CN104218457A - Power distribution device and electric master system thereof - Google Patents

Abstract

The invention provides an electrical main system, which adopts a single-bus section wiring method, including a first section of busbar, a second section of busbar, and a first main transformer interval device connected to the first section of busbar and the second section of busbar at the same time, and the second section of busbar A first main transformer connected to the main transformer bay equipment, a second main transformer connected to the first section of the busbar, and a third main transformer connected to the second section of the busbar; the first main transformer bay equipment includes a first isolation switch and a second Isolating switch, the first isolating switch is connected to the first section of the busbar, and the second isolating switch is connected to the second section of the busbar; when the first isolating switch is closed and the second isolating switch is opened, the energy passes through the first main transformer compartment Transmission between a main transformer and the first section of bus; when the second isolating switch is closed and the first isolating switch is open, the energy is transmitted between the first main transformer and the second section of bus through the first main transformer separation equipment. The present invention also provides a power distribution device comprising the above electrical main system.

Description

A power distribution device and its electrical main system

technical field

The invention relates to the technical field of electrical engineering, in particular to an electrical main system used for a power distribution device. Furthermore, the present invention also relates to a power distribution device comprising the above-mentioned electrical main system.

Background technique

At present, electric energy has become an indispensable energy in people's life, and power plants, substations and other places, as one of the main sources of electric energy, are also one of the indispensable facilities in various places. As the main body of the power station, substation, etc., the electrical main system is used to receive and distribute electric energy in the power system. It has two wiring forms without busbar and with busbar. Among them, the wiring form with busbar can also be divided into single busbar There are two wiring forms: wiring and double busbar wiring. At the same time, no matter it is single busbar wiring or double busbar wiring, the busbars used can be segmented.

An existing electrical main system that uses single-bus section wiring, as shown in Figure 1, includes two sections of busbars—the first section of busbar 111 and the second section of busbar 112, and the first section of busbar 111 passes through the first main transformer The spacer 131 is connected to the first main transformer 121, and the second busbar 112 is connected to the second main transformer 122 and the third main transformer spacer 123 respectively through the second main transformer spacer 132 and the third main transformer spacer 133, The first bus bar 111 and the second bus bar 112 are connected to the load 16 through the outlet spacer 14, and the first bus bar 111 and the second bus bar 112 are connected by a section spacing device 15. The first bus bar 111 and the second bus bar 111 are connected to the load 16 Both busbars 112 of the second section are connected with busbar spacing equipment 18 .

When the first main transformer 121 connected to the first section of the bus 111 or the first main transformer bay equipment 131 and the section bay equipment 15 fail simultaneously, it will cause the first section of the bus 111 to lose power. At this time, only after the above-mentioned failure is repaired, the power supply of the first section of the bus 111 can be restored. If the failure cannot be processed in time to restore the power supply to the first section of the bus 111, the equipment connected to the first section of the bus 111 will be unusable. Power supply reliability is low.

Contents of the invention

In view of this, an embodiment of the present invention provides an electrical main system adopting a single-bus section connection mode, and the electrical main system improves the power supply reliability of the electrical main system. Another object of the present invention is to provide a power distribution device comprising the above electrical main system.

In order to achieve the above purpose, embodiments of the present invention provide the following technical solutions:

An electrical main system for power distribution devices, which adopts a single-bus section wiring method, is characterized in that it includes: a first-section busbar, a second-section busbar, and a first-section busbar connected to the first-section busbar and the second-section busbar at the same time A main transformer bay equipment, a first main transformer connected to the first main transformer bay equipment, a second main transformer connected to the first busbar, and a third main transformer connected to the second busbar;

Wherein, the first main transformer interval equipment includes a first isolating switch and a second isolating switch, the first isolating switch is connected to the first bus bar, and the second isolating switch is connected to the second bus bar; when the first isolating switch When the switch is closed and the second isolating switch is opened, the energy is transferred between the first main transformer and the first section of the bus through the first main transformer compartment equipment; when the second isolating switch is closed, and the second When an isolating switch is turned off, energy is transferred between the first main transformer and the second busbar through the first main transformer bay equipment.

Wherein, the electrical main system includes: segmental spacing equipment connecting the first section of busbar and the second section of busbar;

Wherein, the sectional spacer includes a bus disconnector, and when all of the bus disconnectors are closed, energy is transferred between the first section of the bus and the second section of the bus.

Wherein, the electrical main system further includes: a second main transformer bay equipment, the second main transformer bay equipment is connected between the second main transformer and the first busbar, and the second main transformer passes through Energy is transferred between the second main transformer compartment equipment and the first bus bar;

Wherein, the second main transformer bay equipment includes a bus disconnector, the bus disconnector is connected to the first section of the bus, and when the bus disconnector is closed, energy passes through the second main transformer bay The transmission between the second main transformer and the first busbar.

Wherein, the electrical main system further includes: an outlet spacer connected to the first section of the busbar and used to transfer energy with the first section of the busbar;

Wherein, the outgoing line spacing device includes a bus isolating switch, and when the bus isolating switch is closed, energy is transferred between the first section of the bus and the load through the outgoing line spacing device.

Wherein, the electrical main system further includes: a busbar spacing device connected to the first section of busbar or the second section of busbar, used to measure the Voltage.

Wherein, the first isolating switch is a remote control isolating switch.

Wherein, the number of the first main transformer is one.

Wherein, the number of the first main transformer interval device is one.

A power distribution device includes the electrical main system described above.

Wherein, the power distribution device is specifically a sulfur hexafluoride enclosed combined electrical appliance.

Based on the above technical solution, the first section of the busbar and the second section of the busbar of the electrical main system provided by the present invention are respectively connected to the same first main transformer through the first isolation switch and the second isolation switch of the first main transformer bay equipment, When the second main transformer connected to the first section of the bus or the second main transformer bay equipment and section bay equipment fail at the same time, causing the first section of the bus to lose power, the first section of the bus can be closed by controlling the first isolating switch to close the second section of the bus. A main transformer is connected to the first section of the bus, so that energy transfer is performed between the first main transformer and the first section of the bus to restore power supply. In the same way, when the second section of the bus fails due to the failure of the third main transformer or the third main transformer bay equipment and the section interval equipment at the same time, and the second section of the bus fails, the second section of the bus can be closed by controlling the second isolating switch. A main transformer is connected to the second-section bus, so that energy transfer is performed between the first main transformer and the second-section bus to restore power supply. In this way, it is possible to prevent the first busbar or the second busbar from entering a power-off state when the above-mentioned fault occurs, so that the first busbar or the second busbar is always in a charged state, and the power supply reliability of the electrical main system is improved.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only It is an embodiment of the present invention, and those skilled in the art can also obtain other drawings according to the provided drawings without creative work.

Fig. 1 is the connection mode schematic diagram of existing a kind of electrical main system;

Fig. 2 is a schematic diagram of the connection mode of the electrical main system provided by the embodiment of the present invention;

Fig. 3 is a schematic diagram of the connection mode of the first isolation device of the electrical main system provided by the embodiment of the present invention.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

Fig. 2 is a schematic diagram of the connection mode of the electrical main system provided by the embodiment of the present invention. In this embodiment, the electrical main system for the power distribution device provided by the present invention adopts a single-bus section wiring method, including: the first bus bar 211, the second bus bar 212, and the first bus bar 211 and the second bus bar 212. The first main transformer compartment equipment 231 connected to the second busbar 212 at the same time, the first main transformer 221 connected to the first main transformer compartment equipment 231, the second main transformer 222 connected to the first section busbar 211, and the second section busbar 212 connected to the third main transformer 223 .

Compared with the double-bus wiring and single-bus three-section wiring, the method of using the single-bus section wiring of the present invention optimizes the wiring form of the system, making the wiring of the secondary system in the system simpler; at the same time, due to the relative The double-bus connection uses fewer bus disconnectors and secondary equipment for the incoming and outgoing lines, and uses fewer segment spacers, bus spacer devices, and secondary equipment than the single-bus three-section connection, making the use of the single-bus segment of the present invention A wired electrical mains system can be realized with less investment.

Optionally, FIG. 3 shows a schematic diagram of the connection mode of the first isolation device of the electrical main system provided by the embodiment of the present invention. Referring to FIG. 3 , one end of the first main transformer separation device 231 is connected to the first main transformer 221 for It is connected to the first main transformer 221 for energy transfer, and the other end is connected to the first bus bar 211 and the second bus bar 212 at the same time for energy transfer to the first bus bar 211 or the second bus bar 212 .

The interior of the first main transformer bay equipment 231 includes a first isolating switch 271 and a second isolating switch 272. The first isolating switch 271 is connected to the first busbar 211, and the second isolating switch 272 is connected to the second section of the busbar 212; when the first When the isolating switch 271 is closed and the second isolating switch 272 is opened, the energy is transmitted between the first main transformer 221 and the first section of the busbar 211 through the first main transformer interval device 231. At this time, the first section of the busbar 211 is simultaneously connected to the first section of the busbar. A main transformer 221 and a second main transformer 222 are two main transformers, and the second busbar 212 is only connected to the third main transformer 223 and one main transformer; when the second isolating switch 272 is closed and the first isolating switch 271 is opened, The energy is transferred between the first main transformer 221 and the second-section bus 212 through the first main transformer interval equipment 231. At this time, the second-section bus 212 is connected to the first main transformer 221 and the third main transformer 223 at the same time. The first busbar 211 is only connected to one main transformer of the second main transformer 222 . Wherein, it should be pointed out that the first isolating switch 271 and the second isolating switch 272 cannot be closed at the same time for a long time, and only one of the first isolating switch 271 and the second isolating switch 272 can be closed each time during use; meanwhile, according to It is stipulated that the three sides (high-voltage side, medium-voltage side, and low-voltage side) of the main transformer in operation should be connected to the corresponding side equipment under normal conditions, so the first isolating switch 271 and the second isolating switch in the first main transformer compartment equipment 231 272 cannot be disconnected at the same time. Specifically, the voltages of the high-voltage side, the medium-voltage side and the low-voltage side of the operating main transformer may be 220KV, 110KV and 10KV (or 35KV) respectively.

In addition, in addition to the first isolation switch 271 and the second isolation switch 272 , the main transformer compartment equipment 231 also includes equipment such as a circuit breaker, a current transformer, and a main transformer isolation switch. The current transformer converts the primary current with a large value through the main transformer interval device 231 into a secondary current with a small value after a certain transformation based on the principle of electromagnetic induction, so as to protect the safety of the line. Regardless of whether the first isolating switch 271 and the second isolating switch 272 are closed or not, the circuit breaker and the isolating switch of the main transformer are all in the closed state unless the system fails or requires maintenance.

When the total load connected to a certain bus is relatively high, and there is only one main transformer on the bus, the load of the main transformer will be much higher than that of the other two main transformers, making the load of the three main transformers unbalanced , at this time, close the isolating switch connected to the bus bar, so that the bus bar is connected to the first main transformer 221 and another main transformer originally connected to it at the same time, so that the load carried by the main transformer originally connected to the bus bar reduce.

For example, when the total amount of load connected to the first section bus 211 is relatively high, and only the second main transformer 222 is connected to the first section bus 211, at this moment, the load carried on the second main transformer 222 will be far greater than The load carried on the first main transformer 221 and the third main transformer 223 closes the first isolating switch 271, and at the same time opens the second isolating switch 272, so that the first main transformer 221 is connected to the first busbar 211, so that the second The load carried by the second main transformer 222 is reduced; when the same situation occurs on the second section of the bus 212 , the processing method is the same as that of the first section of the bus 211 . In this way, the loads on the three main transformers can be adjusted by controlling the closing and opening of the first isolating switch 271 and the second isolating switch 272, so that the three main transformers bear relatively balanced loads respectively.

When the second main transformer 222 connected to the first section of the bus 211 or the second main transformer bay equipment 232 and the section bay equipment 25 fail simultaneously, it will cause the first section of the bus 211 to lose power. If failure can not be dealt with in time, recovery to the power supply of first section bus 211 will cause all the equipment connected on the first section bus 211 to be unusable, causing great loss. At this time, the first main transformer 221 can be connected to the first bus bar 211 by controlling the first isolating switch 271 to be closed, so that the energy transfer between the first main transformer 221 and the first bus bar 211 can be performed to restore the power supply; similarly, When the second bus bar 212 fails due to the failure of the third main transformer 223 or the third main transformer bay equipment 233 and the section bay equipment 25, etc., it will cause the second bus bar 212 to lose power. The second isolating switch 272 is closed, and the first main transformer 221 is connected to the second-section bus 212 , so that energy transfer is performed between the first main transformer 221 and the second-section bus 212 to restore power supply.

In order to know the total amount of load connected to the first bus 211 and the total load connected to the second bus 212, the bus spacer 28 is connected to the first bus 211 and the second bus 212 respectively, Figure 2. The busbar spacing equipment 28 mainly includes voltage transformers, lightning arresters, busbar isolating switches, etc., and each bus section should be connected with a busbar spacing equipment. At the same time, the busbar spacing device 28 can also be used to determine whether the first section of the bus 211 or the second section of the bus 212 to which it is connected has a power failure.

Optionally, both the first isolating switch 271 and the second isolating switch 272 can be remotely controlled isolating switches. The electrical main system in this embodiment is mainly used for power distribution devices using 110V and 220V power supply voltages, and the human body can touch The safe voltage is not higher than 36V, because the voltage used in the system far exceeds the safe voltage of the human body, if the isolating switch is used for short-distance control, there may be a danger of electric shock. On the contrary, if the isolating switch is controlled remotely, it can effectively prevent the occurrence of this safety accident, ensure personal safety, and at the same time successfully realize the function of closing the control switch.

The second main transformer 222 connected to the first busbar 211 is used for energy transfer with the first busbar 211, and the third main transformer 223 connected to the second busbar 212 is used for energy transfer with the second busbar 212. transfer.

Optionally, referring to FIG. 2 , a second main transformer separation device 232 can be set between the first section of the bus 211 and the second main transformer 222, and the second main transformer 222 is connected to the first section of the bus through the second main transformation separation device 232. 211 for energy transfer.

The second main transformer bay equipment 232 includes a group of bus disconnectors connected to the first section of the bus 211 . When the bus isolating switch is closed, energy is transferred between the second main transformer 222 and the first section of bus 211 through the second main transformer bay device 232 . In addition, the second main transformer bay equipment 232 also includes equipment such as a circuit breaker, a current transformer, and a main transformer isolation switch, in addition to the bus disconnector. When the second main transformer 222 is connected to the first section of bus 211 through the second main transformer bay device 232 and works normally, the bus disconnector, the circuit breaker and the main transformer disconnector should all be in the closed state.

When the first bus bar 211 needs to be used normally, the bus isolating switch of the second main transformer compartment equipment 232 is closed, and the first bus bar 211 and the load 26 connected to the first bus bar 211 and the bus bar spacing equipment 28 etc. are separated. Normal power supply; when it is necessary to perform power outage processing on the load 26 and bus spacing equipment 28, etc. The variable interval equipment 232 and the section interval equipment 25 are disconnected at the same time, cutting off the energy transfer between the second main transformer 222 and the second section bus 212 and the first section bus 211, so that the first section bus is powered off.

Similarly, a third main transformer bay 233 may be provided between the second busbar 212 and the third main transformer 223 , and the third main transformer 223 transmits energy to the second busbar 212 through the third main transformer bay 233 . The connection structure and functions of the third main transformer spacer 233 are the same as those of the second main transformer spacer 232 .

Optionally, referring to FIG. 2 , an outgoing line spacing device 24 may be provided in the electrical main system. One end of the outgoing line spacing device 24 is connected to the first section of the bus bar 211 and the other end is connected to the load 26 . Multiple outlet spacers 24 may be connected to the first section of the busbar 211 . The first bus bar 211 transmits energy with the load 26 through the outlet spacer 24 .

The outgoing line separation device 24 includes a bus disconnector, and the bus disconnector is connected to the first section of the bus 211 . When the bus isolating switch is disconnected, the load 26 connected to the outgoing line spacing device will not be connected to the first section of the bus 211 for energy transfer; when the bus isolating switch is closed, the outgoing line spacing device 24 will be the first The energy transferred by a section of busbar 211 is transferred to the load connected to the outlet spacer. In addition, the outgoing line separation equipment 232 also includes equipment such as a circuit breaker, a current transformer, and an outgoing line isolating switch in addition to the bus disconnector. When the load 26 transmits energy to the first section of the busbar 211 through the outlet spacer 24, the bus disconnector, the circuit breaker and the outlet disconnector should all be in the closed state.

When the load 26 connected to the first section bus 211 needs to be used normally, the outlet spacer 24 is closed, and the load 26 connected to the first section bus is normally powered; when it is necessary to connect to the first section bus 211 The load 26 etc. of the load 26 etc. carry out power outage, for example maintenance, and when needing not to connect the bus bar interval equipment 28 etc. on the first section bus bar 211 and being connected on the first section bus bar 211 etc. to carry out power outage, disconnect the outgoing line interval equipment 24, cut off the first section bus bar 211 etc. The energy transfer between a section of busbar 211 and load 26, etc., reserves the energy transfer between the second main transformer 222 and the first section of busbar 211, and the interval between the first section of busbar 211 and other outgoing lines, etc., so that the load 26, etc. are powered off and the first section The busbar 211 and the busbar spacing equipment 28 are not powered off. Adding the outgoing line interval device 24 can only need to cut off the power of the load that needs to be repaired when the load and the like need to be repaired, and does not need to cut off the power of the whole section of the bus, which ensures the normal operation of other devices on the bus.

Similarly, the outgoing line spacer 24 can also be connected to the second section bus 212, one end of the outgoing line spacer 24 is connected to the second section bus 212, and one end is connected to the load 26, and the second section bus 212 is connected to the load 26 through the outgoing line spacer 24. energy transfer between them.

Optionally, referring to FIG. 2 , there is a section spacer 25 connected between the first section bus 211 and the second section bus 212 , and the first section bus 211 can transfer energy to the second section bus 212 through the section spacer 25 , similarly, the second section of busbar 212 can transmit energy to the first section of busbar 211 through the section spacer 25 .

The section spacer 25 includes two sets of bus disconnectors. When all the bus disconnectors are closed, mutual energy transfer is performed between the first section bus and the second section bus. When the second main transformer 222 breaks down or the second main transformer bay equipment 232 breaks down, it will cause the first busbar 211 to be powered off, and the section bay equipment 25 will be closed, and the section bay equipment 25 will transfer the energy of the second section busbar 212 To the first section bus 211, the first section bus 211 is restored to the charged state; in the same way, when the third main transformer 223 breaks down or the third main transformer interval equipment 233 breaks down, it will cause the second section bus 212 to be powered off, Close the sectional spacer 25, and the sectional spacer 25 transfers the energy of the first section of the bus 211 to the second section of the bus 212, so that the second section of the bus 212 returns to the electrified state. In addition, in addition to the bus disconnector, the segmental spacer 25 also includes a circuit breaker and a current transformer. When the first busbar 211 transmits energy to the second busbar 212 through the segmental spacing device 25, the busbar disconnector and circuit breaker should both be closed.

According to the above-mentioned embodiment, when a certain section of the first section of bus 211 and the second section of bus 212 has a power outage fault, here, taking the first section of bus 211 having a failure and the second section of bus 212 having a normal power supply as an example, In the electrical main system, there are two ways to restore the first section of the bus 211 to the electrified state by closing the switchgear of the section bay equipment 25 and closing the first isolation switch 271 of the first main transformer bay equipment 231 . Here, it is preferred to first close the switchgear of the sectional spacer 25 to restore the electrified state to the first bus bar 211. If the switchgear of the sectional spacer 25 is closed, the first bus bar 211 can be restored to an electrified state. , it can avoid the situation that the first main transformer is powered off, even if the electrical main system resumes normal operation, the utilization rate of resources is improved. If the section separation equipment 25 breaks down, then choose to close the first isolating switch 271 of the first main transformer separation equipment 231 to restore the first busbar 211 to the electrified state.

It should be noted that when the embodiment of the present invention is shown in Figure 2 as a 220kV wiring diagram, the energy is transferred from the outlet side to the main transformer side through the busbar, that is, the energy is transferred from the load 26 to the busbar through the outlet spacing device 24, and then the busbar passes through the first A spacer 231, a second spacer 232 and a third spacer 233 transmit to the first main transformer 221, the second main transformer 222 and the third main transformer 223 respectively; , the energy is transferred from the main transformer side to the outgoing line side through the bus bar, that is, the energy is passed through the bus bar by the first main transformer 221, the second main transformer 222 and the third main transformer 223 respectively through the first spacer 231, the second spacer 232 and the second spacer. The three-spaced equipment 233 transmits to the busbar, and then the busbar transmits to the load 26 through the outgoing line spaced equipment 24.

In addition to the above electric main system, the present invention also provides a power distribution device, which includes the above electric main system. For other parts of the power distribution device, please refer to the prior art, which will not be repeated here.

Specifically, the above-mentioned power distribution device may be a sulfur hexafluoride enclosed combined electrical appliance (GIS equipment, also known as gas-insulated metal-enclosed switchgear).

Since the SF6 closed combined electrical appliance adopts the gas chamber separation structure, when the fault is repaired in the GIS equipment, it is necessary to decompress the gas chamber adjacent to the fault point. If the double busbar wiring method is used, it will cause Power failure at fault intervals, and when expanding the intermediate interval equipment of GIS equipment, due to the need to carry out withstand voltage tests on GIS equipment, then, even if the busbar isolating switch has been installed in the early stage, it is also necessary to conduct power outages on the double busbars, thus As a result, all GIS equipment is powered off, and GIS equipment cannot reflect the advantages of double busbars. In the previous specific examples, we can know that using the single-bus section wiring method in the embodiment of the present invention can effectively reduce troubleshooting and reduce power outage time when using sulfur hexafluoride closed combination appliances And avoid the power distribution device full power failure during expansion, improve the reliability of power supply, it can also be seen from here that the improvement of the present invention makes the improved single-bus section wiring better than the double-bus scheme.

Each embodiment in this specification is described in a progressive manner, each embodiment focuses on the difference from other embodiments, and the same and similar parts of each embodiment can be referred to each other. As for the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and for the related information, please refer to the description of the method part.

The above description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention will not be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (10)

1. An electrical main system for a power distribution device, which adopts a single bus section wiring method, is characterized in that it includes: a first section busbar (211), a second section busbar (212), and a first section busbar ( 211) and the first main transformer bay equipment (231) connected simultaneously with the second section busbar (212), the first main transformer (221) connected with the first main transformer bay equipment (231), and the first section busbar (211 ) connected to the second main transformer (222), and the third main transformer (223) connected to the second busbar (212); wherein, The first main transformer compartment equipment (231) includes a first isolating switch and a second isolating switch, the first isolating switch is connected to the first bus bar (211), and the second isolating switch is connected to the second bus bar (212) ; when the first isolating switch is closed and the second isolating switch is disconnected, the energy passes through the first main transformer interval equipment (231) between the first main transformer (221) and the first section bus ( 211); when the second isolating switch is closed and the first isolating switch is opened, the energy passes through the first main transformer spacer (231) between the first main transformer (221) and the first main transformer (221) Transfer between the two busbars (212). 2. The electrical main system according to claim 1, characterized in that, the electrical main system comprises: a sectional spacer (25) connecting the first section of the busbar and the second section of the busbar; wherein, The sectional spacer (25) includes a bus isolating switch, and when all of the bus isolating switches are closed, energy is transferred between the first section of the bus (211) and the second section of the bus (212) . 3. The electrical main system according to claim 1, further comprising: a second main transformer interval device (232), and the second main transformer interval device (232) is connected to the second main transformer ( 222) and the first busbar (211), the second main transformer (222) transfers energy between the second main transformer interval equipment (232) and the first busbar (211); wherein, The second main transformer compartment equipment (232) includes a bus isolating switch connected to the first section of the bus (211), when the bus isolating switch is closed, energy passes through the second main The variable interval equipment (232) is transmitted between the second main transformer (222) and the first busbar (211). 4. The electrical main system according to claim 1, characterized in that, it further comprises: an outlet spacer connected to the first section of the busbar (211) for transferring energy with the first section of the busbar (211) (24); where, The outlet spacer (24) includes a bus isolating switch, when the bus isolator is closed, energy is transferred between the first section of the bus (211) and the load (26) through the outlet spacer (24) . 5. The electrical main system according to claim 1, characterized in that, it further comprises: a busbar spacing device (28) connected to the first busbar (211) or the second busbar (212), for for measuring the voltage of the first bus bar (211) or the second bus bar (212) connected thereto. 6. The electrical main system according to claim 1, wherein the first isolating switch is a remote control isolating switch. 7. The electrical main system according to claim 1, characterized in that the number of the first main transformer (221) is one. 8. The electrical main system according to claim 7, characterized in that the number of the first main transformer spacer (231) is one. 9. A power distribution device, comprising the electrical main system according to any one of claims 1-8. 10. The power distribution device according to claim 9, characterized in that, the power distribution device is a sulfur hexafluoride closed combination electrical appliance.