A substation flexible bridge energy storage device and control method
By introducing a flexible bridge energy storage device into the power distribution system, the energy transfer and optimization between two independent power sources can be realized, solving the problem of inflexible energy allocation, improving energy absorption rate and system efficiency, and achieving low-carbon and high-efficiency operation.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHINA RAILWAY FIRST SURVEY & DESIGN INST GRP
- Filing Date
- 2026-02-06
- Publication Date
- 2026-06-19
AI Technical Summary
In high-energy-consuming entities such as rail transit, large industrial parks, and mining enterprises, the existing power distribution system suffers from inflexible energy allocation and low intelligence, resulting in low energy absorption rate and resource waste. In particular, after the integration of distributed photovoltaic power, the system structure and power flow distribution are difficult to optimize.
By introducing a flexible bridge energy storage device, through two sets of converters, two matching transformers and a shared energy storage battery compartment, the energy can be rationally transferred and optimally configured between two independent power sources. By utilizing the charging and discharging characteristics of the energy storage battery compartment and the current conversion characteristics of power electronic devices, combined with time-of-use electricity price arbitrage, the energy can be optimally dispatched.
It improves the absorption rate of renewable energy, optimizes the power flow distribution of the system, reduces operating losses, enhances the flexibility of energy allocation, avoids resource waste, and supports the low-carbon and efficient operation of the system.
Smart Images
Figure CN122246814A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of power distribution technology, specifically relating to a flexible bridge energy storage device and control method for a substation. Background Technology
[0002] Rail transit, large industrial parks, and mining enterprises, as high-energy-consuming entities, urgently need to construct integrated power generation, grid, load, and storage systems to achieve low-carbon and efficient operation. In these energy-consuming scenarios, power distribution substations often draw two or more power sources from the public grid. Constrained by factors such as investment scale and the current state of the grid, the power supply capacity varies, and the level of intelligence is low, resulting in insufficient flexibility in energy allocation and difficulty in effectively implementing power flow control. The integration of distributed photovoltaic systems on idle resources such as rooftops and vacant land further alters the original system structure and power flow distribution. Coupled with the independent operation of two power sources, this not only makes precise matching of source and load difficult and results in low renewable energy absorption rates, but also restricts the efficiency of power supply and distribution due to the lack of mutual support between independent power sources. It can even lead to investment waste and resource idleness when enterprises expand production. Summary of the Invention
[0003] To overcome the shortcomings of existing technologies, this invention provides a flexible bridge energy storage device and control method for substations. By collecting multi-dimensional parameters of source-grid-load-storage in real time, it realizes the rational migration and optimized configuration of energy between two independent power sources, achieving the control objectives of low system loss and high penetration rate of new energy.
[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A flexible bridge energy storage device for substations, characterized in that: The flexible bridge energy storage device is introduced into existing power distribution substations; The flexible bridge energy storage device includes two sets of converters, two matching transformers, and a shared energy storage battery compartment. The DC bus of the shared energy storage battery compartment is connected to the DC side of two sets of converters, and the AC side of the two sets of converters is connected to two matching transformers respectively. The two matching transformers are connected to two sections of the bus of the 10kV substation respectively.
[0005] Furthermore, for cases where the energy storage and migration capacity is less than 0.5MW and the difference between the energy storage capacity and the migration capacity is less than 0.5MW, a single-level power device DC non-grouping system is adopted, which shares an energy storage battery compartment including multiple energy storage units for energy storage and energy transfer. For situations where the energy storage and migration capacity is greater than 0.5MW and the difference between the energy storage capacity and the migration capacity is less than 0.5MW, a two-stage power device DC non-grouping system is adopted, with a shared energy storage battery compartment including multiple energy storage units. Each energy storage unit is equipped with a DC / DC converter between itself and the DC bus. The energy storage unit is used for energy storage and energy transfer. For situations where both the energy storage capacity and the migration capacity exceed 0.5MW, and the energy storage capacity is greater than the migration capacity by 0.5MW, a two-stage power device DC grouping system is adopted, sharing an energy storage battery compartment including an energy migration unit and an energy storage unit; each energy migration unit and energy storage unit is equipped with a DC / DC converter between itself and the DC bus; the energy migration unit is used for the storage and release of a portion of the migrated energy; the energy storage unit is used to absorb the off-peak electricity and unconsumed renewable energy from the nearby connecting section bus.
[0006] Furthermore, along the direction of energy transfer, the energy is transferred and optimized between the two independent busbars of the substation by sequentially passing through a matching transformer for step-down, a converter for three-phase rectification, a DC bus, a converter for three-phase inversion, and a matching transformer for step-up.
[0007] A control method for a flexible bridge energy storage device in a substation, comprising the following specific steps: Step 1: Collect voltage and current data of the two power supply input sides of the two bus sections and the new energy power generation system, calculate the load power transmitted by the two power supplies and the power generation of the new energy; collect the state of charge value of the energy storage battery compartment to determine the charging and discharging conditions. Step 2: Based on the load power transmitted by the two bus incoming power supplies and the working capacity of the two power supplies, calculate the load rate of the two power supplies and determine whether energy needs to be transferred between the two independent bus sections. Step 3: Based on the load power transmitted by the two bus incoming power sources and the power generated by new energy sources, combined with the time-of-use electricity price meter and the charge status of the energy storage battery compartment, determine whether the energy storage battery compartment is charging or discharging; that is, through the charging and discharging of the energy storage battery compartment, further realize peak-valley electricity price arbitrage and improve the new energy consumption rate.
[0008] Furthermore, during periods of grid parity or peak electricity prices, if the total load capacity is greater than the total generation capacity, but the load capacity of bus I is less than the generation capacity and the battery discharge capacity is less than the set threshold, the flexible bridge energy storage device is activated to make bridge 1 rectify and bridge 2 invert, with the rectification and inversion power being the same. The flexible bridge energy storage device is in energy migration mode, transferring the surplus photovoltaic power of bus I to bus II.
[0009] Furthermore, during periods of grid parity or peak electricity prices, if the total load capacity is greater than the total generation capacity, and the load capacity of bus section I is less than the generation capacity and the battery discharge capacity is greater than the set threshold, the flexible bridge energy storage device is activated to make bridge 1 rectify and bridge 2 invert, and the rectification power is less than the inverting power, the difference being the battery discharge power. The flexible bridge energy storage device operates in the energy migration + discharge state.
[0010] The beneficial effects of this invention are: 1) This invention enables the rational transfer and optimized configuration of energy between two independent power sources, which can effectively optimize the power flow distribution of the system, reduce operating losses, and improve the renewable energy consumption rate; 2) This invention breaks the barrier of independent operation between the two power sources in traditional substations, enhances the flexibility of energy allocation, helps improve the overall efficiency of power supply and distribution systems, avoids resource waste, and provides practical technical support for the low-carbon and efficient upgrading of existing power generation, grid, load and storage systems. Attached Figure Description
[0011] Figure 1 This is the control logic diagram for a flexible bridge energy storage device. Figure 2 This is a schematic diagram of a flexible bridge energy storage device (DC ungrouped primary power unit); Figure 3 This is a schematic diagram of a flexible bridge energy storage device (two-stage power devices with DC ungrouped power); Figure 4 A schematic diagram of a flexible bridge energy storage device (two-stage power device DC grouping) system; Figure 5 The graph shows the photovoltaic power generation, load power consumption, and time-of-use electricity price curves for a certain power distribution station on a certain workday. Figure 6 This is a schematic diagram of the revenue-maximizing operation curve for a certain power distribution station. Detailed Implementation
[0012] The present invention will now be described in detail with reference to specific embodiments.
[0013] This invention provides a flexible bridge energy storage device and control method for substations. By utilizing the energy storage charging and discharging characteristics and the power electronic device conversion characteristics, and by real-time acquisition of multi-dimensional parameters of source-grid-load-storage, it realizes the rational migration and optimized configuration of energy between two independent power sources, achieving the control objectives of low system loss and high penetration rate of new energy.
[0014] A flexible bridge energy storage device is introduced into an existing power distribution substation. The flexible bridge energy storage device includes two sets of converters, two matching transformers, and a shared energy storage battery compartment. The DC bus of the shared energy storage battery compartment is connected to the DC side of the two sets of converters, and the AC side of the two sets of converters is connected to the two matching transformers. The two matching transformers are connected to two bus sections of the 10kV substation: bus section I and bus section II. The energy storage battery compartment stores and releases off-peak electricity or unconsumed renewable energy, enabling peak-valley electricity price arbitrage and improving the renewable energy consumption rate.
[0015] The energy transfer process of the flexible bridge energy storage device in the substation is as follows: along the direction of energy transfer, the energy is transferred sequentially through the matching transformer step-down, the converter three-phase rectification, the DC bus, the converter three-phase inversion, and the matching transformer step-up, so as to realize the reasonable transfer and optimized configuration of energy between the two independent bus sections of the substation; the same applies in the opposite direction.
[0016] For situations where the energy storage and migration capacity is small (less than 0.5MW) and the difference between the energy storage capacity and the migration capacity is small (less than 0.5MW), a single-level power device DC non-grouping system is adopted, sharing an energy storage battery compartment containing multiple energy storage units for energy storage and energy transfer, such as... Figure 2 As shown, this system has fewer energy storage components in the energy storage battery compartment, making its control simple and energy consumption low.
[0017] For situations where the energy storage and migration capacity is large (greater than 0.5MW) and the difference between the energy storage capacity and the migration capacity is small (less than 0.5MW), a two-stage power device DC non-grouping system is adopted. The shared energy storage battery compartment includes multiple energy storage units, each with a DC / DC converter connected to the DC bus. The energy storage units are used for energy storage and energy transfer. This system has a larger number of energy storage components in the battery compartment, allowing for better control of the battery compartment and resulting in greater stability of the DC bus. Figure 3 As shown.
[0018] For situations where both energy storage and migration capacities are large (exceeding 0.5MW), and the energy storage capacity is significantly larger than the migration capacity (exceeding 0.5MW), a two-stage power device DC grouping system is adopted. The shared energy storage battery compartment includes two main functional units: an energy migration unit and an energy storage unit. Each energy migration unit and energy storage unit is equipped with a DC / DC converter connected to the DC bus. The energy migration unit is primarily used for the storage and release of a portion of the migrated energy; the energy storage unit is used to absorb off-peak electricity from the connecting bus and unused renewable energy sources, such as... Figure 4 As shown, this system has a large number of energy storage components in the energy storage battery compartment, and the energy storage capacity is significantly greater than the migration capacity, which can better realize energy storage, utilization and migration, making the system operate more efficiently.
[0019] like Figure 1 As shown, the present invention also provides a control method for a flexible bridge energy storage device in a substation, the specific steps of which are as follows: Step 1: Collect voltage and current data of the two power supply input sides of the two bus sections and the new energy power generation system, calculate the load power transmitted by the two power supplies and the power generation of the new energy; collect the state of charge value of the energy storage battery compartment to determine the charging and discharging conditions. Step 2: Based on the load power transmitted by the two bus incoming power supplies and the working capacity of the two power supplies, calculate the load rate of the two power supplies and determine whether energy needs to be transferred between the two independent bus sections; that is, if the load rate of one power supply is overloaded, energy is transferred from the non-overloaded bus to the overloaded bus to achieve energy balance between the two power supplies. Step 3: Based on the load power transmitted by the two bus incoming power sources and the power generated by new energy sources, combined with the time-of-use electricity price meter and the charge status of the energy storage battery compartment, determine whether the energy storage battery compartment is charging or discharging; that is, through the charging and discharging of the energy storage battery compartment, further realize peak-valley electricity price arbitrage and improve the new energy consumption rate.
[0020] During periods of grid parity or peak electricity prices, if the total load capacity is greater than the total generation capacity, but the load capacity of bus I is less than the generation capacity and the battery discharge capacity is less than the set threshold, the flexible bridge energy storage device is activated to make bridge 1 rectify and bridge 2 invert, with the rectification and inversion power being the same. The flexible bridge energy storage device is in energy migration mode, transferring the surplus photovoltaic power of bus I to bus II.
[0021] During periods of grid parity or peak electricity prices, if the total load capacity is greater than the total generation capacity, and the load capacity of bus section I is less than the generation capacity and the battery discharge capacity is greater than the set threshold, the flexible bridge energy storage device is activated to make bridge 1 rectify and bridge 2 invert, and the rectification power is less than the inverting power, the difference being the battery discharge power. The flexible bridge energy storage device operates in the energy migration + discharge state.
[0022] Taking a certain substation as an example for analysis, the details are as follows: Figure 5 The figure shows the photovoltaic power generation, load power consumption, and time-of-use electricity price curves for a certain substation on a certain workday of a month. From 1:00 to 5:30, the electricity price is in the off-peak period, and the substation's load operates during a low-power period, requiring the substation to utilize grid power. From 12:00 to 13:45, the electricity price is also in the off-peak period, and the substation's load operates during a high-power period, utilizing both grid power and photovoltaic power generation. From 17:00 to 22:45, the electricity price is in the peak period, and the substation's load power shows a trend of first rising and then falling, with the load utilizing grid power and, at some times, photovoltaic power generation. The photovoltaic power generation and load power consumption curves show that from 9:30 to 16:30, photovoltaic power generation exceeds load power consumption.
[0023] By utilizing energy storage devices during off-peak hours and periods of surplus photovoltaic power, energy is released to the load during peak electricity price periods. The energy transfer function of the flexible bridge balances the energy demand of the two busbars, maximizing the profitability of the power generation, grid, load, and energy storage system. An ideal operating state is as follows: Figure 6As shown in the figure, positive values for the energy storage battery compartment power indicate stored electrical energy, while negative values indicate the supply of electrical energy to the load. Therefore, by utilizing a photovoltaic power generation system and the energy storage and transfer functions of a flexible bridge energy storage device, the distribution station receives electrical energy from the grid during off-peak and partial grid parity periods, and supplies power to the load through photovoltaic and energy storage batteries during peak and extra-peak periods. This improves the utilization rate of renewable energy in the distribution station, reduces operating costs, and achieves the goal of maximizing revenue control.
[0024] The content of this invention is not limited to the embodiments listed. Any equivalent modifications made by those skilled in the art to the technical solutions of this invention by reading this specification are covered by the claims of this invention.
Claims
1. A flexible bridge energy storage device for a substation, characterized in that: The flexible bridge energy storage device is introduced into existing power distribution substations; The flexible bridge energy storage device includes two sets of converters, two matching transformers, and a shared energy storage battery compartment. The DC bus of the shared energy storage battery compartment is connected to the DC side of two sets of converters, and the AC side of the two sets of converters is connected to two matching transformers respectively. The two matching transformers are connected to two sections of the bus of the 10kV substation respectively.
2. The flexible bridge energy storage device for a substation according to claim 1, characterized in that: For situations where the energy storage and migration capacity is less than 0.5MW and the difference between the energy storage capacity and the migration capacity is less than 0.5MW, a single-level power device DC non-grouping system is adopted, which shares an energy storage battery compartment including multiple energy storage units for energy storage and energy transfer. For situations where the energy storage and migration capacity is greater than 0.5MW and the difference between the energy storage capacity and the migration capacity is less than 0.5MW, a two-stage power device DC non-grouping system is adopted, with a shared energy storage battery compartment including multiple energy storage units. Each energy storage unit is equipped with a DC / DC converter between itself and the DC bus. The energy storage unit is used for energy storage and energy transfer. For situations where both the energy storage capacity and the migration capacity exceed 0.5MW, and the energy storage capacity is greater than the migration capacity by 0.5MW, a two-stage power device DC grouping system is adopted, sharing an energy storage battery compartment including an energy migration unit and an energy storage unit; each energy migration unit and energy storage unit is equipped with a DC / DC converter between itself and the DC bus; the energy migration unit is used for the storage and release of a portion of the migrated energy; the energy storage unit is used to absorb the off-peak electricity and unconsumed renewable energy from the nearby connecting section bus.
3. The flexible bridge energy storage device for a substation according to claim 1, characterized in that: The energy transfer process is as follows: along the direction of energy transfer, the energy is transferred sequentially through the matching transformer step-down, the converter three-phase rectification, the DC bus, the converter three-phase inversion, and the matching transformer step-up, so as to realize the reasonable transfer and optimized configuration of energy between the two independent bus sections of the substation.
4. A control method for a flexible bridge energy storage device in a substation, characterized in that: The specific steps are as follows: Step 1: Collect voltage and current data of the two power supply input sides of the two bus sections and the new energy power generation system, calculate the load power transmitted by the two power supplies and the power generation of the new energy; collect the state of charge value of the energy storage battery compartment to determine the charging and discharging conditions. Step 2: Based on the load power transmitted by the two bus incoming power supplies and the working capacity of the two power supplies, calculate the load rate of the two power supplies and determine whether energy needs to be transferred between the two independent bus sections. Step 3: Based on the load power transmitted by the two bus incoming power sources and the power generated by new energy sources, combined with the time-of-use electricity price meter and the charge status of the energy storage battery compartment, determine whether the energy storage battery compartment is charging or discharging; that is, through the charging and discharging of the energy storage battery compartment, further realize peak-valley electricity price arbitrage and improve the new energy consumption rate.
5. The control method for a flexible bridge energy storage device in a substation according to claim 4, characterized in that: During periods of grid parity or peak electricity prices, if the total load capacity is greater than the total generation capacity, but the load capacity of bus I is less than the generation capacity and the battery discharge capacity is less than the set threshold, the flexible bridge energy storage device is activated to make bridge 1 rectify and bridge 2 invert, with the rectification and inversion power being the same. The flexible bridge energy storage device is in energy migration mode, transferring the surplus photovoltaic power of bus I to bus II.
6. The control method for a flexible bridge energy storage device in a substation according to claim 4, characterized in that: During periods of grid parity or peak electricity prices, if the total load capacity is greater than the total generation capacity, and the load capacity of bus section I is less than the generation capacity and the battery discharge capacity is greater than the set threshold, the flexible bridge energy storage device is activated to make bridge 1 rectify and bridge 2 invert, and the rectification power is less than the inverting power, the difference being the battery discharge power. The flexible bridge energy storage device operates in the energy migration + discharge state.