JPH0422509Y2 - - Google Patents

Description

[Detailed description of the invention] (Prior art field to which the invention pertains) The present invention relates to a vacuum shear breaker in which peripheral equipment of the vacuum shear breaker is packaged for high-voltage power reception.

[Prior art and its problems]

This type of vacuum cut-off device was developed by the present applicant in a patent application filed in 1983, which integrated a vacuum cut-off switch, a current transformer, and an overcurrent relay into an insulating frame.
Proposed as 104630.

However, this vacuum breaker device has disadvantages in that an ammeter must be provided separately and wiring connections for this must be made outside the device.

[Purpose of invention]

In view of the above-mentioned conventional drawbacks, the present invention eliminates the need to provide a separate ammeter or connect it outside the device.
The purpose of this invention is to obtain a compact and inexpensive vacuum shearing device that is highly packaged.

[Key points of the idea]

The present invention provides a built-in ammeter or a connection terminal for connecting an ammeter to this type of vacuum shearing device, and also has the characteristics required for the current transformer of this vacuum shearing device. Focusing on different points between the power supply circuit and the overcurrent detection circuit of an overcurrent relay, the current transformer has a double core structure that is insulated from each other, and one of the cores is formed to have a structure with a small saturation current. The secondary output formed by the iron core is added to the power supply circuit of the ammeter and overcurrent relay, the other iron core is formed into a structure with a large saturation current, and the secondary output formed by the iron core is added to the power supply circuit of the overcurrent relay. It is characterized in that it is added to the overcurrent and short circuit current detection circuit.

[Embodiments of the invention] Hereinafter, the invention will be explained in detail with reference to embodiments shown in the drawings.

In the embodiment shown in FIG. 1, 1 is an insulating frame in which three vacuum valves are built-in (not shown);
2, 2, 2 and 3, 3, 3 are load-side and power-supply side terminals of the vacuum valve, which penetrate the insulation frame 1 and are drawn out to the outside; 4;
4, 4, 4, 4, 4 are bushes that insulate between the insulating frame 1 and each of the terminals 2, 2, 2 and 3, 3, 3 passing through the insulating frame 1. A feed-through current transformer 5 fixed to an insulating frame 1 fitted into two bushes 4 of the load-side terminals 2 protruding to the outside;
5 through each. Reference numeral 6 denotes a spring-operated handle that is provided on the front surface of the panel 7 and operates the vacuum valves all at once.The vacuum valves can be closed by manually turning on the handle 6. Note that the handle 6 may be operated by an electric spring. 8 is a static overcurrent relay, and this static overcurrent relay 8 is installed in front of the valve 7 so that the time limit and operating current can be set or changed, and a current transformer is installed inside the insulating frame 1. It is connected to the secondary side of 5,5. Reference numeral 9 denotes a rectifier ammeter, and this rectifier ammeter 9 is mounted so that it can be easily read from the front of the panel 7, and is connected to the secondary side of the current transformers 5, 5 inside the insulating frame 1. There is. Reference numeral 10 denotes a tripping coil operated by the overcurrent relay 8, and this tripping coil 10 is attached near the operating shaft 11 and connected to a vacuum valve opening mechanism (not shown).

The vacuum shearing device having the above configuration is installed on an open free-standing panel or a trolley so that it can be operated from the panel 7 side, and the terminals 2, 2, 2 and 3, 3, 3 are connected to each other.
Connect the cable (not shown) on the power source side of the load side with a bolt and nut, set the time limit and current of the overcurrent relay 8, and the overcurrent relay 8 can be used immediately. That is, power is turned on to the load using the handle 6, and when an overload current or fault current flows through the load, the overcurrent relay 8 operates via the current transformers 5, 5, and drives the tripping coil 10 to create a vacuum. The valve opens,
Cut off the current. Further, the load condition during steady operation can be easily read using the ammeter 9.

Next, the operation of this overcurrent relay 8 will be explained in detail using FIG. 3.

In FIG. 3, the area surrounded by the one-dot chain line is an overcurrent relay, and control power is obtained from the DC power supply circuit 13 via the transformer 12 by the secondary current of the current transformer 5. The auxiliary current transformer 14 detects the magnitude of the secondary current of the rectifier 5, which is rectified by the rectifier circuit 15 and becomes an input to the time limit element level detection circuit 16. When the level exceeds the reference level, the time limit signal is transmitted through the time limit circuit 17. With this, the switch circuit 18 operates. The control power obtained by the DC power supply circuit 13 in which the switch circuit 18 operates activates the tripping coil 10 and disconnects the vacuum shield breaker 19. Also, when a large current such as a short circuit current flows,
An instantaneous element level detection circuit 20 connected in parallel with the time-limited element level detection circuit 16 instantaneously operates the switch circuit 18 in a short time of 10 to 40 ms to quickly disconnect the vacuum shield breaker 19.

In addition, in FIG. 3, an ammeter 9 is installed on the secondary side of the current transformer 5.
The overcurrent relay power supply circuit and detection circuit are all connected in series. In this case, the primary current is 10A ~
If the current transformer 5 is a through-type and the primary conductor is one turn when the current transformer is as small as about 40A, the magnetomotive force will be 10AT~
Since it is small at 40 AY, the iron core has to be large to obtain sufficient precision for the current transformer, but if the primary current is approximately 50 A or more, the iron core does not need to be that large.

Next, a different embodiment of the present invention shown in FIG. 2 will be described. In the description of this embodiment, the same components as those of the embodiment shown in FIG. Second
The main difference between the embodiment shown in FIG. 1 and the embodiment shown in FIG.
Since a connecting terminal 21 for connecting an ammeter is provided nearby, this connecting terminal 21 is connected to the secondary side of the alternator 5 inside the insulating frame 1, and normally this connecting terminal 21 is not short-circuited. This prevents the secondary side of the current transformer 5 from being opened due to short-circuiting by the wire. Note that the ammeter is connected by removing the shorting wire.

Next, the operation of the overcurrent relay 8A, which is different from that shown in FIG. 2, and the corresponding current transformer 5A will be explained in detail with reference to FIGS. 4 and 5. This is based on the fact that the characteristics required of the current transformer are different between the ammeter and power supply circuit and the detection circuit. In other words, after the secondary current supplied to the ammeter and the power circuit of the overcurrent relay exceeds a predetermined reference level, it will not increase in proportion to the primary current due to magnetic saturation of the iron core. It is more convenient to have the characteristic that the increase is suppressed.

This is because if a current transformer supplies a secondary current proportional to the primary current over a wide range, when the secondary current supplied from the current transformer exceeds a reference level, the electronic circuit that makes up the overcurrent relay Since the voltage applied to the output voltage becomes an overvoltage, in order to suppress this voltage, it is necessary to provide a Zener diode or a transistor for adjusting the output voltage in the current circuit to bear the overvoltage. This burden is consumed as heat and becomes a loss. Additionally, the ammeter requires a protective device to prevent burnout when an excessive secondary current is supplied. However, if secondary currents exceeding a reference level are automatically suppressed, such protection devices or overvoltage bearing elements become unnecessary.

Therefore, the current transformer for this power supply circuit should preferably have a small saturation current in the iron core and be able to handle a large load.

On the other hand, the overcurrent relay detection circuit needs to accurately detect a wide range of current from the rated load current to the short-circuit current. It is necessary to maintain up to 20 times the current range.

Therefore, it is preferable that the current transformer for the detection circuit has a large iron core saturation current and a load as small as possible.

In this way, the characteristics required for current transformers for power supply circuits and current transformers for detection circuits are all different, but by configuring them with separate iron cores, it is possible to match each current transformer to the required characteristics. The current transformer can be optimally designed and the entire current transformer can be made smaller.

From the above, in this embodiment, the iron core and winding of the current transformer 5A are divided into an ammeter 9, a power supply circuit 22, and a detection circuit 23, as shown in FIG.
Epoxy or Polyester Limix Resin 26
The detection circuit 23 and the secondary side are short-circuited, and the load is minimal, with only the connection wire 25 for short-circuiting. As a result, even if the primary current is as small as 10A to 40A, there is no need to make the iron core that large, and a 5A current transformer can be attached to a vacuum breaker, making it possible to create a structure as shown in Figures 1 and 2. It is. of course,
It is effective even if the primary electric dragon is larger than 50A.

As the ammeter, a rectifier with a low operating VA is used as much as possible, but other digital or liquid crystal types may be used.

[Effect of idea]

As is clear from the above explanation, in the present invention, the vacuum insulation device has a built-in ammeter or a connection terminal for connecting the ammeter, so a dedicated current transformer for measurement is not required. This has the excellent effect of providing a vacuum cutting device that is less expensive, smaller, and more compact.

In addition, the current transformers have a double iron core structure that is insulated from each other, so one can be used to form the power source for the ammeter and overcurrent relay, and the other can be used for the overcurrent and short-circuit current detection circuits. I can do it.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing one embodiment of the present invention;
The figure is a perspective view showing a different embodiment of the present invention, Figure 3 is a block diagram showing the operation of the overcurrent relay of the present invention, and Figure 4 is a block diagram showing an embodiment of the overcurrent relay different from that in Figure 3. , FIG. 5 is a sectional view of a current transformer corresponding to the overcurrent relay shown in FIG. 4. 1... Insulating frame, 2... Terminal, 3... Terminal, 4... Bush, 5,5A... Feedthrough current transformer, 6... Handle, 7... Panel, 8... Static overcurrent relay , 9... Rectifier ammeter, 10...
Output coil, 11... Operating shaft, 12... Transformer, 13... DC power supply circuit, 14... Auxiliary current transformer, 15... Rectifier circuit, 16... Time limit element level detection circuit, 17... Time limit circuit , 18...Switch circuit, 19...Vacuum shield breaker, 2...Momentary element level detection circuit, 21...Connection terminal, 22, 23...
...each divided iron core, 25...connection wire,
26...Insulating material.

Claims (1)

[Scope of utility model registration request] A vacuum breaker device that integrates a vacuum breaker, a current transformer, and an overcurrent relay into an insulating frame and has a built-in ammeter or a connection terminal for connecting the ammeter. , the current transformer has a double iron core structure that is insulated from each other, one of the iron cores is formed to have a structure with a small saturation current, and the secondary output formed by the iron core is used as a power source for an ammeter and an overcurrent relay. In addition to the circuit, the other iron core is formed to have a structure with a large saturation current, and the secondary output formed by the iron core is applied to an overcurrent and short circuit current detection circuit of an overcurrent relay. Vacuum cutting device.