JPS58121515A - Opening and closing device - 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] Technical field of invention The present invention relates to a switching device that is an improved switching control device.

Technical background of the invention and its problems In general, switching devices such as circuit breakers, load switches, and disconnectors have a new phenomenon called current flow, in which the current is forcibly cut off before the current zero point at the time of cutoff, but the delay is small. If this current interruption occurs during current interruption, an overvoltage will occur. However, there is no need to worry too much about overvoltage due to simple current interruption. However, in recent years, research into the phenomenon of switching surges has progressed, and it has become clear that in addition to overvoltage due to current interruption, the following switching surge phenomenon exists, albeit in very rare cases.

That is, at the current zero point, the insulation recovery between the breaker and the poles is unable to withstand the transient voltage applied between the poles, and the circuit breaker re-ignits, and as this re-ignition is repeated, the voltage gradually increases, resulting in a voltage build-up phenomenon. In addition, when 3 phases are cut off by finger operation, if one phase is cut off at the current zero point and restarts, causing a voltage build-up phenomenon, the current is forcibly cut off in the other phases as well, which is unique to the switchgear. This causes a phenomenon that causes a current cut-off larger than the cut-off current value of the current, so-called three-phase simultaneous cut-off phenomenon.

Normally, in a power transmission system, a large-capacity ratio-shear accelerator whose function is to supply phase-lag capacity is installed in parallel, and instead of a synchronous phase modifier, the phase modifier is used alone or together with a power capacitor. Generally, this reactor is a three-phase reactor, connected in a Δ or Y manner, connected directly to the grid or to the tertiary side of a transformer, and turned on and off as appropriate.

When cutting off the small delayed current flowing through the accelerator, there is a risk that the three-phase simultaneous cutting-off phenomenon described above may occur.

Therefore, in a conventional switching device such as a circuit breaker, a circuit breaker is connected to each phase of a three-phase line, and each phase circuit breaker is operated by a three-phase finger by an operating device. Taking an example of an electric spring operating device (not shown), this operating device compresses and stores a drive spring via a coupling mechanism by a motor that is driven by a command from a control device that will be described later. The drive spring is released immediately after it is most compressed.

When the drive spring starts to release, the main shaft connected to the interrupting section of the breaker main body is operated via another coupling mechanism section to perform the interrupting or closing operation. Such a shutoff or closing operation is performed for each phase, and is operated by a three-phase finger by the control device. The control circuit of this conventional control device is constructed as shown in FIG. The shutoff operation will now be explained. A push button switch (3) with one side connected to a positive polarity DC power supply P and the other connected to a negative polarity DC power supply N via the contact excitation coil (1) and the other contact part (2) When you press , the excitation coil (1
) is energized, and the normally open contacts (4) and (5) are closed and self-maintained. Although the contact portion (2) is a normally open contact, it is in a closed state during a cutoff operation.

In addition, the normally open contact (5) closes, and the normally open contacts (6-1), (6-2), (6-3) of each phase (
7-1), (7-2).

(, 7-3), the respective motors (6-1), (6-2), and (6-3) start driving simultaneously by the DC power supply PN.

Note that normally open contacts (7-1), (7-2), (7-3)
It is in a closed state during cutoff operation.

In this way, each motor (6-1), (6-2)
(6-3), when the three-phase drive device (not shown) performs a cutoff operation due to finger operation, the first phase is re-ignited as described above, and high-frequency current flows to the other two phases. When they are superimposed, a current zero point is forcibly created, causing a three-phase simultaneous cutoff phenomenon and generating a switching surge overvoltage, which could threaten the insulation of lines and equipment.

OBJECTS OF THE INVENTION The present invention has been made in consideration of the above points, and its purpose is to provide a switching device that prevents the three-phase simultaneous cut-off phenomenon caused by the three-phase finger-operated cut-off operation. It is in.

Summary of the Invention The present invention opens the second and third phase switches after a set time delay after the first phase switch opens, thereby preventing the three-phase simultaneous cutoff phenomenon. This is its characteristic.

Embodiment of the Invention An embodiment of the present invention will be described below with reference to the drawings. Second
In the figure, a cut-off operation circuit and a make-on operation circuit are connected in parallel between the DC power supplies PN, and the part numbers with A attached in the figure indicate the system of the make-on operation circuit, and the others indicate the cut-off operation circuits. However, the motor is connected to both systems.

The cutoff and on-off command circuit θυ, (IIA) is connected in parallel between the DC power supply PN. Cutoff command circuit (1υ is the pushbutton switch α that commands the cutoff and the excitation coil θ
The normally open contact (i) and the contact circuit (1) can be connected in series.The normally open contact αD connected to the excitation coil 0 is connected in parallel to the push button switch (l'jJ). In addition, the contact circuit part (IQ is a normally open contact (16-1), (1
6-2) and (16-3) are connected in parallel, and at the time of commanding the cutoff operation, they are in the closed state, so all normally open contacts (16-1) and (16-2) are connected in parallel.
, (16-3) is in a closed state. Further, dotted lines indicate states in which they are interlocked.

In addition, the cutoff and closing motor drive circuit Qf9. (1
8 people) respectively motors (19-1), (19-2),
(19-3) is connected in parallel between DC power supplies PN. A cutoff motor drive circuit (li is a normally open contact wire, a cutoff motor circuit (21), and a motor (19) that drives each phase, respectively.
-1), (19-2), (19-3) are DC power supplies P
Connected between N. , and the cut-off motor circuit, υ is a normally open contact (from the 20 connection points @ to the motor (19-1)
, (19-2), and (19-3).

The connection point (24 is connected to the motor (24) via the normally open contact (18-1)
19-1), and also connected to the motor (19-2) via the timer (2) and the normally open contact (18-2),
Furthermore, the timer (2 power) is connected to the motor (19-3) via the normally open contacts (18-3).The second phase timer C4 is connected to the motor (19-3) through the normally open contacts (1s-g) of the first phase. After that, the normally open contact (18-2) of the second phase is set to close after a delay of, for example, several milliseconds, and the normally open contact (18-2) of the third phase is still closed. After closing, the normally open contact (18-3) is set to close with a delay.

Next, the effects of the above-mentioned opening/closing device of the present invention will be explained.

A pushbutton switch (1
When you press 4, the excitation coil (1) is energized, the normally open contact OD is closed and self-holding, and at the same time the normally open contact (21
is closed, still normally open contact (18-1).

(1B-2) and (18-3) are already closed. Since the normally open contact (18-1) is closed, the motor (19-1) is driven.
20 is closed and the first phase is driven, a timer (c) causes the second phase motor (19-
2) is driven, and after a delay of a set time, the third phase motor (19-3) is driven by the timer 04).

Since the structure of the operating device for each phase of the switchgear is completely the same, the one operated by the motor (19-1)
Phase is cut off first, motor (19-2), (19-3
) The other two phases operated by timers (c) and H are operated with a delay of the time set by timers (c) and H, respectively, and are opened.

Therefore, when a slow-phase current flows through an inductive device, after the first phase switchgear is completely opened, the other two phase switchgears are opened with a delay, resulting in three-phase simultaneous shutoff. This phenomenon does not occur and opening/closing surges can be prevented.

Next, a switchgear according to another embodiment of the present invention will be described with reference to FIG. 3, in which the same parts as in FIG. 2 are denoted by the same reference numerals. The first phase of the cutoff motor circuit is connected from the connection point (20) to the first motor (19-1) via the normally open contact (18-1).A timer is connected between the connection point (21) and the connection point (2υ). t
26) is connected, branched from the connection point (25), enters the second phase motor (19-2) from the normally open contact (18-2), and the third phase enters the normally open contact (18-3). From the motor (19-
3). Further, this timer (26) is set to operate the second phase and the third phase simultaneously after a set time delay of several milliseconds after the first phase operates.

In addition, normally open contacts (18-1), (18-2), (1
8-3) are all closed during the cutoff operation.

With this configuration, the normally open contact (2υ) closes in response to the cutoff command, and the first phase motor (19-1
) is driven, the timer 0 is delayed by the set time.
0 drives the second and third phases simultaneously. Therefore, after the first phase is opened, the second and third phases are opened with a delay, so a three-phase simultaneous cutoff phenomenon does not occur, and the occurrence of switching surge overvoltage can be prevented.

As described in detail, according to the switching device of the present invention, in the cutoff operation, after the motor of the one-phase operating device is driven and opened, the motors of the other two phases are activated after a set time delay. By installing a timer in the control device that drives the phase current, when the slow phase current is cut off, the current flowing to the other phases is forcibly cut off due to the re-ignition caused by the cutoff of one phase, which is the so-called simultaneous three-phase cutoff phenomenon. It is possible to prevent insulation breakdown of the system due to the occurrence of switching surge overvoltage.

[Brief explanation of drawings]

Fig. 1 is a control circuit diagram of a conventional switchgear, Fig. 2 is a control circuit diagram of a switchgear according to an embodiment of the present invention, and Fig. 3 is a control circuit diagram of a switchgear according to another embodiment of the present invention. be. (1υ, (IIA)... cutoff and make-on command circuit,
04...Push button switch, Qi...Excitation coil,
tti... Normally closed contact, aQ... Contact circuit section, (16
-1), (16-2), (16-3), 悄, 121
3, (18-1), (18-2). (18-3)... Normally open contact, 081, (18A)... Cutting off and closing motor drive circuit, Cυ, (21A)... Cutting off and closing motor circuit, (19-1), (19- 2), (19-3)
...Motor, (t2, (25)-MH point, ('
3 s G") 9 (2b) ... p timer. Agent Patent attorney Inoue - Male': 1p4i Figure 2 Figure 3

Claims (3)

[Claims] (1) In a switchgear consisting of switches connected to each phase of a three-phase circuit, after the first phase switch opens, the second and third phase switches open after a set time delay. A switchgear characterized in that the poles are opened. (2) A timer set at a time later than the motor driving the first phase is connected to the electric circuit including the motor that drives the operating mechanism of the second phase and the third phase. 2. The switching device according to claim 1, wherein the third phase is opened by driving each motor individually. (3) A timer set at a time later than that of the motor driving the first phase is connected all together to the electric circuit including the motors that drive the operating mechanisms of the second and third phases, and The switching device according to claim 1, which opens the phase and the third phase by driving them simultaneously.