A mobile electric energy channel transmission device and a method of using the same

Abstract

To solve the problem that the flexible direct current equipment in the prior art cannot realize automatic control and adjustment, and cannot be used continuously for a long time. The present disclosure provides a mobile electric energy channel transmission device, which realizes the extraction of electric energy from the transformer of the adjacent substation through the flexible direct current interconnection device to supply power to the heavily overloaded substation, and reversely sends the electric energy extracted from the heavily overloaded substation to supply power to the adjacent substation. In order to achieve the above technical effect, the present invention includes a box body, and the box body is provided with two direct current conversion units, each direct current conversion unit structure includes a power conversion unit connected to different substations, and each power conversion unit is connected to a main controller. The overall structure of the product of the present invention is smaller than any existing vehicle-mounted flexible direct current system. One device can serve multiple blocks at different times. When the main controller of the present invention is not connected to the power business platform, it can also actively start and stop through the built-in operation strategy, realizing unmanned and safe operation.

Description

Technical Field

[0001] The present disclosure relates to a flexible direct current device for electric power, and more particularly to a mobile electric energy channel transmission device and a method for using the device. Background Art

[0002] With the seasonal peak of electricity consumption such as air conditioning, and the access of unbalanced sources such as charging piles and photovoltaics, problems such as heavy overload and reverse heavy overload in the substation area have become prominent. Simply increasing capacity and filling points can no longer meet the needs of the new power system environment, and the cost is too high, and it increases transformer losses, which is not conducive to the realization of the dual carbon goals. On the other hand, the substation area adjacent to the heavy overload often has residual transformer capacity that can be tapped, and an easily deployable power channel transmission device is urgently needed to solve the above contradictions.

[0003] The applicant has been studying the corresponding flexible direct current system. An invention patent with patent application number: 202210529515.5 "A mobile flexible direct current power transfer vehicle and its use method" has also been applied for. The invention records a mobile flexible direct current power transfer vehicle and its use method, wherein the mobile flexible direct current power transfer vehicle comprises a first AC-DC power electronic converter, a second AC-DC power electronic converter, an interface module and a control module. The first AC-DC power electronic converter and the second AC-DC power electronic converter are both connected to the control module through the interface module, and are respectively connected to the substation for power transfer and the substation for receiving power transfer, and the control module is wirelessly connected to the power business platform. The use method specifically detects the operating status of the substation, determines the access substation of the mobile flexible direct current power transfer vehicle, deploys the mobile flexible direct current power transfer vehicle to the corresponding access position, obtains power data in the substation, determines the operation mode and adjustment content, and the first AC-DC power electronic converter and the second AC-DC power electronic converter are adjusted according to the adjustment content. The invention can make the power transfer between substations more flexible and effectively improve the utilization efficiency of flexible direct current equipment.

[0004] However, as a vehicle-mounted device, the invention still has some defects. First of all, the entire adjustment process still needs to be managed by the power business platform, and automatic control and adjustment cannot be achieved. At the same time, the vehicle-mounted equipment has shortcomings in terms of stay time limit and continuous operation, and the vehicle itself needs maintenance. Therefore, the technology in the prior art is only suitable for short-term use, such as supporting large-scale performances, events, etc., but not for certain long-term needs. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a mobile power channel transmission device, which uses a set of updated power equipment to realize the extraction of power from the adjacent transformer area through the flexible DC interconnection device to supply power to the heavily overloaded transformer area, and reversely sends the power extracted from the heavily overloaded transformer area to supply power to the adjacent transformer area. The device as a whole is also easy to install, disassemble and move.

[0006] In order to achieve the technical effect, the specific technical solution adopted by the present invention is: a mobile electric energy channel transmission device, including a box, at least two DC conversion units are arranged in the box, each DC conversion unit has the same structure, and includes a power conversion unit, the DC ends of the power conversion units in each DC conversion power supply are reversely connected to each other to achieve AC / DC and DC / AC conversion, the AC ends of each power conversion unit are respectively connected to different substations, each power conversion unit is respectively connected to a main controller, multiple main controllers are connected to each other, and the other end of the main controller is connected to the fusion terminal through a collector

[0007] Preferably, the AC end of the power conversion unit is connected to the substation via an AC circuit breaker. The AC circuit breaker serves as a protection device to ensure safety during operation.

[0008] Preferably, a bidirectional meter is provided between the power conversion unit and the AC circuit breaker, and the external AC power is converted into DC power through the bidirectional meter to the power conversion unit.

[0009] Preferably, the box is installed between multiple transformers in a power distribution room or between branches at the end of a transformer area.

[0010] Preferably, the box outlet has a separate junction box with a plug-and-play socket, and the low-voltage cable is connected at the junction box. In order to ensure that the AC outlet of the equipment is easy to install and disassemble. The wiring needs to ensure phase isolation to prevent short circuits.

[0011] Preferably, the two main controllers are connected to each other via 485 / CAN communication to realize the power scheduling of the substation area independently; the main controller communicates with the fusion terminal or concentrator via carrier or micro-power wireless using 645 protocol.

[0012] The present invention also includes a working method of a mobile electric energy channel transmission device. After the main controller collects the total meter current through the fusion terminal or concentrator, it sends the total meter current data to the device after a specified time interval through the carrier / micropower wireless. The mutual aid device determines whether to start mutual aid by itself, starts working when the mutual aid conditions are met, and stops working when the shutdown conditions are met. This ensures that the device is not always in working state, and achieves the effect of working on demand.

[0013] Preferably, the two DC conversion units are connected to the first station area and the second station area respectively, and the starting condition for the power channel transmission device to start working is:

[0014] When the load rate of any area exceeds β weight and the load rate difference (βmax-βmin) exceeds the first start limit, or the area load rate is greater than the difference between β weight and the first start limit and less than β weight, or the load rate difference exceeds the second start limit.

[0015] Furthermore, the scheduling target after startup is that the difference in load rates of the two transformers is less than 5%, providing energy at the lowest load rate to the highest load rate; when the capacity to be scheduled exceeds the capacity of the equipment, the equipment outputs according to its maximum capacity.

[0016] Furthermore, the conditions for stopping the operation of the electric energy channel transmission device include: the load rate of all stations is lower than β weight minus the first startup limit; or at least one station load rate is greater than β weight minus the first startup limit and less than β weight; or the difference in load rates of each station (βmax-βmin) is less than the second startup limit; or the load rate of one station exceeds β weight, and the deviation of the load rate of each station (βmax-βmin) is less than the first startup limit. In each link, the first startup limit and the second startup limit can be preset in the main controller, and the value of the second startup limit is twice the first startup limit. The first startup limit is usually 10%-15% of the station load rate. If it is lower than 10%, the startup effect is not obvious, and it is difficult to allocate and control after it is higher than 15%.

[0017] Compared with the prior art, the present invention is more compact in terms of overall structure, and the actual product volume is smaller than any existing vehicle-mounted flexible direct current system. The entire device is also fixedly placed in a designated distribution room between multiple transformers, between branches at the end of the distribution area, and other locations. It can be installed when needed and can be dismantled and moved to other nearby locations when idle. One device can serve multiple blocks at different times.

[0018] In addition, when the main controller of the present invention is not connected to the power business platform, it can also be actively started and stopped through the built-in operation strategy, thereby realizing unmanned and safe operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings illustrate exemplary embodiments of the present disclosure and together with the description serve to explain the principles of the present disclosure. These drawings are included to provide a further understanding of the present disclosure and are incorporated in and constitute a part of this specification.

[0020] Figure 1 It is a schematic diagram of the internal structure of a mobile electric energy channel transmission device of the present invention.

[0021] Figure 2 It is a schematic diagram of the start-stop relationship of an embodiment of a mobile electric energy channel transmission device of the present invention. DETAILED DESCRIPTION

[0022] The present disclosure is further described in detail below in conjunction with the accompanying drawings and implementations. It is understood that the specific implementations described herein are only used to explain the relevant content, rather than to limit the present disclosure. It should also be noted that, for ease of description, only the parts related to the present disclosure are shown in the accompanying drawings.

[0023] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in the present disclosure may be combined with each other. The present disclosure will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0024] The present invention relates to a concept of a substation β. The substation β in the power system refers to the magnitude of frequency fluctuation caused by the fluctuation of the substation load, which can usually be regarded as the transformer load rate. It is a parameter to measure the influence of the substation on the frequency stability.

[0025] β=I2 / I2N

[0026] I2, transformer load current; I2N, transformer secondary rated current

[0027] The calculation formula of the area β is:

[0028] β=ΔP / Δf=ΔPW / S / Δf

[0029] in:

[0030] ΔP: load change in the substation, in MW;

[0031] Δf: system frequency change, in Hz;

[0032] S: rated capacity of the substation, in MVA;

[0033] ΔPW: power fluctuation in the substation, equal to the load change ΔP, in MW.

[0034] The larger the β of the substation, the greater the impact of the load fluctuation of the substation on the system frequency, and the higher the difficulty of regulating the substation. Therefore, the power dispatcher will pay close attention to the β of each substation during operation to avoid load fluctuations in the substation with excessive β to ensure the stability of the system frequency.

[0035] Generally speaking, the substation with β between 5% and 15% has little impact on the system frequency; for the substation with β exceeding 20%, its load fluctuation will have a greater impact on the system frequency. The scheduling of such substation is more difficult, and special measures need to be taken to improve its regulation capability and system stability.

[0036] The β-weight mentioned in the present invention refers to the heavy load rate, which is generally 80%;

[0037] The one with higher load rate among the two distribution transformers is βmax, and the one with lower load rate is βmin.

[0038] Therefore, in summary, the β of the substation in the power system refers to the proportional impact of the substation load fluctuation on the change in the grid frequency. It is an important parameter to measure the impact of the substation on the system frequency stability. In the present invention, the main controller also implements different operating strategies according to the size of the β of each substation.

[0039] The load factor refers to the ratio of the load power in the substation (including the power provided by the transformer and the power provided by the mutual aid equipment) to the transformer capacity.

[0040] like Figure 1 The figure shows a mobile electric energy channel transmission device of the present invention, including a box body, in which two DC conversion units are arranged, each DC conversion unit has the same structure, and includes a power conversion unit, the DC ends of the power conversion units in the two DC conversion power supplies are reversely connected to each other to realize the conversion of AC / DC and DC / AC, the AC ends of the two power conversion units are respectively connected to two different substations, and the AC ends of the power conversion units are connected to the substations through AC circuit breakers. A bidirectional meter is also arranged between the power conversion unit and the AC circuit breaker, and the external AC power is converted into DC through the bidirectional meter to the power conversion unit. The two power conversion units are each connected to a main controller, and the two main controllers are connected to each other, and the other end of the main controller is connected to the fusion terminal through a collector. Although the main disclosed and successfully realized in the present invention is a finished product with two DC conversion units, in theoretical application, an actual single mobile electric energy channel transmission device can realize diversified processing of up to 8 substations.

[0041] The box needs to be customized according to actual needs. The box has reserved installation positions for electric meters and transformers. The box outlet has a separate junction box with a plug-and-play socket, and the low-voltage cable is connected at the junction box. In actual application, the box is installed between multiple transformers in the distribution room or between branches at the end of the distribution area.

[0042] In the whole device, communication is the premise to ensure the normal operation of the device. In the present invention, the two main controllers are connected to each other through 485 / CAN communication to realize the power dispatch of the substation area by themselves; the main controller communicates with the fusion terminal or concentrator through carrier or micro-power wireless using 645 protocol.

[0043] Example 1, in order to transfer the commercial and air-conditioning loads in the urban village and alleviate the overload problem of the substation, the applicant uses a mobile power channel transmission device of the present invention between the 2# distribution 1 transformer 4-row branch household connection line and the Jiangmashanbei 1# distribution 2 transformer 3-row branch household connection line. The ends of the interconnection lines of the three substations of Jiangmashanbei 1#2#3# are suitable for mutual assistance and have been installed with AC400V low-voltage cable quick-plug female connectors. Through the two sets of AC400V low-voltage cable quick-plug female connectors with the mutual assistance device, it is ensured that the power cable is quickly connected to the self-starting mode. The flexible transfer of commercial, small workshops and air-conditioning loads in the substation area is realized. The specific process is:

[0044] Main controller setting parameters:

[0045] (1) Transformer capacity se1, se2, se3, unit: kVA

[0046] (2) Load rate threshold β t1 , β t2 , where β t2 <β t1 , β t1 Default 85%, β t2 Default 70%

[0047] (3) Multi-station load factor difference threshold β dt1 , β dt2 , where β dt2 Default 20%, β dt1 Default 10%

[0048] (4) Equipment capacity P 01 , P 02 , P 03

[0049] (5) Scheduling period T, unit: s (master station T = 15 min, carrier T = 1 min, 485T = 2 s).

[0050] Specific process:

[0051] (1) The main controller detects the three-phase current and voltage at the transformer outlet detected by the mutual aid equipment in the three substations respectively, and obtains the apparent power S1, S2, and S3 in kVA

[0052] (2) Call the mutual aid equipment in the three substations to obtain the total operating power P of the equipment c1 , P c2 , P c3 , unit kW, data type is a signed number (taking energy from the station is positive, sending energy to the station is negative)

[0053] (1) Calculate the capacity ratio of the three-zone transformers (only one calculation is required)

[0054]

[0055] (2) Calculate the current actual load rate of the Santai area

[0056]

[0057] (3) Calculate reference value

[0058] The operating reference values ​​that the three-zone equipment needs to receive are P1, P2, and P3 (unit: kW). The data type is a signed number. Reactive power is ignored during the calculation process. Conditions 1, 2, and 3 are in a "logical and" relationship. The calculation method is as follows: Figure 2 shown.

[0059] In this embodiment, the first startup limit is set to a total load rate of 10%, and the second startup limit is set to a total load rate of 20%. The conditions for stopping the operation of the power channel transmission device are:

[0060] 1. The load rate of all stations is lower than β-10%;

[0061] 2. There are areas where the load rate is greater than βweight-10% and less than βweight, and the load rate difference between each area (βmax-βmin) is less than 20%.

[0062] 3. The load rate of some substations exceeds β, and the load rate deviation of each substation (βmax-βmin) is less than 10%.

[0063] The load factor refers to the ratio of the load power in the substation (including the power provided by the transformer and the power provided by the mutual aid equipment) to the transformer capacity.

[0064] The power channel transmission device starts working when any of the following conditions are met:

[0065] 1. When the load rate of a certain area exceeds β weight and the load rate difference (βmax-βmin) exceeds 10%, or the load rate of the area is greater than β weight-10% and less than β weight, and the load rate difference exceeds 20%;

[0066] 2. The dispatching target is that the difference in load rates between the two transformers is less than 5%. The principle is to provide energy from the lowest load rate to the highest load rate.

[0067] 3. When the capacity to be dispatched exceeds the capacity of the device, the device outputs according to its maximum capacity.

[0068] 4. When the load rate of all substations is lower than β-weight-15%, the equipment will exit mutual assistance.

[0069] Through such an arrangement, the present invention is used for 3 months in the summer in the Jiangmashanbei area, meeting the needs of small workshops and commercial use.

[0070] In the description of this specification, the description with reference to the terms "one embodiment / method", "some embodiments / methods", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment / method or example are included in at least one embodiment / method or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment / method or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments / methods or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments / methods or examples described in this specification and the features of the different embodiments / methods or examples, unless they are contradictory.

[0071] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0072] Those skilled in the art should understand that the above embodiments are only for the purpose of clearly illustrating the present disclosure, and are not intended to limit the scope of the present disclosure. For those skilled in the art, other changes or modifications may be made based on the above disclosure, and these changes or modifications are still within the scope of the present disclosure.

Claims

1. A mobile electric energy channel transmission device, characterized in that: The invention comprises a box body, wherein at least two DC conversion units are arranged in the box body, each DC conversion unit has the same structure and comprises a power conversion unit, the DC ends of the power conversion units in each DC conversion power supply are reversely connected to each other so as to realize the conversion between AC / DC and DC / AC, the AC ends of each power conversion unit are respectively connected to different substations, each power conversion unit is respectively connected to a main controller, and a plurality of main controllers are connected to each other, and the other end of the main controller is connected to a fusion terminal through a collector, wherein two main controllers are connected to each other through 485 / CAN communication to realize the substation power scheduling by themselves; the main controller communicates with the fusion terminal or concentrator through carrier or micro-power wireless using 645 protocol, after the main controller collects the total meter current through the fusion terminal or concentrator, the total meter current data is sent to the device after the specified time through the carrier / micro-power wireless interval, and the mutual assistance device determines whether it is necessary to start mutual assistance by itself, starts working when the mutual assistance conditions are met, and stops working when the shutdown conditions are met.

2. A mobile power channel transmission device as claimed in claim 1, characterized in that: The AC end of the power conversion unit is connected to the station area through an AC circuit breaker.

3. A mobile power channel transmission device as claimed in claim 2, characterized in that: A bidirectional electric meter is also arranged between the power conversion unit and the AC circuit breaker, and the external AC power is converted into DC power through the bidirectional electric meter to the power conversion unit.

4. A mobile power channel transmission device as claimed in claim 1, characterized in that: The box is installed between multiple transformers in a power distribution room or between branches at the end of a transformer area.

5. The mobile power channel transmission device according to claim 1, characterized in that: The outlet of the box has a separate junction box with a plug-and-play socket, and the low-voltage cable is connected at the junction box.

6. A mobile power channel transmission device according to claim 1, wherein the two DC conversion units are connected to the first station area and the second station area respectively, characterized in that: The starting conditions for the power channel transmission device to start working are: When the load factor of any area exceeds β weight and the load factor difference exceeds the first start limit, or the load factor of the area is greater than the difference between β weight and the first start limit and less than β weight, or the load factor difference exceeds the second start limit.

7. A mobile power channel transmission device as claimed in claim 6, characterized in that: The dispatching target after startup is that the difference in load rates of the two transformers is less than 5%, providing energy at the lowest load rate to the highest load rate; when the capacity to be dispatched exceeds the capacity of the equipment, the equipment outputs according to its maximum capacity.

8. A mobile power channel transmission device as claimed in claim 7, characterized in that: The conditions for the power channel transmission device to stop working include: the load rate of all substations is lower than β weight minus the first starting limit; or at least one substation has a load rate greater than β weight minus the first starting limit and less than β weight; or the difference between the load rates of each substation is less than the second starting limit; or the load rate of one substation exceeds β weight, and the deviation of the load rates of each substation is less than the first starting limit.

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