JPH0245419B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an automatic power supply switching device for a multi-line power receiving system power system.

[Technical background of the invention]

FIG. 1 shows an example of a two-line power receiving system power system to which a conventional automatic power switching device is applied.

The power receiving power source consists of two systems, a first power receiving power source P1 and a second power receiving power source P2, and is connected to the first power receiving bus B1 and
It is connected to the second power receiving bus B2. This first
A power receiving bus connection switch 3 communicates between the second power receiving bus lines B1 and B2. Further, first and second electric motors 6 and 7 are connected to the first power receiving bus B1 and the second power receiving bus B2 via first and second load switches 4 and 5, respectively. Further, first and second transformers 8, 9 are connected to the first and second load switches 4, 5 via first and second transformer primary switches 10, 11. There is. A first distribution bus B11 and a second distribution bus B11 are connected to the secondary sides of the first and second transformers 8 and 9 via first and second transformer secondary switches 12 and 13, respectively. B21 is connected. First distribution bus B11
and the second power distribution bus B21 are connected by a power distribution bus connection switch 14. 1st and 2nd above
Third and fourth electric motors 17 and 18 are connected to distribution buses B11 and B12 via third and fourth load switches 15 and 16, respectively.

The first power receiving bus B1 and the second power receiving bus B2 are provided with first and second instrument transformers 19 and 20, respectively.
via the first and second undervoltage relays 21, 2
2 are connected. In addition, the first power distribution bus B1
Third and fourth undervoltage relays 25 and 26 are connected to the first and second distribution buses B21 via third and fourth instrument transformers 23 and 24, respectively.

In a normal system operation state, the first and second power receiving switches 1 and 2 are open, and the power receiving busbar communication switch 3 is open. Therefore, the first and second electric motors 6,
7 is a first power receiving bus B1 and a second power receiving bus B2
Powered by third and fourth electric motors 17,
18 is supplied with power via the first and second transformers 8, 9, the first distribution bus B11, and the second distribution bus B21. In addition, distribution busbar connection switch 1
4 is an open circuit.

Under normal system operation conditions as described above,
For example, if an accident occurs in the first power receiving system F1 indicated by the broken line, first the first power receiving switch 1 is opened, and then the receiving busbar connection switch 3 is switched to close. Also, the first point indicated by a dashed line
If an accident occurs in distribution system F11,
Switching is performed in which the transformer primary switch 10 and the first transformer secondary switch 12 are opened, and the distribution busbar connection switch 14 is closed. Also, in the case of an accident in the second power distribution system, the power source is switched in a similar manner.

[Problems with background technology]

In the power system described above, when power is switched, the voltage of the bus separated from the fault system at the time of power switching does not instantly become zero, and the residual voltage of motor groups 6, 7, 17, and 18 increases. Occur. At this time, when the receiving busbar contact switch 3 or the distribution busbar contact switch 14 is closed, due to the voltage difference, phase difference, and frequency difference between the residual voltage and the power supply on the healthy system side,
Inrush current flows into the grid. Therefore, the transient torque caused by the rush current is applied to the electric motors 6, 7, 17,
18, which caused damage to motor groups 6, 7, 17, and 18, as well as machines and couplings directly connected to these motor groups 6, 7, 17, and 18. In particular, when the phase difference is around 180°, a transient torque that is 10 times or more of the rated torque may occur.

In order to reduce the above-mentioned transient torque, methods (a) to (c) described below have been conventionally implemented.

(b) After the switch of the power receiving or distribution system where the accident occurred is opened, and before the phase difference between the bus bar separated from the system where the accident occurred and the healthy system becomes large,
Instant power reception or distribution bus connection switch 3, 1
4 is closed.

(b) Detect the phase between the residual voltage of the bus separated from the power receiving or distribution system where the accident occurred and the power supply of the healthy system, and synchronize the power receiving or distribution bus connection switches 3 and 14.

(c) After the switch of the power receiving or distribution system where the accident occurred is opened, the power receiving or distribution bus connecting switch 3, 14 shall be closed after the residual voltage of the bus separated from the system where the fault has occurred has sufficiently attenuated. do.

However, in method (a) mentioned above,
Immediate closing is difficult due to factors such as the time required to close the switch and the operating time of the fault detection relay. Therefore, after opening the switch of the faulty system, it takes 0.3 to 0.5 seconds to close the power receiving or distribution bus connecting switches 3, 14, and this time required causes the problem that the phase difference becomes too large. There is.

In method (b), there is a frequency difference between the residual voltage of the bus separated from the faulty system and the power supply of the healthy system, so the phase changes rapidly. Therefore, even if the synchronized phase is detected, there is a time delay in closing the switch, so there is a problem that the phase difference has already become large by the time the power receiving or distribution bus connecting switches 3 and 14 are closed. .

Method (c) is the most commonly used power supply switching method, but it takes a long time for the residual voltage on the bus separated from the faulty system to sufficiently attenuate. Therefore, the stop time of the electric motor groups 6, 7, 17, and 18 becomes longer, which causes problems as electric motor equipment. Particularly in large electric motor equipment, it takes more than 10 seconds for the residual voltage to sufficiently decay, which is a problem.

Furthermore, the method (c) described above has the following problem. In other words, in the system shown in Figure 1,
If an accident occurs in the first power receiving system F1, after the first power receiving switch 1 is opened, the voltage attenuation of the first power receiving bus B1 is confirmed by the first undervoltage relay 21, and the power receiving bus is connected. A closing command is output to the switch 3. However, at this time, if the control power supply of the power receiving bus contact switch 3 is disconnected or the closing coil is disconnected, the power receiving bus contact switch 3
is not closed. Therefore, power is not supplied to the first power receiving bus B1 and the first power distribution bus B11. In this case, even if power is not supplied to the first power receiving bus B1, it is desirable to supply power to the first power distribution bus B11 as soon as possible. However, in the conventional automatic power switching device, an operator becomes aware of an abnormality and manually opens the first transformer secondary switch 12.
It takes a considerable amount of time to close the distribution bus connection switch 14 and to supply power to the first distribution bus B11. Therefore, there is a problem that the motor 17 connected to the first power distribution bus B11 is stopped for a long time.

[Purpose of the invention]

The present invention has been made in order to eliminate the above-mentioned problems, and provides an automatic power supply switching device that can perform power supply switching at high speed in a multi-line power receiving type power system and can reduce inrush current that occurs when switching power supplies. The purpose is to

[Summary of the invention]

The automatic power switching device according to the present invention is applied to a multi-line power receiving type power system, and connects a series circuit consisting of an impedance element and a normally open bus-bar contact auxiliary switch to a power-receiving bus-bar contact main switch of the power system. A receiving system fault detection relay is provided for each receiving power source, which is connected in parallel to the power receiving switch and the distribution busbar connecting main switch, respectively, and detects a fault on the receiving power source side of the power system and opens the corresponding power receiving switch. Each power receiving bus is provided with a distribution system fault detection relay that detects a fault on the power receiving bus and opens the corresponding power receiving switch and the switch of the power distribution system connected to this power receiving bus, and the power receiving bus connecting main switch is installed on each power receiving bus. and an abnormality detection circuit that detects an abnormality in the busbar contact auxiliary switch, and a power receiving busbar contact auxiliary switch energized by the operation signal of the power receiving fault detection relay;
A power receiving system power switching circuit that sequentially turns on the power receiving bus connecting main switches, an operation signal of the power receiving system fault detection relay when the abnormality detection circuit is operated, an operating signal of the power receiving bus fault detection relay, and a power distribution fault detection relay. at least one of the operating signals of
The above object is achieved by having a configuration including a distribution system power switching circuit which is operated by two inputs and sequentially turns on the distribution busbar connection auxiliary switch and the distribution busbar connection main switch.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. 2 and 3 are a power system diagram and a block diagram of the automatic power switching device main body according to the present invention.

In FIG. 2, parts that are the same as those in FIG. 1 are given the same reference numerals, and their explanation will be omitted, and only the different parts will be explained.

The difference between FIG. 2 and FIG. 1 is that a power receiving system reactor 27 and a power receiving bus contact auxiliary switch 28 are used as impedance elements for the power receiving bus connection switch 3.
A series circuit consisting of is connected in parallel. Similarly, a series circuit including a distribution system reactor 29 and a distribution bus connection auxiliary switch 30 is connected to the distribution bus connection switch 14.

In FIG. 3, R-F1 is a contact point of a protective relay that detects an accident in the first power receiving system F1 indicated by a broken line in FIG. R-FB1 is a contact point of a protective relay that detects an accident in the first power receiving bus system FB1 shown by a dashed line in FIG.

R-F11 is a contact point of a protective relay that detects an accident in the first power distribution system F11 indicated by a two-dot chain line in FIG. Contacts R-F of these protective relays
1, R-FB1 and R-F11 are connected to the automatic power switching device main body 31.

The automatic power switching device main body 31 is composed of an automatic power switching circuit 32 for the receiving system, an abnormality detection circuit 33 that detects abnormalities in the switching circuit 32 for the receiving system, and an automatic switching circuit 34 for the automatic power switching system for the power distribution system. .

The abnormality detection circuit 33 detects abnormalities in the first and second power reception switches 1 and 2, the power reception bus connection switch 3, the power reception bus connection auxiliary switch 28, and the power reception system power automatic switching circuit 32. There is. This abnormality detection circuit 33 is connected to the first and second power receiving switches 1 and 2 of the power receiving system and the power receiving system power automatic switching circuit 32.
A contact point 33a1 that closes when the is normal.

Further, the output command of the power receiving system power supply switching circuit 32 is sent to the power receiving bus line communication switch 3 and the power receiving bus line communication auxiliary switch 28. Furthermore, the output command of the distribution system power switching circuit 34 is transmitted to the distribution bus connection switch 14.
and is sent to the distribution busbar contact auxiliary switch 30.

Next, the operation of this embodiment will be explained with reference to FIGS. 2 to 4. Figure 4 shows the first power receiving system F.
1 is a flowchart showing the operation procedure when an accident occurs in step 1.

First, a case where an accident occurs in the first power receiving system F1 will be described with reference to FIG. 4. In FIG. 3, when the power receiving system power automatic switching circuit 33 is operating normally, the contact R-F1 of the protective relay for fault detection of the first power receiving system F1 is closed, and the first power receiving system F1 is closed.
When the power receiving switch 1 is opened, the first
A fault signal of the power receiving system F1 is input. The power receiving system power supply automatic switching circuit 33 first outputs a closing command to the power receiving bus bar contact auxiliary switch 28 . And the first circuit that closes the power receiving busbar connection auxiliary switch
The power receiving bus B1 and the second power receiving bus B2 are coupled through a power receiving system reactor 27, and the inrush current is reduced. Then, after a certain period of time, the power reception bus connection switch 3 is closed, and the power reception bus connection auxiliary switch 28 is further opened, thereby switching the power supply of the power reception system.

In the above case, if the power receiving system power switching circuit 33 is abnormal, the contact R-F1 of the accident detection protective relay of the first power receiving system F1 is opened, and the contact 32a1 is closed. This causes the primary and secondary of the first transformer to
The next switches 10 and 12 are opened, and the distribution system automatic power switching circuit 34 is connected to the first power receiving system F1.
An accident signal is input.

In the distribution system power automatic switching circuit 34, the distribution busbar contact auxiliary switch 30 is first closed, and the first and second
The distribution bus lines B11 and B21 are connected by a distribution system reactor 29. After a certain period of time, the distribution bus connection switch 14 is closed and the distribution bus connection auxiliary switch 30 is opened to automatically switch the power supply of the distribution system.

Next, referring to Figures 2, 3, and 5,
The case where an accident occurs in the power receiving bus system FB1 will be explained. Figure 5 shows the first receiving bus system FB
1 is a flowchart showing the operation procedure when an accident occurs in step 1. When an accident occurs in the first power receiving bus system FB1, the contact R-FB1 of the protective relay for fault detection of the first power receiving bus system FB1 is closed, and the first power receiving switch 1, the first transformer Primary switch 1
0, the first transformer secondary switch 12 and the first load switch 4 are opened. The fault signal of the first power receiving bus system FB1 is input to the distribution system power automatic switching circuit 34.

When an accident occurs in the first distribution system F11, the contact R-F11 of the protective relay for accident detection in the first distribution system F11 is closed, and the first transformer primary switch 10 and the first The transformer secondary switch 12 is opened. The fault signal of the first power distribution system F11 is input to the power distribution system automatic switching circuit 34.

When the fault signal is input, the distribution system power automatic switching circuit 34 first closes the distribution bus contact auxiliary switch 30 and switches the first and second distribution bus B11,
B12 is coupled through a power distribution system reactor 29. After a certain period of time, the distribution bus connection switch 14 is closed, and then the distribution bus connection auxiliary switch 30 is closed.
Automatically switches the power supply of the power distribution system by opening the circuit.

In the above, we have described the case where an accident occurs in the first power receiving system F and the first power distribution system F11, but the second power receiving system F as shown in FIG.
Similar effects can be obtained when an accident occurs in the power distribution system F22 and the second power distribution system F22.

In this embodiment described above, the automatic power switching device main body 31 detects an accident in the power receiving or power distribution system and diverts the inrush current caused by the closing of each switch to the reactor, so that the load connected to the system is not affected. Inrush current is not applied. This makes it possible to reduce the generation of transient torque when the load is an electric motor.

Further, in the above embodiment, a power system with a two-line power receiving system was described, but similar effects can be obtained for multiple lines with two or more lines by configuring the automatic power switching device main body 31 corresponding to each switch. It will be done.

Further, the present invention is not limited to the above-described embodiment, and for example, impedance elements such as resistors may be used instead of the power receiving system and power distribution system reactors 27, 29, and various other modifications can be made.

〔Effect of the invention〕

According to the present invention described above, it is possible to switch the power supply of the power system at high speed, reduce the inrush current that occurs when switching the power supply, and reduce the transient torque of the electric motor, for example, caused by the inrush current. If there is an abnormality in the power supply switching circuit in the upper system, the power supply can be switched in the lower system.
It is possible to provide an automatic power supply switching device that can automatically supply power to systems that can be supplied with power even when the power supply switching circuit is abnormal.

[Brief explanation of the drawing]

FIG. 1 is a power system diagram showing a two-line power receiving system to which a conventional automatic power switching device is applied, and FIG. 2 is a two-line power receiving system to which an embodiment of the automatic power switching device according to the present invention is applied. 3 is a configuration diagram showing the main body of the automatic power switching device in the automatic power switching device according to the same embodiment, and FIGS. 4 and 5 show the operation of the automatic power switching device according to the same embodiment. It is a flowchart showing a procedure. 1... First power receiving switch, 2... Second power receiving switch, 3... Power receiving bus connection switch, 4... First load switch, 5... Second load switch, 6 ...first electric motor, 7...second electric motor, 8...first transformer, 9...second transformer, 10...first transformer primary switch, 11...th 2 transformer primary switch, 12... 1st transformer secondary switch, 13...
Second transformer secondary switch, 14...Distribution bus connection switch, 15...Third load switch, 16...Fourth load switch, 17...Third electric motor, 18...
...Fourth electric motor, 19...First instrument transformer,
20... second potential transformer, 21... first undervoltage relay, 22... second undervoltage relay,
23...Third potential transformer, 24...Fourth potential transformer, 25...Third undervoltage relay, 2
6... Fourth undervoltage relay, 27... Power receiving system reactor, 28... Power receiving bus connection auxiliary switch,
29... Distribution system reactor, 30... Distribution busbar contact auxiliary switch, 31... Automatic power switching device main body, 32... Power receiving system power switching circuit, 33... Abnormality detection circuit of receiving system power switching circuit, 34... ...Distribution system power supply automatic switching circuit, P1...First power receiving power supply, P2...Second power receiving power supply, B1...First power receiving bus, B2...Second power receiving bus, B11...First power receiving power supply Distribution bus, B12...Second distribution bus, F1
...First power receiving system, F11...First power distribution system, FB1...First power receiving bus system, R-F1...
...Protective relay contact, R-F11...Protective relay contact, R-FB1...Protective relay contact.

Claims (1)

[Scope of Claims] 1. A power receiving switch connected to a plurality of power receiving power sources, a power receiving bus line individually connected to these power receiving switches, and a normally open power receiving bus contact main connecting these power receiving buses. A power system with a multi-line power receiving system, which includes a switch, a distribution bus that receives power from each of the power receiving buses through the power distribution system, and a normally open main switch between the distribution buses that connects these distribution buses. A series circuit comprising an impedance element and a normally open busbar communication auxiliary switch connected in parallel to the receiving busbar communication main switch and the distribution busbar communication main switch, respectively; A power receiving system fault detection relay is provided for each power receiving power source to detect a fault on the corresponding power receiving power source and open the corresponding power receiving switch, and a power receiving system fault detection relay is provided for each of the above power receiving buses to detect a fault in the corresponding power receiving bus. A distribution system fault detection relay that opens a corresponding power receiving switch and a switch of a power distribution system connected to the power receiving bus, and an abnormality detection circuit that detects an abnormality in the power receiving bus connecting main switch and the bus connecting auxiliary switch. and a power receiving system power switching circuit that is energized by the operating signal of the power receiving system fault detection relay and sequentially turns on the power receiving bus contact auxiliary switch and the power receiving bus contact main switch, and the power receiving system when the abnormality detection circuit operates. Operates in response to at least one input of an operating signal of a system fault detection relay, an operating signal of the receiving bus fault detection relay, and an operating signal of a distribution fault detection relay, and operates the distribution bus contact auxiliary switch and the distribution bus contact main switch. An automatic power switching device characterized by comprising a distribution system power switching circuit that sequentially turns on power.