible to accurately determine such a precursor surge. According to a further preferred aspect of the present invention, the determining means compares the time measured by the measuring means with the predetermined time when the number of pulses counted by the second counting means is smaller than the predetermined number. Therefore, even if a small amount of vibration or vertical movement does not occur repeatedly and a precursor surge occurs that causes only a relatively large fluctuation, it is possible to accurately determine this. Become.

[0008]

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is a block diagram showing the configuration of a surge identification device according to an embodiment of the present invention. This surge identification device includes a first determination unit 10 and a second determination unit 30. First discriminator 10
Compares the output voltage of the surge receiving unit 12 that receives a surge from a power transmission line (not shown) and the surge receiving unit 12 with a threshold value VTH larger than the noise level, and when the output voltage is larger, The output voltage of the first level detection unit 14 that outputs the first counter start signal and the surge reception unit 12 are compared with a predetermined voltage V1, and when the output voltage is higher, the first counter Second level detecting means 16 for outputting a stop signal and a second counter start signal, a first counter for starting the counting by the first counter start signal and stopping the counting by the first counter stop signal 18, comparing the output voltage of the surge receiver 12 with a predetermined voltage V2, and outputting a second counter stop signal when the output voltage is higher. Level detector 20, a second counter 22 that starts counting by the second counter start signal and stops counting by the second counter stop signal, and a first counter that holds the data of the first counter. The data latch 24, the second data latch 26 that holds the data of the second counter, and the data from the first and second data latches 24 and 26 are received, and the first counter start signal is the trigger signal. CPU2 which accepts as the above and outputs a reset signal to the first and second counters 18 and 22 in a predetermined case.
It is composed of 8. The first, second and third level detectors 14, 16 and 20 each have a CPU.
A VTH setting signal, a V1 setting signal and a V2 setting signal are applied from 28, and the voltage levels of VTH, V1 and V2 can be changed by these signals.

Further, the second discriminating section 30 provides a level offset circuit 32 which gives a predetermined offset to the output signal of the surge receiving section 12, and a peak hold circuit 34 which holds the peak value of the output of the level offset circuit 32. An amplifier 36 for amplifying the output signal of the surge receiver 12, a level comparator 38 for comparing the output of the peak hold circuit 34 with the output of the amplifier 36, and outputting a signal when the output of the amplifier 36 is larger, Comparator 38
4 that counts by using the output of
0 and the data of the counter 40 are held, and the data latch 42 for giving this data to the CPU 28 at a predetermined timing, the output of the level comparator 38 as a counter start signal, and a clock for the counter 44 and the counter 44 for starting counting. It is composed of a clock generator 46 to be supplied and a data latch 48 which holds the data of the counter 44 and supplies this data to the CPU 28 at a predetermined timing. The characteristics of the precursor surge included in the lightning surge and the induced lightning surge will be described below. Lightning surges and induced lightning surges are caused by a precursor current that flows before the main lightning strike, causing the voltage on the transmission line to slightly increase over time (hereinafter referred to as the "precursor state") and a precursor of several tens of microseconds. After the state, it is possible to classify it into a state in which the voltage thereof rapidly changes due to return stroke current or the like (hereinafter, referred to as "lightning stroke state"). FIG. 2 is a diagram schematically showing the waveforms of the lightning surge and the induced lightning surge that occur in the power transmission line, and the surge from the point indicated by arrow A to the point indicated by arrow B has been described above. The surge from the point indicated by arrow B to the point indicated by arrow C is almost equivalent to the precursor state.
It is almost equivalent to the above-mentioned lightning stroke state. As is apparent from FIG. 2, the differential coefficient differs between the direct current rise of the voltage in the precursor state and the lightning stroke state. Therefore,
In the first discriminating unit 10, the above-mentioned threshold value VTH is set to be slightly higher than the noise level on the transmission line,
The second voltage V1 is set to the node between the precursor state and the lightning strike state, that is, the differential coefficient of the direct current rise of the voltage in the precursor state,
It is preferable to set so as to substantially correspond to the point where the differential coefficient of the voltage in the lightning stroke state changes. This point can be set based on experimental data and the like. further,
In this embodiment, the second voltage V2 is the second voltage V2.
Almost twice as much as 1 , more precisely V2 = (V1-VTH) × 2
Is set to. Therefore, the time from when the output signal from the surge receiver 12 becomes larger than the threshold value VTH to V1 is t1, and when the output signal becomes larger than the first voltage V1 and then the second voltage V2. If the time required to reach t2 is t2, and the waveform of the surge is substantially linear, the time t1 and the time t2 become substantially equal, and the voltage V1 is reached after the output signal becomes larger than the voltage VTH. The differential coefficient of the surge from the second voltage V1 to the third
When it is smaller than the differential coefficient of the surge until reaching the voltage V2 , the time t1 becomes longer than the time t2.

The operation of the first discriminating section 10 of the surge identifying apparatus constructed as described above will be described below. Output signals from the surge receiver 12 are given to the first, second and third level detectors 14, 16 and 20, respectively. The output signal of the first level detector 14 is the threshold value VTH.
When it becomes larger than the above, the first counter start signal is output to the first counter 18. In the case of the surge wave shown in FIG. 2, the first counter 18 starts counting at the time indicated by arrow A based on the clock signal output from the clock generator (not shown). Next, the second level detection unit 16 outputs the first counter stop signal and the second counter start signal to the first counter 18 and the first counter 18 when the output signal becomes larger than the first voltage V1. It outputs to each of the two counters 22. In the case of the surge wave shown in FIG. 2, at the time point indicated by the arrow B, the first counter 18 finishes its counting,
At the same time, the second counter 22 starts counting based on the clock signal output from the clock generator (not shown). Further, when the output voltage becomes higher than the second voltage V2, the third level detection unit 20
The second counter stop signal is output to the second counter 22. In the case of the surge wave shown in FIG. 2, arrow C
The second counter 22 finishes its counting at the time point indicated by. At the time when the first and second counters 18 and 22 finish counting, the first counter 18 shows the counter value corresponding to the time indicated by t1 in FIG. 2, and the second counter 22 shows the counter value shown in FIG. Shows the counter value corresponding to the time indicated by t2. The counter values of the first and second counters 18 and 22 are given to the data latches 24 and 26, respectively, and the data latches 24 and 26 respectively hold the counter values by the latch control signal from the CPU 28. The CPU 28 reads the counter value held in the data latches 24 and 26 at a desired timing. Then, the CPU 28 compares these count values, and when the count value of the first counter 18 is larger than the count value of the second counter 20, the received surge includes the precursor surge, that is, The received surge is
The lightning surge or the induced lightning surge is determined, and the precursor surge identification signal is output to an external processing device (not shown) or the like. An external processing device (not shown) performs more detailed identification of the received surge based on the precursor surge identification signal.

The CPU 28 receives the first counter start signal from the first level detector 14 as a trigger signal, starts counting in response to the reception of the trigger signal, and starts a predetermined time t3. When there is no output from the second level detection unit 16 by the end of counting the count value corresponding to, the time-up determination that outputs a reset signal that resets the first and second counters 18 and 22 A section 50 is provided. Therefore, when the output signal of the surge receiving unit 12 temporarily becomes larger than the threshold value VTH, the time-up determining unit 50 determines that the first counter 1 is ready.
With 8, the counting is started. For example, as shown in FIG. 3, although the output signal of the surge receiving unit 12 temporarily exceeds the threshold value VTH due to noise or the like, thereafter, counting of the count value corresponding to the predetermined time t3 is finished. If the second voltage V1 is not reached by the time
At the time point indicated by the arrow D in FIG. 3, the contents of the first and second counters 18 and 22 are reset. By providing the time-up determination unit 50, malfunction of the surge identification device due to noise or the like can be prevented. According to the first discriminating unit according to the present embodiment, the time from when the output signal of the surge receiving unit reaches the threshold value VTH to when it reaches the second level V1 and when it reaches the second level V1. From the third
It is possible to accurately determine the presence or absence of the precursor surge based on the comparison with the time required to reach the level V2 .

Next, regarding the operation of the second discriminating section 30,
This will be described below. Here, the characteristics of the precursor surge included in the lightning surge and the induced lightning surge will be described again.
As shown in Fig. 2, in the case of lightning surges and induced lightning surges, the maximum level is several μs during the precursory state.
There is a slight vibration or vertical movement for each c. Therefore,
The second discriminating unit 30 discriminates the precursor surge by obtaining from the output signal of the surge receiving unit 12 a signal that slightly oscillates or vertically moves by removing the DC rise component. As shown in FIG. 1, the level offset circuit 32 adds a predetermined offset to the output signal of the surge receiver 12 to reduce malfunction due to noise. In the present embodiment, the level offset circuit 32 gives an offset voltage of Voff to the output voltage. For example, when the surge indicated by the solid line in FIG. 4 is received by the surge receiver 12, the output of the level offset circuit 32 becomes that indicated by the dotted line in FIG. Further, the output of the level offset circuit 32 is given to the peak hold circuit 34, and the maximum value is held. The output of the peak hold circuit 34 is shown by the solid line in FIG. The output signal of the surge receiving unit 12 is also given to the amplifier 36, and an amplified signal amplified to a predetermined magnification is obtained as shown by the solid line in FIG. In order to facilitate the comparison, the amplification factor of this amplifier 36 is set to 3/2 in this embodiment. Next, in the level comparator 38, the peak hold circuit 34
Is compared with the output of the amplifier 36. Figure 4
When a surge as indicated by the solid line is applied to the surge receiver 12, the range of time corresponding to the shaded area in FIG. 7, that is, the time between t4 and t5, t6
A pulse is generated that causes the signal to go high between t and t7 and between times t8 and t9.

The counter 40 has a level comparator 38.
The pulse output from the clock is used as a clock to perform counting, and further, the second level detection unit 1 of the first determination unit 10
The counting is terminated based on the signal from 6. Therefore, when the surge receiving unit 12 outputs the signal shown by the solid line in FIG. 4, the counter 40 counts 3 and ends the counting, as shown in FIG.
The counter value of the counter 40 is given to the data latch 42, and the data latch 42 holds the counter value by the latch control signal (not shown) from the CPU 28. The CPU 28 reads the counter value held in the data latch 42 at a desired timing. Also, the counter 44 responds to the rising edge of the pulse from the level comparator 38, performs counting based on the clock from the clock generator 46, and further responds to the trailing edge of the pulse from the level comparator 38. Finish counting. Therefore, the count value of the counter 44 indicates the time when the pulse from the level comparator 38 as shown in FIG. 7 has the logical value "1". The counter value of the counter 44 is given to the data latch 48, and the data latch 48 holds the counter value by the latch control signal (not shown) from the CPU 28. The CPU 28 reads the counter value held in the data latch 48 at a desired timing.

Next, when the count value of the counter 40 is larger than the predetermined reference value, the CPU 28 determines that the received surge includes the precursor surge, and outputs the precursor surge identification signal to the external processing device. (Not shown) or the like. In other words, the second discriminating unit 30 makes a precursor to the received surge when the number of vibrations of the signal obtained by substantially removing the DC rise component from the output signal of the surge receiving unit 12 is larger than a predetermined reference value. It is determined that the surge is included, that is, the received surge is a lightning surge or an induced lightning surge. In the present embodiment, since the above-mentioned reference value is set to 1, when the number of vibrations of the signal obtained by substantially removing the DC rise component from the output signal of the surge receiving unit 12 is plural times, , It is determined that the received surge includes precursor surge. On the other hand, when the count value of the counter 40 is less than or equal to the predetermined reference value, the counter value of the counter 44 held in the data latch 48 is read, and this counter value is
When it is larger than the predetermined reference value, it is determined that the received surge includes the precursor surge, and the precursor surge identification signal is output to an external processing device (not shown) or the like. In other words, even if the number of vibrations of the signal obtained by substantially removing the DC rise component from the output signal of the surge receiver 12 is less than or equal to a predetermined reference value, the voltage in the vibration is relatively high, When the surge is held for a predetermined time or more, it is determined that the received surge includes the precursor surge, that is, the received surge is the lightning surge or the induced lightning surge.

In an external processing device (not shown),
Based on this precursor surge identification signal, the received surge is identified in more detail. Second according to the present embodiment
According to the discriminating unit 30 of FIG. 3, the presence or absence of the precursor surge is accurately determined based on the number of times of vibration of the signal obtained by substantially removing the DC rise from the output signal of the surge receiving unit 12 or the time when the signal is at a high level. Can be determined. Next, another embodiment of the present invention will be described. Figure 8
It is a block diagram which shows the structure of the surge identification device concerning the other Example of this invention. In this embodiment, the surge receiver 1
2 output signals are received, and among these signals, the filter unit 5
2 is provided and the output signal of the filter unit 52 is provided to the first, second and third level detecting units. The filter section 52 separates a signal larger than the first level and a signal smaller than the first level from the window comparator 52a, a low-pass filter 52b that passes only a signal component having a predetermined frequency or less, and outputs of the window comparator 52a and the low-pass filter 52b. Is composed of a summing amplifier 52c for summing. Further, the low-pass filter 52b has a cutoff frequency sufficient to remove minute vibrations in the precursor state from the output signal of the surge receiver 12. Other configurations are the same as those of the above-described embodiment.

The operation of the first discriminating section 10 of the surge identifying apparatus constructed as described above will be described below. The output signal from the surge receiving unit 12 is given to the filter unit 52, and the filter unit 52 outputs the voltage of the output signal.
For signals smaller than V1, only signal components of a predetermined frequency or lower are output, and for signals larger than voltage V1 , the signals are output as they are. For example, the surge receiver 12
From when the signal shown in FIG. 2 is output, full
A signal as shown in FIG. 9 is output from the filter section 52b , and the first, second and third level detecting sections 14, 1 are output.
Given to 6,20. The first level detection unit 14 outputs the first counter start signal to the first counter 18 when the output signal becomes larger than the threshold value VTH. Then, the second level detector 16 outputs the output signal
When the voltage becomes higher than the first voltage V1, the first counter stop signal and the second counter start signal are output to the first counter 18 and the second counter 22, respectively. Furthermore, the third level detection unit 20
When the output voltage becomes higher than the second voltage V2, the second counter stop signal is sent to the second counter 2
Output to 2. When the first and second counters 18 and 22 finish counting, the first and second counters 1
The counter values of 8 and 22 are respectively the data latch 2
Data latches 24 and 26 are provided to CP
Each of the counter values is held by the latch control signal from U28. The CPU 28 reads the counter value held in the data latches 24 and 26 at a desired timing. Next, the CPU 28 compares these count values, and when the count value of the first counter 18 is larger than the count value of the second counter 20, the received surge includes the precursor surge, that is, It is determined that the received surge is a lightning surge or an induced lightning surge, and a precursor surge identification signal is output to an external processing device (not shown) or the like.

Further, the CPU 28 receives the first counter start signal from the first level detector 14 as a trigger signal, starts counting in response to the reception of the trigger signal, and at a predetermined time t3. A time-up determination unit that outputs a reset signal that resets the first and second counters 18 and 22 when there is no output from the second level detection unit 16 by the end of counting the corresponding count value. The provision of 50 is also the same as in the above-described embodiment. Further, the second discriminating unit 30 is exactly the same as that of the above-mentioned embodiment, and therefore its explanation is omitted. According to the first discriminating unit according to this embodiment, the output signal of the surge receiving unit 12 is received, and the filter unit 52 which passes only the signal component of the predetermined frequency or less is provided, and the surge in the precursor state is provided. Since the signal from which the minute vibration of is removed is given to the first, second and third level detecting units 14, 16 and 20, it is possible to more accurately determine the presence or absence of the precursor surge. Next, a surge identification device according to still another embodiment of the present invention will be described. Figure 1
FIG. 0 is a block diagram showing the configuration of the surge identification device according to this embodiment. As shown in FIG. 10, this surge identification device includes a first determination unit 10 and a second determination unit 6.
It consists of zero. Since the first discriminating unit 10 is the same as that of the first embodiment, the description thereof will be omitted. Second determination unit 60 accepts the output signal of the surge receiving section 12, and the larger signal than VTH, the window comparator 62 to separate the it from the small signal, inverts the small signal from the separated VTH by the window comparator 62 Inverting amplifier 64, window comparator 6
Of the signals from 2, the low-pass filter 66 and the inverting amplifier 64 that pass only the signal components smaller than a predetermined frequency
Output signal of the low-pass filter 66 and an addition amplifier 68 for adding the output signal of the low-pass filter 66, an inverting amplifier 70 for inverting the output signal of the addition amplifier 68, a Schmitt circuit 72 for receiving the output signal of the inverting amplifier 70 and generating a pulse from this signal, A counter 74 that counts with the pulse from the Schmitt circuit 72 as a clock, holds the data of the counter 74, and counts with the output of the data latch 76 that gives this data to the CPU 28 at a predetermined timing and the Schmitt circuit 72 as a counter start signal. Data of the counter 78 for starting the clock, the clock generator 80 for supplying the clock to the counter 78, and the counter 78, and at the same time, CP
It is composed of a data latch 82 applied to U28.

The operation of the second discriminating section 60 according to this embodiment will be described below. As shown in FIG. 10, the output signal from the surge receiver 12 is given to the window comparator 62. The window comparator 62 has a voltage V detected by the first level detector.
A signal smaller than TH and a signal smaller than TH are separated, and a signal smaller than voltage V1 is output to inverting amplifier 64 and low-pass filter 66. Therefore, the output from the window comparator 62 is a portion smaller than the voltage V1 in the output signal of the surge receiving unit 12, as shown by the curve 90 represented by the broken line in FIG. The output signal from the window comparator 62 is provided to the inverting amplifier 64. Since the amplification factor of the inverting amplifier 64 is set to 1, the output from the inverting amplifier 64 is a signal obtained by inverting the sign of the output signal of the window comparator 62, as shown by the curve 92 in FIG. In addition, the window comparator 62
The output signal from is also applied to the low pass filter 66. The low-pass filter 66 has a cutoff frequency sufficient to remove minute vibrations in the precursor state from the output signal of the surge receiver 12. Therefore, the output of the low-pass filter 66 becomes a signal corresponding to approximately the amount of DC rise of the output of the window comparator 62, as shown by the curve 94 in FIG. The output signal of the inverting amplifier 64 and the output signal of the low-pass filter 66 are given to the summing amplifier 68, and the signal as shown by the curve 96 in FIG. 11 is output. The output signal of the summing amplifier 68 is
Further, it is inverted by the inverting amplifier 70. Therefore, from the inverting amplifier 70, it is possible to obtain a signal in which the DC rise component is substantially removed from the output signal of the surge receiver 12.

The output signal of the inverting amplifier 70 is applied to the Schmitt circuit 72, and the Schmitt circuit 72 outputs a pulse based on this output signal. Counter 74
Performs counting with the pulse output from the Schmitt circuit 72 as a clock, and further ends counting based on the output signal from the second level detection unit 16 of the first determination unit 10. The counter value of the counter 72 is given to the data latch 76, and the data latch 76 holds the counter value by the latch control signal (not shown) from the CPU 28. The CPU 28 reads the counter value held in the data latch 76 at a desired timing. Further, the counter 78 responds to the rising edge of the pulse from the Schmitt circuit 72, performs counting based on the clock from the clock generator 80, and further responds to the falling edge of the pulse from the Schmitt circuit 72. Finish counting. Therefore, the count value of the counter 78 is the logical value of the pulse from the Schmitt circuit 72.
The counter value of the counter 78 is given to the data latch 82, and the data latch 82 holds the counter value by the latch control signal (not shown) from the CPU 28.
Reads the counter value held in the data latch 82 at a desired timing.

Next, when the count value of the counter 74 is larger than the predetermined reference value, the CPU 28 determines that the received surge includes a precursor surge, and processes the precursor surge identification signal by external processing. Output to a device (not shown) or the like. In other words, the second discriminating unit 60, when the number of vibrations of the signal obtained by substantially removing the direct-current rise component from the output signal of the surge receiving unit 12 is larger than the predetermined reference value, is added to the received surge. It is determined that the surge is included, that is, the received surge is a lightning surge or an induced lightning surge. In the present embodiment, since the above-mentioned reference value is set to 1, when the number of vibrations of the signal obtained by substantially removing the DC rise component from the output signal of the surge receiving unit 12 is plural times, , It is determined that the received surge includes precursor surge. On the other hand, when the count value of the counter 74 is less than or equal to the predetermined reference value, the counter value of the counter 78 held in the data latch 82 is read, and this counter value is
When it is larger than the predetermined reference value, it is determined that the received surge includes the precursor surge, and the precursor surge identification signal is output to an external processing device (not shown) or the like. In other words, even if the number of vibrations of the signal obtained by substantially removing the DC rise component from the output signal of the surge receiver 12 is less than or equal to a predetermined reference value, the voltage in the vibration is relatively high, If it is held for more than a predetermined time, if the received surge contains a precursor surge,
That is, it is determined that the received surge is a lightning surge or an induced lightning surge.

In an external processing device (not shown),
Based on this precursor surge identification signal, the received surge is identified in more detail. Second according to the present embodiment
According to the discriminating unit 60, the presence or absence of the precursor surge is accurately determined based on the number of times of vibration of the signal obtained by substantially removing the DC rise from the output signal of the surge receiving unit 12 or the time at which the vibration is at a high level. Can be determined. The present invention is not limited to the above embodiments, and various modifications can be made within the scope of the invention described in the claims, and those modifications are also included in the scope of the present invention. Needless to say. For example, in the above embodiment, these voltages are set so that the ratio between the first voltage V1 and the second voltage V2 is approximately 1: 2, but the present invention is not limited to this. Rather, it is possible to set these voltages in virtually any ratio. For example, the ratio between the first voltage V1 and the second voltage V2 is 1:
It is also possible to set it as n (n is a number larger than 1). In such a case, the time t1 from the threshold VTH to the first voltage and the time t2 from the first voltage to the second voltage are compared with t1 and t2 / (n-1). Then
When t1 is larger, it is determined that the received surge includes the precursor surge.

Further, in the embodiment shown in FIG. 8, the filter section 52 comprises a window comparator 52a, a low pass filter 52b and a summing amplifier 52c, but a notch filter may be used instead of the low pass filter. That is clear. In addition, the filter unit 5
It is also possible for 2 to simply consist of a low-pass filter. Further, in the above-described embodiment, the CPU 40 determines, based on the information provided from the second discriminating unit, that the number of vibrations of the signal obtained by substantially removing the DC rise component of the output signal of the surge receiving unit 12 is a predetermined reference value. Greater than or
Even if the number of vibrations is less than or equal to the predetermined reference value,
When the voltage in the vibration is kept relatively high for a predetermined time or longer, it is determined that the received surge includes the precursor surge, and the precursor surge identification signal is generated. However, the algorithm for generating the precursor surge identification signal in the CPU 40 is not limited to this, and for example, the state in which the voltage of the vibration is relatively high is maintained for a predetermined time or longer without depending on the number of times of vibration of the signal. If so, it may be configured to generate a precursor surge identification signal.

Further, each means described in the claims does not necessarily mean a physical means, and even when the function of each means is realized by software,
The present invention includes. For example, the function of one means is 2
It may be realized by the above physical means, or the functions of two or more means may be realized by one physical means.

[0024]

According to the present invention, it is possible to provide a surge identifying device capable of reliably and accurately detecting a precursor surge caused by a precursor phenomenon.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a surge identification device according to an embodiment of the present invention.

FIG. 2 is a diagram schematically showing waveforms of a lightning surge and an induced lightning surge occurring in a power transmission line.

FIG. 3 is a diagram for explaining an operation of a time-up determination unit.

FIG. 4 is a diagram showing an input signal and an output signal of the level offset circuit of the second discriminating unit according to the embodiment of the present invention.

FIG. 5 is a diagram showing an input signal and an output signal of the peak hold circuit of the second discriminating unit according to the embodiment of the present invention.

FIG. 6 is a diagram showing an input signal and an output signal of the amplifier of the second discriminating unit according to the embodiment of the present invention.

FIG. 7 is a diagram showing an input signal and an output signal of the level comparator of the second discriminating unit according to the embodiment of the present invention.

FIG. 8 is a block diagram showing a configuration of a surge identification device according to another embodiment of the present invention.

FIG. 9 is a diagram showing an output signal of the filter unit of the first discriminating unit according to another embodiment of the present invention.

FIG. 10 is a block diagram showing a configuration of a surge identification device according to still another embodiment of the present invention.

FIG. 11 is a diagram showing respective output signals of an inverting amplifier, a low-pass filter, and a summing amplifier of a second discriminating unit according to still another embodiment of the present invention.

[Explanation of symbols]

10 First discriminator 12 Surge receiver 14 First level detector 16 Second level detector 18 first counter 20 Third level detector 22 Second counter 24 First data latch 26 Second data latch 28 CPU 30 Second discriminator 32 level offset circuit 34 Peak hold circuit 36 amplifier 38 level comparator 40,44 counter 42,48 data latch 46 clock generator

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A 52-66307 (JP, A) JP-A 52-66308 (JP, A) JP-A 50-119948 (JP, A) JP-A 52- 109814 (JP, A) Actual development 56-105862 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) G01R 31/00 G01R 29/00 G01R 31/08 G01R 31/02 H02H 3/08

Claims (5)

(57) [Claims] 1. A surge receiving means for receiving a surge generated in a power transmission line, and a signal component in which a DC rise component is substantially removed from the surge received by the surge receiving means to extract a minute vibration or vibration.
Or pulse generation means for generating a pulse based on a signal component due to vertical movement, counting means for counting the number of pulses output by the pulse generation means, level detection means for detecting a predetermined level of the surge, A surge identifying device comprising: a determining unit that determines whether a precursor surge has occurred, based on the number of pulses counted by the counting unit until the predetermined level is detected. 2. The pulse generating means includes an offset means for giving a predetermined offset to the output signal of the surge receiving means, a peak hold means for holding a peak value of the output signal of the offset means, and a surge receiving means of the surge receiving means. It has an amplifying means for amplifying the output signal, and a comparing means for comparing the output signal of the peak holding means with the output signal of the amplifying means, and the pulse is generated based on the signal given by the comparing means. The surge identification device according to claim 1, wherein the surge identification device is configured. 3. The pulse generation means comprises a filter means for passing a signal component of a predetermined frequency or less from the output signal of the surge receiving means, and the output signal of the surge receiving means and the signal component output from the filter means. 2. The surge discrimination according to claim 1, wherein the surge is configured to extract a signal component from which the DC rise component is substantially removed, and to generate a pulse based on the signal component. apparatus. 4. A surge receiving means for receiving a surge generated in a power transmission line, a signal extracting means for extracting a signal component from which a DC rise component is substantially removed from the surge, and a signal component from the signal extracting means, Based on the time measured by the measuring means until the predetermined level is detected, the measuring means for measuring the time in the state larger than the reference level, the level detecting means for detecting the predetermined level of the surge, And a discrimination means for discriminating that a precursor surge has occurred. 5. A pulse generating means for generating a pulse based on a signal component due to a minute vibration or a vertical movement extracted by the signal extracting means, and a counting for counting the number of pulses generated by the pulse generating means. The number of pulses counted by the counting means until the predetermined level is detected is smaller than a predetermined number, the precursor is based on the time measured by the measuring means. The surge identification device according to claim 4, wherein the surge identification device is configured to determine that a surge has occurred.