JP4176675B2 - Lightning arrestor - Google Patents

Description

  The present invention relates to a lightning arrester that protects an electrical device connected to an electric circuit such as a power supply circuit from an abnormal current such as a lightning surge.

  A lightning arrester used in a power supply circuit or a communication circuit includes a lightning arrester connected between electric circuits or between an electric circuit and the ground. In a lightning arrester, especially a gapless lightning arrester, the characteristics of the lightning arrester are deteriorated due to repeated lightning surges and long-term use. When the characteristics deteriorate and the leakage current of the element increases and the element generates heat, thermal runaway may occur and the lightning arrester may be damaged.

In order to eliminate such a risk, for example, the number of surges applied to the lightning arrester is measured and the degree of deterioration is displayed according to the number of times, or when the number of times reaches a predetermined number, it is determined that the life has expired and an alarm is issued. It has been done. In addition, the deterioration is detected by detecting the leakage current of the lightning protection element, and the occurrence of the deterioration is displayed by causing the light emitting diode to emit light with the leakage current (see, for example, Patent Document 1).
Japanese Patent Laid-Open No. 2003-163106 (FIG. 1)

  The number of discharges of the lightning arrester can be easily measured by detecting the surge current with a transformer and counting it with a counter, and it is easy to operate the relay based on the counter count value and output an alarm. As a result, the entire lightning arrester becomes large and expensive due to the use of a relay, counter, and output relay. Further, if the lightning protection element is damaged by a large surge current while not being discharged until a predetermined number of times of discharge, the counter may stop and the alarm function may not be exhibited. Further, even in a lightning arrester that monitors the deterioration with the leakage current of the lightning arrester, there is a problem that when a large surge current flows and breaks, the leakage current does not flow, and the lightning arrester deterioration display and alarm functions cannot be exhibited.

  The present invention has been made in view of such circumstances, and is a highly reliable lightning arrester capable of reliably separating the lightning arrester from the electric circuit when the lightning arrester is deteriorated or damaged, and capable of displaying and alarming the occurrence of the deterioration or damage. The purpose is to provide.

  The present invention is a lightning arrester incorporating a plurality of lightning arresters connected between power lines of a power line for a three-phase power supply circuit and between each of the power lines and a ground terminal, and the lightning arrester is deteriorated or damaged. Three sets of disconnecting circuits having fuses that are fused and disconnected from the electric circuit are inserted into the power supply line, and an indicator lamp that is connected between the electric circuits via the disconnecting circuit and that indicates the presence or absence of the lightning protection element abnormality is turned on. Two sets of display circuits are provided, and each of the two sets of display circuits is connected in series with a photocoupler that emits light and receives light in response to the supply of a lighting current to the indicator lamp. One output terminal of the two sets of photocouplers is connected to one of the three communication lines of a common set of output circuits having three communication lines for transmitting the output signals of the photocouplers to the outside. Connected to the three communication lines By connecting separately the remaining two of the other of the output terminals of the two pairs of photo couplers, is to achieve the above object.

  Here, the electric circuit is a power line or ground line of a three-phase power circuit or a single-phase power circuit, a wire such as a communication circuit, or a ground line, between three-phase power lines, between single-phase power lines, between a power line and the ground. A lightning protection element is connected to each other, and a disconnection circuit is inserted in each of the electric circuits near the lightning protection element. As the fuse of the disconnection circuit, one or both of a temperature fuse that is blown by heat generation of a deterioration current of a relatively small lightning arrester and a current fuse that is blown by a relatively large abnormal current such as a lightning surge can be applied. The display lamp of the display circuit is a light emitting diode that emits light with high current at a low current of several mA, for example, and a protective diode, a protective resistor, and the like are connected in series to the light emitting diode to constitute a display circuit. In this display circuit, during normal times when the fuse of the disconnect circuit is not blown, a current flows from the electric circuit to the light emitting diode through the protective diode or protective resistor, and the light emitting diode emits light, thereby indicating that the lightning protection element is normal. A photocoupler and an output circuit are connected to this display circuit.

  The photocoupler is not limited to a photocoupler provided with a light emitting element, for example, a light emitting diode and a phototransistor as a light receiving element, but with a low current such as a photomoss relay or a photothyristor provided with a light emitting diode, a photovoltaic element, and a MOS transistor. Includes semiconductor devices that operate. The light-emitting element of the photocoupler is turned on when the lightning protection element is normal, similarly to the display light-emitting diode of the display circuit, and is turned off when the lightning protection element deteriorates beyond a predetermined level or is damaged. As a warning signal for notifying that the lightning protection element is in an abnormal state due to the extinguishing of the lightning, it is output to the output circuit. The output circuit can be configured by a simple circuit in which output terminals are connected to a plurality of communication lines for transmitting a signal indicating whether or not the lightning protection element is normal to a remote monitoring control unit. Further, by connecting the photocoupler and the output circuit to the display circuit, it is possible to achieve a circuit configuration that is driven with the same low voltage and low current as the display circuit, and simplification of the circuit and low-cost design are facilitated.

  In the present invention, the disconnecting circuit is a series circuit of a temperature fuse that is blown by heat generation due to deterioration of the lightning arrester and a current fuse that is blown by an abnormal current that exceeds the surge resistance of the lightning arrester and is damaged. Can do. If the circuit is a power system with a relatively large abnormal current (such as a lightning surge current) such as a three-phase power circuit, connect a temperature fuse and a current fuse in series to the disconnect circuit to generate a large abnormal current. When it arrives, the current fuse is surely blown to disconnect the lightning protection element from the circuit, and when the lightning protection element generates heat due to the leakage current due to the characteristic deterioration that does not cause the current fuse to blow, the temperature fuse is blown to disconnect the lightning protection element from the circuit. By doing so, it is possible to realize a lightning arrester that can reliably cope with surge current and leakage current.

  In the present invention, a surge absorbing element that discharges an abnormal current that enters the communication line from an external monitoring control unit or the like can be installed between the communication lines of the output circuit. This surge absorbing element is the same as a lightning protection element connected between electric circuits or between an electric circuit and the ground, and is called differently here in order to clearly distinguish them. By connecting a surge absorbing element between the communication lines of the output circuit, the photocoupler and the display circuit are protected from an abnormal current coming through the communication line, and the operation of the photocoupler and the display circuit is stabilized.

  In the present invention, the photocoupler and the output circuit are mounted on one substrate to constitute one independent first circuit unit, and further, the lightning protection element, the disconnecting circuit and the display circuit connected between the electric circuits are provided. A second circuit unit is configured by mounting on another board, and the first and second circuit units are connected in two upper and lower stages and wired to form one board unit, which is incorporated into a lightning arrester. be able to.

  As described above, the first circuit unit in which the photocoupler and the output circuit are mounted on one substrate can be manufactured and assembled as an independent single product, and can be changed to other types of electric circuits as a single product. In addition, by connecting the first and second circuit units in two upper and lower stages and wiring them together, the entire lightning arrester can be made compact and easy to store in one compact insulating outer case. become. As the insulating outer case in this case, a compact case integrally having a plurality of types of terminal blocks including a terminal block for wiring with the electric circuit can be applied.

  According to the present invention, a photo for outputting a signal indicating whether or not a lightning arrester is normal to a display circuit that displays the presence or absence of deterioration or damage of a lightning arrester installed between electric circuits or between an electric circuit and the ground. Because the coupler and output circuit are connected, the photocoupler and output circuit can be configured with circuit components that drive at the same low voltage and low current as the display circuit. There is an excellent effect that simplification of the circuit and low-cost design are possible. In addition, even if the lightning arrester is momentarily damaged due to lightning surge, etc., the fuse blows and breaks the lightning arrester reliably from the electric circuit, and the display circuit and the photocoupler are reliably stopped. It is possible to provide stable lightning arrester normality presence / absence indications and to output lightning failure alarms, and to provide a highly reliable lightning arrester.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

  FIG. 1A shows a connection between each circuit of the U-phase power supply line La, V-phase power supply line Lb, and W-phase power supply line Lc of the three-phase AC power supply circuit, and between each circuit and the ground terminal E. It is a circuit diagram which shows the outline | summary of the lightning arrester 1 incorporating the some lightning arrester 2 (not shown). 2 and 3 are perspective views of the board unit 20 in which the lightning arrester 1 of FIG. 1A is mounted and assembled on two boards, and reference numeral 2 denotes a lightning arrester. 4 and 5 are diagrams showing an example of the appearance of a lightning arrester in which the board unit 20 is housed in one insulating outer case 30. FIG.

  The lightning arrester 1 shown in FIG. 1A includes three sets of disconnecting circuits 3 having fuses F inserted in the power supply lines La, Lb, and Lc, and two sets of display circuits 4-1 connected between the power supply lines, 4-2. 1A shows only one fuse F. In the case of the lightning arrester 1 for a three-phase power supply circuit, as shown in FIG. 1B, there are two types of fuses, a current fuse Fa and a thermal fuse Fb. Are preferably connected in series to form the disconnect circuit 3. In other power supply circuits and communication circuits where the abnormal current level flowing through the lightning arrester 2 is low, the lightning arrester 2 is very unlikely to be damaged, so the current fuse Fa is omitted and only the thermal fuse Fb is disconnected. The circuit 3 may be formed.

  The display circuits 4-1 and 4-2 in FIG. 1A are series circuits of a display light emitting diode (hereinafter referred to as LED), a protection diode D, a protection resistor R, and a smoothing capacitor C. The LED is lit with a low current due to the low voltage divided by the resistor R, the protective diode D, and the like. When the lightning protection element is not deteriorated to a problem level and the fuse F is in a normal state where it does not operate, the LED is turned on and a normal display is performed.

In the lightning arrester 1 of FIG. 1A, photocouplers 5-1 and 5-2 are connected in series to two sets of display circuits 4-1 and 4-2, and the two sets of photocouplers 5-1 and 5-2. -2 and a common set of output circuits 6 are connected in series. Each of the two sets of photocouplers 5-1 and 5-2 is configured by optically coupling a light emitting diode 5 a as a light emitting element and a phototransistor 5 b as a light receiving element that receives and outputs the emitted light. The light emitting diode 5a is connected in parallel to the smoothing capacitor C, and the photocouplers 5-1 and 5-2 are connected in series to the display circuits 4-1 and 4-2. The output circuit 6 includes three communication lines L1, L2, and L3 that transmit output signals from the phototransistors 5b of the two sets of photocouplers 5-1 and 5-2 to the external monitoring control unit 8. Each of the communication lines L1, L2, and L3 is inserted with a resistor R ′, and includes output terminals 7-1, 7-2, and 7-3 at the ends. One communication line L2 is connected to one output terminal of two sets of photocouplers 5-1, 5-2, and the remaining two communication lines L1, L3 are connected to two sets of photocouplers 5-1, 5-2. -2 are connected separately to the other output terminals. Bidirectional silicon surge protection elements 9-1 and 9-2 and a gas-filled triode arrester 10 are connected between the communication lines L1, L2, and L3. In this example, the silicon surge protection elements 9-1 and 9-2 are inserted between the communication lines L1 and L2 and between the communication lines L1 and L3, respectively, but may be inserted between the communication lines L2 and L3. It is valid.

  Next, an operation when the lightning arrester 1 having the above circuit configuration is applied to, for example, a three-phase power supply line will be described. In this case, an output indicating a normal or abnormal state of the lightning arrester 1 is obtained between the communication lines L3 and L1.

  In a normal state where no surge current enters any of the three-phase power supply lines La, Lb, and Lc, and the lightning protection element 2 is not deteriorated, it is connected to each of the power supply lines La, Lb, and Lc. In addition, the fuses F are not blown and current flows to the LEDs through the smoothing capacitors C, the protective resistors R, and the protective diodes D in the two sets of display circuits 4, the LEDs are lit, and the lightning arrester 1 is in a normal state. Display that there is. At this time, since the smoothing capacitor C is charged, the light emitting diodes 5a of the photocouplers 5-1 and 5-2 connected in parallel to each other are energized to emit light. The phototransistor 5b optically coupled to each other is turned on by the light emission of the light emitting diode 5a, and the terminals 7-3 and 7-1 of the output circuit 6 are turned on, indicating that the lightning protection element 2 is normal. An output signal is obtained and transmitted to the monitoring control unit 8 through the communication lines L3 and L1.

  When a lightning surge enters one of the power supply lines La, Lb, Lc, for example, the power supply line La, an excessive current exceeding the withstand current flows in the corresponding element of the lightning protection element 2, and at least one of the fuses F is blown. The lines Lb and La are electrically disconnected, the power supply to the display circuit 4-1 is cut off, and the LED is turned off. Thereby, it is displayed that the lightning protection element 2 is damaged or is not functioning. When the energization of the display circuit 4-1 is stopped, the smoothing capacitor C in the circuit is not charged, and the current supply to the light emitting diode 5a of the photocoupler 5-1 is stopped. As a result, the light emitting diode 5a is turned off, the phototransistor 5b optically coupled thereto is turned off, the output terminals 7-3 and 7-1 of the output circuit 6 are turned off, and the lightning protection element 2 is connected to the communication lines L3 and L1. An output signal indicating that is in an abnormal state is obtained and sent to the monitoring control unit 8.

  In the lightning protection element 2, when an abnormality occurs in the element connected to the power supply line Lb, the display circuits 4-1 and 4-2 are turned off, so that the photocouplers 5-1 and 5-2 are turned off. An output signal indicating that an abnormal state has occurred is generated between the communication lines L3 and L1. Further, when a failure occurs in the lightning arrester connected to the power supply line Lc, the photocoupler 5-2 is turned off, and an alarm signal indicating the occurrence of an abnormality is sent to the monitoring control unit 8 through the communication lines L3 and L1.

  Of course, when the fuse F is used alone or connected in series with the current fuse, heat generation due to deterioration of the characteristics of the lightning protection element 1 is detected, and when the surface temperature reaches the set value, The fuse is blown, and the deteriorated lightning arrester is disconnected from the power line. As a result, one or both of the corresponding display circuits 4-1 and 4-2 are turned off, and an output signal indicating an abnormal state is generated between the communication lines L3 and L1 in the same manner as described above. To do.

  In addition, when power is supplied in a single phase using the power supply lines La and Lb, whether the LED of the display circuit 4-1 is turned on or off indicates whether a normal state or an abnormal state has occurred. In response to this, the photocoupler 5-1 is turned on or off, and an output signal indicating normality or abnormality is generated between the output terminals 7-2 and 7-1 of the output circuit 6, and is monitored through the communication lines L2 and L1. The output signal is transmitted to the control unit 8.

  By the way, in this apparatus, by adopting a configuration in which the normal or abnormal state of the lightning protection element 2 is remotely transmitted to the monitoring control unit 8 through the communication lines L1, L2, and L3, a surge is transmitted through these communication lines L1, L2, and L3. There is a risk of arrival. In response to this surge, the bidirectional silicon surge protection element 9-1 or surge protection element 9-2 in the output circuit 6 and the gas-filled triode arrester 10 are electrically connected, and the photocouplers 5-1, 5-2. Is protected from surge, and further, the influence on the power supply lines La, Lb, and Lc is substantially prevented.

  The lightning arrester 1 having the above circuit configuration may be manufactured and assembled with the structure of the substrate unit 20 as shown in FIGS. 2 and 3, for example. The substrate unit 20 includes a first circuit unit 21 in which two sets of photocouplers 5 and an output circuit 6 are mounted on a first substrate 11, three sets of separation circuits 3, and two sets of display circuits 4 as a second substrate. 12, the second circuit unit 22 mounted on 12 is integrated by connecting it in two upper and lower stages. The two substrates 11 and 12 are printed wiring boards, the photocoupler 5 and the output circuit components are mounted on the lower surface of the first substrate 11 in FIG. 2, and a pair of LEDs are mounted on the upper surface of the second substrate 12 in FIG. The display circuit components except the fuse F and the LED are mounted on the lower surface. The two substrates 11 and 12 are connected by a plurality of wiring support columns 13 and face each other in parallel at a predetermined interval. The pair of LEDs protruding from the upper surface of the second substrate 12 protrudes from the upper surface of the first substrate 11. As shown in FIG. 3, the fuse F and the lightning arrester 2 are disposed on the lower surface of the second substrate 12.

  The plurality of lightning protection elements 2 shown in FIG. 3 include a rectangular box-shaped discharge gap element in addition to a disk-shaped arrester element. The disc-shaped lightning protection element 2 is installed on the second substrate 12 in a vertically placed specification substantially perpendicular to the substrate 12. There are two types of fuses F: a current fuse Fa in which a fuse element is inserted into a straight glass tube and both ends of the glass tube are sealed with metal caps, and a thermal fuse Fb in which the fuse element is sealed with resin. 2 is installed on the second substrate 12 in a vertical installation specification. The thermal fuse Fb is installed in contact with or in close proximity to the disc-shaped lightning protection element 2 so that the thermal fuse Fb responds accurately due to heat generated by the deterioration of the lightning protection element 2.

  The outer case 30 shown in FIG. 4 and FIG. 5 is a resin-made lower case 30a and upper case 30b combined in a separable manner, and positions and stores the substrate unit 20 in the internal space. The outer case 30 integrally includes an electric circuit terminal block 31, a signal line terminal block 32, and a grounding terminal block 33, and has a pair of display window holes 34 through which the LED looks into the upper case 30b. Three-phase power lines La, Lb, and Lc are formed on the electric circuit terminal block 31 with a threaded structure, and the output terminal 7 of the output circuit 6 is formed on the signal line terminal block 32 with an electric wire insertion structure. Each terminal block 31, 32, 33 is insulated and protected by a transparent insulating cover 35 that is detachably attached to the outer case 30. The substrate unit 20 is accommodated in such an exterior case 30 with the first substrate 11 facing upward, and a pair of LEDs protruding from the upper surface of the first substrate 11 is located in the back of the display window hole 34. The fuse F and the lightning protection element 2 projecting on the lower surface of the second substrate 12 are positioned near the bottom surface of the outer case 30. By doing so, the substrate unit 20 and the outer case 30 are small and compact. It will be a thing.

  In addition, the lightning arrester of this invention is not limited to above-described embodiment, Of course, a various change can be added in the range which does not deviate from the summary of this invention.

The lightning arrester shown in the circuit of FIG. 1 is applied to a three-phase power circuit, but this lightning arrester can be applied to a two-phase power circuit. For example, by using the two communication lines L1 and L2 of the display circuit 4-1 and the output circuit 6 installed between the two power supply lines La and Lb in FIG. Can be used.

(A) is a circuit diagram which shows the outline | summary of the lightning arrester which concerns on this invention, (B) is a circuit diagram which shows an example of a disconnection circuit. It is a perspective view of the board | substrate unit in the lightning arrester of FIG. It is a perspective view from the lower surface side of the board | substrate unit of FIG. It is a perspective view of the whole lightning arrester of FIG. It is a side view including the partial cross section of the lightning arrester of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Lightning arrester 2 Lightning arrester 3 Disconnection circuit 4-1, 4-2 Display circuit 5-1, 5-2 Photocoupler 6 Output circuit 7-1, 7-2, 7-3 Output terminal 8 Monitoring control part 9-1, 9-2 Bidirectional Silicon Surge Absorber 10 Surge Absorber, Gas-filled Triode Arrestor 20 Substrate Unit 11 First Substrate 12 Second Substrate 21 First Circuit Unit 22 Second Circuit Unit 30 Insulating Exterior Case 31, 32, 33 Terminal block 34 Display window hole F Fuse Fa Current fuse Fb Thermal fuse L1 to L3 Communication line La to Lc Power supply line LED Light emitting diode for display

Claims (4)

A lightning arrester incorporating a plurality of lightning arresters connected between power lines for a three-phase power supply circuit and between each power circuit and a ground terminal. Three sets of disconnection circuits having fuses that are disconnected from the power supply line are inserted into the power supply line, and two sets of displays for lighting the indicator lamps connected between the electric circuits via the disconnection circuit and indicating the presence or absence of the lightning protection element abnormality Circuit,
Each of the two sets of display circuits is connected in series with a photocoupler that emits and receives light in response to a lighting current supplied to the indicator lamp, and outputs the output signals of the two sets of photocouplers to the outside. One of the three communication lines of a common set of output circuits having three communication lines for transmission is connected to one output terminal of the two sets of photocouplers, and the three communication lines are connected. A lightning arrester characterized in that the remaining two wires are connected separately to the other output terminals of the two sets of photocouplers.   Each of the three sets of disconnecting circuits is a series circuit of a temperature fuse that is blown by heat generation due to deterioration of the lightning arrester and a current fuse that is blown by an abnormal current having a magnitude that damages the lightning arrester. Item 1. The lightning arrester according to item 1.   The lightning arrester according to claim 1 or 2, wherein a surge absorbing element that protects the photocoupler from an abnormal current entering the communication line is installed between the three communication lines of the output circuit.   A first circuit unit in which a set of output circuits common to the two sets of photocouplers is mounted on a first board, the lightning protection element, three sets of disconnecting circuits, and two sets of display circuits are connected to a second board. A plurality of types of terminal blocks including a wiring terminal block connected to the electric circuit are integrated into a board unit in which the second circuit unit mounted on the circuit board is connected in two upper and lower stages with the first circuit unit facing up. 4. The lightning arrester according to claim 3, wherein the lightning arrester is housed in an insulating outer case.