192 results about "Power grid" patented technology

A wind power plant and a method of start up at least a part of a wind power plant connected to an external grid substantially without any energy delivered from the external grid for the start up is provided. The wind power plant having a plurality of wind turbines and at least one power source connected to at least one of the wind turbines in order to start the wind turbine while isolated from the remaining wind turbines. The started wind turbine may then supply power in order to start further wind turbines. Power may be delivered to the grid from the started wind turbines.

The present invention discloses an energy-feedback type power quality disturbance generating device, which relates to a power quality disturbance generating device. The device comprises a harmonic source (1), a feedback link (2), a middle direct current capacitor (3), a control terminal (4), a first LCL filtering link (5), and a second LCL filtering link (6). The control terminal (4) adopts a DSP controller to realize that a control signal which is generated according to the setting of a user controls the harmonic source to partially generate current disturbance. The harmonic source and the feedback link are cascaded via the middle direct current capacitor to form an AC-DC-AC topological structure so as to realize power feedback. The alternating current side of the harmonic source is connected with a power network via the first LCL filtering link. The alternating current side of the feedback link is connected with the power network via the second LCL filtering link. The device is capable of simulating harmonic current, active current, inductance reactive current or capacitive reactive current of a plurality of combination frequencies, and the device is capable of simulating various working conditions of a plurality of nonlinear loads such as electric arc furnaces, medium frequency furnaces, welding machines and frequency converters, etc.

The invention relates to a modeling method for a grid-connected photovoltaic power supply based on a PSASP (power system analysis software package). The method comprises the following steps of (1) firstly building a three-phase photovoltaic power supply simulation system and utilizing a conventional simulation verification method to perform simulation verification; (2) and then building a UD (user-defined) model of the photovoltaic power supply in the PSASP: a. establishing transfer functions for various parts of the photovoltaic power supply, drawing various functional block diagrams, establishing connecting relationships among the functional block diagrams and designating input and output relationships, i.e. the UD model of the photovoltaic power supply is established; b. balancing the initial value of the UD module; and c. solidifying the UD model in the PSASP. The modeling method provided by the invention has the advantages that the safe and stable running situation of the overall power grid after the grid-connected photovoltaic power supply is operated can be analyzed and researched in detail, thereby providing a predicable solution for the stability problem possibly produced after the photovoltaic power generation is connected in the grid, and improving the capability for switching the power grid in the photovoltaic power generation and the capability for stable running of the system after the power grid is switched-in.

The invention relates to the technical field of distribution network models, and provides a method and a system for establishing a distribution network model. The method comprises the following steps: acquiring preset maintenance authorizations of the distribution network model; establishing a primary equipment model and a secondary equipment model in a range specified by the maintenance authorizations, and drawing a figure, wherein the secondary equipment model and the figure are respectively associated with the primary equipment model; according to the primary equipment model, the secondary equipment model and the figure which are associated, generating a network topology model; and informing other model maintenance modules to update network topology models respectively maintained by themselves according to the generated network topology model by using online modeling information. According to the invention, through acquiring the preset maintenance authorizations of the distribution network model, the correctness of a multi-people maintenance model can be ensured, thereby facilitating maintenance; and other model maintenance modules are informed to update network topology models respectively maintained by themselves according to the generated network topology model by using online modeling information, so that a power grid model is always consistent with an actual power-grid running model.

The present invention is a protection system and protection method for a modular multi-level converter. The converter includes 3-phase 6 bridge arms, and the bridge arms include reactors and sub-modules. The present invention is between the reactor and the power grid. Optical current transformers are set between them, and whether there is an overcurrent phenomenon is determined through monitoring. If there is an overcurrent phenomenon, whether to perform temporary global blocking or permanent global blocking. The invention realizes temporary blocking protection of the bridge arm within 1.5ms after the overcurrent fault of the bridge arm occurs. The bridge arm sub-module can quickly avoid the damage caused by the overcurrent fault. The present invention also completes further system tripping and outage protection actions after the bridge arm overcurrent is temporarily blocked for 10 ms, thereby protecting the reliability and safety of the modularized multi-level in the flexible direct current transmission system.

The invention discloses a classified microgrid networking system based on terminal users and relates to the microgrid networking system. A user-stage microgrid is composed of a microgrid busbar, a distribution network busbar, a load switch, a power switch, an energy storage switch, a microgrid switch and a distribution network switch; the microgrid busbar is an alternating current or direct current busbar and is connected with a community-stage microgrid through the microgrid switch; the distribution network busbar is connected with a public distribution network through the distribution network switch; a conventional load is connected with the public distribution network; a compatible load is connected with the microgrid busbar or the distribution network busbar through the load switch; a distribution power supply is connected with the microgrid busbar through the power switch; and an energy storage device is connected with the microgrid busbar or the distribution network busbar through the energy storage switch. The classified microgrid networking system based on the terminal users is suitable for microgrid networking of terminal users who use photovoltaic or wind-solar hybrid equipment for distributed generation.

The invention relates to a smooth switching control method for an operating mode of a micro-grid inverter of different capacity micro sources. The method is applied to a micro-grid consisting of multiple different capacity micro sources. The method comprises the following steps: by virtue of switching among different switches, realizing smooth switching of an inverter control method under island/grid-connected operating modes, wherein the island operation is controlled by robust V-f based on capacitive equivalent output impedance so as to generate the voltage reference quantity, and the grid-connected operation is controlled by adopting PQ; adding a pre-synchronization link to be used for controlling the inverter output voltage to trace the power grid voltage when the inverter is switched from island operation to the grid-connected operation, and ensuring that the grid-connected operation is smoothly finished; introducing virtual impedance, designing the equivalent output impedance of the inverter to be capacitive, reducing loop current between parallel inverters, and well realizing power distribution among different capacity micro sources; and adopting double-loop control of the outer voltage loop and inner current loop, wherein the outer voltage loop is controlled by PI, and the inner current loop is controlled by dead beat. Therefore, the system is high in stability and high in dynamic response speed.

The invention discloses a cluster computing method for an online emergency control strategy for the transient safety stability of power system, belonging to the technical field of emergency control of the power system. Computing of the online emergency control strategy is divided into the stages that the emergency control strategy for transient power-angle stability is first computed; and based on searched optimization control strategy, voltage and frequency of the emergency control strategy for the transient safety stability are computed. According to the above technical scheme, the online emergency-control optimization strategy for the transient safety stability of a large power grid can be rapidly searched.

A microgrid photovoltaic power station generating capacity combined forecasting method belongs to the new energy power generation output forecasting field. The method comprises the following steps: 1) taking generating capacity data of a photovoltaic power station in a microgrid as input/output data of a forecasting model; 2) carrying out generating capacity forecasting through wavelet transform and a BP neural network; 3) carrying out generating capacity forecasting by utilizing a particle swarm algorithm to optimize a support vector machine; 4) obtaining model test weights by utilizing a variance-covariance combination method; and 5) calculating combined forecasting result according to the weights and model output corresponding to the new input. Compared with an existing forecasting method, the forecasting method starts from a new angle, avoids considering complex external factors and adopts a combination method, and has the advantages of being good in real-time performance, high in accuracy and high in adaptability and the like.

The present invention provides a method for determining arc discharge as well as failure of mechanical vibration and abnormal displacement in power equipment using acoustic energy feature. Here, acoustic energy feature is firstly introduced to realize real-time, online inspection of failure in power equipment, enabling qualitative determination of discharge as well as mechanical vibration and abnormal displacement, so as to improve early warning before damage. Two factors, in which one is early detection of discharge, and the other is early detection of mechanical vibration and abnormal displacement, are considered. When abnormality of any one of these factors is emerged, it is demonstrated that hidden trouble is presented. Here, acoustic energy feature is used to perform real-time, online monitoring. Due to reliable diagnosis and strong interference resistance provided by sound source signals, the operating condition in which the equipment is situated may be reflected clearly, avoiding damage to electric power grid.

The invention discloses a phase-change energy storage type radiant heating and cooling tail end device and a control method. The phase-change energy storage type radiant heating and cooling tail end device comprises a heating device, a cooling device, a control system of the heating device and a control system of the cooling device. The heating device is a phase-change energy storage type floor arranged on the ground, and the cooling device is a phase-change energy storage type suspended ceiling arranged at a roof. Phase-change materials and capillary networks are arranged in the phase-change energy storage type floor and the phase-change energy storage type suspended ceiling, so that the tail end of a radiant heating air conditioner is combined with the phase-change energy storage technology. By using the phase-change materials, energy storage at night and energy release in the daytime can be achieved so that operation cost can be saved for users using electric energy conversion, and the difference between the peak and the valley of a power grid can be reduced to protect power grid equipment; meanwhile, the method of combining time control with temperature control is adopted, the adopted temperature control can make up for defects of the time control, and therefore the indoor temperature is kept within the human comfort range.

The invention provides a charging system combining a power integrated body of the inner space of a vehicle and an outer charging suspension. The charging system aims at overcoming the defect that a few outer charging piles are available when existing electric vehicles have charging requirements. According to the design, a structure which combines the power integrated body used for charging the electric vehicle and installed in the vehicle, and the outer charging suspension outside the vehicle and is suitable for receiving a power source of the inner space of the vehicle is provided. The power integrated body installed in the inner space of the vehicle and composed of a charging pile, a suspension wire, a plug and an accessory is combined with a power supply device, namely a suspension wire and a conventional socket, on the outer charging suspension outside the vehicle through a power receiver, namely a suspension wire and a conventional plug, via a cantilever or a fixed suspension or a movable suspension or a multi-movable suspension in the inner space of the vehicle or above the occupation portion of the vehicle or above the height of the human body on the near side of the vehicle. The electric vehicle can be easily charged in a place with a civil power source, and in combination with a handheld device and the movable suspension which are carried in the vehicle, the limitation of the distance between a power grid power source and a parking place is overcome to the best.

The invention relates to a stand-alone renewable-energy generating device which generates electric energy from renewable energy sources, such as the sun or wind, in a stand-alone context, i.e. without being connected to a power grid. To allow users to asses their contribution to carbon dioxide emission savings, the invention provides a sensor element that is adapted to generate emission savings data representative of electric energy units generated by using a renewable energy device. Further, a clock device is comprised that is adapted to generate a time data representative of at least one of a time and a date specification and unique sensor-ID data are stored in a memory. A processor unit is adapted to time-stamp the emission savings data by combining it with the time data. The processor unit retrieves the sensor-ID data to combine them with the emission savings data to form savings profile data. A communication interface is adapted to communicate the savings profile data directly or indirectly via a network system. The sensor element may be provided integrated in a stand-alone renewable-energy generating device or in a separate emission savings sensor. The invention also relates to a method of maintaining user data associated with a savings profile data and sharing the savings profile data on the communications network. The sharing of these data aims to motivate further use of renewable energy devices.

The invention relates to a high-permeability wind power primary and secondary backup coordination control method, and belongs to the technical field of electric power system control. According to the method, the principle that primary backup is used at first and secondary backup serves as transition is used, and then primary frequency modulation backup capacity is supplemented so that the quick frequency modulation capacity can be abundant; the fluctuation window principle is used for calculating the secondary frequency modulation backup capacity of a power grid so as to realize coordinate control of the primary frequency modulation backup and the secondary frequency modulation backup and guarantee safe and stable running of the power grid. During running of a high-permeability wind power grid, through coordinate matching of the first frequency modulation backup and the secondary frequency modulation backup, wind power intermittent disturbance can be handled, and the system frequency can be stabilized; when the fluctuation window principle is used for conducting secondary backup distribution, it can be guaranteed that a power generating unit can complete a secondary frequency modulation task, meanwhile, the modulation times can be obviously reduced and the secondary backup efficiency can be improved.

A wind power station comprises a wind rotor; a transmission mechanically coupled to the wind rotor; an asynchronous generator having a generator rotor mechanically coupled to the transmission, and a generator stator electrically coupled to a power grid; and a protection unit protecting the generator and the transmission against accidental breakdowns of an alternating voltage provided by the power grid. The Protection unit includes at least one choke electrically arranged between the power grid and the generator stator, and a synchronous electrical machine electrically coupled to the choke.

The invention discloses an alternating current-direct current micro-grid system on the basis of an electricity energy collector. The alternating current-direct current micro-grid system comprises a power distribution network, a power distribution transformer, a distributed power source, distributed energy storage and loads which are sequentially connected with one another. The electricity energy collector is arranged among the loads, the distributed power source, the distributed energy storage and the transformer and is connected with an alternating-current 400V bus on a low-voltage side of the power distribution transformer by a point of common coupling (PCC) of a micro-grid. The alternating current-direct current micro-grid system has the advantages that the flexible all-controllable electricity energy collector is based on power electronic technologies, the micro-grid system on the basis of the power energy collector has electricity energy collector unified management and grid connection functions, direct-current and alternating-current circuits can be constructed in a unified manner, the quality of electric energy can be controlled in a unified manner, plug-and-play access of the distributed power source can be facilitated, and the alternating current-direct current micro-grid system brings convenience for unified coordination management and efficiency improvement.

Systems and methods for dynamic AC line voltage regulation are provided. A simple and cost-effective method for achieving AC line voltage regulation in AC systems including split-phase systems, of which the voltage for each voltage line may be regulated over a specified range, is provided. Buck and boost regulation is achieved for lowering or increasing the line voltage, respectively, with reference to the incoming grid voltage. Systems for dynamic AC line voltage regulation may comprise an AC/AC converter which uses fractionally rated switches and magnetics that handle only a fraction of the load current, resulting in lower costs. The use of an AC snubber further provides safe and robust switching of the main switching devices by eliminating failure prone switching sequences that are dependent on accurate assessment of voltage and/or current polarity for AC or bi-directional switches.

The invention discloses a harmonic reactive power compensation device as well as a control method thereof. The device comprises a bypass cabinet, an input transformer, a control device and a power cabinet, the input transformer adopts three-phase input, poly-phase winding output and the zigzag connection means, the power cabinet comprises 3N identical power units, input terminals of R, S and T at a rectifier side of each power unit are connected at output sides of the transformer, so each power unit has an independent direct current power supply, and the power units are mutually insulated and secondary windings of the transformer are also mutually insulated; wherein, N power units form one phase by means of cascade connection, all the power units are in star connection or in triangle connection with three phases correspondingly and then are connected with a power network by a reactor. The invention has advantages of high reliability, flexible control, realizable harmonic reactive power continuous compensation, fast response speed, high net side power factors and low total current harmonic wave.

The invention relates to a harmonic wave quantitative measurement method of a power system. For the current and voltage information of the power system, according to the time sequence and the synchronous equal-time-interval following harmonic wave three-dimensional direction, namely the harmonic wave amplitude and the dynamic variation features of the frequency along with the time, the amplitudes and frequencies of various orders of harmonic waves, the three-dimensional parameter and the three-dimensional curve of the time are obtained through measurement, the amplitude time curve and data of the various orders of three-dimensional following harmonic waves, the frequency time curve and data of the various orders of harmonic waves and the amplitude-versus-frequency curve and data of the various orders of harmonic waves are obtained through measurement, and the harmonic features and data of the power system are obtained through measurement in a quantitative mode. According to the harmonic wave quantitative measurement method of the power system, the harmonic wave impedance and harmonic resonance amplification feature of a power grid are accurately measured.

The invention relates to an electric vehicle charging station dispatching system and an ordered charging control method. On the basis of comprehensively considering the maximum charging power of ordered charging piles with adjustable charging power in a charging station and the target electricity utilization power issued by a superior scheduling system, the total target electricity utilization power issued by the superior dispatching system is distributed between the ordered charging piles, so that a value of the charging power of the ordered charging piles is between the minimum charging power and the maximum charging power, and the charging power of the charging piles in the charging station is comprehensively managed. Through the ordered charging control method, formulation of power sharing can be realized, so that transition of the charging behavior of the electric vehicles is guided from a one-way disordered random charging mode to an ordered charging mode, peak-sifting charging is achieved, power grid load fluctuations are reduced, energy losses of a power grid is reduced, and the reliability and economic benefits of a power distribution network are improved.

The invention relates to the technical field of testing and discloses a bidirectional charge-discharge motor controller testing system and method. The bidirectional charge-discharge motor controller testing system comprises a testing host computer, a simulator, and a bidirectional charge-discharge motor controller. The testing host computer is connected with the simulator and is used for transferring simulating models to the simulator, wherein the simulating models include a power grid model, a bidirectional charge-discharge motor model, and a battery module. The simulator is in communication connection with the bidirectional charge-discharge motor controller. The bidirectional charge-discharge motor controller, the power grid model, the bidirectional charge-discharge motor model, and the battery model form a closed-loop operation testing circuit. The simulator is used for acquiring the operation data of the bidirectional charge-discharge motor controller, sending the acquired operation data to the testing host computer, and sending simulating signals to the bidirectional charge-discharge motor controller. The invention further provides a bidirectional charge-discharge motor controller testing method. The bidirectional charge-discharge motor controller testing system and method may easily test the bidirectional charge-discharge motor controller, increase testing efficiency, and reduce testing cost.

The invention discloses a method for transforming a tangent tower of double-circuit double-bundle transmission lines by lifting in an electrified mode in another place, which belongs to the field of equipment installation. In the method, the current old tower and a common-tower double-circuit transmission lines thereon are involved. The method adopts a construction process of assembling a new tower in the electrified mode at a new tower position by using a landed derrick mast, transferring earth wires from the old tower to the new tower in the electrified state, and dismantling the old tower in the electrified mode in the longitudinal space between the common-tower double-circuit transmission lines, avoids the phenomenon that the two common-tower double-circuit lines have power failure atthe same time, improves the safety and the reliability of a power grid, overcomes the difficulty of an insufficient safe distance between a craning rope and electrified wires, and solves the problemsthat an cross arm member is overlarge, has the insufficient safe distance to the electrified wires, and is difficultly controlled by installation personnel. By slitting a tower body section member into 4 parts according to main materials and craning the 4 parts separately, the craning load of the derrick mast is lowered, and working safety is improved. The method can be widely applied to the fields of the displacement or transformation of the conventional overhead power transmission lines or iron towers.