JPH03226929A - Protector for breaker - Google Patents

Abstract

PURPOSE:To prevent any short circuit of a motor circuit due to generation of chattering or the like of a switch of a switch mechanism by starting to store energy of an operating spring upon completion of a closing operation or a trip free operation. CONSTITUTION:There are provided a closing drive circuit 18 for energizing a first switching element 16a for a predetermined period in response to a closing command, and a spring energy storing drive circuit 19 for energizing a second switching element 16b after a preset time delay since an operation spring starts to evolve energy and for turning off the second switching element 16b when the energization time exceeds a given time There is also provided an interlock circuit 22 for forcibly keeping an output from the closing drive circuit at off- position during the energization of the second switching element 16b. Consequently, a closing operation during incomplete energy storage of the spring can be prevented, and the energy storing of the operating spring can be performed upon completion of the closing operation. Therefore, any short circuit of a motor circuit due to generation of chattering or the like of a switch of a switch mechanism can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a circuit breaker protection device using an electric spring operation method.

(Prior art) There are various operating methods for circuit breakers, switches, etc. that have been used in the past, such as an electric spring operating method, a manual operating method, and a solenoid operating method. The electric spring operation method has become mainstream in recent years because it does not require its own power supply equipment, provides stable operating force, and is small and lightweight.

This electric spring operation method transmits energy from an electric motor or manually stored operating spring to the operating mechanism to move the main circuit such as a circuit breaker and close the circuit. Therefore, it is common practice to immediately store energy again by starting the electric motor after the discharge operation, and to always store input energy regardless of whether the main circuit such as a circuit breaker is open or closed.

Such an electric spring operating type operating mechanism is disclosed in Japanese Patent Application Laid-Open Nos. 108118-108124 (1982).

FIG. 5 shows a switching mechanism of a motor circuit for storing spring energy in a conventional electric spring-operated circuit breaker.
4A shows a state immediately before the operation spring energy storage is completed, and FIG. 2B shows a state where the operation spring energy storage is completed.

A cam plate 2 is fixed to the main shaft 1 of the mechanism unit, and the cam plate 2 detects the charging and releasing states of an operation spring (not shown). A collar 5 is in contact with the operating plate 4. Switches 6 a s 6 b are disposed below the operating plate 4, and the switches 6 a
By driving the actuator 7 of s6b, the switches 6a and 6b are turned on and off. Further, a display 10 that rotates around a shaft 9 is connected to the collar 5 via a link 8 that is connected with a pin.

Note that the operating plate 4 is rotatably supported by a shaft 11.

When the circuit breaker closes (closes), the mechanism main shaft 1
rotates clockwise, and the cam plate 2 also rotates in the same direction, so the operating plate 4 rotates clockwise about the shaft 11 via the collar 5, and the switches 6a and 6b are turned on. As a result, a motor circuit is formed, an electric motor (not shown) is started, and the operation spring begins to store energy. FIG. 5(a) shows the state just before the operation spring completes the energy storage. When the cam plate 2 further rotates, the state shown in FIG. 5(b) is reached, and the operating plate 4 rotates counterclockwise to switch By turning off 6 a % 6 b, the operation spring is fully charged.

(Problem to be Solved by the Invention) In the switching mechanism of the motor circuit for spring energy storage shown in FIG. The driving part of the actuator tough 6a is driven by the rotation of the cam plate 2.
Since the stroke is in a small range, it is susceptible to mechanical shock.

If the operating plate 4 bounces due to this mechanical impact, chattering is likely to occur in the switch 6b, which may cause a problem of short circuiting the motor circuit. In addition, electromagnetic relays have traditionally been used to operate closing coils and energy storage springs, but the contacts of electromagnetic relays wear out due to the large inrush current of the closing coil and the large starting current of the spring energy storage motor. The state of deterioration is often severe. Furthermore, since the frequency of opening and closing of circuit breakers is generally high, the electromagnetic relay needs to be large and have a sturdy contact structure. For this reason, there are problems in that the high price, large size, and management of maintenance, inspection, etc., become difficult.

Therefore, the present invention can prevent short circuits in the motor circuit due to the occurrence of switch chattering, etc.
The purpose of the present invention is to provide a circuit breaker protection device that is easy to maintain and inspect, has high reliability, is inexpensive, and is compact.

[Structure of the Invention] (Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention stores energy in an operating spring using an electric motor, energizes a closing coil, and closes the circuit through the stored operating spring. A protection device for an electric spring-operated circuit breaker that performs the following: a first switching element connected in series to the closing coil; a second switching element connected in series to the electric motor; a circuit-closing driving circuit that conducts the first switching element for a predetermined period of time in response to a predetermined period of time; and a circuit closing drive circuit that conducts the second switching element after a delay of a predetermined time from the start of release of the operation spring, and the conduction time exceeds a predetermined period of time. 'When an abnormality in the spring energy storage is detected, the second
a spring energy storage drive circuit that turns off the switching element; and a spring energy storage drive circuit that turns off the first switching element in the closing drive circuit during the conduction time of the second switching element by the spring energy storage drive circuit. The gist of the present invention is to include an interlock circuit that forcibly holds the output off, and a failure notification circuit that issues a failure notification when an abnormality in the spring energy storage is detected by the spring energy storage drive circuit.

(Function) The interlock circuit prevents the closing coil from conducting until the operation spring has completed storing energy, thereby preventing a circuit closing operation from being performed in an incomplete spring energy storage state. Further, the spring energy storage drive circuit stores the spring energy of the operation spring after the circuit closing operation is completed. In this way, closing operation or tripping
Since the operation spring starts storing energy after the free operation is completed, a short circuit in the motor circuit due to chattering or the like of the switch in the switching mechanism is prevented. Furthermore, when an abnormality in the spring energy storage of the operating spring is detected, a failure notification circuit issues a failure notification, which facilitates maintenance and inspection work.

(Example) Hereinafter, an example of the present invention will be described based on FIGS. 1 to 4.

In Fig. 1, 12 is a closing contact that closes when it is desired to close the circuit breaker, 13 is a circuit breaker auxiliary contact that closes when the circuit breaker is in an open state, 14 is a closing coil, and 15 is a diode for suppressing surge in the closing coil. The closing coil 14 includes a first field effect transistor (a first switching element for energizing the closing coil).
(hereinafter referred to as FET) are connected in series. 17a is a surge absorption element, 18 is a closing gate circuit as a circuit closing drive circuit of the first FET 16a, and the output g of the closing gate circuit 18 is turned on for a certain period of time after the closing contact 12 is closed; , the first FET 16a is turned on, the closing coil 14 is energized, and the operation spring (not shown) is turned on.
The circuit breaker is closed through the circuit breaker. P-N
is a DC power supply for the operating circuit, and P and -N are DC power supplies for the gate.

FIG. 2 shows each line signal a to g in the closing gate circuit 18.
1 is a timing chart showing operation waveforms of the circuit closing gate circuit 18 when the circuit closing contact 12 is closed in FIG.
This indicates that the signal a immediately becomes the "1" level, and the signal g becomes the "1" level for a certain period of time T1 determined by the circuit constant at the point C in the circuit-closing gate circuit 18.

6a%6b is a switch that closes when the operating spring of the circuit breaker similar to that shown in FIG. 5 is released. Reference numeral 2o denotes a spring energy storage electric motor, and a second FET 16b serving as a second switching element for energization is connected in series to the spring energy storage electric motor 2o. 17b is a surge absorption element. Further, 21 is a braking resistor that is connected in parallel to the spring energy storage electric motor 20 and applies braking to the spring energy storage electric motor 20 when the spring energy storage of the operating spring is completed and the switch 6b is opened. 19 is the second
This is an energy storage gate circuit serving as an energy storage drive circuit that drives the FET 15b. FIG. 3 is a timing chart showing the operating waveforms of each line signal a to g in the energy storage gate circuit 19 during normal operation, and in FIG. 1, the switch 6a.

6b closes, after a delay of a certain time T2 determined by the circuit constant at point h of the spring energy storage gate circuit 19, the second FET 16b for energizing the spring energy storage electric motor 2o is turned on, and the spring energy storage electric motor 2o is turned on. It is designed to drive and store energy in the operating spring.

Point g of closing gate circuit 18 and spring storage gate circuit 1
An interlock diode 22 constituting an interlock circuit is connected between the point b of 9 and the point b of FIG. While the operation spring is storing energy, the signal g of one gate circuit for spring energy storage is "0", and the signal g of the closing gate circuit 18 is "0", which is the same as when the signal is forcibly signaled by the interlock diode 22. Even if the circuit-closing contact 12 closes, the signal g of the circuit-closing gate circuit 18 does not become "1". Therefore, the circuit-closing operation is not performed until the operation spring has completed storing energy. This prevents a circuit closing operation from being performed in an incompletely charged state.

In addition, when the circuit breaker is closed by an opening operation performed during the closing operation when the circuit closing contact 12 is closed, if a time period of T1 or more has elapsed after the circuit closing contact 12 is closed, the first FET 16
Since the circuit breaker a is turned off, the circuit closing operation cannot be performed unless the circuit closing contact 12 is opened once and then closed again, and therefore the pumping operation of the circuit breaker is prevented.

0 In addition, when the circuit breaker is in a closing operation or a trip-free operation, in order to prevent the operation spring from accumulating the spring energy, the start of the spring energy accumulation is delayed by the time T2, so that the switch 6b is automatically activated. Since no physical impact is applied, no chattering or the like occurs, and the second FET 16b is also turned off, preventing a short circuit in the motor circuit.

FIG. 4 is a timing chart showing operation waveforms of signals a to h of each part within the spring energy storage gate circuit 19 during the spring energy storage abnormal operation. In Fig. 1, when a predetermined time period of 13 or more determined by the circuit constant of the 0 point has passed after the switch 6a is closed, the d point becomes the "1" level and the fault alarm circuit is activated as a fault indication of the spring energy storage abnormality. The fault display LED 23 is turned on, and the second FET 16 is turned on.
b is turned off to interrupt the motor circuit and prevent continuous energization. Therefore, the predetermined time period of 13
After the above period of time has elapsed, the second FET 16b is turned off, so that the spring energy storage is in an incomplete energy storage state, and the circuit closing operation in this state is prevented.

[Effects of the Invention] As explained above, according to the present invention, the closing coil is not conductive until the operation spring is fully charged with energy by the in-clock circuit, and the circuit closing operation cannot be executed in the incomplete spring energy storage state. This is prevented, and the spring energy storage drive circuit causes the spring energy storage of the operating spring to occur after the completion of the closing operation. In this way, since the operation spring starts storing energy after the circuit-closing operation or the trip-free operation is completed, it is possible to prevent a short circuit in the motor circuit due to chattering of the switch in the switching mechanism. Furthermore, when an abnormality in the spring energy storage of the operation spring is detected, the failure notification circuit issues a failure notification, which facilitates maintenance and inspection work. Therefore, it is possible to provide a highly reliable, inexpensive and compact circuit breaker protection device since switching elements are used instead of electromagnetic relays to operate the closing coil and motor.

[Brief explanation of drawings]

1 to 4 show an embodiment of the circuit breaker protection device according to the present invention, in which FIG. 1 is a circuit diagram, and FIG. 2 is a timing chart of signals of various parts showing the operation of a closing gate circuit. Fig. 3 is a timing chart of signals of various parts showing the operation of the energy storage gate circuit in normal operation, Fig. 4 is a timing chart of various parts signals showing the operation of the energy storage gate circuit in abnormal spring energy storage operation, and Fig. 5. 1 is a configuration diagram showing a motor circuit switching mechanism in a conventional circuit breaker. 12: Closing contact, 14: Closing coil, 16a:
1st FET (first switching element), 16b = second FET (second switching element), 18: Closing gate circuit (closing drive circuit), 19: Spring energy storage gate circuit (spring storage 20: Spring energy storage electric motor, 22: Interlock diode constituting the interlock circuit, 3 23: Failure display LE0 constituting the failure alarm circuit.

Claims (1)

[Claims] A protective device for an electric spring-operated circuit breaker that stores energy in an operating spring using an electric motor, energizes a closing coil, and closes a circuit via the loaded operating spring, the circuit breaker being connected in series to the closing coil. a first switching element, a second switching element connected in series to the electric motor, a circuit-closing drive circuit that conducts the first switching element for a predetermined period of time in response to a circuit-closing command, and a circuit-closing drive circuit for discharging the operating spring. a spring storage drive circuit that conducts the second switching element after a delay of a certain time from the start of the activation, and turns off the second switching element when a spring storage abnormality is detected in which the conduction time exceeds a predetermined time; , an interlock circuit that forcibly holds off the output for conducting the first switching element in the circuit closing drive circuit during the conduction time of the second switching element by the spring energy storage drive circuit; 1. A protection device for a circuit breaker, comprising: a failure notification circuit that notifies a failure when a spring storage abnormality is detected by a spring storage drive circuit.