JP3124584B2 - Low-voltage switchgear for construction with connection check 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 low-voltage switchgear for construction provided with a connection confirmation device used when a transformer or the like is replaced by an uninterruptible construction method in a distribution line.

[0002]

2. Description of the Related Art When performing works such as replacement of existing transformers, relocation of utility poles, and replacement of high-voltage and low-voltage trunk lines, there is a method of using a construction transformer as one of uninterrupted construction methods.

[0003] The construction transformer used in the above-mentioned method is a transformer, a high-voltage switch and a low-voltage switch for construction, which are integrally assembled as one set. A V-connection, three-phase, four-wire transformer is used, and a high-voltage switching device, such as a high-voltage cutout, that opens and closes for each of the three phases or each phase with a high-voltage fuse is connected to the high-voltage connection terminal of the transformer. Further, the low-voltage side connection terminal has a structure in which a low-voltage switch for construction provided with a connection confirmation device such as a voltage detection / phase detection function is connected.

[0004]

When the existing transformer is to be replaced by an uninterruptible construction method using the construction transformer having the above structure, the construction transformer is first placed in the construction section. After connecting the existing transformer to be replaced in parallel operation, the construction low-voltage switch is switched (turned on) to transfer the electrical circuit to the construction transformer, thereby removing the existing transformer and This is a work to install a new transformer, and it is a method to continue power transmission to the customer by the above-mentioned construction transformer during the construction.

In the above-mentioned construction method, when the power transmission is switched from the existing transformer to the construction transformer as described above, the construction low-voltage switch provided on the construction transformer side is turned on (switched). Prior to the switching operation, the operator had to change the connection between the load-side connection terminal of the low-voltage switch for construction and the low-voltage side connection terminal of the existing transformer each time according to the on-site track system.

[0006] However, the connection check device provided in the conventional low-voltage switch of this type is not able to fully cope with all of the different line systems because it is determined by the power detection and phase detection functions. Power failure due to accident or forgetting to connect neutral (ground) wire (power transmission stop accident)
There was a danger of inviting.

[0007]

SUMMARY OF THE INVENTION The present invention eliminates erroneous connection or forgetting to connect between the load-side connection terminal of a low-voltage switch for construction and the low-voltage side connection terminal of an existing transformer, particularly during the above-mentioned uninterruptible construction method. It is intended to prevent short circuit accidents and phase loss accidents (power transmission stop accidents) from occurring beforehand. The first invention has a high voltage side connection terminal via a high voltage switch provided with a high voltage fuse. Connecting a power supply connection terminal to a low voltage connection terminal of the transformer for a construction transformer to be connected to an electric wire, further connecting a load side connection terminal to a low voltage side connection terminal of an existing transformer; A connection in which the power detection and phase detection are performed based on signals detected from the side connection terminal and the load connection terminal, and furthermore, the power detection and the closing (opening / closing) of the connection are released on condition that the phase detection is correct. Low-pressure opening and closing for construction with confirmation device In the above-mentioned confirmation device, outside of the above-mentioned voltage detection and phase detection, furthermore, it is determined that each of the voltages between the power supply side connection terminal and each of the load side connection terminals to the ground is a normal voltage, and further, each of the load side connection terminals A low-voltage switchgear for construction, comprising a connection confirmation device for releasing the lock of the low-voltage switch by determining the presence or absence of a load side open signal of a frequency different from the commercial frequency or a direct current applied between the ground and the ground (ground). It proposes a vessel.

According to a second aspect of the present invention, a power supply side connection terminal is connected to a low voltage side connection terminal of an existing transformer adjacent to a construction section,
Further, the load-side connection terminal is connected to the low-voltage side connection terminal of the existing transformer in the construction section or the low-voltage distribution line connected to the same terminal, and the detection is performed based on signals detected from the power supply-side connection terminal and the load-side connection terminal. In a construction low-voltage switchgear provided with a connection confirmation device for performing power and phase detection, and further unlocking the closing (closed circuit) on condition that the power and phase detection are correct. The apparatus determines whether each of the power supply side connection terminals, each of the load side connection terminals, and the voltage between the ground and each of the terminals other than the power detection and the phase detection is a normal voltage, and further, determines whether each of the load side connection terminals is a ground (ground). ) A low-voltage for construction including a connection confirmation device configured to release the lock of the low-voltage switch by determining whether or not there is a load side open signal of a frequency different from the commercial frequency or a direct current applied to the low-voltage switch. It is intended to propose a 閉器.

[0009]

[Function] Only when the voltage detection and phase detection are correct, the closing lock of the low-voltage switch for construction is not released, and the voltage between the power supply side and the load side connection terminal to the ground is a normal voltage. At the same time, this is a construction low-voltage switch with a connection confirmation device that determines the presence or absence of a load-side open signal at a frequency different from the commercial frequency and releases the above-mentioned closing lock. It is possible to prevent the occurrence of a short circuit accident due to connection, or the occurrence of a phase loss accident (power transmission stop accident) due to forgetting to connect the neutral wire.

[0010]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. FIG. 1 schematically shows the structure and wiring diagram of a low-voltage switchgear 1 for construction. A switch 2 or a low-voltage switchgear 1 for construction is provided in a case 2. A detection circuit 4 is provided which determines whether the connection state is correct or not based on signals from the power supply side connection terminal and the load side connection terminal, and releases the closing lock of the low voltage switch for construction only when the connection is correct. .

Reference numerals 5, 6, 7, 8 and 9, 10, 11, 12 denote four power-supply-side connection terminals and load-side connection terminals respectively attached to the side surfaces 2a, 2b on both sides of the case 2. The terminals of the power supply side connection terminals are busbars 13, 14, 15, 16 in the case 2.
Thus, the power supply terminals 17, 18, 19, and 20 of the switching unit 3 are connected to the respective terminals of the load terminals 21, 22, 23, and 24 of the switching unit 3. They are connected by bus bars 25, 26, 27, 28, respectively.

As shown in FIG. 2, the power-supply-side connection terminals 5, 6, 7, and 8 protruding from the side surface 2a of the case 2 are formed by a tightening connection method, as shown in FIGS. It is provided via bushings 29, 30, 31, and 32. The load-side connection terminals 9, 10, 11, and 12 are of a slip-on type capable of one-touch connection.

The power-supply-side and load-side connection terminals are shown as neutral (ground) line connection terminals 5, 9, U
The phase connection terminals 6 and 10, the V phase connection terminals 7 and 11, and the W phase connection terminals 8 and 12 are arranged in this order. Reference numeral 33 denotes a ground terminal having one end connected to the bus bar 13 of the neutral wire connection terminal 5 on the power supply side and the other end penetrating the bushing 34 and protruding from the upper surface 2c of the case 2; Neutral wire connection terminal 5,
9 is grounded via the case 2 by the short-circuit plate 35 provided. When a withstand voltage or insulation resistance test is performed, the short-circuit plate 35 is used.
A high voltage is applied between the ground terminal 33 and the case 2 in a state where the switch is removed, and a test of the low-voltage switch for construction is performed.

Reference numerals 36, 37, 38, and 39 denote main contacts of the opening / closing section 3. When the output from the detection circuit 4, the plunger 41 of the lock device 40 is pulled. When 43 (FIG. 2) is removed and the operation handle 42 is released, manual operation (closing) can be performed with the handle for the first time.

Reference numeral 4 denotes a detection circuit which is a main part of the connection confirmation device. The detection circuit includes a connection terminal of a neutral (ground) line on the power supply side and U, V,
Detection of whether the voltage between the connection terminals of each W phase, that is, the ground voltage is a normal voltage, and the ground connection between the connection terminal of the neutral (ground) wire on the load side and the connection terminals of the U, V, and W phases. Detects whether the voltage is a regular voltage.

Reference numeral 44 denotes an open signal transmitter connected between the connection terminals 9, 10, 11, 12 on the load side and the ground E via a high resistance 45, as shown in FIG. The load side open signal of a 225 Hz or DC signal different from the commercial frequency of 60 Hz or a DC signal (at the input stage, the voltage is about 25 V by a divided voltage) is injected by the transmitter. 46
Denotes a power supply for driving the detection circuit 4 connected to the V phase.

FIG. 5 is a block diagram for the V phase (for one phase) in the configuration of the detection circuit 4. 5 and 6, 7 is a power supply side connection terminal, 47 and 47 'are voltage-dividing resistors for input signals, 48 is a signal input from the power supply side connection terminal, and is inputted to a next stage power detection determination circuit 49. And an input circuit for outputting to the amplifying circuit 50. The input circuit 49 determines whether the detected signal of the power supply side connection terminal 7, that is, the ground voltage is a normal voltage. Is a power detection determination circuit that turns on the LED 52 of FIG.

11 is a load side connection terminal, 44 is a load side connection terminal
A transmitter for a load side open signal connected between 11 and the ground E, 53 and 53 'are voltage dividing resistors, 54 is an input circuit, 55 is an amplifier circuit, and 56 is, for example, when the open signal is an open signal of 225 Hz. A filter circuit 57 that allows only the frequency to pass, an open signal determination circuit 57 that determines whether the open signal is “present” or “absent” based on the presence or absence of the output from the filter circuit 56 A signal of High (hereinafter, referred to as H) or Low (hereinafter, referred to as L) is output according to "None".

Reference numeral 58 denotes an inverting circuit for inverting the output from the open signal judging circuit 57. The inverting circuit 58 inputs the output from the inverting circuit 58 to the next-stage line selecting circuit 59. L or H from the inverting circuit 58 according to “absence”
Is input to the line selection circuit 59.

Reference numeral 60 denotes a power detection judging circuit for detecting whether the voltage between the connection terminal 11 on the load side and the ground E is at a regular voltage to ground, and 62 denotes an output of the power detection judging circuit 60. And an LED for power detection display, which is lit through the display circuit 61, receives the detection signals of both terminals of the power supply side connection terminal 7 and the load side connection terminal 11, compares them, and determines whether they are in phase or out of phase depending on the difference. In the case of the same phase, the output becomes LOW (hereinafter referred to as L) and the display LED 64 continues to be turned off. Output to the display circuit 65 becomes H, and the display LED 64 blinks.

Reference numeral 66 denotes a button switch for selecting a track,
The low-voltage distribution system of the construction section is three-phase four-wire system, single-phase three-wire system, single-phase two-wire system, or no-voltage (for new customers, the connection state on the high-voltage side of the transformer is three-wire connection or 2) to select one of them by switching the button switch. When the button is operated, the release condition of the closing lock of the low-voltage switchgear 1 for construction shown in Table 1 is accompanied by the line system. Automatically switch.

[0022]

[Table 1]

The release condition of the closing lock shown in Table 1 is as follows. When the uninterruptible construction method is performed, the load-side connection terminal of the low-voltage switch 1 for construction provided on the transformer for construction and the low-voltage connection of the existing transformer are used. When the connection between the terminals is correct,
It means the conditions under which the low-voltage switchgear 1 for construction can be put in.
As shown in Table 1, the conditions are set for the power supply side connection terminals 6, 7, 8 and the load side connection terminals 9, 10, 11, 12 of the low voltage switch for construction for each power distribution system.

The numerical values in the power detection items in Table 1 indicate the voltages of the power supply side and load side connection terminals as viewed from the neutral line, that is, the normal voltages of the ground voltage, and can be seen from the low voltage side connection diagram of FIG. For different capacity V connection three-phase four-wire construction transformer
The normal voltage value of the ground voltage between the connection terminals 6, 7, 8 of the U, V, W phases on the power supply side of the low voltage switchgear 1 for construction connected to the low voltage side connection terminals 150, 152, 153 in 70 and the ground E For example, “0” means that the voltage is in the range of 0V to 20V, and “100” means that the voltage is in the range of 85V to 1V.
In the range of 15V, and "173" is 147V ~
It means that it is in the range of 199V. These numerical values are determined in consideration of variations such as voltage fluctuations due to a change in the load condition and an increase in ground (neutral) line potential due to leakage current flowing to the ground.

Next, regarding the items of the load-side oven signal in Table 1, the power supply or transmission is performed between the neutral line on the load side of the low-voltage switchgear 1 for work, the connection terminals of the U, V, and W phases and the ground. Different from the 60Hz commercial frequency applied by the
"None" in this item means whether a 25 Hz signal is output to each of the above connection terminals. For example, as shown in the three-phase four-wire low-voltage distribution system in FIG. Terminals 9, 10, 11, 12 for each phase on the load side of the unit 1
Indicates that the connection between the low-voltage side connection terminals 81, 82, 83, and 84 of the existing transformer 80 on the replacement side connected to these connection terminals is normal. This means that the ground (ground) return path of the open signal is not formed due to forgetting or poor contact, so that the signal appears at the corresponding terminal.

Further, in the phase detection items in Table 1, "O" indicates that phase detection is required, and "-" indicates that phase detection is not required. Next, the load-side open signal shown in Table 1 will be described in more detail.

In the single-phase three-wire distribution system shown in FIG. 9, a low-voltage service line is supplied to a low-voltage customer 99 via an existing transformer 90.
When power transmission is performed via 140, 141, and 142, when the existing transformer 90 is replaced (replaced), the construction transformer 70 is connected to the existing transformer 90 with a high-voltage cable.
After connecting 118, 117 and low-voltage cables 98, 97, 96 for parallel operation, load-side connection terminals of the low-voltage switch for construction prior to turning on the low-voltage switch 1 for construction on the transformer side for construction 9, 10, 11 and low-voltage side connection terminal 9 of existing transformer 90
When checking the connection status of the low-voltage cables 98, 97, and 96 between 1, 92, and 93, the neutral wire (ground) on the low-voltage switch side (connected to the neutral wire phase of the transformer for construction) Even if the connection of the low-voltage cable 98 connecting the connection terminal 9 of the existing transformer and the connection terminal 92 of the neutral (ground) line phase of the existing transformer is disconnected, the operator can usually use the conventional method to detect the voltage. And the two connection terminals 9 and 92 are at the same ground potential, so that there is a risk that the two terminals 9 and 92 may be erroneously determined as if they were connected by the cable 98. .

Therefore, if the construction low-voltage switch 1 is turned on in this state, the existing transformer 90 is disconnected, and the operation of the construction transformer 70 is shifted to the stand-alone operation, the neutral condition as described above is obtained. Due to the disconnection between the lines, the 200 V is transmitted only to the low-voltage consumer 99, and an open phase (power transmission stop) state in which the 100 V is not transmitted is naturally caused.
Therefore, in the present invention, as a countermeasure, as shown in FIG. 1 and FIG.
A transmitter 44 is connected between 0, 11, 12 and the ground E via a high resistance 45, for example, as shown in FIG.
44-High resistance 45-Neutral connection terminal 9 for low voltage switch 9-Low voltage cable 98-Neutral wire (ground) connection terminal 92 for existing transformer
-The above-mentioned open signal is injected at the same time when the feedback circuit for the ground (ground) E is formed.

Thus, for example, if the cable 98 for connecting the connection terminals of the neutral wire (ground) is disconnected, the ground (ground) feedback circuit is not formed, and as a result, the load side A voltage based on an open signal is output to the connection terminal 9 so that it is possible to determine that the connection is defective. If the connection of the cable 98 is normal, a ground feedback circuit (short circuit) is formed. The connection terminal 9 is configured not to output a voltage based on the open signal, and it is possible to determine whether the connection of the cable is correct or not based on the presence / absence of the open signal.

In the above description, the open signal is different from the commercial frequency of 60 Hz, for example, the noise is relatively small.
Although 225 Hz was used, any frequency other than the above may be used as long as it is easy to determine the commercial frequency, and a DC signal may be used.

Returning to the block diagram of FIG. 5, and continuing the description of the detection circuit 4, a line selection circuit 59 is shown in Table 1 if, for example, the power distribution system is selected to be a three-phase four-wire system. In the case of a single-phase two-wire system, there are twelve items, and in the case of no-voltage, high-voltage side connection with three-wire connection, there are eleven items.

Therefore, the output from the detection circuit 4 is output to the lock release circuit 100 in the subsequent stage only after the connection is confirmed, when all of the items, that is, the AND condition are satisfied.
103 inverts the L signal of the line selection circuit 59 to H by the inversion circuit 101 when the AND condition for connection confirmation is not satisfied,
Further, there is an alarm buzzer which sounds by a signal passed through the buzzer circuit 102, and the alarm buzzer 103 keeps sounding until the connection is corrected to a normal state. 104 is LE for line selection display
D, and when the button-shaped switch 66 is switched, the LED 104 corresponding to the selected power distribution system interlocks with this operation.
Only lights up.

Reference numeral 100 denotes an unlocking circuit as described above. When the closing unlocking condition shown in Table 1 is satisfied, an output is made from the line selecting circuit 59, and a confirmation button is further provided.
When the 105 is operated, the closing lock plunger 41 is released by the output of the lock release circuit 100, and when the lock pin 43 attached to the handle is removed, the operation handle 42 of the low-voltage switchgear 1 for manual operation is closed (closed). Operation becomes possible.

In the lock release circuit 100, the output of the line selection circuit 59 and the output of the latch circuit latched by the output of the confirmation button 105 are input to the AND circuit, and there is an output signal from the line circuit 59. When the confirmation button 105 is operated, the latch circuit is latched, the confirmation display LED 106 indicating that the circuit is ready to be turned on is lit, and at the same time, the plunger 41 is disengaged from the operation handle 42 as described above, and the low-voltage switch for construction is used. 1 is in a state in which it can be turned on. 107 is an auxiliary contact interlocking with the opening / closing section 3 of the low-voltage switch for construction. When the opening / closing section 3 is operated and closed, the auxiliary contact 107 is closed to release (cancel) the latch circuit and release the suction of the plunger 41. I do. Reference numeral 108 denotes a trip display LED that indicates by an output from the display circuit 109 that an overcurrent or a short circuit accident has occurred on the load side of the low-voltage switch 1 and the construction low-voltage switch has been urgently opened. Show. Reference numeral 170 denotes a test button, which indicates a trip display LED that is displayed when the button 170 is pressed. Also
Reference numeral 170 denotes a test button. When the button 170 is pressed, two test signals having different phases are output from the signal transformer incorporated in the test circuit to the input circuits on the power supply side and the load side, respectively. Then, a circuit check and a lighting check of various display LEDs are performed. The coils of the signal transformer are wound in reverse order, and two signals with different phases are connected to the input circuit on the power supply side.
48 and the other is input to the input circuit 54 on the load side.

Next, a description will be given of an uninterruptible power supply method for replacing (exchanging) an existing transformer when the line system (low-voltage distribution system) shown in FIG. 7 is a three-phase four-wire system. The operation of the construction low-voltage switch 1 will be described with reference to FIGS.

First, the construction transformer 70 integrally incorporating the construction low-voltage switch 1 was transported to the site of the construction section (stop section), and the existing transformer 90 scheduled to be replaced (replaced) was attached. A construction transformer 70 is mounted below the utility pole. In this case, the construction transformer 70 may be left on the construction vehicle that stops below the utility pole.

The mounted or installed construction transformer 70 is connected to a high-voltage switchgear for connecting the high-voltage terminal to the terminal, for example, a high-voltage cable 116, 117, 118 via a high-voltage cutout 113, 114, 115. Electric wire R,
Connecting wires to S and T and to the low voltage side terminal of construction transformer 70 15
0, 151, 152, 153, the power supply side connection terminal 5,
The connection terminals 9, 10, 11, and 12 of the low-voltage switchgear 1 for connecting 6, 7, and 8 are connected to the low-voltage terminals 81, 82, and 83 of the existing transformer 80 by the low-voltage cables 98, 97, 96, and 95. , 84 or the low-voltage service lines 119, 120, 121, 122 so that they are temporarily connected in parallel operation.

In the above, the high pressure cutout 11
3, 114, 115 and the low-voltage switchgear 1 for construction are connected with their electric lines open. When the temporary connection is completed and the high-voltage cutouts 113 to 115 are turned on, the power supply circuit 46 of the detection circuit 4 of the low-voltage switchgear 1 for construction connected between the V-phase and the neutral line is turned on. In this ON state, the test button 170 is first pressed to check the lighting of the LED and check the circuit.

The power supply side connection terminal 5 of the low voltage switch 1
A predetermined ground voltage is input to 6, 7, 8 and the load-side connection terminals 9, 10, 11, and 12, is further divided by the input stage voltage-dividing resistors, and is then input to the input circuits 48 and 54, respectively. You.

An input signal from one power supply side connection terminal 7 is input to a power detection judging circuit 49, and when the signal level is equal to or higher than a predetermined value (threshold), the output H of the power detection judging circuit 49 becomes high. It is input to the next display circuit 51, and the LED 52 for power detection lights up, indicating that a voltage of a predetermined value is applied to the power supply side connection terminal.

The output signal from the input circuit 48 is also input to the amplifying circuit 50 and further to the next-stage differential phase detection circuit 63. On the other hand, a signal input to the load-side connection terminal 11 of the low-voltage switchgear 1 for construction is also input to the input circuit 54, and the signal detection determination circuit 60 determines whether the signal level is equal to or higher than a predetermined value. After passing through the LED 61, the LED 62 for power detection is turned on. After the signal output from the input circuit 54 is input to the amplifier circuit 55, the signal is input to the differential phase detection circuit 63 and the filter circuit 56 described above.

The signal of the load terminal input to the phase detection circuit 63 is waveform-shaped, and the phase of the waveform-shaped signal input from the power supply terminal is compared with the phase thereof. For example, if the phase is within ± 10 °, it is determined that the output is L, and if the phase is different, the output is H.

Therefore, in the case of the same phase, the output from the phase detection circuit 63 is L, and the display circuit 65 at the next stage does not turn on the phase detection circuit LED 64 to indicate that the phase is the same. Also, the output signal of the phase detection circuit 63 is inverted by the next inversion circuit 124 and
Entered in 59.

As described above, the load-side connection terminals 9 and
A transmitter 44 that outputs an open signal having a frequency of 225 Hz different from the commercial frequency is connected between these terminals and the installation E via high resistances 45 between these terminals and the installation E. The signal is input to a filter circuit 56 via an amplifier circuit 55.

As described above, this open signal is generated when the load-side connection terminals 9, 10, 11, 12 of the low-voltage switchgear 1 for construction are in a non-connection state, or a similar contact failure or disconnection of the cable. When there is, since there is no or very small voltage drop of the open signal due to the high resistance 45, an output by the open signal is generated at these load-side connection terminals 9, 10, 11, and 12, and this is input to the input circuit 54.

As described above, if the signal input to the filter circuit 56 is an open signal, the signal passes through the filter circuit 56, is input to the open signal determination circuit 57, and the output of the open signal determination circuit 57 becomes H. This is input to the line selection circuit 59 via the inversion circuit 58. In this way, it is detected that the load side connection terminals 9, 10, 11, 12 and the low voltage connection terminals 81, 82, 83, 84 of the existing transformer connected to the same terminals are in an open state where they are not connected.

When the load-side connection terminals 9, 10, 11, 12 are in a completely correct connection state via the low-voltage cables 98, 97, 96, 95, these load-side connection terminals are connected to the low-voltage side of the existing transformer. Since a ground (ground) feedback circuit is formed between the connection terminals 81, 82, 83, and 84, and the voltage drop of the open signal due to the high resistance 45 increases, the load-side connection terminals 9, 10, 11, and 12 are connected. Does not produce an output due to the open signal (below a predetermined value), and therefore, there is no output from the filter circuit 56. Therefore, the output of the open signal determination circuit 57 becomes L, and it is detected that the connection terminal and the low voltage side terminal of the existing transformer are completely open by the low voltage cable.

The signal L or H inverting circuit 58 which has determined the connection between the load side connection terminal and the low voltage connection terminal of the existing transformer as described above is input to the next line selection determination circuit 59. For the line selection circuit 59, in addition to the signals input through the open signal determination 57 and the inversion circuit 58, each signal from the power detection determination circuit 49 on the power supply side connection terminal side, and the power detection on the load side connection terminal side A signal from the determination circuit 60, a signal from the phase detection circuit 63, and a signal from the inversion circuit 124 are input.

Note that a line selection switch 66 is connected to the line selection circuit 59, and the LED 104 indicated as three-phase four-type is turned on at the same time when the power is turned on. Then, the switch 66 is switched to select a low voltage side terminal 81, 82, 83, 84 of the existing transformer, that is, a power distribution system that matches the line system (low voltage distribution system) to be constructed. As a result, L of the selected distribution system is
ED lights up.

That is, the switching operation of the line selection switch 66 is performed by changing one of the AND circuits provided for each of the five line systems set in the line selection circuit 59.
The D condition is selected, and the AND condition is a condition for releasing the closing lock of the low-voltage switch, and is set in advance for each power distribution system as shown in Table 1 above.

As described above, when the signal input to the line selection circuit 59 satisfies the conditions of Table 1 set for each power distribution system, a signal is output from the line selection circuit 59 and the unlock circuit 100
Is input to The lock release circuit 100 forms an AND with an output from the line selection circuit 59 and a signal from the confirmation switch 105, and a signal is output from the lock release circuit 100 by both signals. If the condition of Table 1 is not satisfied in the line selection circuit 59, the buzzer circuit 102
103 sounds to alert the operator that the connection is abnormal.

If the connection is changed and the condition is satisfied so that the condition is satisfied, the buzzer 103 stops sounding and, at the same time, outputs a signal for unlocking to the unlocking circuit 100 of the next stage. Become. When the signal is output from the lock release circuit 100 as described above, the plunger 41 that locks the closing of the construction low-voltage switch 1 is sucked by the solenoid 125 and the closing of the operation handle 42 is released, and the construction low-pressure switch is released. 1 can be manually turned on. The switchable LED 106 is also illuminated at the same time, and indicates that the low-voltage switch 1 can be closed.
FIG. 10 shows the display state of the LEDs and the like in this state.

Therefore, when the operating handle 42 of the low-voltage switch 1 for construction is operated and the switch 3 of the switch is turned on, the construction transformer 70 and the existing transformer 80 are operated in parallel, and both transformers are temporarily operated. Low voltage consumers (low voltage distribution lines)
Transmission continues for 99.

When the low-voltage switchgear 1 for construction is turned on in this way, the auxiliary contact 107 interlocking with the switching unit 3 is closed as described above, whereby the LED 106 that can be turned on is canceled from the lit state and turned off. The buzzer that sounds after the closing, and the closing lock release condition shown in Table 1 is different.
In 03, the sound is canceled and the stopped state is continued, and the lighting of the LED on the load side for power detection which is going to be newly turned on from the turned off state after being turned on is also canceled and the turned off state is continued. The plunger 41 is canceled from the suction state and returns to the non-suction state.

However, the plunger 41 is returned and is in the protruding state, but the mechanism of the plunger 41 is free to open, and the operating handle 42 of the low-pressure switch 1 can be operated at any time from this closed state, and the low-pressure switch 1 The opening / closing section 3 can be opened.

Next, the high voltage pull-down line 1 connected to the high voltage side connection terminals 133, 134, 135 and the low voltage side connection terminals 81, 82, 83, 84 of the existing transformer 80 to be replaced in the parallel operation state.
Remove the not-shown wrap around the connecting lines 30, 131, 132 and the low pressure drop lines 119, 120, 121, 122. In other words, after opening the high-voltage cutouts 160, 161, 162 connected to the high-voltage side connection terminals, the high-voltage underline 13 connected to the high-voltage cutout 13
0, 131, 132 are disconnected from the high voltage distribution lines R, S, T,
Also, connect the low-voltage connection terminals 81, 82, 83, 84 of the existing transformer to the low-voltage distribution line (low-voltage connection terminal of the construction transformer) with the low-voltage drop-in wires 119, 120, 121, 122 or the low-voltage of the construction transformer. After disconnecting from the cables 97, 98, 96, and 95, the existing transformer 80 is dropped on the ground and replaced with a new one.

Further, the new transformer for replacement is attached to the telephone pole again in the same manner as the existing transformer removed, and the connection terminals on the high voltage side and the low voltage side are connected in parallel to the construction transformer 70 during the temporary power transmission. Connected to drive. The connection between the low-voltage side connection terminal of this new transformer and the load-side connection terminal of the low-voltage switchgear for construction is checked while connecting each phase using the conventional voltage detector / phase detector. And start parallel operation.

When the new transformer is in parallel operation with the construction transformer in this way, the construction low-voltage switch 1 of the construction transformer 70 is opened, and then the high-voltage cutout 11 is opened.
3, 114 and 115 are opened, the high and low voltage cables of the high and low voltage connection terminals are disconnected, and the construction transformer 70 is removed and dropped on the ground to complete the construction.

In the above, when replacing the existing transformer, a high-voltage switch (high-voltage cutout) is integrated into the high-voltage terminal and a low-voltage switch for construction is integrated into the low-voltage connection terminal. The construction method using a construction transformer was explained. In addition, only the construction low-voltage switch (1) connected to the low-voltage side connection terminal of the construction transformer was used alone, and this was placed next to the construction section. Low-voltage customers who connect to the low-voltage side connection terminal of the existing transformer to be installed in parallel operation and then turn on the low-voltage switch for construction, thereby connecting to the existing transformer to be replaced in the construction section However, even when using the uninterruptible construction method (construction method using low-voltage interconnection using low-voltage switches), power transmission from the adjacent transformer is continued via the low-voltage switch for construction during the replacement. Power supply side of switch for Connection forget or loose connections for load side connection terminal can be prevented in the same manner as described above by the connection confirmation device.

[0060]

As described above, in the present invention, prior to the closing operation of the low-voltage switch for construction, the condition for releasing the closing lock is determined by setting the neutral point of the power supply connection terminal and the load side terminal of the low-voltage switch for construction. (Ground) In addition to the phase detection signal that is in-phase or out-of-phase with the voltage detection signal depending on the magnitude of the voltage between the line phase and each phase connection terminal, the commercial frequency is also applied between the load-side connection terminal of the low-voltage switchgear for construction and ground. Since the load side open signal with a different frequency from that of the load side is added, if the connection between the ground phase connection terminal of the load side connection terminal and the ground phase connection terminal of the existing transformer is forgotten, contact failure or disconnection occurs, the above lock will be applied. Since the release condition is not satisfied, and the low-voltage switch for construction cannot be turned on, a phase-out accident (for example, a power transmission stop accident due to forgetting the connection of the neutral wire, etc. due to the post-connection when the low-voltage switch was turned on, as was conventionally caused) ) And short circuit accidents , Workability, it is extremely beneficial in safety.

[Brief description of the drawings]

FIG. 1 is a schematic connection diagram of an embodiment of the present invention.

FIG. 2 is a front view of the embodiment of the present invention.

FIG. 3 is a bottom view of the embodiment of the present invention.

FIG. 4 is a connection diagram of a main part of the embodiment of the present invention.

FIG. 5 is a block diagram of a detection circuit showing one phase (V phase) according to the embodiment of the present invention.

6 is a further simplified block diagram of the detection circuit of FIG. 5;

FIG. 7 is an explanatory diagram showing a connection state at the time of an uninterruptible construction method when the line system is a three-phase four-wire system.

FIG. 8 is a low-voltage side connection diagram of a construction transformer.

FIG. 9 is an explanatory diagram showing a connection state at the time of uninterruptible construction when the line system is a single-phase three-wire system.

FIG. 10 is a front view of a low-voltage switch showing a display state of an LED or the like when a cable connection is correct in the three-phase four-wire system of FIG. 7;

[Explanation of symbols]

 1 Low-voltage switch for construction 3 Switch 5,6,7,8 Power connection terminal 9,10,11,12,13 Load connection terminal 41 Plunger 42 Operation handle 44 Transmitter 70 Construction transformer 80 Existing transformer 95,96,97,98 Low-voltage cable 99 Low-voltage customer 113,114,115 High-voltage cable E Ground R, S, T High-voltage distribution line

──────────────────────────────────────────────────続 き Continuing on the front page (72) Norifumi Hotta, Inventor 35, Fukamama, Nagagusa-cho, Obu, Aichi Prefecture Japan High Voltage Electric Co., Ltd. Japan High Voltage Electric Co., Ltd. Technical Research Institute (56) References JP-A-5-234473 (JP, A) JP-A-63-32818 (JP, A) JP-A-49-6422 (JP, A) -26210 (JP, U) Japanese Utility Model Showa 62-98427 (JP, U) JP-B-44-144 (JP, B1) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01H 31/04 H01H 33/59 H02G 1/02

Claims (2)

(57) [Claims] 1. A power supply connection terminal is connected to a low-voltage side connection terminal of a construction transformer connected to a high-voltage distribution line via a high-voltage switch having a high-voltage fuse. Side connection terminal is connected to the low voltage side connection terminal of the existing transformer, and the power detection and phase detection are performed by signals detected from the power supply side connection terminal and the load side connection terminal. The connection (closed circuit) is unlocked on condition that the power supply is correct, and the low-voltage switchgear for construction is provided with a connection confirmation device. Determination that each of the voltages to ground of the side connection terminal and each load side connection terminal is a normal voltage, and furthermore, a frequency or DC load different from the commercial frequency applied between each load side connection terminal and ground (ground). Side open A low-voltage switch for construction, comprising a connection confirmation device configured to release a lock of the low-voltage switch by determining whether a signal is present. 2. A power supply side connection terminal is connected to a low voltage side connection terminal of an existing transformer adjacent to a construction section, and a load side connection terminal is connected to a low voltage side connection terminal of an existing transformer in the construction section. Alternatively, the terminal is connected to the low-voltage distribution line connected to the terminal, and the power detection and phase detection are performed based on signals detected from the power supply side connection terminal and the load side connection terminal. In a low-voltage switch for construction provided with a connection confirmation device that is configured to release the lock of closing (closing) on condition that the above-mentioned confirmation device is connected to each power supply side in addition to the voltage detection and phase detection. Judgment that each voltage between the terminal and each load side connection terminal to the ground is a normal voltage, and furthermore, each load side connection terminal and the ground (ground)
A low-voltage switch for construction, comprising a connection confirmation device configured to release the lock-on of the low-voltage switch by determining the presence or absence of a load side open signal of a frequency different from the commercial frequency or a DC load applied therebetween.