Autonomous integrated control method, system, device and medium for distributed energy storage in medium and low voltage distribution networks

Abstract

The present invention discloses a method, system, device and medium for autonomous comprehensive control of distributed energy storage in medium and low voltage distribution networks. The method includes S1 acquiring local data of photovoltaic grid-connected points in a distributed photovoltaic distribution network; S2 using the distributed photovoltaic output power as the photovoltaic storage converged power and judging whether it meets the grid connection requirements. If it does, the photovoltaic grid is connected; otherwise, the distributed photovoltaic output power is smoothed based on the fluctuation smoothing method to obtain the photovoltaic storage converged power until the grid connection requirements are met and the energy storage smoothing power is calculated; S3 analyzing various working conditions based on system frequency and local power fluctuations; S4 calculating the energy storage frequency modulation power according to different working conditions; S5 calculating the energy storage reactive voltage regulation power; S6 using the energy storage smoothing power and the energy storage frequency modulation power to determine the energy storage autonomous comprehensive charging and discharging active power as the energy storage active power charging and discharging instruction. S7 using the energy storage reactive voltage regulation power to determine the energy storage autonomous comprehensive charging and discharging reactive power as the energy storage reactive power charging and discharging instruction. The present invention realizes the smoothing of power fluctuations and frequency and voltage regulation.

Description

Technical Field

[0001] The present invention relates to the field of distributed energy storage control, and in particular to a method, system, device and medium for autonomous comprehensive control of distributed energy storage in medium and low voltage distribution networks. Background Art

[0002] With the rapid development and penetration of new energy, large-scale grid connection cannot meet the requirements of stable operation of distribution network, which will cause problems such as node voltage deviation, frequency deviation and large power fluctuation rate. In order to cope with the impact of distributed photovoltaic access, at present, the distributed photovoltaic participation in distribution network interactive photovoltaic group adjustment and group control technology is mainly achieved by controlling the output of photovoltaic inverters. However, controlling photovoltaic inverters can only reduce photovoltaic power when the photovoltaic output is too large, which cannot meet the flexibility of the power grid in a short time scale.

[0003] Distributed energy storage, with its fast power regulation and charging and discharging power characteristics, discharges during peak loads and charges during valley loads, effectively achieving load peak shaving and valley filling and active support. It has played a major role in smoothing intermittent energy power fluctuations, peak shaving and valley filling, and improving voltage quality. Under the current background of photovoltaic group control groups, how to use the local data information of photovoltaic grid-connected points to accurately control energy storage while saving costs, so as to form a system that can respond to grid control targets in combination with photovoltaic group control and group dispatching systems and achieve precise local control in conjunction with photovoltaics is a problem currently faced. Therefore, real-time local control of distributed energy storage in medium and low voltage distribution networks can take into account frequency and voltage regulation and smooth local power fluctuations in the distribution network to prevent fluctuations from being transmitted to the main grid and affecting the flexibility of the grid in short time scales, and can also respond to grid control targets in combination with photovoltaic group control and group dispatching systems.

[0004] The autonomous comprehensive control strategy of distributed energy storage in medium and low voltage distribution networks will involve smoothing power fluctuations, primary frequency regulation and voltage regulation. At present, the control strategy of energy storage systems is basically based on the premise of smoothing photovoltaic power fluctuations to the grid-connected allowable range. On this basis, primary frequency regulation and optimization of energy storage SOC are added, and the effectiveness of the control method is verified by indicators such as power fluctuation rate and energy storage life. Energy storage autonomous comprehensive control needs to smooth photovoltaic power fluctuations when only local data information is available, and when photovoltaic power helps to restore system frequency, photovoltaic power is released to restore frequency by reducing energy storage charging and discharging power. At the same time, local voltage deviations must be considered, and the reactive power of energy storage is used to adjust the voltage while improving the utilization rate of energy storage. Therefore, the current energy storage control strategy is not suitable for autonomous comprehensive control of energy storage. Summary of the invention

[0005] The present invention aims at the problems of absorbing photovoltaic power fluctuations and frequency and voltage regulation faced by distributed energy storage in medium and low voltage distribution networks in the prior art, and provides a method, system, device and medium for autonomous comprehensive control of distributed energy storage in medium and low voltage distribution networks. By comprehensively considering the energy storage coordination control strategy of smoothing power fluctuations, frequency regulation and voltage regulation, the energy storage system can effectively deal with the impact of distributed photovoltaic access on medium and low voltage distribution networks locally, and can also respond to grid control targets in combination with group control and group regulation systems.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A method for autonomous integrated control of distributed energy storage in medium and low voltage distribution networks, comprising the following steps:

[0008] S1. Acquire local data of a photovoltaic grid-connected point including a distributed photovoltaic distribution network; the local data includes: distributed photovoltaic output power, system frequency, local power fluctuation and local voltage;

[0009] S2. Use the distributed photovoltaic output power as the photovoltaic energy storage combined power and determine whether it meets the grid connection requirements. If it meets the requirements, the photovoltaic energy is directly connected to the grid. If it does not meet the requirements, the distributed photovoltaic output power is smoothed based on the fluctuation smoothing method to obtain the photovoltaic energy storage combined power until the photovoltaic energy storage combined power meets the grid connection requirements, and then calculate the energy storage smoothing power; the energy storage smoothing power is used to smooth the fluctuation of the distributed photovoltaic output power;

[0010] S3, based on system frequency and local power fluctuations, the current system is divided into multiple working conditions for analysis;

[0011] S4. Calculate the energy storage frequency modulation power according to different working conditions at each moment to adjust the frequency deviation;

[0012] S5. Calculate the energy storage reactive voltage regulation power according to the local voltage at each moment, and use it to adjust the voltage deviation;

[0013] S6. Determine the energy storage active autonomous comprehensive charging and discharging power by using the energy storage smoothing power and the energy storage frequency modulation power, and use the energy storage active autonomous comprehensive charging and discharging power as the energy storage final active power charging and discharging instruction.

[0014] S7. Determine the energy storage reactive autonomous comprehensive charging and discharging power by using the energy storage reactive voltage regulation power, and use the energy storage reactive autonomous comprehensive charging and discharging power as the energy storage final reactive power charging and discharging instruction.

[0015] To optimize the above technical solutions, the specific measures taken also include:

[0016] Furthermore, in S1, the local data of the photovoltaic grid-connected point obtained is data on a time section.

[0017] Furthermore, in S2, the distributed photovoltaic output power is smoothed based on the fluctuation smoothing method to obtain the photovoltaic energy storage combined power until the photovoltaic energy storage combined power meets the grid connection requirements, and then the specific method for calculating the energy storage smoothing power is as follows:

[0018] Perform N-layer wavelet packet decomposition on the distributed photovoltaic output power, set the initial value of the wavelet packet decomposition layer N to 1, and perform the following calculations:

[0019]

[0020] Where P pv (t) is the distributed photovoltaic output power at time t, y a,t (t) is the wavelet basis function, where a is the scale factor, t is the shift factor, WT a,t (t) is the energy decomposed from the distributed photovoltaic output power to the base coordinate axis;

[0021] Reconstruction of N layer 2 N The power component P of the frequency band s (t), the power reconstruction process is as follows:

[0022]

[0023] Select the power component P s The low-frequency component P in (t) s，1 (t) as the combined power of solar energy storage;

[0024] If the combined power of the photovoltaic and energy storage still does not meet the grid connection requirements, the wavelet packet decomposition layer number N is increased by one, and the wavelet packet decomposition and power reconstruction steps are repeated until the combined power of the photovoltaic and energy storage meets the grid connection requirements. At this time, the power component P s The sum of the remaining high-frequency components in (t) is P W (t) acts as energy storage to smooth power.

[0025] Furthermore, in S2, the distributed photovoltaic output power is smoothed based on the fluctuation smoothing method to obtain the photovoltaic energy storage combined power until the photovoltaic energy storage combined power meets the grid connection requirements, and then the specific method for calculating the energy storage smoothing power is as follows:

[0026] The distributed photovoltaic output power is decomposed by the adaptive sliding average method with a smoothing window of M. The initial value of the smoothing window M is set to 1, and the following calculations are performed:

[0027] P s，1 (t) = [P pv (t-M+1)+P pv (t-M+2)+…+P pv (t)] / M

[0028] Where Ps，1 (t) is the combined power of light and energy storage, P pv (t) is the distributed photovoltaic output power at time t, M is the suppression window;

[0029] If the combined power of photovoltaic and energy storage still does not meet the grid connection requirements, the adaptive sliding average method will increase the smoothing window M by one, and the steps of the adaptive sliding average method will be repeated until the combined power of photovoltaic and energy storage meets the grid connection requirements. At this time, the difference P between the distributed photovoltaic output power and the combined power of photovoltaic and energy storage is calculated. W (t) is used as the energy storage smoothing power, and the formula is as follows:

[0030] P W (t) = P pv (t)-P s，1 (t)

[0031] Where P W (t) is the energy storage smoothing power.

[0032] Furthermore, S3 specifically includes:

[0033] Based on system frequency and local power fluctuations, the analysis is divided into multiple operating conditions:

[0034] DP pv =P pv (t-1)-P pv (t)

[0035] In the formula, DP pv is the power change, P pv (t) is the distributed photovoltaic output power at time t;

[0036] When the system frequency f(t) is at the upper limit of the system frequency regulation dead zone f H To the lower limit of the system frequency adjustment dead zone f L In the frequency regulation dead zone, the energy storage system does not need to undertake the system frequency regulation task, but only needs to smooth the distributed photovoltaic output power based on the wavelet packet decomposition method;

[0037] When the system frequency f(t) is at the lower limit f of the system frequency regulation dead zone at time t L To the lower limit of the normal deviation value of the system frequency f min During this period, the energy storage system needs to take on the task of regulating the system frequency while smoothing the local fluctuations. The power change DP at this time will be calculated based on the energy storage smoothing power. pv Determine whether it is necessary to superimpose an energy storage frequency modulation power;

[0038] When the system frequency f(t) is at the upper limit of the normal deviation value of the system frequency at time t max To the upper limit of the system frequency adjustment dead zone f HDuring this period, the energy storage system needs to take on the task of regulating the system frequency while smoothing the local fluctuations. The power change DP at this time will be calculated based on the energy storage smoothing power. pv Determine whether it is necessary to superimpose an energy storage frequency modulation power;

[0039] When the system frequency f(t) at time t is lower than the lower limit of the normal deviation of the system frequency f min If the energy storage smoothing power is used to control the energy storage charging, the energy storage smoothing power is directly set to 0; when the system frequency f(t) at time t is higher than the upper limit of the normal deviation value of the system frequency f max If the energy storage smoothing power is used to control the energy storage discharge, the energy storage smoothing power is directly set to 0.

[0040] Furthermore, in S4, the energy storage frequency regulation power is calculated according to different working conditions at each moment, and the method for adjusting the frequency deviation is as follows:

[0041] Energy storage frequency modulation power P f (t) is calculated as follows:

[0042]

[0043] Where P pv (t) is the distributed photovoltaic output power at time t, P s，1 (t) is the combined power of photovoltaic power and energy storage, f max and f min are the upper and lower limits of the normal deviation of the system frequency, f H and f L are the upper and lower limits of the system frequency adjustment dead zone, K is the local frequency modulation coefficient, and f(t) is the system frequency at time t.

[0044] Furthermore, in S4, the energy storage frequency regulation power is calculated according to different working conditions at each moment as follows:

[0045] Energy storage frequency modulation power P f (t) is calculated as follows:

[0046]

[0047] In the formula, k f is the active frequency modulation coefficient, P N is the energy storage rated power; f max and f min are the upper and lower limits of the normal deviation of the system frequency, f H and f L are the upper and lower limits of the dead zone range of the system frequency adjustment, f(t) is the system frequency at time t, and f N is the rated frequency of the system.

[0048] Furthermore, S5 is specifically:

[0049] The reactive voltage regulation power of energy storage is calculated as follows:

[0050]

[0051] In the formula, Q U (t) is the reactive voltage regulation power of energy storage at time t, K U is the reactive voltage regulation coefficient of energy storage, U max , U min are the upper and lower limits of the allowable voltage range respectively, and U(t) is the local voltage at time t.

[0052] Further, in S6, the calculation formula of the energy storage active autonomous comprehensive charging and discharging power is as follows:

[0053] P ESS (t) = P W (t)+P f (t)

[0054] Where P ESS (t) is the autonomous comprehensive charging and discharging power of energy storage active power P f (t) is the energy storage frequency modulation power, P W (t) is the energy storage smoothing power.

[0055] Further, in S7, the calculation formula of the energy storage reactive autonomous comprehensive charging and discharging power is as follows:

[0056] Q ESS (t) = Q U (t)

[0057] In the formula, Q ESS (t) is the autonomous comprehensive charging and discharging power of energy storage reactive power, Q U (t) is the reactive voltage regulation power of energy storage at time t.

[0058] Furthermore, the upper limit of the normal deviation value of the system frequency f max and the lower limit f min The values ​​of are 50.2Hz and 49.8Hz respectively, and the upper limit of the dead zone range of the system frequency adjustment is f H and the lower limit f L The values ​​are 50.03Hz and 49.97Hz respectively, and the local frequency modulation coefficient K ranges from 0.2 to 0.5.

[0059] Furthermore, the active frequency modulation coefficient k f The value range is 5-50.

[0060] Furthermore, the value of the energy storage reactive voltage regulation coefficient is specifically 21.

[0061] The present invention also proposes a distributed energy storage autonomous integrated control system for medium and low voltage distribution networks, comprising:

[0062] A data acquisition module is used to obtain local data of a photovoltaic grid-connected point including a distributed photovoltaic distribution network; the local data includes: distributed photovoltaic output power, system frequency, local power fluctuation and local voltage;

[0063] The power smoothing module is used to use the distributed photovoltaic output power as the photovoltaic energy storage combined power and determine whether it meets the grid connection requirements. If it meets the requirements, the photovoltaic energy is directly connected to the grid. If it does not meet the requirements, the distributed photovoltaic output power is smoothed based on the fluctuation smoothing method to obtain the photovoltaic energy storage combined power until the photovoltaic energy storage combined power meets the grid connection requirements, and then the energy storage smoothing power is calculated; the energy storage smoothing power is used to smooth the fluctuation of the distributed photovoltaic output power;

[0064] The frequency adjustment module is used to analyze the current system into multiple operating conditions based on system frequency and local power fluctuations, and calculate the energy storage frequency regulation power according to different operating conditions at each moment to adjust the frequency deviation;

[0065] The voltage adjustment module is used to calculate the energy storage reactive voltage regulation power according to the local voltage at each moment, and is used to adjust the voltage deviation;

[0066] The instruction calculation module determines the energy storage active autonomous comprehensive charging and discharging power by using the energy storage smoothing power and the energy storage frequency regulation power, and uses the energy storage active autonomous comprehensive charging and discharging power as the energy storage final active power charging and discharging instruction; determines the energy storage reactive autonomous comprehensive charging and discharging power by using the energy storage reactive voltage regulation power, and uses the energy storage reactive autonomous comprehensive charging and discharging power as the energy storage final reactive power charging and discharging instruction.

[0067] To optimize the above technical solutions, the specific measures taken also include:

[0068] Furthermore, the local data of the photovoltaic grid-connected point obtained is data on a time section.

[0069] Furthermore, the method for smoothing the output power of distributed photovoltaic power generation based on the fluctuation smoothing method to obtain the combined power of photovoltaic energy storage, until the combined power of photovoltaic energy storage meets the grid connection requirements, and then calculating the energy storage smoothing power is as follows:

[0070] Perform N-layer wavelet packet decomposition on the distributed photovoltaic output power, set the initial value of the wavelet packet decomposition layer N to 1, and perform the following calculations:

[0071]

[0072] Where P pv (t) is the distributed photovoltaic output power at time t; y a,t(t) is the wavelet basis function, where a is the scale factor, t is the shift factor, WT a,t (t) is the energy decomposed from the distributed photovoltaic output power to the base coordinate axis;

[0073] Reconstruction of N layer 2 N The power component P of the frequency band s (t), the power reconstruction process is as follows:

[0074]

[0075] Select the power component P s The low-frequency component P in (t) s，1 (t) as the combined power of light and energy storage;

[0076] If the combined power of the photovoltaic and energy storage still does not meet the grid connection requirements, the wavelet packet decomposition layer number N is increased by one, and the wavelet packet decomposition and power reconstruction steps are repeated until the combined power of the photovoltaic and energy storage meets the grid connection requirements. At this time, the power component P s The sum of the remaining high-frequency components in (t) is P W (t) acts as energy storage to smooth power.

[0077] Furthermore, the method for smoothing the output power of distributed photovoltaic power generation based on the fluctuation smoothing method to obtain the combined power of photovoltaic energy storage, until the combined power of photovoltaic energy storage meets the grid connection requirements, and then calculating the energy storage smoothing power is as follows:

[0078] The distributed photovoltaic output power is decomposed by the adaptive sliding average method with a smoothing window of M. The initial value of the smoothing window M is set to 1, and the following calculations are performed:

[0079] P s，1 (t) = [P pv (t-M+1)+P pv (t-M+2)+…+P pv (t)] / M

[0080] Where P s，1 (t) is the combined power of light and energy storage, P pv (t) is the distributed photovoltaic output power at time t, M is the suppression window;

[0081] If the combined power of photovoltaic and energy storage still does not meet the grid connection requirements, the adaptive sliding average method will increase the smoothing window M by one, and the steps of the adaptive sliding average method will be repeated until the combined power of photovoltaic and energy storage meets the grid connection requirements. At this time, the difference P between the distributed photovoltaic output power and the combined power of photovoltaic and energy storage is calculated. W (t) is used as the energy storage smoothing power, and the formula is as follows:

[0082] P W (t) = P pv (t)-Ps，1 (t)

[0083] Where P W (t) is the energy storage smoothing power.

[0084] Furthermore, based on the system frequency and local power fluctuation, the current system is divided into multiple working conditions for analysis, specifically:

[0085] Based on system frequency and local power fluctuations, the analysis is divided into multiple operating conditions:

[0086] DP pv =P pv (t-1)-P pv (t)

[0087] In the formula, DP pv is the power change, P pv (t) is the distributed photovoltaic output power at time t;

[0088] When the system frequency f(t) is at the upper limit of the system frequency regulation dead zone f H To the lower limit of the system frequency adjustment dead zone f L In the frequency regulation dead zone, the energy storage system does not need to undertake the system frequency regulation task, but only needs to smooth the distributed photovoltaic output power based on the wavelet packet decomposition method;

[0089] When the system frequency f(t) is at the lower limit f of the system frequency regulation dead zone at time t L To the lower limit of the normal deviation value of the system frequency f min During this period, the energy storage system needs to take on the task of regulating the system frequency while smoothing the local fluctuations. The power change DP at this time will be calculated based on the energy storage smoothing power. pv Determine whether it is necessary to superimpose an energy storage frequency modulation power;

[0090] When the system frequency f(t) is at the upper limit of the normal deviation value of the system frequency at time t max To the upper limit of the system frequency adjustment dead zone f H During this period, the energy storage system needs to take on the task of regulating the system frequency while smoothing the local fluctuations. The power change DP at this time will be calculated based on the energy storage smoothing power. pv Determine whether it is necessary to superimpose an energy storage frequency modulation power;

[0091] When the system frequency f(t) at time t is lower than the lower limit of the normal deviation of the system frequency f min If the energy storage smoothing power is used to control the energy storage charging, the energy storage smoothing power is directly set to 0; when the system frequency f(t) at time t is higher than the upper limit of the normal deviation value of the system frequency f maxIf the energy storage smoothing power is used to control the energy storage discharge, the energy storage smoothing power is directly set to 0.

[0092] Furthermore, the method for calculating the energy storage frequency modulation power according to different working conditions at each moment and adjusting the frequency deviation is as follows:

[0093] Energy storage frequency modulation power P f (t) is calculated as follows:

[0094]

[0095] Where P pv (t) is the distributed photovoltaic output power at time t, P s，1 (t) is the combined power of photovoltaic power and energy storage, f max and f min are the upper and lower limits of the normal deviation of the system frequency, f H and f L are the upper and lower limits of the system frequency adjustment dead zone, K is the local frequency modulation coefficient, and f(t) is the system frequency at time t.

[0096] Furthermore, the calculation of energy storage frequency modulation power according to different working conditions at each moment is specifically as follows:

[0097] Energy storage frequency modulation power P f (t) is calculated as follows:

[0098]

[0099] In the formula, k f is the active frequency modulation coefficient, P N is the energy storage rated power; f max and f min are the upper and lower limits of the normal deviation of the system frequency, f H and f L are the upper and lower limits of the dead zone range of the system frequency adjustment, f(t) is the system frequency at time t, and f N is the rated frequency of the system.

[0100] Furthermore, the calculation of the energy storage reactive voltage regulation power according to the local voltage at each moment is specifically as follows:

[0101] The reactive voltage regulation power of energy storage is calculated as follows:

[0102]

[0103] In the formula, Q U (t) is the reactive voltage regulation power of energy storage at time t, K U is the reactive voltage regulation coefficient of energy storage, U max , U minare the upper and lower limits of the allowable voltage range respectively, and U(t) is the local voltage at time t.

[0104] Furthermore, the calculation formula of the energy storage active autonomous comprehensive charging and discharging power is as follows:

[0105] P ESS (t) = P W (t)+P f (t)

[0106] Where P ESS (t) is the autonomous comprehensive charging and discharging power of energy storage active power, P f (t) is the energy storage frequency modulation power, P W (t) is the energy storage smoothing power.

[0107] Furthermore, the calculation formula of the energy storage reactive autonomous comprehensive charging and discharging power is as follows:

[0108] Q ESS (t) = Q U (t)

[0109] In the formula, Q ESS (t) is the autonomous comprehensive charging and discharging power of energy storage reactive power, Q U (t) is the reactive voltage regulation power of energy storage at time t.

[0110] Furthermore, the upper limit of the normal deviation value of the system frequency f max and the lower limit f min The values ​​are 50.2Hz and 49.8Hz respectively, and the local frequency modulation coefficient K ranges from 0.2 to 0.5.

[0111] Furthermore, the active frequency modulation coefficient k f The value range is 5-50.

[0112] Furthermore, the value of the energy storage reactive voltage regulation coefficient is specifically 21.

[0113] The present invention also proposes an electronic device, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the above-mentioned distributed energy storage autonomous integrated control method for medium and low voltage distribution networks is implemented.

[0114] The present invention also proposes a computer-readable storage medium storing a computer program, wherein the computer program enables a computer to execute the above-mentioned method for autonomous integrated control of distributed energy storage in medium and low voltage distribution networks.

[0115] The beneficial effects of the present invention are:

[0116] The present invention aims at the power fluctuation, frequency deviation and voltage deviation problems caused by distributed photovoltaic access in medium and low voltage distribution networks. In order to cope with the situation where the photovoltaic group control and group modulation system has communication delay or communication interruption, which leads to large deviations in the group control and group modulation effects, the distributed photovoltaic power is smoothed to obtain the grid-connected power based on the wavelet packet decomposition method by real-time acquisition of local information such as voltage, frequency, and power change rate of the photovoltaic grid-connected point of the distribution network, and then the energy storage adaptive frequency modulation power is calculated according to different working conditions at each moment. At the same time, the energy storage voltage regulation power is calculated considering the local voltage at each moment, and finally the energy storage charging and discharging power is determined. The present invention solves the practical problem that the local control of energy storage needs to smooth the photovoltaic power fluctuation under the condition of only local data information, and also needs to consider the adjustment of frequency, and also needs to consider the adjustment of local voltage deviation, and realizes the autonomous comprehensive control of distributed energy storage. The energy storage system can not only smooth power fluctuations and frequency and voltage modulation locally, but also can be combined with the group control and group modulation system to respond to the control target of the power grid for scientific control. BRIEF DESCRIPTION OF THE DRAWINGS

[0117] Figure 1 It is a flow chart of the autonomous comprehensive control method of distributed energy storage in low-voltage distribution network of the present invention;

[0118] Figure 2 It is a 33-node distribution line topology structure in an embodiment of the present invention;

[0119] Figure 3 is a 24-hour curve of the typical daily photovoltaic power generation at the node 31 in the embodiment of the present invention;

[0120] Figure 4 is the combined solar-energy-storage power calculated according to specific operating conditions in the embodiment of the present invention;

[0121] Figure 5 is the combined power of photovoltaic power and energy storage participating in the frequency modulation task calculated in the embodiment of the present invention;

[0122] Figure 6 It is the autonomous comprehensive charging and discharging power of the energy storage active power in the embodiment of the present invention.

[0123] Figure 7 It is the autonomous comprehensive charging and discharging power of the energy storage reactive power in the embodiment of the present invention. DETAILED DESCRIPTION

[0124] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0125] Embodiment 1

[0126] The present invention proposes a method for autonomous comprehensive control of distributed energy storage in medium and low voltage distribution networks. The flowchart of the method is as follows: Figure 1 As shown, the following steps are included:

[0127] S1. Acquire local data of a photovoltaic grid-connected point including a distributed photovoltaic distribution network; the local data includes: distributed photovoltaic output power, system frequency, local power fluctuation and local voltage. The local data of the photovoltaic grid-connected point acquired is data in a time section.

[0128] See also Figure 2 In the 33-node distribution line topology, the photovoltaic system is integrated into the three feeder nodes 9, 28, and 31 respectively. 24 hours are selected for analysis. The 24-hour photovoltaic power generation curve of the 31-node is shown in Figure 3 , with a maximum power of 960kW. Based on the publicly available 33-node distribution line topology data, power data and other information, in order to meet the real-time control accuracy and verify whether it meets the State Grid’s new energy grid connection requirements, the data time interval is at least 1 minute.

[0129] S2. Use the distributed photovoltaic output power as the photovoltaic energy storage combined power and determine whether it meets the grid connection requirements. If it meets the requirements, the photovoltaic energy is directly connected to the grid. If it does not meet the requirements, the distributed photovoltaic output power is smoothed based on the fluctuation smoothing method to obtain the photovoltaic energy storage combined power until the photovoltaic energy storage combined power meets the grid connection requirements, and then calculate the energy storage smoothing power; the energy storage smoothing power is used to smooth the fluctuation of the distributed photovoltaic output power;

[0130] The method for smoothing fluctuations can be wavelet packet decomposition or adaptive sliding average method decomposition, or other methods.

[0131] The wavelet packet decomposition method is as follows:

[0132] Perform N-layer wavelet packet decomposition on the distributed photovoltaic output power, set the initial value of the wavelet packet decomposition layer N to 1, and perform the following calculations:

[0133]

[0134] Where P pv (t) is the distributed photovoltaic output power at time t, y a,t (t) is the wavelet basis function, where a is the scale factor, t is the shift factor, WT a,t (t) is the energy decomposed from the distributed photovoltaic output power to the base coordinate axis;

[0135] Reconstruction of N layer 2 N The power component P of the frequency band s (t), the power reconstruction process is as follows:

[0136]

[0137] Select the power component P s The low-frequency component P in (t) s，1 (t) as the combined power of solar energy storage;

[0138] If the combined power of the photovoltaic and energy storage still does not meet the grid connection requirements, the wavelet packet decomposition layer number N is increased by one, and the wavelet packet decomposition and power reconstruction steps are repeated until the combined power of the photovoltaic and energy storage meets the grid connection requirements. At this time, the power component P s The sum of the remaining high-frequency components in (t) is P W (t) acts as energy storage to smooth power.

[0139] The adaptive sliding average method decomposition method is as follows:

[0140] The distributed photovoltaic output power is decomposed by the adaptive sliding average method with a smoothing window of M. The initial value of the smoothing window M is set to 1, and the following calculations are performed:

[0141] P s，1 (t) = [P pv (t-M+1)+P pv (t-M+2)+…+P pv (t)] / M

[0142] Where P s，1 (t) is the combined power of light and energy storage, P pv (t) is the distributed photovoltaic output power at time t, M is the suppression window;

[0143] If the combined power of photovoltaic and energy storage still does not meet the grid connection requirements, the adaptive sliding average method will increase the smoothing window M by one, and the steps of the adaptive sliding average method will be repeated until the combined power of photovoltaic and energy storage meets the grid connection requirements. At this time, the difference P between the distributed photovoltaic output power and the combined power of photovoltaic and energy storage is calculated. W (t) is used as the energy storage smoothing power, and the formula is as follows:

[0144] P W (t) = P pv (t)-P s，1 (t)

[0145] Where P W (t) is the energy storage smoothing power.

[0146] According to the grid connection requirements, the 1-minute allowable fluctuation value of 31-node photovoltaic is 96kW, and the 10-minute allowable fluctuation value is 320kW. Figure 4 The calculated 24h solar-storage combined power meets the grid-connected requirements.

[0147] S3. Based on the system frequency and local power fluctuations, the current system is divided into multiple working conditions for analysis; specifically including:

[0148] Based on system frequency and local power fluctuations, the analysis is divided into multiple operating conditions:

[0149] DP pv =P pv (t-1)-P pv (t)

[0150] In the formula, DP pv is the power change, P pv (t) is the distributed photovoltaic output power at time t;

[0151] When the system frequency f(t) is at the upper limit of the system frequency regulation dead zone f H To the lower limit of the system frequency adjustment dead zone f L In the frequency regulation dead zone, the energy storage system does not need to undertake the system frequency regulation task, but only needs to smooth the distributed photovoltaic output power based on the wavelet packet decomposition method;

[0152] When the system frequency f(t) is at the lower limit f of the system frequency regulation dead zone at time t L To the lower limit of the normal deviation value of the system frequency f min During this period, the energy storage system needs to take on the task of regulating the system frequency while smoothing the local fluctuations. The power change DP at this time will be calculated based on the energy storage smoothing power. pv Determine whether it is necessary to superimpose an energy storage frequency modulation power;

[0153] When the system frequency f(t) is at the upper limit of the normal deviation value of the system frequency at time t max To the upper limit of the system frequency adjustment dead zone f H During this period, the energy storage system needs to take on the task of regulating the system frequency while smoothing the local fluctuations. The power change DP at this time will be calculated based on the energy storage smoothing power. pv Determine whether it is necessary to superimpose an energy storage frequency modulation power;

[0154] When the system frequency f(t) at time t is lower than the lower limit of the normal deviation of the system frequency f min If the energy storage smoothing power is used to control the energy storage charging, the energy storage smoothing power is directly set to 0; when the system frequency f(t) at time t is higher than the upper limit of the normal deviation value of the system frequency f max If the energy storage smoothing power is used to control the energy storage discharge, the energy storage smoothing power is directly set to 0.

[0155] See also Figure 5, the energy storage frequency regulation power is calculated, and the photovoltaic storage combined power participating in the frequency regulation task is further calculated. It can be seen that at this time, the photovoltaic storage combined power will be adjusted according to the frequency of the current period. When the frequency deviation is large, the energy storage reduces the suppression of the photovoltaic power, and uses the photovoltaic power to actively support the frequency.

[0156] S4. Calculate the energy storage frequency modulation power according to different working conditions at each moment to adjust the frequency deviation; the method is as follows:

[0157] Energy storage frequency modulation power P f (t) is calculated as follows:

[0158]

[0159] Where P pv (t) is the distributed photovoltaic output power at time t, P s，1 (t) is the combined power of photovoltaic power and energy storage, f max and f min are the upper and lower limits of the normal deviation of the system frequency, f H and f L are the upper and lower limits of the dead zone range of the system frequency adjustment, K is the local frequency adjustment coefficient, and f(t) is the system frequency at time t. The upper limit of the normal deviation value of the system frequency is f max and the lower limit f min The values ​​of are 50.2Hz and 49.8Hz respectively, and the upper limit of the dead zone range of the system frequency adjustment is f H and the lower limit f L The values ​​are 50.03Hz and 49.97Hz respectively, and the local frequency modulation coefficient K ranges from 0.2 to 0.5.

[0160] The specific method of calculating the energy storage frequency modulation power according to different working conditions at different times can also be:

[0161] Energy storage frequency modulation power P f (t) is calculated as follows:

[0162]

[0163] In the formula, k f is the active frequency modulation coefficient, P N is the energy storage rated power; f max and f min are the upper and lower limits of the normal deviation of the system frequency, f H and f L are the upper and lower limits of the dead zone range of the system frequency adjustment, f(t) is the system frequency at time t, and f N is the rated frequency of the system. Active frequency modulation coefficient k f The value range is 5-50.

[0164] S5. To improve the utilization rate of energy storage, the energy storage reactive power is used for local voltage regulation. The energy storage reactive voltage regulation power is calculated according to the local voltage at each moment and used to adjust the voltage deviation. Specifically:

[0165] The reactive voltage regulation power of energy storage is calculated as follows:

[0166]

[0167] In the formula, Q U (t) is the reactive voltage regulation power of energy storage at time t, K U is the reactive voltage regulation coefficient of energy storage, ranging from 12.5 to 33.3, U max , U min They are the upper and lower limits of the voltage allowable range, generally 1.05-0.95pu. U(t) is the local voltage at time t.

[0168] S6. Determine the energy storage active autonomous comprehensive charge and discharge power by using the energy storage smoothing power and the energy storage frequency modulation power, and use the energy storage active autonomous comprehensive charge and discharge power as the energy storage final active power charge and discharge instruction;

[0169] S7. Determine the energy storage reactive autonomous comprehensive charging and discharging power by using the energy storage reactive voltage regulation power, and use the energy storage reactive autonomous comprehensive charging and discharging power as the energy storage final reactive power charging and discharging instruction.

[0170] The calculation formula of the autonomous comprehensive charging and discharging power of energy storage active power is as follows:

[0171] P ESS (t) = P W (t)+P f (t)

[0172] Where P ESS (t) is the autonomous comprehensive charging and discharging power of energy storage active power P f (t) is the energy storage frequency modulation power, P W (t) is the energy storage smoothing power.

[0173] The calculation formula of the energy storage reactive autonomous comprehensive charging and discharging power is as follows:

[0174] Q ESS (t) = Q U (t)

[0175] In the formula, Q ESS (t) is the autonomous comprehensive charging and discharging power of energy storage reactive power, Q U (t) is the reactive voltage regulation power of energy storage at time t.

[0176] See also Figure 6 , the autonomous comprehensive charging and discharging power of energy storage active power is calculated.

[0177] See also Figure 7 , the energy storage reactive autonomous comprehensive charging and discharging power is obtained by calculating the reactive voltage regulation coefficient.

[0178] Embodiment 2

[0179] The present invention proposes a medium and low voltage distribution network distributed energy storage autonomous integrated control system corresponding to the method of embodiment 1, comprising:

[0180] A data acquisition module is used to obtain local data of a photovoltaic grid-connected point including a distributed photovoltaic distribution network; the local data includes: distributed photovoltaic output power, system frequency, local power fluctuation and local voltage;

[0181] The power smoothing module is used to use the distributed photovoltaic output power as the photovoltaic energy storage combined power and determine whether it meets the grid connection requirements. If it meets the requirements, the photovoltaic energy is directly connected to the grid. If it does not meet the requirements, the distributed photovoltaic output power is smoothed based on the fluctuation smoothing method to obtain the photovoltaic energy storage combined power until the photovoltaic energy storage combined power meets the grid connection requirements, and then the energy storage smoothing power is calculated; the energy storage smoothing power is used to smooth the fluctuation of the distributed photovoltaic output power;

[0182] The frequency adjustment module is used to analyze the current system into multiple operating conditions based on system frequency and local power fluctuations, and calculate the energy storage frequency regulation power according to different operating conditions at each moment to adjust the frequency deviation;

[0183] The voltage adjustment module is used to calculate the energy storage reactive voltage regulation power according to the local voltage at each moment, and is used to adjust the voltage deviation;

[0184] The instruction calculation module determines the energy storage active autonomous comprehensive charging and discharging power by using the energy storage smoothing power and the energy storage frequency regulation power, and uses the energy storage active autonomous comprehensive charging and discharging power as the energy storage final active power charging and discharging instruction; determines the energy storage reactive autonomous comprehensive charging and discharging power by using the energy storage reactive voltage regulation power, and uses the energy storage reactive autonomous comprehensive charging and discharging power as the energy storage final reactive power charging and discharging instruction.

[0185] The implementation methods of each module and module function in the system are completely consistent with the steps of the method in Example 1, so they will not be repeated here.

[0186] Embodiment 3

[0187] The present invention proposes an electronic device, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the autonomous integrated control method for distributed energy storage in medium and low voltage distribution networks as described in Example 1 is implemented.

[0188] Embodiment 4

[0189] The present invention provides a computer-readable storage medium storing a computer program, wherein the computer program enables a computer to execute the autonomous integrated control method for distributed energy storage in a medium and low voltage distribution network as described in the first embodiment.

[0190] In the embodiments disclosed in the present application, the computer storage medium can be a tangible medium that can contain or store a program for use by or in conjunction with an instruction execution system, device or equipment. The computer storage medium can include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, devices or equipment, or any suitable combination of the above. More specific examples of computer storage media can include electrical connections based on one or more lines, portable computer disks, hard disks, random access memories (RAM), read-only memories (ROM), erasable programmable read-only memories (EPROM or flash memory), optical fibers, portable compact disk read-only memories (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the above.

[0191] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed in this application can be implemented in electronic hardware or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0192] The above are only preferred embodiments of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should be regarded as the protection scope of the present invention.

Claims

1. A method for autonomous comprehensive control of distributed energy storage in medium and low voltage distribution networks, characterized in that: The following steps are involved: S1. Acquire local data of a photovoltaic grid-connected point including a distributed photovoltaic distribution network; the local data includes: distributed photovoltaic output power, system frequency, local power fluctuation and local voltage; S2. Use the distributed photovoltaic output power as the photovoltaic energy storage combined power and determine whether it meets the grid connection requirements. If it meets the requirements, the photovoltaic energy is directly connected to the grid. If it does not meet the requirements, the distributed photovoltaic output power is smoothed based on the fluctuation smoothing method to obtain the photovoltaic energy storage combined power until the photovoltaic energy storage combined power meets the grid connection requirements, and then calculate the energy storage smoothing power; the energy storage smoothing power is used to smooth the fluctuation of the distributed photovoltaic output power; S3: Based on the system frequency and local power fluctuations, the current system is divided into multiple working conditions for analysis; S3 specifically includes: Based on system frequency and local power fluctuations, the analysis is divided into multiple operating conditions: ΔP pv =P pv (t-1)-P pv (t) Where ΔP pv is the power change, P pv (t) is the distributed photovoltaic output power at time t; When the system frequency f(t) is at the upper limit of the system frequency regulation dead zone f H To the lower limit of the system frequency adjustment dead zone f L In the frequency regulation dead zone, the energy storage system does not need to undertake the system frequency regulation task, but only needs to smooth the distributed photovoltaic output power based on the wavelet packet decomposition method; When the system frequency f(t) is at the lower limit f of the system frequency regulation dead zone at time t L To the lower limit of the normal deviation value of the system frequency f min When the energy storage system is between 200 and 250 km, it needs to take on the task of frequency regulation while smoothing the local fluctuations. The power change ΔP at this time will be calculated based on the energy storage smoothing power. pv Determine whether it is necessary to superimpose an energy storage frequency modulation power; When the system frequency f(t) is at the upper limit of the normal deviation value of the system frequency at time t max To the upper limit of the system frequency adjustment dead zone f H When the energy storage system is between 200 and 250 km, it needs to take on the task of frequency regulation while smoothing the local fluctuations. The power change ΔP at this time will be calculated based on the energy storage smoothing power. pv Determine whether it is necessary to superimpose an energy storage frequency modulation power; When the system frequency f(t) at time t is lower than the lower limit of the normal deviation of the system frequency f min If the energy storage smoothing power is used to control the energy storage charging, the energy storage smoothing power is directly set to 0; when the system frequency f(t) at time t is higher than the upper limit of the normal deviation value of the system frequency f max If the energy storage smoothing power is used to control the energy storage discharge, the energy storage smoothing power is directly set to 0; S4. Calculate the energy storage frequency modulation power according to different working conditions at each moment to adjust the frequency deviation; S5. Calculate the energy storage reactive voltage regulation power according to the local voltage at each moment, and use it to adjust the voltage deviation; S6. Determine the energy storage active autonomous comprehensive charge and discharge power by using the energy storage smoothing power and the energy storage frequency modulation power, and use the energy storage active autonomous comprehensive charge and discharge power as the energy storage final active power charge and discharge instruction; S7. Determine the energy storage reactive autonomous comprehensive charging and discharging power by using the energy storage reactive voltage regulation power, and use the energy storage reactive autonomous comprehensive charging and discharging power as the energy storage final reactive power charging and discharging instruction.

2. The autonomous comprehensive control method for distributed energy storage in medium and low voltage distribution networks according to claim 1, characterized in that: In S1, the local data of the photovoltaic grid-connected point obtained is data at a time section.

3. The autonomous comprehensive control method for distributed energy storage in medium and low voltage distribution networks according to claim 1, characterized in that: In S2, the distributed photovoltaic output power is smoothed based on the fluctuation smoothing method to obtain the photovoltaic energy storage combined power until the photovoltaic energy storage combined power meets the grid connection requirements, and then the specific method for calculating the energy storage smoothing power is as follows: Perform N-layer wavelet packet decomposition on the distributed photovoltaic output power, set the initial value of the wavelet packet decomposition layer N to 1, and perform the following calculations: Where P pv (t) is the distributed photovoltaic output power at time t, ψ a,τ (t) is the wavelet basis function, where a is the scale factor, τ is the shift factor, WT a,τ (t) is the energy decomposed from the distributed photovoltaic output power to the base coordinate axis; Reconstruction of N layer 2 N The power component P of the frequency band s (t), the power reconstruction process is as follows: Select the power component P s The low-frequency component P in (t) s，1 (t) as the combined power of light and energy storage; If the combined power of the photovoltaic and energy storage still does not meet the grid connection requirements, the wavelet packet decomposition layer number N is increased by one, and the wavelet packet decomposition and power reconstruction steps are repeated until the combined power of the photovoltaic and energy storage meets the grid connection requirements. At this time, the power component P s The sum of the remaining high-frequency components in (t) is P W (t) acts as energy storage to smooth power.

4. The autonomous comprehensive control method for distributed energy storage in medium and low voltage distribution networks according to claim 1, characterized in that: In S2, the distributed photovoltaic output power is smoothed based on the fluctuation smoothing method to obtain the photovoltaic energy storage combined power until the photovoltaic energy storage combined power meets the grid connection requirements, and then the specific method for calculating the energy storage smoothing power is as follows: The distributed photovoltaic output power is decomposed by the adaptive sliding average method with a smoothing window of M. The initial value of the smoothing window M is set to 1, and the following calculations are performed: P s，1 (t)=[P pv (t-M+1)+P pv (t-M+2)+…+P pv (t)] / M Where P s，1 (t) is the combined power of light and energy storage, P pv (t) is the distributed photovoltaic output power at time t, M is the suppression window; If the combined power of photovoltaic and energy storage still does not meet the grid connection requirements, the adaptive sliding average method will increase the smoothing window M by one, and the steps of the adaptive sliding average method will be repeated until the combined power of photovoltaic and energy storage meets the grid connection requirements. At this time, the difference P between the distributed photovoltaic output power and the combined power of photovoltaic and energy storage is calculated. W (t) is used as the energy storage smoothing power, and the formula is as follows: P W (t)=P pv (t)-P s，1 (t) Where P W (t) is the energy storage smoothing power.

5. The autonomous comprehensive control method for distributed energy storage in medium and low voltage distribution networks according to claim 1, characterized in that: In S4, the energy storage frequency regulation power is calculated according to different working conditions at each moment, and the method for adjusting the frequency deviation is as follows: Energy storage frequency modulation power P f (t) is calculated as follows: Where P pv (t) is the distributed photovoltaic output power at time t, P s，1 (t) is the combined power of photovoltaic power and energy storage, f max and f min are the upper and lower limits of the normal deviation of the system frequency, f H and f L are the upper and lower limits of the system frequency adjustment dead zone, K is the local frequency modulation coefficient, and f(t) is the system frequency at time t.

6. The autonomous comprehensive control method for distributed energy storage in medium and low voltage distribution networks according to claim 1, characterized in that: In S4, the energy storage frequency regulation power is calculated according to different working conditions at each moment as follows: Energy storage frequency modulation power P f (t) is calculated as follows: In the formula, k f is the active frequency modulation coefficient, P N is the energy storage rated power; f max and f min are the upper and lower limits of the normal deviation of the system frequency, f H and f L are the upper and lower limits of the dead zone range of the system frequency adjustment, f(t) is the system frequency at time t, and f N is the rated frequency of the system.

7. The autonomous comprehensive control method for distributed energy storage in medium and low voltage distribution networks according to claim 1, characterized in that: S5 is as follows: The reactive voltage regulation power of energy storage is calculated as follows: In the formula, Q U (t) is the reactive voltage regulation power of energy storage at time t, K U is the reactive voltage regulation coefficient of energy storage, U max , U min are the upper and lower limits of the allowable voltage range respectively, and U(t) is the local voltage at time t.

8. The autonomous comprehensive control method for distributed energy storage in medium and low voltage distribution networks according to claim 1, characterized in that: In S6, the calculation formula of the energy storage active autonomous comprehensive charging and discharging power is as follows: P ESS (t)=P W (t)+P f (t) Where P ESS (t) is the autonomous comprehensive charging and discharging power of energy storage active power P f (t) is the energy storage frequency modulation power, P W (t) is the energy storage smoothing power.

9. The autonomous comprehensive control method for distributed energy storage in medium and low voltage distribution networks according to claim 1, characterized in that: In S7, the calculation formula of the energy storage reactive autonomous comprehensive charging and discharging power is as follows: Q ESS (t)=Q U (t) In the formula, Q ESS (t) is the autonomous comprehensive charging and discharging power of energy storage reactive power, Q U (t) is the reactive voltage regulation power of energy storage at time t.

10. The autonomous comprehensive control method for distributed energy storage in medium and low voltage distribution networks according to claim 5, characterized in that: Upper limit of normal deviation of system frequency f max and the lower limit f min The values ​​of are 50.2Hz and 49.8Hz respectively, and the upper limit of the dead zone range of the system frequency adjustment is f H and the lower limit f L The values ​​are 50.03Hz and 49.97Hz respectively, and the local frequency modulation coefficient K ranges from 0.2 to 0.

5.

11. The autonomous comprehensive control method for distributed energy storage in medium and low voltage distribution networks according to claim 6, characterized in that: The active frequency modulation coefficient k f The value range is 5-50.

12. The autonomous comprehensive control method for distributed energy storage in medium and low voltage distribution networks according to claim 7, characterized in that: The specific value of the energy storage reactive voltage regulation coefficient is 21.

13. A distributed energy storage autonomous integrated control system for medium and low voltage distribution networks, characterized in that: include: A data acquisition module is used to obtain local data of a photovoltaic grid-connected point including a distributed photovoltaic distribution network; the local data includes: distributed photovoltaic output power, system frequency, local power fluctuation and local voltage; The power smoothing module is used to use the distributed photovoltaic output power as the photovoltaic energy storage combined power and determine whether it meets the grid connection requirements. If it meets the requirements, the photovoltaic energy is directly connected to the grid. If it does not meet the requirements, the distributed photovoltaic output power is smoothed based on the fluctuation smoothing method to obtain the photovoltaic energy storage combined power until the photovoltaic energy storage combined power meets the grid connection requirements, and then the energy storage smoothing power is calculated; the energy storage smoothing power is used to smooth the fluctuation of the distributed photovoltaic output power; The frequency adjustment module is used to divide the current system into multiple working conditions for analysis based on the system frequency and local power fluctuations, and calculate the energy storage frequency regulation power according to different working conditions at each moment to adjust the frequency deviation; the specific analysis of dividing the current system into multiple working conditions based on the system frequency and local power fluctuations is as follows: Based on system frequency and local power fluctuations, the analysis is divided into multiple operating conditions: ΔP pv =P pv (t-1)-P pv (t) Where ΔP pv is the power change, P pv (t) is the distributed photovoltaic output power at time t; When the system frequency f(t) is at the upper limit of the system frequency regulation dead zone f H To the lower limit of the system frequency adjustment dead zone f L In the frequency regulation dead zone, the energy storage system does not need to undertake the system frequency regulation task, but only needs to smooth the distributed photovoltaic output power based on the wavelet packet decomposition method; When the system frequency f(t) is at the lower limit f of the system frequency regulation dead zone at time t L To the lower limit of the normal deviation value of the system frequency f min When the energy storage system is between 200 and 250 km, it needs to take on the task of frequency regulation while smoothing the local fluctuations. The power change ΔP at this time will be calculated based on the energy storage smoothing power. pv Determine whether it is necessary to superimpose an energy storage frequency modulation power; When the system frequency f(t) is at the upper limit of the normal deviation value of the system frequency at time t max To the upper limit of the system frequency adjustment dead zone f H When the energy storage system is between 200 and 250 km, it needs to take on the task of frequency regulation while smoothing the local fluctuations. The power change ΔP at this time will be calculated based on the energy storage smoothing power. pv Determine whether it is necessary to superimpose an energy storage frequency modulation power; When the system frequency f(t) at time t is lower than the lower limit of the normal deviation of the system frequency f min If the energy storage smoothing power is used to control the energy storage charging, the energy storage smoothing power is directly set to 0; when the system frequency f(t) at time t is higher than the upper limit of the normal deviation value of the system frequency f max If the energy storage smoothing power is used to control the energy storage discharge, the energy storage smoothing power is directly set to 0; The voltage adjustment module is used to calculate the energy storage reactive voltage regulation power according to the local voltage at each moment, and is used to adjust the voltage deviation; The instruction calculation module determines the energy storage active autonomous comprehensive charging and discharging power by using the energy storage smoothing power and the energy storage frequency regulation power, and uses the energy storage active autonomous comprehensive charging and discharging power as the energy storage final active power charging and discharging instruction; determines the energy storage reactive autonomous comprehensive charging and discharging power by using the energy storage reactive voltage regulation power, and uses the energy storage reactive autonomous comprehensive charging and discharging power as the energy storage final reactive power charging and discharging instruction.

14. The distributed energy storage autonomous integrated control system for medium and low voltage distribution networks according to claim 13, characterized in that: The local data of the photovoltaic grid-connected point obtained is data on a time section.

15. The distributed energy storage autonomous integrated control system for medium and low voltage distribution networks according to claim 13, characterized in that: The specific method of calculating the distributed photovoltaic output power based on the fluctuation smoothing method to obtain the photovoltaic energy storage combined power until the photovoltaic energy storage combined power meets the grid connection requirements and then calculating the energy storage smoothing power is as follows: Perform N-layer wavelet packet decomposition on the distributed photovoltaic output power, set the initial value of the wavelet packet decomposition layer N to 1, and perform the following calculations: Where P pv (t) is the distributed photovoltaic output power at time t; ψ a,τ (t) is the wavelet basis function, where a is the scale factor, τ is the shift factor, WT a,τ (t) is the energy decomposed from the distributed photovoltaic output power to the base coordinate axis; Reconstruction of N layer 2 N The power component P of the frequency band s (t), the power reconstruction process is as follows: Select the power component P s The low-frequency component P in (t) s，1 (t) as the combined power of light and energy storage; If the combined power of the photovoltaic and energy storage still does not meet the grid connection requirements, the wavelet packet decomposition layer number N is increased by one, and the wavelet packet decomposition and power reconstruction steps are repeated until the combined power of the photovoltaic and energy storage meets the grid connection requirements. At this time, the power component P s The sum of the remaining high-frequency components in (t) is P W (t) acts as energy storage to smooth power.

16. The distributed energy storage autonomous integrated control system for medium and low voltage distribution networks according to claim 13, characterized in that: The specific method of calculating the distributed photovoltaic output power based on the fluctuation smoothing method to obtain the photovoltaic energy storage combined power until the photovoltaic energy storage combined power meets the grid connection requirements and then calculating the energy storage smoothing power is as follows: The distributed photovoltaic output power is decomposed by the adaptive sliding average method with a smoothing window of M. The initial value of the smoothing window M is set to 1, and the following calculations are performed: P s，1 (t)=[P pv (t-M+1)+P pv (t-M+2)+…+P pv (t)] / M Where P s，1 (t) is the combined power of light and energy storage, P pv (t) is the distributed photovoltaic output power at time t, M is the suppression window; If the combined power of photovoltaic and energy storage still does not meet the grid connection requirements, the adaptive sliding average method will increase the smoothing window M by one, and the steps of the adaptive sliding average method will be repeated until the combined power of photovoltaic and energy storage meets the grid connection requirements. At this time, the difference between the distributed photovoltaic output power and the combined power of photovoltaic and energy storage is P W (t) is used as the energy storage smoothing power, and the formula is as follows: P W (t)=P pv (t)-P s，1 (t) Where P W (t) is the energy storage smoothing power.

17. The distributed energy storage autonomous integrated control system for medium and low voltage distribution networks according to claim 13, characterized in that: The method for calculating the energy storage frequency modulation power according to different working conditions at each moment and adjusting the frequency deviation is as follows: Energy storage frequency modulation power P f (t) is calculated as follows: Where P pv (t) is the distributed photovoltaic output power at time t, P s，1 (t) is the combined power of photovoltaic power and energy storage, f max and f min are the upper and lower limits of the normal deviation of the system frequency, f H and f L are the upper and lower limits of the system frequency adjustment dead zone, K is the local frequency modulation coefficient, and f(t) is the system frequency at time t.

18. The distributed energy storage autonomous integrated control system for medium and low voltage distribution networks according to claim 13, characterized in that: The specific calculation of energy storage frequency modulation power according to different working conditions at each moment is: Energy storage frequency modulation power P f (t) is calculated as follows: In the formula, k f is the active frequency modulation coefficient, P N is the energy storage rated power; f max and f min are the upper and lower limits of the normal deviation of the system frequency, f H and f L are the upper and lower limits of the dead zone range of the system frequency adjustment, f(t) is the system frequency at time t, and f N is the rated frequency of the system.

19. The distributed energy storage autonomous integrated control system for medium and low voltage distribution networks according to claim 13, characterized in that: The calculation of the energy storage reactive voltage regulation power according to the local voltage at each moment is specifically as follows: The reactive voltage regulation power of energy storage is calculated as follows: In the formula, Q U (t) is the reactive voltage regulation power of energy storage at time t, K U is the reactive voltage regulation coefficient of energy storage, U max , U min are the upper and lower limits of the allowable voltage range respectively, and U(t) is the local voltage at time t.

20. The distributed energy storage autonomous integrated control system for medium and low voltage distribution networks according to claim 13, characterized in that: The calculation formula of the energy storage active autonomous comprehensive charging and discharging power is as follows: P ESS (t)=P W (t)+P f (t) Where P ESS (t) is the autonomous comprehensive charging and discharging power of energy storage active power, P f (t) is the energy storage frequency modulation power, P W (t) is the energy storage smoothing power.

21. The distributed energy storage autonomous integrated control system for medium and low voltage distribution networks according to claim 13, characterized in that: The calculation formula of the energy storage reactive autonomous comprehensive charging and discharging power is as follows: Q ESS (t)=Q U (t) In the formula, Q ESS (t) is the autonomous comprehensive charging and discharging power of energy storage reactive power, Q U (t) is the reactive voltage regulation power of energy storage at time t.

22. The distributed energy storage autonomous integrated control system for medium and low voltage distribution networks according to claim 17, characterized in that: Upper limit of normal deviation of system frequency f max and the lower limit f min The values ​​are 50.2Hz and 49.8Hz respectively, and the local frequency modulation coefficient K ranges from 0.2 to 0.

5.

23. The distributed energy storage autonomous integrated control system for medium and low voltage distribution networks according to claim 18, characterized in that: The active frequency modulation coefficient k f The value range is 5-50.

24. The distributed energy storage autonomous integrated control system for medium and low voltage distribution networks according to claim 19, characterized in that: The specific value of the energy storage reactive voltage regulation coefficient is 21.

25. An electronic device, characterized in that: include: A memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the method for autonomous integrated control of distributed energy storage in a medium and low voltage distribution network as described in any one of claims 1 to 12 is implemented.

26. A computer-readable storage medium storing a computer program, characterized in that: The computer program enables the computer to execute the autonomous comprehensive control method of distributed energy storage in medium and low voltage distribution networks as described in any one of claims 1-12.

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