Design method and device for comprehensive energy system of transformer substation
By designing a microgrid system in a substation, combining distributed power supply and energy storage devices, and switching operation modes with grid-connected switches, the problem of high power consumption in traditional substations is solved, and efficient utilization of clean energy and reduction of power consumption is achieved.
Patent Information
- Application Number
- CN202411327360.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-23
- Publication Date
- 2024-12-27
AI Technical Summary
In traditional substations, the power consumption of loads in the station is obtained through the step-down transformer through the step-down transformer in the station, greatly increasing the power consumption of the power grid.
Design a comprehensive energy system for substations, and determine the grid connection mode by planning the microgrid for stations, including distributed power supplies, energy storage devices, control systems and substation-related load power systems. , and optimize power utilization by switching operation modes using grid-connected power supply, independent power supply, and traditional power supply modes.
It effectively reduces the power consumption rate of substations, reduces grid power consumption, and improves energy utilization efficiency.
Smart Images
Figure CN119209511A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of energy system design, and relates to a method and a device for designing a comprehensive energy system for a transformer substation. Background Art
[0002] As the world further improves its goals for energy efficiency and carbon emissions, renewable energy such as wind and solar energy have been developed and utilized in large quantities, and the grid energy structure is gradually moving towards clean and efficient. On the other hand, as a key hub connecting different power grids, green and efficient substation electrical primary design solutions have become an important part of the transformation and upgrading of the grid energy structure.
[0003] However, the load electricity in traditional substations is still drawn through the low-voltage busbar of the station or the transmission lines of other substations through step-down transformers, which greatly increases the power consumption of the power grid. Summary of the invention
[0004] The present invention provides a method and device for designing a comprehensive energy system for a substation, which overcomes the shortcomings of the above-mentioned prior art and can effectively solve the problem that in the design of existing traditional substations, the load electricity in the substation is still drawn through the low-voltage bus of the station or other substation transmission lines through a step-down transformer, which greatly increases the power consumption of the power grid.
[0005] One of the technical solutions of the present invention is achieved by the following measures: A method for designing a comprehensive energy system for a substation, comprising: Plan the composition of the station microgrid, which includes distributed power sources, energy storage devices, control systems and substation-related load power systems; Establish a station-use microgrid access method, and use the grid-connected switch to connect the distributed power source, energy storage device, control system and substation-related load power system to the DC microgrid; Determine the grid-connected mode of the station microgrid, where the grid-connected mode includes a DC microgrid connection mode and an AC microgrid connection mode; Control the status of each grid-connected switch to switch the station microgrid operation mode.
[0006] The following are further optimizations and / or improvements to the above technical solutions: The above-mentioned distributed power sources include wind power generation and photovoltaic power generation. The photovoltaic modules of photovoltaic power generation are arranged on the roof of the substation with a larger area. The wind power generation uses small wind turbines of 10kW or less and is arranged on the roof of a smaller area.
[0007] The above-mentioned substation-related load power systems include the power supply for the cooling system of the transformer in the station, the power supply for the opening and closing of switches and circuit breakers, the power supply for the secondary system in the station, and the power supply for other power facilities in the station and its auxiliary systems.
[0008] The above energy storage device must meet the following conditions: Ccell≥(Psource-Pload)*Tmax; Pcell ≥ Psource; Among them, Ccell is the maximum capacity of the energy storage device, Pcell is the maximum charging power of the energy storage device, Psource is the maximum power generation of renewable energy, including the sum of the maximum power generation of wind power generation and photovoltaic power generation, Pload is the daily station AC and DC load power, and Tmax is the maximum power generation duration of new energy.
[0009] The above-mentioned operation modes include grid-connected power supply mode, independent power supply mode, and traditional power supply mode; Grid-connected power supply mode: The station microgrid is connected to the grid for power supply operation, and the power supply system in the microgrid and the station transformer jointly supply power to the load in the station; Independent power supply mode: The station microgrid is independently powered and operated, and the microgrid independently supplies power to the internal loads of the microgrid, and uses energy storage units to maintain the stable operation of the microgrid; Traditional power supply mode: Exit the grid-connected power supply mode, and the microgrid uses the traditional power supply method to supply power to the internal loads of the microgrid.
[0010] The second technical solution of the present invention is achieved by the following measures: a substation integrated energy system design device, comprising: Composition planning unit, planning the composition of station microgrid, where the station microgrid includes distributed power supply, energy storage device, control system and substation related load power system; The access establishment unit is used to establish a station microgrid access mode, and the distributed power source, energy storage device, control system and substation-related load power system are connected to the DC microgrid using a grid-connected switch; A grid connection mode determination unit, which determines a station microgrid grid connection mode, wherein the grid connection mode includes a DC microgrid connection mode and an AC microgrid connection mode; The operation mode is switched to control the status of each grid-connected switch to switch the station microgrid operation mode.
[0011] The present invention plans a microgrid system consisting of a distributed power supply combined with wind and solar power, an energy storage device, a control system and a substation-related load power consumption system. The microgrid system is connected to the station power low-voltage bus through a grid-connected switch, and then the station microgrid grid-connected mode is determined. Finally, the grid-connected power supply mode, independent power supply mode and traditional power supply mode are flexibly switched through the grid-connected switch. In this way, clean energy power generation technologies such as wind power generation and photovoltaic power generation are used to supply power to the power load in the station, reduce the station power consumption rate, and solve the technical problem of using a wind, solar and storage microgrid system to reduce the energy consumption of the substation power system. BRIEF DESCRIPTION OF THE DRAWINGS
[0012] Attached Figure 1 is a flow chart of the method of the present invention; Attached Figure 2 It is a schematic diagram of electrical wiring corresponding to the method of the present invention; Attached Figure 3 A schematic diagram of a microgrid access grid connection method of the present invention; Attached Figure 4 A schematic diagram of a microgrid grid-connected mode of the present invention; Attached Figure 5 This is a flow chart of the operation mode switching of the present invention; Attached Figure 6 The AC and DC load and busbar configuration diagram of the entire substation according to Embodiment 2 of the present invention; Attached Figure 7 It is a schematic diagram of the device structure of the present invention. DETAILED DESCRIPTION
[0013] The present invention is not limited by the following embodiments, and specific implementation methods can be determined based on the technical solution of the present invention and actual conditions.
[0014] The present invention will be further described below in conjunction with embodiments and drawings: Embodiment 1: As attached Figure 1 , 2 As shown, an embodiment of the present invention discloses a method for designing a comprehensive energy system for a substation, comprising: Step 101, planning the composition of a station microgrid, wherein the station microgrid includes a distributed power source, an energy storage device, a control system, and a power system for loads related to the substation, and the distributed power source adopts a combination of wind power generation and photovoltaic power generation; The above steps are as follows: Distributed power sources use a combination of wind power generation and photovoltaic power generation; photovoltaic modules for photovoltaic power generation are arranged on the larger rooftop of the substation, and wind power generation uses small wind turbines of 10kW or less that are arranged on the smaller rooftop. Wind energy and solar energy complement each other day and night, season by season, and space by space.
[0015] The substation-related load power consumption system includes the power supply and auxiliary systems responsible for the cooling system power consumption of the transformer in the station, the power consumption of switches and knife switches, the power consumption of the secondary system in the station, and the power supply for other power facilities in the station (lighting, air conditioning, data center).
[0016] The energy storage device should be combined with the technical conditions of the substation, according to the statistics of AC and DC regular loads and typical wind power and photovoltaic output, and reasonably calculate the configuration power and capacity, and should meet the following conditions: Ccell≥(Psource-Pload)*Tmax; Pcell ≥ Psource; In the formula, Ccell is the maximum capacity of the energy storage device, Pcell is the maximum charging power of the energy storage device, Psource is the maximum power generation of renewable energy, including the sum of the maximum power generation of wind power generation and photovoltaic power generation, Pload is the daily station AC and DC load power, and Tmax is the maximum power generation duration of new energy.
[0017] Step 102, establish a station microgrid access mode, and use AC grid-connected switches to connect the distributed power source, energy storage device, control system and substation-related load power system to the DC microgrid.
[0018] The above-mentioned grid-connected switch has the ability to cut off load current and fault current, and can cooperate with the control system to switch the operation mode, that is, cooperate to complete step 104. Further, when a fault occurs in the power grid, the grid-connected switch actively realizes the decoupling operation of the microgrid and the grid side, keeps the microgrid in isolated grid operation, and can cooperate with the microgrid to reverse power to realize the black start of the substation when the whole station loses power.
[0019] Specifically, the above-mentioned station microgrid can be connected to the power grid in the following manner: Figure 3 .
[0020] Step 103, determining a station-use microgrid grid connection mode, wherein the grid connection mode includes a DC microgrid connection mode and an AC microgrid connection mode; In this embodiment, the station microgrid grid-connected mode can adopt a DC microgrid wiring method, that is, the DC load is directly powered by the DC bus, and the AC load is connected to the DC bus through an inverter device, and the DC bus is connected to the station power AC bus through DC / AC conversion.
[0021] For details, please refer to the attached Figure 4 , attached Figure 4 The medium DC microgrid system includes a DC bus, a grid-side converter, a DC part of the energy storage system and a DC part of the wind and solar system; the DC bus voltage level is 220V, and the DC microgrid system is connected to the 380V station power AC bus through a grid-side DC / AC converter; the DC part of the wind and solar system includes a photovoltaic power generation DC part and a wind power generation DC part. The photovoltaic power generation DC part uses photovoltaic modules in series to merge through a combiner box and is connected to the DC bus through a DC / DC converter. The wind power generation DC part is an AC wind turbine connected to the DC bus through AC / DC; the DC part of the energy storage system uses a DC / DC converter to access the DC bus, and the DC / DC converter has a bidirectional power flow function.
[0022] Step 104, determining the operation mode of the station microgrid, wherein the operation modes include a grid-connected power supply mode, an independent power supply mode, and a traditional power supply mode.
[0023] As attached Figure 5 As shown, the details are as follows: Grid-connected power supply mode: In this mode, the Figure 2 , close the grid-connected switch K, the wind-solar-storage microgrid system is connected to the grid for power supply operation, and the power supply system and station transformer in the microgrid jointly supply power to the load in the station.
[0024] Independent power supply mode: In this mode, the Figure 2 , disconnect the grid-connected switch K from the grid side, the microgrid is powered independently, independently supplies power to the internal loads of the microgrid, and uses the energy storage unit to maintain the stable operation of the microgrid. When the conditions are met, the grid-connected switch K can be closed and switched to the grid-connected power supply mode.
[0025] Traditional power supply mode: In this mode, the Figure 2 In the grid-connected power supply mode, the connection switches K1, K2, and K3 between the wind-solar-storage system and the DC bus are cut off. At the same time, the microgrid load is switched to the station power low-voltage bus for power supply. Therefore, when the wind-solar-storage system exits the standby state, you can try to close the connection switches K1, K2, and K3 to enter the grid-connected power supply mode.
[0026] The present invention plans a microgrid system consisting of a distributed power supply combined with wind and solar power, an energy storage device, a control system and a substation-related load power consumption system. The microgrid system is connected to the station power low-voltage bus through a grid-connected switch, and then the station microgrid grid-connected mode is determined. Finally, the grid-connected power supply mode, independent power supply mode and traditional power supply mode are flexibly switched through the grid-connected switch. In this way, clean energy power generation technologies such as wind power generation and photovoltaic power generation are used to supply power to the power load in the station, reduce the station power consumption rate, and solve the technical problem of using a wind, solar and storage microgrid system to reduce the energy consumption of the substation power system.
[0027] Example 2: This example applies the substation integrated energy system design method disclosed in the present invention to the substation engineering construction / renovation scenario, analyzes the adaptability of the present invention to different scenarios, and verifies the effectiveness of the present invention.
[0028] Taking multiple substation construction / renovation scenarios as examples, the main parameters of the scenarios are shown in Table 1: Table 1 Main parameters of four scenarios .
[0029] Attached Figure 6 The diagram is a diagram of the AC and DC loads and busbar configuration of the entire substation designed using the substation comprehensive energy system design method disclosed in the present invention.
[0030] Scenario A: The daily peak power generation of renewable energy is far less than the energy consumed by common loads, and no energy storage device is required. When wind and solar power are fully generated during the day and there is no photovoltaic power generation at night, all renewable energy power generation can be absorbed by the station load in real time, achieving full generation and utilization, without the problem of wind and solar power abandonment.
[0031] Scenario B: The daily peak power generation of renewable energy is greater than the daily common load of the substation, and the energy storage configuration is 500kW / 1600kWh (power / capacity). When there is no photovoltaic power generation at night, the power generation of renewable energy can be absorbed by the station load, but during the daytime when renewable energy is generated, it is necessary to reasonably configure and dispatch the energy storage system to effectively store most of the surplus energy of renewable energy and adjust the load curve.
[0032] Scenario C: The daily peak power generation of renewable energy is greater than the daily common load of the substation, and the energy storage configuration is 250kW / 600kWh (power / capacity). When there is no photovoltaic power generation at night, the power generation of renewable energy can be absorbed by the station load, but during the daytime when renewable energy is generated, it is necessary to reasonably configure and dispatch the energy storage system to effectively store most of the surplus energy of renewable energy and realize the function of adjusting the load curve.
[0033] Scenario D: The daily peak power generation of renewable energy is greater than the daily common load of the substation, and the energy storage configuration is 200kW / 400kWh (power / capacity). When there is no photovoltaic power generation at night, the power generation of renewable energy can be absorbed by the station load, but during the daytime when renewable energy is generated, it is necessary to reasonably configure and dispatch the energy storage system to effectively store most of the surplus energy of renewable energy, and to adjust the load curve through reverse transmission.
[0034] Under normal circumstances, energy storage can fully store the surplus energy when new energy is generated. However, when the performance of the energy storage battery deteriorates or the energy storage scheduling fails, the energy generated by new energy may exceed the energy that can be absorbed by the station's power load. In this case, the wind turbine and a group of photovoltaic modules can be removed first. If the power generation and consumption balance cannot be met, the two groups of photovoltaic modules are combined into a pair and removed in pairs until the power generation and consumption balance is met to maintain the stability of the system in the station.
[0035] The adaptability analysis of the above four scenarios shows that the substation microgrid system using renewable distributed power generation technology has the ability of flexible scheduling under the microgrid grid structure and has excellent adaptability to different scenarios. So in summary, the substation integrated energy system design method can reduce the station power consumption rate and solve the problem of reducing the power consumption of the substation power system by using the wind, solar and storage microgrid system.
[0036] Embodiment 3: As attached Figure 7As shown, the embodiment of the present invention discloses a device for designing a comprehensive energy system for a substation, comprising: Composition planning unit, planning the composition of station microgrid, where the station microgrid includes distributed power supply, energy storage device, control system and substation related load power system; The access establishment unit is used to establish a station microgrid access mode, and the distributed power source, energy storage device, control system and substation-related load power system are connected to the DC microgrid using a grid-connected switch; A grid connection mode determination unit, which determines a station microgrid grid connection mode, wherein the grid connection mode includes a DC microgrid connection mode and an AC microgrid connection mode; The operation mode switching unit controls the status of each grid-connected switch to switch the station microgrid operation mode.
[0037] The above technical features constitute several embodiments of the present invention, which have strong adaptability and corresponding implementation effects. Non-essential technical features can be added or reduced according to actual needs to meet the requirements of different situations.
Claims
1. A method for designing a comprehensive energy system for a substation, characterized in that: include: Plan the composition of the station microgrid, which includes distributed power sources, energy storage devices, control systems and substation-related load power systems; Establish a station-use microgrid access method, and use the grid-connected switch to connect the distributed power source, energy storage device, control system and substation-related load power system to the DC microgrid; Determine the grid-connected mode of the station microgrid, where the grid-connected mode includes a DC microgrid connection mode and an AC microgrid connection mode; Control the status of each grid-connected switch to switch the station microgrid operation mode.
2. The method for designing a comprehensive energy system for a substation according to claim 1, characterized in that: The distributed power sources include wind power generation and photovoltaic power generation. The photovoltaic modules of photovoltaic power generation are arranged on the roof of the substation with a larger area. The wind power generation uses small wind turbines of 10kW or less and is arranged on the roof of a smaller area.
3. The method for designing a comprehensive energy system for a substation according to claim 1 or 2, characterized in that: The substation-related load power consumption system includes the power supply and its auxiliary systems responsible for the cooling system power consumption of the transformer in the station, the power consumption of switches and knife switches for opening and closing, the power consumption of the secondary system in the station, and the power supply for other power facilities in the station.
4. The method for designing a comprehensive energy system for a substation according to claim 1 or 2, characterized in that: The energy storage device must meet the following conditions: Ccell≥(Psource-Pload)*Tmax; Pcell ≥ Psource; Among them, Ccell is the maximum capacity of the energy storage device, Pcell is the maximum charging power of the energy storage device, Psource is the maximum power generation of renewable energy, including the sum of the maximum power generation of wind power generation and photovoltaic power generation, Pload is the daily station AC and DC load power, and Tmax is the maximum power generation duration of new energy.
5. The method for designing a comprehensive energy system for a substation according to claim 3, characterized in that: The energy storage device must meet the following conditions: Ccell≥(Psource-Pload)*Tmax; Pcell ≥ Psource; Among them, Ccell is the maximum capacity of the energy storage device, Pcell is the maximum charging power of the energy storage device, Psource is the maximum power generation of renewable energy, including the sum of the maximum power generation of wind power generation and photovoltaic power generation, Pload is the daily station AC and DC load power, and Tmax is the maximum power generation duration of new energy.
6. The method for designing a comprehensive energy system for a substation according to claim 1, 2 or 5, characterized in that: The operation modes include grid-connected power supply mode, independent power supply mode, and traditional power supply mode; Grid-connected power supply mode: The station microgrid is connected to the grid for power supply operation, and the power supply system in the microgrid and the station transformer jointly supply power to the load in the station; Independent power supply mode: The station microgrid is independently powered and operated, and the microgrid independently supplies power to the internal loads of the microgrid, and uses energy storage units to maintain the stable operation of the microgrid; Traditional power supply mode: Exit the grid-connected power supply mode, and the microgrid uses the traditional power supply method to supply power to the internal loads of the microgrid.
7. A device for designing a substation integrated energy system using the method according to any one of claims 1 to 6, characterized in that: include: Composition planning unit, planning the composition of station microgrid, where the station microgrid includes distributed power supply, energy storage device, control system and substation related load power system; The access establishment unit is used to establish a station microgrid access mode, and the distributed power source, energy storage device, control system and substation-related load power system are connected to the DC microgrid using a grid-connected switch; A grid connection mode determination unit, which determines a station microgrid grid connection mode, wherein the grid connection mode includes a DC microgrid connection mode and an AC microgrid connection mode; The operation mode is switched to control the status of each grid-connected switch to switch the station microgrid operation mode.