Active Voltage Support Method, Device, Equipment and Medium for Network-Forming Distributed Energy Storage

Abstract

The present invention relates to a method, device, equipment and medium for the active voltage support of a network-forming distributed energy storage. The method includes: obtaining the reactance and resistance of a distribution line; judging whether there is a voltage over-limit situation according to the voltage at the access point of the network-forming energy storage; if there is a voltage over-limit situation, calculating the required increase in active power output and the required increase in reactive power output for regulating the voltage of the energy storage converter according to the line voltage drop formula and the relationship between the reactance and resistance of the distribution line; superimposing the obtained increase in active power output and the increase in reactive power output on the original active power set value and reactive power set value of the network-forming energy storage converter to obtain new active power set values and reactive power set values, and controlling the active frequency and reactive voltage based on the new active power set values and reactive power set values. The present invention can effectively improve the power quality of the distribution network substation area.

Description

Technical Field

[0001] The present invention relates to the technical field of off-grid and grid-connected control, and particularly to a method, device, equipment and medium for active voltage support of a network-forming distributed energy storage. Background Art

[0002] Distributed photovoltaics have characteristics such as strong intermittency, volatility, and uncertainty. Their large-scale access to the distribution network easily leads to the situation that the voltage in the photovoltaic substation area exceeds the upper limit during the day and the lower limit at night, seriously affecting the power supply quality. It requires two-way adjustment on the power supply side and the load side, posing new requirements for high flexibility in power and electricity balance in the distribution network under the new power system, and increasing the urgent need for energy storage on the distribution network side. On the other hand, in traditional power grids, due to the presence of a large number of synchronous generators with actual moment of inertia to support the power grid, the system has sufficient rotational inertia and usually a strong power grid. With the large-scale access of power electronic devices such as electric vehicle chargers and distributed new energy into the distribution network, and the continuous increase in the penetration rate of power electronic devices, synchronous generators are gradually withdrawn from the power system, causing the power system to gradually transform from a high-inertia strong power grid to a low-inertia weak power grid. Currently, all distribution network converters adopt a grid-following control mode, which is essentially a current source and relies on the grid voltage and frequency to achieve synchronization with the grid. Compared with synchronous generators under traditional power grids, its response speed is relatively fast, but it lacks moment of inertia. When a disturbance occurs in the distribution network, it is difficult for the grid-following converter to provide necessary inertia, frequency, and voltage support. In particular, when the future new power system consists of a higher proportion of power electronic converters, if all converters adopt grid-following control, the power system will lack inertia extremely and be unable to support the grid voltage and frequency, and the system will not be able to operate safely and stably. The network-forming control, by drawing on the physical mechanism and control method of synchronous generators, shapes the converter into an external characteristic of a voltage source, and can construct the voltage amplitude and phase of the AC side by itself through a power synchronization control mechanism without relying on an external AC system, providing voltage and frequency support for the power grid. "Network-forming + energy storage" is to supplement the network-forming converter with an energy storage medium, which can suppress the power fluctuation of new energy power generation, reduce the peak shaving pressure of the power grid, improve the acceptance level of the distribution network for new energy, and meet the power balance requirements of the new power system on multiple time scales. At the same time, it can provide virtual inertia and damping for the system, enabling the energy storage system to have the characteristics of a synchronous generator or similar to a synchronous generator, providing voltage source support throughout the process of power grid disturbance, improving the inertia and damping characteristics of the power grid, and enhancing the stability of the distribution network under high penetration of new energy.

[0003] In the distribution network substation area, the coverage is large and the power supply lines are long, which easily leads to low voltage at the end of the substation area. At the same time, the large-scale access of distributed new energy to the distribution network results in great pressure on the local consumption of new energy and imbalance between power sources and loads, which will further exacerbate the voltage and power quality problems in the distribution network substation area. In response to the above problems, common solutions such as the capacity expansion and transformation of distribution transformers, large-scale transformation of low-voltage lines, and reduction of low-voltage power supply scope have problems of high investment cost and long construction period. Equipping with a grid-following energy storage can solve the low power quality problem in the distribution network substation area to a certain extent, but it cannot solve the problem of low inertia in the distribution network under the high penetration rate of new energy and power electronic devices. To comprehensively solve the above problems, it is urgent to study the application of grid-forming energy storage technology in the distribution network, utilize the active support ability of grid-forming energy storage, strengthen the voltage support ability and frequency response ability of the distribution network, enhance the power source support effect in the weak links of the distribution network, and at the same time, combined with the impedance characteristics of the distribution network substation area, study the method of grid-forming energy storage to improve the power quality of the distribution substation area, so as to enhance the carrying capacity and local consumption capacity of the distribution substation area for distributed power sources.

[0004] The existing public patent document CN118487293A discloses a droop control method for a grid-forming photovoltaic inverter. This method calculates the active power by sampling the voltage and current at the point of common coupling, and subtracts it from the given value to calculate the angular frequency difference according to the droop characteristic , adds it to the rated value , and outputs . Through the integral link, the phase angle of the voltage command value can be obtained. Similarly, through the reactive power-voltage droop characteristic, the voltage command value is obtained. The existing public patent document CN118214071A discloses a machine-side control method for a VSG grid-forming system. This method calculates the active power and reactive power by sampling the voltage and current at the point of common coupling, subtracts the active power from the given value , and then obtains the angular frequency difference through the damping inertia link, adds it to the rated value , and outputs . Through the integral link, the phase angle of the voltage command value is obtained. Similarly, subtracts the reactive power from the given value to obtain the reactive power difference, adds it to the reactive voltage compensation value obtained through the reactive power-voltage droop characteristic, and then passes through an integral regulator to obtain the voltage amplitude command value.

[0005] The above grid-forming control method is only applicable to the case where the line reactance is much greater than the line resistance Under a large power grid, the low-voltage problem of the system is solved by increasing the reactive power output according to the deviation of the converter output voltage from the reference value through the reactive voltage link. However, in the distribution network, the line reactance cannot meet the condition of being much greater than the line resistance. Therefore, only increasing the reactive power output cannot effectively improve the low-voltage problem of the system. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a method for active voltage support of a network-forming distributed energy storage, which can effectively improve the power quality of the distribution network substation area.

[0007] The technical solution adopted by the present invention to solve its technical problems is: to provide a method for active voltage support of a network-forming distributed energy storage, including the following steps:

[0008] Obtain the reactance and resistance of the distribution line;

[0009] Judge whether there is a voltage over-limit situation according to the voltage at the access point of the network-forming energy storage;

[0010] If there is a voltage over-limit situation, calculate the required increase in active power output and the required increase in reactive power output for regulating the voltage energy storage converter according to the line voltage drop formula, the output voltage of the low-voltage side of the distribution network transformer, and the relationship between the reactance and resistance of the distribution line;

[0011] Superimpose the obtained increase in active power output and the increase in reactive power output on the original active power reference value and reactive power reference value of the network-forming energy storage converter to obtain new active power reference value and reactive power reference value, and control the active frequency and reactive voltage based on the new active power reference value and reactive power reference value.

[0012] The judgment of whether there is a voltage over-limit situation according to the voltage at the access point of the network-forming energy storage specifically includes:

[0013] Compare the voltage at the access point of the network-forming energy storage with the upper voltage limit threshold voltage;

[0014] If the voltage at the access point of the network-forming energy storage is greater than the upper voltage limit threshold voltage, it is determined that there is a situation of over-upper voltage limit;

[0015] If the voltage at the access point of the network-forming energy storage is less than the upper voltage limit threshold voltage, compare the voltage at the access point of the network-forming energy storage with the lower voltage limit threshold voltage;

[0016] If the voltage at the access point of the network-forming energy storage is less than the lower voltage limit threshold voltage, it is determined that there is a situation of over-lower voltage limit.

[0017] The calculation of the increase in active output and reactive output required for regulating the voltage storage converter according to the line voltage drop formula, the output voltage on the low-voltage side of the distribution network transformer, and the relationship between the reactance and resistance of the distribution line specifically includes:

[0018] Determining whether a quotient of a reactance and a resistance of the power distribution line is greater than or equal to a first threshold;

[0019] If the quotient of the reactance and resistance of the distribution line is greater than or equal to a first threshold, voltage management is performed only by generating reactive power;

[0020] If the quotient of the reactance and the resistance of the power distribution line is less than the first threshold, determining whether the quotient of the reactance and the resistance of the power distribution line is less than or equal to the second threshold;

[0021] If the quotient of the reactance and resistance of the distribution line is less than or equal to a second threshold, voltage management is performed only by generating active power;

[0022] If the quotient of the reactance and resistance of the distribution line is greater than a second threshold, voltage management is performed by adopting a method of jointly supporting the voltage with active power and reactive power;

[0023] The first threshold is greater than the second threshold.

[0024] When voltage management is performed only by generating reactive power, the increase in active power output is zero, and the increase in reactive power output is: ,in, is the increase in reactive output, is the voltage regulation amount, expressed as: , is the voltage at the access point of the grid-type energy storage, is the voltage lower threshold voltage, is the upper voltage threshold voltage, is the output voltage of the low voltage side of the distribution network transformer, is the reactance of the distribution line.

[0025] When voltage management is performed only by generating active power, the increase in reactive power output is zero, and the increase in active power output is: ,in, is the increase in active output, is the voltage regulation amount, expressed as: , is the voltage at the access point of the grid-type energy storage, is the voltage lower threshold voltage, is the upper voltage threshold voltage, is the output voltage of the low voltage side of the distribution network transformer, is the resistance of the distribution line.

[0026] When the voltage is managed by adopting the method of jointly supporting the voltage with active power and reactive power, the increase in active power output is: , the reactive output increase is: ,in, is the increase in active output, is the voltage regulation amount, expressed as: , is the voltage at the access point of the grid-type energy storage, is the voltage lower threshold voltage, is the upper voltage threshold voltage, is the output voltage of the low voltage side of the distribution network transformer, is the resistance of the distribution line, is the reactance of the distribution line, Increase in reactive output.

[0027] Before the active frequency and reactive voltage are controlled based on the new active power given value and reactive power given value, the method further includes:

[0028] Calculating the total system output power according to the new active power given value and the reactive power given value, and determining whether the total system output power exceeds the total power threshold;

[0029] If the total power output of the system exceeds the total power threshold, the new reactive power given value is adjusted to: ,in, is the new reactive power given value after adjustment, is the new active power given value, S N is the total power threshold.

[0030] The technical solution adopted by the present invention to solve the technical problem is: to provide a grid-type distributed energy storage active voltage support device, comprising:

[0031] An acquisition module, used for acquiring reactance and resistance of a distribution line;

[0032] A judgment module, used to judge whether there is a voltage over-limit situation according to the voltage of the grid-type energy storage access point;

[0033] A calculation module is used to calculate the increase in active output and reactive output required for regulating the voltage storage converter according to the line voltage drop formula, the output voltage on the low-voltage side of the distribution network transformer, and the relationship between the reactance and resistance of the distribution line when there is a voltage over-limit situation;

[0034] The control module is used to superimpose the obtained active output increase and reactive output increase with the original active power set value and reactive power set value of the grid-type energy storage converter to obtain new active power set value and reactive power set value, and control the active frequency and reactive voltage based on the new active power set value and reactive power set value.

[0035] The technical solution adopted by the present invention to solve its technical problem is: to provide an electronic device, including a memory, a processor and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the above-mentioned grid-type distributed energy storage active voltage support method when executing the computer program.

[0036] The technical solution adopted by the present invention to solve its technical problem is: providing a computer-readable storage medium on which a computer program is stored, and when the computer program is executed by a processor, the steps of the above-mentioned grid-type distributed energy storage active voltage support method are implemented.

[0037] Beneficial Effects

[0038] Due to the adoption of the above-mentioned technical scheme, the present invention has the following advantages and positive effects compared with the prior art: the present invention calculates the voltage drop of the distribution network terminal line and the impedance characteristics of the line, distributes the active and reactive power output of the grid-forming energy storage through an optimization algorithm, enhances the support and control of the voltage at the terminal of the distribution network, and effectively improves the power quality of the distribution network substation. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a control block diagram of a grid-type energy storage in the first embodiment of the present invention;

[0040] Figure 2 Flow chart of the grid-type distributed energy storage active voltage support method according to the first embodiment of the present invention;

[0041] Figure 3 This is a simulation result diagram of low voltage management by grid-type energy storage control based on droop control in the prior art;

[0042] Figure 4 This is a simulation result diagram of low voltage control by grid-type energy storage based on traditional VSG in the existing technology;

[0043] Figure 5 This is a diagram showing the simulation results of low voltage management by grid-type energy storage control after adopting the first embodiment of the present invention. DETAILED DESCRIPTION

[0044] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0045] The first embodiment of the present invention relates to a method for active voltage support of a grid-type distributed energy storage. The method is based on traditional grid-type distributed energy storage control, takes into account the impedance characteristics of the distribution network, and reasonably allocates the command values ​​of the active and reactive power of the grid-type distributed energy storage control to participate in voltage regulation according to the impedance characteristics of the distribution network and the voltage to be adjusted.

[0046] Figure 1 This is a control block diagram of the grid-type distributed energy storage in this implementation. The grid-type distributed energy storage in this implementation needs to meet the energy storage charge state constraints. To prevent overcharging and over-discharging of energy storage, the energy storage charge state should not exceed the upper and lower limits. Therefore, the energy storage charge state constraints are as follows:

[0047] ;

[0048] The energy storage charging and discharging power constraints are as follows:

[0049] ;

[0050] in, is the lower limit of the charge state of grid-type distributed energy storage. is the upper limit of the state of charge of the grid-type distributed energy storage, for The state of charge of the grid-connected distributed energy storage at all times; The rated capacity of the grid-type distributed energy storage; for The output power of the grid-connected distributed energy storage at all times.

[0051] like Figure 2 As shown, the grid-type distributed energy storage active voltage support method of this embodiment specifically includes the following steps:

[0052] Step 1: Obtain the reactance of the distribution line and resistor .

[0053] Step 2: Based on the voltage of the grid-type energy storage access point Determine whether the voltage exceeds the limit, specifically:

[0054] The grid-type energy storage access point voltage The upper threshold voltage Make comparisons;

[0055] If the grid-type energy storage access point voltage Greater than the upper voltage threshold voltage , it is determined that the voltage exceeds the upper limit;

[0056] If the grid-type energy storage access point voltage Less than the upper voltage threshold voltage , then the grid-type energy storage access point voltage The voltage lower threshold voltage Make comparisons;

[0057] If the grid-type energy storage access point voltage Less than the lower voltage threshold voltage , it is determined that the voltage exceeds the lower limit.

[0058] Step 3: If there is a voltage over-limit situation, the voltage drop formula is used to calculate the output voltage of the low-voltage side of the distribution network transformer and the reactance of the distribution line. and resistor The relationship between the active output increase and reactive output increase required by the voltage-regulated energy storage converter is calculated. The line voltage drop formula is: ,in, is the voltage drop of the low-voltage distribution network line, that is, the voltage regulation amount, is the active power of the connected load, is the reactive power of the connected load, is the output voltage of the low voltage side of the distribution network transformer.

[0059] This step specifically includes:

[0060] Determine the reactance of the distribution line and resistor Whether the quotient of is greater than or equal to a first threshold, where the first threshold can be set to 2.

[0061] If the reactance of the distribution line and resistor The quotient of is greater than or equal to the first threshold, that is , then the voltage is managed only by generating reactive power; when the voltage is managed only by generating reactive power, the increase in active power output is zero, and the increase in reactive power output is: ,in, is the increase in reactive output, is the voltage regulation amount, expressed as: .

[0062] If the reactance of the distribution line and resistor The quotient of is less than the first threshold, that is , then further determine the reactance of the distribution line and resistor Whether the quotient of is less than a second threshold, where the second threshold can be set to 0.5.

[0063] If the quotient of the reactance and resistance of the distribution line is less than or equal to the second threshold, that is, , then voltage management is performed only by generating active power; when voltage management is performed only by generating active power, the increase in reactive power output is zero, and the increase in active power output is: ,in, It is the increase of active output.

[0064] If the quotient of the reactance and resistance of the distribution line is greater than the second threshold, that is, , the voltage is managed by using active power and reactive power to support the voltage. When the voltage is managed by using active power and reactive power to support the voltage, the increase in active power output is: , the reactive output increase is: .

[0065] It is not difficult to find that this implementation method takes into account the line impedance characteristics and reasonably distributes the output ratio of active power and reactive power according to the line impedance characteristics. In addition, this implementation method only uses the voltage of the energy storage grid connection point to calculate the output ratio of active power and reactive power. and the reactance of the distribution lines and resistor , the active output and reactive output of the grid-type energy storage system required for voltage management can be calculated to achieve power control of the grid-type energy storage system.

[0066] Step 4: Increase the active output and reactive output increase Compared with the original active power setting value of the grid-type energy storage converter and reactive power setpoint Superposition is performed to obtain a new active power given value and reactive power setpoint , and based on the new active power given value and reactive power setpoint Control active frequency and reactive voltage.

[0067] In this step, based on the new active power given value and reactive power setpoint Before controlling the active frequency and reactive voltage, it also includes:

[0068] According to the new active power given value and reactive power setpoint Calculate the total system output power S, which is calculated as follows:

[0069] Determine whether the total output power S of the system exceeds the total power threshold S N ;

[0070] If the total output power S of the system exceeds the total power threshold S N ,Right now , then the new reactive power given value Adjusted to: .

[0071] The following is a comparison of the effects of this embodiment and the prior art.

[0072] Figure 3 The grid voltage is shown when the grid voltage drops by 0.15 pu when the grid energy storage control based on droop control is adopted. , Energy storage grid connection point voltage , Converter output active power and reactive power It can be seen that after the grid voltage drops by 0.15pu, the reactive power output of the converter increases from 0 to 7.5kW, the active power remains unchanged, and the voltage at the energy storage grid connection point is only raised to 333V, with a weak voltage raising effect.

[0073] Figure 4 Demonstrated traditional VSG grid energy storage control, grid voltage when grid voltage drops by 0.15pu , Energy storage grid connection point voltage , Converter output active power and reactive power It can be seen that after the grid voltage drops by 0.15pu, the reactive power output of the converter increases from 0 to 81kW, the active power remains basically unchanged, the voltage at the energy storage grid connection point rises to 370V, the voltage raising effect is more obvious, and the energy storage output capacity is .

[0074] Figure 5 The grid voltage when the grid voltage drops by 0.15 pu is shown. , Energy storage grid connection point voltage , Converter output active power and reactive power It can be seen that after the grid voltage drops by 0.15pu, the reactive power output of the converter increases from 0 to 34kW, the active power increases from 20kW to 72kW, and the voltage at the energy storage grid connection point rises to 386V. The voltage raising effect is optimal, and the energy storage output capacity is , which is smaller than the output capacity of traditional VSG grid energy storage control.

[0075] It is not difficult to find that this implementation method can reduce the number of voltage over-limits in the distribution area and effectively improve the power quality of the distribution network area by reasonably allocating the active power and reactive power output of the grid-type energy storage. Under the same voltage value, this implementation method can effectively reduce the energy storage configuration capacity of the distribution network area, reduce the equipment investment cost, and have better economy; under the same energy storage capacity, this implementation method can expand the scope of voltage management in the distribution area.

[0076] The second embodiment of the present invention relates to a grid-type distributed energy storage active voltage support device, comprising:

[0077] An acquisition module, used for acquiring reactance and resistance of a distribution line;

[0078] A judgment module, used to judge whether there is a voltage over-limit situation according to the voltage of the grid-type energy storage access point;

[0079] A calculation module is used to calculate the increase in active output and reactive output required for regulating the voltage storage converter according to the line voltage drop formula, the output voltage on the low-voltage side of the distribution network transformer, and the relationship between the reactance and resistance of the distribution line when there is a voltage over-limit situation;

[0080] The control module is used to superimpose the obtained active output increase and reactive output increase with the original active power set value and reactive power set value of the grid-type energy storage converter to obtain new active power set value and reactive power set value, and control the active frequency and reactive voltage based on the new active power set value and reactive power set value.

[0081] The judging module comprises:

[0082] A first comparison unit, used for comparing the grid-type energy storage access point voltage with a voltage upper limit threshold voltage;

[0083] A first determining unit is used to determine that the voltage exceeds the upper limit when the voltage of the grid-type energy storage access point is greater than the voltage upper limit threshold voltage;

[0084] A second comparison unit is used to compare the voltage of the grid-type energy storage access point with the voltage lower limit threshold voltage when the voltage of the grid-type energy storage access point is less than the voltage upper limit threshold voltage;

[0085] The second determining unit is used to determine whether the voltage exceeds the lower limit when the voltage at the grid-type energy storage access point is less than the voltage lower limit threshold voltage.

[0086] The calculation module comprises:

[0087] A first judging unit, configured to judge whether a quotient of a reactance and a resistance of the power distribution line is greater than or equal to a first threshold;

[0088] A first management unit, configured to manage voltage only by generating reactive power when the quotient of the reactance and the resistance of the distribution line is greater than or equal to a first threshold;

[0089] A second judgment unit, configured to judge whether the quotient of the reactance and the resistance of the distribution line is less than or equal to a second threshold value when the quotient of the reactance and the resistance of the distribution line is less than the first threshold value;

[0090] A second management unit is used for performing voltage management only by generating active power when the quotient of the reactance and the resistance of the distribution line is less than or equal to a second threshold value;

[0091] A third management unit is used to manage the voltage by using active power and reactive power to jointly support the voltage when the quotient of the reactance and the resistance of the distribution line is greater than a second threshold;

[0092] The first threshold is greater than the second threshold.

[0093] When the first governance unit performs voltage governance only by generating reactive power, the increase in active power output is zero, and the increase in reactive power output is: ,in, is the increase in reactive output, is the voltage regulation amount, expressed as: , is the voltage at the access point of the grid-type energy storage, is the voltage lower threshold voltage, is the upper voltage threshold voltage, is the output voltage of the low voltage side of the distribution network transformer, is the reactance of the distribution line.

[0094] When the second management unit performs voltage management only by generating active power, the increase in reactive power output is zero, and the increase in active power output is: ,in, is the increase in active output, is the voltage regulation amount, expressed as: , is the voltage at the access point of the grid-type energy storage, is the voltage lower threshold voltage, is the upper voltage threshold voltage, is the output voltage of the low voltage side of the distribution network transformer, is the resistance of the distribution line.

[0095] When the third management unit adopts the method of jointly supporting the voltage with active power and reactive power to manage the voltage, the increase in active power output is: , the reactive output increase is: ,in, is the increase in active output, is the voltage regulation amount, expressed as: , is the voltage at the access point of the grid-type energy storage, is the voltage lower threshold voltage, is the upper voltage threshold voltage, is the output voltage of the low voltage side of the distribution network transformer, is the resistance of the distribution line, is the reactance of the distribution line, is the increase in reactive output, is the active power of the connected load.

[0096] The control module comprises:

[0097] A calculation and judgment unit, used to calculate the total system output power according to the new active power given value and the reactive power given value, and to judge whether the total system output power exceeds the total power threshold;

[0098] The adjusting unit is used to adjust the new reactive power given value to: ,in, is the new reactive power given value after adjustment, is the new active power given value, S N is the total power threshold.

[0099] A third embodiment of the present invention relates to an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the grid-type distributed energy storage active voltage support method of the first embodiment when executing the computer program.

[0100] The fourth embodiment of the present invention relates to a computer-readable storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the steps of the grid-type distributed energy storage active voltage support method of the first embodiment are implemented.

[0101] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present application may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage and optical storage, etc.) containing computer-usable program codes.

[0102] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0103] These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer-readable memory produce a manufactured product including an instruction method, which is implemented in the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0104] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0105] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which 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 method for active voltage support of a grid-type distributed energy storage, characterized in that: The following steps are involved: Obtain the reactance and resistance of distribution lines; Determine whether there is a voltage over-limit situation based on the voltage at the grid-type energy storage access point; If there is a voltage over-limit situation, the increase in active output and reactive output required for regulating the voltage storage converter is calculated according to the line voltage drop formula, the output voltage on the low-voltage side of the distribution network transformer, and the relationship between the reactance and resistance of the distribution line, including: Determining whether a quotient of a reactance and a resistance of the power distribution line is greater than or equal to a first threshold; If the quotient of the reactance and resistance of the distribution line is greater than or equal to a first threshold, voltage management is performed only by generating reactive power; If the quotient of the reactance and the resistance of the power distribution line is less than the first threshold, determining whether the quotient of the reactance and the resistance of the power distribution line is less than or equal to the second threshold; If the quotient of the reactance and resistance of the distribution line is less than or equal to a second threshold, voltage management is performed only by generating active power; If the quotient of the reactance and resistance of the distribution line is greater than a second threshold, voltage management is performed by adopting a method of jointly supporting the voltage with active power and reactive power; wherein the first threshold is greater than the second threshold; The obtained active output increase and reactive output increase are superimposed on the original active power set value and reactive power set value of the grid-type energy storage converter to obtain new active power set value and reactive power set value, and the active frequency and reactive voltage are controlled based on the new active power set value and reactive power set value.

2. The grid-type distributed energy storage active voltage support method according to claim 1 is characterized in that: The determining whether there is a voltage over-limit situation according to the voltage of the grid-type energy storage access point specifically includes: Comparing the grid-forming energy storage access point voltage with a voltage upper limit threshold voltage; If the voltage at the grid-type energy storage access point is greater than the voltage upper limit threshold voltage, it is determined that the voltage exceeds the upper limit; if the voltage at the grid-type energy storage access point is less than the voltage upper limit threshold voltage, the voltage at the grid-type energy storage access point is compared with the voltage lower limit threshold voltage; If the voltage of the grid-type energy storage access point is less than the voltage lower limit threshold voltage, it is determined that the voltage exceeds the lower limit.

3. The grid-type distributed energy storage active voltage support method according to claim 1 is characterized in that: When voltage management is performed only by generating reactive power, the increase in active power output is zero, and the increase in reactive power output is: Among them, Q add is the reactive output increase, ΔU is the voltage regulation, expressed as: ΔU = U VL,d / U VL,u -U pcc , U pcc is the grid-type energy storage access point voltage, U VL,d is the voltage lower threshold voltage, U VL,u is the voltage upper limit threshold voltage, U is the output voltage on the low voltage side of the distribution network transformer, and X is the reactance of the distribution line.

4. The grid-type distributed energy storage active voltage support method according to claim 1 is characterized in that: When voltage management is performed only by generating active power, the increase in reactive power output is zero, and the increase in active power output is: Among them, P add is the increase in active output, ΔU is the voltage regulation, expressed as: ΔU = U VL,d / U VL,u -U pcc , U pcc is the grid-type energy storage access point voltage, U VL,d is the voltage lower threshold voltage, U VL,u is the voltage upper limit threshold voltage, U is the output voltage on the low voltage side of the distribution network transformer, and R is the resistance of the distribution line.

5. The grid-type distributed energy storage active voltage support method according to claim 1, characterized in that: When the voltage is managed by adopting the method of jointly supporting the voltage with active power and reactive power, the increase in active power output is: The reactive output increase is: Among them, P add is the increase in active output, ΔU is the voltage regulation, expressed as: ΔU = U VL,d / U VL,u -U pcc , U pcc is the grid-type energy storage access point voltage, U VL,d is the voltage lower threshold voltage, U VL,u is the voltage upper limit threshold voltage, U is the output voltage of the low voltage side of the distribution network transformer, R is the resistance of the distribution line, X is the reactance of the distribution line, Q add Increase in reactive output.

6. The grid-type distributed energy storage active voltage support method according to claim 1, characterized in that: Before the active frequency and reactive voltage are controlled based on the new active power given value and reactive power given value, the method further includes: Calculating the total system output power according to the new active power given value and the reactive power given value, and determining whether the total system output power exceeds the total power threshold; If the total power output of the system exceeds the total power threshold, the new reactive power given value is adjusted to: Among them, Q ref is the new reactive power given value after adjustment, P ref is the new active power given value, S N is the total power threshold.

7. A grid-type distributed energy storage active voltage support device, characterized in that: include: An acquisition module, used for acquiring reactance and resistance of a distribution line; A judgment module, used to judge whether there is a voltage over-limit situation according to the voltage of the grid-type energy storage access point; A calculation module is used to calculate the increase in active output and reactive output required for regulating the voltage storage converter according to the line voltage drop formula, the output voltage on the low-voltage side of the distribution network transformer, and the relationship between the reactance and resistance of the distribution line when the voltage exceeds the limit; The calculation module comprises: A first judging unit, configured to judge whether a quotient of a reactance and a resistance of the power distribution line is greater than or equal to a first threshold; A first management unit, configured to manage voltage only by generating reactive power when the quotient of the reactance and the resistance of the distribution line is greater than or equal to a first threshold; A second judgment unit, configured to judge whether the quotient of the reactance and the resistance of the distribution line is less than or equal to a second threshold value when the quotient of the reactance and the resistance of the distribution line is less than the first threshold value; A second management unit is used for performing voltage management only by generating active power when the quotient of the reactance and the resistance of the distribution line is less than or equal to a second threshold value; A third management unit is used to manage the voltage by using active power and reactive power to jointly support the voltage when the quotient of the reactance and the resistance of the distribution line is greater than a second threshold; Among them, the first threshold is greater than the second threshold The control module is used to superimpose the obtained active output increase and reactive output increase with the original active power set value and reactive power set value of the grid-type energy storage converter to obtain new active power set value and reactive power set value, and control the active frequency and reactive voltage based on the new active power set value and reactive power set value.

8. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the computer program, the steps of the grid-type distributed energy storage active voltage support method as described in any one of claims 1-6 are implemented.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the grid-type distributed energy storage active voltage support method as described in any one of claims 1-6 are implemented.

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