JPS6355648B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an external diagnostic method for gas-insulated switchgear, which makes it possible to easily and sensitively predict failures of gas-insulated switchgear, particularly mechanical abnormalities in operation.

Analyzing the cause of the failure of the switching equipment indicates that it is inoperable,
It is known that so-called mechanical failures such as malfunctions, air leaks, oil leaks, and breakages account for more than 90% of all failures. Regarding oil leakage and air leakage,
Although it is possible to issue alarms and take countermeasures before switching equipment loses its original function using pressure relays, etc., it is extremely difficult to detect malfunctions and take countermeasures in advance when it comes to inoperability or malfunctions. It was difficult. The reason for this is due to the function of switchgear, which in most cases is in a stationary state without operating during normal times, and must operate normally if an abnormality occurs in the power system. There is.

Hereinafter, in order to make the explanation more concrete, the explanation will be given by taking as an example a disconnection switch, which particularly requires reliability in terms of its mission among switching equipment. FIG. 1 is a structural diagram of a tank-type gas shield and disconnector. 1 is a gas tank that is filled with an insulating gas such as SE ₆ gas.
2 is a cutaway section, and although not shown, has an arc extinguishing chamber built inside. Reference numeral 3 denotes a pusher, and 4 an insulated operating rod, which serves to transmit and drive the operating force from the driving cylinder section 5 in the air to the shear cutting section 2. Reference numerals 6 and 7 designate control units for tripping and closing, respectively, which are comprised of valve devices that guide operating fluid (not shown) into the drive cylinder unit 5 in response to a tripping signal or closing signal. Although it is not clear because the figure is a cross-sectional view, 8 is an operating lever placed in the air outside the tank, while 9 is an operating lever placed inside the gas tank 1. These operating levers 8 and 9 are rotated, respectively. It is connected to a shaft 10, with which gas sealing takes place. That is, the rotating shaft 10 penetrates the tank 1. The link 11 is a transmission link for converting the linear motion of the drive cylinder portion 5 into the rotational motion of the air lever 8.

FIG. 2 is a detailed view of the arc chamber portion of the gas shield and disconnector described above. In the figure, 15 indicates a part of the sliding electrode (arc contact movable side) which is driven from the outside via an insulated rod, and 16 is a fixed arc electrode facing the movable arc electrode 15. Reference numeral 18 denotes a support for the fixed arc electrode 16, and although not shown, it also serves as a part of the contact of the main electrode. Fixed arc electrode 16
is firmly fixed to the support 18 with a tightening nut 17, for example, so as not to loosen. 12 is a shield plate attached to alleviate the electric field, 13 is a connecting conductor, and 14 is a terminal block.

BACKGROUND OF THE INVENTION With the increase in demand for electricity in recent years, all switchgear equipment, including circuit breakers, have become higher in voltage and capacity, and the impact on society of their failures is expected to be enormous and serious. Therefore, it is strongly desirable to improve the reliability of the trench breakers that make up the power system by predicting mechanical failures, which account for the majority of failures, in advance and taking countermeasures. It is rare.

Conventionally, the JEC-181 method has been commonly used to confirm the mechanical reliability of a breaker.
(1975), but it is customary to conduct a 10,000-times continuous opening/closing test as a reference test. It is well known among manufacturers, users, etc. related to switching equipment that during these tests, the opening time,
The stroke of the moving part, the closing time, the operating voltage, etc. are measured at the same time, and furthermore, the operating voltage, pressure, and control voltage are to be tested not only at the rated value but also at the highest and lowest positions. JEC-181 also applies to combinations of these values.
Manufacturers conduct factory tests using a combination of these tests to confirm product reliability before shipping.

However, opening/closing devices such as wire breakers need to operate in an extremely short period of time due to their functions, and therefore require a great deal of operating force. As mentioned above, the structure of the shingle breaker often uses bolts for fastening. For these, double nuts, folding washers,
The best screw locking methods currently known, such as pins and liquid locking agents, are used as appropriate, taking into account the location and use. However, as described above, the operating forces of the combs and breakers are strong, and an impactful force acts on each fastening portion, working in the direction of loosening them.

According to recent research results, it is now possible to predict the amount of wear on electrodes due to current breakage, based on information such as the number of operations and the breakage current. With the introduction of low-speed drive methods, verification methods for checking wear and mechanical operation are being established, but past accidents are often caused by loose fasteners. In order to improve the reliability of disconnectors, it is extremely important to establish a technology to check the condition of screw fasteners from the outside.

Therefore, if this technology can be solved, the chances of overhauling and inspection will be reduced, and the effect of contributing to improving the operating rate of equipment, shortening power outage periods, and saving labor will be enormous. Additionally, if the product is unnecessarily disassembled and reassembled many times, there is an increased chance of human error being introduced, and there are cases in which a stable operating condition is adversely affected, but this can also be prevented. .

The present invention has been made in view of the above points, and consists of a spring mass vibration system having a natural frequency that does not cause any actual operational damage inside the device, and which is externally vibrated and internally connected by the vibration response at this time. The purpose of the present invention is to provide an external diagnosis method for abnormalities in switching equipment that detects loosening of parts.

An embodiment of the present invention will be described below with reference to the drawings.
In the following figures, the same parts as in FIGS. 1 and 2 are designated by the same numbers, and their explanation will be omitted unless necessary.

FIG. 3 is a diagram for explaining one embodiment of the present invention, and is a detailed diagram of the arc extinguishing chamber portion. That is, in this example, for example, a stud 2 is attached to one end of the fixed electrode 16.
A spring plate 23 having elasticity in the axial direction and a donut-shaped weight 24 are attached to the end portion 21 of the spring plate 21 through the 0 and tightened with a nut 22. In addition, Locknut 1
Attach this firmly in step 9. The weight 24, stud end 21, etc. are appropriately rounded as shown in the figure in order to alleviate the electric field to the ground. In short, in this embodiment, a part of the arc extinguishing chamber has appropriate damping and constitutes a single degree of freedom vibration system with a constant natural frequency. From the viewpoint of maintenance and operation, it is desirable to avoid resonance at twice the excitation current frequency, that is, 100Hz or 120Hz, which occurs when power is applied to the disconnector. In addition, the natural frequency is set to withstand the strong excitation force when the breaker operates, but
It is better to provide non-linear spring characteristics. In addition, if multiple vibration systems are installed as necessary, and the natural frequencies of each vibration system are slightly different from each other, it will be possible to detect abnormalities in the measurements described later.
This makes it possible to point out things more clearly.

FIG. 4 is an example of a configuration for measurement based on the embodiment of FIG. That is, an electromagnetic vibrator 25 and a load cell (impedance head) 26 are attached to the link 11 in the air outside the tank 1.

FIG. 5 is a circuit diagram showing the relationship between the measuring system and measuring instruments configured as described above. In the figure, 27 is a signal cable of the electromagnetic exciter 25, and 28 is a frequency sweep type or random signal oscillation or amplifier. The output of the oscillator is branched by a signal cable 29 and connected to one channel of a data recorder 33 for recording. Further, the output of a load meter (impedance head) 26 mounted coaxially with the electromagnetic vibrator 25 is input to an amplifier 31 via a cable 30, and connected to another channel of the data recorder via a signal cable 32. The output of the data recorder 33 becomes the input of the signal analyzer 36 via signal cables 34 and 35.
Here, the ratio of the excitation force F to the acceleration signal (A...the output of the impedance head 26), that is, the mechanical impedance and its phase difference are calculated and displayed. Here, in order to explain the present invention, the data recorder 3
3 has been described, but it is of course unnecessary when performing mechanical impedance analysis on site.

Figure 6 shows an example of the results measured by this measurement system under normal conditions, with the mechanical impedance F/V of two internally installed vibrators plotted on the vertical axis.
It is expressed with frequency Hz on the horizontal axis.
Furthermore, FIG. 7 shows an example of experimental results when internal components become loose.

Next, the operation of the present invention will be explained. Strongly connected structures ensure the transmission of vibrational force, and due to resonance, the impedance response also has the characteristic of a sharp peak. However, if a slight loosening occurs in a part of this bond, the transmission of elastic waves at the boundary of the structure becomes extremely poor. Internal loosening can be detected using this phenomenon, but the important thing here is that it is necessary to vibrate one end of the structure and detect it at the other end. Conventional electric machines could not be used due to their construction. In view of this, as mentioned above, the present invention attempts to solve the problem by configuring a vibration system within the device that does not cause any actual operational damage, and by causing this to resonate from one side, it constitutes a single vibration source. be. In other words, as shown in Figure 6, for the response to a normal product with no abnormalities,
In FIG. 7, the frequency response of F ₁ ' is extremely reduced, and it can be detected from the outside that the path in this area is loose.

As described above, the external diagnosis method according to the present invention provides the following advantages.

(1) Since there is at least one signal source inside the breaker, it is possible to detect loosening of fasteners based on this signal source.

(2) By placing multiple signal sources depending on the internal structure, it is possible to extract each signal and specifically point out in which route a problem is occurring.

(3) If internal vibration induces random signals such as chatter due to loosening in extreme cases,
By detecting this at different points and finding the cross-correlation, it is possible to locate the part that is causing chatter in relation to the speed of sound.

(4) It can be easily applied without the need for disassembly or inspection.

[Brief explanation of the drawing]

Fig. 1 is a structural diagram of a tank-type gas shield breaker showing a cross section of the main part, Fig. 2 is a partial structural diagram of the arc extinguishing chamber shown in Fig. 1, and Fig. 3 is a structural diagram of a tank-type gas shield breaker showing the main parts in cross section. Figure 4 is a configuration diagram for measuring the external diagnostic method, Figure 5 is a diagram showing an example of the measurement system for the external diagnosis method, and Figure 6 is the measurement system for the same external diagnosis method. FIG. 7 shows an example of measurement data for abnormality diagnosis. 19... Tightening nut, 20... Stud, 22
... tightening nut, 23 ... spring plate, 24 ... weight, 25 ... electromagnetic exciter, 26 ... impedance head, 28 ... oscillation amplifier, 31 ... amplifier, 33 ... data recorder, 36 ... ...Signal analyzer.

Claims (1)

[Claims] 1 Configure at least one spring mass vibration system having different natural frequencies that do not cause actual operational damage inside the switching equipment, excite this spring mass vibration system from the outside, and detect the vibration response at this time. An external diagnosis method for an abnormality in a switching device, characterized in that the occurrence of loosening and the location where the loosening occurs are estimated by comparing the waveforms of the response and the excitation.