JP2012104598A - Spd with deterioration alarm function - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve reliability by correctly grasping the deterioration of a protection element.SOLUTION: An SPD with a deterioration alarm function comprises: varistors 8 to 11 connected between power supply terminals 1 to 3 and a ground terminal 4; a gas arrestor 12 connected between the varistors 8 to 11 and the ground terminal 4, and having a discharge gap; and a photo transistor 17 disposed close to the gas arrestor 12, and detecting light emission at the time of the discharge of the gas arrestor 12 due to a surge current. The SPD also comprises a CPU 18 for determining whether output from the photo transistor 17 exceeds a threshold value set on the basis of the light-emitting time of the gas arrestor 12 or not, and an alarm lamp 20 for displaying a deterioration alarm on the basis of the output of the CPU 18.

Description

  The present invention is used in a communication line such as a power circuit in a distribution board and a telephone line, and absorbs a surge voltage caused by a direct lightning strike or an induced lightning to protect a device from the direct lightning strike or induced lightning. Surge Protective Device).

  For example, to prevent lightning damage from direct lightning or induced lightning, the surge current is shunted by limiting transient overvoltages caused by direct lightning or induced lightning between electrical equipment and the earth in single-phase or three-phase AC circuits. SPD is installed as a device to perform. Some SPDs include protective elements such as varistors and gas arresters.

  In this type of SPD, protective elements such as varistors and gas arresters gradually deteriorate due to repeated application of surge voltage, and protective functions such as varistor operation start voltage and gas arrester discharge start voltage become out of specification. Decreases over time.

  Therefore, in order to detect the deterioration of the protective element at an early stage and replace it, conventionally, the number of operation of the protective element due to the application of surge voltage is counted, and the deterioration state of the protective element is determined based on the counted number of operations. An SPD with a counter function to be grasped has been proposed (for example, see Patent Document 1).

  This Patent Document 1 is for counting the number of discharges of a discharge element such as a gas arrester, a sensor for detecting light emission during discharge of the discharge element, a counter for counting the number of light emission detected by the sensor, A counter operating battery is used, and a phototransistor is used as the aforementioned sensor.

Japanese Patent Laid-Open No. 10-27670

  By the way, in the SPD with a counter function disclosed in the above-mentioned Patent Document 1, light emission at the time of discharge of the discharge element is detected by a phototransistor, and the detected number of times of light emission is displayed on the counter, so that the deterioration state of the discharge element Trying to figure out.

  However, it is difficult to grasp the deterioration state of the discharge element only by the number of times of light emission of the discharge element. In other words, surge currents that flow in due to lightning strikes can vary in size, and if a small surge current repeatedly flows in, the discharge element will deteriorate so much even if the discharge element emits more times. On the contrary, when a large surge current repeatedly flows, the discharge element is considerably deteriorated even if the discharge element emits a small number of times. Thus, it is difficult to accurately grasp the deterioration state of the discharge element only by the number of times of light emission of the discharge element.

  Therefore, the present invention has been proposed in view of the above-described problems, and an object of the present invention is to provide an SPD with a deterioration alarm function capable of accurately grasping deterioration of a protective element and improving reliability. There is.

  As a technical means for achieving the above-mentioned object, the present invention relates to a gas arrester connected between a power supply terminal and a ground terminal and having a discharge gap, and a gas arrester which is disposed in proximity to the gas arrester and which uses a surge current. An SPD with a deterioration alarm function that includes a light receiving unit that detects light emission at the time of discharging, and determines whether the output from the light receiving unit exceeds a threshold set based on the light emission time of the gas arrester A control unit and a display unit that displays a deterioration alarm based on an output of the control unit are provided.

  In the present invention, focusing on the fact that the light emission time of the gas arrester is proportional to the magnitude of the surge current applied to the gas arrester, the threshold value for determining the deterioration state is set based on the light emission time of the gas arrester. As this threshold value, if the light emission of the gas arrester is longer than or equal to a predetermined time, it can be determined that the surge current applied to the gas arrester is greater than or equal to a predetermined value. When applied. Based on the threshold value set in this way, the deterioration warning is displayed on the display unit with the output of the control unit.

  A structure having a counter that displays the number of times of light emission of the gas arrester based on the output from the light receiving unit in the present invention is desirable. In this way, it is possible to grasp not only the number of times of light emission of the gas arrester but also the magnitude of the surge current based on the light emission time of the gas arrester.

  In the present invention, the first wiring board on which the SPD component including the gas arrester is mounted and the second wiring board on which the light receiving unit, the control unit, and the display unit are mounted are accommodated in the case, The wiring board and the second wiring board are arranged in parallel through a minute gap, and the light receiving part on the second wiring board is formed on the first wiring board with respect to the gas arrester on the first wiring board. A structure in which they are arranged to face each other through the formed window holes is desirable. If it does in this way, it will become easy to arrange a photo acceptance part near to a gas arrester, aiming at effective use of space.

  In the present invention, a structure in which the electric wire terminal is common to the first wiring board and the second wiring board, and a surge cutoff transformer is mounted on the second wiring board and connected to the power supply terminal is desirable. If it does in this way, it can drive with an alternating current power supply, without driving the light-receiving part, control part, and display part which were mounted in the 2nd wiring board with a battery. In this case, it is necessary to convert the AC power source into DC.

  In the present invention, a structure provided with a contact output terminal that sends out deterioration information including an output from the light receiving unit to the outside is desirable. In this way, the deterioration information can be sent to the outside from the contact output terminal, so that remote monitoring based on the deterioration information can be realized.

  According to the present invention, a control unit that determines whether the output from the light receiving unit exceeds a threshold set based on the light emission time of the gas arrester, and a deterioration alarm is displayed based on the output of the control unit. And a control unit that determines whether or not a threshold value set based on the light emission time of the gas arrester proportional to the magnitude of the surge current is exceeded. Display on the display. Thereby, it is possible to accurately grasp the deterioration of the gas arrester and improve the reliability of the SPD.

In embodiment of this invention, it is a block diagram which shows schematic circuit structure of SPD with a deterioration warning function. It is a flowchart for demonstrating the counter function and deterioration warning function in SPD. It is a characteristic view which shows the relationship between the magnitude | size of a surge current, and the light emission time at the time of discharge of a gas arrester. FIG. 4A is a front view as viewed from the upper side of the SPD, and FIG. 5B is a rear view as viewed from the lower side of the SPD. FIG. 2A is a front view seen from the upper side of the SPD, and FIG. 2B is a rear view seen from the lower side of the SPD. It is a side view which shows the state before attaching a 1st wiring board and a 2nd wiring board. It is a side view showing a state after assembling the first wiring board and the second wiring board. It is sectional drawing which shows the state which integrated the 1st wiring board and the 2nd wiring board in the case. It is a front view which shows the front surface of the case incorporating the 1st wiring board and the 2nd wiring board.

  An embodiment of an SPD with a deterioration warning function according to the present invention will be described in detail below with reference to the drawings. In the following embodiments, a function is provided that is installed inside a distribution board connected to an AC single-phase three-wire system or an AC three-phase three-wire distribution line and warns the deterioration of a varistor or gas arrester that is a protective element. An SPD provided is illustrated. In the following embodiment, an SPD having a circuit configuration with a varistor and a gas arrester will be described. However, an SPD having a circuit configuration with only a gas arrester is also applicable.

  FIG. 1 shows a schematic circuit configuration of an SPD according to an embodiment of the present invention. This SPD is connected between three power supply terminals 1 to 3 and one ground terminal 4 as shown in the figure, and includes thermal fuses 5 to 7 made of a low melting metal alloy, and a varistor mainly composed of ZnO. 8 to 11 and a gas arrester 12 having a discharge gap are configured as main components.

  That is, a series circuit of the thermal fuses 5 to 7 and the varistors 8 to 10 is connected to each of the power supply terminals 1 to 3, the varistor side of each series circuit is connected in common, and the common connection point and the ground terminal 4 are connected. A series circuit of a varistor 11 and a gas arrester 12 is connected between them. The line varistors 8 to 10 between the power supply terminals 1 to 3 share and absorb the line-to-line surge equally, and one varistor 8 to 10 between the terminals, and a common varistor 11 between the connection midpoint and the ground terminal 4. And absorbs ground surge.

  Two operation lamps (LEDs) 13 and 14 are connected between the connection point of the thermal fuse 5 and the varistor 8, the connection point of the thermal fuse 6 and the varistor 9, and the connection point of the thermal fuse 7 and the varistor 10. Each is connected. Although not shown, the operation lamps 13 and 14 are provided with a protection diode for protecting against a voltage in the reverse direction to that of a commonly used protection resistor. At normal times, the operation lamps 13 and 14 are lit. The thermal fuses 5 to 7 are arranged at positions close to the varistors 8 to 11 and are blown when abnormal heat generation due to deterioration of the varistors 8 to 11 is detected. The operation lamps 13 and 14 are disconnected from the power supply terminals 1 to 3 by the melting of the temperature fuses 5 to 7 so that the operation lamps 13 and 14 are turned off. When the operation lamps 13 and 14 are turned off, the complete deterioration of the varistors 8 to 11 is displayed.

  In addition to the SPD configuration circuit 15 described above, the SPD of this embodiment includes a control circuit 16 that exhibits a surge count function and a deterioration alarm function. The control circuit 16 is disposed in the vicinity of the gas arrester 12, and a phototransistor 17 that is a light receiving unit that detects light emission during discharge of the gas arrester 12 due to a surge current, and a counter 19 and an alarm based on the output from the phototransistor 17. A CPU 18 that is a control unit that controls a lamp (LED) 20, a counter 19 that is a count indicator such as a 7-segment display that displays the number of times of light emission of the gas arrester 12 based on the output of the CPU 18, and an output of the CPU 18 The alarm lamp 20 which is a display unit for displaying a deterioration alarm by emitting light, the complete deterioration of the varistors 8 to 11 when the operation lamps 13 and 14 are turned off, the number of times of light emission of the gas arrester 12 by the display of the counter 19, and the alarm lamp 20 Information such as deterioration alarms of varistors 8-11 due to lighting of external signals ; And a contact output terminal 21 for outputting.

  The wire terminals 1 and 2 of the SPD component circuit 15 are shared by the control circuit 16, the primary side of the surge cutoff transformer 22 is connected to the power supply terminals 1 and 2, and the rectifier circuit 23 is connected to the secondary side of the transformer 22. The power is supplied to the CPU 18, the counter 19 and the alarm lamp 20 via the voltage adjustment circuit 24. Thus, by making the power supply terminals 1 and 2 common between the SPD configuration circuit 15 and the control circuit 16, it is possible to supply a power supply voltage to the control circuit 16 without using a battery for the control circuit 16.

  In the SPD configured as described above, as described above, the temperature fuses 5 to 7 are blown by the abnormal heat generation due to the complete deterioration of the varistors 8 to 11 and the operation lamps 13 and 14 are extinguished, but the varistors 8 to 11 are completely deteriorated. In normal times until the operation lamps 13 and 14 are lit, if a surge current due to a lightning strike flows from the power supply terminals 1 to 3 to the ground terminal 4, the gas arrester 12 emits light by discharge.

  Light emission during discharge of the gas arrester 12 due to the surge current is detected by the phototransistor 17 (see STEP 1 in FIG. 2). The CPU 18 calculates the number of times of light emission of the gas arrester 12 based on the output from the phototransistor 17 (see STEP 2 in FIG. 2). Based on the output from the CPU 18, the counter 19 displays the number of times of light emission of the gas arrester 12. Here, as shown in FIG. 3, the light emission time of the gas arrester 12 is substantially proportional to the magnitude of the current flowing through the varistors 8 to 11 and the gas arrester 12 from a small current region to a considerably large current region. Increase.

  Therefore, the CPU 18 sets a threshold value for determining the deterioration state based on the light emission time of the gas arrester 12. As this threshold value, when the light emission of the gas arrester 12 is 10 ms or more, it can be determined that the surge current Imax applied to the varistors 8 to 11 and the gas arrester 12 is 10 kA or more (see FIG. 3). When the emission time 10 ms of the gas arrester 12 is detected three times (see STEP 3 and 4 in FIG. 2), it is determined that a surge current of 10 kA or more has been processed three times. Based on the threshold value thus set, the alarm lamp 20 is turned on by the output of the CPU 18 to display a deterioration alarm (see STEP 5 in FIG. 2). The above threshold value is an example, and the setting of the light emission time and the number of detections of the gas arrester 12 is arbitrary.

  Thus, based on the light emission time of the gas arrester 12 proportional to the magnitude of the surge current by grasping the magnitude of the surge current based on the light emission time of the gas arrester 12 as well as the number of times of light emission of the gas arrester 12. The CPU 18 determines whether or not the set threshold value is exceeded, and displays a deterioration alarm by turning on the alarm lamp 20 based on the determination result, thereby accurately determining the deterioration of the varistors 8 to 11 and the gas arrester 12. It is possible to grasp and improve the reliability of the SPD.

  As shown in FIGS. 4A and 4B, the SPD includes a first wiring board 31 on which SPD components including the varistors 8 to 11 and the gas arrester 12 are mounted, and FIGS. 5A and 5B. As shown, a phototransistor 17, a CPU 18, and a second wiring board 32 on which an alarm lamp 20 is mounted are provided. The first wiring board 31 constitutes the SPD component circuit 15 and the second wiring board 32 constitutes the control circuit 16 (see FIG. 1).

  As shown in FIGS. 4A and 4B, the first wiring board 31 is provided with three power supply terminals 1 to 3 on one side and one ground terminal 4 on the opposite side. Two operation lamps 13 and 14 for displaying complete deterioration are mounted, and four disk-shaped varistors 8 to 11 and one gas arrester 12 are mounted on the back side thereof. The three thermal fuses 5 to 7 are provided as a disconnecting mechanism using a low-melting metal alloy. In addition, a window hole 33 is formed at a portion where the gas arrester 12 is mounted.

  As shown in FIGS. 5A and 5B, the second wiring board 32 has a CPU 18, a 7-segment counter 19 and a warning lamp 20 for displaying a deterioration alarm on the front side, and a phototransistor 17 on the back side. And a transformer 22 is mounted. Two through holes 34 and 35 are formed through which the two operation lamps 13 and 14 mounted on the first wiring board 31 are inserted. A connector 36 connected to the contact output terminal 21 via a lead wire is also provided.

  As shown in FIGS. 6 and 7, the first wiring board 31 and the second wiring board 32 are arranged in parallel through a minute gap. At this time, the phototransistor 17 on the second wiring board 32 is disposed to face the gas arrester 12 on the first wiring board 31 through the window hole 33. As a result, the phototransistor 17 is disposed close to the gas arrester 12. Further, the transformer 22 on the second wiring board 32 is disposed in the notch recess 37 of the first wiring board 31. Further, the operation lamps 13 and 14 on the first wiring board 31 are inserted into the through holes 34 and 35 of the second wiring board 32. In this way, the first wiring board 31 and the second wiring board 32 are arranged to make effective use of space for each component.

  As shown in FIGS. 8 and 9, the first wiring board 31 and the second wiring board 32 are accommodated in a resin case 38. The illustrated case 38 exemplifies a two-part structure of the upper case 39 and the lower case 40, but may have another structure. On the front surface of the case 38, a 7-segment counter 19, operation lamps 13 and 14 for displaying complete deterioration, and an alarm lamp 20 for displaying deterioration alarms are arranged.

  Further, three power supply terminals 1 to 3 are arranged on one side of the case 38, and one ground terminal 4 and contact output terminal 21 are arranged on the opposite side. This contact output terminal 21 sends out deterioration information including the output from the alarm lamp 20 to the outside. The tip of the lead wire 41 extending from the contact output terminal 21 is connected to the connector 36 provided on the second wiring board 32. Is electrically connected to the CPU 18 mounted on the second wiring board 32. Thus, since deterioration information can be sent out from the contact output terminal 21, remote monitoring based on the deterioration information can be realized.

  The present invention is not limited to the above-described embodiments, and can of course be implemented in various forms without departing from the gist of the present invention. It includes the equivalent meanings recited in the claims and the equivalents recited in the claims, and all modifications within the scope.

1 to 3 Power supply terminal 4 Grounding terminal 8 to 11 Varistor 12 Gas arrester 17 Light receiving part (phototransistor)
18 Control unit (CPU)
19 Counter 20 Display (alarm lamp)
21 Contact Output Terminal 22 Surge Breaking Transformer 31 First Wiring Board 32 Second Wiring Board 33 Window Hole

Claims (5)

Deterioration alarm comprising a gas arrester connected between a power supply terminal and a ground terminal and having a discharge gap, and a light receiving portion that is disposed close to the gas arrester and detects light emission during discharge of the gas arrester due to a surge current. SPD with function,
A control unit for determining whether an output from the light receiving unit exceeds a threshold set based on a light emission time of a gas arrester; and a display unit for displaying a deterioration alarm based on the output of the control unit. SPD with deterioration warning function, characterized by   The SPD with a deterioration alarm function according to claim 1, further comprising a counter that displays the number of times of light emission of the gas arrester based on an output from the light receiving unit.   The first wiring board on which the SPD component including the gas arrester is mounted and the second wiring board on which the light receiving unit, the control unit, and the display unit are mounted are accommodated in a case, and the first wiring The board and the second wiring board are arranged in parallel with a minute gap, and the light receiving portion on the second wiring board is formed on the first wiring board with respect to the gas arrester on the first wiring board. The SPD with a deterioration alarm function according to claim 1 or 2, wherein the SPD is disposed so as to face each other through a window hole.   The electric wire terminal is shared by the first wiring board and the second wiring board, and a surge blocking transformer is mounted on the second wiring board and connected to the power supply terminal. SPD with deterioration warning function according to item.   The SPD with a deterioration alarm function according to any one of claims 1 to 4, further comprising a contact output terminal for transmitting deterioration information including an output from the light receiving unit to the outside.

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