Power distribution network interconnection system control method based on intelligent soft switch and related equipment

Abstract

The embodiment of the invention discloses a power distribution network interconnection system control method based on an intelligent soft switch and related equipment, and the method comprises the steps: obtaining three phases of to-be-compensated currents of a transformer area, and sequentially sorting the three phases of to-be-compensated currents to obtain a maximum-phase to-be-compensated current, an intermediate-phase to-be-compensated current and a minimum-phase to-be-compensated current, under the condition that the maximum-phase to-be-compensated current is greater than the rated current, determining the mobile-phase to-be-compensated current according to the maximum-phase to-be-compensated current, the rated current and the alternating current of the distributed power supply, and controlling the first fixed intelligent soft switch to output the rated current to the maximum-phase feeder line of the transformer area, controlling the motorized intelligent soft switch to output motorized phase current to be compensated to the maximum phase feeder line of the transformer area, controlling the second fixed intelligent soft switch to output intermediate phase current to be compensated to the intermediate phase feeder line of the transformer area, and controlling the third fixed intelligent soft switch to output minimum phase current to be compensated to the minimum phase feeder line of the transformer area; therefore, the light and heavy load problems and the three-phase imbalance problem of the transformer in the transformer area are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of power systems, and in particular to a distribution network interconnection system control method based on intelligent soft switches and related equipment. Background Art

[0002] With the massive access of distributed generation (DG) and random loads in the distribution network, especially in the low-voltage distribution substations with complex network structures and user types, the interweaving and disorderly access of single-phase / three-phase loads have made the problems of light and heavy loads and three-phase imbalance of transformers in the substations increasingly prominent, threatening the safe and reliable operation of the substations.

[0003] At present, there is an urgent need for a solution to solve the problems of light and heavy loads and three-phase imbalance of transformers in the substation area. Summary of the invention

[0004] Based on this, it is necessary to propose a distribution network interconnection system control method and related equipment based on intelligent soft switches to address the above problems, so as to solve the transformer light and heavy load problems and three-phase imbalance problems in the substation area.

[0005] To achieve the above object, the present invention provides, in a first aspect, a control method for a distribution network interconnection system based on an intelligent soft switch, the method comprising:

[0006] Acquire three-phase currents to be compensated in the substation, and sort the three-phase currents to be compensated in order from high to low to obtain a maximum current to be compensated, an intermediate current to be compensated, and a minimum current to be compensated;

[0007] In the case where the maximum phase-to-phase compensation current is greater than the rated current of the first fixed intelligent soft switch, determining the mobile phase-to-phase compensation current according to the maximum phase-to-phase compensation current, the rated current and the AC current of the distributed power source;

[0008] Control the first fixed intelligent soft switch to output the rated current to the maximum phase feeder of the substation, control the mobile intelligent soft switch to output the mobile phase compensation current to the maximum phase feeder of the substation, control the second fixed intelligent soft switch to output the middle phase compensation current to the middle phase feeder of the substation, and control the third fixed intelligent soft switch to output the minimum phase compensation current to the minimum phase feeder of the substation;

[0009] Among them, the maximum phase feeder is the feeder of the phase corresponding to the maximum phase current to be compensated, the middle phase feeder is the feeder of the phase corresponding to the middle phase current to be compensated, the minimum phase feeder is the feeder of the phase corresponding to the minimum phase current to be compensated, and the substation includes a first interconnected substation and a second interconnected substation.

[0010] Optionally, the obtaining of the three-phase current to be compensated in the transformer area includes:

[0011] Obtaining the three-phase negative-sequence current to be compensated, the three-phase zero-sequence current to be compensated and the three-phase load current to be compensated of the first interconnected substation, and the three-phase negative-sequence current to be compensated, the three-phase zero-sequence current to be compensated and the load current required for three-phase voltage stabilization of the second interconnected substation;

[0012] The three-phase current to be compensated in the first interconnected substation is determined according to the three-phase negative-sequence current to be compensated, the three-phase zero-sequence current to be compensated and the three-phase load current to be compensated in the first interconnected substation, and the three-phase current to be compensated in the second interconnected substation is determined according to the three-phase negative-sequence current to be compensated, the three-phase zero-sequence current to be compensated and the load current required for three-phase voltage stability in the second interconnected substation.

[0013] Optionally, the obtaining of the three-phase negative-sequence current to be compensated, the three-phase zero-sequence current to be compensated and the three-phase load current to be compensated of the first interconnected substation, and the three-phase negative-sequence current to be compensated, the three-phase zero-sequence current to be compensated and the load current required for three-phase voltage stabilization of the second interconnected substation includes:

[0014] Acquire the three-phase current of the first interconnected substation and the three-phase current of the second interconnected substation, and the power to be transmitted between the first interconnected substation and the second interconnected substation, wherein the power to be transmitted is the power that the first interconnected substation needs to transmit to the second interconnected substation when the load rate of the first interconnected substation is equal to the load rate of the second interconnected substation;

[0015] Decomposing the three-phase current of the first interconnected substation by sequence components to obtain the three-phase negative-sequence current to be compensated and the three-phase zero-sequence current to be compensated of the first interconnected substation, and decomposing the three-phase current of the second interconnected substation by sequence components to obtain the three-phase negative-sequence current to be compensated and the three-phase zero-sequence current to be compensated of the second interconnected substation;

[0016] The three-phase load current to be compensated in the first interconnected area and the three-phase load current required for voltage stabilization in the second interconnected area are determined according to the power to be transmitted.

[0017] Optionally, the method of determining the three-phase current to be compensated in the first interconnected substation according to the three-phase negative-sequence current to be compensated, the three-phase zero-sequence current to be compensated and the three-phase load current to be compensated of the first interconnected substation, and determining the three-phase current to be compensated in the second interconnected substation according to the three-phase negative-sequence current to be compensated, the three-phase zero-sequence current to be compensated and the load current required for three-phase voltage stabilization of the second interconnected substation includes:

[0018] Using the formula Determine the three-phase current to be compensated in the first interconnected area, and use the formula Determining the three-phase current to be compensated in the second interconnected substation;

[0019] Among them, I l1_ref,1 ,I l1_ref,2 and I l1_ref,3 are respectively a first phase current to be compensated, a second phase current to be compensated and a third phase current to be compensated among the three phase currents to be compensated in the first interconnected substation, and are respectively a first phase load current to be compensated, a second phase load current to be compensated and a third phase load current to be compensated among the three-phase load currents to be compensated in the first interconnected substation, and are respectively the first phase negative sequence current to be compensated, the second phase negative sequence current to be compensated and the third phase negative sequence current to be compensated of the three-phase negative sequence current to be compensated in the first interconnected substation, and are respectively the first phase zero-sequence current to be compensated, the second phase zero-sequence current to be compensated and the third phase zero-sequence current to be compensated in the three-phase zero-sequence current to be compensated in the first interconnected substation, I l2_ref,1 ,I l2_ref,2 and I l2_ref,3 are respectively a first phase current to be compensated, a second phase current to be compensated and a third phase current to be compensated among the three phase currents to be compensated in the second interconnected substation, and are respectively a first phase load current to be compensated, a second phase load current to be compensated and a third phase load current to be compensated among the three-phase load current to be compensated of the second interconnected substation, and are respectively the first phase negative sequence current to be compensated, the second phase negative sequence current to be compensated and the third phase negative sequence current to be compensated among the three-phase negative sequence current to be compensated in the second interconnected substation, and They are respectively the first phase zero-sequence current to be compensated, the second phase zero-sequence current to be compensated and the third phase zero-sequence current to be compensated among the three-phase zero-sequence current to be compensated in the second interconnected substation.

[0020] Optionally, determining the motorized phase compensation current according to the maximum phase compensation current, the rated current and the AC current of the distributed power source includes:

[0021] Using the formula Determining the motor phase compensation current;

[0022] in, is the motor phase compensation current, I l1orl2_ref,1or2or3 is the maximum phase compensation current, I N is the rated current, I DG is the AC current of the distributed power source.

[0023] To achieve the above-mentioned object, the present invention provides, in a second aspect, a distribution network interconnection system based on an intelligent soft switch, the system comprising a management device including an intelligent soft switch and a controller, the management device including an intelligent soft switch comprising a first fixed intelligent soft switch, a second fixed intelligent soft switch, a third fixed intelligent soft switch and a mobile intelligent soft switch;

[0024] The controller is connected to the first fixed intelligent soft switch, the second fixed intelligent soft switch, the third fixed intelligent soft switch, and the mobile intelligent soft switch respectively; the first fixed intelligent soft switch is connected to the maximum phase feeder of the substation; the second fixed intelligent soft switch is connected to the middle phase feeder of the substation; the third fixed intelligent soft switch is connected to the minimum phase feeder of the substation; and the mobile intelligent soft switch is connected to the maximum phase feeder and the distributed power source of the substation respectively;

[0025] The controller is used to execute the method as described in any one of the first aspects;

[0026] Among them, the maximum phase feeder is the feeder of the phase corresponding to the maximum phase current to be compensated, the middle phase feeder is the feeder of the phase corresponding to the middle phase current to be compensated, the minimum phase feeder is the feeder of the phase corresponding to the minimum phase current to be compensated, and the substation includes a first interconnected substation and a second interconnected substation.

[0027] Optionally, the management device including the intelligent soft switch further includes a first multi-way switch, a second multi-way switch, a third multi-way switch, a fourth multi-way switch, a fifth multi-way switch, a sixth multi-way switch, a seventh multi-way switch and an eighth multi-way switch;

[0028] The first to the eighth multi-way switches are all connected to the controller, the first fixed intelligent soft switch is connected to the maximum phase feeder, the middle phase feeder and the minimum phase feeder of the first interconnected substation through the first multi-way switch, the second fixed intelligent soft switch is connected to the maximum phase feeder, the middle phase feeder and the minimum phase feeder of the first interconnected substation through the second multi-way switch, the third fixed intelligent soft switch is connected to the maximum phase feeder, the middle phase feeder and the minimum phase feeder of the first interconnected substation through the third multi-way switch, the mobile intelligent soft switch is connected to the maximum phase feeder, the middle phase feeder and the minimum phase feeder of the first interconnected substation through the third multi-way switch, The first fixed intelligent soft switch is connected to the maximum phase feeder line, the middle phase feeder line and the minimum phase feeder line of the second interconnected substation through the fourth multi-way switch, the first fixed intelligent soft switch is connected to the maximum phase feeder line, the middle phase feeder line and the minimum phase feeder line of the second interconnected substation through the fifth multi-way switch, the second fixed intelligent soft switch is connected to the maximum phase feeder line, the middle phase feeder line and the minimum phase feeder line of the second interconnected substation through the sixth multi-way switch, the third fixed intelligent soft switch is connected to the maximum phase feeder line, the middle phase feeder line and the minimum phase feeder line of the second interconnected substation through the seventh multi-way switch, and the mobile intelligent soft switch is connected to the maximum phase feeder line, the middle phase feeder line and the minimum phase feeder line of the second interconnected substation through the eighth multi-way switch;

[0029] The controller is further used to control the first to eighth multi-way switches to respectively switch on one of the maximum phase feeder, the middle phase feeder and the minimum phase feeder and cut off the remaining two feeders.

[0030] Optionally, the first fixed intelligent soft switch, the second fixed intelligent soft switch, the third fixed intelligent soft switch and the mobile intelligent soft switch are all composed of back-to-back single-phase full-bridge converters.

[0031] To achieve the above object, the present invention provides, in a third aspect, a control device for a distribution network interconnection system based on an intelligent soft switch, the device comprising:

[0032] An acquisition and sorting module, used for acquiring the three-phase currents to be compensated in the substation, and sorting the three-phase currents to be compensated in order from high to low to obtain the maximum current to be compensated, the middle current to be compensated and the minimum current to be compensated;

[0033] A judgment and determination module, configured to determine the mobile phase compensation current according to the maximum phase compensation current, the rated current and the AC current of the distributed power source when the maximum phase compensation current is greater than the rated current of the first fixed intelligent soft switch;

[0034] A control module, configured to control the first fixed intelligent soft switch to output the rated current to the maximum phase feeder of the substation, control the mobile intelligent soft switch to output the mobile phase compensation current to the maximum phase feeder of the substation, control the second fixed intelligent soft switch to output the second phase compensation current to the middle phase feeder of the substation, and control the third fixed intelligent soft switch to output the phase compensation current to the minimum phase feeder of the substation;

[0035] Among them, the maximum phase feeder is the feeder of the phase corresponding to the maximum phase current to be compensated, the middle phase feeder is the feeder of the phase corresponding to the middle phase current to be compensated, the minimum phase feeder is the feeder of the phase corresponding to the minimum phase current to be compensated, and the substation includes a first interconnected substation and a second interconnected substation.

[0036] To achieve the above-mentioned objective, the present invention provides in a fourth aspect a computer-readable storage medium storing a computer program, wherein when the computer program is executed by a processor, the processor executes a method as described in any one of the first aspects.

[0037] To achieve the above-mentioned purpose, the present invention provides a computer device in a fifth aspect, comprising a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the method as described in any one of the first aspects.

[0038] The embodiment of the present invention has the following beneficial effects: the above method obtains the three-phase current to be compensated in the substation, and sorts the three-phase current to be compensated in order from high to low to obtain the maximum phase compensation current, the middle phase compensation current and the minimum phase compensation current. When the maximum phase compensation current is greater than the rated current of the first fixed intelligent soft switch, the mobile phase compensation current is determined according to the maximum phase compensation current, the rated current and the AC current of the distributed power source, and the first fixed intelligent soft switch is controlled to output the rated current to the maximum phase feeder of the substation, and the mobile intelligent soft switch is controlled to output the rated current to the maximum phase feeder of the substation. The large phase feeder outputs a mobile phase compensation current, and controls the second fixed intelligent soft switch to output the middle phase compensation current to the middle phase feeder of the substation, and controls the third fixed intelligent soft switch to output the minimum phase compensation current to the minimum phase feeder of the substation, wherein the maximum phase feeder is the feeder of the phase corresponding to the maximum phase compensation current, the middle phase feeder is the feeder of the phase corresponding to the middle phase compensation current, and the minimum phase feeder is the feeder of the phase corresponding to the minimum phase compensation current, and the substation includes a first interconnected substation and a second interconnected substation; that is, it realizes the control of the light and heavy load problems and three-phase imbalance problems of the transformer in the substation. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0040] in:

[0041] Figure 1 Schematic diagram of a control method for a distribution network interconnection system based on an intelligent soft switch in an embodiment of the present application;

[0042] Figure 2 A schematic diagram of a power distribution network interconnection system based on an intelligent soft switch in an embodiment of the present application;

[0043] Figure 3 A schematic diagram of the waveforms of the three-phase currents of the first interconnected substation under various working conditions under simulation in an embodiment of the present application;

[0044] Figure 4 A schematic diagram of the waveforms of the three-phase currents of the second interconnected substation under various working conditions under simulation in an embodiment of the present application;

[0045] Figure 5 A schematic diagram of a tracking signal of a transmission compensation current of an MSOP under simulation conditions in an embodiment of the present application;

[0046] Figure 6 A schematic diagram of a control device for a power distribution network interconnection system based on an intelligent soft switch in an embodiment of the present application;

[0047] Figure 7 1 is a diagram of the internal structure of a computer device in some embodiments. DETAILED DESCRIPTION

[0048] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0049] With the massive access of distributed generation (DG) and random loads in the distribution network, especially in low-voltage distribution substations with complex network structures and user types, the interweaving and disorderly access of single-phase / three-phase loads have made the problems of light and heavy loads and three-phase imbalance of transformers in the substations increasingly prominent, threatening the safe and reliable operation of the substations.

[0050] At present, there is an urgent need for a solution to solve the problems of light and heavy loads and three-phase imbalance of transformers in the substation area.

[0051] Prior to this application, studies have been conducted on solutions to address the problems of light and heavy loads and three-phase imbalance in transformers in substations. However, compared with the distribution network interconnection system control method and related equipment based on intelligent soft switches proposed in this application, there are still certain problems.

[0052] The research before this application can only deal with the three-phase imbalance problem in the substation, and cannot deal with the transformer light or heavy load problem and the three-phase imbalance problem in the substation at the same time. In terms of dealing with the three-phase imbalance problem in the substation, it mainly relies on equipment such as switching capacitors, static VAR compensators and phase converters; among them, switching capacitors is the most common way to compensate for the three-phase unbalanced load of the substation, but the action time is long, and the continuous adjustment of reactive power cannot be achieved, and there is a transient impact when the capacitor is switched; although the static VAR compensator can continuously adjust the reactive power, it still cannot compensate for the active power; the phase converter can control the active power and reactive power at the same time, but a large amount of investment is required to achieve the three-phase imbalance control effect, the cost is high, and the equipment utilization rate is low; therefore, the research before this application has problems such as single function, high investment cost, slow action response, etc. in dealing with the three-phase imbalance problem in the substation, and it is impossible to take into account the mutual assistance between different substations and the control of the transformer light or heavy load problem.

[0053] Of course, the research conducted before this application can also simultaneously deal with the transformer light and heavy load problems and three-phase imbalance problems in the substation, that is, by utilizing a variety of flexible interconnection series concepts such as ring network power controllers, balancers, and intelligent power routers, the transformer light and heavy load and three-phase imbalance problems in the substation are integrated and managed to improve the utilization rate of the management system and the comprehensive management effect; but since the management system adopts a fixed capacity configuration, it is necessary to reasonably configure the fixed capacity in combination with the maximum power required for three-phase imbalance management at rated input / output power, and when the three-phase imbalance is large, the system will have a large idle capacity, resulting in relatively high hardware costs; in addition, the large-scale access of random loads has led to increasingly serious single-phase heavy overload problems, making it difficult to flexibly regulate power in phases.

[0054] In response to the above problems, the present application proposes a distribution network interconnection system control method and related equipment based on intelligent soft switches, which realizes the management of transformer light and heavy load problems and three-phase imbalance problems in the substation area; in addition, the present application has flexible phase-by-phase regulation capabilities, which solves the technical problems existing in the previous research of the present application, and also realizes efficient and comprehensive management of transformer light and heavy loads, three-phase imbalance and single-phase heavy overload problems in the substation area under the condition of low overall capacity, which significantly improves the interconnection and high-quality distribution capabilities of the distribution network, while reducing the configuration cost of the management system, and has important engineering application value. The specific implementation principles will be described in detail in the following embodiments.

[0055] In a first aspect, the present application provides a distribution network interconnection system control method based on intelligent soft switches.

[0056] See also Figure 1 , is a schematic diagram of a distribution network interconnection system control method based on an intelligent soft switch in an embodiment of the present application, the method comprising:

[0057] Step 110: obtaining the three-phase currents to be compensated in the transformer substation, and sorting the three-phase currents to be compensated in order from high to low to obtain the maximum current to be compensated, the middle current to be compensated, and the minimum current to be compensated.

[0058] Among them, the substation refers to the substation of the distribution network, that is, an area of ​​power supply; the three-phase current to be compensated refers to the current to be compensated of the three phases A, B and C (that is, U, V and W), and the current to be compensated refers to the current that needs to be compensated due to various factors, for example, the current that needs to be compensated caused by the large number of distributed power sources and random loads connected to the substation.

[0059] Step 120: When the maximum phase compensation current is greater than the rated current of the first fixed intelligent soft switch, the mobile phase compensation current is determined according to the maximum phase compensation current, the rated current and the AC current of the distributed power source.

[0060] Among them, distributed power sources refer to renewable energy, such as solar energy, wind energy and other renewable energy sources.

[0061] It should be noted that when the maximum phase compensation current exceeds the rated current of the first fixed intelligent soft switch used, it means that the first fixed intelligent soft switch alone cannot fully compensate the phase corresponding to the maximum phase compensation current. Then it is necessary to determine an additional mobile phase compensation current to make up for the difference. Therefore, it is necessary to comprehensively consider the maximum phase compensation current, the rated current of the first intelligent soft switch and the AC current of the distributed power source to determine the mobile phase compensation current; it is understandable that the access of distributed power sources will affect the current distribution in the substation, so its impact needs to be considered.

[0062] Step 130: Control the first fixed intelligent soft switch to output the rated current to the maximum phase feeder of the substation, and control the mobile intelligent soft switch to output the mobile phase compensation current to the maximum phase feeder of the substation, and control the second fixed intelligent soft switch to output the intermediate phase compensation current to the intermediate phase feeder of the substation, and control the third fixed intelligent soft switch to output the minimum phase compensation current to the minimum phase feeder of the substation.

[0063] It should be noted that in the present application, since the intermediate phase compensation current usually does not exceed the rated current of the second fixed intelligent soft switch used, and the minimum phase compensation current usually does not exceed the rated current of the third fixed intelligent soft switch used, the present application assumes that the intermediate phase compensation current is less than the rated current of the second fixed intelligent soft switch, and the minimum phase compensation current is less than the rated current of the third fixed intelligent soft switch.

[0064] In some embodiments, the rated currents of the first fixed intelligent soft switch, the second fixed intelligent soft switch, and the third fixed intelligent soft switch used in the present application decrease in sequence (i.e., the capacity decreases in sequence), that is, the rated power of the first fixed intelligent soft switch is less than the rated power of the second fixed intelligent soft switch, and the rated power of the second fixed intelligent soft switch is less than the rated power of the third fixed intelligent soft switch.

[0065] It should be noted in particular that, when the maximum phase-to-phase compensation current is greater than the rated current of the first fixed intelligent soft switch, the first fixed intelligent soft switch alone cannot fully compensate the phase corresponding to the maximum phase-to-phase compensation current. Therefore, a mobile intelligent soft switch is used to output an additional mobile phase-to-phase compensation current to share the maximum phase-to-phase compensation current to achieve full compensation. When the maximum phase-to-phase compensation current is less than or equal to the rated current of the first fixed intelligent soft switch, the first fixed intelligent soft switch can fully compensate the phase corresponding to the maximum phase-to-phase compensation current. Therefore, the use of a mobile intelligent soft switch can also directly send the power generated by the distributed power source to the feeder to consume the feeder load locally.

[0066] In the present application, the maximum phase feeder is the feeder corresponding to the phase with the maximum phase-to-be-compensated current, the middle phase feeder is the feeder corresponding to the phase with the middle phase-to-be-compensated current, the minimum phase feeder is the feeder corresponding to the phase with the minimum phase-to-be-compensated current, and the substation includes a first interconnected substation and a second interconnected substation, that is, the first interconnected substation and the second interconnected substation are interconnected.

[0067] For the first interconnected substation, the three-phase currents to be compensated of the first interconnected substation are obtained, and the three-phase currents to be compensated are sorted in order from high to low to obtain the maximum phase compensation current, the middle phase compensation current and the minimum phase compensation current; when the maximum phase compensation current is greater than the rated current of the first fixed intelligent soft switch, the mobile phase compensation current is determined according to the maximum phase compensation current, the rated current and the AC current of the distributed power source; the first fixed intelligent soft switch is controlled to output the rated current to the maximum phase feeder of the first interconnected substation, and the mobile intelligent soft switch is controlled to output the mobile phase compensation current to the maximum phase feeder of the first interconnected substation, and the second fixed intelligent soft switch is controlled to output the middle phase compensation current to the middle phase feeder of the first interconnected substation, and the third fixed intelligent soft switch is controlled to output the minimum phase compensation current to the minimum phase feeder of the first interconnected substation.

[0068] For the second interconnected substation, the three-phase current to be compensated of the second interconnected substation is obtained, and the three-phase current to be compensated is sorted from high to low to obtain the maximum phase compensation current, the middle phase compensation current and the minimum phase compensation current; when the maximum phase compensation current is greater than the rated current of the first fixed intelligent soft switch, the mobile phase compensation current is determined according to the maximum phase compensation current, the rated current and the AC current of the distributed power source; the first fixed intelligent soft switch is controlled to output the rated current to the maximum phase feeder of the second interconnected substation, and the mobile intelligent soft switch is controlled to output the mobile phase compensation current to the maximum phase feeder of the second interconnected substation, and the second fixed intelligent soft switch is controlled to output the middle phase compensation current to the middle phase feeder of the second interconnected substation, and the third fixed intelligent soft switch is controlled to output the minimum phase compensation current to the minimum phase feeder of the second interconnected substation.

[0069] It should also be specially explained that, since the present application is real-time in comprehensively managing the problems of light and heavy loads, three-phase imbalance and single-phase heavy overloads of transformers in the substation area, for step 110, the maximum phase compensation current, the middle phase compensation current and the minimum phase compensation current obtained at the current moment need to be compared with the maximum phase compensation current, the middle phase compensation current and the minimum phase compensation current obtained at the previous moment. If there is no change after the comparison, there is no need to execute steps 120 to 130, that is, control is performed according to the original state. If there is a change after the comparison, steps 120 to 130 need to be executed to control according to the new state.

[0070] In an embodiment of the present application, by obtaining the three-phase compensation current of the substation and sorting them in sequence to obtain the maximum compensation current, the middle compensation current and the minimum compensation current, when the maximum compensation current is greater than the rated current, the mobile compensation current is determined according to the maximum compensation current, the rated current and the AC current of the distributed power source, the first fixed intelligent soft switch is controlled to output the rated current to the maximum phase feeder of the substation, and the mobile intelligent soft switch is controlled to output the mobile compensation current to the maximum phase feeder of the substation, and the second fixed intelligent soft switch is controlled to output the middle compensation current to the middle phase feeder of the substation, and the third fixed intelligent soft switch is controlled to output the minimum compensation current to the minimum phase feeder of the substation, the substation includes a first interconnected substation and a second interconnected substation; that is, the light and heavy load problems and three-phase imbalance problems of the transformer in the substation are solved.

[0071] In addition, the present application has flexible phase-by-phase control capabilities, which solves the technical problems existing in the previous research of the present application. It also achieves efficient and comprehensive management of problems such as light and heavy loads, three-phase imbalance and single-phase heavy overloads of transformers in the substation area under low overall capacity. It significantly improves the interconnection and high-quality distribution capabilities of the distribution network, while reducing the configuration cost of the management system, and has important engineering application value.

[0072] In a feasible implementation, step 110 in the above embodiment, obtaining the three-phase current to be compensated in the substation, includes: obtaining the three-phase negative-sequence current to be compensated, the three-phase zero-sequence current to be compensated and the three-phase load current to be compensated of the first interconnected substation, and the three-phase negative-sequence current to be compensated, the three-phase zero-sequence current to be compensated and the load current required for three-phase voltage regulation of the second interconnected substation; determining the three-phase current to be compensated in the first interconnected substation according to the three-phase negative-sequence current to be compensated, the three-phase zero-sequence current to be compensated and the three-phase load current to be compensated of the first interconnected substation, and determining the three-phase current to be compensated in the second interconnected substation according to the three-phase negative-sequence current to be compensated, the three-phase zero-sequence current to be compensated and the load current required for three-phase voltage regulation of the second interconnected substation.

[0073] Among them, the three-phase negative-sequence current to be compensated refers to the negative-sequence current to be compensated of the three phases A, B and C (i.e., U, V and W), and the negative-sequence current to be compensated refers to the current that needs to be compensated due to asymmetric load or system failure; the three-phase zero-sequence current to be compensated refers to the zero-sequence current to be compensated of the three phases A, B and C (i.e., U, V and W), and the zero-sequence current to be compensated refers to the current that needs to be compensated due to uneven load, capacitive coupling, transformer grounding method and system failure; the three-phase The compensated load current refers to the load current to be compensated of the three phases A, B and C (i.e. U, V and W). The load current to be compensated refers to the current that needs to be compensated due to the imbalance of the three-phase load current due to various reasons (such as load changes, equipment aging, three-phase imbalance, etc.); the load current required for three-phase voltage stabilization refers to the load current required for voltage stabilization of the three phases A, B and C (i.e. U, V and W). The load current required for voltage stabilization refers to the current required to ensure the stability of the output voltage and the normal operation of the equipment.

[0074] In an embodiment of the present application, by obtaining the three-phase negative-sequence current to be compensated, the three-phase zero-sequence current to be compensated and the three-phase load current to be compensated of the first interconnected substation, as well as the three-phase negative-sequence current to be compensated, the three-phase zero-sequence current to be compensated and the load current required for three-phase voltage regulation of the second interconnected substation, the three-phase current to be compensated of the first interconnected substation and the three-phase current to be compensated of the second interconnected substation are obtained, and the three-phase current to be compensated required by the first interconnected substation and the second interconnected substation can be accurately determined, which helps to improve the overall performance and stability of the power system, ensure the normal operation of equipment and systems, and provide reliable power guarantee for people's lives and industrial production.

[0075] In a feasible implementation, the obtaining of the three-phase negative-sequence current to be compensated, the three-phase zero-sequence current to be compensated and the three-phase load current to be compensated of the first interconnected substation, as well as the three-phase negative-sequence current to be compensated, the three-phase zero-sequence current to be compensated and the load current required for three-phase voltage stabilization of the second interconnected substation in the above embodiment includes: obtaining the three-phase current of the first interconnected substation and the three-phase current of the second interconnected substation, and the power to be transmitted between the first interconnected substation and the second interconnected substation, wherein the power to be transmitted is the power that the first interconnected substation needs to transmit to the second interconnected substation when the load rate of the first interconnected substation is equal to the load rate of the second interconnected substation; performing sequence component decomposition on the three-phase current of the first interconnected substation to obtain the three-phase negative-sequence current to be compensated and the three-phase zero-sequence current to be compensated of the first interconnected substation, and performing sequence component decomposition on the three-phase current of the second interconnected substation to obtain the three-phase negative-sequence current to be compensated and the three-phase zero-sequence current to be compensated of the second interconnected substation; and determining the three-phase load current to be compensated of the first interconnected substation and the load current required for three-phase voltage stabilization of the second interconnected substation according to the power to be transmitted.

[0076] The three-phase current refers to the current measured for the three phases of A phase, B phase and C phase (ie, U phase, V phase and W phase).

[0077] In some embodiments, the three-phase current of the first interconnected area and the three-phase current of the second interconnected area, as well as the power that needs to be transmitted from the first interconnected area to the second interconnected area when the load rate of the first interconnected area is equal to the load rate of the second interconnected area (i.e., the power to be transmitted) can be obtained from the metering automation system through a data acquisition device.

[0078] In an embodiment of the present application, by obtaining the three-phase current of the first interconnected substation and the second interconnected substation, and the power to be transmitted therebetween, and then decomposing the respective three-phase negative-sequence current to be compensated and the three-phase zero-sequence current to be compensated, and determining the corresponding load current according to the power to be transmitted, it is possible to accurately compensate for the unbalanced current, optimize power transmission, reduce energy consumption, improve energy efficiency, and enhance system stability, thereby providing strong support for the stable operation and efficient power supply of the power system.

[0079] It can be understood that by decomposing the sequence components, the negative sequence current and zero sequence current of each interconnected area can be accurately obtained, which is a key step to achieve three-phase current balance. If the negative sequence and zero sequence currents are not compensated, it will cause equipment overheating, reduced efficiency or even damage. By compensating these unbalanced currents, the stability of the power system and the service life of the equipment can be significantly improved; according to the power to be transmitted between the first interconnected area and the second interconnected area, the amount of electricity to be transmitted can be determined, so as to achieve load balancing between the two interconnected areas, which helps to avoid the situation where some areas are overloaded while other areas are lightly loaded, and improve the operating efficiency of the entire power system; by compensating for unbalanced currents and optimizing power transmission, line losses can be reduced and power utilization can be improved. This can not only reduce energy waste, but also save operating costs; the three-phase current after compensation is more balanced, which helps to reduce voltage fluctuations and flicker, and improve the stability of the power system, which is of great significance for ensuring power supply quality and meeting user needs.

[0080] In a feasible implementation, the above embodiment determines the three-phase current to be compensated in the first interconnected area according to the three-phase negative-sequence current to be compensated, the three-phase zero-sequence current to be compensated and the three-phase load current to be compensated of the first interconnected area, and determines the three-phase current to be compensated in the second interconnected area according to the three-phase negative-sequence current to be compensated, the three-phase zero-sequence current to be compensated and the load current required for three-phase voltage stabilization of the second interconnected area, including:

[0081] Using the formula Determine the three-phase current to be compensated in the first interconnected area, and use the formula Determine the three-phase current to be compensated in the second interconnected substation;

[0082] Among them, Il1_ref,1 ,I l1_ref,2 and I l1_ref,3 are respectively the first phase current to be compensated, the second phase current to be compensated and the third phase current to be compensated of the three-phase current to be compensated in the first interconnected substation, and are respectively the first phase load current to be compensated, the second phase load current to be compensated and the third phase load current to be compensated among the three-phase load current to be compensated in the first interconnected substation, and are respectively the first phase negative sequence current to be compensated, the second phase negative sequence current to be compensated and the third phase negative sequence current to be compensated of the three-phase negative sequence current to be compensated in the first interconnected substation, and are the first phase zero-sequence current to be compensated, the second phase zero-sequence current to be compensated and the third phase zero-sequence current to be compensated in the three-phase zero-sequence current to be compensated in the first interconnected substation, I l2_ref,1 ,I l2_ref,2 and I l2_ref,3 are respectively the first phase current to be compensated, the second phase current to be compensated and the third phase current to be compensated of the three-phase current to be compensated in the second interconnected station area, and are respectively the first phase load current to be compensated, the second phase load current to be compensated and the third phase load current to be compensated among the three-phase load current to be compensated in the second interconnected substation, and are respectively the first phase negative sequence current to be compensated, the second phase negative sequence current to be compensated and the third phase negative sequence current to be compensated in the three-phase negative sequence current to be compensated in the second interconnected substation, and They are respectively the first phase zero-sequence current to be compensated, the second phase zero-sequence current to be compensated and the third phase zero-sequence current to be compensated of the three-phase zero-sequence current to be compensated in the second interconnected substation.

[0083] In the present application, the first phase, the second phase, and the third phase refer to the A phase, the B phase, and the C phase (ie, the U phase, the V phase, and the W phase).

[0084] In the embodiments of the present application, a rigorous calculation formula for the three-phase current to be compensated is provided from a mathematical perspective. The accuracy of the calculated three-phase current to be compensated can be ensured from the rigor of mathematical logic, and the above calculation formula is preferably shown to provide reference, understanding and calculation for technical personnel; in addition, by adopting the above calculation formula to calculate the three-phase current to be compensated, it is possible to accurately compensate for unbalanced current, optimize power transmission, reduce energy consumption, improve energy efficiency and enhance system stability, thereby providing strong support for the stable operation and efficient power supply of the power system.

[0085] In a feasible implementation, the method of determining the motorized phase compensation current according to the maximum phase compensation current, the rated current and the AC current of the distributed power source in the above embodiment includes:

[0086] Using the formula Determine the motor phase compensation current;

[0087] in, is the motor phase compensation current, I l1orl2_ref,1or2or3 is the maximum phase compensation current, I N is the rated current, I DG is the AC current of the distributed power source.

[0088] In the embodiments of the present application, a rigorous calculation formula for the mobile phase compensation current is provided from a mathematical perspective. The accuracy of the calculated mobile phase compensation current can be ensured from the rigor of mathematical logic, and the above calculation formula is preferably shown to provide reference, understanding and calculation for technical personnel; in addition, by adopting the above calculation formula to calculate the mobile phase compensation current, that is, comprehensively considering the maximum phase compensation current, the rated current of the first intelligent soft switch and the AC current of the distributed power source to calculate the mobile phase compensation current, a more accurate mobile phase compensation current can be obtained, which can more effectively balance the three-phase current in the system, thereby reducing voltage fluctuations and imbalances, and improving the stability of the entire power system.

[0089] In a second aspect, the present application also provides a distribution network interconnection system based on intelligent soft switches.

[0090] See also Figure 2 , is a schematic diagram of a distribution network interconnection system based on intelligent soft switches in an embodiment of the present application, the system includes a management device and a controller (not shown in the figure) containing intelligent soft switches, the management device containing intelligent soft switches includes a first fixed intelligent soft switch SSOP1, a second fixed intelligent soft switch SSOP2, a third fixed intelligent soft switch SSOP3 and a mobile intelligent soft switch MSOP.

[0091] In a feasible implementation, the controller is respectively connected to the first fixed intelligent soft switch SSOP1, the second fixed intelligent soft switch SSOP2, the third fixed intelligent soft switch SSOP3, and the mobile intelligent soft switch MSOP; the first fixed intelligent soft switch SSOP1 is connected to the maximum phase feeder of the substation, the second fixed intelligent soft switch SSOP2 is connected to the middle phase feeder of the substation, the third fixed intelligent soft switch SSOP3 is connected to the minimum phase feeder of the substation, and the mobile intelligent soft switch MSOP is respectively connected to the maximum phase feeder of the substation and the distributed power source DG; the controller is used to execute a distribution network interconnection system control method based on intelligent soft switches in the above method embodiment.

[0092] It should be noted that in the distribution network area, in addition to phases A, B and C, there is also a phase N, that is, the neutral line. Therefore, please continue to refer to Figure 2 The first fixed intelligent soft switch SSOP1, the second fixed intelligent soft switch SSOP2, the third fixed intelligent soft switch SSOP3, and the mobile intelligent soft switch MSOP are also connected to the zero feeder of the substation; wherein the zero feeder is the feeder corresponding to the N phase.

[0093] Among them, the maximum phase feeder is the feeder corresponding to the phase with the maximum phase-to-be-compensated current, the middle phase feeder is the feeder corresponding to the phase with the middle phase-to-be-compensated current, the minimum phase feeder is the feeder corresponding to the phase with the minimum phase-to-be-compensated current, and the substation includes a first interconnected substation and a second interconnected substation.

[0094] For further explanation, please refer to Figure 2 , Figure 2 Shown in: E l1,1 、E l1,2 and E l1,3 are the phase voltage sources of the three phases corresponding to the A phase, B phase and C phase of the first interconnected station area, I l1,1 ,I l1,2 and I l1,3 are the currents of the three phases corresponding to phase A, phase B and phase C of the first interconnected station area, E l2,1 、E l2,2 and E l2,3 are the phase voltage sources of the three phases corresponding to the A phase, B phase and C phase of the first interconnected station area, I l2,1 ,I l2,2 and I l2,3 They are the currents of the three phases corresponding to phase A, phase B and phase C of the first interconnected station area.

[0095] In the embodiment of the present application, three fixed intelligent soft switches of different capacities (i.e., a first fixed intelligent soft switch SSOP1, a second fixed intelligent soft switch SSOP2, and a third fixed intelligent soft switch SSOP3) are configured, as well as a mobile intelligent soft switch MSOP and a controller. Then, the three-phase current to be compensated in the substation is obtained, and the maximum phase compensation current, the middle phase compensation current, and the minimum phase compensation current are obtained in sequence. When the maximum phase compensation current is greater than the rated current, the AC current of the distributed power source is determined according to the maximum phase compensation current, the rated current, and the AC current of the distributed power source. The mobile phase compensation current is determined, and the first fixed intelligent soft switch SSOP1 is controlled to output the rated current to the maximum phase feeder line of the substation, and the mobile intelligent soft switch MSOP is controlled to output the mobile phase compensation current to the maximum phase feeder line of the substation, and the second fixed intelligent soft switch SSOP2 is controlled to output the intermediate phase compensation current to the intermediate phase feeder line of the substation, and the third fixed intelligent soft switch SSOP3 is controlled to output the minimum phase compensation current to the minimum phase feeder line of the substation, and the substation includes the first interconnected substation and the second interconnected substation; that is, the light and heavy load problems and three-phase imbalance problems of the transformer in the substation are controlled.

[0096] In addition, the present application has flexible phase-by-phase control capabilities, which solves the technical problems existing in the previous research of the present application. It also achieves efficient and comprehensive management of problems such as light and heavy loads, three-phase imbalance and single-phase heavy overloads of transformers in the substation area under low overall capacity. It significantly improves the interconnection and high-quality distribution capabilities of the distribution network, while reducing the configuration cost of the management system, and has important engineering application value.

[0097] Please continue reading Figure 2 The management device containing the intelligent soft switch in the above embodiment also includes a first multi-way switch S1, a second multi-way switch S2, a third multi-way switch S3, a fourth multi-way switch S4, a fifth multi-way switch S5, a sixth multi-way switch S6, a seventh multi-way switch S7 and an eighth multi-way switch S8.

[0098] In a feasible implementation, the first to eighth multi-way switches S1-S8 are all connected to the controller, the first fixed intelligent soft switch SSOP1 is connected to the maximum phase feeder, the middle phase feeder and the minimum phase feeder of the first interconnected station area through the first multi-way switch S1, the second fixed intelligent soft switch SSOP2 is connected to the maximum phase feeder, the middle phase feeder and the minimum phase feeder of the first interconnected station area through the second multi-way switch S2, the third fixed intelligent soft switch SSOP3 is connected to the maximum phase feeder, the middle phase feeder and the minimum phase feeder of the first interconnected station area through the third multi-way switch S3, the mobile intelligent soft switch MSOP is connected to the maximum phase feeder, the middle phase feeder and the minimum phase feeder of the first interconnected station area through the fourth multi-way switch S4, and the first fixed intelligent soft switch SSO P1 is connected to the maximum phase feeder, the middle phase feeder and the minimum phase feeder of the second interconnected station area through the fifth multi-way switch S5, the second fixed intelligent soft switch SSOP2 is connected to the maximum phase feeder, the middle phase feeder and the minimum phase feeder of the second interconnected station area through the sixth multi-way switch S6, the third fixed intelligent soft switch SSOP3 is connected to the maximum phase feeder, the middle phase feeder and the minimum phase feeder of the second interconnected station area through the seventh multi-way switch S7, and the mobile intelligent soft switch MSOP is connected to the maximum phase feeder, the middle phase feeder and the minimum phase feeder of the second interconnected station area through the eighth multi-way switch S8; the controller is also used to control the first multi-way switch to the eighth multi-way switch S1-S8 to conduct to one of the maximum phase feeder, the middle phase feeder and the minimum phase feeder and cut off the other two feeders.

[0099] In the embodiment of the present application, the management device including the intelligent soft switch also includes a first multi-way switch S1, a second multi-way switch S2, a third multi-way switch S3, a fourth multi-way switch S4, a fifth multi-way switch S5, a sixth multi-way switch S6, a seventh multi-way switch S7 and an eighth multi-way switch S8, so that the first fixed intelligent soft switch SSOP1 can be always connected to the maximum phase feeder of the substation (i.e., the first interconnected substation and the second interconnected substation), the second fixed intelligent soft switch SSOP2 can be always connected to the middle phase feeder of the substation, the third fixed intelligent soft switch SSOP3 can be always connected to the minimum phase feeder of the substation, and the mobile intelligent soft switch MSOP can be connected or not connected to the maximum phase feeder of the substation.

[0100] In addition, by precisely controlling the connection of each multi-way switch to different phase feeders, it can ensure that the currents of the maximum phase, middle phase and minimum phase are effectively managed and balanced. This balance helps reduce current surges and voltage fluctuations, thereby improving the stability and reliability of the entire power system.

[0101] Please continue reading Figure 2In the above embodiments, the first fixed intelligent soft switch SSOP1, the second fixed intelligent soft switch SSOP2, the third fixed intelligent soft switch SSOP3 and the mobile intelligent soft switch MSOP are all composed of back-to-back single-phase full-bridge converters.

[0102] In some embodiments, please refer to Figure 2 The back-to-back single-phase full-bridge converter includes eight IGBT devices Q (i.e. Q 11 , Q 12 , Q 13 , Q 14 , Q 21 , Q 22 , Q 23 and Q 24 ), two filter inductors L and a DC side energy storage capacitor C dc .

[0103] In the embodiment of the present application, the first fixed intelligent soft switch SSOP1, the second fixed intelligent soft switch SSOP2, the third fixed intelligent soft switch SSOP3 and the mobile intelligent soft switch MSOP are all composed of back-to-back single-phase full-bridge converters, which can achieve efficient control compensation, so as to achieve efficient and comprehensive management of problems such as light and heavy loads, three-phase imbalance and single-phase heavy overload of transformers in the substation area under low overall capacity.

[0104] In order to verify the effect achieved by this application, this application will be verified by means of simulation. The total capacity of the first interconnected substation and the second interconnected substation is set to 400kVA in the simulation; before the interconnection management, the total load of the first interconnected substation is 350kW, the load of phase A is 135kW, the load of phase B is 110kW, and the load of phase C is 105kW; the total load of the second interconnected substation is 160kW, the load of phase A is 35kW, the load of phase B is 60kW, and the load of phase C is 65kW; that is, the first interconnected substation and the second interconnected substation are both in a three-phase unbalanced state, and the first interconnected substation is in a heavy load state, resulting in a large system loss.

[0105] Furthermore, a first fixed intelligent soft switch SSOP1, a second fixed intelligent soft switch SSOP2 and a third fixed intelligent soft switch SSOP3 are set in the simulation, wherein the capacity of SSOP1 is 35 kVA, the capacity of SSOP2 is 30 kVA, and the capacity of SSOP3 is 25 kVA.

[0106] Exemplarily, between the first interconnected substation and the second interconnected substation, the load current required to be compensated for phase A is transmitted through SSOP1, the load current required to be compensated for phase B is transmitted through SSOP2, and the load current required to be compensated for phase C is transmitted through SSOP3. If phase A cannot be fully transmitted due to the capacity limitation of SSOP1, making it impossible to fully compensate for the load current, it is necessary to continue to transmit and compensate the load current of phase A through the mobile intelligent soft switch MSOP until the load rate of the first interconnected substation is equal to that of the second interconnected substation, and the three-phase imbalance is better resolved.

[0107] See also Figures 3 to 5 , Figure 3 Schematic diagram of the waveform of the three-phase current of the first interconnected substation under various working conditions under simulation in the embodiment of the present application, Figure 4 Schematic diagram of the waveform of the three-phase current of the second interconnected substation under various working conditions in the simulation case in the embodiment of the present application, Figure 5 It is a schematic diagram of a tracking signal of a transmission compensation current of an MSOP under simulation conditions in an embodiment of the present application.

[0108] Depend on Figure 3 and Figure 4 It can be seen that the three phases are unbalanced before 0.1s, and the current value is relatively high. After transmission through SSOP1, SSOP2 and SSOP3 at 0.1s, it can be seen that the currents of phases B and C are in a balanced state. Due to the capacity limitation of SSOP1, the current of phase A is about 150A higher than the current values ​​of phases B and C. After transmission through MSOP at 0.2s, the current of phase A is also well compensated for transmission. The current of each phase of the first interconnected substation and the second interconnected substation is at an effective value of about 386A, and the load rate is equal. The overload of the first interconnected substation has been effectively solved.

[0109] Depend on Figure 5 It can be seen that the tracking signal of the MSOP transmission compensation current is better. After the transmission compensation, the three phases A, B and C are in a three-phase balanced state.

[0110] In a third aspect, the present application also provides a control device for a distribution network interconnection system based on intelligent soft switches.

[0111] See also Figure 4 , is a schematic diagram of a control device for a distribution network interconnection system based on an intelligent soft switch in an embodiment of the present application, wherein the device 410 includes:

[0112] The acquisition and sorting module 411 is used to acquire the three-phase current to be compensated in the substation, and sort the three-phase current to be compensated from high to low to obtain the maximum phase current to be compensated, the middle phase current to be compensated and the minimum phase current to be compensated;

[0113] A judgment and determination module 412, configured to determine a mobile phase compensation current according to the maximum phase compensation current, the rated current and the AC current of the distributed power source when the maximum phase compensation current is greater than the rated current of the first fixed intelligent soft switch;

[0114] The control module 413 is used to control the first fixed intelligent soft switch to output the rated current to the maximum phase feeder of the substation, and control the mobile intelligent soft switch to output the mobile phase compensation current to the maximum phase feeder of the substation, and control the second fixed intelligent soft switch to output the middle phase compensation current to the middle phase feeder of the substation, and control the third fixed intelligent soft switch to output the minimum phase compensation current to the minimum phase feeder of the substation;

[0115] Among them, the maximum phase feeder is the feeder corresponding to the phase with the maximum phase-to-be-compensated current, the middle phase feeder is the feeder corresponding to the phase with the middle phase-to-be-compensated current, the minimum phase feeder is the feeder corresponding to the phase with the minimum phase-to-be-compensated current, and the substation includes a first interconnected substation and a second interconnected substation.

[0116] In the embodiment of the present application, the related contents of the acquisition and sorting module 411, the judgment and determination module 412 and the control module 413 can be found in Figure 1 The contents in the illustrated embodiment will not be described in detail here.

[0117] It should be noted that the device 410 of the present application also includes some other modules. It can be understood that the method of the present application and the device 410 have a one-to-one correspondence. Therefore, some other modules of the device 410 of the present application are the contents corresponding to the method of the present application in the above-mentioned embodiment.

[0118] In an embodiment of the present application, three fixed intelligent soft switches of different capacities (i.e., a first fixed intelligent soft switch, a second fixed intelligent soft switch, and a third fixed intelligent soft switch) are configured, as well as a mobile intelligent soft switch and a controller. Then, the three-phase current to be compensated of the substation is obtained and sorted in sequence to obtain the maximum phase compensation current, the middle phase compensation current, and the minimum phase compensation current. When the maximum phase compensation current is greater than the rated current, the mobile phase compensation current is determined according to the maximum phase compensation current, the rated current, and the AC current of the distributed power source. The first fixed intelligent soft switch is controlled to output the rated current to the maximum phase feeder of the substation, and the mobile intelligent soft switch is controlled to output the mobile phase compensation current to the maximum phase feeder of the substation, and the second fixed intelligent soft switch is controlled to output the middle phase compensation current to the middle phase feeder of the substation, and the third fixed intelligent soft switch is controlled to output the minimum phase compensation current to the minimum phase feeder of the substation. The substation includes a first interconnected substation and a second interconnected substation. That is, the problem of light and heavy load of the transformer and the problem of three-phase imbalance in the substation are solved.

[0119] In addition, the present application has flexible phase-by-phase control capabilities, which solves the technical problems existing in the previous research of the present application. It also achieves efficient and comprehensive management of problems such as light and heavy loads, three-phase imbalance and single-phase heavy overloads of transformers in the substation area under low overall capacity. It significantly improves the interconnection and high-quality distribution capabilities of the distribution network, while reducing the configuration cost of the management system, and has important engineering application value.

[0120] In a fourth aspect, the present application further provides a computer-readable storage medium storing a computer program. When the computer program is executed by a processor, the processor executes a distribution network interconnection system control method based on intelligent soft switches in the above method embodiment.

[0121] In a fifth aspect, the present application further provides a computer device, including a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor executes a distribution network interconnection system control method based on intelligent soft switches in the above method embodiment.

[0122] Figure 7 The internal structure diagram of a computer device in some embodiments is shown. The computer device may be a terminal, a server, or a gateway. Figure 7 As shown, the computer device includes a processor, a memory and a network interface connected through a system bus.

[0123] The memory includes a non-volatile storage medium and an internal memory. The non-volatile storage medium of the computer device stores an operating system and may also store a computer program. When the computer program is executed by the processor, the processor can implement each step in the above method embodiment. The internal memory may also store a computer program. When the computer program is executed by the processor, the processor can implement each step in the above method embodiment. Those skilled in the art can understand that Figure 7 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0124] A person skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be implemented by instructing related hardware through a computer program. The program can be stored in a non-volatile computer-readable storage medium. When the program is executed, it can include the processes of the embodiments of the above-mentioned methods.

[0125] Among them, any reference to memory, storage, database or other media used in the embodiments provided in the present application may include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. As an illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synch li nk) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0126] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0127] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A control method for a distribution network interconnection system based on intelligent soft switches, characterized in that: The method comprises: Acquire three-phase currents to be compensated in the substation, and sort the three-phase currents to be compensated in order from high to low to obtain a maximum current to be compensated, an intermediate current to be compensated, and a minimum current to be compensated; In the case where the maximum phase-to-phase compensation current is greater than the rated current of the first fixed intelligent soft switch, determining the mobile phase-to-phase compensation current according to the maximum phase-to-phase compensation current, the rated current and the AC current of the distributed power source; Control the first fixed intelligent soft switch to output the rated current to the maximum phase feeder of the substation, control the mobile intelligent soft switch to output the mobile phase compensation current to the maximum phase feeder of the substation, control the second fixed intelligent soft switch to output the middle phase compensation current to the middle phase feeder of the substation, and control the third fixed intelligent soft switch to output the minimum phase compensation current to the minimum phase feeder of the substation; Among them, the maximum phase feeder is the feeder of the phase corresponding to the maximum phase current to be compensated, the middle phase feeder is the feeder of the phase corresponding to the middle phase current to be compensated, the minimum phase feeder is the feeder of the phase corresponding to the minimum phase current to be compensated, and the substation includes a first interconnected substation and a second interconnected substation.

2. The method according to claim 1, characterized in that The step of obtaining the three-phase current to be compensated in the transformer area includes: Obtaining the three-phase negative-sequence current to be compensated, the three-phase zero-sequence current to be compensated and the three-phase load current to be compensated of the first interconnected substation, and the three-phase negative-sequence current to be compensated, the three-phase zero-sequence current to be compensated and the load current required for three-phase voltage stabilization of the second interconnected substation; The three-phase current to be compensated in the first interconnected substation is determined according to the three-phase negative-sequence current to be compensated, the three-phase zero-sequence current to be compensated and the three-phase load current to be compensated in the first interconnected substation, and the three-phase current to be compensated in the second interconnected substation is determined according to the three-phase negative-sequence current to be compensated, the three-phase zero-sequence current to be compensated and the load current required for three-phase voltage stability in the second interconnected substation.

3. The method according to claim 2, characterized in that The obtaining of the three-phase negative-sequence current to be compensated, the three-phase zero-sequence current to be compensated and the three-phase load current to be compensated of the first interconnected substation, and the three-phase negative-sequence current to be compensated, the three-phase zero-sequence current to be compensated and the load current required for three-phase voltage stabilization of the second interconnected substation includes: Acquire the three-phase current of the first interconnected substation and the three-phase current of the second interconnected substation, and the power to be transmitted between the first interconnected substation and the second interconnected substation, wherein the power to be transmitted is the power that the first interconnected substation needs to transmit to the second interconnected substation when the load rate of the first interconnected substation is equal to the load rate of the second interconnected substation; Decomposing the three-phase current of the first interconnected substation by sequence components to obtain the three-phase negative-sequence current to be compensated and the three-phase zero-sequence current to be compensated of the first interconnected substation, and decomposing the three-phase current of the second interconnected substation by sequence components to obtain the three-phase negative-sequence current to be compensated and the three-phase zero-sequence current to be compensated of the second interconnected substation; The three-phase load current to be compensated in the first interconnected area and the three-phase load current required for voltage stabilization in the second interconnected area are determined according to the power to be transmitted.

4. The method according to claim 2 or 3, characterized in that: The method of determining the three-phase current to be compensated in the first interconnected area according to the three-phase negative-sequence current to be compensated, the three-phase zero-sequence current to be compensated and the three-phase load current to be compensated in the first interconnected area, and determining the three-phase current to be compensated in the second interconnected area according to the three-phase negative-sequence current to be compensated, the three-phase zero-sequence current to be compensated and the load current required for three-phase voltage stabilization in the second interconnected area includes: Using the formula Determine the three-phase current to be compensated in the first interconnected area, and use the formula Determining the three-phase current to be compensated in the second interconnected substation; Among them, I l1_ref,1 ,I l1_ref,2 and I l1_ref,3 are respectively a first phase current to be compensated, a second phase current to be compensated and a third phase current to be compensated among the three phase currents to be compensated in the first interconnected substation, and are respectively a first phase load current to be compensated, a second phase load current to be compensated and a third phase load current to be compensated among the three-phase load currents to be compensated in the first interconnected substation, and are respectively the first phase negative sequence current to be compensated, the second phase negative sequence current to be compensated and the third phase negative sequence current to be compensated of the three-phase negative sequence current to be compensated in the first interconnected substation, and are respectively the first phase zero-sequence current to be compensated, the second phase zero-sequence current to be compensated and the third phase zero-sequence current to be compensated in the three-phase zero-sequence current to be compensated in the first interconnected substation, I l2_ref,1 ,I l2_ref,2 and I l2_ref,3 are respectively a first phase current to be compensated, a second phase current to be compensated and a third phase current to be compensated among the three phase currents to be compensated in the second interconnected substation, and are respectively a first phase load current to be compensated, a second phase load current to be compensated and a third phase load current to be compensated among the three-phase load current to be compensated of the second interconnected substation, and are respectively the first phase negative sequence current to be compensated, the second phase negative sequence current to be compensated and the third phase negative sequence current to be compensated among the three-phase negative sequence current to be compensated in the second interconnected substation, and They are respectively the first phase zero-sequence current to be compensated, the second phase zero-sequence current to be compensated and the third phase zero-sequence current to be compensated among the three-phase zero-sequence current to be compensated in the second interconnected substation.

5. The method according to claim 1, characterized in that The determining of the motorized phase compensation current according to the maximum phase compensation current, the rated current and the AC current of the distributed power source comprises: Using the formula Determining the motor phase compensation current; in, is the motor phase compensation current, I l1orl2_ref,1or2or3 is the maximum phase compensation current, I N is the rated current, I DG is the AC current of the distributed power source.

6. A distribution network interconnection system based on intelligent soft switches, characterized in that: The system includes a management device including an intelligent soft switch and a controller, wherein the management device including the intelligent soft switch includes a first fixed intelligent soft switch, a second fixed intelligent soft switch, a third fixed intelligent soft switch and a mobile intelligent soft switch; The controller is connected to the first fixed intelligent soft switch, the second fixed intelligent soft switch, the third fixed intelligent soft switch, and the mobile intelligent soft switch respectively; the first fixed intelligent soft switch is connected to the maximum phase feeder of the substation; the second fixed intelligent soft switch is connected to the middle phase feeder of the substation; the third fixed intelligent soft switch is connected to the minimum phase feeder of the substation; and the mobile intelligent soft switch is connected to the maximum phase feeder and the distributed power source of the substation respectively; The controller is used to perform the method according to any one of claims 1 to 5; Among them, the maximum phase feeder is the feeder of the phase corresponding to the maximum phase current to be compensated, the middle phase feeder is the feeder of the phase corresponding to the middle phase current to be compensated, the minimum phase feeder is the feeder of the phase corresponding to the minimum phase current to be compensated, and the substation includes a first interconnected substation and a second interconnected substation.

7. The system according to claim 6, characterized in that The management device including the intelligent soft switch also includes a first multi-way switch, a second multi-way switch, a third multi-way switch, a fourth multi-way switch, a fifth multi-way switch, a sixth multi-way switch, a seventh multi-way switch and an eighth multi-way switch; The first to the eighth multi-way switches are all connected to the controller, the first fixed intelligent soft switch is connected to the maximum phase feeder, the middle phase feeder and the minimum phase feeder of the first interconnected substation through the first multi-way switch, the second fixed intelligent soft switch is connected to the maximum phase feeder, the middle phase feeder and the minimum phase feeder of the first interconnected substation through the second multi-way switch, the third fixed intelligent soft switch is connected to the maximum phase feeder, the middle phase feeder and the minimum phase feeder of the first interconnected substation through the third multi-way switch, the mobile intelligent soft switch is connected to the maximum phase feeder, the middle phase feeder and the minimum phase feeder of the first interconnected substation through the third multi-way switch, The first fixed intelligent soft switch is connected to the maximum phase feeder line, the middle phase feeder line and the minimum phase feeder line of the second interconnected substation through the fourth multi-way switch, the first fixed intelligent soft switch is connected to the maximum phase feeder line, the middle phase feeder line and the minimum phase feeder line of the second interconnected substation through the fifth multi-way switch, the second fixed intelligent soft switch is connected to the maximum phase feeder line, the middle phase feeder line and the minimum phase feeder line of the second interconnected substation through the sixth multi-way switch, the third fixed intelligent soft switch is connected to the maximum phase feeder line, the middle phase feeder line and the minimum phase feeder line of the second interconnected substation through the seventh multi-way switch, and the mobile intelligent soft switch is connected to the maximum phase feeder line, the middle phase feeder line and the minimum phase feeder line of the second interconnected substation through the eighth multi-way switch; The controller is further used to control the first to eighth multi-way switches to respectively switch on one of the maximum phase feeder, the middle phase feeder and the minimum phase feeder and cut off the remaining two feeders.

8. The system according to claim 6, characterized in that The first fixed intelligent soft switch, the second fixed intelligent soft switch, the third fixed intelligent soft switch and the mobile intelligent soft switch are all composed of back-to-back single-phase full-bridge converters.

9. A computer-readable storage medium, characterized in that: A computer program is stored, and when the computer program is executed by a processor, the processor is caused to perform the method according to any one of claims 1 to 5.

10. A computer device, characterized in that: The method comprises a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the method according to any one of claims 1 to 5.

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