CN201515334U - Solar photovoltaic generating system for power supply transformer substation - Google Patents

Abstract

A solar photovoltaic power generation system used in power supply substation, the DC voltage generated by the solar battery array is output to the DC distribution box, and then output to the control switching device. The control switching device has two functions of grid-connected power generation and DC charging; the control switching device is respectively connected with the photovoltaic grid-connected inverter and the photovoltaic charging controller; the output terminal of the photovoltaic grid-connected inverter is connected in parallel with the low-voltage terminal of the transformer in the substation , to send electric energy into the mains grid; the photovoltaic charge controller is connected to the battery, and the battery is connected to the DC system in the substation, and supplies power to the DC system when the AC grid of the substation loses power. The utility model has the functions of DC charging and grid-connected power generation. The system operates in grid-connected mode under normal conditions, and can be used as a DC charger when the AC power of the substation is lost. The utility model can enhance the power supply reliability of the DC system in the substation, reduce the power consumption of the load in the substation to the power grid, and even realize zero loss of the substation.

Description

A solar photovoltaic power generation system for power supply substation

technical field

The utility model relates to a grid-connected solar photovoltaic power generation system, in particular to a solar photovoltaic power generation system with the functions of DC charging and grid-connected power generation for power supply transformation.

Background technique

The photovoltaic power generation system converts the energy from the sun into electrical energy through solar cells, which can be sent to the grid or stored in batteries, thus providing human beings with inexhaustible energy. In addition, solar energy has incomparable advantages such as safety and reliability, no need to consume fuel, easy maintenance, random scale, and can be combined with buildings.

Photovoltaic grid-connected power generation technology is a new technology that has emerged in recent years. Compared with traditional kerosene and oil power, it has many advantages such as environmental protection, no energy consumption, and reusability. It will be the focus of energy strategy development in the future. Now foreign solar photovoltaic power generation technology and large-scale operation have matured. The United States, Japan, and Germany have established megawatt-level photovoltaic power stations, and their building integrated photovoltaic power generation (BIPV), including solar roof photovoltaic systems, has become quite popular. China's photovoltaic power generation industry started in the 1970s and entered a period of steady development in the mid-1990s. Now, the output of solar cells and modules has steadily increased year by year, and the photovoltaic power generation industry has developed rapidly.

At present, there are more grid-connected photovoltaic power generation systems on the market, or photovoltaic systems with independent power generation. The former cannot be connected to the grid when the power grid fails, and the power generation is greatly restricted by the grid; the latter is a long-term occurrence. In cloudy and rainy weather, electric energy cannot be output in time, and in severe cases, the battery in the energy storage device may be damaged.

Contents of the invention

The purpose of this utility model is to provide a solar photovoltaic system for a power supply substation with the functions of DC charging and grid-connected power generation. The system operates in grid-connected mode when the system is normal, and the system can be used as a DC charger when the AC power of the substation loses power. , to realize the integration of DC charging and grid-connected power generation, so that DC power generation and grid-connected power generation can be switched automatically or manually.

In order to achieve the above object, the technical solution adopted by the utility model is:

A solar photovoltaic power generation system for power supply and transformation, including: a solar cell array, the solar cell array includes solar cell components, a junction box and a support, the solar cell components are connected through electrical connections, and the solar energy is directly converted into electrical energy, and the solar cell The DC voltage generated by the array is output through the junction box, which is characterized in that: the DC voltage generated by the solar cell array is output to the DC distribution box through the junction box; the DC distribution box receives the DC voltage generated by the solar cell array, and is transformed into a constant voltage after isolation. The DC voltage is output to the control switching device, and the control switching device sets the switching of two functions of grid-connected power generation and DC charging; the control switching device is connected with the photovoltaic grid-connected inverter and the photovoltaic charging controller respectively; the output of the photovoltaic grid-connected inverter The terminal is connected in parallel with the low-voltage terminal of the transformer in the substation through the power distribution cabinet, and the electric energy is sent to the mains grid through the transformer; the photovoltaic charging controller is connected with the battery, controls the solar battery to charge the battery, and at the same time controls the overcharge and overdischarge of the battery. Protection; the battery is connected to the DC system in the substation, and the battery stores solar photovoltaic power, and supplies power to the DC system in the substation when the AC grid in the substation loses power.

According to the solar photovoltaic power generation system used for power supply and transformation, it is characterized in that: the system also includes an independent detection system, which is used to detect the operating conditions of the grid-connected power station, including detecting the operating parameters of the power station and monitoring environmental parameters , the detection system uses the engineering control computer to collect data, display various working states and operating parameters, and complete various data communications.

According to the solar photovoltaic power generation system used for power supply and transformation, it is characterized in that: the control switching device includes: manual independent grid-connected power generation, manual DC charging, and automatic grid-connected power generation/DC charging three switching states; Under normal circumstances, the control switching device is in the state of automatic grid-connected power generation/DC charging switching; (1) Manual DC charging: the DC charging switch is closed, other switches are turned off, only the photovoltaic charging controller is working, and the battery can be charged ;(2) Manual independent grid-connected power generation: the grid-connected power generation switch is closed, other switches are turned off, only the photovoltaic grid-connected inverter works, and grid-connected power generation; (3) Automatic grid-connected power generation/DC charging: automatic switching The switch is closed, other switches are turned off, the sampling port inputs 220VAC, and when the AC mains is normal, the photovoltaic grid-connected inverter works and generates grid-connected power; when the AC mains fails, after a delay, the photovoltaic grid-connected inverter stops Work, the photovoltaic charge controller starts to work to charge the battery.

The photovoltaic power generation system used in the power supply transformation of the utility model has the functions of DC charging and grid-connected power generation. The cabinet is connected in parallel with the low-voltage end of the transformer (220V/380V) in the substation, and the generated electric energy is sent to the grid through the transformer for direct use by the user, which increases the utilization rate of the photovoltaic power station and enables the photovoltaic power station to have the function of grid-connected power generation. On the other hand, it can In the case of AC power failure, the photovoltaic charging controller charges the battery, which can then supply power to the DC system inside the substation, increasing the reliability of the DC system of the substation.

The solar photovoltaic power generation system used in the power supply substation of the utility model has the functions of DC charging and grid-connected power generation. The system operates in grid-connected mode under normal conditions. When the AC power of the substation is lost, the system can be used as a DC charger. This realizes the integration of DC charging and grid-connected power generation, so that DC power generation and grid-connected power generation can be switched automatically or manually.

Description of drawings

Fig. 1 is a schematic diagram of the utility model solar photovoltaic power generation system.

Fig. 2 is a schematic diagram of the control switching device in the utility model.

Fig. 3 is a wiring diagram of the control switching device in the utility model.

Fig. 4 is a main circuit diagram of the photovoltaic grid-connected inverter SG5K-C in the utility model.

Detailed ways

Below in conjunction with accompanying drawing and specific embodiment the utility model is further described:

The solar photovoltaic power generation system used in the power supply transformation of the utility model uses solar cell arrays to convert solar energy into direct current, and then converts the direct current generated by solar energy into 50 Hz, 220V/380V alternating current through a DC/AC photovoltaic grid-connected inverter. The output end of the photovoltaic grid-connected inverter is connected in parallel with the low-voltage end (220V/380V) of the transformer in the substation through the power distribution cabinet, and the generated electric energy is sent to the grid through the transformer.

The solar photovoltaic independent power generation system uses the solar cell array to output electric energy under the sunlight, and charges the battery pack through the DC distributor and photovoltaic charge controller to supply power to the DC load. In continuous cloudy and rainy days, when the power generated by the photovoltaic cell cannot meet the power supply to the load, the battery can continue to supply power to the load through the photovoltaic charge controller.

The photovoltaic power generation system of the utility model mainly includes a solar battery array, a DC distribution box, a control switching device, a photovoltaic charging controller, a storage battery, an independent detection system, etc., wherein:

The solar cell array is composed of photovoltaic cell components through a certain electrical connection method, which directly converts sunlight energy into electrical energy, and through the maximum power point, makes the photovoltaic cell in the state of maximum power output, and directly outputs the DC voltage generated by the solar cell array to the DC distribution box;

The DC distribution box receives the DC voltage generated by the solar cell array, and converts it into a constant DC voltage after isolation and outputs it to the control switching device;

The control switching device mainly completes the switching of the two functions of grid-connected power generation and DC charging; the control switching device can be switched manually or automatically. Among them, manual switching can be used for grid-connected power generation or DC charging alone; in the automatic switching state, the system operates in grid-connected power generation mode. If there is an AC power loss, in order to increase the reliability of the DC system, the photovoltaic power station As a backup DC charger to charge the DC system of the substation. The automatic switching function in this system is to perform automatic switching by detecting whether the AC power is lost.

The photovoltaic charging controller is connected to the energy storage device, which can control the solar battery to charge the battery, and at the same time, the controller protects the battery from overcharging and overdischarging.

The battery is an energy storage device used to store solar photovoltaic power. When the AC power grid fails to provide power for the DC system in the substation, the battery supplies power to the DC system of the substation to ensure the reliability of the DC system.

The independent detection system is an independent detection system that is used to detect the operating conditions of the grid-connected power station, including detecting the operating parameters of the power station (voltage, current, power, frequency, power generation, carbon dioxide emission reduction, etc.) and monitoring environmental parameters (sunshine , wind speed, wind direction, ambient temperature). The detection system uses industrial computer (engineering control computer) to collect data, uses 37' large-screen LCD TV to display various working states and operating parameters, and completes various data communications.

Specific examples:

The utility model aims at the defects that long-term continuous charging and discharging of the accumulator will affect the service life of the accumulator, and that the solar energy resource will be wasted if it is only used for DC charging. In the grid-connected operation mode, the utility model can automatically switch to the DC charging operation mode if the AC grid loses power; and the manual switching in the control switching device can realize independent grid-connected power generation or independent DC charging.

The utility model determines the specific configuration of the photovoltaic module according to the battery charging requirements of the DC system of the substation, taking into account the working conditions of the grid-connected inverter, and combining the meteorological information of the installation site. The utility model adopts ATM-175 monocrystalline silicon solar cell components, and adopts a square array of photovoltaic modules with 9 strings and 3 parallels, and the square array needs 27 components in total.

According to the power transmission requirements of the power supply substation, the utility model determines the main parameters of solar cell components, photovoltaic charging controllers, DC-AC inverter equipment (grid-connected inverters), and photovoltaic power station detection systems, especially when selecting When setting the grid-connected inverter, the distortion rate of the total current meets the requirements of the power supply station. Finally, the theoretical calculation and actual power supply analysis of solar photovoltaic power generation are carried out.

As shown in Figure 1, the utility model includes a solar battery array, a DC power distribution box, a control switching device, a photovoltaic grid-connected inverter, a photovoltaic charging controller, a storage battery, and an independent detection system.

The solar cell array is composed of solar cell modules, junction boxes and brackets. It is composed of solar cell components through a certain electrical connection method, directly converts solar energy into electrical energy, and outputs the DC voltage generated by the solar cell array to the DC distribution box through the junction box.

The DC distribution box receives the DC voltage generated by the solar cell array, and converts it into a constant DC voltage after isolation and outputs it to the control switching device;

The control switching device is the core part of the utility model, which mainly includes manual independent grid-connected power generation, manual DC charging, and automatic grid-connected power generation/DC charging.

According to specific needs, independent grid-connected power generation or independent DC charging can be performed manually. As shown in Figure 2, the command switch has three states, "DC", "grid-connected" and "automatic". Under normal circumstances, the system is in the state of automatic switching.

(1) The DC charging switch is closed (other switches are disconnected): only the photovoltaic charging controller works, and the battery can be charged.

(2) The grid-connected power generation switch is closed (other switches are disconnected): only the photovoltaic grid-connected inverter works, and the grid-connected power generation.

(3) The automatic transfer switch is closed (other switches are disconnected): the sampling port inputs 220VAC, and when the AC mains is normal, the photovoltaic grid-connected inverter works and grid-connected power generation. When the AC power fails, after a delay, the photovoltaic grid-connected inverter stops working, and the photovoltaic charging controller starts working to charge the battery.

The independent detection system is used to detect the operating status of the grid-connected power station, including detecting the operating parameters of the power station (voltage, current, power, frequency, power generation, carbon dioxide emission reduction, etc.) and monitoring environmental parameters (sunshine, wind speed, wind direction, ambient temperature). The detection system uses industrial computer (engineering control computer) to collect data, uses 37' large-screen LCD TV to display various working states and operating parameters, and completes various data communications.

The manufacturer, model and some parameters of each part of the device are attached below.

(1) Solar cell module

Manufacturer: Shandong Angli Tiansheng Photovoltaic Technology Co., Ltd.

Model: ATM-175

Its main parameters are as follows:

·Battery material: monocrystalline silicon;

Battery composition: 72 monocrystalline silicon cells are arranged in an orderly form and connected in series

Package structure: glass/battery/metal frame;

·Meet the IEC1215 standard;

·Nominal power: 180W;

Open circuit voltage: 44.4V;

Short-circuit current: 5.3A;

Quantity: 27 pieces;

· Working environment temperature: -40℃～+70℃;

·Total power of solar battery: 4860W;

· Working life of solar cell array: ≥25 years;

(2) Photovoltaic charge controller

Manufacturer: Hefei Sunshine Power Supply Co., Ltd.

Model: SD22050

Its main technical parameters are as follows:

Environmental requirements: working temperature -20℃～40℃;

Storage temperature -20℃～50℃;

Relative humidity below 95%;

Cooling method natural air cooling;

Dielectric strength 1min at DC500V;

Insulation resistance greater than 10MΩ;

System ground Negative ground.

·Measurement parameters: solar cell array input voltage, solar cell array input current, battery DC output current, battery voltage.

·Instructions: Overcharge and overdischarge protection instructions.

·Alarm: alarm when over discharge.

·Power/current control parameters: maximum allowable input power 11000W; maximum allowable input current 50A; maximum output current 50A.

(3) Photovoltaic grid-connected inverter (DC-AC inverter equipment)

Manufacturer: Hefei Sunshine Power Supply Co., Ltd.

Model: SG5K-C

Some working parameters are as follows:

DC optimal power tracking (MPPT) input voltage range: DC200V ~ DC450V;

Maximum array open circuit voltage: DC450V;

DC voltage ripple: Vpp≤10%;

Maximum DC input current: DC30A;

Maximum conversion efficiency: 95% (European efficiency 93%);

Maximum AC output power: 5KW;

Permissible grid frequency range: 49.8～50.2Hz;

Total current waveform distortion rate: THD≤3%;

Power factor: ≥0.98;

Protection functions: reverse polarity protection, short circuit protection, island effect protection, overheat protection, overload protection, grounding protection;

system communication

Communication interface: RS485 or CAN bus;

Grid monitoring: according to UL1741 standard.

(4) Industrial computer

Manufacturer: Advantech Technology Co., Ltd.

Model: ARK-3389

Some working parameters are as follows:

CPU: Intel Pentium M low voltage processor;

System Memory: One 200-pin SO-DIMM slot; supports DDR SDRAM up to 1GB;

Display: dynamic video memory up to 64MB; CRT interface;

Ethernet controller: 10/100MBps;

Watchdog timer and serial port;

Input voltage: DC12V ~ DC24V;

Working temperature: -20℃～60℃.

The above-mentioned embodiment is only to describe the preferred implementation of the present utility model, not to limit the design and protection scope of the present utility model. Various modifications and improvements made in the technical solution of the utility model shall fall within the scope of protection of the utility model.

Claims (3)

1. A solar photovoltaic power generation system used for power supply transformation, comprising: a solar cell array, the solar cell array includes a solar cell assembly, a junction box and a support, the solar cell assembly is connected by an electrical connection, and the solar energy is directly converted into electric energy, and the The DC voltage generated by the solar cell array is output through the junction box, which is characterized in that: the DC voltage generated by the solar cell array is output to the DC distribution box through the junction box; the DC distribution box receives the DC voltage generated by the solar cell array, and is transformed into The constant DC voltage is output to the control switching device, and the control switching device sets the switching of two functions of grid-connected power generation and DC charging; the control switching device is respectively connected with the photovoltaic grid-connected inverter and the photovoltaic charging controller; the photovoltaic grid-connected inverter The output end of the power distribution cabinet is connected in parallel with the low-voltage end of the transformer in the substation, and the electric energy is sent to the mains grid through the transformer; protection; the battery is connected to the DC system in the substation, and the battery stores solar photovoltaic power, and supplies power to the DC system in the substation when the AC grid in the substation loses power. 2. The solar photovoltaic power generation system used for power supply and transformation according to claim 1, characterized in that: the system also includes an independent detection system, which is used to detect the operating conditions of the grid-connected power station, including detecting the operation of the power station Parameters and monitoring environment parameters, the detection system uses engineering control computer to collect data, display various working status and operating parameters, and complete various data communication. 3. The solar photovoltaic power generation system for power supply and transformation according to claim 1 or 2, characterized in that: the control switching device includes: manually performing independent grid-connected power generation, manually performing DC charging, and automatically performing grid-connected power generation/ Three switching states of DC charging; under normal circumstances, the control switching device is in the state of automatic grid-connected power generation/DC charging switching; (1) Manual DC charging: DC charging switch is closed, other switches are off, and only photovoltaic charging control (2) Manually perform independent grid-connected power generation: the grid-connected power generation switch is closed, other switches are disconnected, only the photovoltaic grid-connected inverter works, and grid-connected power generation is performed; (3) Automatic grid-connected power generation Power generation/DC charging: the automatic switching switch is closed, other switches are disconnected, the sampling port inputs 220VAC, when the AC mains is normal, the photovoltaic grid-connected inverter works, and grid-connected power generation; when the AC mains fails, after a delay, The photovoltaic grid-connected inverter stops working, and the photovoltaic charging controller starts working to charge the battery.

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