JPS6118113A - Monitoring device for running of transformer - Google Patents

Abstract

PURPOSE:To decide abnormality in a tap changer by detecting a level of vibration attended with rise-up of pressure in the inside of a tank or a accoustic level owing to the vibration, and taking the amplitude of a load current of a transformer into consideration. CONSTITUTION:A change-over switch 3 contained in a tank 1 and a tap selector 4 are coupled with a tap change-over drive device 2 disposed on the upper part of the tank 1 and a vibration detector 5 is mounted on the outer wall of the tank 1. A deciding device 6 is composed of a signal convertion circuit 7 for converting an output signal from the vibration detector 5 into a fixed electrical signal in accordance with the amplitude of the vibration, a filter circuit 8, a decision processing circuit 9 and a signal conversion circuit 12. The decision processing circuit 9 is supplied with a start signal 10 for changing-over taps too. The signal conversion circuit 12 converts a signal from a load current detector 11 in accordance with the amplitude of the signal into an electrical signal having a fixed level, and inputs the converted signal into the decision processing circuit 9. The signal is compared with a preset normal vibration level in the circuit 9, in which abnormality in the tap changer is decided when the measured equivalent vibration level is large, thereby to output an alarm.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a transformer operation monitoring device.
In particular, the present invention relates to a transformer operation monitoring device that performs early abnormality detection in a load tap changer by constantly monitoring the load tap changer of a transformer.

[Conventional technology]

The on-load tap changer of a transformer (hereinafter referred to as a tap changer) is used to temporarily short-circuit the taps of the tap windings in the transformer through a resistor or handle when changing the voltage ratio during one voltage application. If the tap switching mechanism does not operate normally, an excessive short circuit will occur between the taps of the tap winding, leading to a major accident. In order to prevent such accidents and ensure normal operation of the transformer, in the past, the number of times the tap changer was operated was monitored, and parts were replaced when the number of times the tap changer was operated was replaced. Since the switching operation was not observed, it was difficult to grasp the precursor phenomenon of an abnormality, and the method could not be said to be sufficient as an abnormality prediction method.

On the other hand, during a patrol inspection by one person, an abnormality may be discovered from the tap switching sound due to the difference from normal conditions, but this auditory abnormality detection requires a person to go near the transformer. , and that tap switching is occurring at that time.

The patrolman heard the switching sound of the target tap changer and found out that it was normal.
It requires a high level of proficiency on the part of patrol personnel only when various conditions are met, such as being able to judge abnormalities, and there are problems such as not being able to constantly monitor the system, making it insufficient as an abnormality detection method. there were.

[Summary of the invention]

The present invention aims to eliminate the above-mentioned drawbacks of the conventional tap changer monitoring method, and provides a transformer operation monitoring device that automatically detects abnormalities in a tough tap changer at an early stage from a constant level.

[Embodiments of the invention]

FIG. 1 shows an embodiment of the present invention, in which a tap switching drive device installed above a tank 1 of a tap changer is connected to a switching switch 3 housed in the tank 1. Furthermore, tap selector Hiro is combined.

A vibration detector 5 is mounted on the outer wall of the tank l.

The determination device 6 includes a signal conversion circuit that converts the output signal of the vibration detector j into a predetermined electric signal depending on the magnitude of vibration, a filter circuit, a judgment processing circuit D, and a signal conversion circuit/.
Therefore, the tap switching start signal lσ is also input to the 1 judgment processing circuit t. Signal conversion circuit/K is load current detector/
The signal from / is converted into a predetermined electrical level signal according to the magnitude of the current and inputted to one judgment processing circuit.

Next, the operation will be explained. When changing taps,
By releasing the mechanical energy accumulated in the spring etc. in the tap switching drive device fita, the contacts inside the switching switch 3 can be switched in a short time of about several tens of milliseconds.
Due to the mechanical forces generated at this time and the arc generated during switching, a pressure increase occurs, which causes the tank/wall to vibrate through the insulating oil in the tank/. Here, the magnitude of the load current considerably contributes to the magnitude of the arc energy. The vibrations generated in this way are detected by a vibration detector attached to the outer wall of the tank 1, converted into an electrical level signal by a signal conversion circuit, and judged through a filter circuit. In order to eliminate this problem, only the vibration signal for a certain period of time after receiving the tap switching activation signal io is taken in as correct information. If a mechanical malfunction begins to occur in the tap changer drive device or the switching switch 3, the tap switching time may become longer.

Due to the increased arc energy during switching, tank l
The vibration level also increases due to the increase in internal pressure. Therefore, in the judgment processing circuit, the load voltage I5! Convert it to an equivalent vibration level taking into account the magnitude of LL, and compare it with a preset normal vibration level. If the measured equivalent vibration level is more than N times larger than this set value, the tap changer is judged to be abnormal. and outputs a warning.

Figure 1 shows a second embodiment. In the embodiment shown in FIG. 7, the vibration level considering the preset load current LL was compared with the measured vibration level, but by providing the data storage arithmetic processing circuit 13 as shown in FIG. The arithmetic processing circuit 73 stores data such as measured vibration levels, and has a statistical processing function added thereto to determine that the stored data is abnormal. In this way, even more accurate abnormality prediction becomes possible.

As described above, in the first and second embodiments, the vibration of the tank was detected by the vibration detector 5, but in the third embodiment, the vibration was detected by the acoustic detector RIa, and the signal was processed by a similar determination device B. The same effect can be obtained.

It is also easy to understand that the same effect can be obtained even if an acoustic detector is placed near the tank instead of the vibration detector on the left in the second embodiment shown in FIG.

〔Effect of the invention〕

As is clear from the above description, this invention has the following features.

Detects the level of vibration accompanying pressure rise inside the tank, which is a precursor to tap changer abnormality, or the sound level caused by this vibration, and determines tap changer abnormality or signs of abnormality by considering the magnitude of the transformer load current. So,
This has the effect of automatically and accurately detecting abnormalities early.

[Brief explanation of the drawing]

Fig. 1 is a wiring diagram of the first embodiment of this invention, Fig. 1 is a wiring diagram of the second embodiment, and Fig. 3 is a connection diagram of the second embodiment.・Tap switching drive device, 3...Tap switching switch, Φ Tarap selector, S
...Vibration detector. 5a...Acoustic detector, 6...Determination device, ri...Signal conversion circuit, t...Filter circuit, 9...Judgment processing circuit, io
・・Tap switching start signal, //・Load current detector, /
/3: Data storage arithmetic processing circuit. In each figure, the same reference numerals indicate the same or corresponding parts. Flower 1 figure Flame 2 figure 3 figure 'IfAguchi 112 騨511bu) L, '\; le W:, 4 figure

Claims (4)

[Claims] (1) A vibration or acoustic detector placed in the on-load tap switching device of the transformer, a signal conversion circuit that converts the signal from this detector into an electrical signal, and the output and load of this signal conversion circuit. A judgment processing circuit that receives an on-load tap switching start signal and a transformer load current level signal and determines whether there is an abnormality in the on-load tap switching device based on the input level from the signal conversion circuit synchronized with the on-load tap switching start signal. A transformer operation monitoring device comprising: (2) Memorizes the vibration and sound levels when switching taps,
The claimed invention comprises a data storage arithmetic processing circuit that performs statistical processing based on the transformer load current and determines whether there is an abnormality in the on-load tap switching device based on the tap switching time based on the allowable value based on the statistical processing. A transformer operation monitoring device according to scope 1. (3) The transformer operation monitoring device according to claim 1 or 2, comprising a vibration detector mounted on the tank wall of the on-load tap changer. (4) Claim 1 or 2, which includes an acoustic detector located near the tank of the on-load tap switching device.
Transformer operation monitoring device described in Section 1.