JP2011061892A - Load control unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To dispense with a changeover device for enabling a user to manually operate a changeover to a trial operating mode from a usual operating mode. <P>SOLUTION: A changeover circuit 26 of a load control unit 1 detects open and close of a circuit breaker 7, gives a normal power to a multi-functional protection relay device 5 from a main circuit 3 in a closed-circuit state of the circuit breaker 7, and gives a power for testing to the multi-functional protection relay device 5 in an open-circuit state of the circuit breaker 7. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a load control device having control functions such as power supply to a load, interruption, protection, and monitoring.

  In a load control device (unit device) stored in a closed switchboard used as a control center, by applying a microcomputer, a number of controls such as power supply, interruption, protection, and monitoring for a load (for example, an electric motor) are performed. The thing provided with the function is provided (for example, refer patent document 1).

JP-A-6-105452

  In a closed switchboard having the load control device as described above, the function of the load control device may be tested. Such a test is performed, for example, at the time of manufacturing a closed switchboard or at a maintenance check of the installed closed switchboard.

  Incidentally, in recent years, it has been required to perform the above-described test without pulling out the load control device from the closed switchboard. In order to be able to realize the test without drawing out the load control device, a switching device for shifting from the normal operation mode to the test operation mode is required. Here, the structure provided with such a switching device is demonstrated with reference to FIG. 4, FIG. FIG. 4 is a perspective view schematically showing an external configuration of the load control device including the switching device. FIG. 5 is a diagram schematically showing a circuit configuration of a load control device including a switching device.

  As shown in FIG. 4, the load control device 101 includes a circuit breaker 102 (MCCB: Molded Case Circuit Breaker), an electromagnetic contactor 103 (contactor), a multi-function protective relay device 104 (motor multi-relay), and a switching A device 105 (COS: Change Over Switch) is provided. The front surface of the load control device 101 stored in the closed switchboard is covered with a storage door 106.

  As shown in FIG. 5, the circuit breaker 102 has a main contact 102a and an auxiliary contact 102b. The main contact 102a is provided in a main circuit 108 that supplies AC power from a commercial power source to an electric motor 107 that is a load. In accordance with the magnitude of the main circuit current, the interruption operation (the main contact 102a is opened and the auxiliary contact 102b is closed) is performed. The circuit breaker 102 also includes an operation dial 102c (see FIG. 4), and the user can manually open and close the main contact 102a and close the auxiliary contact 102b by manually operating the operation dial 102c. It is configured.

  The multi-function protection relay device 104 is supplied with a regular power supply from the main circuit 108 via the transformer 109. The multi-function protection relay device 104 has a number of control functions such as power supply, interruption, protection, and monitoring for the electric motor 107, and controls the driving of the electric motor 107 when the start / stop switch 104a is operated. It is supposed to be.

The electromagnetic contactor 103 includes a switch 103b that is controlled to open and close the main circuit 108 in response to the disconnection of the control coil 103a by the multi-function protective relay device 104.
The switching device 105 includes a main switch 105 a and an auxiliary switch 105 b, and the main switch 105 a is provided in a test power supply circuit 110 that supplies a test power supply to the multifunctional protective relay device 104. The switching device 105 includes an operation dial 105c (see FIG. 4), and is configured such that when the user manually operates the operation dial 105c, the main switch 105a is opened and closed and the auxiliary switch 105b is opened and closed. ing.

  When the operation dial 102c of the circuit breaker 102 is operated to the “OFF” side and the main contact 102a is opened and the auxiliary contact 102b is closed, the user switches the operation dial 105c to the test power supply side. The main switch 105a of the switching device 105 is turned on to close the test power supply circuit 110. When the main contact 102a of the circuit breaker 102 is opened, the main circuit 108 is opened. As a result, the supply of AC power from the main circuit 108 to the electric motor 107 and the supply of the regular power supply from the main circuit 108 to the multi-function protective relay device 104 are cut off, and the multi-function type is supplied from the test power circuit 110. A test power supply is supplied to the protection relay device 104.

  With the above operation, the load control device 101 is switched from the normal operation mode in which AC power is supplied from the main circuit 108 to the motor 107 and normal power is supplied to the multi-function protection relay device 104, from the main circuit 108 to the motor 107. Switching to the test operation mode in which the supply of AC power is cut off and the test power is supplied to the multi-function protective relay device 104 is put into a state where the function of the multi-function protective relay device 104 can be tested.

  In the load control device 101, when the switching device 105 is switched to the test power supply side and the test power supply circuit 110 is closed, the auxiliary switch 105b is opened. This prevents the test power from the test power circuit 110 from being supplied to the electric motor 107 via the transformer 109 (reverse induction).

  According to the load control device 101 configured as described above, the user can perform a function test of the multi-function protection relay device 104 by switching to the test operation mode via the switching device 105. However, in the configuration including such a switching device 105, it is necessary to secure an installation space for the switching device 105. Therefore, the load control device 101 is increased in size (upsized), and thus the closed switchboard is increased in size. The installation space of the closed switchboard will be increased. In particular, as shown in FIG. 4, in the configuration including the switching device 105 that is manually operated by the user, the storage door 106 that covers the front surface of the load control device 101 stored in the closed switchboard is connected to the storage door 106 for the switching device 105. The opening 106a must be provided, and such processing is troublesome.

  The present invention has been made in view of the above-described circumstances, and an object thereof is to realize switching from the normal operation mode to the test operation mode with a configuration that eliminates the need for a switching device that is manually operated by the user. An object of the present invention is to provide a load control device capable of

  A load control device according to the present invention includes a main circuit that supplies AC power to a load, and a circuit breaker that is provided in the main circuit so as to perform a cut-off operation according to the magnitude of the main circuit current, and that can be opened and closed manually. A load control means for controlling the load when a normal power is supplied from the main circuit; and detecting the opening / closing of the circuit breaker, and when the circuit breaker is in a closed state, the load control means And a switching means for switching to supply a test power to the load control means when the circuit breaker is in an open circuit state.

  According to the load control device of the present invention, the switching means detects the opening / closing of the circuit breaker, and when the circuit breaker is in a closed state, the load control means is provided with a normal power supply from the main circuit, and the circuit breaker is opened. When in the state, the load control means is switched to supply a test power source. Thereby, it is possible to switch between the normal operation and the test operation with a configuration that eliminates the need for a switching device that is manually operated by the user, and it is possible to realize switching from the normal operation mode to the test operation mode.

1, showing an embodiment of the present invention, is a diagram schematically illustrating a circuit configuration of a load control device. The perspective view which shows roughly the external appearance structure of a closed switchboard An enlarged perspective view schematically showing one unit An enlarged perspective view schematically showing an external configuration of a conventional load control device The figure which shows schematically the circuit structure of the conventional load control apparatus.

Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 3.
FIG. 1 is a diagram schematically showing a circuit configuration of one unit (one unit device) of a load control device stored in a closed switchboard used as a control center. FIG. 2 is a perspective view schematically showing an external configuration of a closed switchboard in which the load control device is stored. FIG. 3 is an enlarged perspective view schematically showing an external configuration of one unit of the load control device.

  As shown in FIG. 2, the closed switchboard sequentially accommodates a plurality of load control devices 1 that are individualized for each unit in the vertical direction, and each load control device 1 includes an electric motor 2 (load) 1, refer to FIG. 1), and control such as power supply, interruption, protection, and monitoring is performed.

As shown in FIG. 1, the load control device 1 includes a main circuit 3, an auxiliary circuit 4, and a multi-function protection relay device 5 (an example of load control means, a motor multi-relay).
The main circuit 3 is provided between a three-phase AC commercial power source 6 composed of an R phase, an S phase, and a T phase and an electric motor 2 that is a load. The main circuit 3 supplies AC power from the commercial power supply 6 to the electric motor 2 and supplies a normal power supply to the multifunctional protective relay device 5. The main circuit 3 includes a main contact 7a of a circuit breaker 7 (MCCB), a main switch 8a of a magnetic contactor 8 (contactor), a current transformer 9, and a zero-phase current transformer 10. Is provided. The current transformer 9 detects a current (main circuit current) flowing through the main circuit 3. The zero phase current transformer 10 detects the zero phase current (ground fault current) of the main circuit 3.

  The circuit breaker 7 is provided in the main circuit 3 so as to perform a breaking operation (a main contact 7a is opened and an auxiliary contact 7b described later is closed) according to the magnitude of the main circuit current. The circuit breaker 7 includes an operation dial 7c (see FIG. 3), and the user can manually open and close the main contact 7a by operating the operation dial 7c. The circuit breaker 7 has an auxiliary contact 7b that opens and closes in conjunction with the opening and closing of the main contact 7a.

  In the main circuit 3, the primary winding 11 a of the step-down transformer 11 is connected between any two phases on the load side (downstream side of the main circuit 3) of the main contact 7 a of the circuit breaker 7. This step-down transformer 11 includes two secondary windings 11b and 11c. Among these, the secondary winding 11b of one system is connected to the DC power supply circuit 5a of the multifunctional protective relay device 5 via the control power supply lines 12 and 13, and the multifunctional protective relay device 5 is driven. Used to generate power. The other secondary winding 11 c of one system is used for the operation of the auxiliary circuit 4 via the normal power supply lines 14 and 15. Note that test control power supply lines 12 ′ and 13 ′ of a test power supply 18 supplied via cables 16 and 17 are connected to the DC power supply circuit 5 a. The cables 16 and 17 function as a communication cable (for example, a communication cable for program writing and rewriting) of the multi-function protection relay device 5 and supply a test power to the multi-function protection relay device 5. It is also connected to test power supply lines 14 'and 15'.

  The multifunctional protective relay device 5 is provided with a switching circuit 26 (one embodiment of switching means). The changeover circuit 26 has a changeover switch 26 a, one fixed contact a connected to the regular power supply line 14, and the other fixed contact b connected to the test power supply line 14 ′ via the safety switch 29. The movable contact c is connected to the power line 30. The common power line 15 and the test power line 15 ′ are connected in common.

  Accordingly, the changeover circuit 26 has a state in which the power supply line 30 is connected to the normal power supply line 14 side and a state in which the power supply line 30 is connected to the test power supply line 14 'side (state shown in FIG. 1). It is designed to switch to.

  An open / close input circuit 26b of the switching circuit 26 is connected between the terminal 25 of the multi-function protection relay device 5 and a common connection point of the regular power supply line 15 and the test power supply line 15 ′. The auxiliary contact 7 b of the circuit breaker 7 is connected between the terminal 25 and the terminal 25. The switching circuit 26 detects the opening / closing of the circuit breaker 7 (auxiliary contact 7b) by the opening / closing input circuit 26b, and switches the changeover switch 26a according to the opening / closing state. That is, when the circuit breaker 7 is in a closed state (main contact 7a is closed and auxiliary contact 7b is open), the changeover circuit 26 sets the changeover switch 26a to the regular power supply line 14 side (contact ca-on). When the circuit breaker 7 is switched (when the main contact 7a is open and the auxiliary contact 7b is closed), the changeover switch 26a is switched to the test power supply line 14 'side (contact cb on). It has become.

  The safety switch 29 of the switching circuit 26 is a normally open switch that is closed by a user's manual operation. Accordingly, the supply of the test power supply 18 to the multi-function protection relay device 5 is enabled when the safety switch 29 is operated and closed. The safety switch 29 can also be provided as an existing switch provided in the multifunctional protective relay device 5.

  In the auxiliary circuit 4, a control coil 8 b of the electromagnetic contactor 8 is connected between the power line 30 and the terminal 19 of the multifunctional protective relay device 5. An auxiliary switch 8 c of the electromagnetic contactor 8 is connected between the power line 30 and the terminal 20 of the multifunctional protective relay device 5. The main switch 8a and the auxiliary switch 8c are normally open switches that close in response to energization of the control coil 8b. The auxiliary switch 8 c outputs an answer back signal for confirming the open / closed state of the main switch 8 a of the electromagnetic contactor 8 to the multi-function protection relay device 5.

  A start switch 22 is connected between the power line 30 and the terminal 21 of the multifunctional protective relay device 5. The start switch 22 is a normally open switch that is closed by a user's manual operation. A stop switch 24 is connected between the power line 30 and the terminal 23 of the multifunctional protective relay device 5. The stop switch 24 is a normally closed switch that is opened by a user's manual operation.

  The multi-function protection relay device 5 includes a ROM, a RAM, and the like centered on a microcomputer, and is based on a load control program stored in a rewritable nonvolatile memory (flash memory) (not shown). Processing such as power interruption (start / stop) to 2 and protection and monitoring (normal operation mode) is performed. The multi-function protective relay device 5 is configured to be able to execute a test operation mode to be described later based on a test operation program stored in a nonvolatile memory.

  The multi-function protection relay device 5 includes a determination circuit 27. The determination circuit 27 disconnects the control coil 8b of the electromagnetic contactor 8 when the main contact 7a of the circuit breaker 7 is closed and the auxiliary contact 7b is opened during the test operation. The determination circuit 27 functions as an overcurrent determination circuit that detects the overcurrent of the electric motor 2 based on the output signal of the current transformer 9 and the electric motor based on the output signal of the zero-phase current transformer 10. 2 has a function as an electric leakage determination circuit for detecting electric leakage.

  In addition, the multi-function type protective relay device 5 is a current detection circuit (not shown) for A / D converting and outputting each output signal of the current transformer 9 and the zero-phase current transformer 10, and energizing the control coil 8b and the like. Input circuit (not shown) for inputting the state, the open / close state of various contacts, the load control state, etc., and an output circuit for outputting signals for changing the energized state of the control coil 8b and the various contact open / close states (Not shown). The load control state refers to the operation state of the electric motor 2 (for example, the start / stop state of the electric motor 2, the rotational speed, acceleration / deceleration, etc.), the control coil 8b in the load control device 1 for creating the operation state, and the like. Excitation state, open / close state of various contacts.

  In addition, as shown in FIG. 3, the storage door 28 which opens and closes this is provided in the front opening part of each unit room of a closed switchboard. An opening 28a is formed in the storage door 28 so that the operation dial 7c of the circuit breaker 7 can be operated from the outside. In addition, the storage door 28 is formed with an opening 28b for exposing the operation display unit on the front surface of the multifunction protective relay device 5 to the outside.

Next, the operation of the load control device 1 will be described.
First, the operation of the load control device 1 during normal operation (operation in the normal operation mode) will be described.
During normal operation, the main contact 7a of the circuit breaker 7 is closed. Further, the auxiliary contact 7b is opened in response to the closing of the main contact 7a. Therefore, the changeover circuit 26 switches the changeover switch 26a to the regular power supply line 14 side (contact c-a on).

  In this state, when the user operates the start switch 22 of the multifunction protection relay device 5, the multifunction protection relay device 5 energizes the control coil 8 b of the electromagnetic contactor 8 by energizing it. As a result, the main switch 8a of the electromagnetic contactor 8 is closed, AC power from the commercial power source 6 is supplied from the main circuit 3 to the electric motor 2, and the electric motor 2 is started. Further, AC power from the commercial power source 6 is supplied from the main circuit 3 through the step-down transformer 11 to the multi-function protection relay device 5 as a normal power source, and the multi-function protection relay device 5 controls the driving of the motor 2. To do.

  At this time, the auxiliary switch 8c is closed in response to the closing of the main switch 8a of the electromagnetic contactor 8, an answer back signal is given to the multi-function protective relay device 5, and a self-holding circuit is provided in the auxiliary circuit 4. It is supposed to be formed. Thereby, even if the start switch 22 is returned to the OFF state, the electric power continues to be supplied from the commercial power source 6 to the electric motor 2.

  On the other hand, when the user operates the stop switch 24 of the multifunction protective relay device 5, the self-holding circuit formed in the auxiliary circuit 4 is released. Thereby, the main switch 8a of the electromagnetic contactor 8 is opened, the supply of electric power from the commercial power source 6 to the electric motor 2 is cut off, and the electric motor 2 is stopped.

  Next, the operation of the load control device 1 during the test operation (operation in the test operation mode) will be described. This test operation is performed without pulling out the load control device 1 from the closed switchboard.

  During the test operation, the user manually operates the operation dial 7c of the circuit breaker 7 to open the main contact 7a. Thereby, the supply of AC power from the commercial power source 6 to the electric motor 2 is interrupted. Further, the auxiliary contact 7b is closed in response to the opening of the main contact 7a. Therefore, the changeover circuit 26 switches the changeover switch 26a to the test power supply line 14 'side (contact cb on). Thereby, the supply of the regular power supply from the commercial power supply 6 to the multifunctional protective relay device 5 through the step-down transformer 11 is cut off. Further, when the user operates the safety switch 29, the test power is supplied to the multi-function protection relay device 5 through the test power lines 14 ′ and 15 ′. The multi-function protection relay device 5 performs the test via the test control power supply lines 12 'and 13' when the changeover switch 26a is switched to the test power supply line 14 'side (contact cb on). The power supply is supplied to the DC power supply circuit 5a.

  In this state, when the user operates the start switch 22 of the multi-function protection relay device 5, the multi-function protection relay device 5 energizes and energizes the control coil 8b of the electromagnetic contactor 8, and turns the main switch 8a on. Close. The user can perform an operation test of the electromagnetic contactor 8 by checking whether or not the main switch 8a of the electromagnetic contactor 8 is closed according to the operation of the start switch 22. In this test operation mode, since the supply of AC power from the commercial power source 6 to the electric motor 2 is interrupted, the electric motor 2 does not start even if the main switch 8a of the electromagnetic contactor 8 is closed. At this time, a self-holding circuit is formed in the auxiliary circuit 4. Thereby, unless the user operates the stop switch 24, the state of the test operation described above (the state in which the control coil 8b of the electromagnetic contactor 8 is excited and the main switch 8a is closed) is maintained.

  On the other hand, when the user operates the stop switch 24 of the multifunction protective relay device 5, the self-holding circuit formed in the auxiliary circuit 4 is released. Thereby, the excitation of the control coil 8b of the electromagnetic contactor 8 is released, and the main switch 8a is opened. The user can perform an operation test of the electromagnetic contactor 8 by confirming whether or not the main switch 8a of the electromagnetic contactor 8 is opened according to the operation of the stop switch 24.

Next, the operation of the load control device 1 when the main contact 7a of the circuit breaker 7 is accidentally closed during the test operation described above will be described.
The determination circuit 27 of the multi-function protective relay device 5 monitors the open / close state of the circuit breaker 7 during the test operation (open / close state of the main contact 7a and the auxiliary contact 7b) via the open / close input circuit 26b. ing. When the main contact 7a of the circuit breaker 7 is closed during the test operation, the determination circuit 27 controls the main switch 8a of the electromagnetic contactor 8 so as to open the main circuit 3. . In other words, when the determination circuit 27 of the multi-function protective relay device 5 detects the closing of the main contact 7a of the circuit breaker 7 during the test operation, it immediately cuts off the energization to the control coil 8b of the electromagnetic contactor 8. The excited state is released and the main switch 8a is opened. As a result, the main circuit 3 is opened.

  As described above, according to the present embodiment, the switching circuit 26 detects the opening / closing of the circuit breaker 7 via the switching input circuit 26b, and when the circuit breaker 7 is in a closed state, the multi-function protection The changeover switch 26a is switched so that the relay circuit 5 is supplied with the normal power from the main circuit 3. When the circuit breaker 7 is in the open state, the changeover switch 26a is switched so as to supply the test power to the multi-function protective relay apparatus 5. . As a result, it is possible to switch between the normal operation mode and the test operation mode from the normal operation mode to the test operation mode with a configuration that eliminates the need for a conventional switching device (see FIGS. 4 and 5) that is manually operated by the user. Switching to can be realized.

  Further, since the conventional switching device is not required, it is not necessary to secure an installation space for the switching device, and the load control device 1 is enlarged (upsized), and the closed switchboard is enlarged, and the closed switchboard is installed. An increase in space can be suppressed.

  Further, it is not necessary to provide an opening for the switching device in the storage door 28 (see FIGS. 2 and 3) covering the front surface of the load control device 1 stored in the closed switchboard, and processing for providing such an opening is not necessary. Save time and effort. Further, the burden of wiring work for the switching device can be saved.

  The load control device 1 also includes a safety switch 29 that enables the test power supply to be supplied to the multifunctional protective relay device 5 by the switching circuit 26. Thus, the test operation mode can be executed after confirming the user's intention (the safety switch 29 has been operated in an attempt to execute the test operation mode), and the test operation mode can be safely shifted (switched). Can do.

In addition, since the test operation is automatically executed in response to the operation of the safety switch 29 after the transition to the test operation mode, the test time can be shortened.
Further, the multi-function protective relay device 5 is provided when the circuit breaker 7 is closed in a state where the switching circuit 26 is switched to supply test power to the multi-function protective relay device 5. Controls the magnetic contactor 8 (main switch 8a) so as to open the main circuit 3. Thereby, even if the circuit breaker 7 is accidentally closed during the test operation and AC power is supplied from the main circuit 3 to the electric motor 2, the multi-function protective relay device 5 is connected to the electromagnetic contactor 8. Since the main circuit 3 is instantaneously interrupted by the (main switch 8a), it is possible to prevent the electric motor 2 from operating unnecessarily and to ensure the safety of the operator.

  Further, since the test power supply is supplied to the multi-function protective relay device 5 and the DC power supply circuit 5a using the cables 16 and 17 functioning as communication cables, the test power supply circuit 110 of the conventional configuration and the auxiliary power supply are provided. The switch 105b and wiring associated therewith can be eliminated, and the configuration can be simplified.

In addition, this invention is not limited only to the above-mentioned one Embodiment, For example, it can deform | transform or expand as follows.
The function to be tested of the multi-function type protective relay device 5 is not limited to the test of the electromagnetic contactor 8 shown in the above-described embodiment. An operation test of an overcurrent determination circuit for determination, an operation test of a leakage determination circuit for determining leakage based on a detection value of the zero-phase current transformer 10, an operation test of an alarm device for notifying abnormality can be performed.

Various tests can be performed by appropriately changing (rewriting) the contents of the test operation program stored in the nonvolatile memory.
The load is not limited to the electric motor 2 (motor), and may be an electromagnetic solenoid, for example.
The safety switch 29 may be provided as an existing switch provided in the multi-function protection relay device 5 or may be provided as a new switch.

  In the drawings, 1 is a load control device, 2 is a motor (load), 3 is a main circuit, 5 is a multi-function protective relay device (load control means), 7 is a circuit breaker, 8 is an electromagnetic contactor, and 26 is a switch. A circuit (switching means) 29 is a safety switch.

Claims (3)

A main circuit for supplying AC power to the load;
A circuit breaker that is provided in this main circuit so as to perform a breaking operation according to the magnitude of the main circuit current, and that can be opened and closed manually.
A load control means for controlling the load by receiving a normal power supply from the main circuit;
When the circuit breaker is detected to be open / closed, when the circuit breaker is in a closed state, the load control means is supplied with a normal power supply from the main circuit, and when the circuit breaker is in an open state, the load control means is tested. A load control device comprising switching means for switching so as to provide a power supply for the vehicle.   2. The load control device according to claim 1, further comprising a safety switch that enables supply of test power to the load control means by the switching means. An electromagnetic contactor controlled to open and close the main circuit by the load control means;
The load control means includes
When the circuit breaker is closed while the switching means is switched to supply the test power to the load control means, the electromagnetic contactor opens the main circuit. The load control device according to claim 1 or 2, wherein the load control device is controlled.

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