Micro-power distribution cooperative voltage reactive power support control system and micro-power distribution cooperative voltage reactive power support control method

Abstract

The invention discloses a distribution-micro cooperative voltage reactive power support control system and method, and the system comprises a distribution-micro cooperative control center, a main controller, and a plurality of sub micro grids and slave controllers, and the distribution-micro cooperative control center, the main controller and the plurality of slave controllers carry out information transmission through an electric power communication line or a wireless mode. The distribution-micro cooperative control center is used for coordinating the control target of the whole distribution line from the system level and issuing the control target to the main controller; the main controller is used for being responsible for power distribution-micro cooperative control center information interaction, micro-grid group controllable power resource aggregation and micro-grid group cooperative control strategy making, and coordinating a plurality of sub micro-grids to carry out voltage reactive power cooperative control for a power distribution line area. And the plurality of slave controllers serve as micro-grid monitoring and energy management units and are used for being responsible for operation control and energy scheduling of the plurality of sub-micro-grids and responding to the control requirements of the main controller on the distribution line level.

Description

Technical Field

[0001] The present invention relates to the field of distribution and micro-cooperation technology, and in particular to a distribution and micro-cooperation voltage reactive support control system and method. Background Art

[0002] Microgrids have the characteristics of strong coupling with the power grid in energy and weak coupling in operation control. Microgrids can alleviate the pressure on large power grid construction, promote distributed energy construction, improve new energy consumption, and optimize innovative profit models. Grid-connected microgrids require internal source-grid-load coordinated control as a flexible production consumer (prosumer). Some charging pile manufacturers build charging microgrids and connect to the power grid through their charging services. The control mode of a large number of connected microgrids is decentralized and sporadic. The access of multiple microgrids may cause the voltage of the distribution network to increase and the power quality to deteriorate. A multi-microgrid coordinated control mechanism is needed to improve the frequency and voltage support capabilities of microgrids for large power grids, so as to better serve the goals of carbon reduction and new energy consumption.

[0003] For low-voltage microgrids, they are connected to the 10kV distribution network feeder through distribution transformers. When multiple microgrids are connected, simply using the power factor to constrain the distribution network access gateway requirements is not conducive to ensuring the voltage level and fine-tuning of the distribution line, and is likely to deteriorate the voltage quality of the distribution line and affect power supply reliability. Summary of the invention

[0004] In order to overcome the deficiencies in the prior art, the present invention provides a distribution-micro collaborative voltage reactive support control system and method, which can fully utilize the reactive regulation resources of adjustable distributed energy and energy storage in the microgrid when multiple microgrids are connected to the distribution network, provide the voltage support capability of the distribution network, enhance the voltage management level of the distribution line, and improve the power supply reliability.

[0005] In order to achieve the above-mentioned invention object, the technical solution adopted to solve the technical problem is as follows: The present invention discloses a distribution-micro-cooperative voltage and reactive power support control system, comprising a distribution-micro-cooperative control center, a main controller, and a plurality of sub-micro-grids and slave controllers, wherein: The distribution-micro-cooperative control center, the main controller and the plurality of slave controllers use power communication lines or wireless methods to transmit information; The distribution-micro-cooperative control center is used to coordinate the control target of the entire distribution line from the system level and send this control target to the main controller; The main controller is responsible for information interaction between the distribution-micro-cooperative control center, aggregation of controllable power resources of the micro-grid group, formulation of the micro-grid group cooperative control strategy, and coordination of multiple sub-micro-grids to carry out voltage and reactive power cooperative control for the distribution line area; The plurality of slave controllers serve as microgrid monitoring and energy management units, and are responsible for the operation control and energy scheduling of the plurality of sub-microgrids, while responding to the control requirements of the master controller at the distribution line level.

[0006] Furthermore, it also includes a substation, and the distribution line extends the power supply path outward from the power supply point of the substation, and multiple sub-microgrids are connected to the distribution line through grid connection points U1, U2, U3, U4, U5, and U6.

[0007] Furthermore, the main controller communicates with the distribution line terminal, supports the collection of voltage and current data of the distribution line switches S0, S1, S2, S3, S4, S5, and S6, supports communication with each sub-microgrid slave controller, and obtains the operating status information of the sub-microgrid. The specific functions are as follows: (1) Information interaction between the distribution and microgrid collaborative control center: The interaction includes reporting the real-time operation status of the microgrid group and the controllable power resources; at the same time, receiving the power control instructions of the distribution and microgrid collaborative control center and the measurement information of the line voltage / current / frequency / power at each microgrid connection point; (2) Based on the control requirements of the distribution-microgrid collaborative control center, the master controller formulates the operation control instructions for each microgrid according to the real-time operation status of the microgrid, and completes the issuance of the instructions to each slave controller to meet the control objectives of distribution-microgrid collaborative control, inter-group mutual assistance operation and optimization of controllable resources.

[0008] Furthermore, the slave controller, in addition to completing the operation control and energy management functions of the microgrid, is also responsible for information exchange with the master controller, controllable power resource calculation, and execution of the master controller's delivery strategy. Its functions are as follows: (1) Information interaction with the main controller: The interaction includes reporting the real-time operating status and controllable power resources of the microgrid to which it belongs; and receiving power control instructions from the main controller; (2) Execute micro-power control instructions: Based on the control requirements of the main controller and the real-time operation status of the photovoltaic-storage-charging-loading system in the microgrid, control each controllable resource, monitor the control results, and feed them back to the main controller.

[0009] The present invention further discloses a method for controlling a power distribution and micro-cooperative voltage reactive support, which is controlled by using the power distribution and micro-cooperative voltage reactive support control system, and includes the following steps: Step 1: The distribution-micro-cooperative control center monitors the operation of the distribution line. When it detects that the voltage of the distribution line exceeds the limit, it notifies the main controller to start voltage limit regulation control; Step 2: The master controller notifies the slave controller to perform reactive power control of the microgrid based on the calculated voltage sensitivity matrix and the controllable power resource status uploaded by the slave controller; Step 3: After receiving the control instruction from the main controller, the slave controller carries out the dispatch and adjustment of the reactive resources inside the microgrid based on the operation status of the microgrid; Step 4: If the distribution-micro collaborative control center monitors that the distribution line voltage has returned to normal, notify the main controller to lock the voltage over-limit regulation control; otherwise, continue with step 1.

[0010] Furthermore, the step 2 includes the following contents: For a 10kV distribution network feeder that radiates from the power source point, the distribution network voltage monitored by the main controller is a series of voltage values, which is a state variable sequence ~ ; The control variable that can be controlled is the reactive power sequence at the PCC point of each sub-microgrid ~ 6, so it can be written in the form of voltage-reactive sensitivity matrix as follows: Among them, the voltage-reactive sensitivity matrix consists of N×N matrix elements, N represents the number of nodes in the distribution line, and the i-th row represents the partial derivative of the voltage of the i-th node with respect to the reactive power of all nodes (1 to N), such as the second row element of the matrix , , …, They respectively represent the partial derivatives of the second node voltage U2 with respect to the first node reactive power Q1, the second node reactive power Q2, ..., the sixth node reactive power.

[0011] Furthermore, if the elements of this sensitivity matrix are already known, the reactive power of the microgrid PCC point with the greatest sensitivity is adjusted. The sensitivity calculation of the radial distribution line can be simplified as follows: The voltage at the infinite power supply point U0 can be considered as the rated voltage. Therefore, the voltage at point U1 can be expressed as: U1=U0-(P 1，2 *R1+Q 1，2 *X1) / U1 (1) in, is the active power on line L1; is the reactive power on line L1; is the resistance of L1; is the reactance of L1; When only the reactive power of the export of sub-microgrid 1 changes, the change of Q1 ΔQ1 is 1，2 Therefore, the derivative of equation (1) with respect to Q1 is: Similarly, since it is a radial line, the changes of Q2, Q3, Q4, Q5, and Q6 are also reflected by Q1，2 's changes to reflect this, therefore: For U2: U2=U1-(P 2，3 *R2+Q 2，3 *X2) / U2 (2) in, is the active power on line L2; is the reactive power on line L2; is the resistance of L2; is the reactance of L2; Substituting formula (1) into the equation, we get: U2= U0-(P 1，2 *R1+Q 1，2 *X1) / U1-(P 2，3 *R1+Q 2，3 *X2) / U2(3) Similarly, when only the reactive power at the outlet of sub-microgrid 2 changes, the change of Q2 ΔQ2 is calculated through Q 2，3 and Q 1，2 Reflect, therefore: Since the radiation line ΔQ1 affects P 2，3 and Q 2，3 No influence, the partial derivative of Q1 is obtained from formula (2): = = Due to the radiation line, the influence of ΔQ2 on U2 is calculated by formula (2) through the influence of ΔQ2 on U1. and Q 2，3 Therefore, the partial derivative of Q2 is obtained from formula (2): Due to the radial line, the influence of reactive power changes ΔQ3, ΔQ4, ΔQ5, and ΔQ6 of each node behind node U2 on U2 is equal to the above formula: Similarly, the same reasoning is used for node U3: in, is the reactance of L3; Similarly, the same reasoning is used for node U4: in, is the reactance of L4; Similarly, the same reasoning is used for node U5: in, is the reactance of L5; Similarly, the same reasoning is used for node U6: in, is the reactance of L6; In the above formula, the denominator uses the rated voltage, which can conveniently use the line reactance value to calculate the voltage-reactive sensitivity matrix of each node of the line. After this sensitivity matrix is ​​calculated, its value is used as the constant of the main controller algorithm. According to this matrix, the impact of reactive power changes at each node on the voltage of other nodes can be calculated: When the voltage at point U2 exceeds the limit by +ΔU2, the reactive power change required at point U1 is ΔQ1 to offset the voltage exceeding the limit. .

[0012] Furthermore, considering that reactive power is easy to be adjusted nearby to avoid loss, if the sensitivity coefficients are the same, the adjustment is done nearby. The process of the main controller looking for an adjustable sub-microgrid is as follows: (1) When a node voltage exceeds the limit, the most sensitive reactive power regulation nodes are sorted according to the voltage-reactive power sensitivity matrix; (2) Starting from the most sensitive node, confirm in turn whether the node sub-microgrid has reactive power regulation capacity. If so, send a reactive power regulation instruction ΔQ to the slave controller of this node; the slave controller confirms to perform reactive power regulation and informs the master controller of its reactive power regulation resource status; (3) If the main controller receives a message that reactive power resources are exhausted, it will start to send reactive power regulation instructions from the secondary sensitive node to notify this sub-microgrid to adjust. This process continues until there is no voltage exceeding the limit node or all sub-microgrids have exhausted their regulation capacity, at which time an alarm message is given.

[0013] Furthermore, in step 3, the control process from the controller is as follows: (1) According to the reactive power control resources in the microgrid, sorting-aggregation calculation is performed to sort the controllable reactive power resources; based on this, the aggregated reactive power controllability of the microgrid is obtained and reported to the main controller; (2) If the voltage at the PCC point exceeds the limit, local reactive power voltage control is carried out until the voltage meets the requirement or the reactive power regulation capacity is exhausted; (3) Receive control commands from the main controller and perform reactive power control at the PCC point until the local voltage does not meet the requirements, reaches the target value, or receives a stop control command from the main controller.

[0014] Due to the adoption of the above technical solution, the present invention has the following advantages and positive effects compared with the prior art: 1. Based on the voltage sensitivity matrix of the microgrid access point of the distribution network feeder, the coordinated voltage and reactive power regulation of the distribution network and the microgrid can be carried out, which can make full use of the reactive power regulation resources of the microgrid connected to the distribution network, support the voltage level of the distribution network, make full use of the reactive power regulation resources of the microgrid, and reduce investment; 2. Based on the radial characteristics of the distribution lines and the characteristics of the voltage-reactive sensitivity matrix, the best access point can be quickly determined, and the controller can be used for coordinated control and adjustment; Based on the master controller-slave controller two-layer architecture, the requirements of local voltage regulation of the microgrid and unified coordinated regulation at the 10kV feeder layer are met, the regulation capacity of the microgrid is fully mobilized, and the functional requirements of coordinated voltage regulation control between the distribution and microgrid are realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work. In the drawings: Figure 1 It is a structural diagram of a distribution and micro-cooperative voltage and reactive power support control system of the present invention; Figure 2 It is a flow chart of a method for controlling voltage reactive power support of a power distribution and micro-distribution system according to the present invention; Figure 3 It is a schematic diagram of the radial power distribution line in the present invention; Figure 4 It is a schematic diagram of reactive power regulation of the microgrid in the present invention. DETAILED DESCRIPTION

[0016] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. 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.

[0017] Embodiment 1 like Figure 1 As shown, the present invention discloses a distribution-micro-cooperative voltage and reactive power support control system. The entire distribution-micro-cooperative control system adopts a "master-slave" two-layer control architecture, including a distribution-micro-cooperative control center, a master controller, and a plurality of sub-microgrids and slave controllers, wherein: The distribution-micro-cooperative control center, the main controller and the plurality of slave controllers use power communication lines or wireless methods to transmit information; The distribution-micro-cooperative control center is used to coordinate the control target of the entire distribution line from the system level and send this control target to the main controller; The main controller is responsible for the core control functions such as information interaction between the distribution-micro-cooperative control center, aggregation of controllable power resources of the micro-grid group, formulation of the micro-grid group cooperative control strategy, and coordination of multiple sub-micro-grids to carry out voltage and reactive power cooperative control for the distribution line area; The plurality of slave controllers serve as microgrid monitoring and energy management units, and are responsible for the operation control and energy scheduling of the plurality of sub-microgrids, while responding to the control requirements of the master controller at the distribution line level.

[0018] Furthermore, it also includes a substation, and the distribution line extends the power supply path outward from the power supply point of the substation, and multiple sub-microgrids are connected to the distribution line through the grid connection points U1, U2, U3, U4, U5, and U6. For the scenario where multiple microgrids are connected to the distribution line, the distribution-micro collaborative control system can make full use of the reactive regulation resources of the adjustable distributed energy and energy storage in the microgrid, provide the voltage support capability of the distribution network, and improve the power quality level and power supply reliability of the distribution network.

[0019] Furthermore, the main controller communicates with the distribution line terminal, supports the collection of voltage and current data of the distribution line switches S0, S1, S2, S3, S4, S5, and S6, supports communication with each sub-microgrid slave controller, and obtains the operating status information of the sub-microgrid. The specific functions are as follows: (1) Information interaction between the distribution and microgrid collaborative control center: The interaction includes reporting the real-time operation status of the microgrid group and the controllable power resources; at the same time, receiving the power control instructions of the distribution and microgrid collaborative control center and the measurement information of the line voltage / current / frequency / power at each microgrid connection point; (2) Based on the control requirements of the distribution-microgrid collaborative control center, the master controller formulates the operation control instructions for each microgrid according to the real-time operation status of the microgrid, and completes the issuance of the instructions to each slave controller to meet the control objectives of distribution-microgrid collaborative control, inter-group mutual assistance operation and optimization of controllable resources.

[0020] Furthermore, the slave controller, as the "brain" of the microgrid, is responsible for information exchange with the master controller, controllable power resource calculation, and execution of the master controller's delivery strategy, in addition to completing the operation control and energy management functions of the microgrid. Its functions are as follows: (1) Information interaction with the main controller: The interaction includes reporting the real-time operating status of the microgrid (voltage, frequency, power and other information at the microgrid connection point) and controllable power resources; receiving power control instructions from the main controller; (2) Execute micro-power control instructions: Based on the control requirements of the main controller and the real-time operation status of the photovoltaic-storage-charging-loading system in the microgrid, control each controllable resource, monitor the control results, and feed them back to the main controller.

[0021] Embodiment 2 The microgrid group's support and control of the distribution line voltage level is reflected in the control of the voltage level of each sub-microgrid grid connection point. Since the main controller can collect distribution network-level information for coordinated control of voltage, its role is mainly reflected in coordinating microgrid resources to control the output of voltage regulation resources when the original voltage control cannot meet the requirements. Since wind turbines, photovoltaics and energy storage basically adopt decoupling control of active and reactive power, their reactive power is used as an important voltage support controllable resource for distribution lines.

[0022] According to the radial characteristics of the distribution lines, in this embodiment, based on the sensitivity matrix, the main controller determines the reactive support target value required by the sub-microgrid to eliminate the over-limit according to the pre-set sensitivity matrix, and sends it to the appropriate sub-microgrid (with regulation capability) for regulation and control.

[0023] like Figure 2 As shown, the present invention further discloses a control method for power distribution and micro-cooperative voltage reactive support, which is controlled by using the above-mentioned power distribution and micro-cooperative voltage reactive support control system, including the following steps: Step 1: The distribution-micro-cooperative control center monitors the operation of the distribution line. When it detects that the voltage of the distribution line exceeds the limit, it notifies the main controller to start voltage limit regulation control; Step 2: The master controller notifies the slave controller to perform reactive power control of the microgrid based on the calculated voltage sensitivity matrix and the controllable power resource status uploaded by the slave controller; Step 3: After receiving the control instruction from the main controller, the slave controller carries out the dispatch and adjustment of the reactive resources inside the microgrid based on the operation status of the microgrid; Step 4: If the distribution-micro collaborative control center monitors that the distribution line voltage has returned to normal, notify the main controller to lock the voltage over-limit regulation control; otherwise, continue with step 1.

[0024] Furthermore, the step 2 includes the following contents: For a 10kV distribution network feeder that radiates from the power source point, the distribution network voltage monitored by the main controller is a series of voltage values, which is a state variable sequence ~ ; The control variable that can be controlled is the reactive power sequence at the PCC point of each sub-microgrid ~ 6, so it can be written in the form of voltage-reactive sensitivity matrix as follows: Among them, the voltage-reactive sensitivity matrix consists of N×N matrix elements, N represents the number of nodes in the distribution line, and the i-th row represents the partial derivative of the voltage of the i-th node with respect to the reactive power of all nodes (1 to N), such as the second row element of the matrix , , …, They respectively represent the partial derivatives of the second node voltage U2 with respect to the first node reactive power Q1, the second node reactive power Q2, ..., the sixth node reactive power.

[0025] Furthermore, if the elements of this sensitivity matrix are known, the reactive power of the microgrid PCC point with the greatest sensitivity can be adjusted. Figure 3 As shown in the figure, the sensitivity calculation of radial distribution lines can be simplified as follows: The voltage at the infinite power supply point U0 can be considered as the rated voltage. Therefore, the voltage at point U1 can be expressed as: U1=U0-(P 1，2 *R1+Q 1，2 *X1) / U1 (1) in, is the active power on line L1; is the reactive power on line L1; is the resistance of L1; is the reactance of L1; like Figure 3 As shown in the figure, when only the reactive power of the export of microgrid 1 (MG1) changes, the change of Q1 ΔQ1 is 1，2 Therefore, the derivative of equation (1) with respect to Q1 is: Similarly, since it is a radial line, the changes of Q2, Q3, Q4, Q5, and Q6 are also reflected by Q 1，2 's changes to reflect this, therefore: For U2: U2=U1-(P 2，3 *R2+Q 2，3 *X2) / U2 (2) in, is the active power on line L2; is the reactive power on line L2; is the resistance of L2; is the reactance of L2; Substituting formula (1) into the equation, we get: U2= U0-(P 1，2 *R1+Q 1，2 *X1) / U1-(P 2，3 *R1+Q 2，3 *X2) / U2(3) Similarly, when only the reactive power of the export of microgrid 2 (MG2) changes, the change of Q2 ΔQ2 is 2，3 and Q 1，2 Reflect, therefore: Since the radiation line ΔQ1 affects P 2，3 and Q 2，3No influence, the partial derivative of Q1 is obtained from formula (2): = = Due to the radiation line, the influence of ΔQ2 on U2 is calculated by formula (2) through the influence of ΔQ2 on U1. and Q 2，3 Therefore, the partial derivative of Q2 is obtained from formula (2): Due to the radial line, the influence of reactive power changes ΔQ3, ΔQ4, ΔQ5, and ΔQ6 of each node behind node U2 on U2 is equal to the above formula: Similarly, the same reasoning is used for node U3: in, is the reactance of L3; Similarly, the same reasoning is used for node U4: in, is the reactance of L4; Similarly, the same reasoning is used for node U5: in, is the reactance of L5; Similarly, the same reasoning is used for node U6: in, is the reactance of L6; In the above formula, the denominator uses the rated voltage, which can conveniently use the line reactance value to calculate the voltage-reactive sensitivity matrix of each node of the line. After this sensitivity matrix is ​​calculated, its value is used as the constant of the main controller algorithm. According to this matrix, the impact of reactive power changes at each node on the voltage of other nodes can be calculated: When the voltage at point U2 exceeds the limit by +ΔU2, the reactive power change required at point U1 is ΔQ1 to offset the voltage exceeding the limit. .

[0026] Furthermore, considering that reactive power is easy to be adjusted nearby to avoid loss, if the sensitivity coefficients are the same, the adjustment is done nearby. The process of the main controller looking for an adjustable sub-microgrid is as follows: (1) If a node voltage exceeds the limit (the most serious node) is detected, the most sensitive reactive power regulation nodes are sorted according to the voltage-reactive power sensitivity matrix; (2) Starting from the most sensitive node, confirm in turn whether the node sub-microgrid has reactive power regulation capacity. If so, send a reactive power regulation instruction ΔQ to the slave controller of this node; the slave controller confirms to perform reactive power regulation and informs the master controller of its reactive power regulation resource status; (3) If the main controller receives a message that reactive power resources are exhausted, it will start to send reactive power regulation instructions from the secondary sensitive node to notify this sub-microgrid to adjust. This process continues until there is no voltage exceeding the limit node or all sub-microgrids have exhausted their regulation capacity, at which time an alarm message is given.

[0027] like Figure 1 As shown, if the voltage at the grid connection point U2 of sub-microgrid 2 (or the accessory switch) exceeds the limit, sub-microgrid 2 can no longer adjust the local voltage (such as the reactive power adjustment capacity is exhausted), and other sub-microgrids can be mobilized to provide reactive voltage support to adjust the voltage at U2 to within the qualified range.

[0028] Furthermore, in step 3, the control process from the controller is as follows: (1) According to the reactive control resources in the microgrid, sorting-aggregation calculation is performed (such as Figure 4 The reactive power regulation capability of wind turbines, photovoltaics and energy storage in the microgrid is used to sort the controllable reactive power resources; based on this, the controllable reactive power capability of the microgrid is obtained and reported to the main controller; (2) If the voltage at the PCC point exceeds the limit, local reactive power voltage control is carried out until the voltage meets the requirement or the reactive power regulation capacity is exhausted; (3) Receive control commands from the main controller (increase reactive power or reduce reactive power) and perform reactive power control at the PCC point (at a fixed step size) until the local voltage does not meet the requirements, reaches the target value, or receives a stop control command from the main controller.

[0029] Figure 4 In the microgrid, the resources with reactive power regulation capability include: wind turbines, photovoltaics, and energy storage. The controller algorithm needs to aggregate reactive power regulation resources according to the reactive power control requirements of each device (such as meeting the power factor). The reactive power regulation capability is calculated based on the voltage at the PCC point; if the voltage at the PCC point has reached the upper limit, reactive power cannot be generated. In order to avoid regulation oscillation, reactive power regulation is performed according to a fixed step size (ΔQ), which can be debugged and configured according to the actual regulation effect.

[0030] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A distribution and micro-coordinated voltage and reactive power support control system, characterized in that: It includes a distribution-micro-cooperative control center, a master controller, and several sub-microgrids and slave controllers, among which: The distribution-micro-cooperative control center, the main controller and the plurality of slave controllers use power communication lines or wireless methods to transmit information; The distribution-micro-cooperative control center is used to coordinate the control target of the entire distribution line from the system level and send this control target to the main controller; The main controller is responsible for information interaction between the distribution-micro-cooperative control center, aggregation of controllable power resources of the micro-grid group, formulation of the micro-grid group cooperative control strategy, and coordination of multiple sub-micro-grids to carry out voltage and reactive power cooperative control for the distribution line area; The plurality of slave controllers serve as microgrid monitoring and energy management units, and are responsible for the operation control and energy scheduling of the plurality of sub-microgrids, while responding to the control requirements of the master controller at the distribution line level.

2. A distribution and micro-coordinated voltage and reactive power support control system according to claim 1, characterized in that: It also includes a substation, and the distribution line extends a power supply path outward from the power supply point of the substation, and multiple sub-microgrids are connected to the distribution line through grid connection points U1, U2, U3, U4, U5, and U6.

3. A distribution and micro-coordinated voltage and reactive power support control system according to claim 1, characterized in that: The main controller communicates with the distribution line terminal, supports the collection of voltage and current data of the distribution line switches S0, S1, S2, S3, S4, S5, and S6, supports communication with the slave controllers of each sub-microgrid, and obtains the operating status information of the sub-microgrid. The specific functions are as follows: (1) Information interaction between the distribution and microgrid collaborative control center: The interaction includes reporting the real-time operation status of the microgrid group and the controllable power resources; at the same time, receiving the power control instructions of the distribution and microgrid collaborative control center and the measurement information of the line voltage / current / frequency / power at each microgrid connection point; (2) Based on the control requirements of the distribution-microgrid collaborative control center, the master controller formulates the operation control instructions for each microgrid according to the real-time operation status of the microgrid, and completes the issuance of the instructions to each slave controller to meet the control objectives of distribution-microgrid collaborative control, inter-group mutual assistance operation and optimization of controllable resources.

4. A distribution and micro-coordinated voltage and reactive power support control system according to claim 1, characterized in that: The slave controller, in addition to completing the operation control and energy management functions of the microgrid, is also responsible for information exchange with the master controller, controllable power resource calculation, and execution of the master controller's delivery strategy. Its functions are as follows: (1) Information interaction with the main controller: The interaction includes reporting the real-time operating status and controllable power resources of the microgrid to which it belongs; and receiving power control instructions from the main controller; (2) Execute micro-power control instructions: Based on the control requirements of the main controller and the real-time operation status of the photovoltaic-storage-charging-loading system in the microgrid, control each controllable resource, monitor the control results, and feed them back to the main controller.

5. A method for controlling voltage reactive power support in a coordinated manner between power distribution and micro-distribution, characterized in that: The control is performed by using any one of the above claims 1-4 to coordinate the voltage and reactive power support control system, including the following steps: Step 1: The distribution-micro-cooperative control center monitors the operation of the distribution line. When it detects that the voltage of the distribution line exceeds the limit, it notifies the main controller to start voltage limit regulation control; Step 2: The master controller notifies the slave controller to perform reactive power control of the microgrid based on the calculated voltage sensitivity matrix and the controllable power resource status uploaded by the slave controller; Step 3: After receiving the control instruction from the main controller, the slave controller carries out the dispatch and adjustment of the reactive resources inside the microgrid based on the operation status of the microgrid; Step 4: If the distribution-micro collaborative control center monitors that the distribution line voltage has returned to normal, notify the main controller to lock the voltage over-limit regulation control; otherwise, continue with step 1.

6. A method for controlling voltage and reactive power support in coordination with distribution network according to claim 5, characterized in that: The step 2 includes the following contents: For a 10kV distribution network feeder that radiates from the power source point, the distribution network voltage monitored by the main controller is a series of voltage values, which is a state variable sequence ~ ; The control variable that can be controlled is the reactive power sequence at the PCC point of each sub-microgrid ~ 6, so it can be written in the form of voltage-reactive sensitivity matrix as follows: Among them, the voltage-reactive sensitivity matrix consists of N×N matrix elements, N represents the number of nodes in the distribution line, and the i-th row represents the partial derivative of the voltage of the i-th node with respect to the reactive power of all nodes (1 to N), such as the second row element of the matrix , , …, They respectively represent the partial derivatives of the second node voltage U2 with respect to the first node reactive power Q1, the second node reactive power Q2, ..., the sixth node reactive power.

7. A method for controlling voltage and reactive power support in coordination with distribution network according to claim 6, characterized in that: If the elements of this sensitivity matrix are already known, the reactive power of the PCC point of the microgrid with the greatest sensitivity is adjusted. The sensitivity calculation of the radial distribution line can be simplified as follows: The voltage at the infinite power supply point U0 can be considered as the rated voltage. Therefore, the voltage at point U1 can be expressed as: U1=U0-(P 1，2 *R1+Q 1，2 *X1) / U1(1) in, is the active power on line L1; is the reactive power on line L1; is the resistance of L1; is the reactance of L1; When only the reactive power of the export of sub-microgrid 1 changes, the change of Q1 ΔQ1 is 1，2 Therefore, the derivative of equation (1) with respect to Q1 is: Similarly, since it is a radial line, the changes of Q2, Q3, Q4, Q5, and Q6 are also reflected by Q 1，2 's changes to reflect this, therefore: For U2: <h2 style=";text-align:left;direction:ltr">U2=U1-(P<h2 style=";text-align:left;direction:ltr"> 2，3 <h2 style=";text-align:left;direction:ltr"> *R2+Q<h2 style=";text-align:left;direction:ltr"> 2，3 <h2 style=";text-align:left;direction:ltr"> *X2) / U2 (2) in, is the active power on line L2; is the reactive power on line L2; is the resistance of L2; is the reactance of L2; Substituting formula (1) into the equation, we get: U2= U0-(P 1，2 *R1+Q 1，2 *X1) / U1-(P 2，3 *R1+Q 2，3 *X2) / U2(3) Similarly, when only the reactive power at the outlet of sub-microgrid 2 changes, the change of Q2 ΔQ2 is calculated through Q 2，3 and Q 1，2 Reflect, therefore: Since the radiation line ΔQ1 affects P 2，3 and Q 2，3 No influence, the partial derivative of Q1 is obtained from formula (2): = = Due to the radiation line, the influence of ΔQ2 on U2 is calculated by formula (2) through the influence of ΔQ2 on U1. and Q 2，3 Therefore, the partial derivative of Q2 is obtained from formula (2): Due to the radial line, the influence of reactive power changes ΔQ3, ΔQ4, ΔQ5, and ΔQ6 of each node behind node U2 on U2 is equal to the above formula: Similarly, the same reasoning is used for node U3: in, is the reactance of L3; Similarly, the same reasoning is used for node U4: in, is the reactance of L4; Similarly, the same reasoning is used for node U5: in, is the reactance of L5; Similarly, the same reasoning is used for node U6: in, is the reactance of L6; In the above formula, the denominator uses the rated voltage, which can conveniently use the line reactance value to calculate the voltage-reactive sensitivity matrix of each line node. After this sensitivity matrix is ​​calculated, its value is used as the main controller algorithm constant. According to this matrix, the impact of reactive power changes at each node on the voltage of other nodes can be calculated: When the voltage at point U2 exceeds the limit by +ΔU2, the reactive power change required at point U1 is ΔQ1 to offset the voltage exceeding the limit. 。 8. A method for controlling voltage and reactive power support in coordination with distribution network according to claim 7, characterized in that: At the same time, considering that reactive power is easy to adjust nearby to avoid loss, if the sensitivity coefficient is the same, it is adjusted nearby. The process of the main controller looking for an adjustable sub-microgrid is as follows: (1) When a node voltage exceeds the limit, the most sensitive reactive power regulation nodes are sorted according to the voltage-reactive power sensitivity matrix; (2) Starting from the most sensitive node, confirm in turn whether the node sub-microgrid has reactive power regulation capacity. If so, send a reactive power regulation instruction ΔQ to the slave controller of this node; the slave controller confirms to perform reactive power regulation and informs the master controller of its reactive power regulation resource status; (3) If the main controller receives a message that reactive power resources are exhausted, it will start to send reactive power regulation instructions from the secondary sensitive node to notify this sub-microgrid to adjust. This process continues until there is no voltage exceeding the limit node or all sub-microgrids have exhausted their regulation capacity, at which time an alarm message is given.

9. A method for controlling voltage and reactive power support in coordination with distribution network according to claim 8, characterized in that: In step 3, the control process from the controller is as follows: (1) According to the reactive power control resources in the microgrid, sorting-aggregation calculation is performed to sort the controllable reactive power resources; based on this, the aggregated reactive power controllability of the microgrid is obtained and reported to the main controller; (2) If the voltage at the PCC point exceeds the limit, local reactive power voltage control is carried out until the voltage meets the requirement or the reactive power regulation capacity is exhausted; (3) Receive control commands from the main controller and perform reactive power control at the PCC point until the local voltage does not meet the requirements, reaches the target value, or receives a stop control command from the main controller.

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