JPH0775211B2 - Abnormality detection device for tap switching device under load - Google Patents

Description

TECHNICAL FIELD The present invention relates to a device for detecting a switching operation abnormality of a tap switching device under load used in an electromagnetic induction device such as a transformer.

[Conventional technology]

The load tap changer provided in the load tap change transformer connected to the power transmission and distribution system is composed of a load tap changer connected to each tap of the winding of the transformer and an operation mechanism for driving the load change tap changer. Become. The load tap changer is composed of a changeover switch that switches the load current, a tap selector that selectively connects with the tap, and a converter that switches the polarity or the transition. That is, the voltage of the grid is kept constant.

The tap switching device during load switches the taps of the transformer windings while the load current flows, and therefore the transformer tap windings are temporarily short-circuited between the switching target taps through a resistor or a reactor. Therefore, if an abnormality occurs in the tap switching mechanism and normal switching operation is not performed, an excessive short-circuit current may flow through the transformer tap winding, leading to a serious accident. Therefore, it is an important subject to detect the signs of abnormality of these switching operations at an early stage.

FIG. 5 is a block diagram showing an abnormality detecting device for such a conventional load tap switching device disclosed in, for example, JP-A-60-176213. In the figure, (1) is an operation signal transmitting section that sends an operation signal to the electric operation mechanism (2), (3) is a tap switch at load driven by the electric operation mechanism (2), and (4) is an operation signal. Switching detection section for detecting (5)
Is a torque sensor unit that detects the torque generated on the drive shaft of the electric operating mechanism (2), and (6) is an output from the memory circuit unit (7) that stores a normal torque pattern during normal switching operation and the torque sensor unit. An abnormality determination unit that compares the output from (5) to determine whether there is an abnormality, (8) is an abnormality determination unit (6)
Is an abnormality display unit for displaying the output of.

Next, the operation will be described. The electric operation mechanism (2) drives the load tap changer (3) in response to the operation signal from the operation signal transmitter (1) to start the switching operation. At this time, the torque generated on the drive shaft is detected by the torque sensor unit (5) and sent to the abnormality determination unit (6). The abnormality determination unit (6) compares and calculates the detected torque and the normal torque pattern from the storage circuit unit (7), and, for example, the torque of the drive shaft increases due to the abnormality of the switching mechanism, and the ratio between the two is set to a predetermined value. When the value exceeds the value, it is judged that there is a sign of abnormality or the occurrence of tap congestion, and a signal is output, and the abnormality display section (8) displays the content of the abnormality.

As described above, it is possible to detect the sign of abnormality in the switching operation of the load tap switching device at an early stage and prevent the spread to other devices at the time of a serious accident.

[Problems to be Solved by the Invention]

Since the conventional abnormality detecting device for the tap switching device during load is configured as described above, it is possible to detect the abnormality of the switching mechanism from the change in the torque generated in the drive shaft of the operating mechanism. Was not sufficient in terms of surely identifying and detection sensitivity.

That is, the operation of the switching switch, the tap selector, and the converter that constitute the load tap changer differs depending on the switching mode and switching direction, and it is not easy to determine in which element the abnormality has occurred. . Further, even if the switching operation is normal, the detected torque changes with time due to the familiarity of the movable parts, etc., so that the sensitivity of abnormality determination is reduced accordingly.

The present invention has been made in order to solve the above problems, and an object of the present invention is to obtain an abnormality detecting device for a load tap changer capable of determining an abnormality occurrence point and capable of detecting an abnormality with high sensitivity. To aim.

[Means and Actions for Solving the Problems]

An abnormality detection device for a load tap switching device according to the present invention is a torque sensor unit for detecting a torque generated on a drive shaft of an operating mechanism in a pattern related to a series of switching operations, and an operation of a switching switch at that time from an operation signal. There are a total of 6 types that are determined from the switching state and whether the switching switch is only the switching switch, the tap selector is operating, or both the tap selector and the converter are operating, and the switching direction is either up or down. Switching pattern discriminating section for discriminating which one of the switching patterns, a normal torque pattern storing section for storing a torque pattern during normal operation as a normal torque pattern for each of the six types of switching patterns, and the switching pattern discrimination. The normal torque pattern in the switching pattern is discriminated from the normal torque pattern storage section on the basis of the output of Those with an abnormal point determination unit for determining an operation abnormal part by comparing the output from the sensor unit.

The abnormal point determination unit compares and calculates the magnitude and time interval of each torque peak between the torque pattern from the torque sensor unit and the normal torque pattern from the normal torque pattern storage unit, and determines whether or not there is an abnormality or its sign, and whether there is an abnormality. In the case of, the occurrence location is obtained from the time zone and output.

Further, when a normal torque pattern correction unit that corrects the stored contents of the normal pattern storage unit from the tendency of changes in the output from the torque sensor unit is provided, it is detected when the load tap changer operates normally. The normal torque pattern correction unit detects the tendency for the torque to decrease, and accordingly reduces the normal torque pattern serving as a reference for determining whether or not there is an abnormality and increases the detection sensitivity.

Further, if the correction of the normal torque pattern is performed based on the reduction rate of the integrated value of the detected torque, the individual variations of the detected torque are absorbed and the correction operation is stabilized.

[Embodiment] FIG. 1 is a block diagram showing an abnormality detecting device for a load tap changer according to an embodiment of the present invention. In the figure, the operation signal transmission section (1), the electric operation mechanism (2), the load tap changer (3), the torque sensor section (5), and the abnormality display section (8) are the same as the conventional ones, and the description thereof is omitted. To do.
(9) is an integrating section that integrates the torque detected by the torque sensor section (5) for each switching operation, (10) is an operation signal from the operation signal transmitting section (1), and is detected by the torque sensor section (5) A storage unit (11) for storing the torque pattern relating to the series of switching operations and the integrated value from the integration unit (9), and which switching pattern the switching operation corresponds to from the operation signal according to the procedure described later. A switching pattern discriminating unit for discriminating, (12) a normal torque pattern storing unit for storing a torque pattern at the time of normal operation for each of a total of 6 types of switching patterns described later as a normal torque pattern, and (13) for storing from the storing unit (10). An abnormal point determination unit that detects the presence or absence of abnormalities in the switching operation or the abnormal point by comparing the detected torque pattern of (1) with the normal torque pattern from the normal torque pattern storage section (12). A normal torque pattern correction unit that corrects the stored value in the normal torque pattern storage unit (12) from the fluctuation tendency of the integrated value from the storage unit (10) when the determination unit (13) does not detect an abnormality or a sign thereof. .

2 to 4 show an example of actual measurement of the torque pattern detected by the torque sensor unit (5). First, FIG. 2 shows a switching switch, a tap selector and a converter in a series of switching operations. In the case of the switching pattern in which all three operate, as shown in the figure, the stored torque for driving the switching switch begins to be applied from time t1 and shows a relatively gradual increase tendency, and is eventually released to switch switching. Vessel works (time t
6). Then, during this period, the tap selector driving torque between the opening time t2 and the closing time t5 of the tap selector and the converter driving torque between the opening time t3 and the closing time t4 of the converter are added. .

FIG. 3 shows a case of a switching pattern in which the switching switch and the tap selector operate, and as shown in the figure, the stored torque for driving the switching switch is the same as in the case of FIG.
Torque for driving the tap selector is applied between time t2 and time t5 until the operation of the switching switch.

FIG. 4 shows a switching pattern in which only the switching switch operates.

As for the types of switching patterns, in addition to the above-mentioned three types of switching modes, the type of switching direction of up or down is added, and a total of 6
There will be types.

Here, the intention of distinguishing the type of the switching pattern, that is, the upward or downward direction, as the switching pattern is as follows. That is, in the thrust bearing of the worm gear mechanism, which is generally used in the middle of the drive shaft of the operating mechanism, particularly the thrust bearing of the input worm, the friction coefficient of the pressure receiving portion greatly differs depending on the rotating direction of the shaft. As a result, the detected value from the torque sensor unit (5) varies depending on whether the switching direction is up or down. Therefore, by taking into consideration the distinction between the two directions as the switching pattern, it is possible to make a reliable abnormality determination.

By the way, in the load tap changer, the converter operates only when changing from a specific tap position to an ascending or descending direction. Therefore, the switching pattern determination unit (11) determines whether or not the switching operation corresponds to the pattern shown in FIG. 2 based on the tap position number and the switching direction information of the operation signal.

In addition, in the load tap changer, when the change is made in the opposite direction to the change direction before the change, the tap selector and the changer do not operate, and only the changeover switch operates. Therefore, the switching pattern determination unit (11) determines whether or not the switching operation corresponds to the pattern shown in FIG. 4 from the transition of the operation signal in the switching direction.

The switching pattern determination section (11) is stored in the storage section (1
The switching pattern is determined based on the operation signal from (0), and the information is sent to the normal torque pattern storage section (12).

The abnormal point determination unit (13) compares the torque pattern at the time of the switching operation from the storage unit (10) and the normal torque pattern in the normal torque pattern storage unit (12) selected by the switching pattern determination unit (11). Perform comparison calculation. For example, in the case of the switching pattern shown in FIG. 2, the magnitude of each torque peak is compared with their time intervals. When the ratio (difference) between the two exceeds a predetermined set value, it is determined that there is an abnormality or that there is a sign of abnormality, and the location of the abnormality is specified from the occurrence time zone as described below.

Here, as a specific criterion for determining that there is a sign of abnormality, for example, it is appropriate to set the magnitude of the torque to more than twice the normal value. This is because the load tap changer standard (JEC-2220) requires a mechanical life of 800,000 times, considering that the sliding part wears and the torque gradually increases year by year. Is.

Further, as a specific criterion for determining that there is an abnormality, for example, the magnitude of torque is 5 times or more of the normal time, or the torque peak intervals t1-t2, t2-t3 ... Are 1.5 times or more of the normal time interval. Is set. This is because if there is such a change, welding of the movable contact of the load tap changer or seizure of the sliding member may occur.

The normal torque pattern correction unit (14) is for increasing the sensitivity of abnormality detection. That is, in general, it is often experienced that the driving torque of the movable part of the machine decreases as compared with the initial state due to the familiar effect. Therefore, in extreme cases, the drive torque is often less than half the initial value. Therefore, if the presence / absence of an abnormality is always determined based on a fixed criterion, the detection of the abnormality will be delayed or missed.

Therefore, the normal torque pattern correction unit (14)
The integrated value of the torque during that time is traced every 00 times, its fluctuation tendency is tested by the method of least squares, etc., and if it is recognized that there is a decreasing tendency, the decreasing rate is calculated and multiplied by the normal torque pattern. The stored value in the normal torque pattern storage section (12) is corrected. Then, the abnormal point determination section (13) performs the abnormality determination based on the corrected new normal torque pattern. As a result, the torque fluctuation due to the familiar effect described above is offset, and the abnormality detection sensitivity is improved accordingly.

It should be noted that the reason why the above-mentioned tendency of the torque decrease is judged by the integrated value is intended to absorb the variation in the torque at the time of individual switching and stabilize the correction operation.
In applying the present invention, it is not always necessary to use the integral value.

Furthermore, depending on the required accuracy of abnormality determination and the specific structure of the operating mechanism, there may be cases where there is no problem in practice without providing a normal torque pattern correction unit. In this case, the configuration of the detection device can be simplified accordingly. Has the advantage that

〔The invention's effect〕

Since the present invention is configured as described above, it becomes possible to detect the abnormality of the load tap changer or its symptom by specifying the occurrence location.

Further, when the normal torque pattern is corrected, the torque fluctuation amount due to the familiar effect of the movable part is absorbed, and the detection sensitivity is improved.

Further, in the case where the correction of the normal torque pattern is obtained from the variation tendency of the integrated value of the detected torque, the variation of the individual detected torque is absorbed by that amount, and the correction operation is stabilized.

[Brief description of drawings]

FIG. 1 is a block diagram showing an abnormality detecting device for a load tap switching device according to an embodiment of the present invention, and FIGS.
FIG. 5 is a characteristic diagram showing normal torque patterns in different switching patterns, and FIG. 5 is a block diagram showing a conventional abnormality detecting device for a tap switching device under load. In the figure, (1) is an operation signal transmitting section, (2) is an electric operating mechanism, (3) is a tap switch during load, (5) is a torque sensor section, (9) is an integrating section, and (10) is a memory. (11) is a switching pattern determination unit, (12) is a normal torque pattern storage unit, (13) is an abnormal point determination unit, and (14) is a normal torque pattern correction unit. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (3)

[Claims] 1. An abnormal operation of a load tap changer equipped with a load tap changer comprising a changeover switch, a tap selector and a converter and an operating mechanism for driving the load tap changer based on an operation signal. A torque sensor unit that detects the torque generated on the drive shaft of the operating mechanism in a pattern relating to a series of switching operations, and the operation of the switching switch at that time from the operation signal is only the switching switch. Which of a total of six kinds of switching patterns is determined depending on the switching mode and whether the operation involves the operation of the tap selector or the operation between the tap selector and the converter. Switching pattern discriminating section for discriminating whether or not the normal torque pattern is stored as a normal torque pattern for each of the above six types of switching patterns. Based on the outputs from the pattern storage unit and the switching pattern determination unit, the normal torque pattern in the switching pattern is selected from the normal torque pattern storage unit and compared with the output from the torque sensor unit to determine the abnormal operation part. An abnormality detection device for a load tap switching device, which is provided with an abnormality location determination unit. 2. The load according to claim 1, further comprising a normal torque pattern correction unit that corrects the stored contents of the normal pattern storage unit based on the fluctuation tendency of the output from the torque sensor unit when no operation abnormality is detected. Anomaly detection device for time tap switching device. 3. The normal torque pattern correction unit integrates the torque pattern output from the torque sensor unit, and when it is determined that the integrated value is in a decreasing tendency, the normal torque pattern storage unit stores the stored contents in the normal torque pattern storage unit according to the decreasing rate. The abnormality detecting device for the tap switching device during load according to claim 2, wherein the correction is performed.