JP2709216B2 - Monitoring device for load tap changer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an on-load tap switching device monitoring apparatus for monitoring a switching operation of an on-load tap switching device used in, for example, a transformer.

[0002]

2. Description of the Related Art In general, a load tap changer provided in a load tap change transformer connected to a power transmission and distribution system includes a load tap changer connected to each tap of a winding of a transformer. And an electric operation mechanism for driving the motor. Further, the on-load tap changer is constituted by a changeover switch for changing over a load current, a tap selector for making a selective connection with a tap, and a converter for changing polarity or transposition,
By appropriately operating these, the voltage of the transmission and distribution system is kept constant. The on-load tap switching device switches the taps of the transformer winding during load application in which a load current flows. Therefore, between the switching target taps, the transformer tap winding is temporarily short-circuited through a resistor or a reactor.
Therefore, if an abnormality occurs in the tap switching mechanism and a normal switching operation is not performed, an excessive short-circuit current flows in the transformer tap winding, which may cause a large accident. For this reason, it is an important subject to detect signs of these switching operations abnormally at an early stage.

FIG. 4 is a block diagram showing a conventional monitoring device for a tap change device under load. In the figure, reference numeral 1 denotes an electric operation mechanism for driving a load tap changer 7, and the power of the electric operation mechanism 1 is transmitted through a vertical connection shaft 2, a bevel gear mechanism 3 and a horizontal connection shaft 4 to a head case 5. Is transmitted to the gear device 6 of
The load tap changer 7 is driven. 8 is an electric operation mechanism 1
A torque detecting unit for detecting a torque generated in the vertical connecting shaft 2 when the motor is driven; a converting unit 9 for converting an output of the torque detecting unit 8 into an electric signal; A switching signal detection unit for detecting the switching operation of No. 7;
Numeral 11 denotes a judging unit for comparing the torque value at the time of a normal switching operation stored in advance with the output of the converter 9 to judge whether or not the on-load tap switching device is abnormal. It is a display unit to perform. Note that 1 to 7 constitute a load tap switching device, and 8 to 12 constitute a monitoring device.

Next, the operation will be described. In response to an external switching signal, the electric operating mechanism 1 drives the on-load tap changer 7 to start the switching operation. At this time, the torque generated in the vertical connecting shaft 2 is detected by the torque detecting unit 8, and the detected torque value is converted into an electric signal by the converting unit 9, and is determined by the determining unit 11.
To send to. The determination unit 11 takes in the torque value converted into the electric signal output from the conversion unit 9 based on the switching signal indicating the tap switching state output from the switching signal detection unit 10 every time the tap is switched, and The torque value converted into the electric signal at the time of the normal switching operation is compared. For example, when the torque of the connecting shaft 2 increases due to the abnormality of the switching mechanism and the ratio of both exceeds a predetermined value, there is a sign of abnormality, or It is determined that tap congestion has occurred and a signal is output, and the display unit 12 displays the content. As described above, the monitoring device early detects a sign of an abnormality in the switching operation of the on-load tap switching device,
In addition, it is possible to prevent a serious accident from spreading to other devices.

[0005]

Since the conventional monitoring device for the on-load tap-switching device is configured as described above, the abnormality of the on-load tap-switching device is determined from the change in the torque acting on the connecting shaft. However, the power of the electric operating mechanism is transmitted directly to the load tap changer via the coupling shaft, bevel gear mechanism, and gear device of the head case, and the dynamic operation in the electric operating mechanism is also possible. Due to the action of the brake, the torque value acting on the drive shaft such as the connecting shaft does not become zero when the tap switching is stopped, or the switching direction (up / down) of the on-load tap switch is the same due to long-term use. Even in this case, there is a problem that the torque acting on the drive shaft at the time of stoppage of the tap change changes due to the influence of play, meshing, and wear of the gears . When the switching direction of the on-load tap changer is reversed (when the switching is performed from ascending to descending and descending to ascending), the polarity of the torque is reversed by reversing the rotation direction of the drive shaft, and the electric operating mechanism is also used. the action and effect of the meshing of gears or the like of the dynamic brake of the inner, before the start of the change over DOO
By torque value and the torque value of the tap changer is stopped immediately after the changeover completion is different, based to the torque value before the start of the change over
When detecting the torque value at the time of switching, the torque value of the drive shaft accompanying the power of the electric operating mechanism cannot be accurately detected,
There is a problem that the accuracy of the abnormality determination is deteriorated.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and can accurately detect a torque value of a drive shaft associated with an operation of a load tap changer, thereby enabling highly accurate abnormality determination. It is an object of the present invention to obtain a monitoring device for a tap switching device under load.

[0007]

According to the present invention, there is provided a monitoring apparatus for an on-load tap changer, which is provided with an on-load tap changer and an electric operation mechanism for driving the above-mentioned on-load tap changer based on a switching signal. A torque detecting unit for monitoring a switching operation of the tap switching device, the torque detecting unit being attached to a drive shaft connecting the load tap changer and the electric operating mechanism, and detecting a torque value acting on the drive shaft; Tap switching completed based on torque value output from detector
A correction unit for detecting a torque value acting on the drive shaft immediately after the stop of the tap switching and correcting the torque value at the time of tap switching based on the torque value as a zero base, and the corrected torque value and stored in advance. A determination unit that compares a reference torque value and determines an abnormality of the on-load tap switching device.

[0008]

[Action] In the present invention, the torque value output from the torque detection unit, the tap changeover completion straight for each tap changer
By detecting the torque value at the time of subsequent tap change stop and correcting the torque value at the time of tap change using the value as the torque zero base, the load tap excluding the effects of gear play, meshing, wear, etc. The torque value of the drive shaft accompanying the operation of the switch is detected.

[0009]

[Embodiment 1] An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing one embodiment of the present invention, wherein numerals 1 to 12 are exactly the same as those of the conventional apparatus. 13 is provided between the conversion unit 9 and the determination unit 11, and is a tap immediately after the completion of the tap switching.
Correction unit for correcting the torque value of the tap switching torque value when flop switching stop as zero-based torque shows an example of the specific configuration in FIG. In FIG. 2, reference numeral 14 denotes a torque value converted into an electric signal output from the conversion unit 9 based on a switching signal indicating a tap switching state from the switching signal detection unit 10 every time the tap is switched, and the torque value Similarly, a zero-base detection circuit 15 for detecting and storing the torque value when the tap switching is stopped, similarly temporarily stores the torque value output from the conversion unit 9 based on the switching signal from the switching signal detection unit 10 to zero. A subtraction circuit that subtracts the torque value from the base detection circuit 14 as a zero base and outputs the result to the determination unit 11. FIG. 3 shows a switching signal indicating the switching state of the on-load tap changer 7 and an output of the conversion unit 9 when the tap switching is adjusted so that the value is positive (+) when the tap change is raised and negative (-) when the tap change is decreased. 7 shows a torque pattern output from the converter 9 and a torque pattern output from the corrector 13 after torque value correction when the on-load tap changer 7 is switched from ascending to descending before torque value correction.

Next, the operation of FIGS. 1 and 2 will be described with reference to FIG. In response to an external switching signal, the electric operating mechanism 1 drives the on-load tap changer 7 to start the switching operation. At this time, the torque generated in the vertical connecting shaft 2 is detected by the torque detecting unit 8, and the detected torque value is converted into an electric signal by the converting unit 9 and transmitted to the correcting unit 13. The correction unit 13 takes in the subtraction circuit 15 the torque value converted into the electric signal output from the conversion unit 9 based on the switching signal indicating the tap switching state output from the switching signal detection unit 9 every time the tap is switched, and temporarily The stored tap value is taken into the zero-base detection circuit 14 and the tap value immediately after the completion of the tap switching based on the torque value.
The torque value at the time when the switching is stopped is detected and stored. Then, the subtraction circuit 15 subtracts the torque value during tap change stop immediately after the completion of tap change stored in the base detection circuit 14 from the stored torque value during tap change ,
That is, the torque value at the time of tap switching is corrected based on the torque value during tap switching stop immediately after the completion of tap switching as a zero base, and the torque value of the drive shaft accompanying the switching operation of the on-load tap switch 7 is obtained. This will be described in more detail with reference to FIG. Now, in FIG. 3, for example, the output value of the converter 9 during the tap change stop after the completion of the tap change is changed by the torque correction Tuo (detected by the zero-based detector 14) at the time of the change in the tap change. The representative value of the output of the unit 9 is T
un, the representative value of the drive shaft torque associated with the switching operation of the on-load tap changer 7 during the tap-up switching, Tu, and the output value of the conversion unit 9 during the tap-switching stop after the tap-down switching is completed, the torque correction at the time of the dropping The minute value Tdo (detected by the zero-base detector 14), the representative value of the output of the converter 9 during tap down switching is Tdn, and the drive shaft torque accompanying the switching operation of the on-load tap switch 7 during tap down switching. Assuming that the representative value is Td, Tu = Tun−Too Td = Tdn−Tdo
Is subtracted by the subtraction circuit 15, thereby eliminating the effects of play, meshing, and wear of the gears of the drive mechanism, and the effects of reversal of the on-load tap changer 7, and accompanying the switching operation of the on-load tap changer 7. The torque value of the drive shaft can be accurately obtained (Td, Tdn, and Tdo are negative values). The torque value obtained in this way is sent to the determination unit 11, where the torque value is compared with a reference torque value stored in advance to determine an abnormality of the on-load tap switching device, and displayed on the display unit 12. I do. Also according to this embodiment,
The influence of the electric offset which may be caused by the temperature effect or the like on the torque detecting unit 8 can be removed, and the electric zero base of the converting unit 9 can be set arbitrarily, so that the troublesome zero point adjustment becomes unnecessary.

Embodiment 2 FIG. In the above-described embodiment, the case where the correction unit 13 is configured by the zero-base detection circuit 14 and the subtraction circuit 15 has been described. However, the output of the conversion unit 9 is periodically A / D-converted and stored, thereby storing the output. Each time the tap is changed from the torque pattern,
It is also possible to perform a subtraction process of extracting a torque value when tap switching is stopped immediately after the completion of tap switching, and subtracting the torque value from the stored torque pattern using the value as a torque zero base.

[0012]

As described above, according to the present invention, the switching operation of the on-load tap switching device provided with the on-load tap switching device and the electric operating mechanism for driving the on-load tap switching device based on the switching signal is monitored. A torque detector attached to a drive shaft connecting the load tap changer and the electric operating mechanism, and detecting a torque value acting on the drive shaft; and a torque value output from the torque detector. And a correction unit that detects a torque value acting on the drive shaft when the tap switching is stopped immediately after the completion of the tap switching, and corrects the torque value at the time of tap switching based on the torque value as a zero base. A comparison unit that compares the stored reference torque value and determines an abnormality of the on-load tap switching device, so that the bevel gear mechanism / gear device of the head case, and Dynamic braking in the dynamic operating mechanism, and the torque acting on the drive shaft to the tap changer is stopped immediately after the tap changeover completion zero base, also affect the play-engagement-wear such as gears, switching direction of the load tap changer Depending on (up / down), the torque acting on the drive shaft at the time of tap switching stop immediately after the completion of tap switching is zero-based, and the torque value output from the torque detecting unit is corrected every time the tap is switched, thereby driving the motor. The effects of play, meshing, and wear of the gears of the mechanism, and the effects of inversion of the tap changer under load are removed, and the switching operation of the tap changer under load , that is, at the time of reversal change (from rising to lowering)
It is possible to accurately detect the torque value of the drive shaft associated with the change from descending, descending to ascending) and accurately detect an abnormality or a sign of the load tap switching device.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing one embodiment of a monitoring device of a tap change device under load according to the present invention.

FIG. 2 is a block diagram showing an example of a main part of the present invention.

FIG. 3 is a diagram for explaining the operation of the present invention;

FIG. 4 is a configuration diagram showing a conventional monitoring device for a tap change device under load.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electric operating mechanism 2 Vertical connection shaft 3 Bevel gear mechanism 4 Horizontal connection shaft 6 Gear device 7 Load tap changer 8 Torque detection unit 9 Conversion unit 10 Switching detection unit 11 Judgment unit 13 Correction unit 14 Zero base detection circuit 15 Subtraction circuit

Claims (1)

(57) [Claims] 1. An on-load tap changer for monitoring a switching operation of an on-load tap changer provided with an electric operating mechanism for driving the on-load tap changer based on a switching signal. said attached to a drive shaft connecting the electric operation mechanism, a torque detection unit that detects a torque value that acts on the drive shaft, the tap changer is stopped immediately after the tap changeover completion from the torque value output from the torque detection unit and A correction unit that detects a torque value acting on the drive shaft and corrects the torque value at the time of tap switching based on the torque value as a zero base; and compares the corrected torque value with a reference torque value stored in advance. And a judging unit for judging abnormality of the on-load tap switching device.