JPS62110213A - Dc circuit breaker circuit - 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 [Industrial Application Field] The present invention relates to a DC breaker circuit, and particularly to an Arcane-type DC breaker circuit used for nuclear fusion power sources and DC power transmission.

[Conventional technology]

FIG. 2 shows, for example, the Japanese Patent Publication No. 9/-/2T, 3 according to the present application.
．． In Figure 2, which is a schematic configuration diagram of a conventional DC breaker circuit shown in Publication No. 3, (1) shows a load (2) and a breaker (1) between both ends of the DC power supply (1). A series circuit including a switch, an inductor, and a capacitor power source (6) is connected in parallel with the circuit breaker (, 7).

Further, FIG. 3 illustrates a waveform diagram of a current flowing through the circuit breaker (3) when a circuit breaker operation is performed in the conventional DC breaker circuit array shown in FIG.

The operation of the conventional example will be described below with reference to FIGS. 1 and 3. Now, at time (t), breaker (3) is opened, and at the same time (breaker (3)
The switch ('
4) shall be closed. At this time, depending on the polarity of the pre-charged capacitor power supply (6), if the polarity is (→, the waveform is ↓(→) at the time (t,), and if the polarity is (-1-1), the waveform is As shown by L(+), at time (t,'), the '1 flow (I) flowing through the breaker (,?) becomes zero, and accordingly, the intended breaker operation is performed. If the breaker at this point (t,) or (t,') fails, the intended breaker will fail υ when the current flowing through the breaker (3) becomes zero in the next cycle. The inductor (RI) is connected to the circuit breaker (
3) is used to adjust the time constant that defines the time from opening until the current flowing through it becomes zero.

Since the conventional, well-known DC breaker circuit is configured as described above, arc plasma is generated between the electrodes of the breaker between the time the breaker opens and the time when the current flowing through the breaker becomes zero. There is. Then, the electrodes of the breaker are damaged by the arc plasma, resulting in a shortened lifespan.

Furthermore, due to the presence of the arc plasma, even if the current flowing through the breaker becomes zero, at the next moment the current tends to flow in the opposite direction, causing the breaker to fail. There were problems such as the possibility of storage.

In view of the shortcomings of the known DC breaker circuits, the present applicant has proposed an improved DC breaker circuit as shown in Fig. proposed a device circuit.

In Figure D, (7) is a variable voltage DC power supply.
This connects the load coil (/3
)It is connected to the. In addition, a series circuit consisting of a capacitor power supply (q) and a switch (10) and a breaker resistor (/2) for absorbing energy are connected in parallel to the series circuit of the breaker (g) and the diode (//). It is connected to the. And the crowbar switch (/I
I) is connected in parallel with the DC power supply (7), and a current sensor (f) is provided to detect the current of the circuit breaker (f). Note that an inductor (/A) is inserted in the series circuit consisting of the capacitor power supply (9) and the switch (10) as necessary. The command circuit (/7) is connected to the current sensor (/7).
) The circuit breaker (r) is opened and closed by the output signal of the circuit breaker (r).

Next, the operation of the circuit shown in Fig. 9 will be explained with reference to Fig. 2 which shows the operating waveforms of the DC breaker circuit shown in Fig. 9. First, the DC power supply (7) is energized, and the current flowing through the load coil (/3) is raised to a constant value (■,). At this time, the current flowing through the load coil (/3) and the breaker (
The currents flowing through the two are approximately equal to each other. After a predetermined amount of energy is stored in this energized load coil (/3), the crowbar switch (/lI) is closed, and the current flowing through the load coil (/J) is crowbared by the crowbar switch (c0). , the DC power supply (7) is disconnected from the circuit.

Then, at time (t,) with the occurrence of a failure,
The switch (10) is closed and the capacitor power supply (9)
A more transient current (k, ) begins to flow through the breaker (r) in the opposite direction to the current (k, ) and decreases over time. Therefore, at time (t,), both currents (k, ) and (
The difference between the current and Generally, the time difference between time points (t,) and time points (t,) is extremely short.

Then, at time (t), the current sensor (tr) senses that the current flowing through the breaker (g) has become zero, and an opening command signal is sent to the breaker (g) by the command circuit (
/7), and the circuit breaker Cl) is opened at a time (t, ) after these fixed delay times. At this time, since no current is flowing through the breaker (r), no arc plasma is generated between the electrodes of the breaker (r).

[Problem that the invention seeks to solve]

The conventional DC breaker circuit of the applicant mentioned above has various advantages, but after successfully breaker, the capacitor power supply (9)
There was a problem in that the capacitor power supply (9) was overcharged in the reverse direction due to the ITT flow from the inductor (13).

This invention was made in order to solve the above-mentioned problems, and provides a DC breaker circuit that does not damage the breaker electrode, can cut off the circuit reliably in a short time, and can deeply protect the capacitor power supply. The purpose is to obtain.

[Means for solving problems]

The DC breaker circuit according to the present invention includes a series circuit of a breaker and a rectifier between a DC power source and a load, a series circuit of a capacitor power source and a switch in parallel with this series circuit, and further includes: This system detects an excessively high backlight voltage of a capacitor power supply that exceeds a predetermined value and provides a discharge path to the capacitor power supply.

[Effect]

According to this invention, by closing the switch connected in series with the capacitor power supply, the current flowing from the capacitor power supply reduces the direct current flowing to the breaker to zero, and this zero current is detected to open the breaker and perform the breaker operation. Performed without arcing.

When the capacitor power supply is cut off, when the capacitor power supply is charged to an excessive reverse voltage, this is detected and the capacitor power supply is discharged.

〔Example〕

Hereinafter, one embodiment of the DC breaker circuit according to the present invention will be described with reference to the drawings.

Figure 1 is a configuration diagram of the above embodiment.The difference from Figure 7 is that the reverse voltage detection circuit (W) is connected in parallel to the capacitor power supply (W).
7g) is connected, and a series circuit of a discharge start switch (/9) and a discharge resistor (2o) is also connected. The reverse voltage detection circuit (/j) is connected to the capacitor power supply (
9) is charged with an excessive reverse voltage, this is detected and a discharge command signal is given to the switch (/?).
) can be controlled to open and close. The other parts or elements are the same as those in Fig. 1, so their explanation will be omitted.

Next, the operation of the above embodiment will be explained. Incidentally, since the waveform diagram in the configuration of FIG. 1 is basically the same as that in FIG. 1, the explanation will be made with reference to FIG.

First, one DC source (A) is connected to the load coil (/3) and energized to excite it. After the current flowing through this load coil (/3) reaches a certain value (r,)i,
When the voltage of the DC power supply (7) is lowered, a circuit consisting of a diode (//), a breaker (ZA), a load (/J), and a switch (/Q) is activated by the action of the crowbar diode or switch (/L). A constant current flows within the time constant range set for the DC power source (7), and the DC power source (7) is disconnected from the load coil (/3). At this time, the current flowing through the load coil (/3) is equal to the current (1,) flowing through the breaker (ZA), and thereby energy is stored in the load fill (tJ).

Next, at time (t,) due to the occurrence of a failure, the second switch (10) is closed by an external command, and current (t,
) flows into the breaker (r), and the direction of this - current (Eyu) is opposite to the current (Sh) that previously flowed through the breaker (r). As a result, the total breaker current (1 , -T,) starts to decrease at time (t,) and reaches zero at time (t,). In the diagram, the dashed line is the breaker (g)
Do not insert a diode (/l) in series with the breaker (
This is the 1st current waveform when r) remains in the closed state, and it takes a negative value from time (t,) to (t,) and takes a negative value at time (t,).
The re-it current becomes zero in the diode (//)
When the capacitor power supply (9) is inserted, the cutoff current does not reverse as shown by the dotted line, and the zero current value is maintained for a period (T) determined by the charging/discharging circuit constant of the capacitor power supply (9).

The current sensor (/7) detects this zero current value and instructs the command circuit (/7) to open the breaker (r).

Therefore, since no current flows through the breaker (g) during this period (T), no arc plasma is generated between the breaker electrodes even if the breaker (g) is opened. When a voltage is generated between the electrodes of the breaker (g) due to the complete shutoff operation, the gap between the electrodes has widened, so there is no arc plasma, and the breaker (r) ) can have high dielectric strength. The operation up to this point is the same as in the case of FIG.

On the other hand, the capacitor power supply (q) is connected to the resistor (/2), the load (/,,?), the switch (C0, the λth switch (10) and the inductor (13), but when the reverse voltage of the capacitor power supply (9) exceeds a predetermined value, the reverse voltage detection circuit (7g) detects this. Detects the voltage and sends a discharge command signal to the discharge switch (/9) to close it before an excessive reverse voltage occurs. Connect the discharge resistor (10> in parallel to the capacitor power supply (9) and turn the capacitor power supply (9) on. A discharge path is formed to prevent excessive reverse charging, and the current can be attenuated together with the cutoff resistor (/) to completely cut off the current.

In the above embodiments, the case where a coil is used as the load has been described, but the present invention is not limited to this, and the same effect can be achieved even when a load resistor is used.

However, in this case, the cutoff resistance (1) is no longer necessary. Furthermore, since stray inductance is usually included, the inductor (/3) may be removed by adjusting the time constant.

Furthermore, since the breaker (r) generally moves the electrode mechanically, if it takes a certain amount of time to open the circuit breaker after receiving the open signal, the circuit breaker (r) may be operated separately from current detection. Alternatively, an open signal may be input. That is, in response to the occurrence of a failure, first an open signal is given to the breaker (r), and the switch (10) is turned on earlier by the time corresponding to the time from the above-mentioned predetermined time (t,) to (t). It may be opened.

In this case, the current sensor (/j) is not required. Further, if the switch (/θ) also requires a predetermined delay operation time, the switch (10) may also be instructed to operate early.

〔Effect of the invention〕

As explained above, in the DC breaker circuit according to the present invention, when the switch is closed, the current flowing through the breaker is reduced to zero by the current flowing from the capacitor power supply, and the current zero is detected to perform the breaker operation. However, when the capacitor power supply is excessively reverse charged during cut-off operation, we created a discharge path in parallel to the capacitor power supply, so
This prevents the capacitor power supply from being charged to an excessive reverse voltage, thereby preventing damage to the capacitor power supply, and has the effect of assisting the cutoff operation.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a DC breaker circuit according to an embodiment of the present invention, FIG. 1 is a schematic diagram of a conventional, well-known DC breaker circuit, and FIG. Figure 1 is a schematic diagram of the conventional DC breaker circuit according to the applicant's previous application, and Figure 3 is the breaker of the DC breaker circuit of Figures 1 and 9. This is a waveform diagram of current. (7)φ・DC power supply, (r)・・breaker, (9)・−
Capacitor power supply, (lO) pot-switch% (//)・
- Rectifying element, (/3)...Load, (/Even)...Current sensor, (/A)...Inductor, (/7)φe command circuit,
(7g) - Reverse voltage detection circuit, (/?) - Discharge start switch, (,20) - Discharge resistor. In each figure, the same reference numerals indicate the same or corresponding parts. Agent: Teru Zeng. Selling figure 1

Claims (3)

[Claims] (1) In a DC or disconnection circuit in which direct current or disconnection is performed by a disconnector installed between a DC power source and a load, a rectifying element connected in series with the disconnector or disconnector, A series circuit of at least a capacitor power supply and a switch connected in parallel to a series circuit of a switch and a rectifier, detects when the current flowing through the switch becomes zero and disconnects the switch. 1. A direct current or decisive circuit, comprising means for commanding the capacitor power supply to open, and means for detecting an excessive reverse charge voltage of a predetermined value or higher in the capacitor power supply and providing a discharge path to the capacitor power supply. (2) The means for issuing an open command includes a current sensor that detects the shingle breaker current, and a command circuit that outputs an open command signal to the shingle breaker when the sensor detects zero shingle breaker current. A direct current or disconnection circuit according to claim 1, comprising: (3) The means for providing the discharge path is connected to both ends of the capacitor power supply, and includes a reverse voltage detection circuit that generates a discharge command signal for the capacitor power supply when the excessive reverse voltage is detected; A direct current or disconnection circuit according to claim 1 or 2, comprising a series body of a discharge resistor and a discharge start switch that is connected and closed by the discharge command signal.