JPH04188523A - Dc high-speed vacuum breaker - Google Patents

Abstract

PURPOSE:To enhance the reliability by always monitoring the terminal voltages of a main repulsive capacitor, aux. repulsive capacitor, and high voltage commutation capacitor, which are of importance for maintaining the breaking function. CONSTITUTION:Signal voltages proportioning to the terminal voltages of a main repulsive capacitor 22, aux. repulsive capacitor 23, and high voltage commutation capacitor 24, which are of importance for maintaining the breaking function, are taken out and compared with respective reference values by a comparator of a failure sensor circuit 30 so as to check that charging is made over a specified level. When either value of comparing results is below the specified level, a timer is operated. If the terminal voltage of capacitor is out of level specification even after elapse of a certain period, it is assumed that a failure has occurred in a circuit which is to charge capacitor, and a switching regulator 5 and inverter circuit 6 constituting a charging circuit are stopped. Thereby occurrence of subsidiary troubles is prevented to protect well the apparatus.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a DC high-speed vacuum circuit breaker, and in particular, the main repulsion capacitor and auxiliary repulsion capacitor, which are closely related to the interrupting function, are connected to the state of charge of the high voltage commutation capacitor. This invention relates to a DC high-speed vacuum circuit breaker that constantly monitors and prevents inability to shut off, thereby improving reliability.

[Prior art] A DC high-speed circuit breaker using the conventional pre-charging method was developed in 1986.
As described in Publication No. 3-188843, there is no monitoring circuit for important parts to maintain the shutoff function.
It lacked reliability as a protective device.

[Problems to be Solved by the Invention] Conventional vacuum circuit breakers are not equipped with a monitoring device for important parts for maintaining the circuit breaker function, and lack preparation for the worst case scenario.

The purpose of the present invention is to provide a function to constantly monitor each terminal voltage of the main repulsion capacitor, auxiliary repulsion capacitor, and high-voltage commutation capacitor, which are important for maintaining the cutoff function, in order to compensate for the lack of reliability in the conventional technology described above. The object of the present invention is to provide a DC high-speed vacuum circuit breaker with improved reliability.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a voltage proportional to each terminal voltage of the main repulsion capacitor, the auxiliary repulsion capacitor, and the high voltage commutation capacitor, which play an important role in maintaining the interrupting function. The function of the charging circuit can be monitored and a failure to shut off can be prevented by extracting the signal voltage that has been detected and comparing this voltage with each reference voltage using a comparator and checking that the charging circuit is charged to a specified level or higher. This is how it was done.

[Operation] The terminal voltages of the high-voltage commutation capacitor, the main repulsion capacitor, and the auxiliary repulsion capacitor are each compared with a reference value by a voltage comparator, and when any of the comparison results falls below a specified level, a timer is activated. If the terminal voltage of the capacitor remains below the specified level even after a certain period of time has passed, it is assumed that a failure has occurred in the circuit that charges the capacitor, and the switching regulator and inverter circuit that make up the charging circuit are stopped. It can prevent the next failure and protect the equipment.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 3. As shown in FIG. 1, the DC high-speed vacuum circuit breaker of the present invention has a gate consisting of a logic circuit based on a reset signal R3 and a control signal Z, and an overcurrent detection circuit that compares a signal F proportional to the main circuit current IN with a reference value. A logic circuit 1, a reset coil 2 that closes the main valve 29 according to a reset signal R3, a gate pulse amplifier 3 that generates a gate pulse according to the output of the gate logic circuit 1, and an LED indicating a failure in the charging section.
Display circuit 4 to display, DC input voltage v with large voltage fluctuations
Stabilize 1 to V. an inverter circuit 6 that uses Vo as a power source to drive a transformer 7, a transformer 7 having a low voltage winding and a high voltage winding, and a diode that rectifies the output of the low voltage winding and charges an auxiliary repulsion capacitor 23. 8 and a charging resistor 19, a diode 9 and a charging resistor 20 that charge the main repulsion capacitor 22, resistors 15 to 18 that detect the terminal voltages of the main repulsion capacitor 22 and the auxiliary repulsion capacitor 23, and the main repulsion coil 13 and drive it. the main repulsion thyristor 11, the auxiliary repulsion coil 14 and the auxiliary repulsion thyristor 12 that drives it, the diode 10 and charging resistor 21 that rectify the output of the high-voltage winding and charge the high-voltage commutation capacitor 24, and the high-voltage commutation capacitor 24
A DC voltage transformer 25 checks the terminal voltage of the main circuit current IN, a non-linear resistor 26 suppresses the voltage between electrodes of the main valve 29 when the main circuit current IN is cut off, and outputs a signal F proportional to the main circuit current. It is composed of a DC current transformer 27 that operates when the main circuit current IM is cut off, an auxiliary valve 28 that forms a discharge circuit for the high-voltage commutating capacitor 24, a main valve 29 that energizes and cuts off the main circuit current I4, and a failure detection circuit 30. has been done. Next, as shown in FIG. 2, the failure detection circuit 30 compares the output of the DC voltage transformer 25 with the reference voltage V and
A comparator 3I that outputs V D 1 , a comparator 32 that compares the voltage A proportional to the terminal voltage of the main repulsive capacitor 22 with a reference voltage v 2 and outputs L V D x, proportional to the terminal voltage of the auxiliary repulsive capacitor 23 a comparator 33 that compares the voltage B and the reference voltage v3 and outputs L V D 3;
The OR circuit 34 outputs the OR conditions of L V D 1 to L V D a, and the time period triggered by the rising edge is T.
2 timer 35, a D-T flip-flop 36 that determines failure of the charging section at the rising edge of the output T+H of the timer 35, and a memory circuit 37 that latches this output.
It is made up of.

The operation of the DC high-speed vacuum circuit breaker of the present invention will be explained with reference to the timing chart of FIG.

At UO in Fig. 3, when the reset signal R3 changes from the ``H'' level to the If LI+ level, the stop signal SP becomes the ILHIt level, and when the conditions for activation by the control signal Z are met, the current cutoff command K is issued. When the level becomes ``L'', the switching regulator 5 and the inverter circuit 6 are started, and the output V of the switching regulator 5 becomes low. rises to a specified voltage, and the operation of the inverter circuit 6 causes the transformer 7 to generate a rectangular wave AC voltage in the low voltage winding and the high voltage winding. This rectangular wave alternating current voltage is half-wave rectified by diodes 8 to 10, charges the main repulsion capacitor 22, the auxiliary repulsion capacitor 23, and the high voltage commutating capacitor 24 through the charging resistors 19 to 21, From t1 to t2, the terminal voltage of each capacitor is at a specified level Vl.

Reach v2 and v3. At this startup, the timer 35 of the failure detection circuit 30 counts time from to, and the time limit T2
It is monitored that the terminal voltages of the aforementioned capacitors reach the specified levels VL, V2, and v3 within a certain period of time. At 1.3, the main circuit current Is begins to flow. , an abnormal phenomenon occurs in the main circuit load, and the main circuit current I
s is the overcurrent detection level ■. Since the main circuit current exceeded cR, the main circuit current 1. The output signal F of the DC current transformer 27 proportional to s causes the gate logic circuit 1 to detect an overcurrent and output a current cutoff command K. When the current cutoff command K changes from the ``L'' level to the ``H°'' level, the gate pulse amplifier 3 is tripped to generate the gate pulse Gi and turn on the main repulsion thyristor 11. On the other hand, the current cutoff command K , switching regulator 5 and inverter circuit 6
stops. When the main repulsion thyristor 11 is turned on, the discharge current of the main repulsion capacitor 22 excites the main repulsion coil 13 and separates the contact of the main valve 29. Next, in order to turn on the auxiliary repulsion thyristor 12 by generating the gate signal G2, the gate pulse amplifier 14 excites the auxiliary repulsion coil 14 by the discharge current of the auxiliary repulsion capacitor 23, and turns on the contact of the auxiliary valve 28. let When the contact of the auxiliary valve 28 is turned on, the high-voltage commutating capacitor 24 causes a discharge current to flow in the opposite direction to the main circuit current Is through the arc discharge between the poles of the main valve 29, and at 6°, the main circuit current Is flows. The current in the valve 29 becomes zero, and the main circuit current IN is cut off. After the main circuit current ■- is cut off, the high voltage commutating capacitor 24 connects the auxiliary valve 2
While the inductance of the main circuit load absorbs the generated surge voltage through the contacts No. 8, the voltage between its terminals increases rapidly. When this inter-terminal voltage reaches the operating level of the non-linear resistor 26, the inter-electrode voltage of the opened main valve 29 is suppressed. After that, at L7, the gate signal G2
When the auxiliary repulsion capacitor 23 is depleted, the excitation ability of the auxiliary repulsion coil 14 disappears, so the auxiliary valve 28 is opened and the high voltage commutation capacitor 24 is connected to the high voltage winding of the transformer 7. →Discharge through the diode 10-charging resistor 21 path. After a certain period of time T1 has elapsed since the current cutoff command K was output, the switching regulator 5 and the inverter circuit 6 are automatically restarted to charge each capacitor. During this series of current interruption operations, the timer 35 of the failure detection circuit is counting time, and the interruption is completed within a certain time Tz after the inverter circuit 6 is stopped by the current interruption command K, and each capacitor is Since recharging is completed, failure detection is not performed. In addition, when the device of the present invention detects an overcurrent and cuts off the current, it is treated as a reset so that the main valve remains open and does not return unless the reset coil is pressurized. It has become. In step 1, when a reset signal R3 treated as a reset is input, the gate logic circuit 1 is reset, the current cutoff command is canceled, and the reset coil is energized to close the main valve. In NXO, the high voltage commutating capacitor 2 is damaged due to a failure in the charging circuit, such as a rare show in the high voltage winding of the transformer 7, or a break in the diode 10 or the charging resistor 21.
The terminal voltage of 4! drops, and the output signal D-E of the DC voltage transformer 25 detecting this decreases. When the li voltage drops below V1, the output L of the comparator 31 of the failure detection circuit 30
V D 1 changes from the "L" level to the II HI+ level, triggering the timer 35. Even at time t after the time limit T2 of the timer 35 has elapsed, the signal DE remains below the reference voltage V1, so the output of the OR circuit 34 is "
The rising edge of the output TIM of the timer 35 triggers the DT flip-flop 36, so its output Y changes from II) (I+ level to "L").
level, triggers the memory circuit 37, changes its output, that is, the stop signal SP, from the H' level to the "L" level, and latches the failure occurrence information.The latched stop signal SP is transferred to the switching regulator. 5 and the inverter circuit 6 are stopped, and the fault display circuit 4 is operated, and the output FD lights up the LED 38 to display the fault condition. - Once the fault occurrence is memorized, the fault display circuit 4 is activated until the reset signal is input. , this state remains maintained.

According to this embodiment, the circuit system is used to charge the main repulsion capacitor and the auxiliary repulsion capacitor through half-wave rectification using a common midpoint from the secondary winding of the isolation transformer 7, so that the terminal voltage of both capacitors is detected. In this case, it can be easily used as a signal source for a low voltage circuit by simply dividing the voltage using resistors. In addition, the terminal voltage of the high-voltage commutating capacitor is isolated from the high-voltage circuit by a DC voltage transformer, and a signal voltage proportional to the terminal voltage of the capacitor is extracted, so the failure detection circuit is configured with a 1C comparator and a TTLic. , miniaturization can be achieved.

[Effects of the Invention] In the system of the present invention, when interrupting the main circuit current, which is an important function as a protection device, all the energy for interrupting the interrupt is supplied by a large capacitor. It is necessary that the main repulsion capacitor, auxiliary repulsion capacitor, and high voltage commutating capacitor be kept sufficiently charged at all times. Therefore, by constantly monitoring the state of charge of each of the capacitors described above, there is an effect of increasing reliability as a protection device.

[Brief explanation of drawings]

FIG. 1 is a system diagram of an embodiment of the present invention, FIG. 2 is a block diagram of a failure detection circuit of the present invention, and FIG. 3 is a timing chart showing the operating state of the embodiment of the present invention. 1... Gate logic circuit, 2... Reset coil, 3
...Gate pulse amplifier, 4...Fault indication circuit, 5
...Switching regulator, 6...Inverter circuit, 7...Transformer, 8-10...Diode,
11... Main repulsion thyristor, 12... Auxiliary repulsion thyristor, 13... Main repulsion coil, 14... Auxiliary repulsion coil, 15-18... Resistor, 19-21... Charging resistor , 22... Main repulsion capacitor, 23... Auxiliary repulsion capacitor, 24... High voltage commutation capacitor, 2
5... DC voltage transformer, 26... Nonlinear resistor, 2
7... DC current transformer, 28... Auxiliary valve, 29...
・Main valve, 3o...Failure detection circuit, 31-33...
・Comparator, 34...OR circuit, 35...Timer, 3
6...I)-T...Flip flow LLJ
cco Yamada Figure 3

Claims (1)

[Claims] 1. A switching regulator that stabilizes the voltage of a DC power supply that fluctuates; a transformer that uses the output of the switching regulator as a power source; an inverter circuit that uses the output as a power source; a transformer that has high-voltage and low-voltage output windings; and a diode that rectifies the output voltage of the transformer. and charging resistor, main repulsion capacitor, auxiliary repulsion capacitor, main repulsion coil and main repulsion thyristor, auxiliary repulsion coil and auxiliary repulsion thyristor, high voltage commutation capacitor, non-linear resistor, auxiliary valve and main valve, detecting the main circuit current In a DC high-speed vacuum circuit breaker composed of a DC current transformer, a gate logic circuit, and a gate pulse amplifier, a failure detection circuit constantly monitors each terminal voltage of the main repulsion capacitor, the auxiliary repulsion capacitor, and the high voltage commutation capacitor. If the terminal voltage of each capacitor continues to be out of the specified range for a certain period of time, it is assumed that a failure has occurred and the operation of the switching regulator and inverter circuit is stopped to protect the normal parts. A DC high-speed vacuum circuit breaker characterized by: