JPH0442899Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] This invention connects the secondary sides of two transformers connected in parallel to a low-voltage distribution line using a single-phase three-wire V-connection by operating a push button switch. The present invention relates to a switching connection device on the secondary side of a transformer that automatically switches connection to either 3-phase 3-wire or 3-phase 4-wire with V connection.

[Prior art] For example, the primary sides of two transformers installed in parallel on a low-voltage distribution line as a construction power source are connected, and the secondary sides are connected to each other depending on the purpose of the load, such as single-phase 3-wire, V
Power is supplied to the load by connecting to either a 3-phase 3-wire connection or a 3-phase 4-wire connection.

By the way, in such construction transformers,
Conventionally, for example, when switching the wiring system on the secondary side of a transformer depending on the type of load, an operator manually connected the secondary side of the transformer to either single-phase three-wire wiring or V-connection three-phase three-wire wiring.
It was designed to be connected to either 3-phase 4-wire wire or V-connection.

[Problems that the invention aims to solve] However, when the secondary side of the transformer is switched and connected manually by workers, the work requires a lot of effort and time, and it is difficult to change the load type during the process. If the wiring system has to be changed due to the above reasons, the connection work on the secondary side of the transformer must be redone, resulting in poor workability. In addition, if the wiring method is incorrect when changing the wiring on the secondary side of a transformer, an overcurrent may flow to the load or the transformer itself may be a cause of an accident, causing problems in terms of safety and reliability. Ta.

Therefore, with the present invention, the connection on the secondary side of a transformer can be easily and easily switched by operating a push button switch, and the connection on the secondary side of a transformer is always in phase with the secondary side of the other transformer. It is an object of the present invention to provide a switching connection device for the secondary side of a transformer that is highly safe and reliable and can connect an electric circuit in this manner.

[Means for Solving the Problems] In order to achieve the above-mentioned purpose, the present invention has a switching system provided in the lines corresponding to each of the three phases derived from the secondary side of the transformer and the neutral line, respectively. It has contacts and push button switches corresponding to single-phase 3-wire, 3-phase 3-wire with V connection, and 3-phase 4-wire with V connection, and when a switching command is received by pressing any of these push buttons, each of the above switching is performed. A switching device that switches the secondary side of the transformer to either single-phase 3-wire, 3-phase 3-wire with V-connection, or 3-phase 4-wire with V-connection by turning on/off contacts, and connected to an input terminal. a switch connected to an output terminal, the switch being connected to an output terminal and being switchable to either an in-phase fixed contact connected to the in-phase fixed contact or a reverse-phase fixed contact connected in a reverse phase to the in-phase fixed contact; When the secondary voltage of the other transformer is applied to the input terminal, the voltage difference between the voltage applied from this input terminal and the secondary voltage of the other transformer applied to the output terminal is detected. The in-phase/out-of-phase discrimination unit determines whether the secondary side of one transformer and the secondary side of the other transformer are connected in the same phase, and the in-phase/out-of-phase discrimination unit determines whether the secondary side of the transformer If it is determined that they are connected in the same phase, the logic output operates the switch so that it is connected to the fixed contact on the in-phase side, and the in-phase/reverse-phase determining section determines that they are not connected in the same phase. and an in-phase detection and closing device having a closing operation unit that operates the switch to connect to the negative phase side fixed contact based on the logic output thereof.

[Function] In the switching connection device on the secondary side of the transformer having such a configuration, simply by operating the push button switch, the line and neutral line corresponding to each of the three phases derived from the secondary side of the transformer can be connected. The switching contacts installed on the line are turned on and off by the switching device to switch to either single-phase 3-wire, 3-phase 3-wire with V-connection, or 3-phase 4-wire with V-connection, so that the secondary side of the transformer Connection switching is simple and easy, and when connection switching is performed and the secondary voltage of the transformer is applied to the input terminal connected to the fixed contact on the in-phase side, the voltage applied from this input terminal and the switch The differential voltage between the secondary side voltage of the other transformer and the secondary side voltage of the other transformer applied to the output terminal of the transformer is detected by the in-phase/out-of-phase discrimination section, and the secondary side of the transformer and the secondary side of the other transformer are connected in the same phase. If the in-phase/out-of-phase determining unit determines that the secondary sides of the transformer are connected in the same phase, the logic output is given to the closing operation unit to fix the switch to the in-phase side. When the switch is operated so that it is connected to the contact, and the in-phase/reverse-phase discriminator determines that it is not connected in the same phase, the logical output is given to the closing operation section, and the switch is connected to the reverse-phase side fixed contact. The connected operation ensures that the secondary sides of the transformers are turned on in phase, making them safer and more reliable.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows an example of the overall configuration of a switching connection device on the secondary side of a transformer according to the present invention. In FIG. 1, 1 is a construction transformer whose primary side voltage can be switched by a tap changer 2, and the primary side terminals tu, tv, and tw of this transformer 1 are connected to a low-voltage distribution line.
Further, lines Lu, Lv, Mw and N corresponding to each of the three phases and a neutral line are led out from the secondary side of the transformer 1 via a no fuse breaker (NFB) 3. 4 is each of these lines Lu,
The connection method for Lv, Mw and N is single-phase 3-wire (1Φ3W), 3-phase 3-wire with V connection (V-3Φ3W)
This switching device 4 switches to 3-phase 4-wire (V-3Φ4W) with V connection, and this switching device 4 is for each line Lu,
Switching contacts Su, Sv provided at Lv, Mw and N,
Single-phase 3-wire (1Φ3W) that provides on/off commands for Sw and Sn, 3-phase 3-wire with V connection (V-3Φ3W)
and a push button switch 5 corresponding to 3-phase 4-wire (V-3Φ4W) with V connection, and this push button switch 5
When a switching command is issued by the operation of -3Φ3W and V-
It can be switched to either 3Φ4W connection. In this case, the neutral line N and line Lv are connected to the changeover switch S1.
This makes it possible to ground, for example, a case that is at ground potential. That is, when the push button switch 5 corresponding to 1Φ3W is operated, the switching contacts Su, Sv, and Sn are closed as shown in FIG. 2A, and the switching contact Sw is closed.
is operated to the open state, and the neutral line N is grounded by the changeover switch S1.
Also, when the push button switch 5 corresponding to V-3Φ3W is operated, the switching contacts Su and
Sv and Sw are closed and the switching contact Sn is opened, and the line Lv is grounded by the switch S1. Furthermore, V-
When the push button switch 5 corresponding to 3Φ4W is operated, the changeover contacts Su, Sv, Sw and Sn are operated to the closed state as shown in Fig. 2c, and the changeover switch S is operated.
1, the line Lv is grounded.
The switching contacts Su, Sv, Sw and Sn are shown in Figure 2a.
As a control means for controlling pattern switching as shown in c to c, a microcomputer may be used to perform software processing, and switching the switching contact to the open or closed state in the three switching patterns is a switching process. Focusing on the contacts Sw and Sn and the changeover switch S1, we made them correspond to three switching patterns in advance to control the on/off control of the energizing path between the excitation coil and the power source, for example, on the operating section that operates these contacts. It may be something. On the other hand, 6a and 6b are railroad tracks
Output and line of switching device 5 corresponding to Lu and Lv
There are two in-phase detection and input devices to which the outputs of the switching device 5 corresponding to Lu and Mw are specifically added. Since these two in-phase detection/input devices 6a and 6b have exactly the same configuration and function, the line Lu
The in-phase detection and input device 6a to which the outputs from the switching device 5 corresponding to and Lv are applied will be described in detail with reference to FIG. In Fig. 3, an in-phase side fixed contact Sa to which the output from the switching device 5 corresponding to the lines Lu and Lv is applied through the input terminal ti, and an anti-phase side fixed contact connected in an opposite phase to this in-phase side fixed contact Sa. The transformer has a switch S2 which is operated to close any one of the transformers Sb, and this switch S2 is connected to an output terminal to which is connected to a secondary line of the other transformer (not shown). In addition, the primary winding side of the transformer Tr is connected to the output terminal to, and the switch S2 is connected to the secondary winding side of the transformer Tr.
An in-phase side drive unit Ca for closing the in-phase side fixed contact Sa and an anti-phase side drive unit Cb for closing the opposite-phase side fixed contact Sb are connected in parallel, and each parallel circuit has an in-phase, Contacts SA and SB are provided that close in response to a close command from the negative phase discrimination section. Furthermore, a common mode detector is connected to one side of the input terminal ti.
One input terminal of the in-phase detector Da is connected, and one of the output terminals to is connected to the other input terminal of the in-phase detector Da. Similarly, one input terminal of a negative phase detector Db is connected to one of the output terminals to, and the other input terminal ti is connected to the other input terminal of the negative phase detector Db. These in-phase detector Da and negative-phase detector Db detect the voltage difference between the voltage level applied from the input terminal ti and the voltage level applied from the output terminal ti, respectively, and when the difference voltages have a predetermined relationship, the logic It outputs signals of "1" and "0". The outputs of the in-phase detector Da and the anti-phase detector Db are mutually input to AND circuits ANDa and ANDb each having a negative terminal, and when the logic conditions are satisfied, the contacts Sa and Sb are connected to each other. A close command is now given to the These in-phase detectors Da,
Negative phase detector Db and AND circuit ANDa, ANDb
constitutes an in-phase/out-of-phase discriminator.

Next, the operation of the switching connection device on the secondary side of the transformer configured as described above will be described.

For example, the connection switch on the secondary side of the transformer is V-
When you operate push button switch 5 corresponding to 3Φ3W,
A switching command is given from this push-button switch 5 to a control section (not shown), and the control signal causes the contact operation section to operate, and the switching contacts Su, Sv, Sw, and Sn and the switching switch S1 are placed in the state shown in FIG. 2b. Become,
The secondary side connection of the transformer 1 is switched and connected to V-3Φ3w. When the secondary side connection of the transformer 1 is switched to V-3Φ3w by the switching device 4 in this way, a switching contact is connected to the input terminal ti of one of the in-phase detection and closing devices 6a.
Voltage is applied through Su and Sv. Now, assuming that the secondary side of transformer 1 is connected in phase with the secondary side of the other transformer, a voltage of 200 V, for example, is applied to one input terminal of the in-phase detector Da shown in Fig. 3. At the same time, the same voltage as above is applied to the other input terminal through the output terminal to. Therefore, in this common mode detection Da, when the difference voltage becomes 0, a logic "1" signal is input to one input terminal of the AND circuit ANDa, and a logic "0" signal is input to the negative terminal. be done. In addition, one input terminal of the negative phase detection Db is connected to the output terminal to.
When a voltage of 200V is applied and a voltage of 0V is applied to the other input terminal, the difference voltage becomes 200V, so a logic "0" signal is input to one input terminal of the AND circuit ANDb. , a logic "1" signal is input to the negative terminal. As a result, the logical condition of the AND circuit ANDb is not satisfied, but the logical condition of the AND circuit ANDa is satisfied, so the contact SA is closed by the command from the AND circuit ANDa. And this contact
When SA is closed, the in-phase drive unit Ca is excited, and the switch S2 is closed to the in-phase fixed contact Sa. In this case, the transformer Tr is excited in advance by the secondary output from the other transformer input through the output terminal to.

Next, assuming that the secondary side of transformer 1 is connected in reverse phase to the secondary side of the other transformer, one input terminal of the in-phase detector Da shown in FIG.
A voltage of 0V is applied to the other input terminal through the output terminal to. Therefore, in this common mode detector Da, the difference voltage is 200V.
As a result, a logic "0" signal is input to one input terminal of the AND circuit ANDa, and a logic "1" signal is input to the negative terminal. Also,
The voltage applied to both input terminals of the negative phase detector Db is 0V
Then, the difference voltage becomes 0V, and the AND circuit
A logic "1" signal is input to one input terminal of ANDb, and a logic "0" signal is input to the negative terminal. As a result, the logical condition of the AND circuit ANDa is not satisfied, but the logical condition of the AND circuit ANDb is satisfied, so the contact SB is closed by the command from the AND circuit ANDb. When this contact SB closes, the negative phase side drive coil Cb is excited, and the switch S2 is connected to the negative phase side fixed contact Sb. As a result, the secondary side of the transformer 1 is connected to the secondary side of the other transformer. This means that the in-phase connection is made to the side.

The above is the operation of one common-mode detection and closing device 6a, but also for the operation of the other common-mode detection and closing device 6b, the voltage applied to the input terminal ti is the voltage obtained through the other phase voltage, that is, the switching contacts Su and Sw. The only difference is that the voltage is applied, and the closing operation is performed so that the connection between the secondary side of the transformer 1 and the secondary side of the other transformer is in the same phase as described above.

In addition, in the above description, the secondary side connection of the transformer 1 is V-
In the case of 3Φ3W, 1Φ3W shown in Figure 2 a,
In the case of switching to V-3Φ4W shown in FIG. 3C, the closing operation is performed so that the connection between the secondary side of the transformer 1 and the secondary side of the other transformer is in the same phase as described above.

In this way, in this example, 1Φ3W, V-
By simply operating any of the push button switches 5 corresponding to 3Φ3W and V-3Φ4W, the lines Lu, Lv, Mw corresponding to each of the three phases derived from the secondary side of the transformer 1 can be changed.
and switching contacts Su, Sv, provided on the neutral line N.
Sw and Sn and the changeover switch S1 are turned on and off by the switching device 4 to switch to either single-phase 3-wire, 3-phase 3-wire with V connection, or 3-phase 4-wire with V connection, so that the secondary side of the transformer Connection switching can be performed simply and easily. In addition, when the connection is switched and the secondary voltage of the transformer 1 is applied to the input terminal ti of the switch S2, which is provided to be able to switch to either the in-phase fixed contact Sa or the negative-phase fixed contact Sb, this input terminal The difference voltage between the voltage applied from ti and the secondary voltage of the other transformer when applied to the output terminal to connected to switch S2 is detected by in-phase and negative-phase detectors Da and Db.
detects and determines whether the secondary side of one transformer and the secondary side of the other transformer are connected in the same phase, and it is determined that the secondary sides of the transformer are connected in the same phase. The contact provided in the closing operation section is determined by the logic output from the AND circuit ANDa.
SA is closed and the switch is operated so as to be connected to the fixed contact Sa on the in-phase side, and when it is determined that the in-phase connection is not made, the logic output from the AND circuit ANDb is used to connect the switch to the closing operation section. Since the switch S2 is connected to the negative phase side fixed contact Sb by closing the contact SB, the secondary side of the transformer is reliably turned on in the same phase, resulting in high safety and reliability. Become something.

[Effects of the invention] As described above, according to the invention, by simply operating the push button switch of the switching device, the lines connected to the lines corresponding to each of the three phases derived from the secondary side of the transformer and the neutral line can be changed. Switching of the connection on the secondary side of the transformer is simple and easy, as the switching contacts are turned on and off to switch to single-phase 3-wire, 3-phase 3-wire with V-connection, or 3-phase 4-wire with V-connection. Also, when connection switching is performed and the secondary voltage of the transformer is applied to the input terminal connected to the fixed contact on the in-phase side, the voltage applied from this input terminal and the output terminal connected to the switch are The voltage difference between the secondary side voltage of the other transformer that is applied is detected by the in-phase/out-of-phase discrimination section, and it is determined whether the secondary side of the transformer and the secondary side of the other transformer are connected in the same phase. If the in-phase/out-of-phase determining unit determines that the secondary sides of the transformer are connected in the same phase, the cooking output is applied to the input operation unit and the switch is connected to the fixed contact on the in-phase side. When the in-phase/out-of-phase determining section determines that the connections are not in phase, the logic output is given to the closing operation section so that the switch is connected to the out-of-phase fixed contact. This ensures that the secondary sides of the transformers are turned on in the same phase, thereby providing a highly safe and reliable switching connection device for the secondary sides of the transformers.

[Brief explanation of the drawing]

Fig. 1 is a circuit configuration diagram showing an embodiment of a switching connection device on the secondary side of a transformer according to the present invention, and Figs. FIG. 3 is a circuit diagram showing the details of the in-phase detection and closing device in the same embodiment. 1...Transformer, 4...Switching device, 5...Push button switch, 6a, 6b...In-phase detection and closing device, Lu,
Lv, Mw...3-phase lines, N...neutral line,
Su, Sv, Sw, Sn...Switching contact, ti...Input terminal, to...Output terminal, Sa...In-phase side fixed contact,
Sb...Reverse phase side fixed contact, S2... Switch, Da...
...In-phase detector, Db...Negative-phase detector, ANDa,
ANDb...AND circuit, Tr...Transformer, Ca, Cb
...In-phase side, opposite-phase side drive coil, SA, SB...Contact.

Claims (1)

[Scope of utility model registration request] The secondary sides of two transformers connected in parallel to a low-voltage distribution line are connected to each other according to the purpose of the load: single-phase 3-wire, 3-phase 3-wire with V-connection, or 3-phase 4-wire with V-connection. In a system that supplies power to a load from a common line on the secondary side of both transformers, lines corresponding to each of the three phases derived from the secondary side of one of the transformers and a neutral line are provided respectively. It has switching contacts and pushbutton switches corresponding to single-phase 3-wire, 3-phase 3-wire with V-connection, and 3-phase 4-wire with V-connection, and when a switching command is received by pressing any of these pushbutton switches, each of the above-mentioned a switching device for switching the secondary side of the transformer to either single-phase 3-wire, 3-phase 3-wire with V-connection, or 3-phase 4-wire with V-connection by operating a switching contact; A switch connected to the output terminal and connected to the output terminal, the switch being connected to either the connected in-phase fixed contact or the reverse-phase fixed contact connected in reverse phase to the in-phase fixed contact; When the secondary voltage of the switched transformer is applied to the input terminal, the voltage difference between the voltage applied from this input terminal and the secondary voltage of the other transformer applied to the output terminal is detected. The in-phase/out-of-phase discrimination unit determines whether the secondary side of one transformer and the secondary side of the other transformer are connected in the same phase, and the in-phase/out-of-phase discrimination unit determines whether the secondary side of the transformer When it is determined that the two sides are connected in the same phase, the logic output operates the switch so that it is connected to the fixed contact on the in-phase side, and the in-phase/reverse-phase discriminator determines that the two sides are not connected in the same phase. and an in-phase detection and closing device having a closing operation section that operates the switch to connect to a fixed contact on the negative phase side based on a logical output thereof. Device.