JP2017134935A - Deterioration diagnosis device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To determine deterioration of a zinc oxide element with simple means, for an arrestor of sealed structure where a principal section, consisting of a series connection of the zinc oxide element and a discharge gap, is coated with an insulation enclosure.SOLUTION: A deterioration diagnosis device 17 for applying a test voltage to an arrestor 11 where the principal section, consisting of a series connection of a zinc oxide element 12 and a discharge gap 13, is coated with an insulation enclosure 14, and determining deterioration state of the arrestor 11 based on the voltage characteristics of the arrestor 11 when the test voltage is increased, is constituted of a voltage supply unit 18 for applying the test voltage to the arrestor 11, and stopping application of the test voltage at a moment in time when the discharge start voltage of the discharge gap 13 is reached by increasing the test voltage, a voltage measurement unit 20 for measuring the voltage in a specified time range of the residual voltage obvious immediately after test voltage application stop, and a determination unit 21 for determining deterioration of the zinc oxide element 12 based on the measured value of the residual voltage.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a deterioration diagnosis apparatus that determines a deterioration state of a lightning arrester that is a type of lightning protection equipment installed on a distribution line.

  For example, when an abnormal voltage occurs due to lightning strikes on or near the high-voltage distribution line, as a lightning protection device to protect various electrical devices connected to the high-voltage distribution line from lightning surge, It is common to install a lightning arrester between the ground and the ground side.

  This type of lightning arrester is a device to limit the instantaneous overvoltage caused by direct lightning or induced lightning and to discharge surge current to the ground, connecting a zinc oxide element (ZnO element) and a discharge gap in series. Is covered with an insulating jacket such as an insulator and sealed with a metal lid.

  In the lightning arrester having such a structure, it is deteriorated by repeatedly applying a surge voltage, and finally, it is not an insulation resistor, and a failure state in which a current always flows is reached. When such a lightning arrester goes into a failure state, the metal lid swells, so the lightning arrester is visually observed from the outside, or the insulation resistance of the lightning arrester is low, so by measuring the insulation resistance, The failure of the lightning arrester is judged.

  In addition, by applying a DC voltage to the lightning arrester, the discharge start voltage of the discharge gap, which is one of the components of the lightning arrester, is measured to determine whether the lightning arrester has deteriorated or failed (for example, Patent Literature 1). That is, if the measured value of the discharge start voltage is lower than the reference value, the discharge gap is degraded, and if the measured value of the discharge start voltage is 0, it means that there is a failure.

JP 2013-131391 A

  By the way, in the lightning arrester inspection, as described above, the lightning arrester failure is determined by visually observing the lightning arrester from the outside or by measuring the insulation resistance of the lightning arrester. However, in a deteriorated state until the lightning arrester reaches a failure state, the metal lid does not bulge, and since the discharge gap is connected in series with the zinc oxide element, it is possible to directly measure the insulation resistance of the zinc oxide element. Since it is not possible to detect a decrease in insulation resistance, it is not possible to determine the deterioration of the lightning arrester.

  On the other hand, in Patent Document 1 described above, the deterioration of the lightning arrester is determined by applying a DC voltage to the lightning arrester and measuring the discharge start voltage of the discharge gap. However, the deterioration of the lightning arrester is caused by a discharge gap that is one of the components of the lightning arrester. Zinc oxide elements, which are other components of the lightning arrester, tend to deteriorate more than the discharge gap. Conventionally, regarding a lightning arrester in which a main part in which a zinc oxide element and a discharge gap are connected in series is covered with an insulating jacket, it is impossible to determine the deterioration of a zinc oxide element that may deteriorate earlier than the discharge gap. That was the current situation.

  As described above, a lightning arrester that is an object of deterioration determination includes a sealed structure in which a main part in which a zinc oxide element and a discharge gap are connected in series is covered with an insulating jacket. Therefore, even when the discharge start voltage of the discharge gap can be measured by taking out the voltage between both terminals of the lightning arrester side and the ground side terminal as in the case of determining the deterioration of the discharge gap, In order to determine the deterioration of only the element, the voltage across the zinc oxide element cannot be taken out.

  Therefore, the present invention has been proposed in view of the above-mentioned problems, and the object of the present invention is a sealed structure in which a main part in which a zinc oxide element and a discharge gap are connected in series is covered with an insulating jacket. An object of the present invention is to provide a deterioration diagnosis device capable of determining deterioration of a zinc oxide element with a simple means in a lightning arrester.

  As a technical means for achieving the above-mentioned object, the present invention applies a test voltage to a lightning proof device in which a main part in which a zinc oxide element and a discharge gap are connected in series is covered with an insulation jacket, and the test is performed. A deterioration diagnosis device that determines the deterioration state of lightning-resistant equipment based on the voltage characteristics of lightning-proof equipment when the voltage is increased, and applies a test voltage to the lightning-proof equipment and increases the test voltage to discharge the discharge gap. A voltage supply unit that stops the application of the test voltage when the start voltage is reached, a voltage measurement unit that measures the voltage in the specified time range of the residual voltage that has become apparent immediately after the application of the test voltage is stopped, and a measured value of the residual voltage And a determination unit for determining the deterioration state of the zinc oxide element based on the above.

  In the present invention, the voltage supply unit applies a test voltage to the lightning protection device, increases the test voltage, and stops applying the test voltage when the discharge start voltage of the discharge gap is reached. After this gap discharge, the voltage of the lightning protection device decreases due to the stop of the application of the test voltage, but the residual voltage corresponding to the characteristics of the zinc oxide element becomes obvious. The voltage measurement unit measures the voltage in the specified time range of the residual voltage that becomes apparent immediately after the application of the test voltage is stopped.

  The determination unit determines the deterioration state of the zinc oxide element based on the measured value of the residual voltage. In other words, the residual voltage in the specified time range for a defective product with a deteriorated zinc oxide element is lower than the residual voltage in the specified time range for a good product with no deteriorated zinc oxide element. If the residual voltage is too low, it can be determined that the zinc oxide element has deteriorated.

  The determination unit in the present invention is preferably configured to determine the deterioration state of the discharge gap based on the measured value of the discharge start voltage of the discharge gap. By adopting such a configuration, it is possible to determine the deterioration state of the discharge gap in addition to determining the deterioration of the zinc oxide element. Thereby, it is possible to improve reliability in determining deterioration of lightning-resistant equipment.

  According to the present invention, the test voltage is applied to the lightning protection equipment, and the test voltage is increased to stop the application of the test voltage when the discharge start voltage of the discharge gap is reached, and the test voltage application is stopped. By comprising a voltage measuring unit that measures voltage in the specified time range of the residual voltage that has become apparent immediately after and a determination unit that determines the deterioration state of the zinc oxide element based on the measured value of the residual voltage, the zinc oxide element The degradation of the zinc oxide element can be determined by a simple means even for a lightning-resistant device having a sealed structure in which a main part in which a discharge gap is connected in series is covered with an insulating jacket. As a result, the deterioration of the zinc oxide element can be accurately grasped, and the reliability can be improved in determining the deterioration of the lightning resistant equipment.

In an embodiment of the present invention, it is a block diagram showing a schematic structure of a degradation diagnostic device. It is an operation | movement flowchart which shows the point which determines deterioration of a discharge gap. It is an operation | movement flowchart which shows the point which determines degradation of a zinc oxide element. It is a wave form diagram which shows the output characteristic of the lightning arrester connected to the degradation diagnostic apparatus of FIG. It is a wave form diagram which shows the output characteristic of the lightning arrester which expanded the A section of FIG.

  Embodiments of the deterioration diagnosis apparatus according to the present invention will be described in detail below. In the following embodiments, a lightning arrester, which is a kind of lightning protection equipment installed on a distribution line, is exemplified as an object of deterioration determination by the deterioration diagnosis device. In addition, this invention is not limited to this, It is applicable also to lightning-resistant equipment other than a lightning arrester.

  As shown in FIG. 1, the lightning arrester 11 has a sealed structure in which a main part in which a zinc oxide element 12 (ZnO element), which is a lightning protection element, and a discharge gap 13 are connected in series is covered with an insulating envelope 14 such as an insulator. It has. The lightning arrester 11 has a power transmission side terminal 15 connected to the distribution line and a ground side terminal 16 connected to the ground.

  The deterioration diagnosis device 17 of this embodiment is connected between the power application side terminal 15 and the ground side terminal 16 of the lightning arrester 11 described above. The deterioration diagnosis device 17 has a function of determining deterioration of the discharge gap 13 and a function of determining deterioration of the zinc oxide element 12.

  As shown in FIG. 1, the deterioration diagnosis device 17 applies a DC test voltage between the power application side terminal 15 and the ground side terminal 16 of the lightning arrester 11 and increases the test voltage to discharge the discharge gap 13. When the start voltage is reached, the voltage supply unit 18 stops applying the test voltage, and the mode of the voltage supply unit 18 is switched between when the deterioration of the discharge gap 13 is determined and when the deterioration of the zinc oxide element 12 is determined. A switching unit 19, a voltage measuring unit 20 that measures a discharge start voltage of the discharge gap 13 by applying a test voltage, and measures a voltage within a specified time range of a residual voltage that is manifested immediately after the application of the test voltage is stopped; The determination unit 21 includes a determination unit 21 that determines the deterioration state of the discharge gap 13 based on the measurement value of the starting voltage and determines the deterioration state of the zinc oxide element 12 based on the measurement value of the residual voltage.

  The switching unit 19 in this deterioration diagnosis apparatus can be configured with either a mechanical switch or a semiconductor switch. In addition, the voltage supply unit 18, the voltage measurement unit 20, and the determination unit 21 can be constructed with a circuit configuration including a CPU, either hardware or software. Furthermore, although not shown, the determination unit 21 is provided with a lamp or buzzer for displaying the result of deterioration determination.

  Before describing the characteristic configuration of this embodiment, the point of determining the deterioration state of the discharge gap 13 by the above-described deterioration diagnosis device 17 will be described in detail below with reference to FIG.

  First, the switching unit 19 sets a mode for determining the deterioration state of the discharge gap 13 (STEP 1). In this mode, the voltage supply unit 18 applies a DC test voltage between the power application side terminal 15 and the ground side terminal 16 of the lightning arrester 11. Application of the test voltage in this mode gradually increases the test voltage at a rate of, for example, about 1 kV / s (STEP 2). As described above, by gradually increasing the test voltage, variations in the discharge start voltage of the discharge gap 13 are suppressed.

  When the test voltage is increased to reach the discharge start voltage of the discharge gap 13, the application of the test voltage is stopped (STEP 3). The determination unit 21 determines the deterioration state of the discharge gap 13 using the measured value of the discharge start voltage of the discharge gap 13 as a determination value (STEP 4). For example, if the determination value is in the range of 20.0 kV to 29.9 kV, it is determined that the discharge gap 13 is not deteriorated (STEP 5). If the determination value is 19.9 kV or less, or 30.0 kV or more, it is determined that the discharge gap 13 has deteriorated (STEP 6).

  As described above, by determining the deterioration state of the discharge gap 13 based on the measured value of the discharge start voltage of the discharge gap 13, in addition to determining the deterioration state of the zinc oxide element 12 described later, the discharge gap 13 It is also possible to determine the state of deterioration. Thereby, the reliability can be improved in determining the deterioration of the lightning arrester 11.

  Next, as a characteristic configuration of this embodiment, a procedure for determining the deterioration state of the zinc oxide element 12 by the deterioration diagnosis device 17 will be described in detail below with reference to FIG.

  The switching unit 19 sets a mode for determining the deterioration state of the zinc oxide element 12 (STEP 1). In this mode, the voltage supply unit 18 applies a DC test voltage between the power application side terminal 15 and the ground side terminal 16 of the lightning arrester 11. In the test voltage application (first time) in this mode, for example, the test voltage is increased at a rate of about 30 kV / s (STEP 2). In this way, by increasing the test voltage at once, the processing time is shortened when applying the test voltage a plurality of times (for example, five times) as will be described later. In this mode, it is not necessary to consider variations in the discharge start voltage of the discharge gap 13.

  When the test voltage is increased to reach the discharge start voltage of the discharge gap 13, the application of the test voltage is stopped (STEP 3). By stopping the application of the test voltage, the terminal voltage of the lightning arrester 11, that is, the voltage between both terminals of the lightning arrester 11 and the grounding side terminal 16 is reduced to zero. For example, after 2 seconds have elapsed from the gap discharge, the application of the test voltage (second time) is started again, and the test voltage is increased at once in the same manner as in the first time (STEP 4). When the test voltage is increased to reach the discharge start voltage of the discharge gap 13, the application of the test voltage is stopped (STEP 5). By stopping the application of the measurement voltage, the terminal voltage of the lightning arrester 11 becomes zero.

  By repeating the start and stop of application of the test voltage described above up to five times, the output characteristics of the lightning arrester 11 as shown by the waveform in FIG. 4 can be obtained. As shown in the figure, since the first discharge start voltage V1 is lower than the second and subsequent discharge start voltages V2 to V5, the measured values are sampled after the second (STEP 6). Sampling of measured values from the second time to the fifth time is performed by the voltage measuring unit 20 in the following manner.

  In the voltage characteristics of the lightning arrester 11 shown in FIG. 4, for example, an enlarged time axis of the A part of the second waveform is shown in FIG. 5. As shown in FIG. 5, after the gap discharge, the voltage across the lightning arrester 11 decreases due to the stop of the application of the test voltage, but the residual voltage V corresponding to the characteristics of the zinc oxide element 12 becomes apparent for a very short time. . The residual voltage V is measured by the voltage measuring unit 20 within a specified time range T (for example, 100 μs to 200 μs) of the residual voltage V after a lapse of a certain time, which is an extremely short time from the gap discharge (STEP 7). The same applies to the third, fourth and fifth times.

  Here, the measurement value can be sampled based on the metastable residual voltage V by setting the range of 100 μs to 200 μs after a certain time has elapsed from the gap discharge as the sampling period. In other words, the residual voltage V is not stable until the time of 100 μs has elapsed from the gap discharge, which is inappropriate. In addition, after the time of 200 μs has elapsed since the gap discharge, the residual voltage V decreases, which is not suitable.

  In this specified time range T (100 μs to 200 μs), for example, the residual voltage V is measured at 5 points. The determination unit 21 adds the measurement values of 3 points excluding the maximum value and the minimum value among the measurement values of 5 points for the repetition of starting and stopping the application of the test voltage (4 times from the second time to the fifth time). Then, an average value obtained by dividing the total value by the total number of measurement values (12) is used as a determination value for deterioration of the zinc oxide element 12 (STEP 8).

  In the determination part 21, the deterioration state of the zinc oxide element 12 is determined based on this determination value. That is, since the residual voltage V in the defective product in which the zinc oxide element 12 is deteriorated is lower than the residual voltage V in the good product in which the zinc oxide element 12 is not deteriorated, the measured value is a residual voltage V lower than that of the good product. If there is, it can be determined that the zinc oxide element 12 is deteriorated. For example, if the determination value is 13.0 kV or more, it is determined that the zinc oxide element 12 has not deteriorated (STEP 9). If the determination value is 12.9 kV or less, it is determined as a defective product in which the zinc oxide element 12 is deteriorated (STEP 10).

  As described above, the application of the test voltage is repeated a plurality of times, and each time the test voltage is repeatedly applied, the residual voltage V is measured at a plurality of points in the specified time range T of the residual voltage V. The remaining measured values excluding the maximum value and the minimum value are added together for repeated application of the test voltage, and an average value obtained by dividing the total value by the total number of measured values is used as a judgment value for deterioration of the zinc oxide element 12. Thereby, the measurement error by the variation of the residual voltage V which generate | occur | produces for every measurement can be suppressed, and deterioration of the zinc oxide element 12 can be determined accurately.

  The deterioration of the zinc oxide element 12 varies depending on the polarity of the lightning arrester 11. For this reason, it is effective to carry out the deterioration determination of the discharge gap 13 and the deterioration determination of the zinc oxide element 12 described above in a state where the lightning arrester 11 is connected to the deterioration diagnosis device 17 with the opposite polarity to the above case. Since the procedure for determining the deterioration of the discharge gap 13 due to the reverse polarity and the determination of the deterioration of the zinc oxide element 12 is the same as that described above, a duplicate description is omitted.

  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.

11 Lightning protection equipment (lightning arrester)
12 Zinc Oxide Element 13 Discharge Gap 14 Insulation Enclosure 17 Deterioration Diagnosis Device 18 Voltage Supply Unit 20 Voltage Measurement Unit 21 Determination Unit

Claims (2)

Lightning protection based on the voltage characteristics of the lightning protection device when a test voltage is applied to the lightning protection device whose main part, in which the zinc oxide element and the discharge gap are connected in series, is covered with an insulation jacket, and the test voltage is increased. A deterioration diagnosis device for determining the deterioration state of equipment,
Applying a test voltage to the lightning proof equipment, increasing the test voltage and stopping the application of the test voltage when the discharge start voltage of the discharge gap is reached, and manifesting immediately after the application of the test voltage is stopped A deterioration diagnosis comprising: a voltage measurement unit that measures a voltage within a specified time range of the residual voltage; and a determination unit that determines a deterioration state of the zinc oxide element based on the measurement value of the residual voltage apparatus.   The deterioration diagnosis device according to claim 1, wherein the determination unit is configured to determine a deterioration state of the discharge gap based on a measured value of the discharge start voltage of the discharge gap.

Images