Network-formation type energy storage power distribution substation voltage control method based on reactive power negative feedback adaptive regulation of active and reactive power output

Abstract

The application relates to a network-constructing energy storage power distribution area voltage control method based on reactive negative feedback adaptive regulation of active and reactive output, which comprises the following steps: dynamically adjusting a voltage reference value according to an energy storage grid-connected point voltage; calculating a difference value between an actual output value of a reactive power of an energy storage converter and a given value; generating active and reactive output adjustment values under different conditions according to the absolute value of the reactive power difference value and excessive voltage control conditions; and updating the given value of the active and reactive power of the energy storage converter according to the generated output adjustment values. The application can realize effective support control of the terminal voltage of a power distribution network, improve power quality of a power distribution area, and improve power supply capacity.

Description

Technical Field

[0001] This invention relates to the field of energy storage converter control technology, and in particular to a method for managing the voltage of grid-type energy storage distribution substations based on reactive negative feedback adaptive adjustment of active and reactive power output. Background Technology

[0002] Over the past decade, the large-scale integration of distributed renewable energy and other power electronic converter equipment into distribution networks has profoundly changed the structure and operating characteristics of these networks. Distribution networks have transformed from a radial, passive structure to a multi-source mesh structure, and power flow has shifted from a single direction to a complex, variable, bidirectional, or even multidirectional flow. This change has disrupted the original power balance and voltage distribution patterns of the distribution network. Distribution area energy storage, with its four-quadrant power regulation characteristics, can flexibly adapt to different operating conditions and achieve second-level voltage limit mitigation in distribution areas. Traditional distribution area energy storage control is grid-following control, lacking active inertia / frequency support capabilities and unable to support grid voltage and frequency. Grid-based energy storage control, by simulating the operating mechanism of synchronous generators, possesses virtual inertia and damping coefficients, enabling active inertia / frequency support capabilities and adapting to low-inertia new power systems with a high proportion of renewable energy integration. Meanwhile, grid-based energy storage control, through a simulated synchronous generator control method, possesses the external characteristics of a synchronous generator. It can maintain a relatively constant internal potential during transient and subtransient processes, respond to voltage changes with zero delay, and effectively suppress rapid line voltage fluctuations, achieving millisecond-level voltage over-limit suppression. However, grid-based energy storage voltage regulation is differential regulation; relying solely on active voltage regulation through grid control cannot achieve precise voltage control of distribution substations. Furthermore, the line impedance in distribution networks is relatively high, making reactive power regulation alone insufficient and economically inefficient for voltage control. Summary of the Invention

[0003] The technical problem to be solved by this invention is to provide a method for voltage management of grid-type energy storage distribution substations based on reactive negative feedback adaptive adjustment of active and reactive power output, which can effectively support and control the voltage at the end of the distribution network, improve the power quality of the distribution substations, and enhance their power supply capacity.

[0004] The technical solution adopted by this invention to solve its technical problem is: to provide a method for voltage management of grid-type energy storage distribution substations based on reactive power negative feedback adaptive adjustment of active and reactive power output, comprising:

[0005] The voltage reference value is dynamically adjusted based on the voltage at the energy storage grid connection point.

[0006] The reactive power difference is obtained by calculating the difference between the actual output value of the reactive power of the grid-type energy storage converter and the given value under the current voltage reference value.

[0007] When the absolute value of the reactive power difference is less than or equal to the first power setting value, it is determined whether there is excessive voltage regulation. If there is excessive voltage regulation, the waiting flag is set to valid, and the active power adjustment value and reactive power adjustment value are calculated based on the set active power reference adjustment value and line impedance ratio. Otherwise, the waiting flag is set to invalid, and the active power adjustment value and reactive power adjustment value are set to zero.

[0008] When the absolute value of the reactive power difference is greater than the first power setting value, if the voltage at the energy storage grid connection point is greater than the first voltage setting value or less than the second voltage setting value, or if the voltage at the energy storage grid connection point is in the first setting range and the waiting flag is invalid, then the active power output adjustment value and the reactive power output adjustment value are calculated based on the reactive power difference and the line impedance ratio. The first setting range is the range with the first voltage setting value as the upper boundary, the second voltage setting value as the lower boundary, and includes both the first voltage setting value and the second voltage setting value. Otherwise, the active power output adjustment value and the reactive power output adjustment value are set to zero.

[0009] The active power setpoint and reactive power setpoint of the energy storage converter are updated based on the calculated active power output adjustment value and reactive power output adjustment value.

[0010] Furthermore, the voltage reference value is adjusted based on the real-time collected voltage at the energy storage grid connection point, including:

[0011] When the voltage at the energy storage grid connection point is greater than the first voltage setting value, the set voltage reference value is the first voltage setting value;

[0012] When the voltage at the energy storage grid connection point is less than the second voltage setting value, the setting voltage reference value is the second voltage setting value;

[0013] When the voltage at the energy storage grid connection point is within the first set range, the set voltage reference value is the current energy storage grid connection point voltage.

[0014] Further, determining whether there is excessive voltage regulation includes:

[0015] If the voltage at the energy storage grid connection point is in the second set range and the absolute value of the given value of the current voltage regulation active power is greater than the second power setting value, it is determined that there is excessive voltage regulation. The second set range is a subset of the first set range, and the absolute value of the difference between the upper boundary of the first set range and the upper boundary of the second set range, as well as the absolute value of the difference between the lower boundary of the first set range and the lower boundary of the second set range, are all the third voltage setting value.

[0016] If the voltage at the grid connection point of the energy storage is within the second set range and the absolute value of the given value of the current active power of the energy storage converter is not greater than the second power set value, then it is determined that there is no overvoltage control.

[0017] Furthermore, the second power setting value and the active power reference adjustment value are set based on the third voltage setting value so that when the energy storage converter executes the updated set value of the active power and the set value of the reactive power of the energy storage converter, the resulting voltage deviation is not greater than the third voltage setting value.

[0018] Furthermore, the ratio between the active power output adjustment value and the reactive power output adjustment value is consistent with the line impedance ratio.

[0019] Furthermore, the setpoints for the active power and reactive power of the energy storage converter are updated based on the calculated active and reactive power output adjustment values, including:

[0020] Based on the calculated active power output adjustment value and reactive power output adjustment value, update the given value of voltage regulation active power and the given value of voltage regulation reactive power respectively.

[0021] The given values ​​for the active power and reactive power of the energy storage converter are generated based on the updated given values ​​for the active power and reactive power of the voltage regulation.

[0022] Furthermore, the active power output adjustment value and reactive power output adjustment value calculated based on the reactive power difference and line impedance ratio are expressed as follows:

[0023]

[0024] in, , These represent the active power output adjustment value and the reactive power output adjustment value, respectively. This represents the reactive power difference, where X represents the line reactance per unit length and R represents the line resistance per unit length. Indicates the line impedance ratio. .

[0025] Furthermore, the active power base adjustment value and reactive power output adjustment value calculated based on the active power reference adjustment value and the line impedance ratio are expressed as follows:

[0026]

[0027]

[0028] in, , These represent the active power output adjustment value and the reactive power output adjustment value, respectively. This indicates the set active power baseline adjustment value, and , This represents the given value of the active power for voltage regulation. This indicates the second power setting value.

[0029] Furthermore, the line impedance ratio is calculated after obtaining the impedance parameters per unit length of the line based on the line type.

[0030] Furthermore, if the line type is unknown or there are mixed line sections, the line impedance ratio of the corresponding line is calculated based on the active and reactive excitations under unit power and the voltage change amplitude obtained from the test.

[0031] Beneficial effects

[0032] By adopting the above-mentioned technical solution, the present invention has the following advantages and positive effects compared with the prior art:

[0033] This invention fully utilizes the inherent function of the reactive power voltage loop of the grid-type energy storage converter to autonomously adjust reactive power to support voltage. It directly calculates and generates active and reactive power adjustment command increments for voltage over-limit control based on the reactive power feedback value generated by its primary voltage regulation link. There is no need to calculate the specific voltage over-limit amplitude, and the voltage control speed is more efficient. Compared with traditional grid-type control, it can achieve better voltage support effect under the same energy storage capacity conditions.

[0034] This invention only requires obtaining the line model, without measuring the actual length of the line, which facilitates its promotion and application. In addition, if the line model is unknown or there are mixed line sections, the line impedance ratio of the corresponding line can be calculated based on the active and reactive excitations under unit power and the voltage change amplitude obtained by testing, without needing to know the actual impedance parameters of the line in advance.

[0035] This invention dynamically adjusts the voltage reference value of the reactive-voltage loop, so that no additional reactive power output is generated when the voltage does not exceed the limit, thereby reducing the power and capacity occupancy of the energy storage device and supporting other services such as three-phase imbalance management and heavy overload management in the transformer area.

[0036] This invention adaptively allocates the ratio of active and reactive power output based on line impedance characteristics. Under the same voltage control effect, it reduces the energy storage power and capacity configuration, while avoiding over-control. It precisely controls the line voltage near the upper and lower limits, minimizes the power consumption of the energy storage device, and significantly extends the effective working time of the energy storage device.

[0037] This invention uses the deviation between the actual value and the given value of reactive power as a feedback signal, which enables fast power regulation, shortens the duration of voltage over-limit, and effectively improves the power quality of the distribution area. Attached Figure Description

[0038] Figure 1 This is a flowchart illustrating an embodiment of the present invention;

[0039] Figure 2This is a control diagram illustrating an embodiment of the present invention;

[0040] Figure 3 This is a schematic diagram comparing the given and actual values ​​of active and reactive power for voltage management in traditional grid-type energy storage systems.

[0041] Figure 4 This is a schematic diagram of the voltage at the grid connection point for voltage management in traditional grid-type energy storage systems.

[0042] Figure 5 This is a schematic diagram comparing the given and actual values ​​of active and reactive power for voltage management in grid-type energy storage according to an embodiment of the present invention.

[0043] Figure 6 This is a schematic diagram of the grid connection point voltage for grid-connected energy storage voltage management according to an embodiment of the present invention. Detailed Implementation

[0044] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0045] The embodiments of the present invention relate to a voltage management method for grid-type energy storage distribution substations based on reactive power negative feedback adaptive adjustment of active and reactive power output. The aim is to solve the problem that traditional grid-type energy storage control usually only considers the characteristic that the line inductive reactance in a large power grid is much greater than the resistance, and relies on the voltage deviation signal of the reactive power loop to adjust the reactive power output, thus resulting in limited power quality improvement effect.

[0046] The main parameters involved in this implementation method include:

[0047] U pcc : Grid connection point voltage;

[0048] U ref Voltage reference value;

[0049] U max Line voltage upper limit (i.e., the first voltage setting value);

[0050] U min Line voltage lower limit (i.e., the second voltage setting value);

[0051] U dead Third voltage setting value;

[0052] The difference between the reactive power output value and the reactive power setpoint of the energy storage converter (i.e., reactive power difference).

[0053] : The threshold value for reactive power difference (i.e., the first power setting value).

[0054] : Active power output adjustment value for voltage management of energy storage converter;

[0055] : Voltage management reactive power output adjustment value of energy storage converter;

[0056] The baseline adjustment value for active power;

[0057] P vol : The setpoint value for the active power of the voltage regulation of the energy storage converter;

[0058] Q vol : The given value for reactive power management by the voltage of the energy storage converter;

[0059] P vol_lim : The set threshold for active power (i.e., the second power set value).

[0060] P ref : The setpoint value of the active power of the energy storage converter;

[0061] Q ref : The given value of reactive power of the energy storage converter.

[0062] This implementation method includes the following steps:

[0063] Step 1: Collect the grid connection point voltage U pcc Adjust the voltage reference value of the reactive power-voltage loop in real time.

[0064] If U pcc >U max Set U ref =U max ;

[0065] If U pcc min Set U ref =U min ;

[0066] If U min ≤U pcc ≤U max Set U ref =U pcc ;

[0067] Among them, U max U is the upper limit of the line voltage (i.e., the first voltage setting value). min U is the lower limit of the line voltage (i.e., the second voltage setting value). min ≤U pcc ≤U​max The first defined interval.

[0068] Step 2: Obtain the model of the power distribution line and determine the impedance parameters R and X per unit length of the line.

[0069] If the line type is unknown or there are mixed line sections in the actual project, the corresponding line voltage change can be tested by outputting active and reactive power excitations at unit power respectively. , Estimate the line impedance ratio in this area. .

[0070] in, The voltage variation of the line under unit active power output by the energy storage converter; This refers to the voltage variation of the line under a unit reactive power output by the energy storage converter.

[0071] Step 3: Based on the set voltage reference value of the reactive power-voltage loop, utilizing the inherent function of the grid-type energy storage converter's reactive power-voltage loop in autonomously regulating reactive power to support the voltage, the reactive power difference between the reactive power feedback value generated by its primary voltage regulation stage (i.e., the actual reactive power output value fed back to the reactive power-voltage loop) and the reactive power setpoint is directly calculated. The system calculates and generates given values ​​for active and reactive power used for voltage over-limit mitigation.

[0072] like Figure 1 As shown, the specific steps include:

[0073] Step 301: Collect the actual output value of reactive power and the given value of reactive power of the grid-type energy storage converter, and calculate the difference between the two. .

[0074] Step 302, determine the voltage range of the grid connection point:

[0075] If U pcc >U max Set Sec_Vol=1;

[0076] If U pcc min Set Sec_Vol=-1;

[0077] If U min ≤U pcc ≤U max Set Sec_Vol=0;

[0078] Step 303: Determine the reactive power difference. Does it exceed the set value? (i.e., the first power setting value);​

[0079] The threshold value for reactive power difference comparison is too small, which may lead to frequent adjustments in energy storage power output; too large a value will result in poor voltage management. When setting the reactive power difference setting value, the difference between the set voltage limit and the actual grid voltage limit must be considered. For example, if the lower limit for low voltage is set to 200V, and the actual grid voltage limit is 198V, a 2V margin should be reserved. That is, if the reactive power difference does not cause a voltage deviation greater than 2V, power adjustment may not be required.

[0080] like Proceed to step 3031; if Proceed to step 3032.

[0081] Step 3031: Determine whether Sec_Vol≠0 or Sec_Vol=0 and the Flag_Wait flag is set to 0.

[0082] If the above conditions are met, and combining the active and reactive power distribution ratio with the active and reactive power output adjustment formula derived from the voltage drop formula, the required increase in active and reactive power output adjustment value P for regulating the voltage storage converter can be calculated. adj Q adj .

[0083] If the above conditions are not met, the active and reactive power output adjustment values ​​P will not be adjusted. adj Q adj That is, P adj =0、Q adj =0.

[0084] The derivation process of the formulas for calculating the active and reactive power output adjustment values ​​is as follows:

[0085] The formula for line voltage drop is:

[0086]

[0087] In the formula, The line voltage variation is represented by l, the line length is represented by U, the line voltage is represented by P, the active power transmitted by the line is represented by U, and the reactive power transmitted by the line is represented by R and X, respectively, which represent the resistance and reactance parameters per unit length of the line.

[0088] When using active and reactive power superposition control output to control line voltage:

[0089]

[0090] Right now

[0091]

[0092] Combining active and reactive power allocation ratios We can obtain:

[0093]

[0094] Step 3032, determine whether the energy storage converter has been over-regulated:

[0095] If U min +U dead ≤U pcc ≤U max -U dead If the conditions are not met, it is believed that the energy storage converter does not suffer from over-regulation.

[0096] If U min +U dead ≤U pcc ≤U max -U dead The conditions are met, and it is suspected that there may be excessive regulation of low voltage; further assessment is needed.

[0097] If P vol >P vol_lim It is believed that the energy storage converter excessively manages low voltage, and therefore, the setpoints for the active and reactive power regulation of the energy storage converter (i.e., active power adjustment value and reactive power adjustment value) are set. , ( >0), and set the Flag_Wait flag to 1.

[0098] If P vol <-P vol_lim It is believed that energy storage converters excessively regulate high voltage, and therefore, active and reactive power adjustment values ​​for energy storage converters are set as follows: , ( >0), and set the Flag_Wait flag to 1.

[0099] If P vol ≤|P vol_lim | It is believed that the energy storage converter has not excessively regulated the voltage, and the active and reactive power output adjustment values ​​of the energy storage converter are set as follows: , At the same time, set the Flag_Wait flag to 0.

[0100] In the formula: P vol_lim The determination value indicating whether energy storage should perform voltage regulation (i.e., the second power setting value) must satisfy P. vol_lim The condition is >0. P vol_lim The value is mainly related to U dead The magnitude of (i.e., the third voltage setting value) is correlated and needs to satisfy P. vol_lim and The voltage drop across the line caused by the power output at this value is no greater than U. dead That's all.

[0101] To determine the baseline adjustment value for the active power output of energy storage after over-regulation, the following must be met: >0 condition. The value is also mainly related to U. dead The magnitude is correlated and needs to meet the adjustment requirements of the energy storage converter. and The voltage drop across the line caused by the power output is no greater than U. dead That's all.

[0102] The Flag_Wait flag can be set with a delay time, such as N times the control cycle. For example, when the control cycle is 10k, the delay time for waiting for the flag can be set to 100 times, i.e., 10ms, half of the fundamental cycle (the specific delay time depends on the system's active and reactive power response speed and adjustment speed).

[0103] Step 304: The adjusted active and reactive power values ​​calculated by the optimization algorithm are superimposed with the original voltage regulation active power setpoint and reactive power setpoint to obtain a new voltage regulation active and reactive power setpoint P. vol / Q vol That is, P vol =P vol +P adj Q vol =Q vol +Q adj .

[0104] Step 305: Calculate the active and reactive power setpoint P used for voltage regulation. vol / Q vol The new active and reactive power setpoints P of the energy storage converter are obtained by superimposing them with the original active and reactive power setpoints of the grid-type energy storage converter. ref and Q ref .

[0105] It is worth noting that the above active and reactive power parameters are subject to limitations, and the total system output power... If both active and reactive power support the voltage, ,but .

[0106] To prevent overcharging and over-discharging of energy storage, the state of charge (SBC) of the energy storage should not exceed the upper and lower limits. The SBC constraints are shown in the following formula:

[0107]

[0108] The energy storage charging and discharging power constraint is shown in the following formula:

[0109]

[0110] in, Let t be the state of charge of the stored energy. This is the limit of the state of charge. This represents the upper limit of the state of charge. This refers to the rated capacity of the energy storage. Let be the energy storage output power at time t. During energy storage operation, verification is performed. Whether the above constraints are met: if the State of Charge (SOC) exceeds the upper limit, the energy storage system is only allowed to discharge, not charge; if the SOC exceeds the lower limit, the energy storage system is only allowed to charge, not discharge. Once the SOC exceeds the limit, the system actively adjusts the active and reactive power setpoints P. ref / Q ref Prioritize ensuring the safety of the energy storage system itself.

[0111] The control block diagram of the grid-type distributed energy storage is as follows: Figure 2 As shown. Its input signals include the active and reactive power distribution ratio and the grid connection point voltage U. pcc Grid voltage upper and lower limits U min and U max Energy storage original active power given reactive power given Actual active power output of energy storage Actual reactive power output angular velocity Electromotive force .

[0112] Set the reactive power-voltage loop voltage reference value constraint:

[0113] U pcc min At that time, the voltage reference value of the reactive power-voltage loop is set to U. min ;

[0114] U pcc >U max At that time, the voltage reference value of the reactive power-voltage loop is set to U. max ;

[0115] U min ≤U pcc ≤U max At that time, the voltage reference value of the reactive power-voltage loop is set to U. pcc .

[0116] Reactive power-voltage loop voltage reference value and grid connection point voltage Feedback via reactive power-voltage droop circuit ​After processing, it serves as the voltage deviation adjustment signal for the reactive power-voltage loop.

[0117] Original energy storage converter active power setpoint With voltage regulation active power setpoint By superimposing these values, a new active power setpoint for the energy storage converter is obtained. ; With actual active power output The deviation enters the active-frequency loop (moment of inertia) of the synchronous machine type. Damping element Output angular velocity increment Superimposed rated angular velocity The angular velocity is obtained by subsequent integration. Integrate again to obtain the work angle. Ultimately, this controls the active power output of the energy storage.

[0118] Original energy storage converter reactive power setpoint With voltage control reactive power setpoint By superimposing these values, a new reactive power setpoint for the energy storage converter is obtained. ; With actual reactive power output The deviation, combined with the voltage loop and Deviation via drooping link (D) q The output of ) is processed through a reactive-voltage loop (gain) Generate electromotive force It controls the reactive power output of energy storage to achieve rapid voltage support.

[0119] The following example, using a simulated operating condition of a certain distribution radio area, will further illustrate this implementation method.

[0120] The low-voltage output phase voltage of the transformer in this distribution area is 220V, the line impedance ratio is 0.349 / 0.322, the load is 20kW from 0 to 2s, 50kW from 2 to 3s, 80kW from 3 to 4s, 50kW from 4 to 5s, 20kW from 5 to 6s, and 0kW from 6 to 8s.

[0121] Figure 3 and Figure 4 The figures show the active and reactive power setpoints P of the energy storage device under traditional grid-connected energy storage control when the line load fluctuates in real time. ref / Q ref And the actual values ​​of P / Q and the voltage at the end of the line. It can be seen that under the traditional grid-connected energy storage control, after the load increases to 80kW, the grid-connected energy storage converter actively increases the reactive power to 71kVA, while the active power remains basically unchanged, maintaining the minimum line voltage at 205V.

[0122] Figure 5 and Figure 6 The figures respectively demonstrate the active and reactive power setpoint P of the energy storage device under the grid-connected energy storage control proposed in this invention when the line load fluctuates in real time. ref / Q ref And the actual values ​​of P / Q and line end voltage. It can be seen that under the grid-connected energy storage control proposed in this invention, when the load fluctuates in real time, the steady-state line voltage never exceeds the limit (remaining above 200V), and the highest active and reactive power outputs of the grid-connected energy storage converter are 22kW and 21kVA respectively, with the energy storage output capacity being only... It is far smaller than the output capacity of traditional grid-type energy storage.

[0123] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for voltage management in grid-type energy storage distribution substations based on reactive power negative feedback adaptive adjustment of active and reactive power output, characterized in that, include: The voltage reference value is dynamically adjusted based on the voltage at the energy storage grid connection point. The reactive power difference is obtained by calculating the difference between the actual output value of the reactive power of the grid-type energy storage converter and the given value under the current voltage reference value. When the absolute value of the reactive power difference is less than or equal to the first power setting value, it is determined whether there is excessive voltage regulation. If there is excessive voltage regulation, the waiting flag is set to valid, and the active power output adjustment value and reactive power output adjustment value are calculated based on the set active power benchmark adjustment value and line impedance ratio. Otherwise, the waiting flag is set to invalid, and the active power output adjustment value and reactive power output adjustment value are set to zero. The waiting flag is used to indicate whether there is excessive voltage regulation. When the absolute value of the reactive power difference is greater than the first power setting value, if the voltage at the energy storage grid connection point is greater than the first voltage setting value or less than the second voltage setting value, or if the voltage at the energy storage grid connection point is in the first setting range and the waiting flag is invalid, then the active power output adjustment value and the reactive power output adjustment value are calculated based on the reactive power difference and the line impedance ratio. The first setting range is the range with the first voltage setting value as the upper boundary, the second voltage setting value as the lower boundary, and includes both the first voltage setting value and the second voltage setting value. Otherwise, the active power output adjustment value and the reactive power output adjustment value are set to zero. The active power setpoint and reactive power setpoint of the energy storage converter are updated based on the calculated active power output adjustment value and reactive power output adjustment value. in, Adjust the voltage reference value based on the real-time collected voltage at the energy storage grid connection point, including: When the voltage at the energy storage grid connection point is greater than the first voltage setting value, the set voltage reference value is the first voltage setting value; When the voltage at the energy storage grid connection point is less than the second voltage setting value, the setting voltage reference value is the second voltage setting value; When the voltage at the energy storage grid connection point is within the first set range, the set voltage reference value is the current voltage at the energy storage grid connection point. The active power output adjustment value and reactive power output adjustment value calculated based on the reactive power difference and line impedance ratio are expressed as follows: in, , These represent the active power output adjustment value and the reactive power output adjustment value, respectively. This represents the reactive power difference, where X represents the line reactance per unit length and R represents the line resistance per unit length. Indicates the line impedance ratio. ; The active power base adjustment value and reactive power output adjustment value, calculated based on the active power base adjustment value and the line impedance ratio, are expressed as follows: in, This indicates the set active power reference adjustment value, and , This represents the given value of the active power for voltage regulation. This indicates the second power setting value.

2. The voltage control method according to claim 1, characterized in that, Determining whether there is excessive voltage control includes: If the voltage at the energy storage grid connection point is in the second set range and the absolute value of the given value of the current voltage regulation active power is greater than the second power setting value, it is determined that there is excessive voltage regulation. The second set range is a subset of the first set range, and the absolute value of the difference between the upper boundary of the first set range and the upper boundary of the second set range, as well as the absolute value of the difference between the lower boundary of the first set range and the lower boundary of the second set range, are all the third voltage setting value. If the voltage at the grid connection point of the energy storage is within the second set range and the absolute value of the given value of the current active power of the energy storage converter is not greater than the second power set value, then it is determined that there is no overvoltage control.

3. The voltage control method according to claim 2, characterized in that, The second power setting value and the active power reference adjustment value are set based on the third voltage setting value so that when the energy storage converter executes the updated active power setting value and reactive power setting value of the energy storage converter, the resulting voltage deviation is not greater than the third voltage setting value.

4. The voltage control method according to claim 1, characterized in that, The ratio between the active power output adjustment value and the reactive power output adjustment value is consistent with the line impedance ratio.

5. The voltage control method according to claim 1, characterized in that, The setpoints for the active power and reactive power of the energy storage converter are updated based on the calculated active and reactive power output adjustment values, including: Based on the calculated active power output adjustment value and reactive power output adjustment value, update the given value of voltage regulation active power and the given value of voltage regulation reactive power respectively. The given values ​​for the active power and reactive power of the energy storage converter are generated based on the updated given values ​​for the active power and reactive power of the voltage regulation.

6. The voltage control method according to claim 1, characterized in that, The line impedance ratio is calculated based on the impedance parameters per unit length of the line according to the line type.

7. The voltage control method according to claim 6, characterized in that, If the line type is unknown or there are mixed line sections, the line impedance ratio of the corresponding line is calculated based on the active and reactive excitations under unit power and the voltage change amplitude obtained from the test.

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