3393 results about "Photovoltaic power station" patented technology

Improved techniques for photovoltaic power generation are described. Inverter failure is can be a significant problem in solar photovoltaic systems as it can lead to loss of opportunity to harvest energy. A solar photovoltaic (PV) power generation system is described comprising solar PV panels and power conditioning units. A dc power distribution bus is coupled to the solar PV panels and the power conditioning units to switchably share dc power from the solar PV panels between the power conditioning units. Power distribution controllers detect a faulty power conditioning unit and reroute power from a solar PV panel coupled to the faulty power conditioning unit to other power conditioning units via the dc distribution bus.

In large PV power plants, grounding of individual PV modules may lead to problems. The present invention overcomes such problems. The basis for the invention is a PV power plant comprising one or more PV generators, each comprising a PV string and an inverter with a DC input and an AC output. The PV string comprises at least one PV module and is electrically connected to the DC input of the inverter. The inverter comprises means for controlling the DC potential at the DC input depending on the DC potential at the AC output. The AC outputs of the inverters are coupled in parallel. The novel feature of the invention is that the PV power plant further comprises an offset voltage source, which controls the DC potential at the AC outputs. Thereby, the DC potential at the DC input will be indirectly controlled, and it is thus possible to ensure that the potentials with respect to ground at the terminals of the PV modules are all non-negative or all non-positive without grounding the PV modules. Ground loops can be avoided, and there is no need for the use of transformer-based inverters.

The invention discloses a performance prediction and fault alarm method for a photovoltaic power station. The method comprises the following steps of: a, setting the station of the power station; b, setting the operation mode of the power station; c, judging whether required real-time data or historical data exists or not; d, predicting the performance of the power station through an experience model if the state in the step a is that a new photovoltaic power station is required to be designed and the required real-time data or historical data in the step c does not exist, and predicting the performance of the power station through a data drive performance model if the required real-time data or historical data in the step c exists; e, predicting the performance of the power station through the data drive performance model or a polynomial regression model if the photovoltaic power station in the step a is operated and the required real-time data or historical data in the step c exists, and predicting the performance of the power station through the experience model if the required real-time data or historical data in the step c does not exist; f, comparing actual performance with the predicted performance, and performing fault alarm; and g, correcting the models on line by a Kalman filtering method and returning to the step c, and otherwise, directly returning to the step e. By the method, solar energy resources can be utilized to the maximum extent, and power utilization cost can be reduced; and the accuracy of performance prediction and fault diagnosis is improved.

The invention relates to a photovoltaic array fault diagnosis and early warning method comprising the following steps: combining an Elman nerve network optimized by a non-linear least square method and a decision tree with experience knowledge so as to form a fault diagnosis model; collecting present photovoltaic array operation data and meteorology data, and computing errors when compared with historical normal state data; using the fault diagnosis model to obtain the corresponding fault type and credibility when the error is bigger than a threshold; finally integrally evaluating so as to obtain the final fault type credibility, and selectively carrying out fault early warning according to the credibility values; updating a fault knowledge base according to the field actual measurement conditions. The method combines the LM-Elman nerve network and the decision tree with experience knowledge so as to built the fault diagnosis model, thus improving the history data sensitivity, providing better prediction effect when compared with a BP network, and improving the network convergence speed and training precision; the experience knowledge is supplemented, thus providing stronger robustness; the method can timely detect and diagnose, thus reducing fault incidence rate, and ensuring the photovoltaic power station to stably work.

The invention relates to a method for forecasting optical output power and electric energy production of a photovoltaic power station, belonging to the technical field of power generation and distribution. The method is characterized by comprising the following steps: on-site data acquisition-comparison with historic data-output of the forecasting result. The forecasting accuracy is so accurate that annual average between the forecasting result and actual result is no more than 5%; short-time forecasting, daily forecasting, weekly forecasting, monthly forecasting and annual forecasting can be carried out; as far as power grid dispatching is concerned, starting-up mode and operation mode of the photovoltaic power station and a conventional power station in a certain period can be reasonably arranged according to the forecasting, so that the power grid can operate stably, electric energy production of the photovoltaic power station can be improved, technical evidence and theoretic guidance can be provided for establishment of the large capacity photovoltaic power station, safe and efficient operation of the photovoltaic power station can be ensured and smooth implementation of national new energy strategy can be facilitated.

The invention relates to a large-scale photovoltaic power station inspection device based on double cameras carried on an unmanned aerial vehicle. The large-scale photovoltaic power station inspection device is mainly characterized in that a lightweight unmanned aerial vehicle or an unmanned system is used for performing inspection on the large-scale photovoltaic power station; and furthermore a thermal infrared imager and a visible light camera as detecting tools are mounted on the unmanned aerial vehicle for detecting a photovoltaic cell panel. An infrared image and a visible light image which are acquired by the double cameras are processed by a computer through an algorithm, thereby obtaining a conclusion whether the fault of the photovoltaic cell panel occurs. Furthermore a man-machine interaction interface is designed for displaying the image, the conclusion, etc. Compared with an existing fault monitoring method of the photovoltaic cell panel, the large-scale photovoltaic power station inspection device has advantages of improving reliability of a monitoring result, reducing manpower and physical resource, improving cost benefit, reducing work hour and realizing detection for invisible faults in the photovoltaic cell panel.

The invention provides an intelligent photovoltaic array washing car used for washing photovoltaic arrays of a large-scale ground photovoltaic power station. A washing head supporting and locating unit and a power unit are arranged on the head portion and the tail portion of a crawler base respectively, a water storage unit is arranged adjacent to the power unit, and a washing head unit is provided with range finder sensors used for measuring the distance between the washing head unit and solar cell panels; the washing head supporting and locating unit comprises a movable base capable of rotating and transversely moving and a working arm set provided with a main arm and an end arm, wherein the main arm and the end arm can pitch respectively; a water pump of a water supply unit is driven by a hydraulic motor; a computer is used as a control kernel of a main control module of an operation control unit; a pair of proportional directional valves of the hydraulic control unit controls two base crawler traveling motors, and other directional valves are electromagnetic directional valves controlled by the main control module. According to the intelligent photovoltaic array washing car, the position and the posture of the washing head unit relative to photovoltaic array panels and the position and the posture of a car body relative to the photovoltaic arrays can be automatically controlled, and the intelligent photovoltaic array washing car is intelligent, efficient, flexible in operation, high in adaptability, easy and convenient to operate, concise in structure and good in washing effect.

The invention discloses an inspection system and an implementation method for the electrical equipment of an unmanned aerial vehicle photovoltaic power station. The inspection system includes an airborne terminal, a ground terminal, and a wireless communication module. The camera or monitoring equipment collects the image data of the electrical equipment of the photovoltaic power station, and at the same time receives the control commands sent from the ground terminal to the airborne terminal; the ground terminal is set on the ground platform to process the data collected and sent back by the airborne terminal , to control the flight and shooting operations of the unmanned aerial vehicle on the ground; the wireless communication module completes the functions of transmitting flight control instructions, flight status data, and video return data between the airborne terminal and the ground terminal. The inspection system provides real-time high-definition viewing of infrared images and visible light images, which is convenient for timely resolution of faults. The images are analyzed on the ground side through pattern recognition. repair.

The invention discloses a photovoltaic array inspection method based on an unmanned aerial vehicle. In the method, the unmanned aerial vehicle is taken as a platform, and a high flexibility characteristic of the unmanned aerial vehicle is used so as to realize fault inspection of the unmanned aerial vehicle to a photovoltaic plate in a photovoltaic power station under a complex geographic environment. The unmanned aerial vehicle is carried with a high performance processor and two kinds of cameras (a visible light camera and an infrared camera), and simultaneously is carried with an accelerometer, a gyroscope, a magnetic induction meter and a GPS module. During an operation process, a GPS/SINS algorithm is used to calculate an outdoor flight position of the unmanned aerial vehicle so as to realize flight path control of the unmanned aerial vehicle. An image shot by the infrared camera is used to position a fault, and the visible light camera is used to carry out detailed shooting on the fault and return to a ground station so as to carry out subsequent processing. In the invention, autonomous inspection of the unmanned aerial vehicle to a photovoltaic array in the photovoltaic power station is realized so that usage of manpower and material resources is effectively reduced; and simultaneously because of flexibility of the unmanned aerial vehicle, photovoltaic array inspection under a complex environment becomes fast and high-efficient.

In the invention, the master station installed in the remote monitor center makes data communication with the far-end station installed in the solar PV power station; the master station sends the configuration instruction of the remote end monitor center to the far end station through the satellite repeater, and receives the data of far end station through the satellite repeater; the far end station is used for collecting the data about the running state of the PV power station, and converting the collected analog data into the digital data, and sends the digital data through antenna; under the control of the master station, the service channel sends the collected digital data to the master station through satellite; the administration computer processes the data and provides the data for the remote monitor center.

The invention discloses a photovoltaic power generation capacity/power prediction device which comprises a monitoring system, a data reading module, a data base, a data processing module, a weather information processing module and a prediction module. The data reading module reads photovoltaic power station data information monitored by the monitoring system in real time. The data base stores data information needed by prediction. The data processing module performs classification and classification result assessment on historical power generation capacity/power data and various weather data in the data base in a fuzzy cluster analysis method to obtain a similar day sample set. The weather information processing module processes weather forecast data. The prediction module comprises a BP prediction sub module, a grey prediction sub module and a support vector machine prediction sub module, and prediction results of all the prediction sub modules are combined to obtain the final prediction result. The photovoltaic power generation capacity/power prediction device combines functions of information monitoring and prediction to obtain the prediction result and provides a complete technical solution.

The present invention has disclosed an optimal control method for reactive voltage of wind power and photovoltaic power centralized grid connection in the field of wind power and photovoltaic power grid connection control technology, comprising: setting actuating stations used to control single wind power plant/photovoltaic power plant, setting substations used to control actuating stations and set master station used to control all the substations; master station calculates setting voltage reference U_ref of each substation; adopting 3σ method to process set voltage reference U_ref to obtain set voltage reference interval; regulating high-side voltage of substation to make it fall in set voltage reference interval; if high-side voltage of substation does not fall in set voltage reference interval, then regulating the equipment in wind power plant/photovoltaic power plant via actuating station. The present invention guides the actual operations of electric power system.

A real-time photovoltaic power plant control system and method of control for plant output, voltage regulation and/or power factor regulation. The system comprises a grid interface controller configured to receive power information from a power grid and provide commands for controlling at least one active or reactive power supplied to the power grid, a power plant controller configured to receive commands from the grid interface controller for and direct real-time output of the power plant, a plurality of local controllers connected to and controlled by the power plant controller, and a plurality of inverters each connected to supply power from at least one photovoltaic device to the power grid and arranged such that each local controller is connected to and controls at least one inverter, the inverters reporting status information in real-time back to the local controllers, and the local controller reporting status information in real-time back to the power plant controller.

The invention discloses a power adjustment method for a hybrid energy storage photovoltaic power station. In the operating process of the photovoltaic power station, voltage of a direct current bus of the photovoltaic power station and voltages of a super capacitor group and a lithium battery group which are connected with the direct current bus respectively through two bidirectional direct current/direct current (DC/DC) controllers are detected in real time, active power output of a photovoltaic power supply is detected in real time, and meanwhile power output values of the super capacitor group and the lithium battery group for fulfilling an electric energy quality adjustment and control aim of the photovoltaic power station or finishing a scheduling task are quickly calculated; and running states of the two bidirectional DC/DC controllers are controlled according to a calculation result, and thus a charging process and a discharging process of the super capacitor group and the lithium battery group can be controlled. By the method, the advantage of high energy density of a lithium battery and the advantages of long circulation service life and high power density of a super capacitor are given a full play, the problems of low electric energy quality and difficulty in participation in power grid scheduling which are caused by grid-connected running of the photovoltaic power station can be solved; and popularization and application of the photovoltaic power station are facilitated.

A method for breeding beef cattle and mutton sheep standardly on a large scale through photovoltaic facilities includes the four parts that first, a photovoltaic facility greenhouse is built, maize seedlings or high-quality green forage grass Zea mexicana is produced throughout the year to be used as green fodder of beef cattle and mutton sheep; second, the beef cattle and the mutton sheep are bred and bio-organic fertilizer is produced standardly on a large scale through the photovoltaic facility greenhouse; third, photovoltaic power generation is performed for self use, and excessive electricity is connected into the state grid; fourth, a beef cattle and mutton sheep traceable system is built, and foods are made safe and sanitary. Through the method, not only can solar resources be effectively utilized to output clean and green energy, but also efficient planting and breeding can be achieved, by-products are processed into organic fertilizer, and a new path is provided for green agricultural production. Because a full-frame high-standard support system is adopted for the photovoltaic agricultural greenhouse and photovoltaic modules are arranged on the greenhouse, the space of the greenhouse can be effectively utilized, power utilized in the greenhouse can be supplied through a photovoltaic power station, and equivalently, stereoscopic production is formed on the land with the same area.

The invention discloses a virtual synchronous generator-based photovoltaic power control strategy, which comprises a photovoltaic power generation system, an energy storage device and an inversion device, wherein a power supply output end of the photovoltaic power generation system is respectively connected with an energy storage end of the energy storage device and an inversion end of the inversion device; the output end of the inversion device is connected with a power grid; the inversion device carries out a power control through a virtual synchronous generator method; the output power of the inversion device is adjusted through the virtual synchronous generator method to reach a stable state; the output power is adjusted according to load fluctuation; stable frequency and voltage of the photovoltaic system can be maintained; and the grid-connected generation performance of a photovoltaic power station is effectively improved.

A photovoltaic power plant includes solar cells and inverters that convert direct current generated by the solar cells to alternating current. The reactive powers generated by the inverters are based on a reactive power generated by a virtual inverter. The virtual inverter has an equivalent impedance representing the impedances of the inverters in the photovoltaic power plant. The reactive power setpoints of the inverters may be received from a local interpreter. The local interpreter may generate the reactive power setpoints from a global reactive power setpoint generated by a grid controller.

The invention discloses a reactive voltage control method of a photovoltaic power station, which uses a photovoltatic power station synchronization point as a control target and reactive power as a regulating quantity. According to the reactive demand of the photovoltaic power station, a reactive power supply of the photovoltaic power station is integrally planed, the reactive output of each photovoltaic inverter and reactive compensating device in the photovoltaic power station is determined, and coordination control of the photovoltaic inverters and the reactive compensating devices in the photovoltaic power station is realized; and protection restraint conditions of the photovoltaic inverters and the reactive compensating devices are fully considered, and the photovoltaic inverters and the reactive compensating devices, which do not meet the restraint conditions, do not participate in the reactive voltage control. The control method provided by the invention can ensure that the reactive output of the photovoltaic power station synchronization point meets the system load change and inhibits the bus voltage fluctuation caused by load change, and has the function of maintaining the voltage of the photovoltaic power station synchronization point to be stable.

The invention provides a solar cell panel cleaning system in a photovoltaic power station. The solar cell panel cleaning system comprises an upper rail and a lower rail, idler wheels are mounted inside the rails, and the idler wheels are provided with a cleaning device support. Water spraying pipes are mounted on the two sides of the cleaning device support respectively, the water spraying pipes are connected with a water inlet pipe through a reversing valve, and a plurality of water spraying holes are formed in the water spraying pipes in the length direction of the water spraying pipes. The cleaning device support is provided with a hairbrush and a cleaning and water scraping rubber strip, and the hairbrush and the cleaning and water scraping rubber strip are placed between the water spraying pipes. An actuating device and a winding drum are mounted on the back face of a solar cell panel, and a wire cable on the winding drum is connected with the cleaning device support by being guided. One end of the upper rail is bent downwards in the vertical direction, one end of the lower rail is bent downwards in the vertical direction, so that the outer end parts of the rails and the main section parts of the rails are placed in different horizontal planes, the horizontal planes on the outer end parts of the rails are lower than the horizontal planes of the main section parts of the rails, and the inclined rail connection mode is adopted at the joints of the outer end parts of the rails and the main section parts of the rails. The solar cell panel cleaning system in the photovoltaic power station can overcome the defects in the prior art.

The invention discloses a physical modeling system with a wind power generation, photovoltaic power generation and energy storage integration system. The physical modeling system is based on power output characteristics of a wind power generation system, a photovoltaic power generation system and an energy storage system, and a converter system is utilized to simulate the wind power generation system, the photovoltaic power generation system and the energy storage system. The physical modeling system comprises an upper layer management module, a wind power generation simulation module, a photovoltaic power generation simulation module, an energy storage simulation module and a simulation power distribution network module. The wind power generation simulation module and the photovoltaic power generation simulation module can simulate power trends of a wind power field and a photovoltaic power station according to a set environment parameter. The energy storage simulation module employs a set of reversely connected current transformers to carry out simulation. Charge and discharge characteristics of a storage battery can be simulated, and an instruction of the upper layer management module can be received. According to a practical requirement, active and reactive power is sent or absorbed to stabilize voltage or frequency fluctuation of the power distribution network module. According to the invention, an inverter is utilized to establish a physical model, and a bottleneck problem that wind power, photovoltaic power and energy storage integration generation research can not be realized in a laboratory physical system is solved well.