Control system of hybrid distribution transformer cluster and method of operation thereof

Abstract

The application provides a control system of a hybrid distribution transformer cluster and a running method thereof, and the system comprises a cluster instruction module, a plurality of decentralized coordination control modules and a plurality of hybrid distribution transformer modules; the cluster instruction module is used for calculating the control instruction value of each decentralized coordination control module in the cluster according to an external dispatching instruction and distribution network area information; the decentralized coordination control module is used for generating a control signal according to the control instruction value, and sending the control signal to the corresponding hybrid distribution transformer module to perform coordinated control on the output port of the hybrid distribution transformer module and perform voltage compensation when the low-voltage AC bus voltage drops. Thus, through the decentralized coordination control and voltage compensation, the stable work of the hybrid distribution transformer as the core equipment of the smart distribution network and the interconnected and coordinated operation of the smart distribution network area can be ensured, so that the efficient and reliable supply of electric energy can be realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of communication technology, in particular to a control system of a hybrid distribution transformer cluster and an operation method of the system. BACKGROUND

[0002] Compared with the traditional distribution transformer, the hybrid distribution transformer not only has the advantages of high efficiency and reliability of the traditional distribution transformer, but also can greatly improve the controllability of the traditional distribution transformer, and therefore is very suitable for the development needs of the intelligentization of future distribution networks.

[0003] Due to the flexible and controllable characteristics of the hybrid distribution transformer (HDT) in power transmission, the HDT becomes a key joint of energy conversion in the smart distribution network. When actually applied to the distribution network, the HDT needs to operate in the form of a cluster of multiple units. Therefore, how to realize efficient and reliable power supply, as well as the new networking form and corresponding operation mode of the HDT cluster access in the distribution network become the basis and core of the future smart distribution network. SUMMARY

[0004] To solve one of the above technical problems, the present application proposes the following technical solutions.

[0005] The first aspect of the present application proposes a control system of a hybrid distribution transformer cluster, comprising:

[0006] a cluster instruction module, a plurality of decentralized coordination control modules and a plurality of hybrid distribution transformer modules, wherein the cluster instruction module is connected with the plurality of decentralized coordination control modules, the plurality of decentralized coordination control modules are connected with the plurality of hybrid distribution transformer modules one by one, and each hybrid distribution transformer module corresponds to a low-voltage distribution network area.

[0007] The cluster instruction module is configured to receive an external dispatching instruction and low-voltage distribution network area information, calculate a control instruction value of each decentralized coordination control module in the cluster according to the external dispatching instruction and the distribution network area information, and send the control instruction value to the corresponding decentralized coordination control module.

[0008] The decentralized coordination control module is configured to generate a control signal according to the control instruction value, and send the control signal to the corresponding hybrid distribution transformer module to perform coordinated control on the output port of the hybrid distribution transformer module and perform voltage compensation when a low-voltage AC bus voltage drops, wherein the output port of the hybrid distribution transformer includes a low-voltage AC bus output port and a low-voltage DC bus output port.

[0009] In addition, the control system of the hybrid distribution transformer cluster according to the above-mentioned embodiment of the present application can further have the following additional technical features.

[0010] According to an embodiment of the present application, the hybrid distribution transformer module comprises a multi-winding transformer unit, a filter inductor unit and a power quality control unit.

[0011] The multi-winding transformer unit is configured to convert high-voltage alternating current into low-voltage alternating current and provide power supply for the power quality control unit.

[0012] The power quality control unit is configured to provide the hybrid distribution transformer module with a low-voltage DC bus output port and voltage compensation function.

[0013] According to an embodiment of the present application, the multi-winding transformer unit comprises three-phase windings, each of which comprises a first winding, a second winding and a third winding, the filter inductor unit comprises three filter inductors, the first winding is connected to the primary winding of the high-voltage AC bus, the second winding is connected to the secondary winding of the low-voltage AC bus and serves as the low-voltage AC bus output port of the hybrid distribution transformer module, and the three third windings are connected to the power quality control unit in series one by one with the three filter inductors.

[0014] According to an embodiment of the present application, the multi-winding transformer unit comprises three-phase windings, each of which comprises a first winding, a second winding and a third winding, the filter inductor unit comprises three filter inductors, the first winding is connected to the primary winding of the high-voltage AC bus, the second winding is connected to the secondary winding of the low-voltage AC bus and serves as the low-voltage AC bus output port of the hybrid distribution transformer module, and the three third windings are connected to the power quality control unit in series one by one with the three filter inductors.

[0015] According to an embodiment of the present application, the control instruction value comprises a controller reference value in the decentralized coordinated control module, and the controller reference value comprises a power reference value, a DC voltage reference value and an AC voltage reference value.

[0016] The decentralized coordinated control module comprises a distribution network area information acquisition unit, a power controller, a low-voltage DC bus voltage controller and a voltage compensation output controller.

[0017] The distribution network area information acquisition unit is configured to acquire distribution network area information, and the distribution network area information comprises DC voltage information, AC voltage information and AC grid frequency information of a low-voltage distribution network area, and input power information and output power information of the hybrid distribution transformer module.

[0018] The power controller is configured to obtain a power reference value from the control instruction value, control power absorbed by a power distribution network area internally according to the power reference value, and coordinate control of distributed power generation in the area.

[0019] The low-voltage DC bus voltage controller is configured to obtain a DC voltage reference value from the control instruction value, and control a low-voltage DC bus voltage output by a DC bus capacitor of the power quality control unit to be equal to the DC voltage reference value.

[0020] The voltage compensation output controller is configured to obtain an AC voltage reference value from the control instruction value when the distributed coordination control module detects a low-voltage AC distribution bus drop, and control a low-voltage AC compensation voltage output by the three-phase AC / DC converter of the power quality control unit to be equal to the AC voltage reference value.

[0021] According to an embodiment of the present application, the cluster instruction module, when calculating the control instruction value of each distributed coordination control module in the cluster according to the external scheduling instruction and the power distribution network area information, is specifically configured to:

[0022] The power imbalance of the hybrid distribution transformer module in the cluster is distributed by using a consistency algorithm, and the control instruction value of each distributed coordination control module in the cluster is calculated based on the power imbalance of the hybrid distribution transformer.

[0023] The second aspect embodiment of the present application proposes a running method of the control system of the hybrid distribution transformer cluster proposed in the first aspect embodiment of the present application, comprising:

[0024] The cluster instruction module receives an external scheduling instruction and low-voltage power distribution network area information, calculates a control instruction value of each distributed coordination control module in the cluster according to the external scheduling instruction and the power distribution network area information, and sends the control instruction value to the corresponding distributed coordination control module.

[0025] The distributed coordination control module controls the system to enter a normal running mode or a voltage drop mode according to the corresponding control instruction value, to coordinate control of the output port of the hybrid distribution transformer module, and to perform voltage compensation when a low-voltage AC bus drop occurs, wherein the output port of the hybrid distribution transformer includes a low-voltage AC bus output port and a low-voltage DC bus output port.

[0026] According to an embodiment of the present application, the distributed coordination control module controls the system to enter a normal running mode according to the corresponding control instruction value, comprising:

[0027] When the low-voltage AC bus voltage is determined not to drop, according to the control instruction value received from the cluster instruction module, the low-voltage distribution area internal power absorbed is adjusted by the droop control method through the power controller and the low-voltage DC bus voltage controller according to the low-voltage DC bus voltage and the low-voltage AC bus frequency.

[0028] According to the control instruction value received from the cluster instruction module, the distributed power in the low-voltage distribution network is coordinated to adjust the output according to the AC frequency of the low-voltage AC bus or the low-voltage DC bus voltage through the power controller and the self-power controller of the distributed power.

[0029] According to one embodiment of the present application, the distributed coordination control module controls the system to enter the voltage drop mode according to the corresponding control instruction value, comprising:

[0030] After detecting the low-voltage AC distribution bus voltage drop, the voltage compensation output controller controls the power quality control module to output compensation voltage to compensate for the low-voltage AC distribution bus voltage.

[0031] The technical scheme of the embodiment of the present application can ensure the stable operation of the hybrid distribution transformer as the core equipment of the smart distribution network and the interconnected and coordinated operation of the smart distribution network area, so as to realize efficient and reliable supply of electric energy. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 It is a structure schematic diagram of the control system of the hybrid distribution transformer cluster of the embodiment of the present application.

[0033] Figure 2 It is a connection schematic diagram of each module in the control system of the hybrid distribution transformer cluster of one embodiment of the present application.

[0034] Figure 3 It is a circuit topology diagram of the hybrid distribution transformer module of one example of the present application.

[0035] Figure 4 It is a simulation curve of the three-phase low-voltage AC bus voltage when voltage drop occurs before compensation according to one example of the present application.

[0036] Figure 5 It is a simulation curve of the three-phase low-voltage AC bus voltage when voltage drop occurs after compensation according to one example of the present application.

[0037] Figure 6 It is a flowchart of the operation method of the control system of the hybrid distribution transformer cluster of the embodiment of the present application. DETAILED DESCRIPTION

[0038] With reference to the accompanying drawings, the technical solutions in the embodiments of the present application will be described clearly and completely. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application.

[0039] Figure 1 A structural schematic diagram of a control system of a hybrid distribution transformer cluster in an embodiment of the present application.

[0040] As shown in Figure 1 , the control system of the hybrid distribution transformer cluster comprises a cluster instruction module 1, a plurality of decentralized coordination control modules 2 and a plurality of hybrid distribution transformer modules 3, wherein the cluster instruction module 1 is connected with the plurality of decentralized coordination control modules 2, the plurality of decentralized coordination control modules 2 are connected with the plurality of hybrid distribution transformer modules 3 one by one (three decentralized coordination control modules 2 are connected with three hybrid distribution transformer modules 3 as shown in Figure 1 ), and each hybrid distribution transformer module 3 corresponds to a low-voltage distribution network area.

[0041] The cluster instruction module 1 is configured to receive external dispatching instructions and low-voltage distribution network area information, calculate control instruction values of each decentralized coordination control module 2 in the cluster according to the external dispatching instructions and the distribution network area information, and send the control instruction values to the corresponding decentralized coordination control module 2; the decentralized coordination control module 2 is configured to generate a control signal according to the control instruction value, and send the control signal to the corresponding hybrid distribution transformer module 3 to perform coordinated control on the output port of the hybrid distribution transformer module 3 and perform voltage compensation when a low-voltage AC bus voltage drops, wherein the output port of the hybrid distribution transformer module 3 comprises a low-voltage AC bus output port and a low-voltage DC bus output port.

[0042] It should be noted that the regional distribution network in the embodiment of the present application is composed of a plurality of low-voltage distribution network areas in the region, each area refers to a low-voltage distribution network area powered by a hybrid distribution transformer module, as shown in Figure 2 , each area can include a low-voltage bus connected with the low-voltage outlet of the hybrid distribution transformer module, a load, a distributed power supply and the like.

[0043] In one embodiment, with reference to Figure 2Each hybrid distribution transformer module 3 is connected to a high voltage alternating current (HVAC) bus through its HVAC port, each hybrid distribution transformer module 3 is connected to a low voltage alternating current (LVAC) bus through its LVAC bus output port, each hybrid distribution transformer module 3 is connected to a low voltage direct current (LVDC) bus through its LVDC bus output port, the LVAC bus supplies power to a plurality of power frequency alternating current loads, the LVDC bus supplies power to a distributed power source or an energy storage system through a DC / DC converter, and the LVDC bus also supplies power to a direct current load.

[0044] Specifically, in actual application, a dispatcher responsible for dispatching the regional distribution network can issue an external dispatching instruction to the cluster instruction module 1 through a dispatching center, the cluster instruction module 1 receives the external dispatching instruction, obtains the information of each low-voltage distribution network station area, calculates the control instruction value of each decentralized coordination control module 2 in the cluster according to the external dispatching instruction and the distribution network station area information, and sends the control instruction value to the corresponding decentralized coordination control module 2, and then the decentralized coordination control module 2 receives the control instruction value, generates a control signal according to the control instruction value, and sends the control signal to the corresponding hybrid distribution transformer module 3 to coordinate and control the low-voltage alternating current bus output port and the low-voltage direct current bus output port of the hybrid distribution transformer module 3, and perform voltage compensation when the low-voltage alternating current bus voltage drops.

[0045] It should be noted that the control instruction value can be a related control parameter for controlling the hybrid distribution transformer module by the decentralized coordination control module or each control unit in the module, for example, the control instruction value is a controller parameter and a reference value in each decentralized coordination control module, the controller parameter mainly refers to a proportional coefficient and an integral coefficient of a proportional integral controller and a proportional coefficient and a resonance coefficient of a proportional resonance controller, and the controller reference value mainly includes a power reference value and a voltage reference value.

[0046] Therefore, the control system of the hybrid distribution transformer cluster of the embodiment of the present application can ensure the stable operation of the hybrid distribution transformer as the core equipment of the smart distribution network and the interconnected and coordinated operation of the smart distribution network station area through decentralized coordination control and voltage compensation, so that efficient and reliable supply of electric energy can be realized.

[0047] In an embodiment of the present application, as Figure 3As shown, the hybrid distribution transformer module 3 comprises a multi-winding transformer unit 31, a filter inductor unit 32 and a power quality control unit 33. The multi-winding transformer unit 31 is used to convert high-voltage alternating current into low-voltage alternating current and provide power for the power quality control unit 33; the filter inductor unit 32 is used to filter the low-voltage alternating current; and the power quality control unit 33 is used to provide a low-voltage DC bus output port and voltage compensation function for the hybrid distribution transformer module 3.

[0048] In this embodiment, with reference to Figure 3 , the multi-winding transformer unit 31 comprises three-phase windings, respectively named A-phase, B-phase and C-phase, wherein each phase winding comprises a first winding r1, a second winding r2 and a third winding r3, the filter inductor unit 32 comprises three filter inductors L, the first winding r1 is connected to the primary winding of the high-voltage AC bus, the second winding r2 is connected to the secondary winding of the low-voltage AC bus and serves as the low-voltage AC bus output port of the hybrid distribution transformer module 3; and the three third windings r3 are connected in series with the three filter inductors L one by one and then connected to the power quality control unit 33.

[0049] Continuing to refer to Figure 3 , the power quality control unit 33 comprises a three-phase AC / DC converter 331 for converting alternating current into direct current, a three-phase DC / AC converter 332 for converting direct current into alternating current and a DC bus capacitor C; the three-phase AC terminals of the three-phase AC / DC converter 331 are connected to the three third windings r3 of the multi-winding transformer unit 31 one by one; the three-phase AC terminals of the three-phase DC / AC converter 332 are connected to the first ends of the three second windings r2 of the multi-winding transformer unit 31 one by one; and the DC bus capacitor C provides a low-voltage DC bus output port for the hybrid distribution transformer module 3.

[0050] That is, the second winding r21 of the multi-winding transformer unit 31 serves as the low-voltage AC bus output port of the hybrid distribution transformer module 3, the AC output terminal of the three-phase DC / AC converter 332 of the power quality control unit 33 serves as the low-voltage AC bus output port of the hybrid distribution transformer module 3, and the output terminal of the DC bus capacitor C of the power quality control unit 33 serves as the low-voltage DC bus output port of the hybrid distribution transformer module 3.

[0051] Specifically, the multi-winding transformer unit 31 converts high-voltage alternating current into low-voltage alternating current, and the low-voltage alternating current is filtered by the filter inductor unit 32, and then the power quality control unit 33 is powered, and the decentralized coordinated control module 2 controls the corresponding power quality control unit 33 according to the control instruction value sent by the cluster instruction module, that is, controls the three-phase AC-DC converter 331 and the three-phase DC-AC converter 332 of the power quality control unit 33, to realize the coordinated control of the low-voltage AC bus output port and the low-voltage DC bus output port of the hybrid distribution transformer.

[0052] In an embodiment of the present application, the control instruction value includes a controller reference value in the decentralized coordinated control module, and the controller reference value includes a power reference value, a DC voltage reference value, and an AC voltage reference value; the decentralized coordinated control module includes: a power distribution network area information acquisition unit, a power controller, a low-voltage DC bus voltage controller, and a voltage compensation output controller.

[0053] The power distribution network area information acquisition unit is configured to acquire power distribution network area information, and the power distribution network area information includes: DC voltage information, AC voltage information, and AC grid frequency information of the low-voltage power distribution network area, and input power information and output power information of the hybrid distribution transformer module; the power controller is configured to obtain the power reference value from the control instruction value, and control the power absorbed by the power distribution network area and the distributed power generation in the area according to the power reference value; the low-voltage DC bus voltage controller is configured to obtain the DC voltage reference value from the control instruction value, and control the low-voltage DC bus voltage output by the DC bus capacitor of the power quality control unit to be equal to the DC voltage reference value; and the voltage compensation output controller is configured to obtain the AC voltage reference value from the control instruction value when the decentralized coordinated control module detects a low-voltage AC distribution bus drop, and control the low-voltage AC compensation voltage output by the three-phase AC-DC converter of the power quality control unit to be equal to the AC voltage reference value.

[0054] Wherein, the power reference value refers to the reference value (also known as the ideal value) of the power to be output by the power controller in the decentralized coordinated control module, and the voltage reference value refers to the ideal value that the bus voltage is expected to reach through the decentralized coordinated control module, mainly to indicate that the controller controls the controlled object (here referring to the power quality control unit) to make the physical quantity (here referring to the bus voltage) output by the controlled object equal to the reference value.

[0055] Specifically, after receiving the controller reference value of the decentralized coordinated control module 2, it can first determine whether the low-voltage AC distribution bus voltage is normal, and in the case of normal low-voltage AC distribution bus voltage, it enters the normal operation mode, that is, it runs in the normal operation mode before detecting the low-voltage AC distribution bus voltage drop; after detecting the low-voltage AC distribution bus voltage drop, it enters the voltage drop mode.

[0056] The normal operation mode is: the decentralized coordination control module 2 adjusts the power absorbed in the low-voltage distribution area according to the control instruction value received from the cluster instruction module, the low-voltage DC bus voltage and the low-voltage AC bus frequency, through the power controller and the low-voltage DC bus voltage controller, by using the droop control method, so as to balance the power absorbed and consumed in each area through the DC bus distribution power, and then the decentralized coordination control module adjusts the power output of the distributed power according to the control instruction value received from the cluster instruction module, through the power controller, the power controller of the distributed power, and the low-voltage distribution network, so as to balance the power absorbed and consumed in each area through the DC bus distribution power.

[0057] The power controller controls the power absorbed in the distribution network area according to the power reference value, and coordinates the control of the distributed power in the area, so as to balance the power absorbed and consumed in each area through the DC bus distribution power. The low-voltage DC bus voltage controller controls the low-voltage DC bus voltage output by the power quality control unit to be equal to the DC voltage reference value.

[0058] The voltage drop mode is: after detecting the voltage drop of the low-voltage AC distribution bus, the decentralized coordination control module 2 controls the power quality control unit 33 to output compensation voltage through the voltage compensation output controller to compensate for the low-voltage AC distribution bus voltage. The voltage compensation output controller controls the low-voltage AC compensation voltage output by the three-phase AC / DC converter of the power quality control unit to be equal to the AC voltage reference value, so as to compensate for the AC distribution bus voltage.

[0059] In an embodiment of the present application, the cluster instruction module, when used to calculate the control instruction value of each decentralized coordination control module in the cluster according to the external scheduling instruction and the distribution network area information, can be specifically used to: distribute the power imbalance of the hybrid distribution transformer module in the cluster by using a consensus algorithm, and calculate the control instruction value of each decentralized coordination control module in the cluster based on the power imbalance of the hybrid distribution transformer.

[0060] Specifically, the consensus algorithm here can refer to an iterative process that makes the state variables of each node in the distribution network converge to the same value (i.e., to the average value). The power imbalance refers to the difference between the power generated by the distributed power supply and the power consumed by the load in the area. The embodiment of the present application can use a time-consensus algorithm to take the power imbalance of each transformer module corresponding to the area as a consensus variable, and finally obtain the average value of the power imbalance convergence in each area through iterative calculation, and perform power distribution according to the average value of the power imbalance, so as to realize full consumption of electric energy in each distribution area.

[0061] Based on the above description, the operation method of the control system of the hybrid distribution transformer cluster of the embodiment of the application comprises two modes of normal operation and voltage drop;

[0062] The normal operation mode refers to a control method operation mode in the case of normal voltage of all low-voltage alternating current distribution busbars, and the operation method steps in the normal operation mode are specifically as follows:

[0063] (1) The cluster instruction module distributes the power imbalance of the hybrid distribution transformer in the cluster according to the external dispatching instruction and the distribution network area information, and calculates the control instruction value of each decentralized coordination control module in the cluster according to the power imbalance, and sends the control instruction value to the decentralized coordination control module by using a consistency algorithm.

[0064] (2) The decentralized coordination control module adjusts the power absorbed in the low-voltage distribution area by using the droop control method through the power controller and the low-voltage direct current busbar voltage controller according to the control instruction value received from the cluster instruction module and the low-voltage direct current busbar voltage and the low-voltage alternating current busbar frequency.

[0065] (3) The decentralized coordination control module communicates with the power controller of the distributed power source through the power controller according to the control instruction value received from the cluster instruction module, and coordinates the distributed power source in the low-voltage distribution network to adjust the output of the distributed power source connected in the transformer area according to the alternating current frequency of the low-voltage alternating current busbar or the low-voltage direct current busbar voltage.

[0066] The voltage drop mode refers to a control method operation mode in the case that the decentralized coordination control module detects a voltage drop accident of the low-voltage alternating current distribution busbar, and the operation method steps in the voltage drop mode are specifically as follows:

[0067] (1) Before detecting the voltage drop of the low-voltage alternating current distribution busbar, the control system is operated in the normal operation mode.

[0068] (2) After detecting the voltage drop of the low-voltage alternating current distribution busbar, the decentralized coordination control module controls the power quality control module to output a compensation voltage through the voltage compensation output controller to compensate the low-voltage alternating current distribution busbar voltage.

[0069] In a specific example, when the low-voltage alternating current busbar voltage drops, if no voltage compensation is performed, the low-voltage alternating current busbar voltage is provided as shown in FIG. 8, while through the control system of the hybrid distribution transformer cluster of the embodiment of the application, the low-voltage alternating current busbar voltage drop can be detected in time, and the voltage can be compensated quickly when the voltage drops, so that the low-voltage alternating current busbar voltage is provided as shown in FIG. 9, thereby ensuring reliable supply of electric energy. Figure 4 Figure 5 Figure 4 ​​is a simulation curve of three-phase low-voltage AC bus voltage after the voltage drop occurs according to an example of the application applying the hybrid distribution transformer compensation. Figure 5 is a simulation curve of three-phase low-voltage AC bus voltage after the voltage drop occurs according to an example of the application applying the hybrid distribution transformer compensation.

[0070] By comparison Figure 4 and Figure 5 It can be seen that the distributed coordination control module can realize rapid compensation of three-phase low-voltage AC bus voltage through the coordination control method under the voltage drop mode after the voltage drop of the low-voltage AC distribution bus, and avoid the problem of insufficient power supply caused by the voltage drop.

[0071] In summary, the embodiment of the application provides a control system of a hybrid distribution transformer cluster and an operation method thereof. The system adopts a multi-hybrid intelligent transformer cluster AC-DC hybrid architecture in a district, which can accommodate various distributed power and AC-DC load access, is conducive to realizing the double-carbon target, and the control method under the two modes proposed realizes efficient and reliable operation of the cluster system and rapid compensation for voltage drop, and improves the power quality of the low-voltage distribution network.

[0072] Figure 6 The flowchart of the operation method of the control system of the hybrid distribution transformer cluster of the embodiment of the application.

[0073] As Figure 6 shown, the operation method comprises the following steps:

[0074] S1, the cluster instruction module receives external scheduling instructions and low-voltage distribution network district information, calculates the control instruction value of each distributed coordination control module in the cluster according to the external scheduling instructions and the distribution network district information, and sends the control instruction value to the corresponding distributed coordination control module.

[0075] S2, the distributed coordination control module controls the system to enter a normal operation mode or a voltage drop mode according to the corresponding control instruction value, so as to control the output port of the hybrid distribution transformer module, and compensate the voltage when the low-voltage AC bus drops, wherein the output port of the hybrid distribution transformer module includes a low-voltage AC bus output port and a low-voltage DC bus output port.

[0076] Further, the distributed coordination control module controls the system to enter a normal operation mode according to the corresponding control instruction value, which can include:

[0077] When it is determined that the low-voltage AC bus voltage does not drop, according to the control instruction value received from the cluster instruction module, the power absorbed in the low-voltage distribution area is adjusted by using the droop control method through the power controller and the low-voltage DC bus voltage controller according to the low-voltage DC bus voltage and the low-voltage AC bus frequency.

[0078] According to the control instruction value received from the cluster instruction module, the power of the distributed power supply in the low-voltage distribution network is adjusted according to the AC frequency of the low-voltage AC bus or the low-voltage DC bus voltage through the power controller and the power controller of the distributed power supply.

[0079] Further, the decentralized coordination control module controls the system to enter the voltage drop mode according to the corresponding control instruction value, which can include:

[0080] After detecting the voltage drop of the low-voltage AC distribution bus, the voltage compensation output controller controls the power quality control module to output compensation voltage to compensate for the low-voltage AC distribution bus voltage.

[0081] The operation method of the control system of the hybrid distribution transformer cluster of the embodiment of the application can ensure the stable operation of the hybrid distribution transformer as the core equipment of the smart distribution network and the interconnected and coordinated operation of the smart distribution network area, thereby realizing efficient and reliable supply of electric energy.

[0082] In the description of the present application, the terms "first", "second" are only used for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first", "second" can explicitly or implicitly include one or more of the features. The meaning of "a plurality of" is two or more, unless otherwise specifically limited.

[0083] In the description of the present application, the description of the terms "one embodiment", "some embodiments", "example", "specific example" or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In the present application, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Although the embodiments of the present application have been shown and described above, it should be understood that the above embodiments are exemplary and cannot be understood as limiting the present application, and those skilled in the art can make changes, modifications, replacements and variations to the above embodiments within the scope of the present application.

Claims

1. A control system for a cluster of hybrid distribution transformers, the control system comprising: The application relates to a cluster instruction module, a plurality of decentralized coordination control modules and a plurality of hybrid power distribution transformer modules, wherein the cluster instruction module is connected with the plurality of decentralized coordination control modules, the plurality of decentralized coordination control modules are connected with the plurality of hybrid power distribution transformer modules one by one, and each hybrid power distribution transformer module corresponds to a low-voltage power distribution network area. The cluster instruction module is used for receiving external scheduling instructions and low-voltage power distribution network area information, calculating control instruction values of each decentralized coordination control module in the cluster according to the external scheduling instructions and the power distribution network area information, and sending the control instruction values to the corresponding decentralized coordination control modules. The decentralized coordination control module is used for generating control signals according to the control instruction values, sending the control signals to the corresponding hybrid power distribution transformer modules, and performing coordinated control on output ports of the hybrid power distribution transformer modules and voltage compensation when low-voltage alternating current bus voltage drops, wherein the output ports of the hybrid power distribution transformer include low-voltage alternating current bus output ports and low-voltage direct current bus output ports. The control instruction values include controller reference values in the decentralized coordination control module, the controller reference values include power reference values, direct current voltage reference values and alternating current voltage reference values; the decentralized coordination control module includes a power distribution network area information acquisition unit, a power controller, a low-voltage direct current bus voltage controller and a voltage compensation output controller; the power distribution network area information acquisition unit is used for acquiring power distribution network area information, the power distribution network area information includes direct current voltage information, alternating current voltage information and alternating current grid frequency information of the low-voltage power distribution network area, and input power information and output power information of the hybrid power distribution transformer module; the power controller is used for obtaining power reference values from the control instruction values, controlling power absorbed in the power distribution network area according to the power reference values, and coordinating distributed power generation power in the area; the low-voltage direct current bus voltage controller is used for obtaining direct current voltage reference values from the control instruction values, and controlling low-voltage direct current bus voltage output by a direct current bus capacitor of a power quality control unit to be equal to the direct current voltage reference values; and the voltage compensation output controller is used for obtaining alternating current voltage reference values from the control instruction values after the decentralized coordination control module detects low-voltage alternating current distribution bus drop, and controlling low-voltage alternating current compensation voltage output by a three-phase AC / DC converter of the power quality control unit to be equal to the alternating current voltage reference values. The hybrid power distribution transformer module includes a multi-winding transformer unit, a filter inductor unit and a power quality control unit.

2. The control system of a cluster of hybrid distribution transformers of claim 1, wherein, The multi-winding transformer unit is used for converting high-voltage alternating current into low-voltage alternating current and providing power for the power quality control unit. The power quality control unit is used for providing the low-voltage direct current bus output port and voltage compensation function for the hybrid power distribution transformer module. ​ 3. The control system of a cluster of hybrid distribution transformers according to claim 2, characterized in that, The multi-winding transformer unit comprises three-phase windings, each phase winding comprises a first winding, a second winding and a third winding, the filter inductance unit comprises three filter inductances, the first winding is connected to the primary winding of the high-voltage AC bus, the second winding is connected to the secondary winding of the low-voltage AC bus and serves as the low-voltage AC bus output port of the hybrid distribution transformer module; the three third windings are connected to the power quality control unit in series with the three filter inductances one by one.

4. The control system of a cluster of hybrid distribution transformers of claim 3, wherein, The power quality control unit comprises a three-phase AC / DC converter for converting AC to DC, a three-phase DC / AC converter for converting DC to AC and a DC bus capacitor; the three-phase AC terminals of the three-phase AC / DC converter are connected to the three third windings of the multi-winding transformer unit one by one; the three-phase AC terminals of the three-phase DC / AC converter are connected to the first terminals of the three second windings of the multi-winding transformer unit one by one; and the DC bus capacitor provides the low-voltage DC bus output port of the hybrid distribution transformer module.

5. The control system of a cluster of hybrid distribution transformers of claim 3, wherein, The cluster instruction module is configured to: distribute the power imbalance of the hybrid distribution transformer module in the cluster by using a consensus algorithm, and calculate the control instruction value of each decentralized coordination control module in the cluster based on the power imbalance of the hybrid distribution transformer.

6. A method of operating a control system of a cluster of hybrid distribution transformers according to any one of claims 1 to 5, characterized in that, The cluster instruction module is configured to: receive an external scheduling instruction and low-voltage distribution network cell information, calculate the control instruction value of each decentralized coordination control module in the cluster according to the external scheduling instruction and the distribution network cell information, and send the control instruction value to the corresponding decentralized coordination control module; the decentralized coordination control module controls the system to enter a normal operation mode or a voltage drop mode according to the corresponding control instruction value, so as to coordinate the output port of the hybrid distribution transformer module and compensate the voltage when the low-voltage AC bus drops, wherein the output port of the hybrid distribution transformer module comprises a low-voltage AC bus output port and a low-voltage DC bus output port.

7. The method of operation of claim 6, wherein, The decentralized coordination control module controls the system to enter a normal operation mode according to the corresponding control instruction value, comprising: when it is determined that the low-voltage AC bus voltage has not dropped, adjusting the power absorbed by the low-voltage distribution cell according to the control instruction value received from the cluster instruction module, the low-voltage DC bus voltage and the low-voltage AC bus frequency, by using the droop control method through the power controller and the low-voltage DC bus voltage controller; adjusting the output of the distributed power supply in the low-voltage distribution network according to the AC frequency of the low-voltage AC bus or the DC bus voltage of the low-voltage DC bus by using the power controller and the power controller of the distributed power supply, according to the control instruction value received from the cluster instruction module.

8. The method of operating of claim 7, wherein, The decentralized coordination control module controls the system to enter a voltage drop mode according to the corresponding control instruction value, comprising: After detecting the voltage drop of the low-voltage AC distribution bus, the power quality control module outputs compensation voltage under the control of the voltage compensation output controller to compensate the voltage of the low-voltage AC distribution bus.

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