A control method, device, equipment, medium and product for a decentralized energy storage system in rural power distribution networks

Abstract

The present application discloses a control method, device, equipment, medium and product for a distributed energy storage system in rural power distribution networks, relating to the technical field of optimized operation of energy storage systems. The method includes: obtaining the power values of each time period within a day according to the typical daily load curve of the target rural power distribution substation area; if the power value within the time period is greater than the set threshold, the target rural power distribution substation area executes the substation area autonomous mode within the time period; if it is not greater than the set threshold, the aggregated energy storage mode is executed within the time period. The aggregated energy storage mode is: if there is a state of charge less than the target value among the states of charge of all energy storage units, control the intermediate group of energy storage units and the main discharge unit to discharge to the main charging unit and the load; if the states of charge of all energy storage units are greater than the target value, control all energy storage units to discharge to the load. The present application can relieve heavy overload, improve low voltage, reduce unbalance, meet power supply guarantee in multiple scenarios, and solve the problem of reverse power flow of photovoltaic power in rural power distribution substations.

Description

Technical Field

[0001] The present application relates to the technical field of optimized operation of energy storage systems, and particularly to a control method, device, equipment, medium and product for a decentralized energy storage system in rural distribution networks. Background Art

[0002] With the continuous acceleration of the pace of new rural construction, the rural electricity demand continues to grow, the scale of rural distribution networks is also increasing, and the requirements for the power supply safety and quality of rural distribution networks are rising day by day. However, from the actual situation at the present stage, the overall technical level of rural distribution networks lags behind relatively, and there are mainly the following problems: power reverse injection caused by disordered input of distributed photovoltaics; time-periodic heavy overloads caused by an increase in time-sharing adjustable loads; severe voltage conditions, especially low voltage at the end and three-phase imbalance; and enhanced demand for power supply guarantee in multiple scenarios.

[0003] Therefore, there is an urgent need for a control method for a decentralized energy storage system in rural distribution networks that can relieve heavy overloads, improve low voltage, reduce imbalance, meet the power supply guarantee in multiple scenarios, and solve the problem of photovoltaic power reverse injection in rural distribution substations. Summary of the Invention

[0004] The purpose of the present application is to provide a control method, device, equipment, medium and product for a decentralized energy storage system in rural distribution networks, which can relieve heavy overloads, improve low voltage, reduce imbalance, meet the power supply guarantee in multiple scenarios, and solve the problem of photovoltaic power reverse injection in rural distribution substations.

[0005] To achieve the above purpose, the present application provides the following solutions:

[0006] In a first aspect, the present application provides a control method for a decentralized energy storage system in rural distribution networks, including:

[0007] Obtain the typical daily load curve of the target rural distribution substation;

[0008] Obtain the power values of each time period within a day of the target rural distribution substation according to the typical daily load curve of the target rural distribution substation;

[0009] For any time period within a day of the target rural distribution substation, if the power value within the time period of the target rural distribution substation within a day is greater than a set threshold, the target rural distribution substation executes the substation autonomous mode within the time period;

[0010] If the power value within the time period of the target rural distribution substation within a day is not greater than the set threshold, the target rural distribution substation executes the aggregated energy storage mode within the time period;

[0011] The aggregated energy storage mode is:

[0012] If there is a state of charge less than the target value among the states of charge of all energy storage units in the target rural power distribution substation at the current moment, then control the main discharge unit at the current moment to operate in the constant voltage control mode, the intermediate group of energy storage units at the current moment and the main charging unit at the current moment to operate in the power control mode, and the intermediate group of energy storage units at the current moment and the main discharge unit at the current moment to discharge to the main charging unit and the load at the current moment; the main discharge unit is the energy storage unit with the largest state of charge among all energy storage units in the target rural power distribution substation; the main charging unit is the energy storage unit with the smallest state of charge among all energy storage units in the target rural power distribution substation; the intermediate group of energy storage units is all energy storage units in the target rural power distribution substation except the main discharge unit and the main charging unit; the constant voltage control mode means that the output voltage remains unchanged; the power control mode is to operate according to the power command.

[0013] If the states of charge of all energy storage units in the target rural power distribution substation at the current moment are all greater than the target value, then control all energy storage units in the target rural power distribution substation at the current moment to discharge to the load, the main discharge unit at the current moment to operate in the constant voltage control mode, and the intermediate group of energy storage units at the current moment and the main charging unit at the current moment to operate in the power control mode.

[0014] Optionally, obtaining the power values of each time period within a day in the target rural power distribution substation according to the typical daily load curve of the target rural power distribution substation specifically includes:

[0015] Perform multiple predictions on the typical daily load curve of the target rural power distribution substation to obtain multiple predicted curves of the typical daily load curve of the target rural power distribution substation;

[0016] Cluster the multiple predicted curves of the typical daily load curve of the target rural power distribution substation to obtain the power values of each time period within a day in the target rural power distribution substation.

[0017] Optionally, controlling the intermediate group of energy storage units at the current moment to operate in the power control mode specifically includes:

[0018] Calculate the electricity quantity of each energy storage unit in the target rural power distribution substation at the current moment based on the state of charge of each energy storage unit in the target rural power distribution substation at the current moment;

[0019] Calculate the time required for the target rural power distribution substation to reach the equilibrium state based on the electricity quantity of each energy storage unit in the target rural power distribution substation at the current moment, the charging power of the main charging unit at the current moment, and the load power of the target rural power distribution substation at the current moment;

[0020] Calculate the power command of each energy storage unit in the intermediate group of energy storage units based on the electricity quantity of each energy storage unit in the target rural power distribution substation at the current moment, the load power of the target rural power distribution substation at the current moment, and the time required for the target rural power distribution substation to reach the equilibrium state.

[0021] Optionally, calculate the power commands of each energy storage unit in the intermediate group of energy storage units based on the current power of each energy storage unit in the target rural power distribution substation area, the load power of the target rural power distribution substation area at the current moment, and the time required for the target rural power distribution substation area to reach the balanced state. Specifically, it includes:

[0022] According to the formula Calculate the power command of the nth energy storage unit in the intermediate group of energy storage units, where P n Represents the power command of the nth energy storage unit in the intermediate group of energy storage units, P load Represents the load power of the target rural power distribution substation area at the current moment, E n Represents the current power of the nth energy storage unit in the target rural power distribution substation area, T b Represents the time required for the target rural power distribution substation area to reach the balanced state, and N represents the total number of energy storage units in the target rural power distribution substation area.

[0023] In a second aspect, the present application provides a control device for a distributed energy storage system in a rural power distribution network, including:

[0024] An acquisition module, configured to acquire the typical daily load curve of the target rural power distribution substation area;

[0025] A power calculation module, configured to obtain the power values of each time period within a day of the target rural power distribution substation area according to the typical daily load curve of the target rural power distribution substation area;

[0026] A substation area autonomous mode execution module, configured to, for any time period within a day of the target rural power distribution substation area, if the power value within the time period of the target rural power distribution substation area within a day is greater than a set threshold, then the target rural power distribution substation area executes the substation area autonomous mode within the time period;

[0027] An aggregated energy storage mode execution module, configured to, if the power value within the time period of the target rural power distribution substation area within a day is not greater than a set threshold, then the target rural power distribution substation area executes the aggregated energy storage mode within the time period;

[0028] The aggregated energy storage mode is:

[0029] If there is a state of charge less than the target value among the states of charge of all energy storage units in the target rural power distribution substation area at the current moment, then control the main discharge unit at the current moment to operate in the constant voltage control mode, the intermediate group of energy storage units at the current moment and the main charging unit at the current moment to operate in the power control mode, and the intermediate group of energy storage units at the current moment and the main discharge unit at the current moment discharge to the main charging unit and the load at the current moment; the main discharge unit is the energy storage unit with the largest state of charge among all energy storage units in the target rural power distribution substation area; the main charging unit is the energy storage unit with the smallest state of charge among all energy storage units in the target rural power distribution substation area; the intermediate group of energy storage units is all energy storage units in the target rural power distribution substation area except the main discharge unit and the main charging unit; the constant voltage control mode means that the output voltage remains unchanged; the power control mode is to operate according to the power command.

[0030] If the states of charge of all energy storage units in the target rural power distribution substation area at the current moment are all greater than the target value, then control all energy storage units in the target rural power distribution substation area at the current moment to discharge to the load, the main discharge unit at the current moment to operate in the constant voltage control mode, and the intermediate group of energy storage units at the current moment and the main charging unit at the current moment to operate in the power control mode.

[0031] In a third aspect, the present application provides a computer device, including: a memory, a processor, and a computer program stored on the memory and executable on the processor, where the processor executes the computer program to implement the steps of the rural distribution network decentralized energy storage system management and control method described in any one of the above.

[0032] In a fourth aspect, the present application provides a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the steps of the rural distribution network decentralized energy storage system management and control method described in any one of the above are implemented.

[0033] In a fifth aspect, the present application provides a computer program product, including a computer program, and when the computer program is executed by a processor, the steps of the rural distribution network decentralized energy storage system management and control method described in any one of the above are implemented.

[0034] According to the specific embodiments provided by the present application, the following technical effects are disclosed by the present application:

[0035] The present application provides a control method, device, equipment, medium and product for a decentralized energy storage system in rural power distribution networks. If the power value of the target rural power distribution substation within a certain time period in a day is greater than the set threshold, the target rural power distribution substation executes the substation autonomous mode within that time period; if the power value of the target rural power distribution substation within a certain time period in a day is not greater than the set threshold, the target rural power distribution substation executes the aggregated energy storage mode within that time period. When the power consumption of the rural power distribution substation is relatively high, heavy overload and low voltage may occur. At this time, the substation autonomous mode can be adopted to provide energy support for the substation, relieve heavy overload, improve low voltage and reduce the unbalance degree; while in other time periods, the power consumption of the substation is relatively low. At this time, the aggregated energy storage system mode is adopted to solve the problem of reverse power flow in the substation, meet the power supply guarantee in multiple scenarios. The present application can relieve heavy overload, improve low voltage, reduce the unbalance degree, meet the power supply guarantee in multiple scenarios and solve the problem of reverse power flow of photovoltaic power in rural power distribution substations. Description of the Drawings

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0037] Figure 1 It is an application environment diagram of a control method for a decentralized energy storage system in rural power distribution networks according to an embodiment of the present application;

[0038] Figure 2 It is a diagram of a decentralized energy storage technology solution of "aggregated energy storage system mode + substation autonomous mode" provided by an embodiment of the present application;

[0039] Figure 3 It is a flow chart of a control method for a decentralized energy storage system in rural power distribution networks provided by an embodiment of the present application;

[0040] Figure 4 It is a control architecture diagram of a decentralized energy storage provided by an embodiment of the present application;

[0041] Figure 5 It is a predicted daily load curve graph;

[0042] Figure 6 It is a graph of the operation result of the energy storage unit participating in the substation electrical load provided by an embodiment of the present application;

[0043] Figure 7 It is a structural diagram of a computer device provided by an embodiment of the present application. Detailed Embodiments

[0044] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Apparently, the described embodiments are only a part rather than all of the embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts shall fall within the protection scope of the present application.

[0045] To make the above objects, features, and advantages of the present application more obvious and understandable, the present application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0046] The control method for the rural and distribution network centralized energy storage system provided by the embodiments of the present application can be applied to an application environment as Figure 1 shown. Among them, the terminal 102 communicates with the server 104 through the network. The data storage system can store the data that the server 104 needs to process. The data storage system can be set separately, integrated on the server 104, placed on the cloud or other servers. The terminal 102 can send the typical daily load curve of the target rural power distribution area to the server 104. After receiving the typical daily load curve of the target rural power distribution area, for the typical daily load curve of the target rural power distribution area, the server 104 obtains the power values of each time period within a day of the target rural power distribution area according to the typical daily load curve of the target rural power distribution area; for any time period within a day of the target rural power distribution area, if the power value within the time period of the target rural power distribution area in a day is greater than the set threshold, the target rural power distribution area executes the substation autonomous mode within the time period; if the power value within the time period of the target rural power distribution area in a day is not greater than the set threshold, the target rural power distribution area executes the aggregated energy storage mode within the time period. The server 104 can feedback the obtained mode to the terminal 102. In addition, in some embodiments, the control method for the rural and distribution network centralized energy storage system can also be implemented by the server 104 or the terminal 102 alone. For example, the terminal 102 can directly perform the control of the rural and distribution network centralized energy storage system for the typical daily load curve of the target rural power distribution area, or the server 104 can obtain the typical daily load curve of the target rural power distribution area from the data storage system and perform the control of the rural and distribution network centralized energy storage system for the typical daily load curve of the target rural power distribution area.

[0047] Among them, the terminal 102 can be, but is not limited to, various desktop computers, laptop computers, smart phones, tablet computers, Internet of Things devices, and portable wearable devices. The Internet of Things devices can be smart speakers, smart TVs, smart air conditioners, smart in-vehicle devices, etc. The portable wearable devices can be smart watches, smart bracelets, head-mounted devices, etc. The server 104 can be implemented by an independent server or a server cluster composed of multiple servers, and can also be a cloud server.

[0048] In an exemplary embodiment, a control method for a distributed energy storage system in rural power distribution networks is provided. This method is executed by a computer device, which can be specifically executed by a computer device such as a terminal or a server alone, or jointly executed by a terminal and a server. The main idea of the control method for the distributed energy storage system in rural power distribution networks provided in this application is a distributed energy storage technology solution of "aggregated energy storage system mode + substation area autonomous mode", as Figure 2 and Figure 4 shown. The distributed energy storage technology solution is divided into an aggregated energy storage system mode and a substation area autonomous mode.

[0049] In the aggregated energy storage system mode, the decentralized energy storage units are connected to the energy storage control system of the grid dispatching terminal through the dispatching communication line. The control system of the aggregated energy storage system mode is respectively connected to the first energy storage unit energy management system of the first energy storage unit and the Nth energy storage sub-station energy management system of the Nth energy storage unit through the energy storage communication network. The total energy storage control system collects the current state of charge of the first energy storage unit and the Nth energy storage unit in real time, and generates corresponding execution instructions (charge and discharge according to the state of charge, SOC) based on the received power instruction of the grid dispatching terminal, the current state of charge (SOC) of the energy storage unit of the first energy storage unit and the Nth energy storage unit, and the current load power, and sends them to the first energy storage unit energy management system and the Nth energy storage unit energy management system respectively. The first energy storage unit energy management system and the Nth energy storage unit energy management system respectively control the first energy storage unit and the Nth energy storage unit to perform charge and discharge of corresponding power. During this process, the total energy storage control system monitors the charge and discharge power of each energy storage unit in real time and adjusts it to complete the power dispatching instruction of the grid dispatching. In the aggregated energy storage system mode, all controls and decisions are concentrated on a central node or control room. The central node or control room is responsible for collecting information from all units and making unified decisions. A hybrid mode is adopted, that is, while maintaining a certain degree of decentralized control, necessary coordination and optimization are carried out through the central node or control room. The decentralized energy storage units in the aggregated energy storage system mode can solve various problems in the power grid, mainly because of the following functions: The decentralized energy storage units can act as an energy buffer, store the excess electric energy in the power grid, and release it when needed, so as to balance the supply and demand relationship of the power grid; The energy storage unit can be quickly adjusted according to the real-time demand of the power grid, provide or absorb electric energy to cope with instantaneous load changes; Modern energy storage systems are usually equipped with advanced control strategies, which can intelligently perform charge and discharge operations according to the real-time data and prediction models of the power grid. In the autonomous mode of the distribution transformer area, the first energy storage unit and the Nth energy storage unit are respectively connected to the grid power line of the power grid through the power line of the first distribution transformer area of the first energy storage unit and the grid power line of the power grid through the Nth distribution transformer substation of the Nth energy storage unit power line. In the agricultural distribution transformer area, the uneven distribution of load in time and space leads to alternating light and heavy distribution. The autonomous mode of the distribution transformer area injects the energy storage unit nearby to achieve energy mutual assistance and realize power autonomy of the distribution transformer area. In the autonomous mode of the distribution transformer area, the control and decision-making of the system are distributed on each independent unit or node. Each unit can operate and make decisions independently without a centralized control center. In the embodiments of the present application, taking the method applied to Figure 1 server 104 in Figure 3 as an example for illustration, as

[0050] shown, it includes the following steps 201 to step 204. Among them:

[0051] Step 202: Obtain the power values of each time period within a day of the target rural power distribution substation according to the typical daily load curve of the target rural power distribution substation.

[0052] Step 203: For any time period within a day of the target rural power distribution substation, if the power value within the time period of the target rural power distribution substation within a day is greater than the set threshold, the target rural power distribution substation executes the substation autonomous mode within the time period. The substation autonomous mode is a well-known process in which the main meter of the substation monitors the substation load and cooperates with the control system to adjust the power consumption load.

[0053] Step 204: If the power value within the time period of the target rural power distribution substation within a day is not greater than the set threshold, the target rural power distribution substation executes the aggregated energy storage mode within the time period.

[0054] The aggregated energy storage mode is as follows:

[0055] If there is a state of charge less than the target value among the states of charge of all energy storage units in the target rural power distribution substation at the current moment, then control the main discharge unit at the current moment to operate in the constant voltage control mode, the intermediate group of energy storage units at the current moment and the main charging unit at the current moment to operate in the power control mode, and the intermediate group of energy storage units at the current moment and the main discharge unit at the current moment to discharge to the main charging unit and the load at the current moment; the main discharge unit is the energy storage unit with the largest state of charge among all energy storage units in the target rural power distribution substation; the main charging unit is the energy storage unit with the smallest state of charge among all energy storage units in the target rural power distribution substation; the intermediate group of energy storage units is all energy storage units in the target rural power distribution substation except the main discharge unit and the main charging unit; the constant voltage control mode means that the output voltage remains unchanged; the power control mode is to operate according to the power command. There are energy storage units with an initial SOC less than the target SOC in the system: In the initial stage of system startup, the energy storage units with a smaller SOC are in the charging state, and the corresponding energy storage converters operate in the charging mode, absorbing energy from other energy storage units. At the same time, all other energy storage units are in the discharging state, and the corresponding bidirectional energy storage converters operate in the discharging mode. On the premise of ensuring the normal operation of the system, it can not only ensure the reliable power supply of the load, but also provide energy for the energy storage units with a small amount of electricity. During this process, the main discharge unit always operates in the constant voltage control mode to ensure the normal operation of the system, and all other energy storage units operate in the power control mode (Constant voltage control mode: The main discharge unit operates in the constant voltage control mode, which means it will try to maintain a stable voltage level. This is usually to ensure the stable power supply of the system load and prevent voltage fluctuations from damaging sensitive equipment. In the constant voltage mode, the main discharge unit will automatically adjust its output according to the voltage feedback of the system to compensate for the voltage drop and keep the voltage constant. Power control mode: It means that these energy storage units adjust their output according to the power demand of the system. They do not directly control the voltage, but charge and discharge according to the real-time power demand. This mode allows the energy storage units to respond more flexibly to system requirements, such as providing additional power support during peak loads or storing excess energy during low loads).

[0056] If the states of charge of all energy storage units in the target rural power distribution substation at the current moment are greater than the target value, then control all energy storage units in the target rural power distribution substation at the current moment to discharge to the load, the main discharge unit at the current moment to operate in the constant voltage control mode, and the intermediate group of energy storage units at the current moment and the main charging unit at the current moment to operate in the power control mode. Since the initial SOC of each energy storage unit is greater than the target SOC, all devices always operate in the discharging mode during the balancing process, jointly providing energy for the load. The device with the largest SOC acts as a voltage stabilizer and operates in the constant voltage mode, and the other energy storage units can perform power control according to the calculated power command.

[0057] Adopt a control method that combines constant voltage control and power control. When the rated capacities of all devices are the same, sort the SOCs of the detected energy storage units according to their magnitudes. It is considered that the energy storage unit with the largest SOC value has the strongest voltage regulation ability. Therefore, select it as the main discharge unit to maintain the stability of the DC bus voltage, and it works in the constant voltage control mode, while other energy storage units work in the power control mode.

[0058] In practical applications, obtain the typical daily load curve of the target rural power distribution substation area, specifically including:

[0059] Based on the Monte Carlo simulation method, generate the 24-hour electrical load of the target rural power distribution substation area multiple times, and then extract the typical daily electrical load through the K-means clustering method to obtain the typical daily load curve.

[0060] In practical applications, obtaining the power values of each time period within a day of the target rural power distribution substation area according to the typical daily load curve of the target rural power distribution substation area specifically includes:

[0061] Perform multiple predictions on the typical daily load curve of the target rural power distribution substation area to obtain multiple prediction curves of the typical daily load curve of the target rural power distribution substation area.

[0062] Cluster the multiple prediction curves of the typical daily load curve of the target rural power distribution substation area to obtain the predicted daily load curve, and obtain the power values of each time period within a day of the target rural power distribution substation area according to the predicted daily load curve.

[0063] In practical applications, predicting the typical daily load curve of the target rural power distribution substation area to obtain the prediction curve of the typical daily load curve of the target rural power distribution substation area specifically includes:

[0064] According to the electrical load prediction error E r and the typical daily load curve, randomly generate prediction curves. The E r is different each time of prediction, so the prediction curves generated each time are also different.

[0065] The electrical load prediction error follows the standard normal distribution N(μ,σ 2 ), and the formula is:

[0066]

[0067] Select the prediction error E r according to formula (1), σ is the standard deviation of the electrical load prediction error, and μ represents the expectation of the electrical load prediction error.

[0068] The prediction curve can be calculated according to the following formula:

[0069] Τ l ′=(1 + E r ·er )·Τ l (2)

[0070] Wherein, T l and T l ' are the predicted load and the actual load at time l (obtained according to the typical daily load curve); e r is the maximum predicted load error, with a value of 0.05. The predicted curve is obtained based on the predicted load at all times.

[0071] In practical applications, due to the short - board effect, the maximum limit of the system working duration depends on the energy storage unit with the minimum SOC value. Therefore, it is designed to charge the main charging unit with the minimum SOC value at the maximum power of the converter. At the same time, it is necessary to calculate the magnitude of the power command that each device needs to send and receive until the system reaches the SOC equilibrium state and issue power commands to each energy storage unit, and it is stipulated that the discharge power of the main discharge unit does not exceed the maximum value allowed by the converter. Otherwise, measures should be taken to avoid irreversible damage to the converter.

[0072] Therefore, control the main charging unit at the current moment to work in the power control mode, specifically as follows:

[0073] When the load is light, if the main charging unit charges at the maximum power and the output power of the main discharge unit does not exceed the limit (that is, when the output power P on ≤ rated power P r and the output power of the main discharge unit does not exceed the limit, the system can not only meet the load demand but also enable the main charging unit to absorb energy at the maximum power, making full use of the energy storage converter. In this case, no power correction is required), then calculate T b according to formulas (3) to (4). At this time, the calculated T b is the time required for the SOC to reach the equilibrium state, and then calculate the power command of the main charging unit according to formula (5). Otherwise (that is, when P on >P r and the output power of the main discharge unit exceeds the limit, priority should be given to ensuring power supply to the load. In this case, it is allowed that the energy storage unit with the minimum SOC no longer absorbs energy at the rated power, and correct the power command it receives until the main discharge unit releases energy at the rated power, and ensure that the system reaches the SOC equilibrium state in the shortest time under trade - off), then correct the charging power P min(The main discharge unit undertakes the voltage stabilization function, and the magnitude of its output power depends on the deficit energy of the system. When the main charging unit charges at the maximum power, the main discharge unit is most likely to experience the phenomenon of over-limited discharge power, which will damage the converter. Therefore, it is necessary to perform power correction operations on the main charging unit to ensure that the power automatically output by the main discharge unit does not exceed the limit), and substitute the corrected charging power P min into formulas (3) to (4) to calculate T b Then, calculate the power command of the main charging unit according to formula (5), and continuously perform iterative calculations until the output power of the main discharge unit does not exceed the limit, that is, it can output at the maximum power, then the final charging power command can be determined, and finally the equilibrium time T that meets the constraint conditions can be obtained b , in this case, mutual charging and discharging can be achieved between devices. The specific steps for power correction of the main charging unit are as follows: According to the formula P c =P on -P r calculate the currently exceeded power P c , according to the formula P x =P c ·α calculate the power correction amount P x , according to P x and the charging power at the current moment to obtain the corrected charging power. α is an adjustment coefficient less than 1, which is used to determine the amount of power that needs to be reduced. By multiplying by an adjustment coefficient α less than 1, the output power can be gradually reduced instead of reducing the power to the rated value at one time. This progressive adjustment helps to avoid excessive impact on the system and ensure a smooth transition of the system.

[0074] When the load is a heavy load, multiple energy storage units are required to jointly provide energy for it. At this time, each device in the system is in a discharge state. The specified reference power command of the main charging unit is continuously corrected from a negative value to a positive value, and at the same time, it switches to a discharge state. Under the constraint that the output power of the main discharge unit does not exceed the limit, the satisfied T can be obtained by continuously iterating formulas (3) to (4) b .

[0075] Taking a system with N energy storage units as an example, first calculate the current electricity quantity E n of each energy storage unit and the total electricity quantity E sum of the system according to the battery parameters. Their expressions are respectively:

[0076]

[0077] In the above formula, E is the rated capacity of the energy storage unit, and SOC n is the SOC of the nth energy storage unit at the current moment.

[0078] When the output power of the main discharge unit does not exceed the limit, by calculating the difference in the amount of electricity between the initial charge of the main charging unit and the state when the system reaches the SOC balance state, the time T required to reach the balance state can be solved. b , which is:

[0079]

[0080] In the above formula, P min is the charging power of the main charging unit, N represents the total number of energy storage units in the target rural power distribution area, and E min represents the electricity of the energy storage unit with the least current electricity in the target rural power distribution area; P load is the load power at the current moment.

[0081] Since the rated capacity of each energy storage unit in the system is the same, the power distribution can still be calculated using the above idea. The energy E n stored in real time by each energy storage unit and T b are known, then the reference value for absorbing or emitting power can be determined based on the difference between the electricity of each device and the average energy of the system at the balance state. Therefore, the intermediate group of energy storage units at the current moment is controlled to work in the power control mode, specifically:

[0082] Calculate the electricity of each energy storage unit in the target rural power distribution area at the current moment based on the state of charge of each energy storage unit in the target rural power distribution area at the current moment.

[0083] Calculate the time required for the target rural power distribution area to reach the balance state based on the electricity of each energy storage unit in the target rural power distribution area at the current moment, the charging power of the main charging unit at the current moment, and the load power of the target rural power distribution area at the current moment.

[0084] Calculate the power commands of each energy storage unit in the intermediate group of energy storage units based on the electricity of each energy storage unit in the target rural power distribution area at the current moment, the load power of the target rural power distribution area at the current moment, and the time required for the target rural power distribution area to reach the balance state.

[0085] Preferably, calculate the electricity of each energy storage unit in the target rural power distribution area at the current moment based on the state of charge of each energy storage unit in the target rural power distribution area at the current moment; calculate the time required for the target rural power distribution area to reach the balance state based on the electricity of each energy storage unit in the target rural power distribution area at the current moment, the charging power of the main charging unit at the current moment, and the load power of the target rural power distribution area at the current moment, specifically calculated using formula (3) and formula (4).

[0086] Preferably, the power commands of the energy storage units in the intermediate group are calculated based on the current power of each energy storage unit in the target rural power distribution substation area, the load power of the target rural power distribution substation area at the current moment, and the time required for the target rural power distribution substation area to reach the equilibrium state, specifically including:

[0087] According to the formula Calculate the power command of the nth energy storage unit in the intermediate group of energy storage units, where P n Represents the power command of the nth energy storage unit in the intermediate group of energy storage units, E n Represents the current power of the nth energy storage unit in the target rural power distribution substation area, E ave Represents the average power of the target rural power distribution substation area at the equilibrium moment, T b Represents the time required for the target rural power distribution substation area to reach the equilibrium state, calculated according to formula (4).

[0088] Since the main discharge unit plays a role in stabilizing the voltage, the reference value of the output power is to automatically output the energy shortage of the system on the premise of ensuring the stability of the DC bus voltage. Before the SOC reaches equilibrium, the maximum value of the power reference command of the main discharge unit is the rated power P r When the SOC reaches the equilibrium state, the power reference value of the main discharge unit is the power required to evenly distribute the load. Since the main discharge unit does not have the power control function, the calculated power command does not take effect at any time and is only used to check whether the output power of the main discharge unit exceeds the limit. If the following formula is satisfied, it means that the output power of the main discharge unit does not exceed the limit.

[0089] -P load -P min +P mid <P max (6)

[0090]

[0091] P max Is the rated output power of the main discharge unit.

[0092] Once the output power of the main discharge unit exceeds the limit, that is, the system satisfies:

[0093] -P load -P min +P mid >P max (8)

[0094] Then it is impossible to continue maintaining the stability of the DC bus voltage, and the system enters an abnormal operating state, unable to provide reliable electrical energy for the load. At this time, the equalization time obtained from the above analysis and calculation is no longer valid. It is necessary to attenuate the energy absorbed by the main charging unit, and it is designed to attenuate at a rate of 100W / s until it meets the condition that the output power of the main discharging unit does not exceed the limit. Only then can the final charging power command be determined, that is, the main discharging unit operates in the constant voltage control mode, and the output power of the main discharging unit is obtained in real time. When the output power exceeds the limit, the energy absorbed by the main charging unit is attenuated until the output power of the main discharging unit does not exceed the limit, and then the attenuation of the energy absorbed by the main charging unit is stopped.

[0095] For each energy storage unit, they all have their own rated charge / discharge power. For the energy storage unit in the charging state, the input power has been specified, that is, the received power command does not exceed the maximum power of the converter.

[0096] The distributed energy storage system adopts the DC-side multi-branch parallel technology. Based on the traditional centralized scheme, the battery clusters are isolated by adding DC / DC converters at the outlet of the battery clusters. After the DC / DC converters are aggregated, they are connected to the DC side of the centralized PCS. 2 to 4 PCSs are connected in parallel to a local transformer and then connected to the grid after stepping up by the transformer. By adding DC / DC DC isolation in the system, it can effectively avoid DC arcing, circulating current, and capacity loss caused by DC parallel connection, significantly improve the safety of the system, and thus improve the system efficiency. Based on this, the control method of the distributed energy storage system for rural distribution networks provided by this application can give full play to the spatio-temporal advantages of electrochemical energy storage by constructing a flexible distributed energy storage operation scheme of "aggregated energy storage system mode + substation area autonomous mode" with a matrix structure and easy loading and unloading. Taking the distributed energy storage units as the linkage carriers for the substation areas and the substation area central controller as the coordination main body, it promotes the autonomous balance of flexible resources in rural distribution substation areas for active demand response. In the aggregated energy storage system mode of the distributed energy storage, peak shaving and frequency modulation are realized in the 10kV voltage level area of the distribution network; in the substation area autonomous mode, through the coordinated control of the substation area central controller, the distributed energy storage units match the power regulation of flexible resources in the substation area in a time-sharing and area-based manner, and solve prominent problems such as reverse power transmission of photovoltaic power in the substation area, alleviating heavy overload, improving low voltage, reducing unbalance degree, and meeting power supply guarantee in multiple scenarios with high cost performance, flexibility and efficiency.

[0097] This application uses the daily load curve to judge when the total energy storage system controls the single distributed energy storage unit and when the single distributed energy storage unit intervenes in the rural distribution substation area to achieve substation area autonomy. Figure 5 For predicting the daily load curve. From Figure 5It can be seen that when it is from 10:00 to 13:00 and from 16:00 to 21:00, the power used by the rural distribution transformer area is relatively high, and heavy overload and low voltage may occur. At this time, the autonomous mode of the transformer area can be adopted to provide energy support for the transformer area, relieve heavy overload and improve low voltage. During other time periods, the power consumption rate of the transformer area is relatively low. At this time, the aggregated energy storage system mode is adopted to solve the problem of reverse power flow in the transformer area. Figure 6 It is a graph of the operation result of the energy storage unit participating in the electrical load of the transformer area. From Figure 6 It can be seen that through the reasonable allocation of the energy storage unit, the load power of the transformer area is significantly relieved.

[0098] 1. Through the reasonable adjustment and control of the decentralized energy storage units in the decentralized energy storage, this application can effectively avoid the problems of long-term redundancy and high cost of the fixed energy storage in the current transformer area, realize the reasonable mobilization of the resources in the transformer area, and amortize and reduce the energy storage cost.

[0099] 2. This application adopts a control mode combining the "aggregated energy storage system mode + autonomous mode of the transformer area", dynamically adjusts the charge and discharge of the energy storage unit, reactive power adjustment, etc., so as to effectively solve the problems of reverse power flow of photovoltaic power in the transformer area, relieve heavy overload, improve low voltage, reduce the unbalance degree, meet the power supply guarantee in multiple scenarios, etc.

[0100] 3. This application can improve the reliability of the power grid: The decentralized energy storage system helps to relieve the power supply pressure of the rural power grid, especially during peak hours or when the output of renewable energy is unstable. The system can act as a buffer to improve the reliability and response ability of the power grid.

[0101] 4. This application adopts an intelligent allocation of the charge and discharge process of the energy storage unit to ensure the utilization of electric energy at the best time, and at the same time responds to the immediate adjustment requirements of the power grid, increasing the flexibility and stability of the system operation.

[0102] 5. The decentralized energy storage system of this application can meet various electric energy demands of the rural distribution transformer area. Using standard energy cabinet products, a modular, easy-to-load, unload and move decentralized energy storage technology solution is constructed.

[0103] 6. This application can effectively solve the prominent problems such as reverse power flow of photovoltaic power in the rural distribution transformer area, relieve heavy overload, improve low voltage, reduce the unbalance degree, meet the power supply guarantee in multiple scenarios, etc., and promote the large-scale application of green energy.

[0104] 7. This application can not only improve the energy utilization efficiency and economy of the existing rural power grid, but also improve the stability and reliability of the power grid. At the same time, it promotes the integration of renewable energy, providing an effective technical means for the modernization and intelligentization of the rural power grid.

[0105] The present application also provides an application scenario, which applies the above-mentioned control method for the rural and distribution network centralized energy storage system. Specifically: The control method for the rural and distribution network centralized energy storage system provided in this embodiment can be applied to multiple application scenarios such as power supply guarantee for substations, power supply guarantee for important meetings, power supply guarantee in disaster preparedness situations, power supply guarantee for emergency repairs, power supply guarantee for planned maintenance, and heavy overload in substations.

[0106] Based on the same inventive concept, the embodiment of the present application also provides a control device for the rural and distribution network centralized energy storage system for implementing the above-mentioned control method for the rural and distribution network centralized energy storage system. The solution provided by this device for solving problems is similar to the solution described in the above method. Therefore, the specific limitations in one or more embodiments of the control device for the rural and distribution network centralized energy storage system provided below can refer to the limitations on the control method for the rural and distribution network centralized energy storage system in the above text, and will not be repeated here.

[0107] In an exemplary embodiment, a control device for the rural and distribution network centralized energy storage system is provided, including:

[0108] An acquisition module, configured to acquire the typical daily load curve of the target rural power distribution substation.

[0109] A power calculation module, configured to obtain the power values of each time period within a day of the target rural power distribution substation according to the typical daily load curve of the target rural power distribution substation.

[0110] A substation autonomous mode execution module, configured to, for any time period within a day of the target rural power distribution substation, if the power value within the time period of the target rural power distribution substation within a day is greater than a set threshold, the target rural power distribution substation executes the substation autonomous mode within the time period.

[0111] An aggregated energy storage mode execution module, configured to, if the power value within the time period of the target rural power distribution substation within a day is not greater than a set threshold, the target rural power distribution substation executes the aggregated energy storage mode within the time period.

[0112] The aggregated energy storage mode is:

[0113] If there is a state of charge less than the target value among the states of charge of all energy storage units in the target rural power distribution substation at the current moment, then control the main discharge unit at the current moment to operate in the constant voltage control mode, the intermediate group of energy storage units at the current moment and the main charging unit at the current moment to operate in the power control mode, and the intermediate group of energy storage units at the current moment and the main discharge unit at the current moment to discharge to the main charging unit and the load at the current moment; the main discharge unit is the energy storage unit with the largest state of charge among all energy storage units in the target rural power distribution substation; the main charging unit is the energy storage unit with the smallest state of charge among all energy storage units in the target rural power distribution substation; the intermediate group of energy storage units is all energy storage units in the target rural power distribution substation except the main discharge unit and the main charging unit; the constant voltage control mode means that the output voltage remains unchanged; the power control mode is to operate according to the power command.

[0114] If the states of charge of all energy storage units in the target rural power distribution substation at the current moment are all greater than the target value, then control all energy storage units in the target rural power distribution substation at the current moment to discharge to the load, the main discharge unit at the current moment to operate in the constant voltage control mode, and the intermediate group of energy storage units at the current moment and the main charging unit at the current moment to operate in the power control mode.

[0115] In an exemplary embodiment, a computer device is provided. The computer device can be a server or a terminal, and its internal structure diagram can be as Figure 7 shown. The computer device includes a processor, a memory, an input / output interface (Input / Output, abbreviated as I / O), and a communication interface. Among them, the processor, the memory, and the input / output interface are connected through a system bus, and the communication interface is connected to the system bus through the input / output interface. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program, and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the computer device is used to store the control data of the distributed energy storage system for rural power distribution networks. The input / output interface of the computer device is used to exchange information between the processor and external devices. The communication interface of the computer device is used to communicate with external terminals through a network connection. When the computer program is executed by the processor, it implements a method for controlling a distributed energy storage system for rural power distribution networks.

[0116] Those skilled in the art can understand, Figure 7The structure shown is only a block diagram of some structures related to the solution of this application, and does not constitute a limitation on the computer device to which the solution of this application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine some components, or have different component arrangements. In an exemplary embodiment, a computer device is provided, including a memory and a processor. A computer program is stored in the memory, and when the processor executes the computer program, the steps in the above method embodiments are implemented.

[0117] In an exemplary embodiment, a computer-readable storage medium is provided, storing a computer program, and when the computer program is executed by a processor, the steps in the above method embodiments are implemented.

[0118] In an exemplary embodiment, a computer program product is provided, including a computer program, and when the computer program is executed by a processor, the steps in the above method embodiments are implemented.

[0119] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use, and processing of relevant data need to comply with relevant regulations.

[0120] Those of ordinary skill in the art can understand that all or part of the processes in the methods of the above embodiments can be completed by instructing relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above methods. Among them, any reference to a memory, database, or other medium used in the embodiments provided in the present application can include at least one of non-volatile and volatile memories. Non-volatile memories can include read-only memory (ROM), magnetic tapes, floppy disks, flash memories, optical memories, high-density embedded non-volatile memories, resistive random access memories (ReRAM), magnetoresistive random access memories (MRAM), ferroelectric random access memories (FRAM), phase change memories (PCM), graphene memories, etc. Volatile memories can include random access memory (RAM) or external cache memories, etc. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc.

[0121] The databases involved in the embodiments provided in the present application can include at least one of relational databases and non-relational databases. Non-relational databases can include distributed databases based on blockchain, etc., without limitation. The processors involved in the embodiments provided in the present application can be general-purpose processors, central processors, graphics processors, digital signal processors, programmable logics, data processing logics based on quantum computing, etc., without limitation.

[0122] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0123] Specific examples are used in this article to elaborate on the principles and implementation manners of the present application. The descriptions of the above embodiments are only used to help understand the method and its core idea of the present application; at the same time, for those of ordinary skill in the art, according to the idea of the present application, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation to the present application.

Claims

1. A control method for a distributed energy storage system in rural power distribution networks, characterized in that The energy storage system control method includes: Obtaining the typical daily load curve of the target rural power distribution substation area; Obtaining the power values of each time period within a day of the target rural power distribution substation area according to the typical daily load curve of the target rural power distribution substation area; For any time period within a day of the target rural power distribution substation area, if the power value within the time period of the target rural power distribution substation area within a day is greater than the set threshold, the target rural power distribution substation area executes the substation area autonomous mode within the time period; If the power value within the time period of the target rural power distribution substation area within a day is not greater than the set threshold, the target rural power distribution substation area executes the aggregated energy storage mode within the time period; The aggregated energy storage mode is: If there is a state of charge less than the target value among the states of charge of all energy storage units of the target rural power distribution substation area at the current moment, control the main discharge unit at the current moment to work in the constant voltage control mode, the intermediate group energy storage units at the current moment and the main charging unit at the current moment to work in the power control mode, and the intermediate group energy storage units at the current moment and the main discharge unit at the current moment discharge to the main charging unit and the load at the current moment; the main discharge unit is the energy storage unit with the largest state of charge among all energy storage units of the target rural power distribution substation area; the main charging unit is the energy storage unit with the smallest state of charge among all energy storage units of the target rural power distribution substation area; the intermediate group energy storage units are all energy storage units of the target rural power distribution substation area except the main discharge unit and the main charging unit; the constant voltage control mode means that the output voltage remains unchanged; the power control mode is to operate according to the power command; If the states of charge of all energy storage units of the target rural power distribution substation area at the current moment are all greater than the target value, control all energy storage units of the target rural power distribution substation area at the current moment to discharge to the load, the main discharge unit at the current moment to work in the constant voltage control mode, and the intermediate group energy storage units at the current moment and the main charging unit at the current moment to work in the power control mode; Controlling the intermediate group energy storage units at the current moment to work in the power control mode specifically includes: Calculating the electricity quantity of each energy storage unit of the target rural power distribution substation area at the current moment based on the state of charge of each energy storage unit of the target rural power distribution substation area at the current moment; Calculate the time required for the target rural power distribution substation area to reach the equilibrium state based on the current power of each energy storage unit in the target rural power distribution substation area, the current charging power of the main charging unit, and the current load power of the target rural power distribution substation area; specifically: According to the formula Calculate the time required for the target rural power distribution substation area to reach the equilibrium state, where T b Is the time required for the target rural power distribution substation area to reach the equilibrium state, E n Represents the current power of the nth energy storage unit in the target rural power distribution substation area, N represents the total number of energy storage units in the target rural power distribution substation area, E min Represents the power of the energy storage unit with the least current power in the target rural power distribution substation area, P min Represents the current charging power of the main charging unit, P load Represents the current load power of the target rural power distribution substation area; Calculating the power command of each energy storage unit in the intermediate group energy storage units based on the electricity quantity of each energy storage unit of the target rural power distribution substation area at the current moment, the load power of the target rural power distribution substation area at the current moment, and the time required for the target rural power distribution substation area to reach the balanced state.

2. The control method of the distributed energy storage system for rural power distribution network according to claim 1, wherein The obtaining the power values of each time period within a day of the target rural power distribution substation area according to the typical daily load curve of the target rural power distribution substation area specifically includes: performing multiple predictions on the typical daily load curve of the target rural power distribution substation area to obtain multiple prediction curves of the typical daily load curve of the target rural power distribution substation area; Performing clustering on the multiple prediction curves of the typical daily load curve of the target rural power distribution substation area to obtain the power values of each time period within a day of the target rural power distribution substation area.

3. The control method of the distributed energy storage system for rural power distribution network according to claim 1, wherein Calculate the power commands of each energy storage unit in the intermediate group based on the current power of each energy storage unit in the target rural power distribution substation area, the current load power of the target rural power distribution substation area, and the time required for the target rural power distribution substation area to reach the equilibrium state. Specifically, it includes: According to the formula Calculate the power command of the nth energy storage unit in the intermediate group, where P n represents the power command of the nth energy storage unit in the intermediate group, P load represents the current load power of the target rural power distribution substation area, E n represents the current power of the nth energy storage unit in the target rural power distribution substation area, T b represents the time required for the target rural power distribution substation area to reach the equilibrium state, and N represents the total number of energy storage units in the target rural power distribution substation area.

4. A control device for a distributed energy storage system in rural power distribution networks, characterized in that The rural distribution network decentralized energy storage system control device includes: an obtaining module for obtaining the typical daily load curve of the target rural power distribution substation area; A power calculation module for obtaining the power values of each time period within a day of the target rural power distribution substation area according to the typical daily load curve of the target rural power distribution substation area; The substation autonomous mode execution module is used to, for any time period within a day of the target rural power distribution substation, if the power value of the target rural power distribution substation within the time period of a day is greater than the set threshold, then the target rural power distribution substation executes the substation autonomous mode within the time period; The aggregated energy storage mode execution module is used to, if the power value of the target rural power distribution substation within the time period of a day is not greater than the set threshold, then the target rural power distribution substation executes the aggregated energy storage mode within the time period; The aggregated energy storage mode is as follows: If there is a state of charge less than the target value among the states of charge of all energy storage units of the target rural power distribution substation at the current moment, then control the main discharge unit at the current moment to work in the constant voltage control mode, the intermediate group of energy storage units at the current moment and the main charging unit at the current moment to work in the power control mode, and the intermediate group of energy storage units at the current moment and the main discharge unit at the current moment discharge to the main charging unit and the load at the current moment; the main discharge unit is the energy storage unit with the largest state of charge among all energy storage units of the target rural power distribution substation; the main charging unit is the energy storage unit with the smallest state of charge among all energy storage units of the target rural power distribution substation; the intermediate group of energy storage units is all energy storage units of the target rural power distribution substation except the main discharge unit and the main charging unit; the constant voltage control mode means that the output voltage remains unchanged; the power control mode is to operate according to the power command; If the states of charge of all energy storage units of the target rural power distribution substation at the current moment are all greater than the target value, then control all energy storage units of the target rural power distribution substation at the current moment to discharge to the load, the main discharge unit at the current moment to work in the constant voltage control mode, and the intermediate group of energy storage units at the current moment and the main charging unit at the current moment to work in the power control mode; Controlling the intermediate group of energy storage units at the current moment to work in the power control mode specifically includes: Calculating the electricity quantity of each energy storage unit of the target rural power distribution substation at the current moment based on the states of charge of each energy storage unit of the target rural power distribution substation at the current moment; Calculate the time required for the target rural power distribution substation to reach the equilibrium state based on the current power of each energy storage unit in the target rural power distribution substation, the current charging power of the main charging unit, and the current load power of the target rural power distribution substation; specifically: According to the formula Calculate the time required for the target rural power distribution substation to reach the equilibrium state, where T b Is the time required for the target rural power distribution substation to reach the equilibrium state, E n Represents the current power of the nth energy storage unit in the target rural power distribution substation, N represents the total number of energy storage units in the target rural power distribution substation, E min Represents the power of the energy storage unit with the least power at the current moment in the target rural power distribution substation, P min Represents the current charging power of the main charging unit, P load Represents the current load power of the target rural power distribution substation; Calculating the power command of each energy storage unit in the intermediate group of energy storage units based on the electricity quantity of each energy storage unit of the target rural power distribution substation at the current moment, the load power of the target rural power distribution substation at the current moment, and the time required for the target rural power distribution substation to reach the equilibrium state.

5. A computer device, comprising: A memory, a processor, and a computer program stored on the memory and executable on the processor, wherein the processor executes the computer program to implement the control method for the rural power distribution network decentralized energy storage system according to any one of claims 1-3.

6. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the control method for the rural power distribution network decentralized energy storage system according to any one of claims 1-3.

7. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by the processor, it implements the control method for the rural power distribution network decentralized energy storage system according to any one of claims 1-3.

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