JPS60240019A - Power breaker - 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 [Object of the Invention] (Industrial Application Field) The present invention relates to a power circuit breaker, particularly a high voltage DC circuit breaker.

In particular, breaking high voltage circuits is not easy compared to alternating current circuits.

Therefore, as a measure to provide a blocking ability, a blocking method as shown in FIG. 1 has been proposed. In this method, a high-voltage generating section B, such as an element (3) having a power storage function such as a capacitor, is connected in parallel to a current-carrying disconnection section A, such as a cass breaker (2), which is connected in series to a current-carrying circuit (1). Then, the energized circuit (1) is cut off in the manner described below.

That is, in response to the opening command S, 1) the energization/disconnection section A is activated at time t in FIG. When the electrodes (2) begin to open, an arc occurs between the electrodes (2), and the arc voltage increases over time as the electrode spacing increases over time, as shown in FIG. 2(d). Then, the capacitor (3) of high voltage generating section B has
As shown in Figure 2 (0), a current 3 equal to [temporal increase rate (dv/clt) x capacitance value] of the arc voltage flows as shown in the figure, and the energizing circuit (1 ) starts commutation from the energizing/disconnecting section A to the high voltage generating section B. Therefore, the current flowing through the electrode (2) gradually decreases as shown in FIG. 2(b). When the current - flowing through the high voltage generating section B reaches the circuit current circuit (see Fig. 11) at time t1,
As shown in Figure 2 (b), the current flowing through electrode (2) becomes zero, the arc generated between electrodes (2) disappears, and the current flows between electrodes (2).
The dielectric strength between the two is restored.

Meanwhile, during this period, the capacitor (3) of the high voltage generating section B stores electricity due to the commutated current, and when the stored voltage reaches the circuit voltage vs shown in FIG. 2(d) at time t2, the commutated current (2) becomes zero as shown in FIGS. 2(c) and (a), and the circuit (1) is cut off.

(Problems with the prior art) By the way, in order to ensure reliable disconnection using this conventional method, the capacitance of the capacitor (3) of the high voltage generating section B must be calculated as (circuit current ■/temporal increase rate of arc voltage dv/ d,
t ) or more, and the larger the capacitance value, the more convenient it is for interrupting. However, since high-voltage capacitors are generally expensive, it is desirable to keep the capacitance value as low as possible in order to suppress increases in the price of circuit breakers. In order to achieve this, for example, the opening speed of the electrode (2) of the current carrying/disconnecting section A may be increased to increase the temporal increase rate dv/d,t of the arc voltage. However, there are inherent limitations determined by the type of energizing/disconnecting section A used.

Another method is to apply an external magnetic field to the arc, or to apply liquefied sulfur hexafluoride (SF) to the arc.
It is also possible to spray an insulating medium such as 6) and use these to disturb the arc and change the arc voltage instantaneously, but this would require fairly complex accessory equipment. Therefore, the cost of the circuit breaker tends to increase.

[Structure of the invention]

(Means and effects for solving the problem) The present invention is based on the following idea: Even if the arc voltage remains unchanged, if the voltage applied to the capacitor is suddenly changed to 3-, the arc voltage can be suddenly reduced. This was done based on the idea that the same effect could be obtained by changing the capacitance, and that a large current could be commutated from the current disconnecting section to the capacitor with a small capacitance.To achieve this, the following steps were taken. It is characterized by taking the measures explained in the following.

That is, as shown in the circuit diagram of one embodiment shown in Fig. 3 (same symbols as in Fig. 1 indicate equivalent parts), a voltage exceeding a specific operating voltage is connected in series with the capacitor (3) of the high voltage generating section B. Connect a cut-off energizing part D, for example, a gap (4), which has the function of suddenly energizing only when a voltage is applied, and this gap (
4) The present invention is characterized in that current is applied through the capacitor (3) by the voltage that appears when the electrode (2) of the current-carrying/disconnecting section A begins to open.

In this way, time t in FIG. electrode (2
) is the arc voltage based on the opening of the pole at time t.

The operating voltage of the gap (4) at ■□. When the current is applied in the above state, the terminal voltage of the capacitor (3) changes rapidly. Therefore, as shown in Figure 4(b),
4- The current flowing through the electrode (2) 4 cuts off to zero, and the fourth
As shown in the figure (cl), the current is instantaneously commutated to the circuit of the capacitor (3).
) stores electricity, and its terminal voltage rises as shown in Figure 4(d) and reaches circuit voltage ■8 at time t2.
As shown in Figure 4 (0), the current of capacitor (3) ■3
Therefore, the circuit current ■ is cut off.

(Effects of the Invention) As described in 2 below, in the present invention, since the voltage applied to the capacitor (3) changes abruptly, the change in voltage is caused by an arc of 7, compared to the case where it is continuously applied. becomes significantly larger. Therefore, it is possible to instantaneously commutate a large current using a capacitor (3) having a small capacitance.

The present invention has been described above with reference to one embodiment, but the gap (
Instead of 4), a Zener diode or a thyristor can also be used for I). If the electromagnetic or electrostatic energy of the circuit is large, an energy absorbing part E, for example a zinc oxide element, is connected in parallel to the series circuit of the gap (4) and the capacitor (3), as shown by the dotted line in FIG. You can connect a non-linear resistor such as

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram of a conventional circuit breaker, Fig. 2 is a time characteristic diagram of current and terminal voltage of the breaker to explain its operation, Fig. 5 is a circuit diagram of an embodiment of the present invention, and Fig. 4 is a circuit diagram of a conventional circuit breaker. The figure is a time characteristic diagram of current and terminal voltage of the circuit breaker to explain its operation. A: Current carrying/disconnecting section, B: High voltage generating section, S
...Opening command, (1)...Circuit, (2)...
...Electrode, (3)...Capacitor, D...
Cutting current carrying part, (4)...gap, E...energy absorption part. Patent applicant: Patent attorney representing the Central Research Institute of Electric Power Industry
Otsuka 1 off-campus person 7-

Claims (1)

[Claims] A high voltage generation section consisting of a capacitor is connected in parallel with the current carrying disconnection section, and the arc voltage caused by the opening of the current carrying disconnection section causes the flowing current of the current carrying disconnection section to be commutated to the high voltage generating section, and the capacitor is In a power circuit breaker which performs interruption by generating a circuit voltage having a magnitude capable of interrupting commutation current and a stored voltage of opposite polarity, the above-mentioned energizing disconnection section is connected in series with the above-mentioned high voltage generation section. A cut-off current-carrying section such as a gap that suddenly becomes conductive when the terminal voltage reaches a specified value is provided, and the current in the current-carrying disconnection section is selectively and instantaneously diverted to the high-voltage generating section. Features of power circuit breakers.