JPS62110215A - 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 [Field of Industrial Application] The present invention relates to a DC breaker circuit, and particularly to a DC breaker circuit used in nuclear fusion power sources and DC power transmission.

[Conventional technology]

Figure 1 shows, for example, the Japanese Patent Publication Show Q/-/Kota 3 related to the present applicant.
FIG. 3 is a schematic configuration diagram of a conventional DC breaker circuit shown in Publication No. 3. In this figure, (1) is a series circuit with a load (k) and a breaker (,7) connected between both ends of the DC power supply (1), and a switch ('I).
, an inductor D) and a capacitor power supply (6) are connected in parallel with the circuit breaker (3).

Further, FIG. 1 illustrates a waveform diagram of a current flowing through the breaker (3) when a disconnection operation is performed in the conventional DC breaker circuit example of FIG. 4.

The operation of the conventional example will be described below with reference to FIG. 4 and FIG. Now, at time (t7), the breaker (,?) is opened, and at the same time (breaker (3)
At this time, depending on the polarity of the pre-charged capacitor power supply (B), the waveform ↓ (→ As shown, at time (t),
In addition, when the polarity is (-1-), the current (r) flowing through the breaker (3) becomes zero at the time (tyu') as shown in the waveform Q (+), and accordingly, the intended breaker will be held.

And at this point (t, )'! Take (1,, / )
If the breaker fails, the intended breaker is repeated in the next cycle when the current flowing through the breaker (3) becomes zero. Note that the inductor 0) is used to adjust the time constant that defines the time from when the breaker (3) opens until the current flowing through it becomes zero.

Since the conventional well-known DC breaker circuit is configured as described above, arc plasma exists for a long time, so
Even if the current flowing through the breaker becomes zero, at the next instant, the current tends to flow in the opposite direction, causing problems such as failure to shut off.

In view of these shortcomings of known DC breaker circuits, the present applicant proposed an improved DC breaker circuit as shown in FIG. Ta.

In Fig. 6, (7) is a variable voltage DC power supply,
This is connected to the load coil (
/ evening). In addition, a capacitor power supply (/
A power source different from the DC power source (7) such as the Each is connected in parallel. A crowbar diode (/6) is connected between the connection point of the switch (1) and the breaker (q) and one end of the DC power supply (7), and is further connected in parallel with the breaker (9). A voltage detection circuit (/7) is provided. Note that the switch (/hiro) is controlled to open and close by the output of this voltage detection circuit (17).

Next, the operation of the conventional example shown in FIG. 6 will be described with reference to the waveform of the breaker current shown in FIG. First, the first switch (g) is closed, and the DC power source (7) is connected to the load coil (coil) to energize and excite it. The current flowing through this load coil (l4) is
If the voltage of the DC power supply (7) is lowered after reaching a certain value (I/), the effect of the crowbar diode (/6) will be constant within the time constant set for the energized circuit. As the current flows, the DC power source (7) is disconnected from the load coil (/i).

Next, when a failure occurs, the breaker (wa) is opened at time (t,), and at the same time, the breaker (wa) is closed. Jitter often occurs when circuit breaker (D) opens, and in actual operation, the voltage detection circuit (/7) detects the voltage rise across both ends of circuit breaker (9) when it opens. ,
The output of this is configured to close the third coswitch (C0).

By closing the second co-switch (/II) in this way, a current flows in the opposite direction (
) flows transiently, and due to this, the current flowing through the breaker (q) decays rapidly and becomes zero at time (t, ). In the time period from this time point (t,') to the time point (t,), arc plasma is generated between the electrodes of the breaker (V). After time (t,).

Until a predetermined time (t,), the current flowing through the breaker (9) is brought to zero by the action of the diode (10).

Then, in the time period from this time point (t,) to the time point (tyo), the arc plasma generated between the electrodes of the breaker (V) is sufficiently attenuated and finally disappears. After time (t,), the current from the capacitor power supply (l) tries to flow to the breaker (9), but at this time, the current cannot flow because the breaker (?) is already completely open. When the intended cutoff operation is completed, the current flowing through the load coil (/l) flows through the cutoff resistance (//) and is attenuated. In the above, when the diode (/) is removed and the cutoff fails, a current as shown by the dotted line in FIG. 1 will flow.

[Problem that the invention seeks to solve]

The above conventional DC breaker circuit of the present applicant has various advantages, but the first problem is that the period (t, -1,) until the breaker current becomes zero is short;
There was a possibility that the shear arc plasma would not completely disappear and therefore a failure would occur.

Furthermore, as the problem of No. 3, after the shutdown is successful, the late Km is connected from the capacitor power supply (12) through the inductor (/J).
There was a problem in that the capacitor power supply (/J) was reversely charged by the current.

The present invention has been made to solve the above-mentioned problems, and provides a DC breaker circuit that can reduce damage to the breaker electrode, can perform the breaker operation reliably in a short time, and can protect the capacitor power supply. The purpose is to obtain.

[Means for solving problems]

A DC breaker circuit according to a first invention for solving the first problem described above includes a series circuit of a breaker, a rectifying element, and a saturable reactor provided between a DC power source and a load,
In parallel with this series circuit, a series circuit is provided that includes at least a capacitor power supply and a switch that closes in response to a command to open the circuit breaker, and the switch is closed based on the command to open the circuit breaker. .

Furthermore, a DC breaker circuit according to a second invention which solves the above-mentioned problem No. It is designed to detect this and provide a discharge path to the capacitor power supply.

[Function] According to the first invention, when the switch is closed in response to an opening command to the breaker, the current flowing through the breaker is made zero by the current flowing from a different capacitor power source, and Due to the saturable reactor, the current change rate is small near zero I current, extending the period in which the current can be considered to be substantially zero, and these periods in which the current is substantially zero, which can be considered to be zero DC or almost zero, are predetermined. Connected for a period of time.

According to the invention No. 1, after the capacitor power supply starts charging in the reverse direction after operation, the excessive optical direct voltage is detected, the discharge start switch is closed, and the discharge resistor is connected in parallel to the capacitor power supply to discharge the capacitor. This prevents the capacitor power supply from being overcharged in the opposite direction.

〔Example〕

Hereinafter, embodiments of the DC breaker circuit according to the first and first aspects of the present invention will be described with reference to the drawings.

FIG. 1 is a configuration diagram showing an embodiment of the first invention, and FIG. 2 shows a waveform diagram of the breaker current in the above embodiment.

First, FIG. 1 differs from FIG. 6 in that a saturable reactor (/l) is newly inserted in series with the series circuit of a breaker (wa) and a diode (lθ). The other parts or elements are the same as those shown in FIG. 6, so their explanation will be omitted.

Next, the operation of the embodiment shown in FIG. 1 will be explained with reference to FIG.

First, close the first switch, connect the DC power supply (A) to the load coil (Y), and energize it to excite it. When the voltage of the DC power supply (7) is lowered after the current flowing through the load coil (11) reaches a certain value, the closing action of the crowbar diode (16) causes the diode (10 ), breaker (9), saturable reactor (15), load (/4), and diode (/
A constant current flows within the time constant range set for the circuit consisting of 6), and the DC power supply (7) is disconnected from the load coil (/4). At this time, the current flowing through the load coil C7t) is equal to the current flowing through the breaker (9), and thereby energy is stored in the load coil C7t.

Next, at the time point (1,,) due to the occurrence of a failure,
An external command is given to open the circuit breaker (9). The voltage detection circuit (/7) closes the second switch (C0) in accordance with the voltage across the breaker (W) as in the case of FIG.

As a result, the current flowing from the capacitor power supply (/2) (
), the total breaker current (I, -1,) is the second
As shown in the figure, it begins to decrease rapidly.

However, the point at which the current value reaches near zero, that is, the point at which the saturable reactor (lza) comes out of the saturated state (
From t,), the saturable reactor (7g) becomes effective, and the current change rate becomes zero at a small time point (t,). During the time period from time (t,) to time (t,), arc plasma is generated between the electrodes of the breaker (9). In the time period from time point (t,) to time point (t,), the current is near zero and can be considered to be substantially zero. Furthermore, until a certain predetermined time (t4) after time (t,),
Due to the action of the diode (10), the current flowing through the breaker (9) is brought to zero. Then, in the time period from this point (t) to the point (t6), the circuit breaker (?)
The arc plasma generated between the electrodes is attenuated into light and eventually disappears. After time (t4), the current from the capacitor power supply (/2) tries to flow to the breaker (9), but at this time, it cannot flow because the breaker (9) has already been opened. First, the desired cutoff is performed, and the current flowing through the *4di coil (/) flows through the commutation resistor (//), where it is attenuated. Note that the diode (10
) is removed, and if the cutoff fails, the current shown by the dotted line in Figure 2 will not flow, but the movement of the diode (10) realizes complete cutoff. can.

Next, an embodiment of the first invention shown in FIG. 3 will be described.

In Fig. 3, in addition to Fig. 1, the capacitor power supply (l
A reverse voltage detection circuit (/TE) is connected in parallel to the
series circuits are also connected in parallel.

The reverse voltage detection circuit (19) detects the reverse voltage of the capacitor power supply (?), and when this reverse voltage reaches a predetermined excessive value,
In response to this, a discharge command signal is generated to command the switch (20) to close.

To explain the operation of the DC breaker circuit in Fig. 3,
Even after the breaker is activated, the transient current from the capacitor power supply (1) continues to flow through the inductor (13) and commutation resistor (//
), as well as the load coil (/l') and crowbar diode (/6), so after the discharge is complete, the capacitor power supply (l) will start charging in the opposite direction, but the breaker operation is complete. After the reverse charging is started, the reverse Tlj pressure detection circuit (/9) detects a predetermined excessive value, commands the discharge start switch (XO) to close, and connects the discharge resistor (2/) to the capacitor power supply ( /2) in parallel. This forms a discharge path for the capacitor power supply and prevents unnecessary overcharging in the reverse direction. Furthermore, the discharge resistance (2/) also functions as a cutoff resistance together with the cutoff resistance (//).

In addition, in the embodiments of each of the above inventions, a case has been described in which a voltage detection circuit (/7) is provided in parallel with the breaker, but if the jitter generated in the breaker is minute, this voltage detection circuit (/7) can be omitted and the breaker (V) and switch (C) can be operated at the same time.Also, if the load is not a coil but a resistance, the commutation resistance (// ) is no longer necessary.

Furthermore, the inductor (/3) inserted in series with the capacitor power supply usually has stray inductance, so it can be removed depending on the rating of the diode in series with the breaker.

〔Effect of the invention〕

As explained above, in the DC breaker circuit according to the first invention, a saturable reactor is further inserted in the series circuit of the breaker and the diode between the DC power source and the load. When the current change rate is small, the period of substantially zero current is extended, and arc plasma is not generated between the electrodes of the breaker due to the interruption during this period, and the usable period thereof is extended, This has the effect that the cutting operation is reliably performed within a short time and that a large current can be cut off with a small capacity breaker.

Furthermore, in the third invention, after the breaker operation is completed and the capacitor power source starts charging in the reverse direction, an excessive reverse voltage is detected, the discharge start switch is closed, and the discharge resistor is connected in parallel to the capacitor power source. This creates a discharge path for the capacitor power supply, which prevents overcharging in the opposite direction and prevents damage to the capacitor power supply.
It has the effect of assisting the cutting action.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram of a DC breaker circuit according to an embodiment of the first invention, FIG. 2 is a waveform diagram of the circuit breaker current of the above embodiment, and FIG. 3 is an embodiment of the invention. FIG. 4 is a schematic configuration diagram of a conventional known DC breaker circuit, FIG. 1 is a waveform diagram of the breaker current of the conventional example shown in FIG. A schematic configuration diagram of a conventional DC breaker circuit according to the applicant's previous application, and FIG.
3 is a waveform diagram of the breaker current of the DC breaker circuit shown in FIG. (7)...DC power supply, (9)Φ・breaker, (10)・
・Rectifying element, (/2)-φ capacitor power supply, (/3)・
・Inductor, (Ha0#-Nuichi, (/Yu)...Load, (17)...Voltage detection circuit, (tm)@-Saturable reactor, (/q)--Reverse voltage detection circuit, (20)・Discharge start switch, (, 2/) ・Discharge resistor. In each figure, the same symbol indicates the same or equivalent part. 7: ILL electric coolant 9 Breaker 10 Knee 7" diode 12 Container-based power supply 13: Interacts 14: Switch 15: True/False Coil 17: @ Pressure Shiizhi times Kun old ' 吋 く Ya rear shoulder 2 figure t6 Contain '7 @ J艮f + 21L 2yo fu T ￥
) Cut 1za, 1 A τD force 15J and the hood begins b poetry point 3
Figure 15: 5 diagrams with 9 coils +-): (-) current shape L (÷l:
(+) Current S shape when raw (Figure 6, Figure 7)

Claims (7)

[Claims] (1) In a DC or disconnection circuit that disconnects DC current or disconnects it by a disconnector installed between a DC power source and a load, a rectifying element and a saturable device are connected in series with the disconnector. A series circuit of at least a capacitor power supply and a switch connected in parallel to a series circuit of a reactor, a cut-off switch, and a rectifying element, and the above-mentioned switch is closed in relation to an opening command to the cut-off switch. What is claimed is: 1. A direct current or disconnection circuit characterized by comprising a means for making a direct current or disconnection circuit. (2) Claim 1, wherein the closing means is a voltage detection circuit that detects the voltage across the breaker and outputs a signal to close the switch in accordance with the detected voltage. DC and disconnection circuits. (3) The direct current or breaker circuit according to claim 1, wherein the closing means commands the switch to close almost simultaneously with the command to open the shingle breaker. (4) In a DC or disconnection circuit that disconnects DC current or disconnects it using a disconnector installed between a DC power source and a load, a rectifying element and a saturable device are connected in series with the disconnector. A series circuit of at least a capacitor power supply and a switch connected in parallel to a series circuit of a reactor, a cut-off switch, and a rectifying element, and closing the switch in response to an opening command to the cut-off switch. and means for detecting an excessive reverse charging voltage of the capacitor power source and providing a discharge path to the capacitor power source. (5) Claim 4, wherein the closing means is a voltage detection circuit that detects the voltage across the breaker and outputs a signal to close the switch in accordance with the detected voltage. DC and disconnection circuits. (6) The direct current or disconnection circuit according to claim 4, wherein the closing means commands the switch to close almost simultaneously with the command to close the shingle breaker. (7) 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 voltage when detecting the excessive reverse voltage; A direct current or disconnection circuit according to any one of claims 4 to 6, comprising a series body of a bypass switch and a discharge resistor that are connected and closed by the discharge command signal.