JP3048015B2 - Construction bypass switch with trip device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a construction bypass switch with a trip device for switching from a construction bank to a sound bank.

[0002]

2. Description of the Related Art As shown in FIG. 9, when a transformer TrB of a bank B is exchanged, a low voltage side of a bank A and a low voltage side of the bank B are connected by a bypass switch 40 in the conventional method. After that, the power detection and phase detection are performed, and if normal, the low-voltage bypass switch 40 is turned on. Then, the primary cutout PC of the B bank is opened to exchange the transformer TrB of the B bank.

[0003]

However, the transformer TrA of the bank A is 50 kvA, the tap voltage of the transformer TrA is 200 V, while the transformer TrA of the bank B is
B is 20 kvA, and the tap voltage of this transformer TrB is 22 kVA.
If the voltage is 0 V, a load current flows from the bank B to the load D on the bank A when the bypass switch 40 is turned on. This is because the transformer TrB on the B bank side tends to have a large load as the load sharing because the tap voltage on the B bank side is higher than the tap voltage on the A bank side. However, in this case, since the capacity of the transformer TrB on the bank B side is small, the load current becomes an overload current, and the transformer TrB is burned out or the primary cutout PC
Fuse may be melted. For this reason,
There is a problem that bank switching cannot be performed reliably.

Therefore, when performing normal bank switching, it is a fact that the tap voltages of the transformers TrA and TrB of both banks are measured or checked in a ledger.

SUMMARY OF THE INVENTION It is an object of the present invention to enable the bank to be switched so that when the bypass switch is turned on, the overload current flows and the bypass switch can be opened to protect the transformer and the primary cutout. An object of the present invention is to provide a bypass switch for construction with equipment.

[0006]

In order to achieve the above object, a first aspect of the present invention is a construction with a trip device for connecting low-voltage sides of both banks by a connection cable and switching one bank to the other bank. In the bypass switch, overload current detection means for detecting an overload current of the transformer in the one bank, and determination means for determining that an overload current has flowed based on a detection signal of the overload current detection means. A transmitting unit that transmits a command signal when the determining unit determines that an overload current has flowed, a receiving unit that receives a command signal from the transmitting unit, and a construction based on the command signal received by the receiving unit. And an opening drive means for opening the bypass switch.

According to a second aspect of the present invention, there is provided an injecting means for injecting a command signal output from a transmitting means to a low-pressure side of a bank, and a receiving input means provided on the low-pressure side of the bank to input the command signal to a receiving means. The gist is to have

[0008]

With the above arrangement, the load current of the transformer in the construction bank is detected by the overload current detection means, and the determination means determines whether the overload current is flowing based on the detection signal. When the determination means determines that the overload current has flowed, the transmission means transmits a command signal, and the reception signal receives the command signal. Then, based on the command signal, the opening drive means opens the bypass switch.

A command signal output from the transmitting means is injected into the connection cable by the injection means, and the command signal is input to the receiving means via the receiving input means.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. As shown in FIGS. 1 and 5, distribution lines U, V, and W are provided with banks A and B, respectively. The description of the A bank will be described below. In the configuration of the B bank, the same components will be denoted by the same reference numerals and description thereof will be omitted.

[0011] Primary cutout PCUs, PCs provided for the respective distribution lines U, V, W corresponding to each phase.
A pair of transformers Tr1 and Tr2 are connected via V and PCW. A load D is provided on the low voltage side of the transformers Tr1 and Tr2.

The transformers Tr1 and Tr2 are V-connected.
Two output terminals P, C1 and C2 are provided. Further, a middle point between the output terminals C1 and C2 is grounded to form a ground terminal N.

Therefore, a line voltage of 100 V can be taken out from the output terminal C1 or the output terminal C2 and the ground terminal N, and can be supplied to the load D of a general household. Further, a line voltage of 200 V can be extracted from the output terminal P and the output terminal C1 or the output terminal C2, and can be supplied to a load D such as a factory.

A three-phase four-wire bypass switch 1 is connected to the low-voltage side of both banks A and B via connection cables LA, LB, LC and LN. A power detector / phase detector 3 is connected to the bypass switch 1 via a control line 2.

The bypass switch 1 includes a pair of fixed electrodes opposed to each other corresponding to each phase, and movable electrodes DU, DV, DW, DN for closing or opening the pair of fixed electrodes.
And a drive circuit 4 for driving the movable electrodes DU, DV, DW, DN. Thus, the drive circuit 4 can automatically open and close the bypass switch 1, and can also manually open and close the bypass switch 1.

Next, the configuration of the drive circuit 4 provided inside the bypass switch 1 will be described in detail. As shown in FIG. 2, MC2 is a second relay, which is energized by a control signal from the power detector / phase detector 3. The second relay MC2 is configured to open and close only the movable electrode DN, and to control the opening and closing of the second contact 5 of the a contact.

MC1 is a first relay, which is connected in series with the second contact 5. The first relay MC1 opens and closes the movable electrodes DU, DV, and DW, and contacts the first contact 6 of the a contact connected to the second relay MC2 and the a contact that drives the closing display circuit (LED) 7. The third contact 8 is controlled to open and close.

Reference numeral 9 denotes a metal outlet provided in the bypass switch 1, and one end of the control line 2 is connected to the metal outlet 9. L1 to L4, R1 to R
Reference numeral 4 denotes output lines connected to the output terminals P, C1, C2, and N of both banks, respectively, which are connected to a plurality of connection terminals t provided in the metal outlet 9, respectively.
The drive circuit 4 is also connected to the connection terminal t of the metal outlet 9.

Next, the configuration of the voltage detector / phase detector 3 will be described in detail. As shown in FIG. 3, reference numeral 10 denotes a metal outlet provided in the power detector / phase detector 3, to which the other end of the control line 2 is connected. Reference numeral 11 denotes a power detection / phase detection circuit, which is connected to a plurality of connection terminals t provided on the metal outlet 10.

Therefore, the voltages and phases from both the A and B banks are input via the output lines L1 to L4, R1 to R4 and the control line 2. Therefore, the power detection and phase detection circuit 11 performs power detection and phase detection, and
It is determined whether or not can be inserted.

Reference numeral 12 denotes a forced lock release switch provided in the power detection / phase detection circuit 11, which is configured to perform forced power transmission when there is no voltage on the load side. That is, the switch is used when used in the same manner as a conventional bypass switch. Reference numeral 13 denotes an LED provided in the power detection / phase detection circuit 11, which is turned on when the forcible lock release switch is turned on.

Reference numeral 15 denotes a power detection / phase detection display circuit provided in the power detection / phase detection circuit 11, which indicates whether the power detection / phase detection is normal. Reference numeral 16 denotes a buzzer connected to the voltage detection / phase detection display circuit 15, which informs, for example, an abnormality by sound. Reference numeral 14 denotes a test switch provided in the voltage detection / phase detection circuit 11 for checking whether the voltage detection / phase detection circuit 11 operates normally.

Reference numeral 17 denotes a power supply contact provided in the power detection / phase detection circuit 11, which is turned on by the control of the power detection / phase detection circuit 11 when the power detection / phase detection is normal. ing.

VSD1 and VSD2 are 100V or 20V
This is a voltage switch that switches the voltage to 0V. That is,
Since the voltage detection / phase detection circuit 11 and the carrier reception circuit 21 are for 100V, the voltage detection / phase detection circuit 11 and the carrier reception circuit 21 are switched to the power detection / phase detection circuit 11 and the carrier reception circuit 21 by the switching operation of the voltage switches VSD1 and VSD2.
0 V is not applied.

The voltage switch VSD1 is connected to power input lines D1 and D2 connected to a signal line connecting the connection terminal t and the power detection / phase detection circuit 11, and an output line L3 on the A bank side. , L4 supply power to the power detection and phase detection circuit 11. Reference numeral 20 denotes the voltage switch VSD1 and the
A power switch that supplies power to the phase detection circuit 11. Further, the voltage switch VSD2 is connected to signal input lines N1 and N2 connected to a signal line connecting the connection terminal t and the voltage detection / phase detection circuit 11.

Therefore, the voltage switch VSD2 receives a command signal, which will be described later, from the output lines R3 and R4 on the B-bank side via the control line 2 so as to receive signal input lines N1 and N1 as reception input means.
It flows through N2. The voltage switch VSD2 supplies power to the carrier receiving circuit 21.

Numeral 21 denotes a carrier receiving circuit as receiving means connected to the voltage switch VSD2, which receives a command signal from an overload detector 22, which will be described later, on the signal input line N1,
It is to be received via N2. Reference numeral 23 denotes a drive contact provided as an open drive means provided in the carrier receiving circuit 21, and is turned on when power is supplied from the voltage switch VSD2. As shown in FIG. 1, when the carrier receiving circuit 21 receives a command signal from the overload detector 22, the driving contact 23 is turned off by the carrier receiving circuit 21.

Reference numeral 24 denotes the drive contact 23, the power supply contact 1
7 and connected in series so that the drive circuit 4 of the bypass switch 1 can be driven by the switch 24 so that the switch 1 can be closed. Has become.

Reference numeral 25 denotes an open switch of a contact b connected to the drive contact 23. By opening the open switch 25, the bypass switch 1 can be manually opened. The configuration of the vessel 22 will be described in detail.

As shown in FIG. 4, 26 is an overload detector 2
2 is a carrier transmitting circuit as a transmitting means provided inside, and is configured to carry a command signal to a carrier receiving circuit 21 of the power detector / phase detector 3. CT1 and CT2 are current transformers as overload current detecting means attached to the connection cables LA and LC of the B bank, and are connected from the transformers Tr1 and Tr2 of the B bank to the load D side of the A bank. ,
An overload current is detected from flowing from the transformers Tr1 and Tr2 on the A bank side to the load D side on the B bank. The current transformers CT1 and CT2 are connected to the carrier transmission circuit 2
6 respectively.

27a and 27b are the current transformers CT1 and CT
2 is a comparison circuit as a discriminating means connected to each of them. The comparison circuits 27a and 27b are connected to the current transformers CT1 and CT1.
The detection signal from CT2 is compared with a preset threshold value. That is, when the current transformers CT1 and CT2 detect an overload current, the comparison circuits 27a and 27b output an output signal.

An OR circuit 28 is connected to the comparison circuits 27a and 27b.
The output signal from is input. 29 is a transport drive circuit connected to the OR circuit 28,
A command signal of a predetermined frequency (50 kHz in this embodiment) is generated. Usually, several tens of k
A high frequency command signal of Hz is generated and used.

30a, 30b are connection cables LC, LN
A signal injector as an injection means connected to the connection cable L.
C, LN, and carries a command signal to the carrier receiving circuit 21 of the power detector / phase detector 3 via the bypass switch 1, the control line 2, and the signal input lines N1, N2. Note that power is supplied to the overload detector 22 from the connection cables LC and LN by the signal injectors 30a and 30b.

Reference numeral 31 denotes an a-contact, which is turned on when the carrier transmission circuit 26 is driven, and is turned off when an overload current flows.

Reference numeral 32 denotes a code reel,
The drive contact 23 of the carrier receiving circuit 21 in the phase detector 3 and the drive contact 31 of the overload detector 22 are connected in parallel. Therefore, when the drive contact 23 of the carrier reception circuit 21 is not opened or closed by the command signal of the carrier transmission circuit 26, the bypass switch 1 can be opened and closed by turning on and off the drive contact 31 in the carrier transmission circuit 26. I have.

The operation of the construction bypass switch with a trip device configured as described above will be described. First, B
When replacing the transformers Tr1 and Tr2 of the bank (construction bank), the bypass switches 1 in the open state are connected to the low voltage sides of the A bank (healthy bank) and the B bank by connecting cables LA, LB, LC, and LN. Connect through. And
The control line 2 is connected to the metal sockets 9 and 10 of the bypass switch 1 and the voltage detector / phase detector 3.

The current transformers CT1 and CT2 are attached to the low voltage side of the bank B or the connection cables LA and LC, respectively.
The signal injectors 30a and 30b are attached to C and LN, respectively.

On the other hand, as shown in FIG.
Output lines L1 to L4, R1 to R4 connected for each phase
Accordingly, the voltage value and phase angle of each phase are input to the power detection / phase detection circuit 11 of the power detection / phase detector 3 via the control line 2. Also,
The power from the voltage switch VSD2 is supplied to the carrier receiving circuit 21. Then, the carrier transmitting circuit 26 and the carrier receiving circuit 2
After confirming that transmission / reception is possible with the device 1, the drive contact 23 in the carrier receiving circuit 21 is turned on and the drive contact 31 in the carrier transmitting circuit 26 is turned on. Thereby, 30a and 30
b can detect a connection error.

When the power switch 20 is turned on,
The power detection / phase detection circuit 11 performs the power detection / phase detection of the banks A and B, determines whether the bank can be switched, displays the result on the power detection / phase detection display circuit 15, and when the bank can be switched, The power supply contact 17 is turned on.

When the closing switch 24 is turned on in this state, the second contact MC2 of the drive circuit 4 is excited because the drive contact 23 and the power supply contact 17 are in the on state. The movable electrode DN is turned on by the excitation of the second relay MC2, and the second contact 5 is turned on. Then, when the second contact 5 is turned on, the first relay MC1 is excited, the movable electrodes DU, DV, DW are turned on, and the first contact 6 and the third contact 8 are turned on. As a result, the closing display circuit 7 is driven to indicate that the bypass switch 1 has been closed.

Then, the primary cutout PCU, PCV, and PCW of the B bank are released in order, and the transformer T
Exchange r1 and Tr2. Thereafter, the primary cutout PCU, PCV, and PCW are sequentially input again.

Next, to open the bypass switch 1, the opening switch 25 is turned off. Thereby, the first relay M
Since C1 is demagnetized, the movable electrodes DU, DV, DW are opened, the first contact 6 and the third contact 8 are turned off, the closing display circuit 7 cancels the closing display, and the second relay MC
2 is demagnetized, so that the movable electrode DN is opened. As a result, since the opening of the bypass switch 1 is completed, the bank construction is completed by removing the connection cables LA, LB, LC, and LN of the banks A and B, respectively.

When the bypass switch 1 is turned on when the tap voltages of the two banks are different and an overload current flows through at least one of the connection cables LA and LC on the B bank side, the current transformers CT1 and CT1 are turned on. CT2 detects this overload current.

As shown in FIG. 4, comparison circuits 27a and 27b in the carrier transmission circuit 26 apply detection signals of the current transformers CT1 and CT2 to a predetermined threshold value (for example, 150 mA of the rated current).
%), It is determined that an overload current has flowed if the load current exceeds this threshold, and an output signal “1” is output to the OR circuit 28. When the output signal “1” is input from one of the comparison circuits 27 a and 27 b to the OR circuit 28, the OR circuit 28 outputs a driving signal to the transport driving circuit 29 and turns off the driving contact 31. To

The transport drive circuit 29 injects a 50 kHz command signal into the connection cables LC and LN by the signal injectors 30a and 30b based on the drive signal. Then, this command signal is transmitted to the connection cables LC, LN and the output lines R3, R
4, received by the carrier receiving circuit 21 via the control line 2, the signal input lines N1 and N2, and the power switch VSD2.

The carrier receiving circuit 21 turns off the drive contact 23 based on this command signal, so that the first relay MC1 and the second relay MC2 are demagnetized, respectively, and the movable electrode D
U, DV, DW, and DN open. Further, since the first to third contacts 5, 6, 8 are turned off, the closing display circuit 7 cancels the closing display.

As a result, the transformers Tr1 and T
Since the overload current does not continue to flow through r2, the transformer Tr
1, Tr2 burnout, primary cutout PCU,
Fusing of PCV and PCW can be prevented. Therefore, the bypass switch 1 is turned on particularly when the tap voltages are different, and the bypass switch 1 is immediately opened when an overload current flows. Out PCU, PCV, PCW can be protected.

Further, since the overload detector 22 determines whether or not the bank can be switched, it is not necessary to confirm with a ledger and measure the tap voltage, unlike the related art, so that the bank construction can be performed quickly.

In addition to opening the bypass switch 1 by the carrier transmission circuit 26 and the carrier reception circuit 21, the code reel 32 is connected in parallel with the drive contact 31 of the carrier transmission circuit 26 and the drive contact 23 of the carrier reception circuit 21. It is also possible to use it. In this case, the bypass switch 1 can be opened by turning off the drive contact 31.

In the present embodiment, a command signal is injected into the connection cables LC and LN at a predetermined frequency, and the bypass switch 1 is opened by the command signal. It is also possible to configure so that the vessel 1 is opened.

As shown in FIG. 6, a signal injection current transformer CT3 for command signal injection is attached only to the connection cable LN of the bank B, and a signal reception current transformer CT4 for command signal reception is connected to the connection cable LN. Attach. In this case, when an overload current flows, the command signal from the transport drive circuit 29 is
N, this command signal is transmitted to the signal receiving current transformer C
When T4 is received, the bypass switch 1 can be automatically opened by the command signal.

FIG. 7 shows still another embodiment, in which an oscillation circuit 35 is provided in place of the carrier drive circuit 29 of the overload detector 22, and a radio wave is provided in the power detector / phase detector 3 in place of the carrier reception circuit 21. A receiving circuit 36 is provided. In this case, when an overload current flows, the oscillation circuit 35 skips the command signal as a radio wave, and the radio wave receiving circuit 36 receives the command signal of the radio wave. As a result, the bypass switch 1 can be automatically opened.

As shown in FIG. 8, although this alternative is not directly related to the gist of the present invention, an amplifier 33 is provided instead of the carrier drive circuit 29 of the overload detector 22, and a speaker 34 is connected to the amplifier 33. Provide. In this case, when an overload current flows, a sound is output from the speaker 34 by the amplifier 33. Therefore, when the sound is heard, the opening switch 25 is turned off and the bypass switch 1 can be manually opened.

It should be noted that the present invention is not limited to the above-described embodiment, and can be arbitrarily changed without departing from the spirit of the present invention.

[0055]

As described above in detail, according to the present invention, when an overload current is detected when the bypass switch is closed, the bypass switch can be opened. This has the effect of preventing burning of the transformer and blowing of the primary cutout fuse.

[Brief description of the drawings]

FIG. 1 is an electric circuit diagram showing a configuration of a bypass switch, a voltage detector / phase detector, and an overload detector of the present invention.

FIG. 2 is an electric circuit diagram showing an internal configuration of a power detection / phase detector.

FIG. 3 is an electric circuit diagram showing an internal configuration of a drive circuit.

FIG. 4 is an electric circuit diagram showing an internal configuration of an overload detector.

FIG. 5 is an explanatory diagram showing a state in which a bypass switch is mounted on the low voltage side of both A and B banks.

FIG. 6 is an explanatory diagram of injecting a command signal into a grounded connection cable to open a bypass switch.

FIG. 7 is an explanatory diagram of opening a bypass switch by radio waves.

FIG. 8 is an explanatory diagram for notifying that an overload current has flowed by a buzzer.

FIG. 9 is an explanatory diagram showing a conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Bypass switch, 23 ... Drive contact as opening drive means, 21 ... Carrier receiving circuit as receiving means, 26 ... Carrier transmitting circuit as transmitting means, 27a, 27b ... Comparison circuits as discriminating means, 30a, 30b ... Signal injector as injection means, 35 ... Oscillator circuit as transmission means, 36
... A radio wave receiving circuit as receiving means, A, B ... Bank, L
A, LB, LC, LN ... connection cable, CT1, CT2
... current transformer as overload current detection means, CT3 ... current transformer as signal injection means, N1, N2 ... signal input lines as signal input means

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-2-32720 (JP, A) JP-A-3-49531 (JP, A) JP-A-4-12626 (JP, A) (58) Investigation Field (Int.Cl. ⁷ , DB name) H01H 33/59 H01H 9/54 H02J 3/04 H01H 85/00

Claims (2)

(57) [Claims] 1. A construction bypass switch with a trip device for connecting low-voltage sides of both banks by a connection cable and switching one bank to the other bank, wherein an overload current of a transformer in one of the banks is detected. Load current detecting means, determining means for determining that an overload current has flowed based on the detection signal of the overload current detecting means, and transmitting a command signal when the determining means determines that the overload current has flowed. Transmitting means, receiving means for receiving a command signal from the transmitting means, and opening drive means for opening a construction bypass switch based on the command signal received by the receiving means. Construction bypass switch with trip device. 2. An injecting means for injecting a command signal output from a transmitting means into a low voltage side of a bank, and a receiving input means provided on a low voltage side of the bank and inputting the command signal to a receiving means. The bypass switch for construction with a trip device according to claim 1, characterized in that: