JPS5834516A - Safety device for bypass switch - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] The present invention is applicable to nuclear power plants, etc.
This invention relates to a bypass switch that is installed for testing purposes in an electrical system that controls the operation of an emergency stop device in a plant that is made up of a large number of devices.

Emergency shutdown devices for plants generally have a structure that detects the status of each device that makes up the plant, and if even one of the detected signals exceeds a specified range, an emergency shutdown operation is performed. Normally excited circuits are often used to achieve the above objectives.

FIG. 1 shows a scram logic circuit for a nuclear reactor emergency shutdown system as an example of the above-mentioned normally excitation circuit.

22.22 is a scram signal output relay, 22a is the same contact, 23a is a scram logic circuit reset signal contact, 23b
is a self-holding contact. The output relay part A configured as above and a large number of scram signal contacts 21, 21...
・The control signal part B formed by connecting in series the power supply (
AC120V).

The above scram signal contacts 21, 21... have a structure that opens when the various conditions of each component of the nuclear power plant (e.g., temperature, pressure, radiation output, etc.) exceed specified values. . Multiple scram signal contacts 21.
When one of the conditions corresponding to 21... exceeds a specified value and one of the scram signal contacts 21 is opened, the scram signal output relay 22φ becomes non-energized and the scram signal output relay contact 22a closes. emergency shutdown of the reactor is performed.

Scram signal contact 2 in the above nuclear power plant
In an emergency stop device control system equipped with a signal contact for emergency stop as in No. 1, when testing the operation of the signal contact while the plant continues to operate, proceed as follows. For example, when performing an operation test of the scram signal contact 21 at the top of FIG. 1, the jumper wire 24 is temporarily connected in parallel with the scram signal contact in advance, and then the operation test of the scram signal contact is performed. When the operation test is performed in this way, even if the scram signal contact is opened, the jumper wire 24 maintains the continuity of the control signal part B, so the scram signal output relay 22 does not become de-energized, and therefore the emergency stop device is activated. It doesn't work. However, the method of temporarily connecting the jumper wires 24 as in the above example requires a high level of knowledge and skill, and furthermore, there is a possibility of making a connection error.

In order to obtain the same effect without the risk of connecting the jumper wire incorrectly, a bypass switch should be connected in parallel with the scram signal contact 21 in advance, and the bypass switch should be closed when testing the operation of the scram signal contact. can also be considered. FIG. 2 shows a logic circuit in which a bypass switch 5 is connected in parallel to a plurality of scram signal contacts 21 via a connector fixed part 15a and a movable part 15b.

As described above, when testing the operation of a signal contact for emergency stop by short-circuiting it with a jumper wire or a bypass switch, there is a risk of making the following serious human error. That is, forgetting to remove the jumper wire 24 temporarily connected for an operation test after the test is completed, or
Alternatively, if the user forgets to turn off the bypass switch 5 that was turned on for the operation test after the test is completed, the signal contact 21 remains short-circuited. Therefore, even if an abnormality occurs in the device corresponding to the signal contact 21 and the signal contact 21 opens, the output relay part A does not operate.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a safety device for a bypass switch that is free from the risk of leaving a signal contact in a short-circuited state after the test is completed due to a human operational error during an operation test of the signal contact. It is.

In order to achieve the above object, the present invention provides manual operation members such as operation levers or operation buttons of the bypass switch (hereinafter referred to as operation levers) in a test bypass switch installed in an emergency stop device control system of plants. and a means for switching the above-mentioned bypass switch to the OFF state, and the above-mentioned door and switch switching means are interlocked so that the switch switching operation is stopped when the door is open, and when the door is closed. The present invention is characterized in that the bypass switch is forcibly held in the OFF state when the door is closed by activating the switch switching means.

Next, one embodiment of the present invention will be described with reference to FIGS. 3 and 4.

The bypass switch storage box 1 is attached to the control panel surface plate 10.
Attach to. 3 is a mounting screw. In this bypass switch storage box 1, the above-mentioned bypass switches 5, 5...
・Arrange and install.

a manual operation lever 5a of the bypass switch 5.5;
A lid 2 is provided to cover the bypass switch storage box 5a, and the bypass switch storage box 1 is secured with a mounting screw 4゜4 and a lock key 12.
Attach it to the front of the Thereby, the lid 2 can be opened and closed only by a person who has a key compatible with the lock key 12.

7 is a transparent plate fitted into the center of the lid 2.

Attach presser bar support plates 8, 8 perpendicularly to the opening lid 2 on both sides of the inside of the lid 2, and suspend the bypass switch operation lever presser bar 6°6 between the support plates 8°80. Pass and stick. The mounting position of the above operating lever holding bar 6.6 is set as follows.

That is, the lid 2 is attached to the front of the bypass switch storage box 1, and the operating levers 5a of the bypass switches 5,
5a, the operating lever holding bar 6.6 comes into contact with the operating levers 5a, 5a in an oblique position, and when the operating levers 5a, 5a are in the ON side, it is turned to the OFF side. Push.

As a result, the operating lever 5a of the bypass switch 5.5
, 5a are in the OFF position, the operating lever presser bar 6 does not function separately even if the lid 2 is attached, but when one or more of the operating levers 5a, 5a is in the ON position, By attaching the lid 2, the operating lever 5a is switched to the OFF position.

As shown in Fig. 4, a limit switch 11 is provided that is pressed when the lid 2 is attached, and wired so that an indicator lamp (not shown) lights up when the lid 2 is open. do.

Furthermore, the minimum necessary function of the above-mentioned bypass switch 5 is a single-pole, single-throw switch function as shown in the logic circuit of FIG. 2, but the bypass switch 5 in this embodiment uses a two-pole, single-throw switch. The wiring is such that one set of electrical contacts performs the bypass switch function, and another set of electrical contacts lights up a pilot lamp (not shown) provided for each bypass switch.

The bypass switch safety device of this embodiment is configured as described above, and during normal operation of the reactor, the bypass switches 5, 5
There is no risk of turning OFF, attaching the lid 2, operating the bypass switch, and covering the bars 5a, 5a. When the engineer in charge with the key opens the lid 2, the indicator lamp lights up, and when the bypass switch is turned on, the pilot lamp lights up.

Then, when the engineer in charge opens the lid 2, the bypass switches 5, 5, . . . can be freely turned on and off. After performing the required switch operations in this state and completing the signal contact operation test, it goes without saying that the bypass switch 5 that was turned ON should be restored to the OFF state, but if the bypass switch 5 is turned OFF, Even if you forget to close the lid 2, the operating lever holding bar 6 comes into contact with the operating lever 5a of the bypass switch 5 and pushes it to the OFF side, so that the bypass switch is returned to the OFF state. Then, while the lid 2 is closed, the bypass switch 5. Death... is forcibly kept in the OFF state.

Moreover, since the indicator lamp lights up while the lid 2 is open, persons other than the technician operating the bypass switch can also know that the signal contact is undergoing an operation test. It is also possible to know which signal contact is being tested by lighting the pilot lamp. By turning on the indicator lamp, the mistake of the test engineer forgetting to close the lid 2 is also prevented.

FIG. 5 shows an embodiment different from the above, in which the lid 2 is attached to the front of the storage box 1 so that it can be opened and closed by a hinge 14, and the lid 2 is attached to the front of the storage box 1 by the arrow C
When the lid is closed, the operating levers 5a, 5a of the bypass switches 5, 5 are covered.

An operating lever holding lever 25 is provided corresponding to the operating lever 5a of each bypass switch 5, and is pivotably supported by a fulcrum pin 25a so as to be freely tiltable. When the operating lever holding lever 25 is tilted upward as shown by the broken line, the operating lever 5a
When the operating lever 5a is moved away from the main body to allow the operating lever 5a to operate freely, and when the operating lever 5a is tilted downward as shown by the solid line, the operating lever 5a
The structure is such that it comes into contact with and pushes it to the OFF side. The opening/closing operation of the lid 2 and the operation lever presser lever are performed via an interlocking arm 13a fixed to the lid 2, links 13b and 13C pin-coupled to this, and an interlocking pin "3C+ + 13Cr" fixed to the link 13C. The vertical tilting movement of 25 is linked.

Specifically, the tip of the interlocking arm 13a and the left end of the link 13b are rotatably connected with a pin, and the link 13b is moved while sliding the slot 13b+ bored therein against the guide pin 13d. It is.

When the lid 2 is opened in the direction of the arrow and reaches the position shown by the broken line,
The link 13b is pulled to the lower left and is in the position shown by the broken line, and the link 13C pin-coupled to this is the fulcrum pin 13.
e and slot 13f, and is raised while tilting to the position shown by the broken line.

As a result, the interlocking pin 13C fixed to the link 13C
-□ l 13 c-, tilts the operating lever presser lever 25 upward to the broken line position, and releases the operating lever 5a of the bypass switch 5.

When the lid 2 is closed, the interlock 7-
The pins 13a, +7/13b, and IJ/13C are at the positions indicated by solid lines, and the interlocking pins 13C-, 13C are in the positions shown by the solid lines.
3 c-, operating lever presser L/bar 2 s,
25 downward as shown by the solid line, and push down the operating levers 5a, 5a of the bypass switches 5, 5 to turn the bypass switches 5, 5, . . . OFF.

Next, a different embodiment from the above will be described with reference to FIG.

Bypass switch storage box 1% Lid 2, mounting screws 4
, a bypass switch 5, a transparent plate 7, and a hinge 14, which are the same structural members as those in the embodiment shown in FIG.

An interlocking arm 13a fixed to the lid 2, a link 13b pivotally attached to the interlocking arm, and a link 1 pivotally attached to the link.
3C1 The fulcrum pin 13e and slot 13f guiding the upper end of the link 13C are structural members similar to those in the embodiment shown in FIG.

As a result, when the lid 2 is in the closed door position shown by the solid line, the link 13C is in the position shown by the solid line due to the same operation as in the previous example, and when the lid 2 is in the open position shown by the broken line, the link 13C is It is tilted into the posture shown by the broken line.

This is the connector fixing part explained in connection with the logic circuit in FIG. 2 on page 15a. This is fixed to the bypass switch storage box 1. 15b is a connector movable part. This is guided by guide rails 17 so as to slide in the directions of arrows G and H.

Then, the above-mentioned connector I lid movable part 15b and link 13
C is pivoted with an interlocking pin 26. As a result, the link 13C tilts in the direction of the arrow J as the lid 2 opens and closes in the directions of the arrows C and D, and the connector movable portion 15b is moved in the directions of the arrows G and H.

In this example, when the lid 2 is opened, the connector movable part 15b is moved in the direction of arrow H and the connector fixed part 158KW is mated, so that the bypass switch 5.5 is
a, signal contact port M (not shown in this figure) via 15b
conducts to. When the lid 2 is closed after completing the signal contact operation test, the connector movable part 15b is moved in the direction of arrow G and removed from the connector fixed part 15a, so that the bypass switches 5, 5 are connected to the signal contact circuit. conduction is cut off, and the bypass circuit is forcibly turned off.

As explained above, the present invention provides a bypass switch for signal contact testing provided in an emergency stop device control system for plants, and provides a door that covers the operation levers of the bypass switch, and also enables the bypass switch to be turned off.
A means for switching to the F state is provided, and the door and the switch switching means are interlocked so that the switch switching means is inactive in the door open state, and the switch switching means is activated in conjunction with the door closing operation to close the door. By forcibly holding the bypass switch in the OFF state in such a state, there is no risk of leaving the signal contact in a short-circuited state after the test is completed due to human error during the operation test of the signal contact.

[Brief explanation of drawings]

Figure 1 is a scram logic circuit diagram of the reactor emergency shutdown system, Figure 2
The figure is a scram logic circuit diagram of a nuclear reactor emergency shutdown system equipped with a bypass switch function. 3 and 4 show a safety device for a bypass switch according to an embodiment of the present invention,
FIG. 3 is a partially sectional front view, and FIG. 4 is a sectional side view. 5 and 6 are cross-sectional side views of a bias switch safety device in different embodiments from those described above, respectively. 1...Bijas switch storage box, 2...lid,
3゜4...Mounting screw, 5...Bypass switch, 5
a... Same operating lever, 6... Operating lever holding bar,
7... Transparent plate, 8... Presser bar support plate, 1o...
Control panel surface plate, 11...Limit switch, 12...
・Lock key, 13a... Interlocking arm, 13b, 1
3C... Link, 13 b-,... Slot, 13 d.
...Guide pin, 13e...Fully pin, 13f...Slot hole, 14...Hinge, 15a...Connector fixing part,
15b... Connector movable part, 17... Guide rail, 21... Scram signal contact, 22... Scram signal output relay, 22a... Scram signal output relay contact, 23a... Scram logic circuit reset signal contact,
23b... Self-holding contact, 24... Jumper wire,
25...Operating lever Presser lever Fig. 1 2 Fig. 3 Fig. 5 - 11 Surface cover ° - Operation III * Power making method Aoman Fig. 6

Claims (1)

[Claims] 1. A bypass switch for signal contact testing installed in a control system for an emergency stop device in plants is provided with a door that covers the operating levers of the bypass switch and means for switching the bypass switch to the OFF state, and The switch switching means is interlocked with the switch switching means to block the switch switching means when the door is open, and the switch switching means is activated when the door is closed, and the bypass switch is forced when the door is closed. OF'
A bypass switch safety device characterized by doing something to maintain the F state.