JP2647148B2 - Operation monitoring device for power switch - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Use) The present invention relates to an operation monitoring device of a power switch provided with a non-contact type proximity sensor for detecting and monitoring an open / close operation state of an open / close unit. About.

(Prior art) Circuit breakers generally used as power switches are:
An auxiliary switch is provided in the operation mechanism in order to display the opening / closing operation state of the blocking unit and measure the opening / closing operation time. This auxiliary switch has an a-contact and a b-contact that open and close in conjunction with the opening and closing operation of the operation mechanism of the circuit breaker.

However, the operation of the auxiliary switch is uncertain due to abrasion of the contacts and adhesion of dust due to an increase in the cumulative number of switching operations of the circuit breaker because the a-contact and the b-contact of the mechanical contacts are operation sources. was there.

Therefore, recently, with the development of a monitoring system for the purpose of predicting the abnormality of a breaker, a non-contact proximity switch was used instead of the conventional auxiliary switch to detect the open / close operation state of the breaker. Sensors have been used. Some of the non-contact proximity sensors use, for example, high-frequency oscillation, and utilize the fact that when a metal that is a detection object approaches the oscillation coil, oscillation stops due to a change in L and a change in loss in the sensor circuit. It is.

Thus, the non-contact proximity sensor is provided to face a metal flange which is an object to be detected and is provided at a connection portion between the operation rod for moving the movable electrode of the circuit breaker and the operation mechanism. An open position and a closed position are detected in an open state and a closed state, and an open position signal and a closed position signal are issued, respectively.

(Problems to be Solved by the Invention) In these conventional switching operation monitoring devices using a non-contact proximity sensor, the proximity sensor is provided in an operation mechanism of a circuit breaker, and the output is usually provided by a cable such as a twisted pair wire. The signal is transmitted to the relay panel housing the sensor receiver and the measuring unit. However, when applied to a circuit breaker of a high voltage class, the following various problems are caused.

In other words, when the circuit breaker operates in the charged state of the main circuit, a discharge occurs at the main contact of the circuit breaker, and a high-frequency surge due to this reaches the operation mechanism through each part of the circuit breaker, so that the contactless proximity sensor is There is a risk of malfunction.

An object of the present invention is to provide a power switch operation monitoring device which is applied to a high-voltage class power switch and has high surge resistance and high reliability.

[Means for Solving the Problems] The operation monitoring apparatus for a power switch of the present invention is provided so as to face a metal flange provided on an operation rod of the power switch, and an input position of the metal flange. And a contactless proximity sensor for detecting the trip position. A portion of the cable transmitting the detection signal of the contactless proximity sensor that is extremely close to the contactless proximity sensor is set as a relay point. A surge absorbing impedance exhibiting a low impedance with respect to a high frequency is connected between the cables and between the cable core wire and the ground.

(Operation) In the present invention, when a surge occurs during the opening / closing operation of the power switch, the surge is absorbed by the surge absorbing impedance between the cable cores and the ground, and the distance between the proximity sensor housing and the cable core is changed. The occurrence of a potential difference therebetween is prevented, and the intrusion into the proximity sensor is prevented.

(Embodiment) The present invention will be described below with reference to the embodiments shown in FIGS. 1, 2, 3, and 4. FIG. In the embodiment shown in FIG. 1, a puffer type gas circuit breaker is shown as the power switch 1. That is, the puffer type gas circuit breaker 1
The fixed electrode 3 and the movable electrode 4 are arranged so as to be relatively movable in a closed case 2 containing SF ₆ gas, and both electrodes 3 and 3 are formed by a puffer mechanism 5 which is attached to the movable electrode 4.
At the time of opening and closing operation of 4, the compressed insulating gas is blown to extinguish the arc.

The movable electrode 4 of the puffer type gas circuit breaker 1 is opened / closed by the vertical movement of the operating piston 9 of the operating mechanism 8 via the insulating rod 6 and the operating rod 7. The operating piston 9 of the operating mechanism 8 is moved downward by the opening of the hydraulic system tripping valve 12 having the accumulator 10 and the oil pump 11 to trip the movable electrode 4 from the fixed electrode 3 and open the closing valve 13. To move the movable electrode 4 to the fixed electrode 3.

In this type of power switch, an operation monitoring device is attached for the purpose of predicting an abnormality of the cutoff unit and measuring the switching operation time. Therefore, in the present invention, the operation monitoring device 14 is provided in the operation mechanism 8 as shown in FIG. The operation monitoring device 14 includes a metal flange 16 in the monitoring case 15 for connecting the operation rod 7 and the piston rod of the operation piston 9 and two non-contact proximity sensors 17a, 17
and a proximity sensor mounting plate 18 to which b is mounted.

As shown in detail in FIG. 2, the two non-contact proximity sensors 17a and 17b are mounted on the proximity sensor mounting plate 18 facing the metal flange 16 as a detection object. The upper non-contact proximity sensor 17a detects the closed state position of the movable electrode 4, and the lower non-contact proximity sensor 17b detects the trip state position of the movable electrode 4. Double Proximity Sensor 17
The detection signals of a and 17b are transmitted to the relay board via cables 19a and 19b such as twisted pair wires, respectively, and become input signals to the sensor receiver and the measurement unit in the relay board.

The operation monitoring device 14 shown in FIGS.
In the arrangement configuration of the non-contact proximity sensors 17a and 17b, when the power switch 1 opens and closes during charging of the main circuit, the proximity sensors 17a and 17b may malfunction. This is because when a discharge occurs between the fixed electrode 3 and the movable electrode 4 of the power switch 1, a sudden potential change occurs in the grounding system including the closed case 2 and the monitoring case 15.

On the other hand, since the core wires of the output cables 19a and 19b of the output cables 19a and 19b of the proximity sensors 17a and 17b are insulated from the grounding system of the power switch, they have the same potential as this core wire and the monitoring case 15. A potential difference occurs momentarily between the proximity sensors 17a and 17b and the sensor case. This potential difference can reach hundreds to thousands of volts in a power switch of a high voltage class of 300 kV or more.

The principle of the proximity sensors 17a and 17b is that a high-frequency oscillation circuit is housed inside the proximity sensor and the high-frequency oscillation is turned on and off by a change in the electromagnetic mutual induction coefficient due to the approach of a detection object such as iron. . Thus, the proximity sensor 17a,
Since an electronic circuit is housed inside 17b, if a potential difference of several hundred volts or more as described above occurs between the sensor case and the core wires of the cables 19a and 19b during operation of the power switch 1, malfunction naturally occurs. Will do. As a measure for preventing this malfunction, it is conceivable to prevent the above-mentioned potential difference from occurring.

Therefore, in the power switch operation monitoring device according to the present invention, as shown in FIG.
b is attached to the sensor mounting plate 18 and attached to the monitoring case 15, but the output cables 19a and 19b of both the proximity sensors 17a and 17b are relayed near the proximity sensors 17a and 17b, and the core wire 19a is provided. ', 19b' and core 19
It is characterized in that surge absorbing impedances 20 and 21 are respectively connected and arranged between a ', 19b' and ground, that is, the mounting plate 18.

By connecting the proximity sensor mounting plate 18 between the core wires 19a ', 19b' of the cables 19a, 19b of the proximity sensors 17a, 17b and the proximity sensor mounting plate 18 in this manner, the ground is passed through the impedance 21 at high frequency. The proximity sensor 17a, 17
It is possible to prevent a potential difference from occurring between the housing b and the cable cores 19a 'and 19b'.

When the power switch 1 operates, the cable core 19
High frequency surge is induced between a 'and 19b'. On the other hand, if the surge absorbing impedance 20 is arranged between the cable cores 19a 'and 19b' very close to the proximity sensors 17a and 17b, the cable cores 19a 'and 19
It is also possible to prevent surges that travel between b ′ and enter the proximity sensors 17a and 17b.

For such surge suppression, the proximity sensors 17a, 17a
The length of the cable from b to the point where the surge absorbing impedance 21 is attached becomes a problem. If this cable is long, the inductance of the cable itself will increase,
Since a surge is induced in the cable itself between the surge absorbing impedances 21, a sufficient countermeasure effect cannot be expected.

Therefore, in the embodiment shown in FIG. 3, it is preferable to relay the cables 19a and 19b at the proximity sensor mounting plate 18, attach a surge absorbing impedance 21 to this location, and connect the ground to the proximity sensor mounting plate 18. The proximity sensors 17a and 17b can be easily attached, the distance of the ground connection can be made short, and the workability can be improved.

Further, in another embodiment shown in FIG. 4, both the non-contact proximity sensors 17a and 17b are mounted on a mounting plate 18, and the mounting plate 18 is fixed to the monitoring case 15 via an insulating washer 25. It is a feature.

It is said that the level of the induced surge generated during the switching operation of the power switch 1 of the 500 kV class is about several tens kV.
Therefore, an insulation washer with a creepage distance of about 10 mm
If 25 is used, it is possible to prevent such a high voltage surge from being directly applied between the mounting plate 18 and the containers of the proximity sensors 17a and 17b.

In the embodiment shown in FIG. 4, the mounting plate 18 and the cable 1 of each non-contact proximity sensor 17a, 17b are also connected as shown in FIG.
A surge absorbing impedance 21 is connected between core wires 19a 'and 19b' of 9a and 19b, and a surge absorbing impedance 20 is connected between both core wires 19a 'and 19b'. Further, if the proximity sensor mounting plate 18 is made of an insulating material, the insulating washer 25 may not be used, but in this case, the ground wire of the surge absorbing impedance 21 must be long, and the It is necessary to consider that guidance may be performed.

[Effects of the Invention] As described above, in the present invention, a non-contact proximity sensor for detecting an open position and a closed position is provided in relation to an operation mechanism of a power switch, and the proximity sensor is provided near the non-contact proximity sensor. By taking measures against surges on the cable core, there is an advantage that inexpensive and highly reliable switch operation monitoring is performed.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing the entire operation monitoring apparatus for a power switch of the present invention, FIG. 2 is an enlarged cross-sectional view showing the operation monitoring apparatus section, and FIG. 3 is a front view of the operation monitoring apparatus section. Figure, 4th
The figure is a sectional view showing another embodiment of the operation monitoring device of the present invention. DESCRIPTION OF SYMBOLS 1 ... Switch for electric power 2 ... Sealing case 3 ... Fixed electrode 4 ... Movable electrode 5 ... Puffer mechanism 7 ... Operation rod 8 ... Operation mechanism 9 ... Operation piston 14 ... Operation monitoring device 15 ... … Monitoring case 16… Metal flange (detection object) 17a, 17b… Non-contact proximity sensor 18… Proximity sensor mounting plate 19a, 19b… Cable 19a ′, 19b ′… Cable core 20,21… Surge absorption Impedance 25 …… Insulated washer

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Isao Kamada, Inventor 2-1 Ukishima-cho, Kawasaki-ku, Kawasaki-shi, Kanagawa Prefecture Inside the Toshiba Hamakawasaki Plant (72) Inventor Junichi Nagata 66-2, Horikawa-cho, Sachi-ku, Kawasaki-shi, Kanagawa In Toshiba Engineering Corporation (56) References Japanese Utility Model 58-195932 (JP, U) Japanese Utility Model 57-150906 (JP, U) Japanese Utility Model 63-70235 (JP, U) Japanese Utility Model 56-82677 (JP, U) JP, U)

Claims (2)

(57) [Claims] 1. A contactless proximity sensor which is provided opposite to a metal flange provided on an operation rod of a power switch and detects a closing position and a tripping position of the metal flange. For a surge absorption device that has a low impedance at high frequencies between the cable cores of this relay point and between the cable core and the ground, as a relay point at a point very close to the contactless proximity sensor of the cable that transmits the detection signal. An operation monitoring device for a power switch, wherein an impedance is connected. 2. The operation monitoring device for a power switch according to claim 1, wherein a proximity sensor mounting plate on which the non-contact proximity sensor is mounted is fixed to an operation mechanism via an insulator.