A grid and heat network coordinated photovoltaic power station abandoned electricity utilization system

Abstract

The utility model discloses a kind of photovoltaic power station abandoned electricity utilization systems of power grid and heat grid cooperation, including photovoltaic module, inverter and station transformer, for converting light energy into electric energy and conveying to power grid;The electric heating cooperation heat supplement unit includes bidirectional controller, first electric heater, second electric heater, heat storage equipment, water supply pump, backwater pump, first temperature sensing module and second temperature sensing module;The bidirectional controller is used to control the power distribution of first electric heater, second electric heater and the start-stop of water supply pump, backwater pump according to the medium temperature of heat storage equipment and city heat grid water supply temperature;Through the implementation of the application, heat storage heat supplement is carried out using the dispatching abandoned electricity of photovoltaic power station, improves photovoltaic power generation utilization rate, relieves power grid peak shaving pressure, simultaneously heat supplement is carried out to city pipe network, reduces heating cost, improves the toughness of city in electric heating double network aspect.

Description

Technical Field

[0001] This utility model relates to the field of curtailment power utilization technology, and in particular to a photovoltaic power plant curtailment power utilization system that coordinates the power grid and heating network. Background Technology

[0002] The installed capacity of centralized photovoltaic power plants in my country has increased rapidly, but this has also brought about corresponding problems:

[0003] The high curtailment rate of photovoltaic power plants is due to limitations in local grid integration and power grid construction. The Northwest region is rich in solar resources, but its grid integration rate is significantly lower than that of coastal areas, resulting in a high curtailment rate for photovoltaic power plants.

[0004] The construction of photovoltaic power plants is restricted. Due to the high rate of solar power curtailment, the construction of photovoltaic power plants is severely limited in regions with abundant solar resources, such as the Northwest and Northeast, which have excellent natural conditions.

[0005] On the other hand, many urban heating networks have been in use for a long time, with outdated equipment and significant heat loss, resulting in heating at the end of the network failing to meet technical specifications. The conventional approach is to add supplementary heating stations in the middle sections of the network, using gas-fired boilers or electrode boilers for supplementary heating, which increases heating costs.

[0006] In summary, a photovoltaic power plant curtailment utilization system that coordinates the power grid and heating network is needed to address the shortcomings of existing technologies. Utility Model Content

[0007] To address the shortcomings of existing technologies, this invention provides a photovoltaic power plant curtailment utilization system that coordinates power grid and heating network, aiming to solve the aforementioned problems.

[0008] This application provides a photovoltaic power plant curtailment utilization system that coordinates power grid and heating network for connecting to urban heating network, including a centralized photovoltaic power plant power generation unit and an electric-thermal co-heating unit;

[0009] The centralized photovoltaic power station power generation unit includes photovoltaic modules, inverters, and station transformers, which are used to convert light energy into electrical energy and transmit it to the power grid;

[0010] The electrothermal co-heating unit includes a bidirectional controller, a first electric heater, a second electric heater, a heat storage device, a water supply pump, a return water pump, a first temperature sensing module, and a second temperature sensing module.

[0011] The bidirectional controller is used to control the power distribution of the first electric heater and the second electric heater, as well as the start and stop of the water supply pump and the return water pump, according to the medium temperature of the thermal storage device and the water supply temperature of the urban heating network. The first electric heater is used to convert electrical energy into heat energy and store it in the thermal storage device. The second electric heater is used to directly heat the water supply network of the urban heating network. The thermal storage device is connected to the water supply pump and the water supply network of the urban heating network. The thermal storage device is also connected to the return water pump and the return water network of the urban heating network. The first temperature sensing module is used to monitor the water temperature of the water supply network of the urban heating network, and the second temperature sensing module is used to monitor the water temperature of the return water network of the urban heating network.

[0012] The bidirectional controller is also connected to the first temperature sensing module and the second temperature sensing module via signal connection.

[0013] Furthermore, the heat storage device is a solid heat storage device or a molten salt heat storage device, and the heat storage device includes a high-temperature zone and a medium-low temperature zone.

[0014] Furthermore, the high-temperature zone of the heat storage device is used to perform the first heat replenishment on the water supply of the urban heating network, raising its temperature to a first preset temperature; the medium-low temperature zone of the heat storage device is used to perform the second heat replenishment on the return water of the urban heating network, preheating its temperature to a second preset temperature.

[0015] Furthermore, the first preset temperature is 120℃-130℃, and the second preset temperature is 80℃.

[0016] Furthermore, when the medium temperature of the heat storage device is lower than the preset requirement value, the bidirectional controller controls the first electric heater to directly provide emergency heat replenishment to the pipeline medium flowing through the heat replenishment circuit.

[0017] Furthermore, both the first and second electric heaters are connected to the urban heating network to form an emergency direct compensation circuit.

[0018] Furthermore, it also includes a backup heating component, which is used to connect to the heating circuit for auxiliary heating.

[0019] Furthermore, the backup heating assembly includes an air source heat pump and an electrode boiler, wherein the air source heat pump and / or electrode boiler are used to connect to the heating circuit.

[0020] Technical effects of this utility model:

[0021] 1. In this utility model, by constructing a dual-grid electric and thermal supplementary heating unit inside a large-scale centralized photovoltaic power station, the power station's dispatched waste electricity is used for heat storage and supplementary heating, thereby improving the utilization rate of photovoltaic power generation, alleviating the pressure on the power grid's peak regulation, and simultaneously supplementing the urban pipeline network, reducing heating costs, and improving the city's resilience in terms of electric and thermal dual-grid systems.

[0022] 2. In this utility model, the abandoned power is directly connected to the electric heater through the DC side, avoiding inverter and transformer losses and improving energy conversion efficiency; and the heat storage equipment is used to perform staged heat supplementation for supply water and return water, which increases the temperature of supply water and preheats return water at the same time, thereby reducing the energy consumption of heating companies.

[0023] 3. In this utility model, the thermal storage status and heating network demand are monitored in real time through a two-way controller, realizing the dynamic allocation and optimized scheduling of electrical and thermal energy; it has emergency direct compensation and backup heat compensation mechanisms, which can respond quickly when thermal storage is insufficient or the heat load suddenly increases, ensuring stable heating supply, effectively utilizing clean energy, reducing fossil energy consumption, and meeting the needs of low-carbon city development. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the overall system principle of this utility model.

[0026] Figure 2 This is a schematic diagram of the power grid and heat network coupling system of this utility model.

[0027] In the diagram: 100-Centralized photovoltaic power station power generation unit, 101-Photovoltaic module, 102-Inverter, 103-Station transformer; 200-Electric-thermal co-heating unit, 201-Bidirectional controller, 202-First electric heater, 203-Second electric heater, 204-Heat storage equipment, 204a-High temperature zone, 204b-Medium and low temperature zone, 205-Water supply pump, 206-Return water pump, 207-First temperature sensing module, 208-Second temperature sensing module; 300-Urban heating network; 400-Backup heat supplement component, 401-Air source heat pump, 402-Electrode boiler. Detailed Implementation

[0028] To facilitate understanding of this utility model, a more detailed description is provided below with reference to the accompanying drawings and specific embodiments. It should be noted that when an element is described as "fixed to" another element, it can be directly on the other element, or one or more intermediate elements may exist between them. When an element is described as "connected to" another element, it can be directly connected to the other element, or one or more intermediate elements may exist between them. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this specification are for illustrative purposes only.

[0029] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the scope of the invention. The term "and / or" as used in this specification includes any and all combinations of one or more of the associated listed items.

[0030] Example 1:

[0031] Reference Figure 1 As shown, a photovoltaic power station curtailment utilization system that coordinates power grid and heating network is used to connect to urban heating network 300. It includes a centralized photovoltaic power station power generation unit 100 and an electric-thermal co-heating supplementary heating unit 200. The electric-thermal co-heating supplementary heating unit 200 is used for grid-heat network co-heating supplementary heating.

[0032] The centralized photovoltaic power station power generation unit 100 includes photovoltaic modules 101, inverters 102 and station transformers 103. The photovoltaic modules 101 convert light energy into direct current. Part of the direct current is converted into alternating current that meets the grid requirements by the inverters 102 and the station transformers 103 and then connected to the grid. The other part of the "wasted power" that cannot be connected to the grid is guided to the electric and thermal co-heating unit 200.

[0033] The electrothermal synergistic heating unit 200 includes:

[0034] The bidirectional controller 201, which adopts a PLC or industrial computer and has built-in control logic, is used to control the power distribution of the first electric heater 202 and the second electric heater 203, as well as the start and stop of the water supply pump 205 and the return water pump 206, according to the medium temperature of the heat storage device 204 and the water supply temperature of the urban heating network 300.

[0035] The first electric heater 202 is used to convert electrical energy into heat energy and store it in the heat storage device 204;

[0036] The second electric heater 203 is used to directly heat the water supply network of the urban heating network 300;

[0037] The heat storage device 204 is connected to the water supply pump 205 and the water supply network of the urban heating network 300. The heat storage device 204 is also connected to the return water pump 206 and the return water network of the urban heating network 300. In this embodiment, a solid heat storage device filled with magnesium bricks is used. The heating element of the electric heater 201 is embedded in the heat storage body to convert electrical energy into heat energy and store it.

[0038] Both the water supply pump 205 and the return water pump 206 are variable frequency pumps, controlled by the bidirectional controller 201;

[0039] The first temperature sensing module 207 is used to monitor the water temperature of the urban heating network 300.

[0040] The second temperature sensing module 208 is used to monitor the return water temperature of the urban heating network 300;

[0041] The bidirectional controller 201 is also connected to the first temperature sensing module 207 and the second temperature sensing module 208 via signals;

[0042] The heat output terminal of the first electric heater 202 is connected to the heat storage device 204 to convert electrical energy into heat energy and store it in the heat storage device 204;

[0043] The heat storage device 204 is connected to the water supply pipe of the urban heating network 300 via a pipeline and a water supply pump 205. The heat storage device 204 is also connected to the return water pipe of the urban heating network 300 via a pipeline and a return water pump 206, together forming a heat replenishment circuit.

[0044] The bidirectional controller 201 monitors the power grid dispatch instructions (to determine whether power curtailment has occurred) and the water supply temperature sensor signals of the urban heating network 300 in real time. When power curtailment occurs and the heating network water supply temperature is lower than the set value, the controller performs the following operations:

[0045] Close the DC side switch to guide the abandoned power to the first electric heater 202 and start heating and storing energy in the thermal storage device 204;

[0046] Start the water supply pump 205 and the return water pump 206 to introduce a portion of the water supply with a lower temperature in the urban heating network into the heat storage device 204 for heating;

[0047] Based on the temperature sensor readings inside the heat storage device 204, the power of the first electric heater 202 is dynamically adjusted to prioritize heat storage.

[0048] The heated water is pumped back into the water supply pipes of the city's heating network 300 to achieve supplemental heating.

[0049] This embodiment realizes the direct and efficient conversion of abandoned photovoltaic power into thermal energy, which is then stably replenished to the urban heating network through a thermal storage device, thereby improving energy utilization efficiency.

[0050] Example 2:

[0051] This embodiment is basically the same as Embodiment 1, except that it provides a system with graded heat storage and heat replenishment. Based on Embodiment 1, this embodiment optimizes the heat storage device 204 and the heat replenishment strategy to achieve tiered utilization of energy.

[0052] In this embodiment, the heat storage device 204 is a vertical molten salt heat storage device. Utilizing the temperature stratification characteristics of molten salt at different heights, a high-temperature region 204a (located in the upper part of the device, with temperatures reaching over 400°C) and a medium-low temperature region 204b (located in the lower middle part of the device, with temperatures approximately 150-250°C) are naturally formed. The device contains two independent sets of heat exchanger piping: one set located in the high-temperature region and the other in the medium-low temperature region.

[0053] The bidirectional controller 201 employs a more refined control strategy:

[0054] First supplementary heating (main water supply heating): The controller first pumps the lower-temperature water supply (e.g., 50°C) from the city heating network 300 into the heat exchanger pipeline located in the high-temperature zone 204a, and uses high-temperature molten salt to heat it to the first preset temperature (e.g., 120°C-130°C). This is high-temperature supplementary heating.

[0055] Secondary heat replenishment (return water preheating): The return water with a lower temperature (e.g., 40°C) that has been returned after heat exchange by the user is pumped into the heat exchanger pipeline located in the medium and low temperature zone 204b, and the residual heat of the medium and low temperature molten salt is used to preheat it to the second preset temperature (e.g., 80°C). This is low temperature preheating.

[0056] The high-temperature water, after its first reheating, is transported back to the main line of the city's heating network 300, directly raising the water temperature. The return water, after its second preheating, is then transported back to the heating company. This means that the heating company only needs to consume less fuel to reheat the water to the supply temperature, significantly reducing the heating company's energy consumption.

[0057] This embodiment greatly improves the overall efficiency of the entire thermal system through graded heat storage and heat replenishment, realizing the graded and tiered utilization of abandoned thermal energy.

[0058] Example 3: A system with emergency and backup heating capabilities

[0059] Reference Figure 2 As shown, this embodiment adds an emergency direct compensation circuit and a backup heat source based on embodiment 1 or 2, which greatly enhances the system's reliability and ability to respond to emergencies.

[0060] In this embodiment, a backup heat replenishment component 400 is added to the system. This component includes an air source heat pump 401 and an electrode boiler 402. The two can be switched to the original heat replenishment circuit via a valve group. At the same time, the first electric heater 202 and the second electric heater 203 can be directly connected to the urban heating network 300 via a three-way valve and a bypass pipeline to form an emergency direct replenishment circuit.

[0061] In addition to performing conventional control, the bidirectional controller 201 also monitors the total heat storage capacity (SOC) of the thermal storage device 204 and the instantaneous heat load demand of the urban heating network 300 in real time.

[0062] Emergency direct subsidy mode: When the urban heating network load increases sharply, requiring immediate heat replenishment, but the medium temperature of the heat storage device 204 is low (such as when it is first started) and cannot immediately provide sufficient heat, the controller can switch valves to activate the emergency direct subsidy circuit. At this time, the photovoltaic curtailment directly drives the first electric heater 202 and the second electric heater 203 to instantly heat the pipeline medium flowing through its internal pipes, bypassing the heat storage device and achieving rapid response.

[0063] Backup heating mode: When the amount of abandoned photovoltaic power is insufficient, causing the heat storage capacity of the heat storage device 204 to fall below the first threshold (e.g., 30%), and the predicted heat load is higher than the second threshold, the controller will activate the backup heating component 400.

[0064] At night or during periods of higher temperature, the air source heat pump 401, which has a higher coefficient of performance (COP), is prioritized for supplemental heating to save energy.

[0065] In extreme cases where a large amount of heat energy is urgently needed, the electrode boiler 402, which has a fast heating speed and high power, is started to provide peak heat supplementation.

[0066] This embodiment, through multiple safeguard mechanisms, ensures that the system can provide stable and reliable heat replenishment at critical moments when the urban heating network needs heat the most, significantly improving the safety and stability of the entire heating system.

[0067] The photovoltaic curtailment and off-peak electricity from the high-voltage grid side enter the electric-thermal co-heating unit 200 via the AC side through the station service transformer 103.

[0068] Monitor the power generation output status of the centralized photovoltaic power station's power generation unit 100 and identify curtailed photovoltaic power;

[0069] The first electric heater 202 and the second electric heater 203 are controlled by the bidirectional controller 201 to start / stop and control the power.

[0070] During off-peak and abandoned electricity periods, the first electric heater 202 uses off-peak and abandoned electricity to heat the thermal storage device 204, converting electrical energy into thermal energy and storing it in the thermal storage device 204.

[0071] The temperature of the supply and return water pipe network of the urban heating network 300 is monitored by temperature sensing modules (first temperature sensing module 207 and second temperature sensing module 208), and the data is transmitted to the bidirectional controller 201.

[0072] During the heating season, the water supply and return networks of the urban heating network 300 are supplemented with heat through the heat storage device 204, and the water supply that does not meet the temperature standard is introduced into the high temperature zone 204a of the heat storage device 204 for the first supplementary heating.

[0073] The return water after the user has released heat is introduced into the low-temperature zone 204b of the heat storage device 204 for a second heat replenishment;

[0074] The reheated water is then transported to the city's heating network 300, and the preheated return water is transported back to the heating company.

[0075] When the thermal storage device 204 cannot meet the heat replenishment demand (for example, when the photovoltaic absorption rate is high and there is not enough photovoltaic power to fully heat the thermal storage device), the temperature sensing device on the supply and return water pipeline detects that the water temperature is lower than the set value (supply water is lower than 110℃ and return water is lower than 70℃). The second electric heater 203 is started through the bidirectional controller 201 to directly heat the water supply network using the power grid. The power and start / stop of the second electric heater 203 are adjusted according to the supply and return water temperatures.

[0076] It should be noted that while the preferred embodiments of this utility model are provided in the specification and accompanying drawings, this utility model can be implemented in many different forms and is not limited to the embodiments described in this specification. These embodiments are not intended to impose additional limitations on the content of this utility model; their purpose is to provide a more thorough and comprehensive understanding of the disclosure of this utility model. Furthermore, the above-mentioned technical features can be combined with each other to form various embodiments not listed above, all of which are considered to be within the scope of this utility model specification. Moreover, those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A photovoltaic power plant curtailment utilization system that coordinates power grid and heating network, characterized in that, It includes a centralized photovoltaic power plant power generation unit (100), an electric and thermal synergistic heating unit (200), and an urban heating network (300). The centralized photovoltaic power station power generation unit (100) includes photovoltaic modules (101), inverters (102) and station transformers (103), which are used to convert light energy into electrical energy and transmit it to the power grid; The electrothermal co-heating unit (200) includes a bidirectional controller (201), a first electric heater (202), a second electric heater (203), a heat storage device (204), a water supply pump (205), a return water pump (206), a first temperature sensing module (207), and a second temperature sensing module (208). The bidirectional controller (201) is used to control the power distribution of the first electric heater (202) and the second electric heater (203) and the start / stop of the water supply pump (205) and the return water pump (206) according to the medium temperature of the thermal storage device (204) and the water supply temperature of the urban heating network (300). The first electric heater (202) is used to convert electrical energy into heat energy and store it in the thermal storage device (204), and the second electric heater (203) is used to directly heat the urban heating network (300). The heat storage device (204) is connected to the water supply network of the urban heating network (300) via the water supply pump (205) and the water supply network of the urban heating network (300). The heat storage device (204) is also connected to the return water pump (206) and the return water network of the urban heating network (300). The first temperature sensing module (207) is used to monitor the water temperature of the water supply network of the urban heating network (300), and the second temperature sensing module (208) is used to monitor the water temperature of the return water network of the urban heating network (300). The bidirectional controller (201) is also signal-connected to the first temperature sensing module (207) and the second temperature sensing module (208).

2. The photovoltaic power plant curtailment utilization system in coordination with the power grid and heating network according to claim 1, characterized in that, The heat storage device (204) is a solid heat storage device or a molten salt heat storage device, and the heat storage device (204) includes a high temperature region (204a) and a medium and low temperature region (204b).

3. The photovoltaic power plant curtailment utilization system in coordination with the power grid and heating network according to claim 2, characterized in that, The high-temperature zone (204a) of the heat storage device (204) is used to perform the first supplementary heating on the water supply of the urban heating network (300) and raise its temperature to the first preset temperature; the medium-low temperature zone (204b) of the heat storage device (204) is used to perform the second supplementary heating on the return water of the urban heating network (300) and preheat its temperature to the second preset temperature.

4. The photovoltaic power plant curtailment utilization system in coordination with the power grid and heating network according to claim 3, characterized in that, The first preset temperature is 120℃-130℃, and the second preset temperature is 80℃.

5. The photovoltaic power plant curtailment utilization system in coordination with the power grid and heating network according to claim 1, characterized in that, When the medium temperature of the heat storage device (204) is lower than the preset requirement value, the bidirectional controller (201) controls the first electric heater (202) to directly provide emergency heat replenishment to the pipeline medium flowing through the heat replenishment circuit.

6. The photovoltaic power plant curtailment utilization system in coordination with the power grid and heating network according to claim 5, characterized in that, The first electric heater (202) and the second electric heater (203) are both connected to the pipeline of the urban heating network (300) to form an emergency direct compensation circuit.

7. The photovoltaic power plant curtailment utilization system in coordination with the power grid and heating network according to claim 1, characterized in that, It also includes a backup heating component (400), which is used to connect to the heating circuit for auxiliary heating.

8. The photovoltaic power plant curtailment utilization system in coordination with the power grid and heating network according to claim 7, characterized in that, The backup heat supply component (400) includes an air source heat pump (401) and an electrode boiler (402), the air source heat pump (401) and / or the electrode boiler (402) being connected to the heat supply circuit.

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