JPH0950741A - Self-excited commutation type dc circuit breaker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance a disconnecting characteristic and reduce the capacitance of the main parallel capacitor of a first commutation circuit by providing a second commutation circuit having a parallel-connected auxiliary capacitor in a DC circuit breaker to abruptly change an arc voltage. SOLUTION: A second commutation circuit of an auxiliary capacitor 6 is connected in parallel with a first commutation circuit comprising the series body of a min parallel reactor 2 and a main parallel capacitor 3 connected in parallel with a DC circuit breaker 1. The oscillation of a frequency specified by the capacitance of the capacitor 6 is superimposed on the frequency of the oscillation of a current and a voltage specified by the reactor 2 and the capacitance of the capacitor 3, and an arc voltage is abruptly changed and an arc current is made to cause a magnified oscillation, thereby making it feasible to disconnect a direct current. In the case of disconnecting a DC current of the same level as the conventional one, the capacitance of the main parallel capacitor of the first commutation circuit can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a commutation circuit in a self-excited commutation type DC circuit breaker for cutting off the direct current of a power system.

[0002]

2. Description of the Related Art FIG. 5 shows "The Institute of Electrical Engineers of Japan, Power and Energy Division Conference 1994 (Paper II)" No. 621 p. 824, p.
It is a block diagram which shows the general self-excited commutation type | mold DC interruption apparatus shown on page 825. In the figure, a self-excited commutation type DC circuit breaker includes a DC circuit breaker 1, a parallel reactor 2 and a parallel capacitor 3 which form a commutation circuit, and a parallel capacitor 3 and a parallel reactor 2 for absorbing an overvoltage of the parallel capacitor 3. It is composed of a surge absorber 4 and a DC line 5 of a power system connected in parallel. The surge absorber 4 may simply be connected in parallel to the parallel capacitor 3.

FIG. 6 is a sectional view showing a main part of a self-excited commutation type DC circuit breaker, showing a case where a puffer type gas circuit breaker is used. Reference numeral 1 denotes a DC circuit breaker, which has a fixed contact 11 and a movable contact 12 for passing a DC current. Reference numeral 2 denotes a parallel reactor, one end of which is connected to the fixed contact 11 of the DC circuit breaker 1. A parallel capacitor 3 has one end connected to the other end of the parallel reactor 2 and the other end connected to the movable contact 12 of the DC circuit breaker 1. An insulating nozzle 14 is fixed to the movable contact 12 together with the puffer cylinder 13. A piston rod 15 is directly connected to the movable contact 12, and this rod is pulled out and moved by an operating mechanism 16. 1
Reference numeral 7 is a fixed puffer piston, and 18 is an opening. The SF6 gas in the interior surrounded by the movable contact 12, the puffer cylinder 13, and the puffer piston 17 is ejected when the pressure is increased and is blown to the arc 19. Reference numeral 20 is a fixed-side lead conductor connected to the fixed contact 11, and 21 is a movable-side lead conductor connected to the movable contact 12.

Next, the operation will be described. In the puffer type gas circuit breaker, when the operating mechanism 16 pulls out the piston rod 15, the fixed contact 11 and the movable contact 12
Is opened and an arc 19 is generated between both contacts. Then, the SF6 gas in the puffer cylinder 13 is pressurized by the puffer piston 17 and is sprayed from the opening 18 to the jet arc 19. However, in the case of direct current, unlike the alternating current, the current zero point does not cross periodically, so it is difficult to cut off even if SF6 gas is blown to the direct current arc as it is. Therefore, by connecting the parallel reactor 2 and the parallel capacitor 3 in parallel to the DC circuit breaker 1, the current is commutated in the commutation circuit, while the parallel reactor 2 and the parallel capacitor 3 and the mutual negative voltage-current characteristics of the SF6 arc are connected. By the action, the arc voltage current oscillation is expanded to form a current zero point, and the SF6 gas boosted by the puffer piston 17 is ejected from the opening 18 so that the insulating nozzle 1
The arc 19 is blown from 4 to extinguish the arc.

[0005]

In a self-excited commutation type DC interruption device, a commutation circuit having a parallel reactor and a parallel capacitor for expanding and oscillating an arc current to perform commutation plays an important role. From the viewpoint of cost, there is a demand to reduce the capacity of this parallel capacitor as much as possible.
Further, in order to rapidly expand and oscillate the arc current, it is necessary to rapidly change the arc voltage. The present invention has been made to solve the above problems, and while reducing the capacitance of the parallel capacitor, by rapidly changing the arc voltage, the arc current is rapidly expanded and oscillated to generate a direct current. The purpose is to obtain a self-excited commutation type DC interruption device for interruption.

[0006]

A self-excited commutation type DC circuit breaker according to claim 1 of the present invention is a DC circuit breaker for interrupting energization of DC in a power system, and a main circuit connected in parallel to this DC circuit breaker. In a self-excited commutation type DC circuit breaker comprising a first commutation circuit having a parallel capacitor and a main parallel reactor, and a surge absorber for the parallel capacitor, a second circuit having an auxiliary capacitor connected in parallel to the DC circuit breaker. It has a flow circuit.

According to a second aspect of the present invention, there is provided a self-commutated commutation type DC circuit breaker, which is a DC circuit breaker for interrupting energization of DC in a power system, a main parallel capacitor and a main parallel reactor connected in parallel to the DC circuit breaker. In a self-excited commutation type DC circuit breaker comprising a first commutation circuit having a series body of the above and a surge absorber of the parallel capacitor, a series body of an auxiliary capacitor and an auxiliary reactor connected in parallel to the DC circuit breaker. And a second commutation circuit having According to a third aspect of the present invention, there is provided a self-excited commutation type DC circuit breaker, in which a DC circuit breaker for interrupting DC of a power system, a main parallel capacitor connected in parallel to the DC circuit breaker and a main parallel reactor are connected in series. In a self-excited commutation type DC circuit breaker comprising a first commutation circuit having a body and a surge absorber of the parallel capacitor, a second commutation circuit having an auxiliary capacitor connected in parallel to the DC circuit breaker; It is provided with a third commutation circuit having a series body of an auxiliary capacitor and an auxiliary reactor connected in parallel to the DC breaker.

According to a fourth aspect of the present invention, in the self-excited commutation type DC interruption device, the capacity of the auxiliary capacitor is smaller than the capacity of the main parallel capacitor. According to a fifth aspect of the present invention, in a self-excited commutation type DC circuit breaker, a DC circuit breaker is provided with a fixed contact and a movable contact for energizing DC, and an SF generated in an arc generated between the contacts when the contact is opened.
It is a puffer type gas circuit breaker having a puffer piston for blowing 6 gases and an insulating nozzle.

[0009]

The self-excited commutation type DC interruption device according to claim 1, claim 2 and claim 3 of the present invention has an auxiliary capacitor in addition to the first commutation circuit having the main parallel capacitor and the main parallel reactor. Since a commutation circuit or a commutation circuit having a series body of an auxiliary capacitor and an auxiliary reactor is provided,
Because the frequency of the current-voltage oscillation specified by the main parallel capacitor and the capacity of the main parallel reactor is superimposed on the vibration of the frequency specified by the capacity of the auxiliary capacitor or the capacity of the series body of the auxiliary capacitor and the auxiliary reactor, The arc voltage fluctuates more drastically, and this causes the arc current to rapidly expand and vibrate, interrupting the direct current. Therefore, to cut off the same level of DC current as before,
The main parallel capacitor capacity of the commutation circuit can be reduced.

In the self-excited commutation type DC interruption device according to claim 4 of the present invention, since the capacity of the auxiliary capacitor is smaller than the capacity of the main parallel capacitor, it is defined by the capacity of the main parallel capacitor and the main parallel reactor. Due to the superposition of the high-frequency vibration defined by the auxiliary capacitor of smaller capacity or the series combination of the auxiliary capacitor of smaller capacity and the auxiliary reactor, the arc voltage fluctuates more drastically. , With this as a trigger, the arc current is rapidly expanded and oscillated to cut off the direct current. Therefore, the main parallel capacitor capacity of the first commutation circuit can be reduced in order to cut off the same level of DC current as the conventional one. Further, since the self-excited commutation type DC circuit breaker according to claim 5 of the present invention uses the puffer type gas circuit breaker, the reliability associated with actual results can be obtained.

[0011]

【Example】

Embodiment 1 FIG. Embodiments of a self-excited commutation type DC interruption device of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the self-excited commutation type DC interruption device of the present invention.
In the figure, 1 is a DC circuit breaker, which is a puffer type SF6 gas circuit breaker. Reference numeral 2 is a main parallel reactor, 3 is a main parallel capacitor, and a series body of the main parallel reactor 2 and the main parallel capacitor 3 is connected in parallel to the DC circuit breaker 1 to form a first commutation circuit of the DC circuit breaker 1. are doing. A surge absorber 4 is connected in parallel to the main parallel capacitor 3 and the main parallel reactor 2 in order to absorb the overvoltage of the main parallel capacitor 3. The surge absorber 4 may simply be connected in parallel to the parallel capacitor 3. Reference numeral 5 is a DC line. An auxiliary capacitor 6 is connected in parallel to the first commutation circuit and constitutes a second commutation circuit of the DC circuit breaker 1. The details of the puffer-type SF6 gas circuit breaker have the same configuration as in FIG.

Next, the operation will be described. DC breaker 1
When the fixed contact 11 and the movable contact 12 which are energized with the DC current are opened, an arc 19 is generated between the contacts (see also FIG. 5 for the reference numeral). Since the main parallel reactor 2 and the main parallel capacitor 3 are connected in parallel to the DC circuit breaker 1, current is diverted to the first commutation circuit while the main parallel reactor 2, the main parallel capacitor 3 and the SF6 arc are connected. By the interaction of the voltage-current negative characteristic of, the arc voltage-current oscillation is expanded to form a current zero point, and SF6 gas is blown to the arc to extinguish it. This DC circuit breaker 1
Since the second commutation circuit having the auxiliary capacitor 6 connected in parallel to the first commutation circuit is provided in the, the frequency of current-voltage oscillation defined by the capacities of the main parallel capacitor 3 and the main parallel reactor 2 is set. Since the vibration of the frequency defined by the capacity of the auxiliary capacitor 6 is superimposed, the arc voltage fluctuates more drastically, and this can be used as a trigger to rapidly expand the arc current to interrupt the direct current. .

At this time, if the capacity of the auxiliary capacitor 6 is made smaller than that of the main parallel capacitor 3, the frequency defined by the capacity of the auxiliary capacitor 6 becomes higher frequency vibration, and the vibration is the main parallel capacitor 3. And the frequency of current-voltage oscillation specified by the capacity of the main parallel reactor 2,
Since they are superposed, the arc voltage fluctuates more drastically, and with this as a trigger, the arc current can be immediately expanded and oscillated to interrupt the direct current. In FIG. 1, there is only one second commutation circuit having the auxiliary capacitor 6, but the third commutation circuit having the auxiliary capacitor, the fourth commutation circuit, and so on are connected in parallel to the first commutation circuit. It may be provided in.

Example 2. FIG. 2 is a configuration diagram showing another embodiment of the self-excited commutation type DC interruption device of the present invention. In the figure, the same reference numerals as those used above denote the same or corresponding parts, and the same applies hereinafter. Reference numeral 7 is an auxiliary reactor, 8 is an auxiliary capacitor, and a series body of the auxiliary reactor 7 and the auxiliary capacitor 8 is connected in parallel to a series body of the main parallel reactor 2 and the main parallel capacitor 3. A series body of the auxiliary reactor 7 and the auxiliary capacitor 8 constitutes a second commutation circuit of the DC breaker 1.

Next, the operation will be described. DC breaker 1
Since a second commutation circuit having a series body of the auxiliary reactor 7 and the auxiliary capacitor 8 connected in parallel to the first commutation circuit is provided in the, the capacity of the main parallel capacitor 3 and the main parallel reactor 2 is increased. Since the vibration of the frequency specified by the capacities of the auxiliary capacitor 8 and the auxiliary reactor 7 is superimposed on the frequency of the specified current-voltage oscillation, the arc voltage fluctuates more drastically, and this promptly expands the arc current. It is possible to vibrate and cut off the direct current.

At this time, the capacities of the auxiliary capacitor 8 and the auxiliary reactor 7 are changed to the main parallel capacitor 3 and the main parallel reactor 2.
If it is made smaller than the capacitance of the above, the frequency defined by the capacitances of the auxiliary capacitor 8 and the auxiliary reactor 7 becomes higher frequency vibration, and the vibration is defined by the capacitances of the main parallel capacitor 3 and the main parallel reactor 2. Since it is superimposed on the frequency of the current-voltage oscillation, the arc voltage fluctuates more drastically, and this can be used as a trigger to rapidly expand the arc current and interrupt the direct current. In FIG. 2, the number of the second commutation circuit having the series body of the auxiliary reactor 7 and the auxiliary capacitor 8 is only one, but the third commutation circuit having the series body of the auxiliary reactor and the auxiliary capacitor, the fourth commutation circuit Similarly, a commutation circuit, ----- may be provided in parallel with the first commutation circuit.

FIG. 3 is a diagram showing the relationship between the breaking current i0 in the DC circuit breaker 1, the capacitance C of the capacitor, and the capacitance L of the reactor. When the auxiliary capacitor C2 is further connected in parallel to the first commutation circuit having the series body of the main parallel reactor L1 and the main parallel capacitor C1, the current is shared, so that not only the cutoff current i0 increases, Since the frequency of vibration increases, the optimum value of the capacity of the main parallel reactor decreases from LP1 to LP2. That is, the capacity of the main parallel reactor is reduced, and the reactor can be made compact. Further, since the breaking current increases, the capacity of the main parallel capacitor can be reduced.

Also, when the auxiliary reactor (7 in FIG. 2) L2 is connected, the vibration frequency increases, and the optimum value LP of the capacity of the main parallel reactor decreases, so that the capacity of the main parallel reactor decreases and the size becomes compact. You can Of course, since the current is shared, the breaking current also increases. The capacity of the auxiliary capacitor of the second commutation circuit of FIGS. 1 and 2 is preferably smaller than the capacity of the main parallel capacitor, and the capacity is 1 / the capacity of the main parallel capacitor.
2, preferably 1/10 or less.

Embodiment 3 FIG. FIG. 4 is a constitutional view showing still another embodiment of the self-excited commutation type DC interruption device of the present invention.
In the figure, 9 is an auxiliary reactor and 10 is an auxiliary capacitor. The series body of the auxiliary reactor 7 and the auxiliary capacitor 8 is connected in parallel to the series body of the auxiliary reactor 2 and the auxiliary capacitor 3 to form a second commutation circuit of the DC circuit breaker 1. Similarly, the series body of the auxiliary reactor 9 and the auxiliary capacitor 10 constitutes a third commutation circuit, and the auxiliary capacitor 6 constitutes a fourth commutation circuit. In this way, one or a plurality of series bodies of the auxiliary reactor and the auxiliary capacitor and one or a plurality of the auxiliary capacitors 6 may be connected in parallel. When a plurality of auxiliary capacitors 6 or 8 are provided,
The capacitor capacity of the second commutation circuit can be made smaller than that in the case of one auxiliary capacitor 6 or 8.

When a 550 kV class puffer type gas circuit breaker is used and the DC breaking current value is 3500 A class,
The main parallel reactor connected to this circuit breaker as the first commutation circuit should have a capacity of 200 to 600 μH and the main parallel capacitor should have a capacity of 10 to 25 μF. At that time, the auxiliary capacitor should have a capacity of the main parallel capacitor. 1/2 of
It is desirable to set it to 1/10 or less. When the auxiliary capacitor is not connected, the capacity of the main parallel capacitor is larger and 18 to 49 μF is required.

[0021]

As described above, according to the self-excited commutation type DC interruption device of the first, second and third aspects of the present invention, the first switching device having the main parallel reactor and the main parallel capacitor is provided. Since a commutation circuit having an auxiliary capacitor or a commutation circuit having a series body of an auxiliary reactor and an auxiliary capacitor is provided in addition to the current circuit, it is possible to obtain a direct-current interruption device having high interruption performance. Further, the capacity of the main parallel capacitor of the first commutation circuit can be reduced.

According to the self-excited commutation type DC circuit breaker of the present invention, since the capacity of the auxiliary capacitor is smaller than the capacity of the main parallel capacitor, the capacity of the main parallel capacitor and the main parallel reactor is reduced. Since the high-frequency vibration specified by the auxiliary capacitor with smaller capacity or the series body of the auxiliary capacitor with smaller capacity and auxiliary reactor is superimposed on the specified frequency of current-voltage oscillation, the arc voltage becomes more severe. It fluctuates, and with this as a trigger, the arc current is rapidly expanded and oscillated, and the direct current is cut off. Therefore, the main parallel capacitor capacity of the first commutation circuit can be reduced in order to cut off the same level of DC current as the conventional one. Further, according to the self-excited commutation type DC circuit breaker of the fifth aspect of the present invention, since the puffer type gas circuit breaker is used, the reliability associated with the actual results can be obtained.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a self-excited commutation type DC interruption device of the present invention.

FIG. 2 is a configuration diagram showing another embodiment of the self-excited commutation type DC interruption device of the present invention.

FIG. 3 is a diagram showing a relationship between a breaking current, a capacitance of a capacitor, and a capacitance of a reactor according to the present invention.

FIG. 4 is a configuration diagram showing still another embodiment of the self-excited commutation type DC interruption device of the present invention.

FIG. 5 is a configuration diagram showing a conventional self-excited commutation type DC interruption device.

FIG. 6 is a cross-sectional view showing a configuration of a main part of a conventional self-excited commutation type DC interruption device.

[Explanation of symbols]

1 DC breaker 2 Main parallel reactor 3 Main parallel capacitor 4 Surge absorber 5 DC line 6 Auxiliary capacitor 7 Auxiliary reactor 8 Auxiliary capacitor 9 Auxiliary reactor 10 Auxiliary capacitor 11 Fixed contact 12 Movable contact 19 Arc

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Hiroki Ito 8-1-1 Tsukaguchihonmachi, Amagasaki City Mitsubishi Electric Co., Ltd. Itami Works (72) Inventor Takayoshi Moriyama 8-1-1 Tsukaguchihonmachi, Amagasaki Mitsubishi Electric Co., Ltd. Itami Works (72) Inventor Kenji Kamei 8-1-1 Tsukaguchi Honcho, Amagasaki City Mitsubishi Electric Co., Ltd. Itami Works (72) Inventor Hamano Suenobu 8-1-1 Tsukaguchi Honmachi, Amagasaki Mitsubishi Electric Itami Manufacturing Co., Ltd. (72) Inventor Takeshi Yonezawa 8-1-1 Tsukaguchi Honcho, Amagasaki City Mitsubishi Electric Co., Ltd. Itami Manufacturing (72) Inventor Naoaki Takeji 3-3-22 Nakanoshima, Kita-ku, Osaka, Osaka Electric Power Company (72) Inventor Koji Takahata Marunouchi 2-5, Takamatsu City, Kagawa Prefecture Shikoku Electric Power Company (72) Inventor Masayuki Hatano Kyoto Chuo-ku, Ginza 6-chome 15th No. 1 power development in the Corporation

Claims (5)

[Claims] 1. A direct current circuit breaker for interrupting energization of direct current in a power system, a first commutation circuit having a main parallel capacitor and a main parallel reactor connected in parallel to the direct current circuit breaker, and a surge absorber for the parallel capacitor. A self-excited commutation type DC circuit breaker comprising a second commutation circuit having an auxiliary capacitor connected in parallel to the DC circuit breaker. 2. A first commutation circuit having a direct current circuit breaker for interrupting the direct current of a power system, a series body of a main parallel capacitor and a main parallel reactor connected in parallel to the direct current circuit breaker, and the parallel capacitor. In the self-excited commutation type DC circuit breaker including the surge absorber, a second commutation circuit having a series body of an auxiliary capacitor and an auxiliary reactor connected in parallel to the DC circuit breaker is provided. Excited commutation type DC breaker. 3. A first commutation circuit having a DC circuit breaker for interrupting the direct current of a power system, a series body of a main parallel capacitor and a main parallel reactor connected in parallel to the DC circuit breaker, and the parallel capacitor. A self-commutated commutation type DC circuit breaker including a surge absorber, and a second commutation circuit having an auxiliary capacitor connected in parallel to the DC circuit breaker,
A self-excited commutation type DC circuit breaker comprising a third commutation circuit having a series body of an auxiliary capacitor and an auxiliary reactor connected in parallel to the DC circuit breaker. 4. The self-excited commutation type DC interruption device according to claim 1, wherein the capacity of the auxiliary capacitor is smaller than the capacity of the main parallel capacitor. 5. The DC circuit breaker is a puffer type gas circuit breaker having a fixed contact and a movable contact for passing a DC current, a puffer piston for blowing SF6 gas to an arc generated between the contacts at the time of opening, and an insulating nozzle. The self-commutated commutation type DC interruption device according to any one of claims 1 to 4.