216results about How to "Guarantee power quality" patented technology

The invention discloses a voltage source type direct-current deicing and static synchronous compensation device and a control method thereof. The voltage source type direct-current deicing and static synchronous compensation device comprises at least one basic current convertor unit. The basic current convertor unit comprises a connection electric reactor Ls, a modular multi-level current convertor MMC adopting a full-bridge sub-module, disconnecting links (K1, K2, K3 and K4), and smoothing electric reactors (Ld1 and Ld2). The voltage source type direct-current deicing and static reactive generation device can meet the requirements for deicing of power transmission lines of various voltage classes. The method for switching the voltage source type direct-current deicing and static synchronous compensation device among different function modes and the control method of the voltage source type direct-current deicing device can meet the requirement for safe and rapid deicing of the lines, no harmonic pollution at an access point is caused, and dynamic reactive power compensation can be provided for the access point. The voltage source type direct-current deicing and static synchronous compensation device can be used for a newly-constructed direct-current deicing project, can also be used for upgrading and reconstruction of the direct-current deicing device in the constructed direct-current deicing project, and has the wide application prospect.

The invention relates to a short-period electric generation power forecasting method applied to a photovoltaic electric generation system. The short-period electric generation power forecasting method is characterized by comprising two states that 1, the original electric generation power signals are subjected to empirical mode decomposition; and 2, a BP neural network forecasting model based on the genetic algorithm is built for each decomposition component. The short-period electric generation power forecasting method has the following major advantages that the accurate photovoltaic electric generation power forecasting is carried out in advance, the current flowing direction of the traditional electric grid and a photovoltaic electric generation microgrid is determined, a scheduling plan of an electric power system is made, and the operation cost of the electric power system is reduced; and meanwhile, the energy source storage plan can also be made in advance, the adverse influence on a large electric grid caused by intermittency and uncontrollability of the photovoltaic electric generation is reduced, and the market competitive advantage of the photovoltaic electric generation is enhanced. Meanwhile, the system also belongs to a precedent for applying the computer technologies such as the manual neural network and the genetic algorithm into the photovoltaic electric generation power forecasting, and higher novelty and practicability are realized.

A method and apparatus for locating and isoalting the failure in distributing circuit is disclosed. Said apparatus is used in conjunction with vacuum switch, power supply, and failure segment indicator to form a core unit of an automatic distributing network system. The said method can quickly locate and automatically isolate the failure region for increasing reliability of power supply by distribution system.

The invention discloses a mixed induction type active electric power filter system. The mixed induction type active electric power filter system comprises a rectifier transformer, a filtering branch, a rectifier and the other filtering branch, wherein the other filtering branch comprises three passive filters and a voltage source inverter, the passive filters are connected to the voltage source inverter, the primary side of the rectifier transformer is connected to a three-phase power grid through connecting impedor, an epitaxy winding of the secondary side of the rectifier transformer is connected with the rectifier, and the passive filters are connected to three junction points between a delta winding and the epitaxy winding of the secondary side of the rectifier transformer in parallel respectively. According to the mixed induction type active electric power filter system, influence of frequency fluctuation of the power grid side and the high-capacity nonlinear load side on electric power filtering performance is eliminated; meanwhile, the problems that serious harmonic pollution, high additional loss of a master device, high vibration and noise, low system power factor and low system operation efficiency are caused by harmonic waves and idle work to an industrial power distribution and consumption system are effectively solved on the premise that electric power quality on the power grid side meets the national standard of China.

The invention discloses a distributed photovoltaic monitoring system with power generation forecasting and a monitoring method. The distributed photovoltaic monitoring system comprises a work station, a data server, a collection server, an industrial personal computer, an interchanger and a man-machine operation interface, wherein the work station, the data server and the collection server are connected into a local area network of the system; the industrial personal computer is used for collecting the information of a distributed photovoltaic power station and uploading the information to the collection server; the collection server is used for uploading the information to the local area network; the work station is used for carrying out data analysis on the information; and the man-machine operation interface is used for displaying and giving an alarm. According to the distributed photovoltaic monitoring system, distributed photovoltaic operating data can be monitored in real time, the voltage and frequency of a distributed photovoltaic power generation system are stabilized on the basis of guaranteeing the quality of electric energy, optimal operation is realized, and the distributed photovoltaic utilization rate is improved.

A fault current limiter based on a fast switch and a triggered vacuum switch is disclosed, which comprises a fast switch (1) and a current limiting resistor (2) which are connected in parallel, wherein, a first pulse capacitor (3), a first inductor (4) and a first triggered vacuum switch (5) are connected in series between two ends of the fast switch (1); a second pulse capacitor (6), a second inductor (7) and a second triggered vacuum switch (8) are connected in series between two ends of the current limiting resistor (2). The invention: 1) enables short circuit current to be incapable of reaching a first current peak value in a state of infinite current; 2) causes arc current of the fast switch to achieve fast zero crossing and then arc blowout; 3) can pass through large pulse current at high triggering speed and can achieve arc blowout at the time of the zero crossing of the pulse current; 4) can rapidly inhibit the short circuit current; 5) and automatically limits current subsequent to the short circuit of a system to ensure quality of power supply and save establishment expenditure of network.

The invention provides an inverter parallel operation optimization control method. The method includes acquiring the rated capacity of each inverter in the parallel inverter system and the total load power factor angle of the parallel inverter system, determining the corresponding virtual impedance and sagging coefficient for each inverter according to the rated capacity and the total load power factor angle, determining the phase angle of each inverter based on the sagging coefficient, and then setting the same voltage amplitude for each inverter, determining the command voltage based on the voltage value, the virtual impedance, the phase angle, and the inverter output current, and controlling each inverter to output the active power and the reactive power according to the corresponding command voltage. The virtual impedance and sagging coefficient are determined by integrating the rated capacities of the inverters and the total load power factor angle of the parallel inverter system to realize the reasonable distribution of the active power and the reactive power of the inverters, the control effect of the inverters is optimized to reduce the voltage deviation, and the quality of the output energy of the inverters and the normal running of the user equipment or electric appliances are guaranteed.

The invention relates to a method for predicting the influence of disasters to a power system based on an improved AHP-anti-entropy weight, and belongs to the field of power transmission and distribution grids. To overcome the defect that the existing evaluation method is too subjective, further improvement is made in the invention. Thus, the method of the invention adapts to actual evaluation and horizontal comparison on influences of natural disasters to grids in various districts, can be adopted to analyze the advantages and disadvantages of development of the grids and find out the weak links of the grids, is a good guide to future grid planning and strong grid establishing, enhances the power supply reliability of the power system, especially the power supply reliability of the power system under the condition of disasters, and improves the investment income of the grids.

The invention discloses a low-voltage distribution line distribution transformer three-phase unbalance protection method and device. The method comprises following steps: monitoring a low-voltage distribution line, acquiring three-phase current of the low-voltage distribution line in real time, and obtaining actual power supply load; calculating distribution transformer load rate [beta] and neutral point current I0 on the basis of the actual power supply load and the three-phase current of the low-voltage distribution line; when the distribution transformer load rate [beta] and the neutral point current I0 satisfying a first judging condition, calculating three-phase unbalancedness of the low-voltage distribution line distribution transformer; selecting corresponding risk pre-warning levels for processing the low-voltage distribution line three-phase load on the basis of the three-phase unbalancedness. The device comprises a monitoring acquiring module, a first calculation module, a second calculation module, and an execution module. By means of the method and device, the unbalancedness of three-phase current can be greatly reduced.

The invention discloses an interconnection detection cloud platform facing electric vehicle charging facilities. The platform is used for a charging facility network access detection, engineering acceptance detection, a business expansion operation detection, a transportation and maintenance detection, compatibility and consistency tests of charging facilities and an electric vehicle and the like;the cloud platform is composed of a detection management center, a knowledge expert database, a data analysis center and a service data interface, and are used for providing support of a detection standard, equipment state analysis, fault analysis and the like for on-site detection personnel, and providing technical support for an industry management equipment platform account, an electric vehicle characteristic library, a charging equipment detection library, a charging equipment fault library, a detection method and the detection standard, and providing professional charging facility detection statistic analysis reports for the national power grid, the government, charging operators and suppliers, and providing a device fault detection report and a diagnosis report interface for the charging operators.

The invention relates to a method and a system for estimating the load model parameters of an electric system on line. When an on-load tap changer of a transformer in a substation is acted or a compensating capacitor in the substation is switched, a monitoring device at the feeder line outlet end of the substation or the junction of a power supply company and users records and analyzes system side disturbance caused by the process so as to estimate the load model parameters, wherein the estimation method comprises the following steps of: (1) detecting voltage disturbance generated by the system per se in real time by using the monitoring device; (2) after detecting the voltage disturbance, judging whether the disturbance is caused by acting the on-load tap changer or switching the compensating capacitor in the substation, if so, executing the step (3), and otherwise, returning to the step (1); (3) calculating relevant voltage and power changes and estimating load parameters according to the voltage and power changes; (4) saving the load parameters calculated on the basis of each-time disturbance in a database; and (5) carrying out regression analysis to mass of data saved in the database and then calculating the load parameters on different times in one day and one season.

The invention relates to a microgrid hybrid energy storage system and a control method thereof. The system comprises a power grid, wherein the power grid is connected with a microgrid common ac bus, the microgrid common ac bus is connected with a first subcircuit bus and a second subcircuit bus through microgrid energy management systems respectively, and the microgrid common ac bus is also connected with the first subcircuit bus through a transformer TM4; the microgrid common ac bus is also connected with the first subcircuit bus through a transformer TM5; the first subcircuit bus is connected with a lithium battery energy storage module, a super-capacitor energy storage module and a lead-acid cell energy storage module; the second subcircuit bus is connected with a load module. A microgrid internal energy storage system and loads are predicted, internal energy storage devices and loads are optimized and controlled during grid-connected operation, isolated network operation and state switching of a microgrid according to an energy storage power source and load characteristics, system output is smooth, and then intermittency and volatility of renewable energy sources are effectively inhibited.

The invention discloses a complex line full parallel AT traction power supply system and method based on comprehensive energy. The system comprises a complex line full parallel AT traction power supply system and a comprehensive energy system; a photovoltaic array, a wind generating set and a fuel cell are connected in parallel to a direct current bus, electric-hydrogen storage is added to supplement power vacancy and peak load shaving, comprehensive energy is accessed into a traction power supply system through a reasonable mode, the power and the state of each microsource are detected in real time, the energy optimization management by taking the lowest total generation cost as a target is achieved based on a particle swarm optimization. The complex line full parallel AT traction powersupply system and method based on comprehensive energy can ensure the safety and stability of the system and the high reliability of power supply; the traction energy consumption structure is optimized, and the new energy consumption level is improved; and the method meets the development direction of national energy conservation and emission reduction, and reduces the power supply requirement ofthe electrified railway on the power system to a certain extent.

The invention discloses a large-scale electric vehicle trunking system based on MMC and a control method thereof. The large-scale electric vehicle trunking system is characterized in that three phase elements composed of an electric reactor, an H-bridge module and a sub-module are connected to an alternating current power grid through an LC filter to form a topological structure of the large-scale electric vehicle trunking system based on MMC, virtual electrical charge states are calculated through the initial electrical charge state, user set standing time and expected electrical charge state of each electric vehicle, the sub-module of the electric vehicle corresponding to a driving signal generated by each carrier signal is determined according to the ranking of the virtual electrical charge states, the differentiation control for electric vehicle charging and discharging power connected to the sub-modules according to user requirements is realized, and the control for three-phase power balance and unit power factors on a power grid side is realized. The system is high in integration degree, high in modularization degree, high in efficiency, little in harmonic distortion, low in switching loss and high in fault-tolerant capacity, and independent control for the sub-modules in each-phase bridge arms can be realized.

The invention provides a micro-grid energy management method based on hybrid energy storage and electric automobiles and belongs to the field of power grid management. The micro-grid mentioned in theinvention is a distributive renewable energy source wind-PV(Photovoltaic)-ES(Energy Storage) grid-connected micro-grid. The micro-grid energy management method divides an energy management strategy into a peak-clipping valley-filling phase and a power fluctuation suppression phase. In the peak-clipping valley-filling phase, according to power generation predication and load predication technologyof distributive renewable energy sources such as wind power, photovoltaic power and the like, electric automobile slow charging periods are translated through a way of price support, and through combination with charging and discharging of an energy storage battery and power interaction between micro-grid connecting wires and external large power grids, peak-clipping valley-filling of power of theconnecting wires of the micro-grid is realized. In the power fluctuation suppression phase, considering the exertion fluctuation of wind power generation and photovoltaic power generation, and considering the large power and high stochastic behaviors of quick charging of the electric automobiles, a hybrid energy storage system is formed by a super capacitor and the energy storage battery for commonly suppression on power fluctuation of the connecting wires of the micro-grid. Finally, energy optimized control of the connecting wires of the micro-grid is realized.

The invention provides a power-voltage coordination control method and device for a DC power distribution network, and the method comprises the steps: building a long-time scale system optimization control model according to the network topology, power and load conditions of the DC power distribution network; solving the long-time scale system optimization control model, and calculating the flow distribution of the DC power distribution network and the power reference value and voltage reference value of a current converter station; determining a sagging control curve according to the power reference value and voltage reference value of the current converter station; and achieving the no-difference adjustment of voltage according to the sagging control curve during load disturbance. The device comprises a modeling unit, a solving unit, a sagging curve control unit, and an adjustment unit. According to the technical scheme of the invention, the method can improve the operation reliability of a power grid, and guarantees the electric energy of the DC power distribution cabinet.

The invention discloses a wind power generator optimizing control system and a wind power generator optimizing control method based on PI (Proportion Integral) regulation. A yaw system and a variable pitch control system of a wind power generator are combined, and a unified control method is adopted; when wind speed is relatively low, the yaw system automatically regulate the windward direction of the wind power generator, so that the wind power generator can obtain the maximum wind energy; and when the wind speed surpasses rated wind speed, the variable pitch control system starts up to regulate the pitch angles of fan blades, so that the wind power generator always runs at the maximum power.

The invention discloses an offline operation control method suitable for a user-side microgrid. Research is carried out on an offline operation mode in the microgrid, a microgrid coordination control strategy of a layered structure is employed, the layered structure comprises a local control layer and a centralized control layer, and the method is applied to coordination control between multiple power sources and loads under multiple operation conditions. According to the invention, under the condition that the quality of electric energy is guaranteed, by full use of the generating advantages of various micro power sources, the micro power sources of multiple types in the user side microgrid can be coordinated and controlled efficiently and reliably so that the requirements of the mcirogrid for energy balance and output are met. The method is simple and practical, the voltage and the frequency inside the microgrid are enabled to be stable, safe operation of important loads is guaranteed, at the same time, the output of a photovoltaic power generation system is fully utilized, and the utilization rate of regenerative energy is improved.

The invention discloses one triangle function limit micro variable flow method, which comprises the following steps: setting displacement transducer connection set to get needed basic voltage; using each base frequency and frequency function or different function to form triangle function limit micro variable equation with two sides as input and output signals; setting sine function transducer, power electron switch and outside circuit to get the analysis variable equation topological circuit and integrating the angle frequency and difference to form integral logic control.

The invention discloses a method for predicating the temperature of a photovoltaic cell through photo-thermal property coupling. The method includes the following steps that in combination with actual time and irradiance information provided by TMY data obtained through standard measurement, vertical equivalence is performed on incident light of the photovoltaic cell module, and based on an atmospheric dispersion longitudinal transmission model method, a vertical equivalence incident spectrum of a disperse wavelength is obtained; in combination with a crystal silicon layer texture structure and photo-thermal coupling properties of the anti-reflection process of an ARC layer, the wavelength dispersion absorption coefficient of each layer of the layered structure of the photovoltaic cell is calculated to obtained the flux of radiation absorbed by each layer of the structure; a layered structure energy balance equation of the photovoltaic cell is established, and a photovoltaic cell layered structure working temperature sequence corresponding to a time sequence is obtained through iterative calculation. On the basis of the existing function of predicating the output power of the photovoltaic cell, the function of predicating the working temperature of the photovoltaic cell module is further achieved, so that the precision of predicating the output power of the photovoltaic cell module is easily improved, and accordingly the output power of the photovoltaic cell module is accurately predicated.

The invention discloses a mechanical energy storage type highway speed bump power generation device comprising a mechanical transmission part and an energy storage power generation part. The mechanical transmission part mainly comprises a speed bump, a supporting frame, a metal strip, a first crank, a second crank and a driving swing rod, wherein the first crank, the second crank and the driving swing rod are sequentially hinged; one end of the first crank is hinged to the metal strip, the other end of the first crank and the second crank are jointly hinged to a sliding block, the sliding block is mounted in a guiding groove in a supporting plate, and a return spring is mounted on the lower portion of the sliding block in the guiding groove; a driving pawl of a ratchet wheel structure andthe driving swing rod are fixed, a rotating shaft is fixedly connected with a first one-way clutch and a second one-way clutch which are opposite in linkage direction, and the outer circle of the first one-way clutch is fixedly connected with a ratchet wheel; the energy storage power generation part comprises a power generator and a spring-type elastic energy storage device, a mounting gear is arranged on a power generator shaft, and the mounting gear is engaged with an external gear at the outer circle of the second one-way clutch. According to the mechanical energy storage type highway speedbump power generation device, the multistage variable speed is set, the high transmission ratio is achieved as much as possible through the smallest space, mounting is convenient, and the power generation amount is large.

The invention discloses a control method for frequency regulation of an electric power isolated network system. The control method is characterized by comprising the following steps of step 1, setting the permanent rotating-speed difference coefficient bp, PID parameters, frequency modulation dead zone 0.05Hz, and a frequency range from minus and plus 0.05Hz to minus and plus <theta>Hz for retrieving a frequency modulation module according to power grid requirements, wherein <theta> is a positive number greater than 0.05; step 2, detecting the current unit frequency by a speed regulator; step 3, obtaining a difference value <delta>f between the current unit frequency and a rated frequency 50Hz; and step 4, performing regulation according to the numerical value range of the frequency difference <delta>f. By adoption of the method, the problems of high frequency control error, low precision and instability of the electric power system, particularly the isolated network system can be solved; therefore, accurate and stable control of the power grid frequency is realized; the electric energy quality of the power system is ensured; power grid accident extension is prevented; and rapid recovery of the power grid in faults can be realized.

The invention discloses a power transmission network planning method and system based on line power flow distribution. The method comprises the steps of determining a power grid structure of a to-be-planned power transmission network; calculating the line power flow entropy of the power grid structure, wherein the line power flow entropy comprises a line load rate power flow entropy, a line activeloss rate power flow entropy and a line power transmission efficiency power flow entropy; calculating a balance degree factor of the to-be-planned power transmission network by adopting a mean squareerror method according to the line power flow entropy; establishing a multi-objective planning model according to the balance degree factor and the cost of the to-be-planned power transmission network, wherein the multi-objective planning model comprises an average line power flow balance objective function and a lowest cost objective function; solving the multi-target planning model by adoptinga multi-target bacterium drug-taxis algorithm to obtain an optimal solution, wherein the optimal solution is an optimal line planning result of the to-be-planned power transmission network. By adopting the method or the system, the power failure probability can be reduced, and the reliable and stable operation of a power grid is ensured.

The invention discloses an electric power quality treatment device which comprises a sampling module which is used for acquiring a voltage signal and a current signal; a first operational module which acquires harmonic current by means of the current signal; a second operational module which performs separation for obtaining each sequence component of unbalance current by means of the current signal; a third operational module which is used for calculating a reactive power shortage value by means of a voltage phase and a current phase; a control module which is used for obtaining a compensation solution and generating a control signal by means of the harmonic current and / or each sequence component and / or reactive power; and a power module which is used for compensating the voltage signal and / or the current signal by means of the control signal. Obviously, according to the electric power quality treatment device, the voltage signal and the current signal are analyzed through the operational modules for obtaining each analysis result; then a compensation solution is generated by the control module; and the power module finally finishes electric power quality treatment on a power grid by means of the compensation solution. The electric power quality treatment device realizes electric power quality treatment and saves investment cost of a user.

The invention relates to an intelligent grid technology and particularly relates to a micro grid energy management method. A micro grid comprises a plurality of distributed power generation units; each distributed power generation unit is provided with an intelligent agent; and communicated communication networks are designed among the distributed power generation unit and among the intelligent agents. The method comprises the following steps of: establishing an optimal mathematical model for micro grid distributed energy management; measuring and obtaining local information at grid connectionpoints where the distributed power generation units access to the micro grid, and carrying out initialization processing; implementing information exchange of the intelligent agent of each distributed power generation unit by the communication networks, calculating to obtain a reference value of active power outputs of the distributed power generation units, and according to the reference value,regulating the active power output of each distributed power generation unit; and determining an end condition. According to the method, various constraint conditions in the micro grid are comprehensively considered, a node does not need to be commanded to provide global load active demand information, fully distributed micro grid energy management can be implemented, and a calculation result is high in reliability and high in accuracy.

The invention discloses a grid-connected operation control method for a user side microgrid. On the basis of a layered-structure-based microgrid coordination control strategy, the layered structure includes a local control layer, a central control layer, and a distribution network scheduling layer. According to the invention, with study of a grid-connected operation mode in a microgrid, on the premise that the electric energy quality is guaranteed, the power generation advantages of all micro sources are fully utilized and coordinated control is carried out on various micro sources in a user side micrgrid efficiently and reliably, thereby meeting requirements of energy balancing and outputting of the microgrid. The method is suitable for coordinated control between multiple power sources, distribution networks, and loads on various operation working conditions. The method is simple and practical. The internal voltage and frequency of the microgrid become stable; the safety operation of the important load is guaranteed; and the impact on the large power grid is reduced. Meanwhile, the output of the photovoltaic power generation system can be fully utilized and the utilization rate of the renewable energy source is improved.

The invention provides a traction power supply information acquisition system based on synchronous measurement. According to the composition, power supply synchronous information acquisition units are arranged in a traction substation, an AT office and a partition office, and a power receiving synchronous information acquisition unit is arranged on a motor train unit. According to the composition of each power supply synchronous information acquisition unit, low voltage and a current transformer are respectively connected with a data acquisition card with a GPS module; the data acquisition card is connected with a data memory; and the low voltage and the current transformer are respectively connected with the voltage and current transformer output ends of the traction substation, the AT office or the partition office. According to the composition of the power receiving synchronous information acquisition unit, vehicle-mounted voltage and a current transformer are respectively connected with a data acquisition card with a GPS module; the data acquisition card is connected with a data memory; and the vehicle-mounted voltage and the current transformer are respectively connected with pantograph voltage and current transformer output ends. The system can collect the synchronous voltage and current information of all key nodes of a traction power supply system, and can establish an accurate locomotive circuit model based on the information.

The invention provides a full bridge uncontrolled rectifier fault diagnosis method based on insulation monitoring. Insulation resistance Rt of a system under normal operation conditions is measured first; the positive electrode and the negative electrode of an IMD injecting source based on a direct current injection method are connected with a neutral line and the ground respectively, and a system insulation monitoring value Rf when IMD forward injection is carried out is obtained through measurement; the direction of IMD injection signals is changed, the positive electrode and the negative electrode of the IMD injecting source are connected with the ground and the neutral line respectively, and the insulation monitoring value Rr when the IMD reverse injection is carried out can be measured; if the Rf or the Rr is not equal to the Rt, the system enters a fault diagnosis process, the real insulation resistance Rm of the system is calculated by using the collected Rf and the Rr, the Rm is then compared with the insulation resistance Rt under the normal operation conditions of the system, and whether the changing of the insulation resistance is caused by fault of a rectifier is obtained.

The invention relates to a ship shore-based variable frequency power supply system. The system comprises a main monitoring system, a shore-based power supply sub-system, a junction box sub-system, a cable winding cylinder sub-system and a ship power supply sub-system, wherein independent communication channels are arranged between the main monitoring system and the shore-based power supply sub-system and between the main monitoring system and the junction box sub-system, the cable winding cylinder sub-system and the ship power supply sub-system are connected with the main monitoring system, a main monitoring system controller coordinatively controls each sub-system, and the functions of operation mode switching, output power baking switching, grid-connected mode switching, load transferring, protection, metering, human-machine interaction and the like are achieved. By the shore-based variable frequency power supply system, different power baking outputs can be achieved, a shore-based power supply loop is configured for a plurality of berths, a path of high-voltage three-phase sine-wave power supply output can be provided, multiple paths of low-voltage three-phase sine-wave power supply outputs also can be provided, and the size of each path of output power can be flexibly configured.