Low-voltage transformer area energy storage coordination control low-voltage treatment method and system

Abstract

The invention relates to the technical field of low-voltage transformer area voltage quality treatment, and discloses a low-voltage transformer area energy storage coordination control low-voltage treatment method and system, and the method comprises the steps: monitoring the electrical parameters of a line in real time through a three-phase intelligent monitoring terminal; when it is monitored that the transformer area is low in voltage, collected abnormal voltage information is synchronously transmitted to a background control terminal; the background controller sends a low-voltage governance logic instruction to the mobile energy storage system; and after the energy storage system receives the instruction, switching low-voltage treatment logic according to requirements, and outputting active power and reactive power. The electrical parameters of the line are monitored in real time, and the system can rapidly and accurately detect the abnormal voltage condition of the low-voltage transformer area. And the background control terminal can immediately analyze the state of the power grid to ensure that the energy storage system can quickly respond when the voltage is abnormal. By dynamically adjusting the power output, the voltage of the transformer area can be effectively stabilized, and power supply quality reduction caused by too low voltage is prevented.

Description

Technical Field

[0001] The present invention relates to the technical field of voltage quality management in low-voltage substations, and specifically to a method and system for low-voltage management of energy storage coordinated control in low-voltage substations. Background Art

[0002] Voltage is one of the main measurement standards for power quality. It indirectly reflects the level of power system protection, operation, design and planning, and is very important in the technical and economic standards of power grid management. In recent years, distributed renewable energy power generation systems such as photovoltaic and wind power have become popular. As the scale of the power grid continues to expand, the power load has also increased, so that distribution network equipment in some areas cannot work normally to meet customer needs. The voltage fluctuation problem at the end of the distribution network line is becoming more and more serious, and voltage over-limit phenomenon often occurs. The voltage fluctuation problem not only threatens the stable operation of the power system, but also deeply affects the service life and work efficiency of the equipment.

[0003] The voltage problems at the end of the distribution network are generally divided into high voltage and low voltage. For the high voltage problem at the end of the medium and low distribution network, the main reasons are: the load power factor is too low; the large number of distributed power sources connected, the voltage is too high, it is easy to cause the electrical equipment to heat up, and even cause equipment damage, and affect the power transmission of the power grid to the load, and may cause the system to collapse. For the low voltage problem at the end of the medium and low distribution network, the main reasons are that the power load is obviously seasonal, scattered and far away from the power source, and the peak-to-valley difference is large; the line is long, the conductor cross-sectional area is insufficient, the power supply radius is large, and the three-phase imbalance is serious. The voltage is too low, which affects the normal operation of the equipment and shortens its service life, causing great economic losses to both users and power companies. Summary of the invention

[0004] In view of the above-mentioned problems, the present invention is proposed.

[0005] Therefore, the technical problem solved by the present invention is: how to solve the problem that the current low voltage problem in the substation area is difficult to manage and affects the regional power supply level.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions: a method for low voltage management by coordinated control of energy storage in a low voltage area, comprising:

[0007] Use three-phase intelligent monitoring terminal to monitor the electrical parameters of the line in real time;

[0008] When low voltage is detected in the substation area, the collected abnormal voltage information is synchronously transmitted to the background control terminal;

[0009] The background control sends low voltage management logic instructions to the mobile energy storage system;

[0010] After receiving the command, the energy storage system switches on the low voltage management logic as required to output active power and reactive power.

[0011] As a preferred solution of the low-voltage management method of coordinated control of low-voltage energy storage in the low-voltage substation described in the present invention, the electrical parameters of the monitoring line include: the three-phase intelligent monitoring terminal 1 is connected to the 0.4kV line and the mobile energy storage system wiring; the three-phase intelligent monitoring terminal 2 is installed at the 0.4kV outlet of the substation to monitor the electrical parameters of the line in real time.

[0012] As a preferred solution of the low-voltage management method of coordinated control of low-voltage energy storage in low-voltage substations described in the present invention, the monitoring of low voltage in the substation includes real-time sampling of voltage and current information. When low voltage is detected in the substation, the collected abnormal voltage information is synchronously transmitted to the background control terminal; after receiving the abnormal voltage information, the background control terminal analyzes and judges and sends low voltage management logic instructions to the mobile energy storage system.

[0013] As a preferred solution of the low-voltage area energy storage coordinated control low voltage management method described in the present invention, wherein: the mobile energy storage system includes a battery module, a battery management system, an energy management system, an energy storage inverter, a photovoltaic storage controller and a wireless signal transmission module; after receiving the instruction, the low voltage management logic is switched on and off according to the requirements, and the output of active power and reactive power is regulated to manage the low voltage in the area;

[0014] The voltage and current sampled in real time are expressed as follows for the voltage and current sampled values ​​at discrete time n:

[0015] V phase [n] = V m ·cos(ωnΔt+θ)

[0016] I phase [n]=I m ·cos(ωnΔt+θ I )

[0017] Among them, V phase [n] represents the phase voltage at the nth sampling point, I phase [n] represents the phase current at the nth sampling point, V m Indicates the maximum phase voltage, I m represents the maximum value of the phase current, ω represents the electrical angle frequency, n represents the current sampling sequence number, Δt represents the sampling interval time, θ represents the phase angle of the phase voltage, θ I Indicates the phase angle of the phase current;

[0018] Real-time active power P phase [n] The calculation formula at the nth sampling time:

[0019]

[0020] Among them, P phase [n] represents the phase active power corresponding to the nth sampling point, N represents the total number of sampling points used to calculate the average power, and cos(Φ[k]) represents the power factor corresponding to the kth sampling point;

[0021] Real-time reactive power Q phase [n] The calculation formula at the nth sampling time is expressed as:

[0022]

[0023] Among them, Q phase [n] represents the phase reactive power corresponding to the nth sampling point, and sin(Φ[k]) represents the sine value of the power factor angle corresponding to the kth sampling point.

[0024] As a preferred solution of the low voltage management method for coordinated control of low voltage energy storage in low voltage substations described in the present invention, the low voltage management logic includes the following specific steps:

[0025] When the single-phase voltage U≤U 限 , and the duration exceeds t minutes, it is judged that low voltage occurs;

[0026] Determine whether the energy storage system SOC is greater than D 限 %, if less than D 限 %, the energy storage system does not output power; if it is greater than or equal to D 限 %, then the next step is to determine whether the power factor cosΦ on the low-voltage side of the substation is less than the preset value X. If it is less than the preset value X, the reactive power gap is determined; if it is greater than or equal to the preset value X, the energy storage system outputs active power according to the remaining power;

[0027] Determine the reactive power gap. The energy storage system outputs reactive power at n1% of the rated power according to the reactive power gap for t minutes.

[0028] The calculation formula of SOC is expressed as:

[0029]

[0030] Among them, SOC(t) represents the charging state at time t, SOC(t0) represents the charging state at the initial time t0, C nominal represents the nominal capacity of the battery, I(t) represents the current at time t, t0 represents the initial time, and t represents the current time.

[0031] In practical applications, SOC is usually calculated by discrete time sampling data, and the numerical integration method is used to approximate SOC, and the formula is expressed as:

[0032]

[0033] Among them, SOC(t n ) represents the SOC at the nth time step; SOC(t n-1 ) represents the SOC at the n-1th time step; I(t n ) represents the current value at the nth time step; Δt represents the sampling time interval.

[0034] As a preferred solution of the low voltage management method of low voltage area energy storage coordinated control described in the present invention, the energy storage system stops outputting power when any of the three conditions is met. The three conditions specifically include: the phase voltage of the area is greater than U 限 , the output reactive power value is close to the rated power, and the power factor on the low-voltage side is greater than X; the energy storage system maintains reactive power output until the energy storage system SOC < D 限 %, the energy storage system stops outputting power;

[0035] When the above three conditions are not met, if the energy storage system SOC ≥ D 限 %, then output reactive power of n2% of rated power, maintain for T minutes, and execute in a loop until any of the three conditions is met, and return to execute to determine whether the power factor on the low-voltage side of the substation is less than the preset value X;

[0036] The energy storage system outputs active power at n2% of the remaining power for t minutes;

[0037] When one of the two conditions is met, the energy storage system maintains active power output; the two conditions include: the phase voltage in the substation is greater than U 限 , the output active power value is close to the residual power; when the energy storage system SOC is greater than D 限 %, the energy storage system stops outputting power;

[0038] When both conditions are not met, if the energy storage system SOC ≥ D 限 %, then increase the active power output by n4% of the remaining power and keep it for T minutes. Repeat the process until any of the three conditions is met.

[0039] As a preferred solution of the low voltage management method of low voltage area energy storage coordinated control described in the present invention, wherein: the output of active power and reactive power includes, the calculation method for determining the reactive power gap is:

[0040] Q 缺=(X0-cosΦ)*S

[0041] Among them, Q 缺 It represents the reactive power gap value, X0 represents the power factor limit value on the low-voltage side of the substation, cosΦ represents the power factor on the low-voltage side of the substation, and S represents the apparent power value on the low-voltage side of the substation; the specific values ​​of cosΦ and S are obtained through real-time monitoring of the three-phase intelligent monitoring terminal 2.

[0042] A low voltage management system for low voltage area energy storage coordinated control using any method described in the present invention, wherein:

[0043] The mobile energy storage system module includes battery modules, battery management system, energy management system, energy storage inverter, photovoltaic storage controller and wireless signal transmission module. The mobile energy storage system is connected to the 0.4kV outgoing line of the substation and has low voltage management logic function.

[0044] The background control terminal module respectively transmits wireless signals with the mobile energy storage system, the three-phase voltage monitoring terminal 1, and the three-phase intelligent monitoring terminal 2 and issues task instructions to them;

[0045] The three-phase intelligent monitoring terminal module includes an electric energy information acquisition module, an information analysis module, a power supply module, a wireless signal transmission module and a fault information early warning module, which is connected to the 0.4kV line and the mobile energy storage system wiring, and is used to monitor the power information output by the energy storage system in real time and transmit it to the background control terminal in real time;

[0046] The three-phase intelligent monitoring terminal module includes an electric energy information acquisition module, an information analysis module, a power supply module and a wireless signal transmission module. The three-phase intelligent monitoring terminal 2 is connected to the 0.4kV low-voltage side outlet of the line and is used to monitor the three-phase voltage, current, active power, reactive power, power factor, apparent power and other electrical parameter information in the line in real time. When a low voltage situation is detected, the electrical parameter information is transmitted to the background control terminal in real time.

[0047] A computer device comprises: a memory and a processor; the memory stores a computer program, comprising: the steps of implementing any one of the methods of the present invention when the processor executes the computer program.

[0048] A computer-readable storage medium stores a computer program, comprising: when the computer program is executed by a processor, the steps of implementing any one of the methods of the present invention are implemented.

[0049] Beneficial effects of the present invention: The present invention monitors the electrical parameters of the line in real time, and the system can quickly and accurately detect voltage anomalies in low-voltage areas. The background control terminal can immediately analyze the state of the power grid to ensure that the energy storage system can respond quickly when voltage anomalies occur. By dynamically adjusting the power output, the voltage in the area can be effectively stabilized to prevent the power supply quality from being reduced due to low voltage. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. Among them:

[0051] Figure 1 An overall flow chart of a method for low voltage management provided by a low voltage area energy storage coordinated control according to the first embodiment of the present invention;

[0052] Figure 2 A schematic diagram of the structure of a low voltage management method for coordinated control of low voltage by energy storage in a low voltage area provided by the second embodiment of the present invention;

[0053] Figure 3 A structural diagram of the components of a low-voltage area energy storage coordinated control low-voltage management method provided for the second embodiment of the present invention. DETAILED DESCRIPTION

[0054] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the drawings of the specification. Obviously, the described embodiments are part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in the art without creative work should fall within the scope of protection of the present invention.

[0055] Example 1, reference Figure 1 , which is an embodiment of the present invention, provides a method for low voltage management by coordinated control of energy storage in a low voltage area, comprising:

[0056] S1: Use the three-phase intelligent monitoring terminal to monitor the electrical parameters of the line in real time.

[0057] Furthermore, the electrical parameters of the monitoring line include: the three-phase intelligent monitoring terminal 1 is connected to the 0.4kV line and the mobile energy storage system wiring; the three-phase intelligent monitoring terminal 2 is installed at the 0.4kV outgoing line of the substation to monitor the electrical parameters of the line in real time.

[0058] It should be noted that three-phase intelligent monitoring terminals are widely used in the electrical parameter monitoring of low-voltage distribution networks. These terminals can collect electrical parameters including voltage, current, active power, reactive power, power factor, etc., and transmit these data to the background control system. Based on these data, the background control system can determine the operating status of the power grid and start the mobile energy storage system for voltage management when necessary.

[0059] S2: When low voltage is detected in the substation, the collected abnormal voltage information is synchronously transmitted to the background control terminal.

[0060] Furthermore, the monitoring of low voltage in the substation includes real-time sampling of voltage and current information. When low voltage is detected in the substation, the collected abnormal voltage information is synchronously transmitted to the background control terminal; after receiving the abnormal voltage information, the background control terminal analyzes and judges and sends low voltage management logic instructions to the mobile energy storage system.

[0061] Furthermore, in low-voltage distribution networks, voltage stability is one of the important factors affecting power supply quality. Especially during peak hours or long-distance power transmission, the voltage at the end user is prone to drop, resulting in unstable equipment operation or reduced efficiency. By deploying a three-phase intelligent monitoring terminal, accurate monitoring of the electrical parameters of the substation can be achieved, and the low voltage problem can be effectively managed through the dynamic response of the mobile energy storage system.

[0062] Furthermore, three-phase current measurement: Each monitoring terminal measures the three-phase current I a ,I b ,I c , used to calculate power and analyze load conditions.

[0063] For any phase current I phase :

[0064] I phase =I m ·cos(ωt+θ I

[0065] Among them, I m is the amplitude of the phase current. ·θ I is the phase angle of the current.

[0066] Active power monitoring, calculates active power P based on the measured voltage and current, and the formula is expressed as:

[0067]

[0068] Among them, U line is the line voltage, I lineis the line current, cos(Φ) is the power factor. Reactive power calculation, calculate the reactive power Q based on the measured voltage and current:

[0069]

[0070] Furthermore, sin(Φ) is the sine of the power factor angle.

[0071] It should be noted that by deploying three-phase intelligent monitoring terminals, the electrical parameters in the line can be monitored in real time, providing data support for the stable operation of the power grid. It can significantly improve the operating stability and power supply quality of the distribution network, and also lay the foundation for the construction of smart grids.

[0072] S3: The background control sends low voltage management logic instructions to the mobile energy storage system.

[0073] Furthermore, the mobile energy storage system includes a battery module, a battery management system, an energy management system, an energy storage inverter, a photovoltaic storage controller and a wireless signal transmission module; after receiving the instruction, the low voltage management logic is switched on and off as required, the output of active power and reactive power is regulated, and the low voltage in the substation is managed.

[0074] Furthermore, the voltage and current sampled in real time are expressed as follows for the voltage and current sampled values ​​at discrete time n:

[0075] V phase [n] = V m ·cos(ωnΔt+θ)

[0076] I phase [n]=I m ·cos(ωnΔt+θ I )

[0077] Among them, V phase [n] represents the phase voltage at the nth sampling point, I phase [n] represents the phase current at the nth sampling point, V m Indicates the maximum phase voltage, I m represents the maximum value of the phase current, ω represents the electrical angle frequency, n represents the current sampling sequence number, Δt represents the sampling interval time, θ represents the phase angle of the phase voltage, θ I Indicates the phase angle of the phase current.

[0078] Furthermore, the real-time active power P phase [n] The calculation formula at the nth sampling time:

[0079]

[0080] Among them, P phase[n] represents the phase active power corresponding to the nth sampling point, N represents the total number of sampling points used to calculate the average power, and cos(Φ[k]) represents the power factor corresponding to the kth sampling point.

[0081] Furthermore, the real-time reactive power Q phase [n] The calculation formula at the nth sampling time is expressed as:

[0082]

[0083] Among them, Q phase [n] represents the phase reactive power corresponding to the nth sampling point, and sin(Φ[k]) represents the sine value of the power factor angle corresponding to the kth sampling point.

[0084] It should be noted that the battery module is a basic unit for storing electrical energy, usually composed of lithium-ion batteries or other high-energy density batteries. Battery Management System (BMS): used to monitor and manage the status of the battery module, including parameters such as voltage, temperature, and current, to ensure the safe and efficient operation of the battery. Energy Management System (EMS): responsible for the optimal scheduling and control of the overall energy, and through communication with the background control terminal, regulates the output of active power and reactive power according to a predetermined logic. Energy Storage Inverter (PCS): converts DC power into AC power, and can switch between grid-connected and off-grid modes to ensure that the energy storage system can flexibly respond to various grid requirements. Photovoltaic storage controller: used to control the coordinated work of the photovoltaic power generation system and the energy storage system, and optimize the utilization and storage of photovoltaic energy. Wireless signal transmission module: used to receive instructions from the background control terminal, and transmit real-time monitoring data back to the background to ensure the coordination and linkage of the system.

[0085] S4: After receiving the command, the energy storage system switches on the low voltage management logic as required to output active power and reactive power.

[0086] Furthermore, the low voltage management logic includes, wherein the specific steps of the low voltage management logic include:

[0087] Furthermore, when a single-phase voltage U≤U 限 , and the duration exceeds t minutes, it is judged that low voltage occurs.

[0088] Furthermore, it is determined whether the energy storage system SOC is greater than D 限 %, if less than D 限 %, the energy storage system does not output power; if it is greater than or equal to D 限 %, then the next step is to determine whether the power factor cosΦ on the low-voltage side of the substation is less than the preset value X. If it is less than the preset value X, the reactive power gap is determined; if it is greater than or equal to the preset value X, the energy storage system outputs active power according to the remaining power.

[0089] Furthermore, the reactive power gap is determined, and the energy storage system outputs reactive power according to n1% of the rated power for t minutes based on the reactive power gap.

[0090] Furthermore, the calculation formula of SOC is expressed as:

[0091]

[0092] Among them, SOC(t) represents the charging state at time t, SOC(t0) represents the charging state at the initial time t0, C nominal represents the nominal capacity of the battery, I(t) represents the current at time t, t0 represents the initial time, and t represents the current time.

[0093] Furthermore, in practical applications, SOC is usually calculated by discrete time sampling data, and the numerical integration method is used to approximate SOC, which is expressed as:

[0094]

[0095] Among them, SOC(t n ) represents the SOC at the nth time step; SOC(t n-1 ) represents the SOC at the n-1th time step; I(t n ) represents the current value at the nth time step; Δt represents the sampling time interval.

[0096] Furthermore, in order to determine whether the energy storage system can participate in low voltage management operations, the SOC determination condition is usually whether the SOC reaches the set lower limit value D limit .

[0097] Furthermore, if SOC(t n )≥D limit Then power output can be performed; D limit Usually set by the system, it indicates the minimum allowable SOC percentage of the energy storage system; the complete formula of the SOC determination model is expressed as:

[0098]

[0099] Among them, SOC(t n ) indicates that at the current time t n SOC value; SOC(t0) represents the initial SOC value; I(t k ) means that at each sampling point t k The current value. Δt represents the sampling time interval. limit Indicates the lower threshold of SOC.

[0100] Furthermore, the low voltage management logic also includes that when any of the three conditions is met, the energy storage system stops outputting power. The three conditions specifically include: the phase voltage in the substation is greater than U 限 , the output reactive power value is close to the rated power, and the power factor on the low-voltage side is greater than X; the energy storage system maintains reactive power output until the energy storage system SOC < D 限 %, the energy storage system stops outputting power.

[0101] Furthermore, when the above three conditions are not met, if the energy storage system SOC ≥ D 限 %, then output reactive power of n2% of rated power, maintain for T minutes, and execute in a loop until any of the three conditions is met, and return to execute to determine whether the power factor on the low-voltage side of the substation is less than the preset value X;

[0102] Furthermore, the energy storage system outputs active power according to n2% of the remaining power for t minutes.

[0103] Furthermore, the energy storage system maintains active power output when one of the two conditions is met; the two conditions include that the phase voltage in the substation is greater than U 限 , the output active power value is close to the residual power; when the energy storage system SOC is greater than D 限 %, the energy storage system stops outputting power.

[0104] Furthermore, when both conditions are not met, if the energy storage system SOC ≥ D 限 %, then increase the active power output by n4% of the remaining power and keep it for T minutes. Repeat the process until any of the three conditions is met.

[0105] Furthermore, the output of active power and reactive power includes: the reactive power gap calculation method is:

[0106] Q 缺 =(X0-cosΦ)*S

[0107] Among them, Q 缺 It represents the reactive power gap value, X0 represents the power factor limit value on the low-voltage side of the substation, cosΦ represents the power factor on the low-voltage side of the substation, and S represents the apparent power value on the low-voltage side of the substation; the specific values ​​of cosΦ and S are obtained through real-time monitoring of the three-phase intelligent monitoring terminal 2.

[0108] It should be noted that the multi-level low voltage management logic and the further improved low voltage management logic should consider multi-level control strategies to deal with voltage anomalies of different degrees. Graded response mechanism: According to the severity of the voltage anomaly, the energy storage system can take different levels of response measures. Mild voltage deviation: The energy storage system first fine-tunes by adjusting the reactive power. Moderate voltage deviation: When the reactive power adjustment is not enough to restore the voltage, the energy storage system starts the active power output for stronger voltage regulation. Severe voltage anomaly: If the above measures cannot restore the voltage to normal levels, the system can trigger an emergency response, which may include load transfer, load shedding or increasing the output power of the energy storage system. Dynamic adjustment of control parameters: The energy storage system should dynamically adjust the control parameters (such as power factor setpoint, output power proportional coefficient, etc.) according to the real-time monitored electrical parameters to adapt to changes in grid load and voltage fluctuations.

[0109] On the other hand, this embodiment also provides a low voltage management system for coordinated control of low voltage energy storage in a low voltage area, which includes:

[0110] The mobile energy storage system module includes battery modules, battery management system, energy management system, energy storage inverter, photovoltaic storage controller and wireless signal transmission module. The mobile energy storage system is connected to the 0.4kV outgoing line of the substation and has low voltage management logic function.

[0111] The background control terminal module respectively transmits wireless signals with the mobile energy storage system, the three-phase voltage monitoring terminal 1, and the three-phase intelligent monitoring terminal 2 and issues task instructions to them.

[0112] The three-phase intelligent monitoring terminal module includes an electric energy information acquisition module, an information analysis module, a power supply module, a wireless signal transmission module and a fault information warning module. It is connected to the 0.4kV line and the mobile energy storage system wiring to monitor the power information output by the energy storage system in real time and transmit it to the background control terminal in real time.

[0113] The three-phase intelligent monitoring terminal module includes an electric energy information acquisition module, an information analysis module, a power supply module and a wireless signal transmission module. The three-phase intelligent monitoring terminal 2 is connected to the 0.4kV low-voltage side outlet of the line and is used to monitor the three-phase voltage, current, active power, reactive power, power factor, apparent power and other electrical parameter information in the line in real time. When a low voltage situation is detected, the electrical parameter information is transmitted to the background control terminal in real time.

[0114] If the above functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program codes.

[0115] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute instructions), or in conjunction with such instruction execution systems, devices or apparatuses. For the purposes of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in conjunction with such instruction execution systems, devices or apparatuses.

[0116] More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection with one or more wires (electronic device), a portable computer disk case (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be a paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, deciphering or, if necessary, processing in another suitable manner, and then stored in a computer memory.

[0117] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, a plurality of steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0118] Example 2, reference Figure 2 and Figure 3 , which is an embodiment of the present invention, provides a method for low-voltage management by coordinated control of energy storage in a low-voltage area. In order to verify the beneficial effects of the present invention, scientific demonstration is carried out through economic benefit calculation and simulation experiments.

[0119] See also Figures 2 to 3 , which is a structural schematic diagram and method flow chart of a low-voltage area energy storage coordinated control low-voltage management system provided by the present invention. Taking the low voltage situation of phase A of the 400V side line of the area as an example, the U limit is set to 198V, t is 5 minutes, T is 3 minutes, D limit% is 10%, and the preset value X is 0.8. According to the present invention, the three-phase intelligent monitoring terminal 2 is installed at the 0.4kV outlet of the area to monitor the electrical parameters of the line. When the low voltage situation in the area is detected, the collected abnormal voltage information is synchronously transmitted to the background control terminal. After receiving the abnormal voltage information, the background control terminal sends a low voltage management logic instruction to the mobile energy storage system after analysis and judgment; after receiving the instruction, the mobile energy storage system switches the low voltage management logic as required to output active power and reactive power, thereby managing the low voltage in the area; the low voltage management method specifically includes the following steps:

[0120] The three-phase intelligent monitoring terminal 2 was installed at the 0.4kV outgoing line of the substation area. It was detected that the voltage amplitude of phase A was below 198V for more than 5 minutes, and it was judged that low voltage occurred.

[0121] At this time, the SOC of the energy storage system is 73%, which is greater than the D limit. Further, it is determined whether the power factor cosΦ on the low-voltage side of the substation is less than 0.9.

[0122] According to the electrical parameter information data collected by the three-phase intelligent monitoring terminal 2, it can be seen that the power factor on the low-voltage side of the substation is 0.8, which is less than the preset value of 0.9. At the same time, the apparent power value on the low-voltage side of the substation is

[0123] Furthermore, the reactive power gap is determined. At this time, the reactive power gap is calculated as follows:

[0124]

[0125] Furthermore, the energy storage system outputs reactive power at n1% of the rated power according to the reactive power gap for 5 minutes;

[0126] Furthermore, according to the power factor data collected by the three-phase intelligent monitoring terminal 2, the power factor on the low-voltage side is 0.92 at this time, but the phase A voltage in the substation is still less than 198V, and the energy storage system maintains the current reactive power output;

[0127] Furthermore, the energy storage system outputs active power at n3% of the remaining power for 5 minutes. At this time, the phase A voltage of the substation is still less than 198V, and the output active power value is not close to the remaining power.

[0128] Furthermore, if the SOC of the energy storage system is ≥ 10% at this time, the active power output is increased by n4% of the residual power, and maintained for 3 minutes, and the cycle is executed until the phase A voltage of the substation is greater than 198V or the output active power value is close to the residual power;

[0129] Furthermore, the energy storage system maintains the current active power output. When the SOC of the energy storage system is less than 10%, the energy storage system stops outputting power and completes the low voltage management in the substation.

[0130] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for low voltage management by coordinated control of energy storage in low voltage areas, characterized in that: include: Use three-phase intelligent monitoring terminal to monitor the electrical parameters of the line in real time; When low voltage is detected in the substation area, the collected abnormal voltage information is synchronously transmitted to the background control terminal; The background control sends low voltage management logic instructions to the mobile energy storage system; After receiving the command, the energy storage system switches on the low voltage management logic as required to output active power and reactive power.

2. The method for low voltage management by coordinated control of energy storage in low voltage areas according to claim 1, characterized in that: The electrical parameters of the monitoring line include: the three-phase intelligent monitoring terminal 1 is connected to the 0.4kV line and the mobile energy storage system connection; the three-phase intelligent monitoring terminal 2 is installed at the 0.4kV outgoing line of the substation to monitor the electrical parameters of the line in real time.

3. The method for low voltage management by coordinated control of energy storage in low voltage areas according to claim 2, characterized in that: The monitoring of low voltage in the substation includes real-time sampling of voltage and current information, and when low voltage in the substation is detected, synchronously transmitting the collected abnormal voltage information to the background control terminal; After receiving the abnormal voltage information, the background control terminal analyzes and judges it, and then sends the low voltage management logic instruction to the mobile energy storage system.

4. The method for low voltage management by coordinated control of energy storage in low voltage areas according to claim 3, characterized in that: The mobile energy storage system includes a battery module, a battery management system, an energy management system, an energy storage inverter, a photovoltaic storage controller and a wireless signal transmission module; after receiving the instruction, the low voltage management logic is switched on and off according to the requirements, and the output of active power and reactive power is adjusted to manage the low voltage in the substation area; The voltage and current sampled in real time are expressed as follows for the voltage and current sampled values ​​at discrete time n: V phase [n]=V m ·cos(ωnΔt+θ) I phase [n]=I m ·cos(ωnΔt+θ I ) Among them, V phase [n] represents the phase voltage at the nth sampling point, I phase [n] represents the phase current at the nth sampling point, V m Indicates the maximum phase voltage, I m represents the maximum value of the phase current, ω represents the electrical angle frequency, n represents the current sampling sequence number, Δt represents the sampling interval time, θ represents the phase angle of the phase voltage, θ I Indicates the phase angle of the phase current; Real-time active power P phase [n] The calculation formula at the nth sampling time: Among them, P phase [n] represents the phase active power corresponding to the nth sampling point, N represents the total number of sampling points used to calculate the average power, and cos(Φ[k]) represents the power factor corresponding to the kth sampling point; Real-time reactive power Q phase [n] The calculation formula at the nth sampling time is expressed as: Among them, Q phase [n] represents the phase reactive power corresponding to the nth sampling point, and sin(Φ[k]) represents the sine value of the power factor angle corresponding to the kth sampling point.

5. The method for low voltage management by coordinated control of energy storage in low voltage areas according to claim 4, characterized in that: The low voltage management logic includes, wherein the specific steps of the low voltage management logic include: When the single-phase voltage U≤U 限 , and the duration exceeds t minutes, it is judged that low voltage occurs; Determine whether the energy storage system SOC is greater than D 限 %, if less than D 限 %, the energy storage system does not output power; if it is greater than or equal to D 限 %, then the next step is to determine whether the power factor cosΦ on the low-voltage side of the substation is less than the preset value X. If it is less than the preset value X, the reactive power gap is determined; if it is greater than or equal to the preset value X, the energy storage system outputs active power according to the remaining power; Determine the reactive power gap. The energy storage system outputs reactive power at n1% of the rated power according to the reactive power gap for t minutes. The calculation formula of SOC is expressed as: Among them, SOC(t) represents the charging state at time t, SOC(t0) represents the charging state at the initial time t0, C nominal represents the nominal capacity of the battery, I(t) represents the current at time t, t0 represents the initial time, and t represents the current time; In practical applications, SOC is usually calculated by discrete time sampling data, and the numerical integration method is used to approximate SOC, and the formula is expressed as: Among them, SOC(t n ) represents the SOC at the nth time step; SOC(t n-1 ) represents the SOC at the n-1th time step; I(t n ) represents the current value at the nth time step; Δt represents the sampling time interval.

6. The method for low voltage management by coordinated control of energy storage in low voltage areas according to claim 5, characterized in that: The low voltage management logic also includes that when any of the three conditions is met, the energy storage system stops outputting power. The three conditions specifically include: the phase voltage in the substation is greater than U 限 , the output reactive power value is close to the rated power, and the power factor on the low-voltage side is greater than X; the energy storage system maintains reactive power output until the energy storage system SOC < D 限 %, the energy storage system stops outputting power; When the above three conditions are not met, if the energy storage system SOC ≥ D 限 %, then output reactive power of n2% of rated power, maintain for T minutes, and execute in a loop until any of the three conditions is met, and return to execute to determine whether the power factor on the low-voltage side of the substation is less than the preset value X; The energy storage system outputs active power at n2% of the remaining power for t minutes; When one of the two conditions is met, the energy storage system maintains active power output; the two conditions include: the phase voltage in the substation is greater than U 限 , the output active power value is close to the residual power; when the energy storage system SOC is greater than D 限 %, the energy storage system stops outputting power; When both conditions are not met, if the energy storage system SOC ≥ D 限 %, then increase the active power output by n4% of the remaining power and keep it for T minutes. Repeat the process until any of the three conditions is met.

7. The method for low voltage management by coordinated control of energy storage in low voltage areas according to claim 6, characterized in that: The output of active power and reactive power includes: the reactive power gap calculation method is as follows: Q 缺 =(X0-cosΦ)*S Among them, Q 缺 It represents the reactive power gap value, X0 represents the power factor limit value on the low-voltage side of the substation, cosΦ represents the power factor on the low-voltage side of the substation, and S represents the apparent power value on the low-voltage side of the substation; the specific values ​​of cosΦ and S are obtained through real-time monitoring of the three-phase intelligent monitoring terminal 2.

8. A low voltage management system for low voltage area energy storage coordinated control using the method as described in any one of claims 1 to 7, characterized in that: The mobile energy storage system module includes battery modules, battery management system, energy management system, energy storage inverter, photovoltaic storage controller and wireless signal transmission module. The mobile energy storage system is connected to the 0.4kV outgoing line of the substation and has low voltage management logic function. The background control terminal module respectively transmits wireless signals with the mobile energy storage system, the three-phase voltage monitoring terminal 1, and the three-phase intelligent monitoring terminal 2 and issues task instructions to them; The three-phase intelligent monitoring terminal 1 module includes an electric energy information acquisition module, an information analysis module, a power supply module, a wireless signal transmission module and a fault information early warning module, which is connected to the 0.4kV line and the mobile energy storage system wiring, and is used to monitor the power information output by the energy storage system in real time and transmit it to the background control terminal in real time; The three-phase intelligent monitoring terminal 2 module includes an electric energy information acquisition module, an information analysis module, a power supply module and a wireless signal transmission module. The three-phase intelligent monitoring terminal 2 is connected to the 0.4kV low-voltage side outlet of the line and is used to monitor the three-phase voltage, current, active power, reactive power, power factor, apparent power and other electrical parameter information in the line in real time. When a low voltage situation is detected, the electrical parameter information is transmitted to the background control terminal in real time.

9. A computer device comprising: A memory and a processor; the memory stores a computer program, characterized in that: when the processor executes the computer program, the steps of the low-voltage management method for coordinated control of low-voltage energy storage in a low-voltage area are implemented as described in any one of claims 1-7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by the processor, the steps of the low voltage management method for coordinated control of low voltage by energy storage in a low voltage area are implemented as described in any one of claims 1-7.

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