JPH0546175B2 - - Google Patents

Description

[Detailed Description of the Invention] (A) [Field of Industrial Application] In recent years, information equipment, computers, robots, and other OA and FA equipment have been widely introduced into households and factories, and along with this, power system Instantaneous voltage drops and power outages can cause equipment malfunctions and defective products, so there is a strong demand for higher quality power distribution (stable voltage and frequency, low distortion, uninterrupted power, etc.) .

Even when replacing a pole-mounted transformer, the present invention switches the load on the transformer in parallel to the secondary side of the adjacent pole-mounted transformer, resulting in complete uninterrupted operation. The present invention relates to a low-voltage uninterruptible switching device that enables work.

(B) [Conventional technology] Conventionally, when replacing a pole-mounted transformer, work was done during a power outage, or the load on that transformer was temporarily cut off and switched to the secondary side of another pole-mounted transformer. There was some construction going on.

In other words, during the construction work, the power is cut off to the customers whose load is on the transformer, or the load is temporarily switched to another pole transformer. When switching back to another pole transformer, the phase and voltage do not necessarily match, which necessitates a power outage switch, each of which has the inconvenience of causing inconvenience to customers.

These power outages are becoming almost unforgivable due to the spread of information-related technologies such as value-added communication networks as mentioned above.

(C) [Problems to be Solved by the Invention] As described above, the present invention eliminates any power outages caused by work power outages or power outage switching due to work related to power distribution.

In other words, when replacing a pole transformer, the voltage and phase of the secondary load are calculated and displayed by a computer to the secondary power supply of another pole transformer, and the display is performed according to the display. To provide a low-voltage uninterruptible switching device that enables complete uninterrupted construction work without instantaneous power outages by making phase compatibility by switching connections or the like, and then switching in parallel.

(D) [Means for solving the problem] As shown in Fig. 1, the midpoint of any phase winding 2 of the load side windings of the three-phase transformer 1, which has the same voltage on both the power supply side and the load side. A three-phase transformer 1 that can generate a voltage and phase suitable for the existing lighting common load from any three-phase power supply on the load side, with 3 as the ground phase E phase, and this three-phase transformer 1. Indication of phase and voltage compatibility between the power supply side 6 connected to the power supply side terminal 4 of the transformer 1 and the load side 8 for shared lighting that is connected to the load side terminal 5 via the switch 7 and a calculation detection unit 9 that calculates and displays the open phase indication by a computer, and a closing mechanism 10 that closes the switch 7 when the power supply side 6 and load side 8 are compatible, and the compatible phase detected by the calculation detection unit This is a low-voltage uninterruptible switching device that allows parallel switching connections of loads to power supplies of different phases easily by matching the connection phases according to the display.

In addition, by inserting a breaker 11 into the power supply side 6 of the three-phase transformer 1 and opening it when connecting or changing the terminal, the power supply side terminal 4 of the three-phase transformer 1 can be connected to the terminal on the power supply side 6. Damage to the terminals due to the excitation current to the three-phase transformer 1 that occurs when connecting the three-phase transformer 1 can be prevented.

Next, each member will be explained.

As shown in Fig. 1, the three-phase transformer 1 has three-phase windings with the same number of turns for both the primary and secondary windings, and the intermediate point 3 of any phase of the secondary side, that is, the load side winding 2, is connected to the ground phase E. The power supply side terminals 4 are R, S, and T phases, respectively.
The load-side terminals 5 are for A, B, and C phases, and the ground phase and E phase, respectively, and these terminals have a structure that allows easy switching, such as a plug-in jack type, to facilitate phase matching operations.

The switch 7 is, for example, an electromagnetic switch, and has a structure in which it is operated by ON/OFF control from the switch operation section 16 of the calculation detection section 9.

As shown in FIG.
6 voltage dividers 13 that divide the potentials of the R, S, and T phases of the load side 8 and the E phase of the A, B, and C phases of the load side 8.
For example, an autotransformer, a waveform storage unit 14 that stores this divided voltage waveform, a microcomputer 15 that calculates and detects the presence or absence of an open phase and a compatible phase based on this waveform, a liquid phase display unit 12 that displays the calculation detection results, a switch operating section 16 that closes the switch 7 when the voltage and phase match;
It also includes a power supply circuit 17 that serves as a power source for these.

Next, the closing mechanism 10 consists of a switch 7, such as an electromagnetic switch, which is operated by ON/OFF control from the switch operating section 16.

(E) [Effect of the invention] Generally, the secondary side of the pole transformer of the distribution line is
As shown in the figure, a 3-phase 4-wire circuit is often used in which a common lamp operation system is used, in which the V connection is made between a and b and grounded to form the E phase.

However, in order to balance the loads on each phase of the distribution line, the high voltage side of the transformer is connected to U-V-W, V-W-
They are used in connection with U, W-U-V, changing the phase order as appropriate.

Therefore, when replacing a transformer due to an increase in the capacity of the transformer, etc., the phase order on the secondary side of each transformer is not necessarily the same.

Therefore, when carrying out work during a power outage or transferring the load of the transformer to a pole transformer adjacent to the work site, parallel switching is not possible, so the work must be performed by switching to a power outage.

In the present invention, even if the phase of the secondary side of an adjacent pole transformer is different from the phase of the transformer concerned, the load of the transformer can be applied without interruption by parallel switching to this transformer. With the low-voltage uninterruptible switching device, you can calculate and display the compatible phase, and according to the display, you can easily match the phases by switching the connection wires from the adjacent transformer connected to this device. When the display is confirmed and the switch 7 is turned on using the switch operation unit 16, the load is completely uninterrupted and can be switched in parallel to the secondary side of the adjacent pole transformer.

As a phase matching means, U-V-W, V-W are used for the high voltage side connection in the lighting common connection on the secondary side of the pole transformer shown in Figure 2.
-U, W-U-V, and the phase relationship of each phase on the secondary side of the pole transformer in each case is a-b-c shown by the solid line in Figure 3, There are three ways: a'-b'-c' shown by the thick line, and a''-b''-c'' shown by the chain line.

From this figure, the same phase and voltage as a-b-c is c'-a'-b' or b''-c''-
a″.

This principle is applied to the three-phase transformer 1 of the present invention, in which the phases a-b-c on the load side are not changed, but the phases on the power source side are a-b-c, c'-a'-b. ′、
It can handle any of the cases b″-c″-a″.

That is, in the case of FIG. 4, both the load side abc and the power supply side abc have the same phase, and of course parallel connection is possible. Next, in the case of Fig. 5, the load side a
-b-c, the power supply side c'-a'-b' has the same phase, and parallel connection is possible; ``−a'' becomes the same phase and parallel connection is possible.

In this way, even in the case of adjacent power supplies with different phases, by making the connections shown in Figures 4, 5, and 6, you can connect the loads in parallel on the load side a-b-c without interruption. It is something that can make it possible.

Next, as shown in FIG. 1, the calculation detection unit 9 divides the potentials of the power supply sides R, S, T and the load sides A, B, C with respect to the ground phase E using a voltage divider 13, for example, an autotransformer. The six divided voltage waveforms are A/D converted and simultaneously stored in the waveform storage section 14.

The microcomputer 15 calculates the instantaneous values of the stored voltage waveforms of each phase on the power supply side and the load side to obtain the instantaneous voltage value between each phase. Voltage (effective value)
and calculate the phase.

In addition, in a 3-phase 4-wire circuit, if the voltage between each phase is normal, the voltage between A-B, B-C, and A-C phases is
200V, 100V between A-E and B-E phases, and 173V between C-E phases. However, in the case of a phase failure or lack of compatibility between each phase, these abnormalities can be detected in the waveform storage unit 14.
The microcomputer 15 calculates and detects the result.

Then, from this calculation result, a connection change message for the phase that is missing and a compatible phase and the voltage between each phase are calculated and displayed on the liquid crystal display section 12.

Next, the closing mechanism 10 switches the phase order on the power supply side according to the compatibility display on the calculation detection section 9, and after confirming the compatibility display on the liquid crystal display section 12, operates the switch operation section 16. The switch 7 is turned on to connect the load in parallel to the power supply side.

If the load-side lead-in line is then disconnected from the secondary side of the replaced transformer, the load will be switched in parallel to the adjacent pole transformer without any power outages.

After replacing the pole-mounted transformer, check that the wiring of the new transformer after replacement is the same as that of the transformer before replacement, connect the load-side lead-in wires as before, and open switch 7. The load will then be switched to the new transformer without interruption. Then, remove this device.

To check whether the wiring of the new transformer after replacement is the same as that of the transformer before replacement, prepare the calculation detection part of this device separately, and connect it to the secondary side of the new transformer. You can ensure safety by inserting it between the wire and the lead-in wire and checking the phase order before connecting.

Next, the detection operation of the arithmetic detection section 9 will be explained.

The voltages on the power supply side R, S, and T and on the load side A, B, and C are divided by six voltage dividers 13, and the divided voltages are stored in the waveform storage unit 14 and stored in the microcomputer 15. By command, R, S, T, A, B, C are repeatedly read in the order of waveform storage unit 14 at high speed.
to be memorized.

For example, in the case of a frequency of 60Hz, the voltage for 6 channels is applied for 8 cycles (256 times for each channel) at a speed of 32 times/cycle (1920 times/second) each.
Load.

In this case, each piece of data is, for example, 12 bits.
(2 ¹² = 4096) using an A/D converter, −2048 to +
Store as a number 2047.

Note that the microcomputer 15 calculates the value of each voltage component stored in the waveform storage unit 14 to obtain the voltage and phase of each terminal and between each terminal.

The voltage is the effective value (Root−Mean−Square−
Value), it is calculated by calculating the "square root of the average value of the squares of the instantaneous values", and the phase is determined by FFT
(high-speed Freey transform).

Next, after determining the voltage and phase on the power supply side and the load side, the checks are performed in the following order, and the contents, phase replacement instructions, and phase open instructions are displayed on the liquid crystal display 12.

For example, (1) In the case of an open phase on the load side: If no voltage is applied to any of the A-E, B-E, and C-E phases, the LCD display 12 displays the open phase display for the relevant phase. indicate.

(2) Phase exchange on the load side 100V between A-E and B-E phases, and 100V between C-E phases
If 173V voltage is not applied, for example, 173V between A and E, 100V between B and E,
If 100V is applied between C and E, the exchange display of A←→C will be displayed.

(3) In the case of an open phase on the power supply side If no voltage is applied to any of the R-S, S-T, and TR phases, the corresponding phase will be displayed as an open phase.

(4) Phase replacement on the power supply side If the phase order on the power supply side is different from the phase order on the load side,
Indicates that the phases on the power supply side should be replaced to match the phase order and phase on the load side.

In other words, as for the connection method on the power supply side, if the connection is compatible with the load side phase, a message indicating that the connection can be made as is will be displayed on the LCD display 12, but in other cases, one of the following five connection exchanges will be displayed. , a connection replacement message will be displayed on the liquid crystal display 12, and if the power supply side connection is replaced according to the display, it will be compatible with the load side and connection will be possible.

Exchange R←→S, Exchange S←→T, Exchange R←
→T, exchange R→S→T→R, exchange R→T→S
→R When the power supply side and the load side can be connected as described above, the microcomputer 15 causes the LCD display 1
2 is displayed, and when the input switch is pressed, the switch operating section 16 is operated to close the switch 7. After confirming that the switch 7 has been turned on, the LCD display section 12 displays ""Inserted" is displayed.

Next, in the closing state, when the release switch of the closing mechanism 10 is pressed, the switch operating section 16 is operated to open the switch 7. After confirming that the switch 7 is open, the LCD display section 12 displays "Open". ” is displayed.

Note that the power supply circuit 17 has power supply side R, S, and T,
Power is supplied from the voltage divider 13 for each phase of the load side A, B, C, and E, and supplies power to the waveform storage section 14, microcomputer 15, liquid crystal display section 12, and opening/closing operation section 16.

As described above, the low-voltage uninterruptible switching device of the present invention transfers the load to the secondary side of an adjacent pole transformer in parallel without any interruption, even if the phases are different. It has an excellent function that allows switching and switching back to completely uninterrupted load supply even during work.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of the configuration of the present invention, Fig. 2 is a lighting common connection diagram of a pole transformer, Fig. 3 is a phase angle explanatory diagram in the same lighting common connection, and Figs. 4, 5, and 5. FIG. 6 is an explanatory diagram of the power supply side phase relative to the load side of the three-phase transformer according to the present invention. 1 is a three-phase transformer, 2 is the load side winding, 3 is the midpoint of the load side winding 2, 4 is the power supply side terminal, 5 is the load side terminal, 6 is the power supply side, 7 is the switch, 8 is the Load side, 9
10 is a calculation detection unit, 10 is a closing mechanism, 11 is a breaker, 12 is a liquid crystal display unit, 13 is a voltage divider, 14 is a waveform storage unit, 15 is a microcomputer, 16 is a switch operation unit, and 17 is a power supply circuit.

Claims (1)

[Scope of Claims] 1. An existing lighting shared load from any three-phase power supply, with the midpoint of any phase winding of the load-side winding of a three-phase transformer having the same voltage on both the power supply and load sides being the ground phase. A three-phase transformer that can generate a voltage and phase compatible with A calculation detection unit that uses a computer to calculate and display voltage and phase compatibility and open phase indications with the load side of the existing lighting common use connected to the load side, and when the power supply side and load side are compatible, the above switch is It consists of a closing mechanism that makes it possible to easily switch and connect loads in parallel to power supplies of different phases by matching the phases of the connections according to the compatible phase display detected by the calculation detection unit. Low voltage uninterruptible switching device.