Surge protection element status check device

Abstract

To provide a state determination device capable of determining whether a target is normal or failed, the target being an SPD that is applicable to various power supply systems.SOLUTION: An SPD 10A includes: first to third power source terminals T1 to T3 that can be connected respectively to power source lines of three phases; first to third series circuits formed of first to third overcurrent separators F1 to F3 and first to third heat separators TD1 to TD3 that are connected in series to a path extending from the power source terminals to a grounded terminal E; first voltage detection means 11 that detects a voltage V1; second voltage detection means 12 that detects a voltage V2; and third voltage detection means 13 that detects a voltage V3 between the power source terminals T2 and T3 or between the power source terminals T1 and T3. It is determined whether the SPD 10A is normal or failed on the basis of the presence / absence of the second voltage V2 and the first voltage V1 that are not equal to 0 [V] when the voltage V3 not equal to 0 [V] is detected, and meanwhile, on the basis of the presence / absence of the voltage V1 when the voltage V3 is equal to 0 [V].SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a status checking device for checking whether a surge protection device (hereinafter also referred to as SPD) is normal or faulty. [Background Art]

[0002] Generally, an SPD has a function of indicating its status when a built-in overcurrent disconnecting device or thermal disconnecting device operates, and outputting an alarm contact signal as required. Here, Fig. 2 is a diagram illustrating the status indication and alarm contact operation of an SPD 10 together with the circuit configuration of the SPD 10, in a case where a device to be protected (not shown) protected by the SPD 10 is connected to a power system of a three-wire type (such as single-phase three-wire 100 / 200 V, three-phase three-wire 200 V, three-phase three-wire 415 V) or a four-wire type (such as three-phase four-wire 100 / 200 V, three-phase four-wire 240 / 415 V).

[0003] In Fig. 2, L1, L2 and L3 are power lines of the power system, and LN is a neutral line. When the power system is of three-wire type, the SPD 10 is connected between the power lines L1, L2, L3 and a ground terminal E; when the power system is of four-wire type, the SPD 10 is connected between the power lines L1, L2, L3, the neutral line LN, and the ground terminal E.

[0004] The SPD 10 comprises overcurrent disconnecting devices F1, F2, F3 such as current fuses, thermal disconnecting devices TD1, TD2, TD3, metal oxide varistors MOV1, MOV2, MOV3, and a gas-filled discharge tube GDT connected as required. For the power lines L1, L2, L3 of respective phases, the overcurrent disconnecting device F1, the thermal disconnecting device TD1 and the metal oxide varistor MOV1; the overcurrent disconnecting device F2, the thermal disconnecting device TD2 and the metal oxide varistor MOV2; and the overcurrent disconnecting device F3, the thermal disconnecting device TD3 and the metal oxide varistor MOV3 are each integrally formed.

[0005] The protection circuit, consisting of heat separators TD1, TD2, TD3 and overcurrent separators F1, F2, F3, functions to disconnect metal oxide varistors MOV1, MOV2, MOV3 from the circuit due to increased leakage current caused by aging degradation of the metal oxide varistors MOV1, MOV2, MOV3, repeated application of lightning surges, overvoltage, etc., or due to short-circuit current after the metal oxide varistors MOV1, MOV2, MOV3 are destroyed in short-circuit mode. In other words, in response to the heat generated as described above, the low-melting-point alloys in the heat separators TD1, TD2, and TD3 melt to interrupt the circuit, and in response to the short-circuit current, the overcurrent separators F1, F2, and F3 operate to interrupt the circuit.

[0006] On the other hand, since the SPD10 needs to perform its primary function of protecting the protected equipment from lightning surges, it is desirable that it constantly monitors the status of the aforementioned overcurrent separators F1, F2, F3 and heat separators TD1, TD2, TD3, etc., and displays their status (indicating normal or faulty). In the event of a failure of the SPD10, it should output an alarm to an external circuit by activating an alarm contact.

[0007] Therefore, conventionally, status display and alarm contact operation are performed according to the flowchart in Figure 2. In other words, when the SPD10 is used in connection with a three-phase three-wire or three-phase four-wire power supply system, as shown in Figure 2, the voltage V1 between the connection point of the heat separator TD1 and the metal oxide varistor MOV1, and the connection point of the heat separator TD2 and the metal oxide varistor MOV2 is detected by the voltage detection means 11, and the voltage V2 between the connection point of the heat separator TD2 and the metal oxide varistor MOV2, and the connection point of the heat separator TD3 and the metal oxide varistor MOV3 is detected by the voltage detection means 12. Here, the voltage detection means 11 and 12 are not particularly limited in principle, type of element, or circuit configuration as long as they can convert the presence or absence of voltage into the presence or absence of an electrical signal or optical signal. For example, LEDs, relays, photocouplers, photoMOSs, transistors, transformers, etc., can be used. Alternatively, instead of voltage V2, the voltage V3 between the connection point of the heat separator TD1 and the metal oxide varistor MOV1, and the connection point of the heat separator TD3 and the metal oxide varistor MOV3 may be detected and used. However, the decision-making process in that case is the same as described below, so the explanation is omitted.

[0008] Based on the voltages V1 and V2 described above, for example, if voltage V2 is present (a voltage other than 0[V] is detected, and the same applies hereinafter) and voltage V1 is also present (step S1 Yes, step S2 Yes), then none of the overcurrent separators F1, F2, F3 or the heat separators TD1, TD2, TD3 are open-circuit faults, and SPD10 can be determined to be normal. For this reason, the status indicator is lit (step S3), and if there is an alarm contact function, the alarm contact is deactivated (step S4).

[0009] Furthermore, if there is no voltage V2 (step S1No), i.e. (when 0[V] is detected, and the same applies hereafter), or if there is voltage V2 but no voltage V1 (step S1Yes, step S2No), then one of the overcurrent separators F1, F2, F3 or the heat separators TD1, TD2, TD3 is open-circuited and SPD10 is judged to be faulty (abnormal). Therefore, the status indicator is turned off (step S5), and if there is an alarm contact function, it is activated to output an alarm to the external circuit (step S6).

[0010] In this case, when the SPD10 shown in Figure 2 is applied to a single-phase two-wire power supply system, power terminals T1 and T2 are connected to power lines L1 and L2 respectively, but power terminal T3 and the neutral wire terminal TN are left open. However, if connected as described above, even if SPD10 is functioning correctly, the voltage V2 will be absent (step S1No), causing SPD10 to be judged as faulty, resulting in the status indicator turning off (step S5) and the alarm contact activating (step S6).

[0011] To prevent such misjudgments, it is necessary to short-circuit the power terminals T1 and T3 (or power terminals T2 and T3), which is a cumbersome process for the user, and in some cases, the short-circuiting process may be forgotten before use.

[0012] Prior art related to SPD status display is known, for example, as described in Patent Documents 1 to 3. However, the SPDs described in Patent Documents 1 and 2 are based on the premise of connection to a single-phase three-wire power supply system, and the SPD described in Patent Document 3 is based on the premise of connection to a single-phase two-wire power supply system or communication system. In other words, there was a problem that a single SPD or its status or fault detection device could not handle situations where the equipment to be protected by the SPD was compatible with various power supply systems such as single-phase two-wire or three-wire, or three-phase three-wire or four-wire. [Prior art documents] [Patent Documents]

[0013] [Patent Document 1] Patent No. 5014742 [Patent Document 2] Patent No. 5629222 [Patent Document 3] Patent No. 6307381 [Overview of the project] [Problems that the invention aims to solve]

[0014] Therefore, the problem to be solved by the present invention is to provide a status confirmation device that allows for easy confirmation of the normal or faulty status of surge protection elements applicable to various power supply systems such as single-phase two-wire or three-wire, and three-phase three-wire or four-wire systems, using a single circuit configuration. [Means for solving the problem]

[0015] To solve the above problems, the present invention provides a status confirmation device for confirming whether surge protection elements connected to each phase power line of a power system are functioning normally or have malfunctions, The surge protection element is, First, second, and third power terminals that can be connected to each phase power line of a three-phase power system, A first series circuit consisting of a first overcurrent separator and a first heat separator connected in series in a path from a first power terminal to a ground terminal, A second series circuit comprising a second overcurrent separator and a second heat separator connected in series in a path from the second power terminal to the ground terminal, A third series circuit comprising a third overcurrent separator and a third heat separator connected in series in a path from the third power terminal to the ground terminal, A first voltage detection means for detecting the voltage between the ground terminal end of the first series circuit and the ground terminal end of the second series circuit, A second voltage detection means for detecting the voltage between the ground terminal end of the second series circuit and the ground terminal end of the third series circuit, A third voltage detection means for detecting the voltage between the second power terminal and the third power terminal, or between the first power terminal and the third power terminal, Equipped with, When the third voltage detection means detects a third voltage other than 0[V], The surge protection element is deemed to be functioning normally or malfunctioning based on whether a second voltage other than 0[V] and a first voltage are detected, respectively, by the second voltage detection means and the first voltage detection means.

[0016] Furthermore, the present invention relates to the surge protection element status confirmation device described in claim 1, When the third voltage detection means detects a third voltage other than 0[V], When a second voltage other than 0[V] is detected by said second voltage detecting means, and a first voltage other than 0[V] is detected by said first voltage detecting means, said surge protection element is determined to be normal; and when a second voltage other than 0[V] is detected by said second voltage detecting means, and 0[V] is detected as the first voltage by said first voltage detecting means, said surge protection element is determined to be faulty.

[0017] Further, the present invention provides the status check device for a surge protection element according to claim 1 or 2, wherein When 0[V] is detected as a third voltage by said third voltage detecting means, and a first voltage other than 0[V] is detected by said first voltage detecting means, said surge protection element is determined to be normal; and when 0[V] is detected as the first voltage by said first voltage detecting means, said surge protection element is determined to be faulty.

[0018] Furthermore, the present invention provides the status check device for a surge protection element according to claim 1, wherein Between the end portion of said first thermal disconnector on the ground terminal side and said connec ground edge tor, a first metal oxide varistor and a gas-filled discharge tube are connected in series, Between the end portion of said second thermal disconnector on the ground terminal side and said connec ground edge tor, a second metal oxide varistor and said gas-filled discharge tube are connected in series, Between the end portion of said third thermal disconnector on the ground terminal side and said connec ground edge tor, a third metal oxide varistor and said gas-filled discharge tube are connected in series, which is also a possible configuration.

Effects of the Invention

[0019] According to the present invention, for various power supply systems such as single-phase two-wire, single-phase three-wire, three-phase three-wire, or three-phase four-wire systems, the normality or fault of an SPD can be checked by a status check device having a single circuit configuration added to the SPD, and complicated work such as short-circuiting between power supply terminals when applying the SPD to a single-phase two-wire power supply system can be avoided. [Brief explanation of the drawing]

[0020] [Figure 1] This figure shows the status display and alarm contact operation of an SPD according to an embodiment of the present invention, along with the circuit configuration. [Figure 2] This diagram shows the status display and alarm contact operation of a conventional SPD (Speed ​​Disposal Device) along with its circuit configuration. [Modes for carrying out the invention]

[0021] Embodiments of the present invention will be described below with reference to the figures. In Figure 1, the same reference numerals are used for parts that are identical to those in Figure 2. The following explanation will focus on the differences between Figure 1 and Figure 2.

[0022] In Figure 1, in addition to the components shown in Figure 2, the SPD10A is equipped with a voltage detection means 13 on the power supply side of the overcurrent separators F2 and F3 that detects the voltage V3 between the power supply terminals T2 and T3. This voltage detection means 13 can be an LED, relay, photocoupler, photoMOS, transistor, transformer, etc., similar to the voltage detection means 11 and 12.

[0023] The voltage detection means 13 may also be connected to detect the voltage between power supply terminals T1 and T3. Alternatively, the portion excluding the overcurrent separators F1, F2, and F3 may be configured as an SPD, and the overcurrent separators F1, F2, and F3 may be connected outside the SPD between the power lines L1, L2, and L3 and the power terminals T1, T2, and T3, respectively. Furthermore, the gas-filled discharge tube (GDT) is not essential; the common connection point of the metal oxide varistors MOV1, MOV2, and MOV3 can be directly connected to the ground terminal E.

[0024] In the configuration described above, the status display and alarm contact operation of the SPD10A are as follows: For example, when using the SPD10A in a three-phase three-wire power system, connect power terminals T1, T2, and T3 to power lines L1, L2, and L3 in Figure 2, respectively. When using it in a three-phase four-wire power system, in addition to the above, connect the neutral wire terminal TN to the neutral wire LN.

[0025] In this embodiment, in addition to the voltage V1 detected by the voltage detection means 11 and the voltage V2 detected by the voltage detection means 12, the presence or absence of the voltage V3 between power terminals T2 and T3 detected by the voltage detection means 13 is also included in the determination of the status display of the SPD10A. Then, if there is no voltage V3 (voltage V3 is 0[V]) (step S0No in Figure 1), the process proceeds to step S2 without determining the presence or absence of voltage V2, and the presence or absence of voltage V1 is determined. The processing from step S2 onward is the same as in the conventional Figure 2, and the presence or absence of a fault in SPD10A (the status indicator is lit or off) is determined according to the presence or absence of voltage V1.

[0026] When the SPD10A is connected to a power supply system, for example, a three-phase three-wire or three-phase four-wire system, the voltage detection means 13 detects a voltage V3 other than 0[VV], so in step S0, the branch is routed to Yes. Therefore, the same processing as in Figure 2 is performed thereafter depending on the presence or absence of voltages V2 and V1, and the status display and alarm contact operation of the SPD10A are performed.

[0027] In contrast, when applying the SPD10A to a single-phase two-wire power system, for example, power terminals T1 and T2 are connected to power lines L1 and L2 respectively, while power terminal T3 and the neutral wire terminal TN are left open. As a result, voltage V3 becomes zero (0[V]), so in step S0, the branch is to No and the process moves to the decision in step S2.

[0028] If a voltage V1 other than 0[V] exists in this state (step S2 Yes), then none of the overcurrent separators F1, F2 or the heat separators TD1, TD2 are open-circuit faults, and as long as it is applied to a single-phase two-wire power supply system, the SPD10 can be judged to be normal. Accordingly, the status indicator to that effect is lit (step S3), and if there is an alarm contact function, the alarm contact is deactivated (step S4).

[0029] Furthermore, if the voltage V1 is none, i.e., 0[V] (step S2No), then either the overcurrent separators F1, F2 or the heat separators TD1, TD2 have an open circuit failure, and as long as it is applied to a single-phase two-wire power supply system, the SPD10 can be judged as faulty (abnormal). Accordingly, the status indicator is turned off (step S5), and if there is an alarm contact function, the alarm contact is activated to output an alarm to the external circuit (step S6).

[0030] As described above, even when the SPD10A is applied to a single-phase two-wire power supply system in this embodiment, the trouble of short-circuiting the power terminals T2 and T3 (or power terminals T1 and T3) as in the conventional method is eliminated, thus reducing the work involved in checking the status of the SPD10A.

[0031] In the embodiment shown in Figure 1, there is a risk that the SPD status display and alarm contact operation may malfunction during a power outage. However, by using, for example, the false detection prevention technology during power outages disclosed in Patent No. 7103727 by the present inventor, it is possible to prevent malfunctions in the SPD status display and alarm contact operation. [Explanation of Symbols]

[0032] 10,10A: SPD (Surge Protection Device) 11, 12, 13: Voltage detection means L1,L2,L3: Power line LN: Neutral wire T1, T2, T3: Power terminals TN: Neutral wire terminal E: Ground terminal F1,F2,F3: Overcurrent separator TD1,TD2,TD3:Thermal separator MOV1, MOV2, MOV3: Metal oxide varistors GDT: Gas-filled discharge tube

Claims

1. A status confirmation device for checking whether surge protection elements connected to each phase power line of a power system are functioning correctly or are malfunctioning, The surge protection element is, First, second, and third power terminals that can be connected to each phase power line of a three-phase power system, A first series circuit consisting of a first overcurrent separator and a first heat separator connected in series in a path from a first power terminal to a ground terminal, A second series circuit comprising a second overcurrent separator and a second heat separator connected in series in a path from the second power terminal to the ground terminal, A third series circuit comprising a third overcurrent separator and a third heat separator connected in series in a path from the third power terminal to the ground terminal, A first voltage detection means for detecting the voltage between the ground terminal end of the first series circuit and the ground terminal end of the second series circuit, A second voltage detection means for detecting the voltage between the ground terminal end of the second series circuit and the ground terminal end of the third series circuit, A third voltage detection means for detecting the voltage between the second power terminal and the third power terminal, or between the first power terminal and the third power terminal, Equipped with, When the third voltage detection means detects a third voltage other than 0 [V], A surge protection element status confirmation device characterized by determining whether the surge protection element is normal or malfunctioning based on whether a second voltage other than 0 [V] and a first voltage are detected, respectively, by the second voltage detection means and the first voltage detection means.

2. In the surge protection element status confirmation device described in claim 1, When the third voltage detection means detects a third voltage other than 0 [V], When the second voltage detection means detects a second voltage other than 0 [V], and the first voltage detection means detects a first voltage other than 0 [V], the surge protection element is judged to be normal, and when the second voltage detection means detects a second voltage other than 0 [V], and the first voltage detection means detects 0 [V] as the first voltage, A surge protection element status confirmation device characterized by determining that the surge protection element is malfunctioning.

3. In the surge protection element status confirmation device described in claim 1 or 2, The third voltage detection means detects 0 [V] as the third voltage, and, A surge protection element status confirmation device characterized in that it determines the surge protection element is normal when a first voltage other than 0 [V] is detected by the first voltage detection means, and determines the surge protection element is faulty when 0 [V] is detected as the first voltage by the first voltage detection means.

4. In the surge protection element status confirmation device described in claim 1, A first metal oxide varistor and a gas-filled discharge tube are connected in series between the end of the first heat separator on the grounding terminal side and the grounding terminal. The second metal oxide varistor and the gas-filled discharge tube are connected in series between the end of the second heat separator on the grounding terminal side and the grounding terminal. A surge protection element status confirmation device characterized in that a third metal oxide varistor and the gas-filled discharge tube are connected in series between the end of the third heat separator on the grounding terminal side and the grounding terminal.

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