JPH04137512A - Abnormality detector for on-load tap changer - Google Patents

Abstract

PURPOSE:To detect the abnormality or a sign of abnormality of an on-load tap changer by specifying the abnormal spot by discriminating the abnormal spot by comparing a normal current pattern from a normal current pattern storing section with the output of a current sensor section in a switching pattern. CONSTITUTION:A switching pattern discriminating section 11 discriminates a switching pattern on the basis of an actuating signal from a storing section 10 and sends the information to a normal current pattern storing section 12. An abnormal spot discriminating section 13 compares a current pattern at the time of switching operation from the storing section 10 with the normal current pattern in a normal current pattern storing section 12 selected by means the switching pattern discriminating section 11. When the ratio (difference) between both patterns exceeds a prescribed set value, the section 11 discriminates that abnormality or a sign of abnormality exists and specifies the abnormal spot from the time zone during which the ratio (difference) exceeds the preset value. Therefore signal detection and handling can be performed easily and any abnormal spot can be surely discriminated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a device for detecting abnormal switching operation of an on-load tap switching device used in electromagnetic induction equipment such as a transformer.

[Conventional technology]

The on-load tap changer installed in the on-load tap-changing transformer connected to the power transmission and distribution system consists of an on-load tap changer connected to each tap of the transformer winding and an operating mechanism for driving and operating the on-load tap changer. Become. Furthermore, the on-load tap changer consists of a switching switch that switches the load current, a tap selector that selectively connects to the tap, and a converter that switches polarity or shift. This keeps the grid voltage constant.

The on-load tap switching device switches the taps of the transformer windings during power training when the load current flows.For this purpose, the transformer tap windings are temporarily short-circuited between the taps to be switched through a resistor or an axle. Therefore, in the unlikely event that an abnormality occurs in the tap switching mechanism and the switching operation is not performed normally, an excessive short-circuit current may flow through the transformer tap winding, leading to a serious accident. Therefore, it is important to detect signs of abnormality in these switching operations at an early stage.

FIG. 5 is a block diagram showing an abnormality detection device for a conventional load tap changer of this kind disclosed in, for example, Japanese Patent Laid-Open No. 60-176213. In the figure, (1) is an operation signal transmitter that sends an operation signal to the electric operating machine 1 (2);
(3) is a load tap changer driven by the electric operation mechanism (2), (2) is a switching detection unit that detects the operation signal, and f51 detects the torque generated on the drive shaft of the electric operation mechanism (2). The torque sensor section (6) compares the output from the memory circuit section (7) which stores the normal torque pattern during normal switching operation with the output from the torque sensor section (5) to determine whether or not there is an abnormality. (8) is an abnormality display section that displays the output of the abnormality determination section (6).

Next, the operation will be explained. The electric operating mechanism (21) drives the on-load tap changer (3) to enter the switching operation based on the operation signal from the operation signal transmitter (1). At this time, the torque generated on the drive shaft or the torque sensor section 4 The abnormality determination unit (6) compares and calculates this detected torque with the normal torque pattern from the storage circuit unit (7), and determines, for example, if there is an abnormality in the switching mechanism. When the torque of the drive shaft increases and the ratio of the two exceeds a predetermined set value, it is determined that there is a sign of an abnormality or that a tap jam has occurred, a signal is output, and the abnormality display section (8) displays the details of the abnormality.

As described above, signs of abnormality in the switching operation of the on-load tap switching device can be detected at an early stage, and serious accidents can be prevented from spreading to other equipment.

[Invention or problem to be solved]

Since the conventional abnormality detection device for the tap changer under load is configured as described above, it is possible to detect an abnormality in the switching mechanism from the change in torque generated on the drive shaft of the operating mechanism. Detection is not always easy, and the output signal is weak, which makes handling of the signal complicated.

In addition, the switching switch, tap selector, and converter that make up the on-load tap changer operate differently depending on the switching mode and switching direction, making it difficult to determine whether the problem is caused by an abnormality or by other factors. There was a problem.

This invention was made in order to solve the above-mentioned problems, and it is easy to detect and handle the signal, and the location of the abnormality can be reliably determined. The purpose is to obtain a detection device.

[Means and effects for solving the problem] The abnormality detection device for the on-load tap switching device according to the present invention includes a current sensor unit that detects the current of the motor of the electric operation mechanism in a pattern related to a series of switching operations; Determine from the signal whether the operation of the switching switch at that time is only the switching switch, accompanied by the operation of the tap selector, or accompanied by the operation of both the tap selector and the converter. a switching pattern determining unit that determines which of the three switching patterns determined from the I mode is a cover turn; a normal current pattern storage unit that stores the current pattern during normal operation for each of the three switching patterns as a normal current pattern; and an abnormality location determination section that determines a normal current pattern in the switching pattern from the normal current pattern storage section based on the output from the switching pattern determination section and compares it with the output from the current sensor section to determine an abnormal operation location. This is the second one that has the following.

The abnormality location determination unit compares and calculates the magnitude and time interval of each current peak between the current pattern from the current sensor unit and the normal current pattern from the normal current pattern storage unit, and determines whether there is an abnormality or its sign, and whether there is an abnormality. In this case, the location where the occurrence occurs is determined from that time period and output.

〔Example〕

FIG. 1 is a block diagram showing an abnormality detection device for an on-load tap switching device according to an embodiment of the present invention. In the figure, the operation signal transmitting section (1), electric operating machine fl (21, on-load tap changer (3), and abnormality display section 6) are the same as those of the conventional one, and their explanation will be omitted. (9a) and (9b) are electric operation mechanisms (tffi that detect the current of the electric motor 21);
A sensor and a pattern converter that converts the current waveform obtained from the current sensor (9a) into a pattern output related to a series of switching operations, and together constitute a current sensor section (9). (10) is a storage unit that stores the operating signal from the operating signal transmitting unit (1) and the current pattern detected by the current sensor unit (9); (11) is a storage unit that stores the operating signal from the operating signal transmitting unit (1) and the current pattern detected by the current sensor unit (9); (12) is a switching pattern determination unit that determines which switching pattern applies; (12) is a normal current pattern storage unit that stores current patterns during normal operation for each of three types of switching patterns (to be described later) as normal current patterns; 13) is an abnormal location determining unit that compares the detected current pattern from the storage unit (10) and the normal current pattern from the normal current pattern storage unit (12) to detect the presence or absence of an abnormality in the switching operation or detect an abnormal location. .

Figures 2 to 4 show actual measurement examples of current patterns detected by the $ flow sensor section (9). In the case of a switching pattern in which all three parties operate,
As shown in the figure, the starting current first flows, and from time t1 it shifts to the stored current for driving the switching switch, exhibiting a relatively gradual increasing trend, and then is finally released and the switching switch operates (time t1). t6). During this period, the current for driving the tap selector between the opening time t2 and the closing time t5 of the converter, and the current for driving the tap selector between the opening time t2 and the closing time t5 of the converter are supplied.
Figure 3 shows the case of a switching pattern in which the switching switch and tap selector operate. The stored current is the same as in the case of FIG. 2, but a current for driving the tap selector is added between time t2 and time t5 until the switching switch operates.

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

In this way, there are a total of three types of switching patterns.

By the way, in the on-load tap changer, the converter operates only when switching from a certain tap position in the upward or downward direction.

Therefore, the switching pattern determining section (11) determines whether the switching operation corresponds to the pattern shown in FIG. 2 from the tap position number and switching direction information of the operation signal.

In addition, in the on-load tap changer, when switching in the opposite direction to the previous switching direction, both the tap selector and the converter do not operate, and only the switching switch operates. Therefore, the switching pattern determining section (11) determines whether or not the switching operation corresponds to the pattern shown in FIG. 4 from the transition of the switching direction of the operation signal.

The switching pattern determination unit (11) reads the storage unit (11) in the manner described above.
determine the switching pattern based on the operation signal from lO),
The information is sent to the normal current pattern storage section (I2).

The abnormal location determining unit (13) is configured to determine the Th current pattern switching pattern determining unit (1) at the time of the switching operation from the storage unit (10).
The normal $ flow pattern selected in step 1) in the normal $ flow pattern storage unit (I2) is compared with the normal $ flow pattern stored in the storage unit (I2).

For example, in the case of the switching pattern shown in FIG. 2, the magnitude of each current peak and their time interval are compared. and,
If the ratio (difference) between the two exceeds a predetermined set value, it is determined that there is an abnormality or a sign of an abnormality, and the location where the abnormality has occurred is identified from the time period in which it occurs, as described below.

Here, as a specific criterion for determining that there is a sign of abnormality, it is appropriate to set the magnitude of the current to be more than twice that of normal, for example. This is based on the standard for on-load tap changers (JEC-2220), which requires a mechanical life of 800,000 operations, and takes into consideration that the sliding parts will wear out and the current will gradually increase year by year. 6 In addition, as specific criteria for determining that there is an abnormality, for example, the magnitude of the current is 5 times or more than normal, or the current peak interval tl-t2. t2-t3... or 1 of the normal time interval.
．． It is set to 5 times or more. This is because if there is a change of this magnitude, welding of the movable contact of the load tap changer or seizure of the sliding member may occur.

Furthermore, when starting the electric operating mechanism, if the current generation time interval tO-tl is more than twice that of normal switching, an abnormality such as a stiffness in the tap changer drive system during load or an open phase due to loosening of the electric wire of the motor power source may occur. I judge that. This makes it possible to detect the phenomenon of inability to start.

In addition, if the current flow time of the motor is more than twice that of normal switching, it will be determined that there is an abnormal failure such as the inability of the motor power switch to open, and an output will be displayed to that effect. It is possible to detect the phenomenon of runaway due to the inability to open the electrode.

As described above, in this embodiment, abnormalities or their signs are determined based on the data of the motor current of the electric operating mechanism, so the detection means is simpler than the conventional case based on torque data. Furthermore, the S/N ratio as a signal is high, and the reliability of detection characteristics is improved.

〔Effect of the invention〕

Since the present invention is configured as described above, signal detection and handling are simple, and the detection characteristics are highly reliable.
Furthermore, it is possible to detect an abnormality or a symptom thereof in the on-load tap changer by specifying the location where the abnormality occurs.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an abnormality detection device for an on-load tap changer according to an embodiment of the present invention, and FIGS.
The figures are characteristic diagrams showing normal current patterns in different switching patterns, and FIG. 5 is a block diagram showing an abnormality detection device for a conventional on-load tap switching device. In the figure, (1) is an operation signal transmitter, (21 is an electric operating mechanism, (3) is a tap changer on load, (9) is a current sensor unit, (10) is a storage unit, and (II) is a switching pattern. The determination unit, (12) is the normal current pattern storage unit, and (13) is the abnormal location determination unit. In each figure, the same reference numerals indicate the same or equivalent parts. Agent: Patent Attorney Oiwa
Masuo 1st figure 3, Teiken A-rei Tatsua Kiriboshi uB Ta tj Maru f Nza Ip z Positive f electric L Nog turn J Otsu mo beg p Uraba Kan Aban dispatch

Claims (1)

[Scope of Claims] An on-load tap changer comprising a switching switch, a tap selector, and a converter, and an electric operating mechanism for driving the on-load tap changer based on an operation signal. In the device for detecting abnormal operation, a current sensor unit detects the current of the electric motor of the electric operating mechanism in a pattern related to a series of switching operations, and a current sensor unit detects the current of the motor of the electric operation mechanism in a pattern related to a series of switching operations; A switching pattern determination method that determines which of three switching patterns is determined based on the switching mode, whether the switching pattern is accompanied by the operation of the tap selector, or the operation of both the tap selector and the converter. a normal current pattern storage section that stores current patterns during normal operation for each of the three types of switching patterns as normal current patterns; and a normal current pattern storage section that stores the switching pattern from the normal current pattern storage section based on the output from the switching pattern discrimination section. An abnormality detection device for an on-load tap switching device, comprising an abnormality detection section for determining an abnormality in operation by selecting a normal current pattern and comparing it with an output from the current sensor section.