JPH06168643A - Circuit breaker operating device - Google Patents

Abstract

PURPOSE:To prevent malfunction by arranging a circuit to give a detecting signal when an operation coil current is not more than an operating current, turning on A in always-off and always-on opening and closing elements A and B connected in series to each other by an operation signal, and turning off B by the detecting signal when the operation signal is not given. CONSTITUTION:Always-off and always-on opening and closing elements 3 and 4 and an operation coil 2 are connected in series to each other, and are connected to operating electric power supply 1, and a drive circuit 5 turns on the element 3 by an operation command signal (a) from a signal terminal 6, and flows an electric current to the coil 2. A current supply detecting circuit 7 composed of a DC current transforming passage 8 and a DC amplifying circuit 9 outputs a signal (b) by detecting an operating current of the coil 2 before it reaches the minimum operating current. When the signal (b) is given when the signal (a) is not given, an OR circuit 10 composed of inverters 11 and 14, an AND circuit 12 and a latch circuit 13 latches the signal, and turns off the element 4. Thereby, malfunction of the opening and closing elements cased by a surge or the like can be avoided, so that malfunction of a circuit breaker can be prevented beforehand.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit breaker operating device.

[0002]

2. Description of the Related Art In a circuit breaker, for example, a power circuit breaker, a closing coil or a trip coil (hereinafter simply referred to as an operating coil) is used for starting or closing the circuit breaker. In general, the operation coil is energized and excited based on the operation command signal, and the electromagnetic force generated thereby urges the plunger to activate the operation mechanism.

Conventionally, when an operation command signal is given,
The mechanical relay contact was turned on, which energized the operating coil. However, such mechanical relay contacts are slow to turn on and off and cannot respond to abrupt changes, and may malfunction due to vibration, or malfunction due to contact oxidation or contamination. is there.

In order to solve these problems, it is conceivable to use a switching element made of a semiconductor element such as a transistor, instead of a mechanical relay contact. However, since the operating coil is an inductive load with large inductance, surge voltage is likely to occur when the switching element is turned off,
Also, in substations where circuit breakers are frequently used, switching surges from other equipment frequently occur, so if switching elements consisting of semiconductor elements that are weak against surges are used easily, malfunctions will occur, and therefore general electrical equipment It was not easy to use for a circuit breaker that requires much higher reliability than the above.

[0005]

SUMMARY OF THE INVENTION According to the present invention, even when a switching element made of a semiconductor element is used as a switching element for controlling the energization of an operating coil of a circuit breaker, a malfunction due to a surge or the like is prevented. With the goal.

[0006]

SUMMARY OF THE INVENTION The present invention is a power supply for operation,
An operation coil of a circuit breaker, a semiconductor element, and a first opening / closing element that is turned on based on an operation command signal and a second opening / closing element that is a semiconductor element are connected in series, and the operation power source performs the operation. An energization detection circuit that detects energization to the operation coil and outputs an output signal before the operation current flowing through the coil reaches the minimum operation current of the operation coil; and an output from the operation command signal and the energization detection circuit. The signal is used as a logic input, and when the both logic inputs are both input and when both are not input, the second
And a logic circuit that outputs a logical output that turns on the second opening / closing element when at least one of the two logic inputs is not input.

[0007]

When the operation command signal is not given and the energization detection circuit does not output, and when the operation command signal is given and the energization detection circuit outputs,
All the second opening / closing elements are in the ON state.

However, since the operation command signal is not given,
When the output of the energization detection circuit is present, the second switching element is turned off by the time the current flowing through the operating coil reaches its minimum operating current. In this case, since it is considered that the first opening / closing element is malfunctioning, malfunctioning due to the operation coil is avoided.

Further, even when the operation command signal is given and there is no output of the energization detection circuit, the second opening / closing element is turned off. In this case, it is considered that the first switching element has a failure. As described above, the malfunction of the circuit breaker due to the malfunction of the first switching element can be prevented in advance, and the failure of the first switching element can be known if necessary.

[0010]

EXAMPLE An example of the present invention will be described with reference to FIG. 1
Is a power supply for operation, 2 is an operation coil of a circuit breaker, 3 is a first switching element, and 4 is a second switching element. Both opening and closing elements 3, 4
Is composed of a semiconductor element such as a transistor. Reference numeral 5 denotes a drive circuit for the switching element 3, which outputs a signal from a signal terminal 6 to which an operation command signal is applied. The opening / closing element 3 is turned on by this output.

Reference numeral 7 is an energization detecting circuit for detecting the flow of an operating current flowing through the operating coil 2. The example in the figure shows the operation coil 2
The DC current transformer 8 is composed of a Hall element or the like inserted in the circuit in which the operating current flows, and the DC amplifier 9 whose output is the target.

When current starts to flow from the operating power supply 1,
Due to a transient phenomenon caused by the inductance of the operating coil 2, it usually takes several milliseconds or longer for the current to reach the minimum operating current of the operating coil. The energization detection circuit 7 detects an operating current before reaching the minimum operating current and outputs an output.

A logic circuit 10 includes an inverter 11 to which an operation command signal is input, an AND circuit 12 to which the output of the energization detection circuit 7 and the output of the inverter 11 are input, and a latch to which the output of the AND circuit 12 is input. It is composed of a circuit 13 and an inverter 14 to which the output of the latch circuit 13 is input. When the inverter 14 outputs a logical output, the switching element 4 is turned on.

When no operation command signal is given and no current is flowing through the operation coil 2, the switching element 3 is in the off state, and the logic circuit 10 is in the state latched by the latch circuit 13. Then, since the output is output from the inverter 14, the switching element 4 is in the ON state.

When an operation command signal is given to the signal terminal 6, the switching element 3 is turned on, and a current starts to flow from the operation power supply 1 to the operation coil 2. Initially, the current is equal to or lower than the minimum operating current of the operating coil 2, but when the current gradually increases and reaches the minimum operating current, the operating coil 2 operates and the closing operation of the circuit breaker is started.

If the switching element 3 is turned on even though the operation command signal is not given under the influence of a surge or the like, a current starts to flow in the operation coil 2 by this, but this is the minimum operation. Before reaching the current, the energization detection circuit 7 detects the current and outputs an output.

In the logic circuit 10, since the output is given from the energization detection circuit 7 even though the operation command signal is not given, the logic output from now is lost and the switching element 3 is turned off. The state where the logical output is lost is latched by the latch circuit 13. As a result, even if the switching element 3 malfunctions, malfunction of the circuit breaker due to the operation coil 2 is avoided.

As can be seen from the above description, the switching element 4 is always on and in a low impedance state. Therefore, even if a surge occurs, the surge passes through the switching element 4 without any damage, so that the risk of destruction by the surge is extremely small.

If no current flows through the operation coil 2 despite the operation command signal being given, no logic output is output to the logic circuit 10. In this case, it is considered that the switching element 3 or 4 has a failure. Therefore, if an alarm or display operation is performed by the operation command signal and the logic output of the logic circuit 10, these failures are notified. be able to.

The energization detection circuit 7 in the illustrated configuration is
The energization to the operation coil 2 is detected by detecting the current flowing through the operation coil 2. However, instead of this, the energization to the operation coil 2 is detected from the voltage across the operation coil 2. May be.

[0021]

As described above, according to the present invention, even when the switching element made of a semiconductor element is used to control the energization of the operating coil of the circuit breaker, malfunction of the switching element due to surge or the like can be avoided, This has the effect of preventing malfunction of the circuit breaker.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention.

[Explanation of symbols]

 1 Operation Power Supply 2 Operation Coil 3 First Opening / Closing Element 4 Second Opening / Closing Element 6 Signal Terminal to Which Operation Command Signal is Applied 7 Energization Detection Circuit 10 Logic Circuit

Claims (1)

[Claims] 1. A first switching element, which comprises an operating power supply, an operating coil of a circuit breaker, and a semiconductor element, and is turned on based on an operation command signal, and a second switching element including a semiconductor element, which are connected in series. A series circuit, and an operation current flowing from the operation power supply to the operation coil before reaching the minimum operation current of the operation coil, and an energization detection circuit that detects energization to the operation coil and outputs an output signal, The operation command signal and the output signal from the energization detection circuit are used as logic inputs, and the second switching element is turned on when both logic inputs are being input and when not being input at the same time. A circuit breaker operating device comprising: a logic circuit that outputs a logic output that turns off the second switching element when at least one of the logic inputs is not input.