JP5220530B2 - Surge protection device - Google Patents

Description

  The present invention relates to a surge protection device, and more particularly to a surge protection device for preventing power supply to a protection target device from being stopped when a SPD (Surge Protection Device surge protection device) included in the surge protection device fails.

The SPD is a device intended to limit transient overvoltage and shunt the surge current to ground, and incorporates a non-linear element.
The non-linear element that constitutes the SPD has a resistance value that varies depending on the voltage across the element. When the voltage across the element is low, the resistance is high and hardly conducts, but when the voltage across the element increases, the resistance value decreases. have. Therefore, when a lightning surge enters the feeder line, the surge current is shunted to the ground, and the protection target device can be protected.

  However, when the SPD deteriorates, the resistance value may decrease and leakage current may occur even when the commercial power input is in a normal state. After the SPD is heated and thermal runaway occurs, a failure mode occurs in which the power supply lines are short-circuited and the SPD ruptures. Can be assumed. In the failure mode, for example, when a voltage-limited MOV (metal oxide varistor such as a metal oxide varistor) is used for the SPD, the MOV has a characteristic that the resistance value decreases as the temperature increases. When the MOV continues to rise in temperature for a long time and the MOV continues to rise in temperature, the resistance value of the MOV will become even lower, eventually becoming short-circuited and then ruptured from the temperature distribution difference inside the MOV, and then opened There is. Therefore, the JIS standard recommends that, for example, a breaker or a fuse is provided in series as an SPD separator (a protective device for separating the SPD when the SPD fails).

  As a prior art, Patent Document 1 describes a power line between two lightning protection devices connected in parallel between a power line that is introduced from the outside and energizes an electric device provided indoors while suppressing a voltage drop during normal operation. A lightning protection device decoupling device capable of simply and properly coordinating current withstand capability is disclosed.

Further, in Patent Document 2, since both ends of the power supply path and the communication line as the surge intrusion path are equipotential before the surge enters the structure, the surge passes through each structure. A surge protection system that suppresses the penetration of surges into a plurality of structures is disclosed.
Furthermore, in Patent Document 3, since the two disconnecting functions consisting of the thermal fuse function and the current fuse function are separated from each other by the thermal fuse and the disconnecting conductor, it is easy to select a thermal fuse with sufficient mechanical strength. An SPD for direct lightning that exhibits stable shut-off performance against surge is disclosed.

FIG. 6 is a configuration diagram of a conventional surge protection device in a three-wire power feeding method (TN type).
For example, as shown in the figure, conventional surge protection devices include SPDs 1-1, 1-2, and 1-3, separators 2-1, 2-2, and 2-3 using thermal fuses and breakers, and an input breaker 3. A ground line 4-1, power supply lines 4-2, 4-3 and 4-4, and an SPD separator 17. The SPD separator 17 is, for example, a breaker having an overcurrent cutoff function for each system. In this example, the protection target device 10 is supplied with power by the power supply lines 4-2 and 4-4 (the power supply line 4-1 is grounded). Note that the TN system is a power feeding system in which the system ground that prevents high voltage from being applied to the high and low voltage portions of the distribution transformer and the equipment ground that protects the load device connected to the low piezoelectric path are equipotentially connected to the ground line. It is. That is, the system grounding is extended to the load device by the grounding wire and used as equipment grounding.
JP 2007-068342 A JP 2007-074803 A JP 2007-288114 A

  In the prior art, for example, a surge protection device as shown in FIG. 6 includes, for example, an SPD 1-1 and a separator 2-1 (such as a thermal fuse for SPD protection), and an SPD separator 17 includes a power supply line 4-4. It is directly connected between the ground wires 4-1. Therefore, for example, when SPD 1-1 fails and becomes low resistance, a short circuit occurs between the feed line 4-4 and the ground line 4-1, and depending on the resistance value at the time of failure of SPD 1-1, a large current is generated in SPD 1-1. Flow, rupture or fire may occur. In the separator (such as a thermal fuse for SPD protection) 2-1, when a small amount of current flows for a long time and the SPD 1-1 generates heat, it is possible to shut off the SPD 1-1 from the power supply line 4-4. Cannot be blocked. Therefore, a circuit breaker (breaker or the like), a current fuse, or the like is used as the SPD separator 17 between the SPD 1-1 and the feeder line 4-4. The same applies between the feeder line 4-3 and the ground line 4-1, and between the feeder line 4-2 and the ground line 4-1. However, when the rated current of the breaker or fuse of the SPD separator 17 considering lightning surge resistance is larger than the rated capacity of the input breaker 3 of the protection target device 10, the SPD fault current causes the SPD separator 17 to In some cases, the input breaker 3 having a small rated current may be cut off earlier than the SPD separator 17 and the power supply to the protection target device 10 may be cut off. In addition, since the trip coil is built in the breaker for overcurrent interruption, in addition to the SPD 1-1, 1-2 and 1-3, the trip coil is also used in the SPD separator 17 by lightning surge. An overvoltage is generated due to an increase in connection resistance due to the floating of the contact. Therefore, there is a case where an adverse effect (for example, damage) is given to the protection target device 10.

  As described above, in the prior art as shown in FIG. 6, the SPD separator 17 is used for the SPDs 1-1, 1-2, and 1-3 installed at the lower level of the input breaker 3 of the protection target device 10. Since the SPD 1-1, 1-2, or 1-3 deteriorates and becomes a low resistance body, the input breaker 3 of the protection target device 10 is ahead of the SPD separator 17 depending on the fault current that flows. There is a case that it shuts off.

In addition, when a conventional fuse or breaker is used for the SPD separator 17, there are the following problems.
When a breaker is used for the SPD separator 17, the SPD 1-1, 1-2, or 1-3 is deteriorated, and depending on the fault current that flows when it becomes a low resistance body, the input breaker of the protection target device 10 than the SPD separator 17. 3 may be cut off first.
Further, when the lightning surge resistance is provided, the rated capacity (rated current) of the SPD separator 17 is larger than that of the input breaker 3 of the protection target device 10, and the protection target device 10 is in an SPD degradation failure in a commercial power input state. There is a case where protection cooperation with the input breaker 3 cannot be obtained. That is, the case where protection cooperation cannot be taken here is, for example, a case where the input breaker 3 cuts off the electric circuit before the breaker used as the SPD separator 17 and power is not supplied to the protection target device 10.

In general, the breaker has a built-in coil to operate a trip mechanism that disconnects the contact when overcurrent occurs. Since the electromagnetic force generated in the coil is proportional to the number of turns of the coil and the current, the smaller the rated capacity (rated current) of the breaker, the greater the number of turns of the coil for operating the trip mechanism. As a result, the impedance increases, and even if a large current flows through the breaker for a moment due to a lightning surge, the breaker may malfunction (trip or contact lift).
When a breaker is used for the SPD separator 17, when a lightning surge current flows through the SPD 1-1, 1-2 or 1-3, the breaker used as the SPD separator 17 has a large impedance, so the SPD 1-1 or 1 In addition to -2 or 1-3, the breaker (SPD separator 17) may generate a large overvoltage or malfunction (open operation).

  On the other hand, when a fuse is used for the SPD separator 17, in order to make it difficult to blow the fuse due to lightning surge current, for example, it is necessary to increase the wire diameter of the fuse element, and as the wire diameter increases, the surface area of the fuse element increases. Therefore, the heat dissipation is improved, and the fuse is difficult to blow at a small current, and the rated capacity increases. For this reason, when the lightning surge resistance is provided, the rated capacity becomes larger than the input breaker 3 of the protection target device 10, and protection coordination with the input breaker 3 of the protection target device 10 is not possible when the SPD deterioration failure occurs in the commercial power supply input state. There is a case. As described above, that is, when the protection coordination cannot be obtained here, for example, the input breaker 3 cuts off the electric circuit before the fuse used as the SPD separator 17 and power is not supplied to the protection target device 10. Is the case.

In addition, since the fuse cuts off the electric circuit in a short time, the time required for the current flowing through the fuse to become zero from the peak current is short. As a result, the rate of current change with time increases, and a large back electromotive force is generated when the fuse is blown. For this reason, when a fuse is used for the SPD separator 17, the SPD 1-1, 1-2, or 1-3 deteriorates and fails in the commercial power supply input state, and a large current (short-circuit current) flows between the feeder lines. When the SPD separator 17) operates, a large jump voltage is generated at the time of interruption, and an overvoltage is applied to the device to be protected 10 and the device may be damaged or adversely affected.
In the case of a breaker, since the interruption is a mechanical operation of the contact, the interruption time is long and the back electromotive force is small.

  In view of the above, the present invention provides a series circuit of an SPD and a separator (such as a thermal fuse for SPD protection) between the other end of the SPD whose one end is connected to the power supply line and the ground line, and a protection target device. A circuit in which a circuit protector (drive unit) having a smaller rated current than the input breaker is connected in parallel is attached, and a blocking unit is provided between each power supply line and each SPD. When the SPD breaks down and becomes low resistance, the fault current between the power supply line and the ground line at the time of SPD failure can be quickly cut off by the cut-off unit driven by the circuit protector. One of the purposes is to prevent malfunctions (false interruptions).

The present invention also provides an SPD separator for lightning surges by using a breaker with a small inductance and resistance instead of using a breaker with a large inductance and a built-in coil breaker or a current fuse with a large resistance. One of the purposes is to reduce the overvoltage generated in the circuit.
Furthermore, according to the present invention, the SPD is separated from the power supply line at the time of SPD failure by using a circuit protector having a low rated current, so that the maximum current flowing in the SPD at the time of interruption can be suppressed, and the mechanical contact of the circuit protector is interrupted. Since the time is long, the induced electromotive force generated by the time change of the rapid current generated when the conventional SPD separation fuse or breaker is cut off can be reduced, so that the voltage jump generated when the SPD is separated from the power supply line can be reduced. One of the purposes is to reduce.

According to the first solution of the present invention,
An ungrounded first power supply line for supplying electricity to the protection target device on the protection target device side;
A grounding wire that is grounded on the power supply side and supplied to the device to be protected;
An ungrounded second feeder on the power supply side;
An input breaker provided between the ungrounded first power supply line and the second power supply line, for connecting or disconnecting the first power supply line and the second power supply line;
A first switch, a first separator, a first surge protection device, and a second surge protection device provided in series between the first power supply line and the ground line on the protection target device side And a second separator;
A drive unit that is provided in parallel with a series circuit of the second surge protection device and the second separator, and operates to shut off the shut-off unit;
With
Upon failure of the first surge protection device, a short-circuit current passing through the first surge protection device is transferred from the first feeder to the first switch of the interrupting unit, the first separator, the first 1 surge protection device, a surge that is caused to flow to the ground line through the drive unit, so that the drive unit drives the first switch of the blocking unit and disconnects it before the input breaker. A protective device is provided.

  Conventionally, when the SPD breaks down and becomes low resistance, a short circuit occurs between the power supply line and the ground line. When a large current flows through the SPD, the SPD protection temperature fuse cannot separate the SPD in a short time, and thus the SPD may rupture or fire. However, according to the present invention, an SPD and a separator (such as a thermal fuse for SPD protection) are connected between the other end of the SPD whose one end is connected to the feeder line and the ground line, and an input breaker of the protection target device. By installing a circuit that is connected in parallel with a circuit protector with a small rated current, the fault current between the power supply line and the grounding line at the time of SPD failure can be quickly shut off at the shut-off unit driven by the circuit protector. It is possible to prevent malfunction (erroneous interruption) of the input breaker of the protection target device due to the SPD failure.

Further, according to the present invention, instead of using a breaker having a large inductance and a built-in coil or a current fuse having a large resistance, an SPD separator having a small inductance and resistance can be used to perform SPD separation by lightning surge. Overvoltage generated in the device can be reduced.
Furthermore, according to the present invention, the SPD is separated from the power supply line when an SPD failure occurs by using a circuit protector with a low rated current, so that the maximum current flowing in the SPD at the time of interruption can be suppressed and the mechanical contact of the circuit protector can be reduced. The voltage generated when the SPD is separated from the power supply line because the induced electromotive force generated by the time change of the rapid current that has occurred at the time of the interruption in the conventional SPD separation fuse or breaker can be reduced because the interruption time is long. Bounce can be reduced.

1. Configuration FIG. 1 is a configuration diagram of a surge protection device according to the present embodiment.
This embodiment is an example applied to a three-wire power feeding method (TN type). The TN system is a power feeding system in which the system ground that prevents high voltage from being applied to the low voltage portion of the distribution transformer and the equipment ground that protects the load device connected to the low piezoelectric path are made equipotential with the ground line. is there. That is, the system grounding is extended to the load device by the grounding wire and used as equipment grounding. The present invention is not limited to these, and can be applied as appropriate to a two-wire system or other power feeding method in which system grounding and equipment grounding are equipotential with a grounding wire.

The surge protection device according to the present embodiment includes, for example, SPD 1-1, 1-2, 1-3, and 1-4, separators 2-1, 2-2, 2-3, and 2-4, and an input breaker. 3, the grounding wire 4-1, the feeders 4-2, 4-3, and 4-4, the drive unit (hereinafter sometimes referred to as a circuit protector) 6, and the cutoff driven by the drive unit 6. Part 7. The interruption | blocking part 7 has switch 7-1, 7-2, and 7-3. In this example, the protection target device 10 is supplied with power by the power supply lines 4-2 and 4-4 (the power supply line 4-1 is grounded).
In the configuration of the surge protection device according to the present embodiment, for example, for each of the feeder lines 4-4, 4-3, and 4-2, SPD 1-1, 1-2, and 1-3, and a separator (thermal fuse), respectively. Etc.) A circuit in which 2-1, 2-2 and 2-3 and further switches 7-1, 7-2 and 7-3 are connected in series is connected to the ground line 4-1 via the circuit protector 6. . Further, the circuit protector 6 has a series circuit of SPD 1-4 and separator 2-4 in parallel.

  In general, the SPD is mainly classified into a voltage limit type SPD and a voltage switching type SPD. The voltage-limited SPD has a characteristic that the impedance is high when a high voltage is not applied to both ends of the SPD, and the impedance continuously decreases when a high voltage such as a surge voltage is applied and the current flowing through the SPD increases. Examples of the voltage limiting type SPD include a varistor type and a zinc oxide type. The voltage switching type SPD has a high impedance when a high voltage is not applied to both ends of the SPD, and has a characteristic of instantaneously becoming a low impedance when a high voltage such as a surge is applied and the voltage of both ends of the SPD exceeds a certain voltage. Have. Examples of the voltage switching type SPD include an air gap type and a gas discharge tube type. As the SPD 1-1, 1-2, 1-3, and 1-4, in particular, a voltage-limited SPD can be used.

  The separators 2-1, 2-2, 2-3 and 2-4 can use breakers or fuses. The fuse can realize various operating characteristics depending on the element structure, and can achieve both lightning surge resistance and small current interruption performance. Therefore, in this embodiment, the separator 2-1 or 2-2 or 2- It can be assumed that a thermal fuse is used for 3 or 2-4. On the other hand, when a breaker is used for the separator 2-1, 2-2, 2-3, or 2-4, the relationship between the current magnification with respect to the rated current and the breaking time is almost the same regardless of the breaker rating. Therefore, the smaller the rated current, the longer the interruption of the large current due to the short circuit current and the shorter the interruption time of the relatively small current due to the overcurrent. Whether or not cooperation (for example, the input breaker 3 is shut off before the separator 2-1 or 2-2 or 2-3 or 2-4) is determined by the capacity of the input breaker 3. An appropriate breaker may be used as long as a predetermined function for a thermal fuse as will be described later is satisfied.

  The SPDs 1-1, 1-2, and 1-3 installed at the subsequent stage of the input breaker 3 are connected to the feeder lines 4-4, 4-3, and 4-2, respectively, in the normal state. In this state, voltage is applied to 2 and 1-3. If the insulation of the SPD 1-1 or 1-2 or 1-3 deteriorates (SPD deterioration) and a current flows through the SPD 1-1 or 1-2 or 1-3, it is an abnormal phenomenon, and the SPD 1-1 or 1- It is also conceivable that 2 or 1-3 generates heat and becomes hot or bursts. For this reason, in such a case, it is necessary to disconnect the SPD 1-1, 1-2, or 1-3 from the power supply side so that no voltage is applied. The separator 2-1, the separator 2-2, the separator 2-3, or the breaker 7 serves as the circuit breaker.

The circuit protector 6 has a separation coil that generates electromagnetic force. The circuit protector 6 has a rated current of the circuit protector 6 that is lower than that of the input breaker 3 of the protection target device 10 and has an inductance that does not malfunction due to the diversion of lightning surge current. The circuit protector 6 interrupts the interrupter 7 when a fault current occurs. In addition, the circuit protector 6 is further configured to have a contact (switch) that is driven by a disconnecting coil and connected in series with the coil, for example, and disconnects the contact in the same manner as the interrupting unit 7 when a fault current is detected. It is good.
The interruption | blocking part 7 is a switch which can interrupt | block a 3 pole contact, for example in response to the trip signal (electromagnetic force etc.) of the circuit protector 6. Moreover, the interruption | blocking part 7 does not contain a separation coil.

  Note that the means for separating the contacts of the circuit protector 6 and the interrupting section 7 is not limited to means using the electromagnetic force of the separating coil, but may be interrupted by appropriate electric / electronic or mechanical means.

  Further, the connection order of the separators 2-1, 2-2, 2-3, and 2-4 and the SPD 1-1, 1-2, 1-3, and 1-4 may be reversed. Further, a resistor having a large resistance value, a coil having a large inductance, or both may be provided in series with the circuit protector 6 in order to suppress a shunt current from flowing to the circuit protector 6. SPD 1-1, 1-2, 1-3 and 1-4, separators 2-1, 2-2, 2-3 and 2-4, circuit protector 6, and any one or more of blocking sections 7 or The whole structure may be integrated into one unit.

  Further, the number of power supply lines is not limited to the number of examples shown in the figure, and an SPD, a separator, and a switch of a cutoff unit can be appropriately provided for each power supply line according to the number of power supply lines.

2. Operation As described above, in the configuration of the surge protection device according to the present embodiment, the SPD 1-1, 1-2, and 1-3, each having one end connected to each of the feeder lines 4-4, 4-3, and 4-2. A circuit in which a series circuit of SPD 1-4 and a separator (such as a thermal fuse for SPD protection) 2-4 is connected in parallel with the circuit protector 6 is attached between the other end of the circuit and the ground wire 4-1. The circuit protector 6 is provided with a coil for operating the contact of the switch in the same manner as the circuit breaker used for the input breaker 3, and is an element that interrupts the contact with an overcurrent. The circuit protector 6 is characterized by a small rated current, a long interruption time, and various product lineups for the number of contact poles and a small rated current region. The circuit protector 6 has a smaller rated current and a larger coil inductance than the input breaker 3. Therefore, when a lightning surge current flows to SPD1-1, 1-2, or 1-3, the lightning surge current having a high frequency is connected to SPD1-4 and a separator (such as a thermal fuse for SPD protection) 2-4. In the circuit in parallel with the circuit protector 6, most of the circuit flows on the SPD1-4 side, so the circuit protector 6 does not perform a shut-off operation. In addition, the fault current (short-circuit current) that flows due to the fault of SPD 1-1, 1-2, or 1-3 is that SPD 1-4 and a separator (such as a thermal fuse for SPD protection) 2-4 are connected in parallel with circuit protector 6. Since the circuit protector 6 flows through the circuit protector 6 side having a smaller rated current than the input breaker 3, the circuit protector 6 is cut off before the input breaker 3. As a result, when SPD 1-1 or 1-2 or 1-3 fails, SPD 1-1, 1-2 and 1-3 are connected to feeder lines 4-4, 4- without affecting power supply to protection target device 10. 3 and 4-2 can be separated from each other. At this time, in conjunction with the shut-off operation of the circuit protector 6, the shut-off portions that can shut off the contacts are connected to the SPDs 1-1, 1-2, and 1-3 and the feeders 4-4, 4-3, and 4-2. It is possible to block all the SPDs 1-1, 1-2 and 1-3 from the power supply line when one SPD fails. Here, the rated current is defined by, for example, an upper limit current at which the breaker does not break (does not trip). Details of the operation of the circuit protector 6 and the operation coordination between the input breaker 3 and the circuit protector 6 will be described later.

Next, the operation of the surge protection device of the present embodiment will be described in detail with reference to the drawings.
FIG. 2 is an explanatory diagram showing a lightning surge current flow when a lightning surge enters the normal state in the surge protection device of the present embodiment.
In the figure, an arrow indicates a current (lightning surge current) that flows when a lightning surge enters the feeder line. For example, in the power supply line 4-4, the lightning surge current flows to the ground line 4-1 through the switch 7-1 and the separator 2-1, through the SPD 1-1. At this time, in the circuit in which the SPD 1-4 and the separator (thermal fuse for SPD protection, etc.) 2-4 are arranged in parallel with the circuit protector 6, the circuit protector 6 side has a large internal inductance and a high-frequency current hardly flows. Most of the lightning surge current flows through the SPD 1-4 and the separator 2-4 to the ground line 4-1. For this reason, the lightning surge current can be normally released to the ground. Thereby, in the surge protection apparatus of this Embodiment, the protection object apparatus 10 can be protected from a lightning surge. Similarly, when a lightning surge enters the feeder line 4-2 or 4-3, most of the lightning surge current flows to the ground line 4-1 through the SPD 1-4 and the separator 2-4. You can escape to the ground normally.
In addition, if the circuit protector 6 malfunctions due to a lightning surge current that is diverted to the circuit protector 6, it is possible to reduce the diverted current by inserting a coil or a resistor having a large inductance in series with the circuit protector 6. Is possible.

FIG. 3 is an explanatory diagram showing the flow of a failure (short circuit) current when an SPD failure occurs in the surge protection device of the present embodiment.
In this figure, as an example, an arrow indicates a failure (short circuit) current passing through the SPD 1-1 when the SPD 1-1 fails. Since the voltage applied to the failed SPD 1-1 is a commercial power supply voltage, and the other three normal SPDs 1-2, 1-3, and 1-4 have high resistance, no current flows. Flows through the circuit protector 6 side to 1. Therefore, the circuit protector 6 is a blocking unit 7 having a function of performing a blocking operation in conjunction with the circuit protector 6 by detecting a failure current flowing in the SPD 1-1, 1-2, or 1-3 (detecting a failure). 1, 1-2 and 1-3 and the feeder lines 4-4, 4-3 and 4-2 are blocked. At this time, the circuit protector 6 is cut off before the input breaker 3 because the rated current is smaller than that of the input breaker 3. Similarly, when the circuit protector 6 has a contact, the contact can be separated by electromagnetic force generated by the internal coil.
As a result, the surge protection device according to the present embodiment feeds the SPD 1-1, 1-2, and 1-3 without affecting the power supply to the protection target device 10 regardless of the SPD failure status (resistance value). It can block from 4-4, 4-3 and 4-2. In addition, the switch 7 between the SPD 1-1, 1-2, and 1-3 and the feeder lines 4-4, 4-3, and 4-2 is disconnected, and a switch with a small inductance is used. It is possible to reduce the overvoltage generated in the section 7.

3. Characteristics (1) Motion coordination (protection coordination)
FIG. 4 is an explanatory diagram of operation cooperation between the input breaker and the circuit protector.
In general, the circuit protector 6 and the input breaker 3 are similar in the relationship (characteristics) between the magnification against the rated current and the cutoff time (characteristics). Smaller ones operate faster even when the fault current is small or large. That is, since the breaker of the large current and the small current is longer as the rated current is larger, the breaker with the lower rated current operates faster than the higher breaker. In this embodiment, the circuit protector 6 is the input breaker. Select one with a rated current lower than 3. Thereby, the circuit protector 6 can be shut off earlier than the input breaker 3 (operation coordination, protection coordination).

(2) Thermal fuse For example, when a thermal fuse is used as the separator 2-1 and / or 2-2 and / or 2-3, the thermal fuse for the separator must not be blown even if a lightning surge current flows. First, the SPD 1-1 or 1-2 or 1-3 is deteriorated, and a function of cutting off the electric circuit is required only when a leakage current flows with a normal AC power supply voltage (commercial power supply voltage). That is, the thermal fuse has the following functions.
-When SPD1-1 or 1-2 or 1-3 is normal, it will not be cut even if a lightning surge current flows. Note that when the SPD 1-1 or 1-2 or 1-3 fails, the interrupting unit 7 is already interrupted by a certain amount of current (failure current) as described above. For this reason, no lightning surge current flows through the system in which the SPD has failed.
When the thermal fuse (separator 2-1 or 2-2 or 2-3) is blown, for example, the SPD 1-1 or 1-2 or 1-3 deteriorates and the SPD 1-1 or 1-2 or 1 -3 insulation is reduced, leakage current flows from SPD 1-1, 1-2, or 1-3, and the circuit protector 6 does not operate (the interrupting section 7 cannot be cut off). For example, the case where the leakage current below the rated current of the circuit protector 6 is flowing, etc. are mentioned.

(3) Interrupting characteristic FIG. 5 shows an explanatory diagram of the interrupting characteristic.
In general, the unlatching time refers to a maximum overcurrent energization time that does not lead to an operation when a certain overcurrent flows for a certain time NFB (No Fuse Breaker). In order to ensure the operation coordination between the input breaker 3 and the circuit protector 6, the unlatching time of the input breaker 3 may be further increased so as not to cross the operation characteristic curve of the circuit protector 6. For example, a no-fuse breaker (NFB) having a short-time tripping characteristic, an electronic NFB that can be adjusted as such, and the like can be used.

  The present invention can be applied to, for example, various systems in which the ground on the power supply side and the ground of the target device are provided as the same.

The block diagram of the surge protective device by this Embodiment. In the surge protective device of this form, it is explanatory drawing about the flow of the lightning surge current when the lightning surge invades normally. In the surge protective device of this Embodiment, explanatory drawing about the flow of the short circuit current at the time of SPD failure. Explanatory drawing of operation | movement cooperation of an input breaker and a circuit protector. Explanatory drawing about the interruption | blocking characteristic. The block diagram of the conventional surge protection apparatus in a three-wire-type electric power feeding system (TN type).

Explanation of symbols

1-1, 1-2, 1-3, 1-4 SPD
2-1, 2-2, 2-3, 2-4 Separator 3 Input breaker 4-1 Ground line 4-2, 4-3, 4-4 Feed line 6 Circuit protector (drive unit)
7 Blocking unit 7-1, 7-2, 7-3 Switch 10 Device to be protected 17 SPD separator

Claims (15)

An ungrounded first power supply line for supplying electricity to the protection target device on the protection target device side;
A grounding wire that is grounded on the power supply side and supplied to the device to be protected;
An ungrounded second feeder on the power supply side;
An input breaker provided between the ungrounded first power supply line and the second power supply line, for connecting or disconnecting the first power supply line and the second power supply line;
A first switch, a first separator, a first surge protection device, and a second surge protection device provided in series between the first power supply line and the ground line on the protection target device side And a second separator;
A drive unit that is provided in parallel with a series circuit of the second surge protection device and the second separator, and operates to shut off the shut-off unit;
With
Upon failure of the first surge protection device, a short-circuit current passing through the first surge protection device is transferred from the first feeder to the first switch of the interrupting unit, the first separator, the first 1 surge protection device, a surge that is caused to flow to the ground line through the drive unit, so that the drive unit drives the first switch of the blocking unit and disconnects it before the input breaker. Protective device.
A lightning surge from the first power supply line is transmitted to the first switch of the interrupter, the first separator, the first surge protection device, the second surge protection device, and the second The surge protection device according to claim 1, wherein the surge protection device is caused to flow to the grounding wire via a separator.
The surge protection device according to claim 1 or 2, wherein the first and second surge protection devices are voltage-limited surge protection devices.
An ungrounded third feeder on the protected device side;
A non-grounded fourth feeder on the power supply side that is connected or disconnected from the third feeder by the input breaker;
A second switch, a third separator, and a third surge protection device provided between the third power supply line and the ground line on the protection target device side;
Further comprising
2. The device according to claim 1, wherein when the third surge protection device fails, the driving unit drives the first and second switches of the shut-off unit to disconnect them before the input breaker. The surge protection apparatus in any one of thru | or 3.
The surge protection device according to any one of claims 1 to 4, wherein the surge protection device is used in a single-point grounding TN power supply system.
6. The drive unit according to claim 1, wherein a rated current is lower than that of the input breaker of the device to be protected, and has an inductance large enough to prevent malfunction due to a diversion of lightning surge current. The surge protection device according to any one of the above.
The surge protection device according to any one of claims 1 to 6, wherein the configuration of the blocking unit and the driving unit and the input breaker have a short time tripping characteristic.
In the operation characteristic representing the relationship between the interruption time and the current, the interruption time of the interruption part and the drive part is at least the input breaker in the long time trip region and / or the short time trip region less than the instantaneous trip current. The surge protection device according to any one of claims 1 to 7, wherein the surge protection device is shorter than the shut-off time.
In the operating characteristics representing the relationship between the breaking time and the current, the breaking time in the instantaneous tripping region of the configuration by the breaking unit and the driving unit is made shorter than the unlashing time in the instantaneous tripping region of the input breaker. The surge protection device according to any one of claims 1 to 8, wherein an unlashing time of the input breaker is not crossed with an operating characteristic of the configuration of the blocking unit and the driving unit.
A resistor provided in series with the drive unit and having a sufficiently large resistance value, a coil having a sufficiently large inductance, or both of the resistor and the inductance, in order to suppress a diversion of lightning surge current to the drive unit The surge protection device according to any one of claims 1 to 9, further comprising:
The surge protection device according to any one of claims 1 to 10, wherein the drive unit is further provided with a switch that is provided in series with an internal coil and is operated to be cut off by the coil.
The surge protection device according to any one of claims 1 to 11, wherein the configuration of the blocking unit and the driving unit and the input breaker are an electromagnetic no-fuse breaker or an electronic no-fuse breaker.
The surge protection device according to any one of claims 1 to 12, wherein the first and second separators are thermal fuses.
The thermal fuse has a current region smaller than a rated current of the first and second surge protection devices, and generates heat due to a leakage current of the first and second surge protection devices, and the first and second surge protections. The surge protection device according to claim 13, wherein the device is configured to be disconnected from the circuit.
A structure in which at least one or all of the interrupting unit, the first and second separators, the first and second surge protection devices, and the driving unit are integrated into one unit. The surge protection device according to claim 1, comprising:

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