CN206259716U - A kind of new electrical main connecting wire of transformer station - Google Patents

Abstract

The utility model provides a new electrical main connection of a substation, which includes at least one power electronic transformer, and the low-voltage AC side of the power electronic transformer can directly lead out one or more AC outgoing lines without a circuit breaker. The main wiring directly leads one or more AC outgoing lines from one or more parallel medium and low voltage DC-AC converters through the low-voltage AC side of the power electronic transformer, so as to realize the direct connection of one or more AC outgoing lines on the low-voltage AC side of the power electronic transformer. Feed-out, no confluence bus, saves the AC bus, avoids the failure of all outgoing lines due to bus failure, and improves the reliability of power supply; the low-voltage DC bus drawn from the low-voltage DC side of the power electronic transformer in the main wiring, The low-voltage DC bus is connected to DC load equipment or DC power supply to realize flexible access to DC loads or energy storage equipment in substations and mixed power supply to AC and DC loads.

Description

A New Electrical Main Wiring for Substation

technical field

The utility model relates to the technical field of electric power, in particular to a new electrical main connection of a substation.

Background technique

With the accelerated pace of smart grid construction, power electronics technology and devices are increasingly widely used in substations. The reliability and flexibility of electrical main wiring characterized by power electronics primary equipment is particularly important for the operation of substations.

At present, in the main wiring of the substation, the low-voltage AC output is generally connected to the busbar, and then multiple outgoing lines drawn from the busbar are connected to the load equipment or power supply equipment, and a breaking device is set in each outgoing line. A typical electrical main wiring of a substation fed by a low-voltage AC busbar is shown in Figure 1. Among them, the high-voltage AC side of the power electronic transformer 1 is connected to the high-voltage AC bus 2, and then connected to the AC terminal 11 through the breaking device 3; the low-voltage AC side of the power electronic transformer 1 is connected to the low-voltage AC bus 7 through the breaking device 8, Then connect the AC outlet 9. It can be seen that when the low-voltage AC bus fails, all outgoing lines will lose power. At the same time, the possible fault points increase accordingly, making it difficult to meet the construction and development needs of substations.

On the other hand, the main terminal station of the existing substation is usually connected to loads or energy storage devices in the form of AC outlets. For DC loads or energy storage devices, it is difficult to achieve flexible access.

Therefore, it is necessary to provide a highly reliable main wiring form.

Utility model content

The first technical problem to be solved by the utility model is to overcome the defects in the existing substations that all outgoing lines lose power and the number of outgoing circuit breakers is too large due to a bus failure;

In addition, the second technical problem to be solved by the utility model is that the main wiring of the existing substation is usually connected to the load or energy storage equipment through the AC outgoing line, and it is difficult to realize the defect of flexible access to the DC load or energy storage equipment.

In view of this, the utility model provides a new type of electrical main wiring of a substation, including at least one power electronic transformer, the high-voltage AC side of the power electronic transformer is connected to the high-voltage AC bus, and the feature is that the low-voltage of the power electronic transformer The AC side leads directly to one or more AC outgoing lines, and the low-voltage DC side of the power electronic transformer leads to a low-voltage DC bus.

Preferably, the power electronic transformer includes at least a high-voltage AC-DC converter, a high-voltage DC-AC converter, a medium-high frequency transformer, a medium-low voltage AC-DC converter, a medium-low voltage DC-AC converter, the The low-voltage AC side and the low-voltage DC side of the power electronic transformer are respectively led out from the medium-low voltage DC-AC converter, and the high-voltage AC side of the power electronic transformer is led out from the high-voltage AC-DC converter.

Preferably, a first breaking device is provided between the low-voltage DC side of the power electronic transformer and the low-voltage DC bus.

Preferably, the low-voltage DC bus is also connected to one or more DC terminals, and a second breaking device is provided between the low-voltage DC bus and each DC terminal.

Preferably, the DC terminal is connected to a DC load device.

Preferably, the DC terminal is connected to a DC power supply.

Preferably, the high-voltage AC bus is connected to one or more AC terminals, and a third breaking device is provided between the high-voltage AC bus and each AC terminal.

Preferably, part or all of the first breaking device or the second breaking device or the third breaking device uses a power electronic quick breaking device or a conventional circuit breaker.

Preferably, the low-voltage AC side of the power electronic transformer leads directly to one or more AC outgoing lines from one of the medium-low voltage DC-AC converters.

Preferably, the low-voltage AC side of the power electronic transformer leads directly to one or more AC outgoing lines from a plurality of parallel-connected medium and low-voltage DC-AC converters.

The technical scheme of the utility model has the following advantages:

1. The utility model provides a new type of electrical main wiring of a substation, including at least one power electronic transformer. The low-voltage AC side of the power electronic transformer can directly lead to one or more AC outlets without a circuit breaker. The main wiring directly leads one or more AC outgoing lines from one or more parallel medium and low voltage DC-AC converters through the low-voltage AC side of the power electronic transformer, so as to realize the direct connection of one or more AC outgoing lines on the low-voltage AC side of the power electronic transformer. Feed-out, no need for converging busbars, eliminating the need for AC busbars, avoiding the loss of power for all outgoing lines due to busbar failures, and improving power supply reliability; at the same time, because power electronic devices can block faults in a very short time (microseconds) Therefore, the medium and low voltage DC-AC converter also has the function of a circuit breaker, so that the feeder circuit breaker can be omitted, which not only reduces the number of circuit breakers as a whole, but also reduces possible fault points.

2. The utility model provides a new type of electrical main wiring of a substation. The low-voltage DC bus bar can be led out from the low-voltage DC side of the power electronic transformer in the main wiring, and connected to the DC load equipment or DC power supply through the low-voltage DC bus bar to realize the DC load of the substation. Or flexible access of energy storage equipment and mixed power supply to AC and DC loads.

Description of drawings

In order to more clearly illustrate the specific implementation of the utility model or the technical solutions in the prior art, the accompanying drawings that need to be used in the description of the specific implementation or the prior art will be briefly introduced below. Obviously, the following descriptions The accompanying drawings are some implementations of the utility model, and those skilled in the art can also obtain other drawings according to these drawings without any creative work.

Figure 1 is a schematic diagram of the electrical main wiring of a substation fed by a low-voltage AC busbar;

Figure 2 is a schematic diagram of a new type of electrical main wiring of a substation with low-voltage AC direct feed-in;

Fig. 3 is a schematic structural diagram of a power electronic transformer including a medium and low voltage DC-AC converter;

Fig. 4 is a schematic structural diagram of a power electronic transformer including a plurality of medium and low voltage DC-AC converters connected in parallel.

Wherein, reference sign is:

1-Power Electronic Transformer, 2-High Voltage AC Bus, 3-Third Breaking Device, 4-Low Voltage DC Bus, 5-First Breaking Device, 6-Second Breaking Device, 7-Low Voltage AC Bus, 8- Breaking device, 9-low-voltage AC outlet, 10-low-voltage DC terminal, 11-high-voltage AC terminal;

30-medium and high frequency transformer, 31-high voltage AC-DC converter,

32-High-voltage DC-AC converter, 33-High-voltage AC side, 34-Low-voltage DC side,

35-Middle and low voltage AC-DC converters, 36-Middle and low voltage DC-AC converters,

37-Low-voltage AC side.

detailed description

The technical solutions of the utility model will be clearly and completely described below in conjunction with the accompanying drawings. Apparently, the described embodiments are part of the embodiments of the utility model, but not all of them. Based on the embodiments of the present utility model, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the scope of protection of the present utility model.

In the description of the present utility model, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" The orientation or positional relationship indicated by etc. is based on the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, use a specific The azimuth structure and operation, therefore can not be construed as the limitation of the present utility model. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and should not be construed as indicating or implying relative importance.

In the description of the present utility model, it should be noted that, unless otherwise clearly stipulated and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection or a flexible connection. Detachable connection, or integral connection; it can be mechanical connection or electrical connection; it can be direct connection or indirect connection through an intermediary, or it can be the internal communication of two components, it can be wireless connection, or it can be wired connection. Those of ordinary skill in the art can understand the specific meanings of the above terms in the present utility model in specific situations.

In addition, the technical features involved in different embodiments of the present invention described below can be combined with each other as long as they do not constitute conflicts with each other.

This embodiment provides a new type of electrical main wiring of a substation with low-voltage AC direct feed-in, as shown in FIG. 2 . The main wiring includes a power electronic transformer 1, the high-voltage AC side of the power electronic transformer 1 is connected to the high-voltage AC bus 2, the low-voltage AC side of the power electronic transformer 1 directly leads to one or more AC outlets 9, and the low-voltage DC of the power electronic transformer 1 The low-voltage DC bus 4 is led out from the side.

Specifically, the internal structure of the power electronic transformer 1 is shown in FIG. 3 . The power electronic transformer 1 adopts multiple converter devices, and the connection sequence from the high-voltage side to the low-voltage side is as follows: high-voltage AC-DC converter 31, high-voltage DC-AC converter 32, medium-high frequency transformer 30, medium-low voltage AC- A DC converter 35 and a medium and low voltage DC-AC converter 36 . The low-voltage AC side 37 and the low-voltage DC side 34 of the power electronic transformer 1 are respectively derived from the medium-low voltage DC-AC converter 36 , and the high-voltage AC side 33 is derived from the high-voltage AC-DC converter 31 . As a preferred embodiment, a plurality of medium and low voltage DC-AC converters 36 connected in parallel (as shown in FIG. 4 ) are arranged according to the output capacity, and the low voltage AC side 37 is directly led out.

The low-voltage DC side 34 of the power electronic transformer 1 is led out from the medium-low voltage DC-AC converter 36 to provide a low-voltage DC electrical interface and realize flexible access to DC loads or energy storage devices.

The main wiring directly leads one or more AC outgoing lines from one or more parallel medium and low voltage DC-AC converters through the low-voltage AC side of the power electronic transformer, so as to realize the direct connection of one or more AC outgoing lines on the low-voltage AC side of the power electronic transformer. Feed-out, without confluence bus, saves the AC bus, avoids the situation that all outgoing lines lose power due to bus failure, and improves the reliability of power supply; the low-voltage DC bus is drawn from the low-voltage DC side of the power electronic transformer, and connected to the DC bus through the low-voltage DC bus DC load equipment or DC power supply can be input into the substation to realize flexible access to DC load or energy storage equipment and hybrid power supply to AC and DC loads. At the same time, since the power electronic device can block the fault current in a very short time (microseconds), the medium and low voltage DC-AC converter also has the function of a circuit breaker, so that the feeder circuit breaker can be omitted, not only the overall The number of circuit breakers is reduced, and possible failure points are reduced.

A first breaking device 5 is arranged between the low-voltage DC side of the power electronic transformer 1 and the low-voltage DC bus 4 . Preferably, the blocking function of the medium and low-voltage DC-AC converter 36 can also be used to realize the breaking between the low-voltage DC side of the power electronic transformer 1 and the low-voltage DC bus 4 , so the first breaking device 5 may not be provided.

The low-voltage DC bus 4 is also connected to one or more DC terminals 10 , and a second breaking device 6 is provided between the low-voltage DC bus 4 and each DC terminal 10 . The DC terminal 10 can be connected to a DC load device, and can also be connected to a DC power source, so as to realize flexible access of the substation to DC loads or energy storage devices and mixed power supply to AC and DC loads.

As a specific implementation, the high-voltage AC bus 2 can be connected to one or more AC terminals 11 , and a third breaking device 3 is provided between the high-voltage AC bus 2 and each AC terminal 11 .

The first breaking device 5, the second breaking device 6 and the third breaking device 3 can partially or completely use power electronic quick breaking devices or conventional circuit breakers according to needs, so power electronic quick breaking devices can be used partly, and partly Use conventional circuit breakers. When the power electronic quick disconnect device is used, the quick removal of the fault can be realized.

As a specific implementation manner, the main connection may also be provided with multiple power electronic transformers. A plurality of power electronic transformers are connected in parallel, and the wiring mode of each power electronic transformer is as shown above, which will not be repeated here. The use of power electronic transformers can realize comprehensive control functions such as two-way on-demand deployment of power flow, active and reactive composite support, power quality isolation and control, and fault current limiting.

Apparently, the above-mentioned embodiments are only examples for clear description, rather than limiting the implementation. For those of ordinary skill in the art, on the basis of the above description, other changes or changes in different forms can also be made. It is not necessary and impossible to exhaustively list all the implementation manners here. And the obvious changes or variations derived therefrom are still within the scope of protection of the utility model.

Claims (10)

1. A new electrical main wiring of a substation, comprising at least one power electronic transformer, the high-voltage AC side of the power electronic transformer is connected to a high-voltage AC busbar, and it is characterized in that the low-voltage AC side of the power electronic transformer directly leads to one or A plurality of AC outgoing lines, and the low-voltage DC side of the power electronic transformer leads to a low-voltage DC bus. 2. The main wiring according to claim 1, wherein the power electronic transformer includes at least a high-voltage AC-DC converter, a high-voltage DC-AC converter, a medium-high frequency transformer, and a medium-low voltage AC-DC converter The low-voltage DC-AC converter, the low-voltage AC side and the low-voltage DC side of the power electronic transformer are respectively drawn from the medium-low voltage DC-AC converter, and the high-voltage AC side of the power electronic transformer is drawn from the High-voltage AC-DC converter leads. 3. The main connection according to claim 2, characterized in that a first breaking device is provided between the low-voltage DC side of the power electronic transformer and the low-voltage DC bus. 4. The main connection according to claim 2, wherein the low-voltage DC bus is also connected to one or more DC terminals, and a second switch is provided between the low-voltage DC bus and each DC terminal. disconnect device. 5. The main wiring according to claim 4, wherein the DC terminal is connected to a DC load device. 6. The main wiring according to claim 4, wherein the DC terminal is connected to a DC power supply. 7. The main connection according to any one of claims 1-6, characterized in that, the high-voltage AC busbar is connected to one or more AC terminals, and between the high-voltage AC busbar and each AC terminal A third breaking device is provided. 8. The main wiring according to claim 7, characterized in that, part or all of the first breaking device or the second breaking device or the third breaking device uses a power electronic quick breaking device or a conventional breaking device device. 9. The main wiring according to claim 2, wherein the low-voltage AC side of the power electronic transformer leads directly to one or more AC outgoing lines from one of the medium-low voltage DC-AC converters. 10. The main wiring according to claim 2, wherein the low-voltage AC side of the power electronic transformer leads directly to one or more AC outgoing lines from a plurality of parallel-connected medium and low-voltage DC-AC converters.