91results about How to "Reduce active loss" patented technology

A flexible direct-current power-transmission converter-valve half-bridge structure power module test device comprises a primary loop and a secondary loop. The primary loop provides electrical connection for a converter-valve half-bridge structure power module test. The secondary loop is used for controlling the primary loop. The secondary loop and the primary loop are connected through a control monitoring plate card in a half-bridge structure power module in a flexible direct-current power-transmission converter valve. The primary loop comprises a company test side, a tested side and a load inductor. The company test side and the tested side are connected in series through the load inductor so as to form a closed loop. The company test side comprises one company test valve segment. The tested side comprises a plurality of tested valve segments. A structure of the company test valve segment and structures of the tested valve segments are the same and are formed through connecting half-bridge structure power modules with same quantities in series. The test device controls a module investment of the company test valve segment through a PWM modulation method. An initial value of a duty ratio of a control signal is 0 and then the value is increased slowly from a charging moment so as to limit an impact current during a charging process.

The invention relates to a power system reactive power optimization method giving consideration to off-limit voltage correcting and system active power loss reducing, and belongs to the technical field of power system optimized dispatching control. The reactive power optimization method is based on current power grid ground state flow and includes the steps of firstly scanning a whole grid to judge whether off-upper-limit voltage phenomena exist or not, and as for off-upper-limit voltage nodes, starting reactive power adjustment computing with voltage correcting as an object to eliminate the off-limit voltage; then starting voltage increasing reactive power optimization with system active power loss reducing as an object. The reactive power optimization method meets complexity operation requirements and the requirement, for the reasonable reactive power voltage automatic control computing result, of the power grid, and can be integrated in an automatic voltage control main station system operated in a dispatching center, and therefore the system can provide a control object for a reactive power voltage control strategy in real time through optimization computing according to the operation state of the power grid at present so that the control requirement for safe, high-quality and economical operation of the power grid can be met.

The invention relates to an integrated testing circuit for a modular multi-level converter valve and a control method of the integrated testing circuit. The integrated testing circuit comprises a main circuit, a test valve and a control protection circuit, wherein the control protection circuit controls the main circuit and the test valve and performs test valve charging and on-load tests. The normal operation of the converter valve is detected and guaranteed, and when the converter valve is subjected to misoperation, an error prompt is provided through a voltage signal. Voltage-regulating, alternating current and direct current testing circuits of the converter valve are effectively integrated, and testing voltage and current adjustable converter valve charging and on-load tests are finished. The operating states of components in a positive and reverse charging circuit of the converter valve are comprehensively checked through alternating current charging, and the safety and reliability of follow-up tests are ensured. Moreover, high current is generated by utilizing reactive energy exchange, and the active loss of the testing circuits and the capacity of a testing input power supply are reduced.

The invention relates to an AC-DC parallel power transmission channel power optimization distribution method and an AC-DC parallel power transmission channel power optimization distribution system. The method comprises, firstly, obtaining a total exchange power plan between various provincial networks and recent output plans of various generator sets, obtaining recent transmission power plans of DC interconnection lines of various provinces then according to a preset AC-DC parallel power transmission channel power optimization distribution model, and, finally, issuing the recent transmission power plans of the DC interconnection lines of the various provinces to corresponding convertor stations to be executed. Compared with the prior art, the method can effectively reduce active power loss of AC-DC parallel power transmission channels between the whole province network; and a transmission power safety constraint of sections of AC interconnection lines between the various provinces can also be accurately satisfied.

The invention relates to a reactive power compensation control method of three-phase unbalance system, comprises steps of: taking pressure or current of three-phase pressure or current to count reactive power Qa, Qb, Qc and active power Pa, Pb and Pc, respectively; setting and counting a Y compensatory part Qa, Qb, Qc required by a load Delta connection part and a Y compensatory part Qab, Qbc, Qca required by a load Y connection part and then obtaining a compensation formula; making three-phase power factor close to 1 and making three-phase reactive current balance to reduce usage quantity of capacitance, adjusting Q to make compensation effect and capacitance arrangement reach optimum; comparing and judging the reactive power of the three-phase unbalance system and counting scope, and compensating capacitance of the reactive power of the three-phase unbalance system. Using the system and the method provided by the invention, asymmetric loads are scattered into different outlet points to reduce out of limits of asymmetry caused by centralized connection.

The invention discloses an offshore wind turbine grid connection method. The method includes the steps that after an offshore wind turbine converts wind energy into alternating current, the alternating current is boosted to proper voltage through a boosting transformer and connected to an alternating current bus; the alternating current bus collects the alternating current boosted by the boosting transformer; an offshore convertor station converts the alternating current collected on the alternating current bus into direct current; a submarine cable transmits the direct current converted by the offshore convertor station in a long distance; a land convertor station converts the direct current transmitted through the submarine cable into alternating current; a main transformer converts the alternating current converted through the land convertor station into a proper voltage grade, and the alternating current is connected into a main power grid. The invention further discloses an offshore wind turbine grid connection system. The problems existing in grid connection of an offshore wind plant with the long distance and large capacity are solved.

The invention relates to an electronic device, in particular to an on-line dynamic harmonic treatment device which comprises a bus, a harmonic detection loop, a power supply transformation loop, an IGBT (Insulated Gate Bipolar Translator) inverter and a main loop. When current passes through the bus, the harmonic detection loop detects the power factor and the harmonic current of a power grid, and the IGBT inverter can generate a capacitive current having the same magnitude and a different direction compared with the current of the bus for the power grid to eliminate electronics. In the invention, the electronic detection loop only works when current passes through the bus, thus lagging conditions cannot occur, and the whole regulating speed is lower than 10ms.

The invention provides a multi-target voltage optimizing method of a wind power plant cluster. The wind power plant cluster is controlled as a whole, the minimum wind power plant grid-connection point voltage deviation, the minimum wind power plant cluster area transmission loss and the maximum wind power plant cluster voltage stabilization margin serve as the target functions, a wind power plant reactive power adjustable capacity constraint and wind power plant grid-connection point voltage upper and lower limit constraints are taken into account, the voltage optimized value of each wind power plant grid-connection point is obtained through optimizing calculation, and optimal control over the voltage of the wind power plant cluster is realized. The multi-target voltage optimizing method can be integrated in a wind power plant cluster control system and provides support for safe, stable and economical operation of the wind power plant cluster.

The invention discloses a reactive power optimization control method based on active power output of a photovoltaic power station, belonging to the technical field of photovoltaic power station operation control. The method of the invention comprises: the parameters of each photovoltaic inverter and SVG in the photovoltaic power station are obtained, The active power output P* of the photovoltaicpower station and the voltage control instruction of the grid connection point issued by the grid dispatching center (img file = 'DDA000179000293000011. TIF' wi= '126' he= '86'/) are calculated to obtain the reactive power compensation amount of the photovoltaic power station Q*; Calculate the reactive power capacity Qmax, Qmin of the photovoltaic power station; Taking the reactive power output ofPVGU and SVG as the control object, taking the minimum voltage deviation and the minimum active power loss of photovoltaic power station as the optimization objective, and transforming the fuzzy theory into a single objective optimization problem, the reactive power optimization control model based on the active power output of photovoltaic power station is established. Differential evolutionaryalgorithm is used to solve the model.

The present invention discloses a power grid energy conservation and loss reduction control method considering reactive response capability of a charging pile. the features of a charging pile taken as a reactive resource and the reactive voltage-regulation principle are analyzed, a reactive voltage optimization model considering the day-ahead optimal scheduling and the intra-day optimal correction is putted forward, according to the mathematic model, the day-ahead optimal scheduling employs a traditional parallel capacitor set and an on-load voltage regulation transformer to reduce transmission losses, and the reactive support of the electric car charging pile is employed to reduce the transmission losses when the intra-day abnormal operation; and a time-sequence progressive reactive control scheme based on the reactive voltage sensitivity is provided, and the reactive response capacity of the electric car is employed to perform reactive optimization correction. The power grid energy conservation and loss reduction control method considering the reactive response capability of the charging pile realizes the reactive local compensation and continuous regulation and reduces the active loss of the power grid.

The invention discloses an AVC control method and system based on coordinated control of a phase modifier and a capacitor bank, and a medium. The method comprises the following steps: if a control instruction is within a first specified threshold range, when a set of standby capacitors is brought into AVC coordinated control, the standby capacitors are switched off, and reactive power output is conducted on the control instruction through a phase modifier after power distribution; if the value of the control instruction is within a second specified threshold range, whether there is a set of standby capacitors brought into AVC coordinated control or not is detected; if there is no set of standby capacitors brought into AVC coordinated control, short-time reactive power output is conducted on the control instruction through the phase modifier after power distribution, a set of standby capacitors is switched in, and reactive power reserve of the phase modifier is released; and if there isa set of standby capacitors brought into AVC coordinated control, average output is performed by the phase modifier after the capacitor capacity is subtracted from the control instruction. Under thecondition that the change in available dynamic reactive power reserve of the phase modifier is small, the range of the control instruction can be increased and widened without greatly affecting the reactive group switching instruction of an original DC control and protection system. The method has the advantages of being good in compatibility and convenient for technical upgrade and reconstruction.

The invention discloses a reactive power coordinated control method for a wind power generator set and static var generator (SVG) equipment in a wind power plant. The reactive power coordinated control method comprises the steps of acquiring a target reactive power Delta Q of the wind power plant, controlling the SVG equipment to perform reactive power adjustment according to the target reactive power Delta Q until the reactive power of the wind power plant reaches the target reactive power Delta Q, and controlling a draught fan of the wind power generation set to substitute the SVG equipment to perform reactive power output or controlling the draught fan to increase the reactive power so as to substitute a part of the reactive power output of the SVG equipment. According to the reactive power coordinated control method, different adjustment amplitudes and adjustment speeds of the wind power generator set and an SVG are combined, the SVG is used for adjustment, the reactive power of the SVG is gradually substituted by the reactive power of the wind power generator set, so that the active power loss of the SVG is reduced, the dynamic reactive power storage of the SVG is maintained, and the internal power loss of the wind power plant is reduced on the condition that the voltage adjustment requirement is met.

The invention discloses a second-order cone operation control method for an alternating-current and direct-current power distribution network containing a power electronic transformer. The method comprises the steps that a PET-containing alternating-current and direct-current hybrid power distribution network multi-period operation control model is constructed; the injection power of different ports of the PET is controlled by utilizing the flexible regulation and control capability of the PET, so that the mutual coordination of the power between the different ports is realized, and the exchange requirement of power balance between an alternating current subnet and a direct current subnet is met; and second-order cone programming and linear approximation are adopted to carry out convex relaxation on the alternating-current and direct-current hybrid power distribution network multi-period operation control model, so that the solving efficiency of the multi-period operation control problem of the alternating-current and direct-current hybrid power distribution network containing PET can be improved. According to the invention, the system loss is effectively reduced, and the system operation economy is improved; and convex relaxation is carried out on an original nonlinear model through second-order cone relaxation and linear approximation, so that the PET-containing alternating-current and direct-current power distribution network second-order cone operation control model is provided, the accuracy is relatively good, and the solving efficiency is improved.

The invention relates to an electric vehicle orderly charging method based on an improved NSGA-II algorithm, wherein the method comprises the steps: taking each electric vehicle charging station as anode, building a power distribution network, taking the safe and stable operation of a power distribution network and the charging electric quantity of an electric vehicle as constraint conditions, and building a multi-objective optimization model with the minimum network loss of the power distribution network and the minimum charging cost of unit electric quantity; the electric vehicle dispatching center firstly acquires electric vehicle charging requirements of each charging station, basic loads of the charging stations and real-time electricity price data of each charging station; then an initial population is randomly generated by taking the total charging power of the electric vehicles in each time period as a variable, and the established multi-objective optimization model is solvedby adopting the improved NSGAII algorithm to obtain an orderly charging scheme of the electric vehicle. According to the method, a traditional genetic algorithm is improved, the convergence speed andconvergence precision of the algorithm are improved, and the charging cost of unit electric quantity can be effectively reduced; active loss of the power distribution network is reduced and power gridoperation efficiency is increased.

The invention discloses an intelligent temperature control heating system for a heating plate. The intelligent temperature control heating system is characterized in that a heating platform is divided into a plurality of small blocks which are singly heated through the corresponding heating blocks, a thermistor collects the temperature data of a heating region corresponding to each heating block in real time, a main controller controls the heating action of each heating block according to the temperature data, the temperature difference of each heating block is controlled in a reasonable range through balanced regulation, and the uniform surface temperature of the heating platform is realized. The intelligent temperature control heating system for the heating plate has the advantages that the heating area is extensible, the heating is uniform, the temperature difference of each unit area of the heating platform is controlled in a reasonable range, and the active loss is reduced.

The invention discloses an RC serial connection-based very fast transient overvoltage suppression method. A to-be-controlled circuit is subjected to simulation to determine circuit peak values in a transformer, an isolation switch and a bus when a circuit transformer end, an isolation switch end and a transformer side isolation switch end are connected with a series RC branch respectively; a suppression circuit connecting position is selected according to suppression requirement; and in the chosen position, simulation of the suppression effects of the RC series branch with different values is performed so as to determine the optimal suppression effect range to be used as the capacitance value and the resistance of the RC. By virtue of the suppression method, it is ensured that the peak value of the VFTO (very fast transient overvoltage) can be effectively lowered, and compared with the conventional parallel RC branch suppression method, the suppression method disclosed in the invention is lower in power consumption; and the effectiveness of the method is verified through simulation.

The invention discloses a single-phase grid-connected inverter system based on a double harmonic filter. The single-phase grid-connected inverter system solves the problems that the active loss is great and the promotion of high-frequency harmonic filter effect is not obvious existing in an existing grid-connected inverter filter system. The single-phase grid-connected inverter system comprises a direct-current power supply (1), a single-phase inverter (2), a double harmonic filter (4) and a single-phase alternating-current power grid (3), wherein the output end of the direct-current power supply (1) is connected with the input end of the single-phase inverter (2); the output end of the single-phase inverter (2) is connected with the single-phase alternating-current power grid (3) through the double harmonic filter (4); an inverter side inductor (Li) of the single-phase double harmonic filter (4) is connected with the output end of the single-phase inverter (2); a grid side inductor (Lg) of the single-phase double harmonic filter (4) is connected with the single-phase alternating-current power grid (3); and a first resonance circuit and a second resonance circuit are connected between the connection point of the inverter side inductor (Li) of the single-phase double harmonic filter (4) and the grid side inductor (Lg) of the single-phase double harmonic filter (4) and the ground in parallel. The harmonic pollution to the power grid when a distributed power supply is connected into the power grid is effectively reduced.