JP2010015873A - Surge counter with leakage current detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surge counter with a leakage current detector of high reliability suitable for application to a lightning arrester at a conversion station and capable of being downsized and manufactured economically. <P>SOLUTION: The surge counter with a leakage current detector to be used by connecting with a grounding line 2 of a lightning arrester 1 is composed of a serial structural body 10 integrated with a leakage current detector 11 having a protection discharge space 13 and adjusting resistors 14 connected in parallel and a surge counter 12 serially arranged on a grounding side of the protection discharge space 13. On an outside of the integrated serial structural body 10, an outer resistance 20 set up at a specific resistance value is fixed removable. The outer resistance 20 is connected in parallel with the leakage current detector 11 and the surge counter 12 of serial arrangement constituting the serial structure 10. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a surge counter with a leakage current detector, and more particularly to a surge counter with a leakage current detector provided on the grounding side of a lightning arrester used in an AC / DC converter station, a frequency converter station, or the like.

  In power systems, particularly AC / DC converter stations and frequency converter stations of 50 Hz and 60 Hz, many thyristors are used in converter circuits that perform frequency conversion. The thyristor used in the converter circuit of the converter station is equipped with a lightning arrester to prevent it from being adversely affected by the harmonic surge voltage generated during frequency conversion, especially the harmonic surge voltage applied during zero power factor (ZPF) operation. Installation has been done to protect the thyristor.

  Usually, a lightning arrester uses a lightning arrester molded with zinc oxide as a main component, and a plurality of lightning arresters are housed in an insulating container such as a soot tube. Naturally, even when this type of lightning arrester is used in the above-mentioned conversion station, it is necessary to constantly monitor its soundness.

  For lightning arrester monitoring, a surge counter is provided in series on the grounding side of the lightning arrester, and the number of lightning arresters is measured with the surge counter and used for maintenance management. The surge counter is provided with a current transformer on the grounding side of the lightning arrester, and the operating current of the lightning arrester taken out via the current transformer is measured by sending it to the counting unit, or as described in Patent Document 1, In addition, there is a configuration in which a protective discharge gap with a shunt resistor is provided on the grounding side of the lightning arrester, and a counting unit that converts the current into a current according to the amount of light during discharge of the protective discharge gap and counts the operation is provided.

  In addition, in order to detect the deterioration of a plurality of lightning arresters, a lightning arrester uses a leakage current detector that measures the leakage current flowing through the grounding line of the lightning arrester (see Patent Document 2 and Patent Document 3). These leakage current detectors are provided with a current detection current transformer in series on the ground side of the lightning arrester, and a light emitting element is connected between both ends of the secondary winding of the current transformer, and the light emitting element is connected via an optical fiber. In combination with a detector having an optical / electrical converter.

  By the way, the lightning arrester used in the above-mentioned converter station is applied with alternating current with superimposed harmonics even in a normal state without a lightning strike, so that the leakage current becomes larger than that of commercial frequency alternating current, and the alternating current Since the waveform is not a sine wave, there is a problem that the leakage current value varies.

  Therefore, for the lightning arrester for the conversion station, for example, two types of surge counters whose internal impedance is changed by changing the value of the internal resistance are used, and these two types of surge counters are connected in series to the grounding side of the lightning arrester, The soundness of lightning arresters is also determined from the leakage current values of both surge counters.

  However, when two types of surge counters are used in a lightning arrester for a conversion station, it is not economical and requires a large space for installing each surge counter. In addition, it takes a lot of time to adjust the internal resistance of each surge counter, and there is a drawback that a defect in the connection of the internal resistance cannot be easily detected from the outside.

  In order to improve the above-mentioned drawbacks and monitor the soundness of the lightning arrester for the converter station, a surge counter with a leakage current detector constructed by integrating both a leakage current detector and a surge counter into the case is standard. It is used on the ground side of a lightning arrester.

JP-A-62-193075 JP 7-244111 A JP 2000-228198 A

  However, when monitoring a surge arrester for a converter station, when using a surge counter with a leakage current detector that is integrated with a leakage current detector and surge counter in series, connected in series to the grounding wire of the surge arrester, It is becoming clear that there are such problems.

  That is, the total current flowing through the grounding wire of the lightning arrester connected to the surge counter with a leakage current detector is divided into, for example, a normal operation area where the total current is about 200 mA or less, and a surge current measurement area where the total current is about 200 A or more. When considering the intermediate region between the normal operation region and the surge current measurable region, the leakage current detector accurately determines the amount of leakage current in a certain total current range in the intermediate region. It was found that there is a possibility that it can not be displayed. In this case, a sufficient function as a surge counter with a leakage current detector cannot be achieved, and the reliability is lowered.

  An object of the present invention is to provide a surge counter with a leakage current detector that is suitable for use in a lightning arrester for a converter station, can be manufactured in a small size and economically, and can improve reliability.

  A surge counter with a leakage current detector according to the present invention is a series in which a leakage current detector having an adjustment resistor connected in parallel with a protective discharge gap and a surge counter provided in series on the ground side of the protective discharge gap are integrated. When connecting the structure to a grounding wire of a lightning arrester, an external resistor set to a predetermined resistance value is detachably fixed to the outside of the series structure, and the external resistor is arranged in series to constitute the series structure The leakage current detector and surge counter are connected in parallel.

  Preferably, the external resistor is composed of two resistor units formed in a divided manner and connected in series, or the external resistor is composed of two resistor units formed in a divided manner and connected in parallel.

  More preferably, when the external resistor is composed of two resistor units connected in series, one of the resistor units has a resistor whose resistance value is fixed, and the other of the resistor units is a resistor whose resistance value is adjustable. It is characterized by having.

  The surge counter with a leakage current detector according to the present invention is configured integrally with a leakage current detector having an adjustment resistor connected in parallel to the protective discharge gap and a surge counter provided in series on the ground side of the protective discharge gap. When connecting the series structure to the grounding line of the lightning arrester, an external resistance set to a predetermined resistance value is fixed to the outside of the series structure by detachably fixing two resistance units with a common mounting plate. One of the resistance units has a resistance with a fixed resistance value, the other of the resistance units has a resistance whose resistance value can be adjusted, and the resistance units are connected in series, and the external resistance Is characterized in that it is configured to be connected in parallel to a leakage current detector and a surge counter arranged in series constituting the series structure.

  Preferably, the ratio of the resistance value to the external resistor and the resistance value of the series structure including the leakage current detector and the surge counter is set to about 1:47.

  If a surge counter with a leakage current detector is configured as in the present invention, an external resistor is attached to the series structure, and the leakage current detector provided in series and the surge counter are simply connected in parallel. There is no need to modify the inside, and it is possible to economically manufacture and reduce the size of a lightning arrester for a converter station, and it is easy to install the lightning arrester on the ground side. Detection can be performed reliably.

  In addition, since the leakage current detector circuit and the external resistor are connected in parallel in the protective discharge gap connected to the grounding wire of the lightning arrester, the surge counter circuit can be opened compared to the case without an external resistor. Therefore, a highly reliable surge counter with a leakage current detector can be obtained as a lightning arrester for a conversion station.

  In addition, the external resistance is composed of two resistance units, and these are fixed to the outside of the series structure with a common mounting plate so that they can be attached and detached. One resistance unit has a resistance with a fixed resistance value, and the other When the resistor unit has a resistor whose resistance value is adjustable and is connected in series, the resistance value of the external resistor can be adjusted very easily.

  A surge counter with a leakage current detector according to the present invention has a series structure in which a leakage current detector having an adjustment resistor connected in parallel with a protective discharge gap and a surge counter provided in series on the ground side of the protective discharge gap are integrated. This series structure is used by connecting to the grounding wire of the lightning arrester. The integrated series structure has an external resistor set to a predetermined resistance value detachably fixed to the outside, and this external resistance is connected to the leakage current detector and surge counter arranged in series constituting the series structure. It is characterized by being connected in parallel.

  Hereinafter, a surge counter with a leakage current detector according to the present invention will be described with reference to FIGS. As shown in FIG. 1, the surge counter with a leakage current detector is composed of a series structure 10 in which the circuits of the leakage current detector 11 and the surge counter 12 are sequentially provided in series, and this series structure. 10 is connected in series to the grounding wire 2 of the lightning arrester 1.

  The circuit of the leakage current detector 11 constituting one side of the series structure 10 has a protective discharge gap 13 connected in series to the ground line 2 of the lightning arrester 1 and an adjustment resistor 14 connected in parallel to the protective discharge gap 13. The other parts have a general circuit configuration.

  The surge counter 12 that constitutes the other side of the series structure 10 and is provided in series on the ground side of the circuit of the leakage current detector 11 connects a circuit including the counter 16 to the current transformer 15 that engages with the ground line 2. Circuit configuration.

  The leakage current detector 11 and the surge counter 12 that are connected in series constituting the series structure 10 are connected in parallel with the series structure 10 portion according to the present invention, and an external resistor 20 set to a predetermined resistance value in advance as described later, The connection lines 23 and 24 are used for connection.

  As shown in FIG. 1, when an external resistor 20 is connected in parallel to a series structure 10 constituting a surge counter with a leakage current detector, a leakage current detector having an adjustment resistor 14 in a protective discharge gap 13 in the ground line 2. 11 circuit and the external resistor 20 circuit are connected in parallel.

  As a result, when the protective discharge gap 13 does not operate at all times, the total leakage current IT flowing in the ground line 2 of the lightning arrester 1 is the current ISC flowing in the circuit of the leakage current detector 11 and the current ISR flowing in the circuit side of the external resistor 20. At the same time, the flow is divided according to the resistance value.

  Therefore, even if the total current amount flowing through the grounding line of the lightning arrester is an intermediate region where the protective discharge gap 13 does not operate between the normal operation region and the surge current measurable region, the leakage current detector 11 causes the leakage current. Can be displayed accurately. Further, when only the series structure 10 serving as a surge counter with a leakage current detector is connected to the ground line 2 and used, the possibility of circuit opening at the surge counter 12 portion is reduced.

  In the example shown in FIG. 1, the external resistor 20 is composed of two resistor units 21 </ b> A and 21 </ b> B, and is connected in series by a lead wire 22 so as to have a predetermined resistance value. As described above, when the external resistor 20 is constituted by the two resistance units 21A and 21B, both of them are used by determining the resistance value as follows.

  That is, both of the resistance units 21A and 21B are used with a fixed resistance value, or a resistor having a fixed resistance value is used for at least one of the resistance units 21A connected in series, and the resistance value is set for the other resistance unit 21B. The resistance is made variable, and the total resistance value is set to a preset value.

  As described above, when the external resistor 20 is configured by using the resistance units 21A and 21B whose resistance values can be adjusted, the connection is made after the connection to the series structure 10 having the leakage current detector 11 and the surge counter 12. However, the resistance value of the entire external resistor 20 can be easily adjusted.

  The resistance value of the external resistor 20 or the like connected in parallel to the series structure 10 is used by appropriately setting the resistance value of the adjustment resistor 14 or the like provided in the circuit of the leakage current detector 11. For example, when the resistance value of the series structure 10 including the leakage current detector 11 and the surge counter 12 is 1, the resistance value of the external resistor 20 is set to a value smaller by one digit or more.

  More specifically, while the resistance value of the series structure 10 including the leakage current detector 11 and the surge counter 12 is 1, the resistance value of the external resistor 20 is set to a small value of about 1/47. . If it does in this way, the leakage current which flows into the grounding line 2 of the lightning arrester 1 will be shunted according to these resistance values to both the external resistance 20 side with small resistance value and the serial structure body 10 side normally.

  However, when a current of a certain value or more is applied to the external resistor 20, the protective discharge gap 13 in the series structure 10 is discharged, so that a current flows to the surge counter 12 side. 16 can be measured. For this reason, since the function required as a surge counter with a current detector is sufficiently fulfilled, the reliability as a lightning arrester for a conversion station is remarkably improved.

  As is well known, the series structure 10 includes a circuit of a leakage current detector 11 and a circuit of a surge counter 12 provided in series, as shown in FIGS. 2 and 3, for example, an insulating terminal 17 made of polymer resin and a ground. The side terminal 18 is housed and integrated in a container, or both circuits are molded and used integrally.

  As shown in FIGS. 2 and 3, the external resistor 20 is configured by configuring the resistance units 21 </ b> A and 21 </ b> B by disposing solid resistors in the respective cases or molding solid resistors. Both of these resistance units 21A and 21B are attached using upper and lower common attachment plates 25 and 26 formed in a U shape with a metal plate or the like.

  That is, the resistance units 21A and 21B are symmetrically attached to the two ends of the upper and lower common mounting plates 25 and 26, respectively, and are arranged outside the series structure 10, and then close to the outside of the series structure 10. The insulating terminal 17 and the ground side terminal 18 are utilized and fixed with a nut or the like so as to be detachable. As described above, when the external resistor 20 is attached to the outside of the series structure 10, the resistance value of the external resistor 20 that changes with time can be easily inspected.

  The external resistor 20 connected in parallel with the series structure 10 is connected to the insulation terminal 17 and the ground side terminal 18 by connection lines 23 and 24 in the illustrated example, but a part of the upper and lower common mounting plates 25 and 26. Can be used as the connection lines 23 and 24. In this case, the common attachment plates 25 and 26 to which the resistance units 21A and 21B are attached are naturally used while being partially insulated.

  The external resistor 20 in the above example has been described as being composed of two resistor units 21A and 21B connected in series. However, the two resistor units 21A and 21B may be connected in parallel or used. It is also possible to use one of the resistance values. In any of these cases, it is obvious that the same effect can be achieved if the series structure 10 is detachably fixed to the series structure 10 by a mounting plate or the like.

It is a circuit diagram which shows one Example of the surge counter with a leakage current detector of this invention. It is a schematic side view which shows the structural example of the surge counter with a leakage current detector of FIG. It is a schematic perspective view of the surge counter with a leakage current detector of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Lightning arrester, 2 ... Ground wire, 10 ... Series structure, 11 ... Leakage current detector, 12 ... Surge counter, 13 ... Protection discharge gap, 14 ... Adjustment resistance, 15 ... Current transformer, 16 ... Counter, 20 ... External resistance, 21A, 21B ... resistor unit, 22 ... lead wire, 23,24 ... connection wire.

Claims (6)

  A leak that connects a leakage current detector having an adjustment resistor connected in parallel with the protective discharge gap and a surge counter provided in series on the ground side of the protective discharge gap to the ground line of the lightning arrester. In the surge counter with a current detector, an external resistor set to a predetermined resistance value is detachably fixed to the outside of the series structure, and the external resistor is a leakage current detector arranged in series constituting the series structure. A surge counter with a leakage current detector, characterized by being connected in parallel to the surge counter.   2. The surge counter with a leakage current detector according to claim 1, wherein the external resistor is composed of two resistance units that are divided and connected in series.   3. The leakage current detector according to claim 2, wherein one of the resistance units has a resistance having a fixed resistance value, and the other of the resistance units has a resistance whose resistance value can be adjusted. Surge counter with.   2. The surge counter with a leakage current detector according to claim 1, wherein the external resistor is composed of two resistance units that are divided and connected in parallel.   A leakage connected to a grounding line of a lightning arrester by connecting a series structure integrally including a leakage current detector having an adjustment resistor connected in parallel with the protective discharge gap and a surge counter provided in series on the ground side of the protective discharge gap. In the surge counter with a current detector, an external resistor set to a predetermined resistance value by detachably fixing two resistor units with a common mounting plate is provided outside the series structure, and one of the resistor units is A resistor having a fixed resistance value, the other of the resistor units has a resistor whose resistance value can be adjusted, and the resistor units are connected in series, and the external resistor constitutes the series structure. A surge counter with a leakage current detector, characterized by being connected in parallel to a leakage current detector arranged in series and a surge counter.   6. The method according to claim 2, wherein a ratio between a resistance value of the external resistor and a resistance value of the series structure including the leakage current detector and the surge counter is set to approximately 1:47. Surge counter with leakage current detector.

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