JP2008130957A - Method of detecting tap position and accumulated number of operations of on-load tap changer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To automatically detect the tap position and count the accumulated number of operations without directly acquiring a tap position signal. <P>SOLUTION: A signal processing unit 5 obtains, through a receiver 6, one of torque waveforms which are output by a shaft torque sensor 4 and are respectively characteristic of six switching operation modes (rise/fall of inversion switching at which only a changeover switch 2a is activated, rise/fall of normal switching at which the changeover switch 2a and a tap selector 2b are activated, and rise/fall of transfer switching at which the changeover switch 2a, the tap selector 2b, and a transfer switch 2c are activated); determines the switching operation mode; and, in the respective cases of the inversion switching, normal switching, and transfer switching, outputs tap position data and the accumulated number of operations. In the case of rise, the tap position data to be output is obtained by adding "1" to the previous tap position data; and in the case of fall, the tap position data to be output is obtained by subtracting "1" from the previous tap position data. The accumulated number of operations to be output is obtained by adding "1" to the previous accumulated number of operations. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a tap position of an on-load tap changer and a method of detecting the cumulative number of operations.

  As a method of constantly monitoring the state of the on-load tap changer (LTC), the motor current and shaft torque for operating the LTC are measured to determine the switching mode, and the LTC tap position signal is detected directly from the LTC operating mechanism. There is a method for determining whether the LTC is normal or abnormal based on the management level set for each take-in and switching operation mode (see, for example, Patent Document 1).

JP-A-7-161551 (page 4-5, FIG. 1)

  However, when the shaft torque sensor is attached to the existing LTC, there is a problem that it may be difficult to directly detect and acquire the tap position signal from the LTC operation mechanism or the like.

  An object of the present invention is to determine the switching operation mode based on the measured shaft torque waveform without directly acquiring the tap position signal, and to automatically count the tap position and the cumulative number of operations. is there.

A load tap position and a cumulative number of operation detection method according to the present invention include a load tap changer including a switch, a tap selector, and a converter, and a shaft torque provided with the load tap changer on a drive shaft. In the on-load tap position and cumulative operation count detection method in the on-load tap changer switching operation monitoring device having an electric motor driven through a sensor,
Up / down of reverse switching where only the switching switch operates, up / down of normal switching where the switching switch and tap selector operate, and conversion switching where the switching switch, tap selector and converter operate Identifying each of the six switching operation modes from the torque waveform output by the shaft torque sensor characteristic of each of the six switching operation modes of rising and lowering,
When the identification result is inversion switching, normal switching, and switching switching, if it is up, the tap position is output by adding 1 to the tap position of the previous display, and if it is down, the tap of the previous display is output. The display of the tap position obtained by subtracting 1 from the position is output, and the cumulative operation count is a display obtained by adding 1 to the previous cumulative operation count.

An on-load tap changer comprising a change-over switch, a tap selector and a changer, and an on-load tap changer having an electric motor that drives the load tap changer via a shaft torque sensor provided on the drive shaft. In the load tap position and the cumulative number of operations detection method in the switching operation monitoring device,
Up / down of reverse switching where only the switching switch operates, up / down of normal switching where the switching switch and tap selector operate, and conversion switching where the switching switch, tap selector and converter operate Identifying each of the six switching operation modes from the torque waveform output by the shaft torque sensor characteristic of each of the six switching operation modes of rising and lowering,
If the identification result is reverse switching, and the switching operation mode is in the same direction as the previous switching operation mode, the tap position display is the same as at the end of the previous time, and the cumulative number of operations is 2 added to the previous cumulative number of operations. And
When the identification result is normal switching and the switching operation mode is in the opposite direction to the previous switching operation mode, the tap position is displayed by adding 1 to the tap position before the previous switching when the current switching is ascending. When the current switching is downward, 1 is subtracted from the tap position before the previous switching, and the cumulative number of operations is added to the previous cumulative number of operations.
If the identification result is changeover switching, and the tap position display is shifted and not the display output of the tap position where the converter operates, the tap position is corrected to the position where the converter operates, and the cumulative number of operations is Add the displacement of the tap position + 1,
When the identification result is not a changeover switch but a display output of a tap position at which the converter operates, the cumulative operation number is obtained by adding 2 to the previous cumulative operation number.

  According to the on-load tap position and accumulated operation count detection method according to the present invention, it is possible to monitor the tap position and the accumulated operation count online without directly detecting the tap position signal. The status information of the tap changer can be easily obtained, and the initial response can be implemented smoothly.

Embodiment 1 FIG.
FIG. 1 is an LTC switching operation monitoring device, FIG. 2 is a circuit diagram showing an LTC circuit configuration, FIGS. 3 to 5 are graphs showing torque waveforms acquired by an axial torque sensor, and FIG. FIG. 4 shows an example of a torque waveform at the time of LTC conversion up / down switching, and FIG. 5 shows an example of a torque waveform at the time of LTC reverse up / down switching.

  As shown in FIG. 1, the LTC switching operation monitoring device includes a load tap changer 1, an electric motor 3 that drives the load tap changer 1, and a shaft torque sensor 4 that is attached to the electric shaft of the electric motor 3. The bevel gear mechanism 6 for transmitting the driving force of the motor 3 to the on-load tap changer 1, the receiver 6 for receiving the torque waveform of the shaft torque sensor 4 and the operation signal of the motor 3, and receiving by the receiver 6. Signal processing unit that performs torque value conversion at each operation such as switching switch operation, LTC abnormality, switching mode discrimination, cumulative operation count, etc. based on the torque waveform 5.

  The on-load tap switch 1 provided in the transformer 2 includes a switching switch 2a, a tap selector 2b, and a converter 2c.

  First, the general operation of the on-load tap changer 1 in FIG. 1 will be described. In FIG. 2, a transformer winding 2d is a general on-load tap changer widely known from the prior art, which is constituted by a main winding 2da, a coarse tap winding 2db, and a dense tap winding 2dc.

  2 shows that the on-load tap changer 1 is in the upward direction, that is, in the tap position (hereinafter referred to as POS.) 4 and POS. POS.5 after the switch to 5 is completed. 5, the odd number side of the tap selector 2 b is turned on the tap 5, the even number side is turned on the tap 4, the converter 2 c is turned on the tap (+), and the switching switch 2 a is turned on the odd number side. A current path is formed by a path of 2da → coarse tap winding 2db → tap (+) → converter 2c → fine tap winding 2dc → tap 5 → tap selector 2a. From this state, the upward direction, that is, the POS. 5 to POS. 6, the even number side of the tap selector 2 b not in the current path is switched from the tap 4 to the tap 6, and then the switching switch 2 a is switched to the even side, and the POS. 6 into the input state.

  On the contrary, from the state shown in FIG. 2, the downward direction, that is, the POS. 5 to the original POS. In the case of returning to 4, since the even-numbered side of the tap selector 2b is already in the target tap 4 (hereinafter referred to as reverse switching), the tap selector 2b needs to perform a switching operation again. Absent. Therefore, the tap selector 2b does not perform the switching operation, and only the switching switch 2a performs the switching operation from the odd side to the even side, and the POS. 4 is in the input state. The converter 2c does not operate in any of the above switching operations. Switching in which the switching switch 2a and the tap selector 2b operate is called normal switching.

  The converter 2c operates when the POS. 10 to POS. POS.11 when switching to 11 and descending. 10 to POS. Only when switching to 9

  As described above, the operation of the on-load tap changer 1 has six types of operation modes. That is, only the switching switch 2a is operated to reverse the up / down switching, and the switching switch 2a and the tap selector 2b are used to perform normal switching of the up / down switching, the switching switch 2a, the tap selector 2b, There is a switching operation mode of switching between ascending and descending respectively by the operation of the converter 2c.

  In the conventional LTC switching operation monitoring device, for each switching operation mode, it is determined which of the six switching modes corresponds to the tap position signal detected directly, and then the abnormality of the LTC is determined by the acquired signal acquired from the torque sensor. Has been implemented.

  In the present invention, it is used that the torque waveform acquired from the shaft torque sensor 4 by the receiver 5 is characteristically different depending on each switching operation mode as shown in FIGS.

  In the torque waveform, the rotation direction of the motor 3 that is the driving source of the switching operation differs between the rising and lowering of the switching operation mode. Therefore, the torque applied to the shaft of the motor 3 is in the opposite direction. If a positive torque is applied, a negative torque is generated in the switching operation descending direction, and is reversed with respect to the time axis (horizontal axis) as shown in FIGS. 3 to 5 (a) and (b). It becomes a waveform.

  That is, when the torque output signal from the shaft torque sensor 4 is positive, it is clear that the direction of switching is upward, and when it is negative, the direction of downward movement is switched. It is possible to estimate the current tap position by determining and counting up / down from the torque signal. In addition, the cumulative number of operations can be specified by counting the number of operations for each switching operation mode.

  The six types of switching operation modes are determined depending on the switching tap position and switching direction of the on-load tap switching.

  The change-over switching in which the switching switch 2a, the tap selector 2b and the converter 2c operate operates only when switching at a determined tap position in ascending and descending, respectively, but FIGS. 4 (a) and 4 (b). A characteristic torque waveform different from the torque waveforms in the other switching operation modes is shown as in the example shown in FIG.

  Similarly, in the normal switching and the reversal switching, characteristic torque waveforms different from the torque waveforms in the other switching operation modes are shown as in the examples shown in FIGS.

  In the case of the reverse switching shown in FIG. 5, only the switching switch 2a is operated, so that the torque value is small and shows a relatively gentle torque waveform. In the case of the changeover switching shown in FIG. 4, a torque waveform having a large and sharp change in torque value due to the operation of the switch 2a, the tap selector 2b, and the changer 2c is shown. In the case of the normal switching shown in FIG. 3, in order to operate the switching switch 2a and the tap selector 2b, characteristics in the middle of the torque waveform in the case of inversion switching and in the case of switching switching are shown.

  The torque waveform in the switching operation mode having the above characteristics is taken into the signal processing unit 5 from the receiver 6, and the signal processing unit 5 performs the tap position by the calculation method shown below for each switching operation mode based on the characteristic torque waveform. And a signal to be displayed after correcting the accumulated number of operations and the deviation are output and displayed on a display device (not shown). Hereinafter, a calculation method for each switching operation mode will be described.

In the case of switching, the signal processing unit 5 determines whether the torque waveform of the shaft torque sensor 4 rises or falls in the waveform shown in FIG. → 9 is displayed, and the cumulative number of operations is displayed by adding 1 to the previous cumulative number.

In the case of reverse switching The signal processing unit 5 determines whether the torque waveform of the shaft torque sensor 4 rises or falls in the waveform shown in FIG. ) Is added to 1 to 5 and if it is lowered, 1 is subtracted from the previously displayed tap position (for example, 5) to display 4 and the cumulative operation count is displayed by adding 1 to the previous cumulative count. To do.

Normal switching The signal processing unit 5 determines whether the torque waveform of the shaft torque sensor 4 rises or falls as shown in FIG. 3, and if so, the tap position is changed to the previously displayed tap position (for example, 5). 1 is added to 6 and if it is descending, 1 is subtracted from the previously displayed tap position (for example, 6) and displayed as 5, and the accumulated operation count is displayed by adding 1 to the previous accumulated operation count. .

  According to the first embodiment, in the existing LTC or the like, the signal processing unit 5 determines the switching operation mode from the torque waveform of the shaft torque sensor 4, and the tap position and the cumulative number of operations that are switched for each switching operation mode are determined. Since the display signal to be displayed is output, it is possible to monitor the tap position and the cumulative number of operations on-line without directly detecting the tap position signal, and to easily obtain LTC status information from a remote location when a failure occurs. be able to. Thereby, initial response can be implemented smoothly.

Embodiment 2. FIG.
When the torque sensor signal corresponding to the switching operation mode is not acquired, or when the switching operation mode does not correspond to the tap position, a deviation occurs in the cumulative addition method. The second embodiment relates to this countermeasure method. Hereinafter, each switching operation mode will be described.

・ In the case of conversion switching Despite the current switching operation mode being the torque waveform of conversion switching, as a result of the accumulation so far, the display of the initial set tap position will shift for some reason and the converter will operate. If it is not the display output of the tap position, the tap position is corrected to the position where the converter operates, and the displacement of the tap position + 1 is added for the cumulative number of operations.

  If the current switching operation mode is not the torque waveform of switching, but is the display output of the tap position where the switching device operates, it is assumed that the switching mode has not been detected and the operation after switching It is determined that the current operation has been performed, and 2 is also added to the cumulative number of operations.

In the case of reverse switching If the switching operation mode is in the same direction as the previous switching operation mode (for example, descending), the switching operation mode (raising) opposite to this time that could not be detected by the torque sensor 4 was once. The display of the assumed tap position is the same as at the end of the previous operation, and 2 is added to the cumulative number of operations (for example, when the tap position after the end of the previous operation was “3”, it was not detected in between. (Assuming that 3 → 4 has been switched once, the display of the tap position after the end of the current operation is also “3”).

・ Normal switching If the switching operation mode (for example, descending) in the opposite direction to the previous switching operation mode was detected, the torque sensor 4 could not detect, but there was one switching operation mode (raising) opposite to this time. The display of the deemed tap position accumulates the current switching to the tap before the previous switching, and adds 2 to the cumulative number of operations (for example, the tap position display before the previous operation start is “3”, and this time the normal increase) In the case of switching, assuming that there was one switching of 2 → 3 that could not be detected by the torque sensor after the switching operation of 3 → 2 detected by the previous torque sensor, this switching is regarded as 3 → 4.) .

  Further, when switching is performed beyond the upper and lower limit taps, the display of the tap position is set to the upper limit or the lower limit, and the cumulative operation count is calculated by adding the upper and lower tap positions and the display tap displacement +1 due to accumulation.

  According to the second embodiment, even when a torque sensor signal corresponding to the switching operation mode is not acquired or when the switching operation mode does not correspond to the tap position, the correct tap position and the cumulative number of operations can be estimated. it can.

Embodiment 3 FIG.
When the switching operation is performed manually or the like, the shaft torque sensor 4 cannot grasp the switching operation.

  The third embodiment includes a mechanical operation signal output device and its detector when a manual switching operation is performed. This mechanical operation signal output device can output signals in all switching operations. That is, when a manual switching operation that cannot be acquired by the shaft torque sensor 4 is performed, the cumulative number of operations can be accurately grasped by inputting the signal of the output device to the signal processing unit 5. The cumulative number of operations can be corrected.

Embodiment 4 FIG.
In the fourth embodiment, the signal processing unit 5 has a function of detecting the LTC switching operation time from the output waveform of the shaft torque sensor 4. The signal processing unit 5 compares the actual LTC switching operation time with the normal switching time, and determines whether there is an abnormality in the LTC switching operation based on whether or not the LTC switching operation time is within the normal switching time.

  When the switching operation is normally performed, the operation time is a value of 5 to 6 seconds as shown in the torque waveforms shown in FIGS. 3 to 5, and the switching time at the normal time is set by giving a width to this value in advance. Value.

  The tap position of the on-load tap changer and the accumulated operation number detection method according to the present invention can be effectively used for the on-load tap changer switching operation monitoring device.

It is a block diagram which shows the LTC switching operation | movement monitoring apparatus. It is a circuit diagram which shows the circuit structure of LTC. It is a graph which shows the torque waveform acquired by the axial torque sensor. It is a graph which shows the torque waveform acquired by the axial torque sensor. It is a graph which shows the torque waveform acquired by the axial torque sensor.

Explanation of symbols

1 Tap selector at load, 2 Transformer, 2a Switching switch, 2b Tap selector,
2c converter, 2d transformer winding, 2da main winding, 2db coarse tap winding,
2dc dense tap winding, 3 electric motor, 4 axis torque sensor, 5 signal processing unit,
6 Bevel gear mechanism.

Claims (4)

On-load tap changer having an electric motor driven via a shaft torque sensor provided with the load tap changer on the drive shaft, and a load tap changer comprising a change-over switch, a tap selector, and a converter In the load tap position and the cumulative number of operations detection method in the monitoring device,
Up / down of reverse switching where only the switching switch operates, up / down of normal switching where the switching switch and tap selector operate, and conversion switching where the switching switch, tap selector and converter operate Identifying each of the six switching operation modes from the torque waveform output by the shaft torque sensor characteristic of each of the six switching operation modes of rising and lowering,
When the identification result is inversion switching, normal switching, and switching switching, if it is up, the tap position is output by adding 1 to the tap position of the previous display, and if it is down, the tap of the previous display is output. A method for detecting a load tap position and a cumulative operation count, wherein a display of a tap position obtained by subtracting 1 from a position is output, and a cumulative operation count is output by adding 1 to the previous cumulative motion count. On-load tap changer having an electric motor driven via a shaft torque sensor provided with the load tap changer on the drive shaft, and a load tap changer comprising a change-over switch, a tap selector, and a converter In the load tap position and the cumulative number of operations detection method in the monitoring device,
Up / down of reverse switching where only the switching switch operates, up / down of normal switching where the switching switch and tap selector operate, and conversion switching where the switching switch, tap selector and converter operate Identifying each of the six switching operation modes from the torque waveform output by the shaft torque sensor characteristic of each of the six switching operation modes of rising and lowering,
If the identification result is reverse switching, and the switching operation mode is in the same direction as the previous switching operation mode, the tap position display is the same as at the end of the previous time, and the cumulative number of operations is 2 added to the previous cumulative number of operations. And
When the identification result is normal switching and the switching operation mode is in the opposite direction to the previous switching operation mode, the tap position is displayed by adding 1 to the tap position before the previous switching when the current switching is ascending. When the current switching is downward, 1 is subtracted from the tap position before the previous switching, and the cumulative number of operations is added to the previous cumulative number of operations.
If the identification result is changeover switching, and the tap position display is shifted and not the display output of the tap position where the converter operates, the tap position is corrected to the position where the converter operates, and the cumulative number of operations is Add the displacement of the tap position + 1,
When the identification result is not a changeover switch but is a display output of a tap position at which the converter operates, the cumulative operation count adds 2 to the previous cumulative operation count, Cumulative operation count detection method. 3. The load tap position and accumulated operation frequency detection method according to claim 1, wherein the switching of the load tap changer is separately detected as a mechanical operation signal. 2. The switching operation time in the torque waveform output from the shaft torque sensor is compared with a preset normal switching time to determine whether or not the switching operation of the on-load tap changer is abnormal. Alternatively, the load tap position and the cumulative number of operations detection method according to 2.

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