JPS6319964B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a method for monitoring switching equipment, and particularly to a method for estimating the state of a contact.

(Prior art) In general, air, oil, or gas insulated switchgear, such as insulation breakers and disconnectors, are equipped with a fixed contact and a movable contact housed in a container, and the movable contact is used as an operating device. The electric circuit to which it is connected is then turned off and on by driving the actuator to open and close the circuit. This opening/closing operation wears out the contacts, but such damage to the contacts varies depending on the load condition and number of operations, etc., but these maintenance inspections should be carried out at regular intervals or during operation. Inspections are performed when a certain number of times is reached according to the record of the number of times. In such inspections, the only way to check for damage to the contacts is to disassemble the equipment, and the only way to decide whether to inspect is to do it periodically or based on the number of operations as described above.

(Problems to be Solved by the Invention) As described above, there has been a need for a good means of estimating the degree of contact wear, and it has been expected that disassembly and inspection at an appropriate time will be useful in preventing accidents.

The present invention has been made in view of the above points, and its purpose is to more accurately predict the degree of damage to contactors of switching equipment and equipment abnormalities, and to carry out maintenance work by carrying out inspections at appropriate timings. The object of the present invention is to provide a method for monitoring switching equipment that can achieve both economic efficiency in construction.

[Structure of the invention]

(Working Means to Solve the Problems) In order to achieve this object, according to the present invention, a fixed contact, a movable contact, and an operating section for driving a movable part having the movable contact are provided. A current transformer is connected to the switching equipment, and the movable part connected to the operation part is provided with a position detection device that detects the opening/closing position of the movable contact of this movable part. The arc generation time of the switching equipment can be measured using the signal obtained from the current transformer and the arc extinction time signal and arc generation time signal accompanying the switching operation obtained from the current transformer.

When a contactor of a switchgear opens and closes, unless the circuit voltage and current are below a certain limit (generally around 100V), an arc will occur and this will continue. This arcing is extremely hot and melts the contact material. It is generally known that the degree of melting varies depending on the magnitude and duration of the arc current and the material of the contact. That is, if the material of the contacts of the switching device is known in advance, the degree of melting (damage) of the contacts due to the switching operation can be estimated if the magnitude and duration of the arc current are known. Further, the opening/closing time of each opening/closing device is unique, and it is possible to estimate an abnormality in the mechanical device by measuring the time the operating rod passes through two points and comparing it with the initial value. The present invention is characterized by providing a method for monitoring switchgear that can more accurately predict damage to contacts of switchgear and equipment abnormalities, carry out inspections at appropriate timings, and achieve both maintenance and economical efficiency of construction. do.

(Example) An example of the present invention will be described below with reference to FIGS. 1 to 7. In a switching device such as a gas insulated disconnector, a movable contact 7 is connected to a high voltage conductor by a fixed contact 8, as shown in FIG. The movable contactor 7 is connected to an insulating rod 6 that electrically isolates the high voltage side and the operating section, is slidably held via a guide 5, and is connected to the lever 4 and main shaft 3 of the opening/closing mechanism section 1. Further, the main shaft 3 is rotated by an operating device (not shown) provided outside the opening/closing mechanism case 1a to perform opening/closing operations. The operating rod 2, which is connected to the insulating rod 6, moves linearly with the opening and closing operations, and is also connected to the main shaft 3.
It is also possible to perform rotational movement along with the rotation of . Each of the position detection devices described later is configured by linear motion or rotational motion.

If the opening/closing operation occurs when voltage is applied, the movable contact 7
An arc is generated between the fixed contact 8 and the fixed contact 8. The arc extinction point and arc generation point differ depending on whether the switching device is turned on or off.

1A and 1B respectively show the load fluctuation current waveform A and the stroke curve B of the movable contact 7 during the "cutting" or opening operation in which the movable contact 7 of FIG. 7 is driven to the right side in the figure; In figure a, the vertical axis is the current I
, time T is plotted on the horizontal axis, and the stroke distance L in the direction of arrow L shown in FIG. ₇ is plotted on the vertical axis in _FIG .
Time T is plotted on the horizontal axis. The load current decreases as the movable contactor 7 moves, and the point of decrease starts from a certain l ₀ characteristic of switching equipment and is at time t ₀ .
However, l ₀ is the instant of contact or separation. The extinction point depends on the atmosphere around the contact and the state of the contact, and the time t ₂ is not constant. That is, the period between t ₀ and _{t 2} is the arc current time. Further, at time t ₁ before time t ₂ , the stroke distance is l ₁ . θ ₀ and θ ₁ on the vertical axes shown in FIG. 1B correspond to distances l ₀ and l ₁ , respectively, and are rotation angles, respectively, as will be described later.

In Figures 2a and b, the movable contact 7 is “in” from open.
That is, the load fluctuation current waveform C and the stroke curve D of the movable contact 7 during the opening operation are shown, respectively.
In Fig. 2a, the vertical axis shows the current I, and the horizontal axis shows the time T. In Fig. 2b, the vertical axis shows the stroke distance L in the opposite direction to the arrow L shown in Fig. 7, and the horizontal axis shows the time. I'm taking T. The load current increases with the movement of the movable contact 7, and the point of increase is due to the characteristic of switching equipment.
It starts between l ₁ and l ₀ and is the point at time t ₂ . This increase point depends on the atmosphere around the contact and the state of the contact, and the time t ₂ is not constant. However, the point of increase is the point at which the load current becomes measurable.

In Fig. 3, as shown in Fig. 3a, a sensor part 13 is formed from a sensor of a movable part, for example, a magnet 10, and a sensor 11 of a fixed part, and when this magnet 10 moves in the X-axis direction and the Y-axis direction. As shown in FIG. 3b, the sensor section 13 has characteristics indicating an on region in which it operates and an off region in which it does not operate.

Next, in FIG. 4, the operating rod 2 is provided with movable sensors such as magnets 10a and 10b, and the fixed sensor 11 is attached to a suitable fixed portion around the operating rod on the right side of the magnet 10a and facing the operating rod. establish. Then, at the positions l ₀ and l ₁ shown in Fig. 1b, the sensor 1 of the fixed part
1 and the sensor of the moving part, that is, the magnet 10
For example, if magnet 10a is installed so that it corresponds to _l0 and magnet 10b is installed so that it corresponds to _l1 , the distance between the center points of magnets 10a and 10b is _l1 - _l0 = l. _d , and the first
Distance l ₀ to time t ₀ and distance l ₁ to time t ₁ as shown in figure b
It corresponds to

On the other hand, in a line in which a disconnector 15 and a current transformer 16 are connected to a disconnector 14 as shown in FIG. RMS calculation circuit 3
1, convert it to an effective value, and send that value to comparison circuit 3.
2, the reference value I ₀ , that is, generally the lowest value that can be measured by comparing it with the noise level, is defined as the reference value I ₀ , and the time when the reference value I ₀ becomes less than or equal to this reference value I 0 is defined as t ₂ , that is, the arc extinction time t. ₂ .

The time _difference t A between the time t ₂ obtained as described above and the time t ₀ at the instant of contact or separation of the movable contact
Then, the time difference t _A =|t ₂ −t ₀ | is obtained from the arithmetic circuit 33, and the arc time is obtained. This value of t ₂ −t ₀ is entered into the arc time absolute value display circuit 34, which displays it as an absolute value, because the strokes are reversed in the opening and closing operations and the time axis is reversed, as shown in FIG. .

Next, as a method for detecting equipment abnormalities based on arc time fluctuations, detection is performed from Δt = t ₂ − t ₁ shown in Figure 1b. (during operation), Δt is detected by a signal obtained mechanically from a mechanism position detection device and a signal electrically obtained from a current transformer.

Although the above-described detection device may be used as is to detect the position of the mechanism, a case will be described in which it is provided with separate functions. That is, when the arc extinguishment time (during the breaker, i.e., “open” operation) and the arc onset time (during the closing, i.e., “closing” operation) are extinguished, the arc extinguishment time t ₂ and t ₀ and any intermediate point are determined. It is formed so that t ₁ is located at the position t 1 and t ₁ is located on the L ₁ side from the arc generation time t ₂ at the time of injection. Then, the difference between the time signal obtained from the mechanism and the arc extinction time and arc generation time obtained from the current transformer obtained by the above operation, that is, Fig. 1 b and Fig. 2 b
The time comparison circuit 35 shown in FIG. 5 calculates the difference Δt from the difference shown in FIG. Therefore, device abnormality can be detected by displaying the abnormality.

Further, the time integral of the current transformation effective value between the time signals t ₀ and ^t ₂ obtained by the time addition circuit 37 of the monitoring device ₃₀ shown in FIG. By calculating the cumulative value of this current x time, it is possible to predict the degree of damage to the contacts of switching equipment.

Figure 6 shows P ₁ , P ₂ , P ₃ , P ₄ ,
It is a diagram showing the cumulative value of waveform I×T and IT of _P5 .

On the other hand, in cases where high-speed operation equipment such as a shield disconnector and sensor parts cannot be accommodated, a linear motion position detection device as described above may be used to transmit rotational motion to the operation shaft of the main electrode operation device of the main body of the equipment. Link. That is, as another embodiment of the present invention, the eighth
As shown in FIG. 9 and FIG. 9, the operating shaft 25 is connected to the main shaft through a gear, for example, and the sensor section 13
Install. And this slit plate 23
In order to detect the rotational position of the operating shaft 25 from the position of the slit 23a, a sensor section 13 consisting of an optical sensor 20 and a slit plate 23 having the slit 23a is provided to measure the position.

The optical sensor 20 produces an output Vout that allows the light emitted from the light emitting diode 21 to be detected by, for example, a phototransistor 22, as shown in FIG. A slit 23a is cut on the slit plate 23 which interlocks with the operating shaft 25 shown in FIG. A signal is obtained through light only when it passes through the slit 23a during operation. Arrow H shown in FIG. 9a indicates the direction of movement when "closed", arrow K indicates the direction of movement when "open", and θ ₀ ,
θ ₁ and θ _d are rotation angles, respectively.

〔Effect of the invention〕

As described above, the present invention provides a position detection device in a movable part,
The arc time is measured based on the signal mechanically obtained from this position detection device accompanying the opening/closing operation, and the arc generation time signal and arc extinguishment time signal accompanying the opening/closing operation electrically obtained from the current transformer. By accumulating the value obtained by integrating these time differences and the effective value obtained from the current transformer over the arc time, it is possible to detect an abnormality in opening/closing operation or a damaged state of the contact, and to select the appropriate inspection timing. Therefore, it is possible to provide a method for monitoring switching equipment that can achieve both maintenance and economical efficiency of construction.

[Brief explanation of the drawing]

1a, b and 2a, b respectively show the opening and closing operations of the switching device of the present invention, a and b show the current waveform and stroke curve, respectively, and FIGS. 3a,
FIG. 4 is an explanatory diagram showing the mounting position of the sensor section of the present invention, and FIG. 5 is a diagram showing the method for monitoring switching equipment of the present invention. 6 is a diagram showing the characteristics of the accumulation circuit shown in FIG. 5, FIG. 7 is a vertical sectional view showing a general disconnector, FIG. 8 is a circuit diagram showing another embodiment of the present invention, FIGS. 9a, b, and c respectively show FIG. 8, where a is an explanatory view of the operation, b is a perspective view, and c is a front view. 1...Opening/closing mechanism section, 2...Operation rod, 3...
Main shaft, 4... Lever, 7... Movable contact, 8...
Fixed contact, 10, 10a, 10b...Magnet, 11...Sensor, 13...Sensor part, 1
5...Disconnector, 16...Current transformer, 20...Optical sensor, 23...Slit plate, 23a...
...Slit, 30...Monitoring device.

Claims (1)

[Scope of Claims] 1. A current transformer is connected to a switching device that includes a fixed contact, a movable contact, and an operating section that drives a movable section that includes the movable contact, and the current transformer is connected to the operating section that is connected to the operating section. The movable part is provided with a position detection device that detects the opening/closing position of the movable contact of the movable part, and a signal obtained from the position detection device accompanying the opening/closing operation and a signal accompanying the opening/closing operation obtained from the current transformer are provided. A method for monitoring switching equipment, characterized in that the arc time of the switching equipment is measured based on an arc extinction time signal and an arc generation time signal. 2. The method for monitoring switching equipment as set forth in claim 1, wherein the position detection device includes a sensor section provided in a rod section on which an operating section for driving a movable contact is linearly operated. 3. The method for monitoring opening/closing equipment as set forth in claim 1, wherein the position detection device is provided with a sensor section consisting of a disc with a slit and an optical sensor on the operation shaft on which the movable contact and the driving operation section are rotated. . 4. The arc time of switching equipment is determined by detecting the time difference between the moment when the movable contact leaves and the arc extinction time during opening operation, and the time difference between the arc generation time and the moment when the movable contact contacts during closing operation. A method for monitoring switching equipment according to claim 1. 5. Monitoring of switching equipment according to claim 1, which integrates the effective value of the electrical signal obtained by a current transformer over the arcing time of the switching equipment, and accumulates this time-integrated value for each switching operation. Method.