69results about "Single network parallel feeding arrangements" 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 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 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 provides a pilot node selecting method based on wind electric power fluctuation probability characters. Due to the fact that large-scale renewable energy resources are merged into a control area, Fluctuations and trends of currents are changed greatly, and many challenges are brought to area voltage reactive power control. Pilot nods are as primary goals of secondary voltages, when the pilot nods are selected, access of renewable energy resources needed to be considered. According to the pilot node selecting method based on the wind electric power fluctuation probability characters, access of wind power is as an example, statistics of power injection probability distribution characters of a wind power plant in different periods is carried out, various system random working states with different probabilities are formed through superposition of the power injection probability distribution characters and load working modes of peaks, waists and valleys of a system, selected pilot nodes satisfy that after the system is subject to random disturbance, voltage deviation expectation of the rest load nodes in the whole net is made to be minimum under various random working states through control and elimination of voltage deviations of the selected pilot nodes. Feasibility and validity of the pilot node selecting method based on the wind electric power fluctuation probability characters are verified by IEEE three-machine-nine-node system simulation results and New England 39-node system simulation results.

A programmable uninterruptible power supply for coupling battery powered systems associated with a mobile site, such as a vehicle, to the primary electrical system of the mobile site operates to selectively couple the battery powered systems to the electrical system of the mobile site and to a secondary, or back-up battery separate from the primary battery associated with the electrical system of the mobile site. Various system control functions are performed, including reverse battery protection, over voltage and under voltage protection, battery drain protection, battery charging detection, reverse current detection and uninterruptible power switching. For detected adverse operating conditions, the load is disconnected from the electrical system of the mobile site and the back-up battery is used to operate the battery powered systems which are to be protected from such adverse operating conditions.

The purpose of the present invention is to provide a method and device for operating a power system, and a rechargeable-battery management device, that extract maximum performance from rechargeable batteries and use said batteries evenly while taking into consideration cost and the operation of the batteries. In order to solve said problem, in this method for operating a power system provided with a plurality of rechargeable-battery devices and a plurality of electric generators, the amount of power that a rechargeable battery available during a scheduled time period on a scheduled date will be able to supply is determined, an economic-dispatch calculation including the determined amount of power that the aforementioned rechargeable battery will be able to supply is performed for the power system, and said rechargeable battery is used to supply power during the scheduled time period on the scheduled date.

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.

The invention relates to an energy internet oriented AC/DC hybrid microgrid coordination optimization control method and system, and belongs to the technical field of the energy internet and microgrids. The system comprises a plurality of sub microgrids, each sub microgrid consists of two interface converters which are connected with an alternating current bus and a direct current bus, the first interface converter adopts a current control closed loop, the second interface converter adopts a voltage control closed loop based on self-adaptive virtual impedance, and the power deviation of the two interface converters is used as an adaptive setting reference of the virtual impedance of the second interface converter. The first interface converter adopts the strategy of combining the power outer loop control and current outer loop control strategy and the current inner loop control strategy, the second interface converter adopts the strategy of combining the droop control outer loop and the voltage control strategy based on the self-adaptive virtual impedance and the current inner loop control strategy, by coordinated control of the adaptive virtual impedance, the performance of the AC/DC hybrid microgrid is improved.

The invention relates to a regional multi-microgrid dynamic networking method based on a graph theory. The regional multi-microgrid dynamic networking method is technically characterized by comprisingthe following steps that 1, according to a multi-objective function optimum in global economic operation and highest in system power supply reliability of an intra-regional multi-microgrid and presetconstraint conditions, an optimization model of a regional multi-microgrid is established; 2, a regional multi-microgrid dynamic networking model based on the graph theory is established by combiningwith network topology connection of a regional multi-microgrid system based on the regional multi-microgrid optimization model established in the step 1; 3, an improved particle swarm algorithm is adopted to solve the regional multi-microgrid dynamic networking model based on the graph theory, and dynamic networking of the regional multi-microgrid is achieved. By combining with interconnection and intercommunication characteristics of the regional multi-microgrid and power output constraint of the microgrid, the optimization model optimum in global economic operation and highest in system power supply reliability of the regional multi-microgrid is established, and a solution is provided for dynamic multi-microgrid networking in a regional range.

The invention provides a fuzzy control method for wind power generation grid-connected running. The fuzzy control method comprises the following steps of firstly, building a wind power generation experiment system, wherein the wind power generation experiment system comprises two groups of wind power generators, two groups of AC/DC rectifiers, two groups of DC/DC converters and a public load, and the two groups of wind power generation devices are used for jointly providing electric energy for the load to use; secondly, building a mathematical model of the wind power generation experiment system according to a physical principle, wherein the mathematical model belongs to an interconnection system with two non-linear sub-systems; and finally, designing a distributed state feedback fuzzy controller based on the mathematical model, and giving out a simulation test platform of the system. With the distributed fuzzy control method provided by the invention, safe and stable running of a wind power generation network can be ensured.

The invention relates to wind and light storage micro-grid system for an industrial park. The main technical characteristics lie in that the wind and light storage micro-grid system includes a wind and light generation device, a generation system measurement and control terminal, a storage unit, an invertion device and a far end control master station, wherein the input end of the wind and light generation device is connected with a wind energy device and a solar energy device; the wind and light generation device is connected with a generation system measurement and control device; the storage unit is connected with the invertion device; the output end of the wind and light generation device and the output end of the invertion device are switched in the grid or are connected to a load for supplying electricity for the load; the generation system measurement and control terminal is connected with the invertion device; the generation system measurement and control device is connected with the far end control master station. The wind and light storage micro-grid system effectively integrates the functions of wind generation, photovoltaic generation, energy storage, off-grid inversion, grid-connected feed and the like, realizes the multifunctional conversion of electrical energy, and has the characteristics of energy saving, environmental protection, low cost, high efficiency, stable performance, and the like.

The invention discloses a transient stability analysis method for a power system containing VSG-IIDG based on an energy function. The transient stability analysis method comprises the steps of: fitting virtual power angle characteristic curves of an inverter in different operating states, so that output electromagnetic power and virtual power angles of the inverter are represented by means of a unified model on the premise of not changing the virtual power angle characteristics, and the inverter performs power output according to the fitted virtual power angle characteristic curve; and finally, determining whether the system is stable correctly since the system energy function constructed according to electromagnetic power after fitting calculation strictly conforms to the Lyapunov condition. The constructed system energy function has negative definiteness and can determine whether the system is stable correctly, and is of great significance to analyze the transient stability of the system containing the VSG strategy inverter.

A method includes selecting a first desired parameter of a machinery configured to produce power, a first surrogate parameter related to the desired parameter, and a first model configured to generate the desired parameter based on a first relationship between the first surrogate parameter and the first desired parameter. The method also includes receiving data related to the first surrogate parameter from a plurality of sensors coupled to the machinery and generating the first desired parameter using the data and the first model. Further, the method includes deriving a first set of empirical data relating the first surrogate parameter to the desired parameter and adjusting the first model based on the data, the first surrogate parameter, and the first set of empirical data, wherein the adjustment to the first model occurs in real-time.

The invention provides an energy storage optimal configuration method and system. The energy storage optimal configuration method comprises the following steps: determining the discharge price of an energy storage power station during peak period, determining the charging price of the energy storage power station during valley period and determining the compensation price of auxiliary services forthe energy storage power station participating in peak shaving; determining the maximum net income of the energy storage power station based on the discharge price of the energy storage power stationduring the peak period, the charging price of the energy storage power station during the valley period and the auxiliary service compensation price of the energy storage power station participatingin peak shaving; and determining the capacity allocation of the energy storage power station based on the maximum net income and constraint conditions of the energy storage power station. According tothe energy storage optimal configuration method and system, electronic equipment and the storage medium, the energy storage power station is optimally configured based on the price mechanism so thatthe optimal capacity configuration of the energy storage power station can be determined, the income of the energy storage power station can be maximized and the large-scale application of the energystorage power station can be facilitated.

The invention discloses a power grid optimization partitioning method for new energy consumption analysis. The method comprises the following steps: S1, determining a unit sub-region power grid Ui; S2, collecting and making statistics of a new energy historical generated output data sequence and eliminating abnormal data Pre, i(t); S3, calculating accumulated generating capacity Ere, i of all newenergy power stations; S4, collecting historical power load data exceeding Pload, i(t) and removing the abnormal data; S5, calculating accumulated power consumption Eload, i of the power load; S6, calculating matched power generation power Pmatchre, i (t) and matched power utilization power Pmatchload, i(t) at each moment; S7, calculating the total match power generation electric quantity Ematchre,i and the total match power utilization quantity Ematchl, i; S8, calculating a time sequence match degree Kmatch, i; and S9, classifying source-load match degree coefficients Kmatch, i of all unit sub-regions. The optimization method, through long-time statistical data analysis, adopts a key characteristic index of the time sequence match degree to measure the match degree of the generated outputand the power load of the photovoltaic power station on the time sequence, and provides a basic support for formulating planning schemes of site selection and constant volume and the like of distributed photovoltaics.

The invention relates to the technical field of power market, in particular to an estimation method for capability of accepting a renewable energy source in a middle period of a power grid. Factors affecting the capability of accepting the renewable energy source in the middle period of the power grid comprise system average economic peak regulation capability, system average peak regulation demand and power grid external transmission passage, an index for estimating the capability of accepting the renewable energy source in the middle period of the power grid is system average peak regulation adequacy, and the capability of accepting the renewable energy source in the middle period of the power grid is estimated by solving the system average peak regulation adequacy. A special estimation method for the capability of accepting the renewable energy source in the middle period of the power grid is given out by the invention, and the estimation method has the advantages of comprehensive consideration and high applicability, and is simple and convenient to operate.

The invention discloses a DFIG impedance remodeling control method and a DFIG impedance remodeling control system without phase-locked loop direct power control. The impedance remodeling control method comprises the following steps: analyzing DFIG impedance high-frequency capacitance characteristics of phase-locked loop-free direct power control according to an equivalent single-input single-output impedance Bode diagram; according to DFIG impedance high-frequency capacitance characteristics of phase-locked-loop-free direct power control, analyzing the generation reason and parameter sensitivity of high-frequency resonance through a DFIG high-frequency simplified model; according to the relationship between the frequency coupling characteristic intensity and the DFIG phase margin of the phase-locked loop-free direct power control, introducing voltage feedforward virtual impedance to carry out DFIG impedance remodeling, and carrying out parameter design; according to the equivalent single-input single-output impedance Bode diagram, analyzing the DFIG phase margin and the remodeling effect after the voltage feed-forward virtual impedance is added. According to the invention, the frequency coupling characteristic of the DFIG system is reduced, the phase margin of the DFIG under the inductive weak power grid is improved, and the high-frequency resonance is inhibited.

The invention discloses an energy storage type electric energy quality regulator for a wind power generation system. The energy storage type electric energy quality regulator comprises a three-phase full-bridge DC-AC converter, a three-phase half-bridge DC-AC converter, a two-way DC-DC converter and an energy storage device. One outgoing line terminal of an alternating current port of each phase of the three-phase full-bridge DC-AC converter is connected with an outgoing line terminal of the corresponding phase in a wind power generation set, and the other outgoing line terminal is connected with a connecting terminal of the corresponding phase in the low-voltage side of a boosting transformer. Direct current ports of all phases of the three-phase full-bridge DC-AC converter are connected with a direct current port of the three-phase half-bridge DC-AC converter, and three alternating current ports of the three-phase half-bridge DC-AC converter are connected with a connecting port in the low-voltage side of the boosting transformer. The energy storage device is connected with the alternating current ports of the three-phase half-bridge DC-AC converter through the two-way DC-DC converter. The energy storage type electric energy quality regulator can smooth the power fluctuation of wind power and improve the low voltage ride-through capacity of the wind power.

The invention discloses a series power supply circuit voltage regulation method based on photovoltaic inverter phase modulation. The series power supply circuit is subjected to voltage regulation based on the phase modulation operating capability of the photovoltaic inverter; common Q(U) and cos<phi> (P) control strategies are improved, so that reactive support can be provided for a power grid at any time while investment of dynamic reactive compensation equipment can be reduced for a photovoltaic power station; and by calling all photovoltaic inverters to be participated in power grid voltage adjustment, the minimum of reactive absorption total quantity, and lowest power grid active and reactive loss can be realized.

The invention discloses a cascade hydropower station optimal scheduling system and method, and a safety power grid system, and the method comprises the steps: carrying out the preliminary calculationof each power station of a cascade power station group through the predicted storage flow condition and planned output of each power station of the cascade power station group, and obtaining the stateof the cascade power station group; traversing the state sequence of each power station of the cascade power station group according to the time sequence, if the state of the current time period of the cascade power station group meets the set requirement, completing the calculation of the scheduling time period, and if not, performing water abandoning risk assessment according to the length of the pre-abandoning time, and performing output adjustment on the current time period. Through the scheme provided by the invention, each cascade power station is balanced in water abandoning risk underthe condition of meeting cascade overall operation optimization in the whole dispatching process, water abandoning is relatively reasonable, cascade water and electricity operation is optimized, andcascade water energy resources are fully utilized.