Renewable energy power supply system of transformer substation

Abstract

The utility model discloses a renewable energy power supply system of a transformer station, which comprises two alternating current power supply lines, a renewable energy power supply line and a direct current bus, the two alternating current power supply lines comprise an I # alternating current bus and a 2 # alternating current bus, the I # alternating current bus is connected with a first one-way conduction voltage reduction unit through a first AC / DC converter, and the I # alternating current bus is connected with a second one-way conduction voltage reduction unit through a second AC / DC converter. The first one-way conduction step-down unit is connected with the direct-current bus, the 2 # alternating-current bus is connected with the second one-way conduction step-down unit through the second AC / DC converter, and the second one-way conduction step-down unit is connected with the direct-current bus; the renewable energy power supply line comprises renewable energy power generation equipment and an energy storage device which are connected with the direct current bus. The novel transformer substation is high in renewable energy utilization efficiency.

Description

Technical Field

[0001] This utility model relates to the field of substation design, and in particular to a renewable energy power supply system for substations. Background Technology

[0002] Renewable energy sources, such as wind and solar power, are being adopted more and more widely due to their advantages of being pollution-free and renewable. Renewable energy is typically used for residential purposes, such as residential solar power, or for large-scale solar and wind power generation.

[0003] However, there are currently no precedents for utilizing renewable energy in substations. This is mainly because substations require uninterrupted power supply and have extremely high requirements for power quality and reliability. Solar or wind power, on the other hand, are limited by factors such as weather conditions and cannot guarantee a stable and reliable power output. Utility Model Content

[0004] To address the shortcomings of existing technologies, this invention provides a renewable energy power supply system for substations.

[0005] A substation renewable energy power supply system includes two AC power supply lines, one renewable energy power supply line, and one DC bus. The two AC power supply lines include an AC bus #1 and an AC bus #2. The AC bus #1 is connected to a first unidirectional step-down unit via a first AC / DC converter, and the first unidirectional step-down unit is connected to the DC bus. The AC bus #2 is connected to a second unidirectional step-down unit via a second AC / DC converter, and the second unidirectional step-down unit is connected to the DC bus. The renewable energy power supply line includes renewable energy generation equipment and energy storage devices connected to the DC bus.

[0006] Optionally, the output voltage of the renewable energy power supply line is equal to the rated voltage of the DC bus, and the output voltage of the two AC power supply lines is lower than the rated voltage of the DC bus; a first control unit and a second control unit are provided on the two AC power supply lines, the first control unit is connected to the first AC / DC converter and the first unidirectional buck unit, and the second control unit is connected to the second AC / DC converter and the second unidirectional buck unit; the first unidirectional buck unit or the second unidirectional buck unit is an uncontrolled unidirectional buck unit; the uncontrolled unidirectional buck unit is composed of multiple diodes connected in series; the uncontrolled unidirectional buck unit is composed of multiple diodes connected in parallel; the uncontrolled unidirectional buck unit is composed of multiple diodes and resistors connected in series; the first unidirectional buck unit or the second unidirectional buck unit is a controlled unidirectional buck unit; the controlled unidirectional buck unit is composed of multiple transistors connected in series or parallel; the controlled unidirectional buck unit is composed of multiple transistors and diodes connected in series.

[0007] The beneficial effects of this new technology are: it solves the shortcomings of traditional substations, such as low renewable energy utilization rates and poor integration of photovoltaic and other renewable energy sources with substation buildings, and provides a building-energy integration technology solution with high renewable energy utilization, low loss, and high reliability. This technology solution reduces energy losses caused by frequent AC / DC and DC / AC conversions through the construction of DC buses and the application of DC equipment. By rationally configuring the source, load, and storage ratio within the substation, it effectively improves energy utilization efficiency, promotes the application of renewable energy in substations, and guides substation buildings to gradually achieve near-zero energy consumption. Attached Figure Description

[0008] Figure 1 This is a schematic diagram of the power supply system.

[0009] Figure 2 This is a schematic diagram of the structure of an uncontrolled unidirectional buck converter;

[0010] Figure 3 This is a schematic diagram of a controlled unidirectional buck converter. Detailed Implementation

[0011] To make the above-mentioned objects, features, and advantages of this invention more apparent and understandable, the specific embodiments of this invention will be described in detail below with reference to the accompanying drawings, making the above-mentioned and other objects, features, and advantages of this invention clearer. In all the drawings, the same reference numerals indicate the same parts. The drawings are not intentionally drawn to scale; the focus is on illustrating the main idea of ​​this invention.

[0012] like Figure 1As shown, this novel substation renewable energy power supply system includes two AC power supply lines, one renewable energy power supply line, and one DC bus. Figure 1 The two AC power supply lines include AC bus #1 and AC bus #2, both 380 / 220V AC buses. AC bus #1 is connected to a first unidirectional step-down unit via a first AC / DC converter. The first unidirectional step-down unit is connected to the DC bus. AC bus #2 is connected to a second unidirectional step-down unit via a second AC / DC converter. The second unidirectional step-down unit is connected to the DC bus. The DC bus can be, for example, a 750V DC bus. The renewable energy power supply lines include renewable energy generation equipment and energy storage devices connected to the DC bus, such as solar panels or wind turbines. Various DC electrical appliances for the substation are mounted on the DC bus, such as lighting equipment, air conditioning equipment, and computer systems for the substation.

[0013] The core of this invention lies in maximizing the use of renewable energy to power the substation while ensuring a stable and reliable power supply. Therefore, in this invention, the output voltage of the renewable energy power supply line is equal to the rated voltage of the DC bus, while the output voltage of the two AC power supply lines is lower than the rated voltage of the DC bus. For example, if the rated voltage of the DC bus is 750V, then the output voltage of the energy storage device or renewable energy power generation equipment is 750V, while the output voltage of the two AC power supply lines can be, for example, 740V.

[0014] A unidirectional step-down unit can be used to reduce the output voltage of AC power supply lines, thereby making the output voltage of the two AC power supply lines lower than the rated voltage of the DC bus. The current flow direction of the unidirectional step-down unit is unidirectional, flowing only from the AC bus to the DC bus.

[0015] During operation, when the voltage supplied by the renewable energy power supply line is greater than or equal to the rated voltage, the output voltage of the two AC power supply lines is lower than the rated voltage of the DC bus. In this case, the load is powered by the renewable energy power supply line; due to the presence of the unidirectional step-down unit, current will not flow backward to the AC bus. When the voltage supplied by the renewable energy power supply line is lower than the output voltage of the AC power supply line, for example, when photovoltaic power generation decreases at night, the unidirectional step-down unit turns on, and the AC power supply line supplies power to the DC bus. For DC bus loads, they can be connected to the load via, for example, a DC / DC unit, to convert the DC bus voltage to the voltage required for their own operation.

[0016] Furthermore, a first control unit and a second control unit can be installed on the two AC power supply lines. The first control unit is connected to the first AC / DC converter and the first unidirectional buck converter, and the second control unit is connected to the second AC / DC converter and the second unidirectional buck converter. The first control unit / second control unit is used to control the operation of the first AC / DC converter, the second AC / DC converter, the first unidirectional buck converter, and the second unidirectional buck converter.

[0017] For the first unidirectional buck unit or the second unidirectional buck unit, it can be a controlled unidirectional buck unit or an uncontrolled unidirectional buck unit. Figure 2 This is a schematic diagram of an uncontrolled unidirectional buck converter. The uncontrolled unidirectional buck converter can use, for example, a diode. The AC / DC converter is connected to the DC bus through the diode. The diode has unidirectional conduction characteristics and generates a voltage drop across the diode when it is conducting. Figure 2 Figure A in the diagram shows an uncontrolled unidirectional buck converter consisting of two or more diodes connected in series. Figure 2 Figure B in the diagram shows an uncontrolled unidirectional buck converter consisting of two or more diodes connected in series with a resistor. Figure 2 In diagram C, an uncontrolled unidirectional buck converter is formed by two or more diodes connected in parallel.

[0018] For a controlled unidirectional buck converter, it may include transistors, MOSFETs, etc. When a transistor or MOSFET is turned on, a voltage drop is formed between the collector (source) and emitter (drain). When a transistor is used, its base is controlled by the control unit. When the DC bus voltage is lower than the rated voltage, the control unit triggers the transistor to turn on, thereby supplying power to the substation through the AC bus. Figure 3 Figure A in the diagram shows a controlled unidirectional buck converter consisting of a single transistor. Figure 3 Figure B in the diagram shows a controlled unidirectional buck converter consisting of two or more transistors connected in series. Figure 3 In diagram C, a controlled unidirectional buck converter is formed by two or more transistors connected in parallel. Figure 3 The diagram in Figure D shows an uncontrolled unidirectional buck converter consisting of a transistor and a diode connected in series.

[0019] In the above scheme, the loads on the DC bus of the substation prioritize the use of renewable energy. AC bus power is only used when the output of renewable energy decreases and cannot meet the load voltage requirements. This significantly improves the utilization rate of renewable energy. Furthermore, when the output of renewable energy decreases, the AC bus can immediately supply power to the DC bus without causing an intermediate power outage, thus improving the reliability of the substation's power supply. This approach increases the utilization rate of new energy sources while reducing building energy consumption within the substation.

[0020] The 220kV indoor substation can accommodate approximately 200kW of rooftop photovoltaic power, with a DC side capacity of 210kWp and a capacity-to-distribution ratio of 1.05. It utilizes 420 P-type 500Wp monocrystalline bifacial double-glass photovoltaic modules and four 50kW converters. Upon completion, the first-year power generation is estimated at approximately 216,600 kWh, with an equivalent utilization of 1083 hours. The total power generation over 25 years is projected to be approximately 5,070,000 kWh, with an average annual power generation of 202,800 kWh and an annual equivalent utilization of 1014 hours.

[0021] Based on the long-term load conditions within the station, calculations were performed to ensure no curtailment of solar power and no grid connection. Two 186kW / 372 kWh cabinet-type energy storage systems were installed within the station, operating on a daily charge-discharge cycle. Charging occurs for 4-6 hours daily during peak solar power generation, with discharging occurring at other times. This solution achieves no curtailment of solar power, no grid connection of solar power, and full utilization of green electricity. In summer, solar power generation can account for 70% of the building's total electricity consumption, and annual power generation can account for 40%-50% of annual electricity consumption. The rational allocation of energy storage not only effectively solves the complexity of management and the problem of solar curtailment but also further improves the utilization rate of new energy sources, effectively reducing the building's dependence on external energy sources.

[0022] The substation is equipped with a 750V unipolar DC bus, which connects DC loads such as photovoltaic, lighting, energy storage, and air conditioning. Two sets of AC / DC modules, serving as backups for each other, are connected to two AC bus sections within the substation. This DC system achieves effective self-sufficiency between power sources, loads, and energy storage, while simultaneously improving the utilization of new energy sources. Furthermore, the energy storage can serve as a backup power source for the AC bus, thereby enhancing the power supply reliability of the substation's electrical system to a certain extent.

[0023] DC lighting control systems can adjust brightness according to required illuminance and the monitoring of object and personnel movement; reduce lighting power consumption and cost, save resources, extend light source life, and reduce luminaire maintenance workload;

[0024] The intelligent air conditioning control system monitors the ambient temperature and humidity through temperature and humidity sensors, controls the start and stop of the air conditioner, reduces energy consumption, and ensures that local overheating does not occur.

[0025] The photovoltaic aluminum-magnesium-manganese metal roofing panel system is used in the building envelope of substations. The photovoltaic modules are fixed on the aluminum-magnesium-manganese metal roofing panels, thereby utilizing renewable energy through the photovoltaic panels while avoiding the propagation of thermal bridges. It also provides sufficient space for the roof insulation layer and waterproof layer, playing a role in heat insulation, rainproofing, energy saving and consumption reduction.

[0026] Integrating renewable energy sources such as photovoltaics and wind power into substation construction and absorbing them locally within the substation building reduces substation energy consumption. Equipment capacity is determined based on operational energy consumption targets, and numerical simulation methods are used to determine the application scale of various renewable energy systems, including photovoltaics, geothermal energy, and solar thermal energy, to improve the energy efficiency of various electromechanical systems and terminals. While substation operating loads are relatively stable, the output of renewable energy sources is not stable and has limited output periods. To further improve the utilization rate of renewable energy, energy storage can be rationally configured based on energy technology and substation load conditions to further reduce building energy consumption.

[0027] Most of the energy-consuming equipment inside the substation buildings uses AC power distribution. Constructing a DC power distribution network after the integration of new energy sources can improve the utilization rate of these new energy sources, reduce energy conversion losses, and enhance operational reliability and safety.

[0028] The DC lighting control system adjusts brightness based on required illuminance and the monitoring of object and personnel movement; it reduces lighting power consumption and cost, saves resources, extends light source life, and reduces lamp maintenance workload; the intelligent air conditioning control system monitors ambient temperature and humidity through temperature and humidity sensors, controls the start and stop of the air conditioning, reduces energy consumption, and ensures that local overheating does not occur.

[0029] The photovoltaic aluminum-magnesium-manganese metal roofing panel system is used in the building envelope of substations. The photovoltaic modules are fixed on the aluminum-magnesium-manganese metal roofing panels, thereby utilizing renewable energy through the photovoltaic panels while avoiding the propagation of thermal bridges. It also provides sufficient space for the roof insulation layer and waterproof layer, playing a role in heat insulation, rainproofing, energy saving and consumption reduction.

[0030] Many specific details have been set forth in the foregoing description to provide a full understanding of the present invention. However, the above description is merely a preferred embodiment of the present invention, and the present invention can be implemented in many other ways different from those described herein. Therefore, the present invention is not limited to the specific embodiments disclosed above. Furthermore, any person skilled in the art can make many possible variations and modifications to the present invention, or modify it into equivalent embodiments, using the methods and techniques disclosed above, without departing from the scope of the present invention. Any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention, without departing from the content of the present invention, shall still fall within the protection scope of the present invention.

Claims

1. A renewable energy power supply system for a substation, characterized in that, It includes two AC power supply lines, one renewable energy power supply line, and one DC bus. The two AC power supply lines include AC bus #1 and AC bus #2. AC bus #1 is connected to a first unidirectional buck converter via a first AC / DC converter, and the first unidirectional buck converter is connected to the DC bus. AC bus #2 is connected to a second unidirectional buck converter via a second AC / DC converter, and the second unidirectional buck converter is connected to the DC bus. The renewable energy power supply line includes renewable energy generation equipment and energy storage devices connected to the DC bus.

2. The renewable energy power supply system according to claim 1, characterized in that, The output voltage of the renewable energy power supply line is equal to the rated voltage of the DC bus, and the output voltage of the two AC power supply lines is lower than the rated voltage of the DC bus.

3. The renewable energy power supply system according to claim 2, characterized in that, The two AC power supply lines are equipped with a first control unit and a second control unit. The first control unit is connected to the first AC / DC converter and the first unidirectional buck converter, and the second control unit is connected to the second AC / DC converter and the second unidirectional buck converter.

4. The renewable energy power supply system according to claim 3, characterized in that, The first unidirectional buck unit or the second unidirectional buck unit is an uncontrolled unidirectional buck unit.

5. The renewable energy power supply system according to claim 4, characterized in that, The uncontrolled unidirectional buck converter consists of multiple diodes connected in series.

6. The renewable energy power supply system according to claim 4, characterized in that, The uncontrolled unidirectional buck converter consists of multiple diodes connected in parallel.

7. The renewable energy power supply system according to claim 4, characterized in that, The uncontrolled unidirectional buck converter consists of multiple diodes and resistors connected in series.

8. The renewable energy power supply system according to claim 3, characterized in that, The first unidirectional buck unit or the second unidirectional buck unit is a controlled unidirectional buck unit.

9. The renewable energy power supply system according to claim 8, characterized in that, The controlled unidirectional buck converter consists of multiple transistors connected in series or parallel.

10. The renewable energy power supply system according to claim 8, characterized in that, The controlled unidirectional buck converter consists of multiple transistors and diodes connected in series.

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