323results about How to "Improve voltage quality" patented technology

A distribution network automation system comprises a power distribution main station, power distribution substations and power distribution terminals. The power distribution main station is responsible for monitoring and managing global information and used for monitoring and acquiring data of a whole distribution network to complete fault handling within the whole network; the power distribution substations are used for managing distribution station terminal monitoring equipment such as switchgear cubicles for loop networks, switching stations for distribution networks and the like, acquiring, gathering and uploading signals of the power distribution terminals to the power distribution main station, and transmitting orders of the power distribution main station to the power distribution terminals; the power distribution terminals mainly used for acquiring data of primary equipment, controlling switchgears, detecting and recognizing faults and sending fault information to the power distribution substations and the power distribution main station. The distribution network automation system has the advantages that power supply reliability can be greatly improved, fault time can be greatly shortened, voltage quality can be greatly improved to provide optimal voltage for users, and labor intensity can be relieved for operators; management level of the whole power distribution system can be improved, working efficiency is improved, and user service level is improved.

The invention discloses a distributed type power supply zone branch circuit three-phase load current balance monitoring method and device and belongs to the field of power supply and distribution devices. At least one three-phase load current balance main controller is arranged, load current signals of each phase circuit in each branch loop are collected, according to the obtained load current signals of each phase circuit, the three-phase current unbalance rate or the mean value of the three-phase current unbalance rate of each branch loop is computed, and the unbalance situation of three-phase load current of each branch loop is judged. The magnitude of load current in each unit meter box of each branch loop is collected, and the phase of unit meter box load which needs to be adjusted is determined. According to the three-phase load current unbalance situation of a certain branch, a control instruction is issued to an automatic phase-changing switch in a unit meter box corresponding to the branch loop, converting of load phases is carried out, adjusting of three-phase load current balance of each branch loop on the low-voltage side of a distribution transformer is achieved, and the real balance of distribution transformer low-voltage side main loop three-phase load current is guaranteed.

The invention relates to an energy storage optimization and coordination control method for a direct-current micro grid group. When multiple sub micro grids are operated in parallel, an energy storage system in each sub micro grid automatically adjusts power distribution according to the maximum charging and discharging power and the state of charge (SOC) of the corresponding energy storage system, and therefore the safety of the energy storage systems is improved while distributed generated power fluctuation can be smoothed and the bus voltage quality can be improved; when the energy storage systems of all the sub micro grids cannot effectively buffer the system power supply and demand, an energy storage power station needs to be connected to control stabilization of the bus voltage. According to the energy storage optimization and coordination control method for the direct-current micro grid group, the virtual impedance of droop controllers of all energy storage units in the energy storage power station is adjusted by adopting fuzzy control to achieve automatic distribution of the power among the different energy storage units and SOC balance, fuzzy input is segmented, the SOC balancing speed of the fuzzy input in different ranges is increased by adopting fuzzy control, bus voltage drop caused by droop control is compensated by adopting a bus voltage feedback control method, and the bus voltage quality is improved.

A system is provided for mitigating an electric unbalance of a three-phase current at a Point of Common Coupling being located between a wind farm having a plurality of wind turbines and a power grid. The system includes a measurement device and a central wind farm controller. The measurement device measures the electric unbalance at the Point of Common Coupling and provides a measurement signal being indicative for the measured electric unbalance. The central wind farm controller is coupled to the measurement device and controls the operation of the plurality of wind turbines. In response to the measurement signal the central wind farm provides a control signal for mitigating the electric unbalance at the Point of Common Coupling. Also provided is a corresponding method for mitigating an electric unbalance of a three-phase current and a computer program for controlling and/or for carrying out the mentioned method.

The invention discloses a multi-converter parallel circulating current restraining method with quick and reactive support. For a single converter, drop control calculation is adopted, and an output reference voltage of the converter is synthesized; resistance-capacitance virtual complex impedance is guided in the output current feedback of the inverter, so that the equivalent output impedance of the converter is of resistance-capacitance performance, wherein capacity component realizes quick and reactive support of the inverter, the resonant vibration between the output impedance of the inverter and the impedance of an electrified wire fence is restricted through resistance component, and fundamental wave circulating currents and harmonic circulating currents are reduced; and through a voltage current control loop, the stability and control precision of a system are further strengthened, and accurate distribution of power is realized. According to the method, the problem that the existing method is not high in power equipartition precision, relatively large in circulating current and relatively large in voltage fluctuation, and the method can be applied to power generation parallel control systems of industrial special power supply and new power supply.

The invention relates to a power network model-based wind power field automatic voltage control method which comprises the following steps of: 1, reading original data and building a wind power field power network mathematical model; 2, reading a wind power field real-time running working condition and a voltage target value released by the power grid dispatching; 3, carrying out load flow calculation to obtain initial load flow distribution on the basis of the former two steps; 4, distributing and releasing the reactive power reference value of a wind driven generator according to a sensitivity ordering strategy; 5, distributing and issuing the reactive power reference value of a dynamic reactive compensation device according to the sequence; and 6, confirming and releasing the tapping point gear reference value of an on-load tap changing transformer according to a step-by step adjustment strategy. According to the power network model-based wind power field automatic voltage control method, the unified coordination control among the reactive power of the wind power field wind driven generator, the reactive power of the dynamic reactive compensation device and the tapping joint of the on load tap changing transformer can be realized.

The invention discloses a multi-agent self-adaptive drop consistency coordination control method and apparatus for a direct current microgrid. The method comprises: by applying a multi-agent consistency protocol into a direct current microgrid virtual navigator multi-agent structure, obtaining a direct current microgrid consistency protocol based on a virtual navigator agent neighbor set; obtaining a non-linear error consistency control protocol of a direct current microgrid system through the direct current microgrid consistency protocol based on the virtual navigator agent neighbor set; controlling the direct current microgrid system through the non-linear error consistency control protocol and a proportional complex integral to obtain self-adaptive dynamically changed virtual impedance and output voltage for controlling a DC-DC converter. The apparatus comprises a first obtaining module, a second obtaining module, a third obtaining module, an establishing module and a fourth obtaining module. According to the method and the apparatus, the virtual impedance of the direct current microgrid drop control can be dynamically adjusted in real time, the busbar voltage of the direct current microgrid can be kept to be close to a rated value, and the voltage quality of the direct current microgrid system is improved.

The present invention discloses a method of optimizing the static safe and stable operation limit of an electric power system. The method comprises the steps of using a BPA electric power system calculating and analyzing software to analyze an original data report containing the network structure and operation data of an evaluated electric power system; then carrying out the BPA power flow calculation on the data in the original data report; if the BPA power flow calculation is not convergent, correcting a control variable or a constrained condition until the BPA load flow calculation is convergent; then carrying out the N-1 power flow calculation; if the N-1 power flow calculation is not convergent, carrying out the N-1 optimal power flow calculation until the N-1 optimal power flow calculation is convergent, and outputting an N-1 power flow calculation report; and then using the data in the N-1 power flow calculation report to substitute for the data in the original data report, so that the situation that the evaluated electric power system is located in a power grid operation manner of the static safe and stable operation limit is guaranteed.

The invention discloses a multi-infeed extra-high voltage power grid transverter wattless configuration method based on a short-circuit ratio. The extra-high voltage power grid transverter wattless configuration method comprises steps of 1) determining an object grid structure to be analyzed and related parameters, 2) arranging operation modes of an electric power system, 3) selecting a specific operation mode to calculate system load flows under different DC control modes, 4) calculating a multi-infeed short circuit ratio according to a load flow calculation result, 5) calculating a multi-infeed DC node voltage comprehensive improvement index, 6) determining a candidate node of the multi-infeed extra-high voltage DC power grid transverter wattless configuration n according to the multi-infeed DC node comprehensive improvement index, and 7) programming a single objective function optimization program according to an objective function to determine a wattless compensation capacity. The extra-high voltage power grid transverter wattless configuration method guarantees to reduce the operation cost of the power grid, guarantee the power grid to safely, reliably, economically, and efficiently operate, has significance and provides technical basis to planning design and operation control of the mmulti-infeed high voltage DC power grid.

The invention discloses a distributed power quality conditioner and a method for controlling the same. The distributed power quality conditioner comprises one or more series compensation devices and parallel compensation devices, wherein each of the series compensation devices and the parallel compensation devices comprises a central controller; the series compensation devices and the parallel compensation devices do not share a direct current bus; and when the series compensation devices and the parallel compensation devices are used together, a management center is configured for acquiring the voltage of an electric network and load current information to determine the failure type of the electric network, and coordinately operating all series compensation devices and all parallel compensation devices.

The invention belongs to the power transmission and transformation equipment field and relates to an energy-saving box type outdoor substation. The substation comprises a top cover and a box body; the box body is divided into a high-voltage chamber, a transformer chamber and a low-voltage chamber. The energy-saving box type outdoor substation further comprise an intelligent controller; the intelligent controller is connected with a low-voltage chamber power transmission line through a power source input cable; the high-voltage chamber is provided with a high-voltage entering cabinet, a high-voltage metering cabinet, a high-voltage ring main unit and a high-voltage outgoing cabinet; the low-voltage chamber is provided with a low-voltage entering cabinet, a high-voltage reactive power automatic compensation capacitor cabinet and a low-voltage outgoing cabinet; and a transformer arranged in the transformer chamber is an on-load automatic capacitance adjustment power distribution transformer. The energy-saving box type outdoor substation is safe, reliable, energy-saving and efficient. With the energy-saving box type outdoor substation adopted, a power factor as well as the power supply efficiency and voltage quality of a system can be improved, and line loss can be decreased, and distribution line cost can be decreased, and electric energy can be saved, and the occupancy of a power grid and the no-load reactive loss and active loss of the transformer can be decreased, and capacity increasing cost and operation cost can be saved, and saving energy and consumption reduction can be realized, and great economic benefits and social benefits can be brought about.

The invention provides a reactive power control method of a grid gateway based on an automatic volume control (AVC) system. The reactive power control method comprises the following steps: obtaining the relation curve between the general active power delivered from an upstream gateway and the corresponding average coordinating power factor limit value according to the load flow calculation data and the restriction condition of a grid; monitoring the reactive power delivered from the pressure side in every transformer in an upper main network in real time, calculating the limit value of the upstream gateway coordinated power factor of every transformer substation according to the relation curve; calculating the limit value of the coordinated power factor of a downstream gateway according to the limit value of the upstream gateway coordinated power factor; updating a control parameter of the AVC system according to the limit value of the power factor of the grid downstream gateway, and regulating the reactive power of the grid gateway according to the control parameter. According to the technology provided in the invention, the safety running of the upper main network is fully considered, the reactive regulating ability and the active load level of a lower branch network are also considered; therefore the mismatch problem possibly caused by the reactive/voltage regulation of the upper and lower grids is solved, and the voltage quality of the grid is further improved.

The invention relates to a converter reactive power control method and system based on a virtual synchronous generator model, and belongs to the technical field of power grid control. The invention combines a power control technology based on a virtual synchronous generator and a current loop control technology based on a positive and negative sequence d-q dual-rotation coordinate system, and discloses a negative sequence reactive power control method under the condition that a power grid or a load is asymmetric. According to the converter reactive power control method and system based on the virtual synchronous generator model, power grid adaptability and operation stability of a converter are promoted, supporting on a grid connection point voltage is effectively assisted in, and quality of the grid connection point voltage is improved.

The invention discloses a new energy power supply system for an urban rail traction network and a control method. The system comprises an independent energy storage system located in a middle sectionof a line and a wind-photovoltaic-energy storage hybrid power generation system located at a car depot or a parking lot at an end of the line. The method comprises a step of obtaining a load predictedpower and an expected peak-valley value according to offline prediction data and historical data and judging whether there is a load based on urban rail running data, and a step of judging an operating condition based on a real-time voltage, comparing a predicted load power at a next moment and the expected peak-valley value and judging whether a state is a load running peak-valley state, and determining different control strategies through a judgment result to realize the effective control of an energy storage device in an independent energy storage system and a wind-photovoltaic-energy storage hybrid power generation device and an energy storage device in the wind-photovoltaic-energy storage hybrid power generation system. According to the invention, the consumption of renewable energysources such as local wind and light can be promoted, the grid pressure fluctuation is improved, the peak-load shifting is carried out for the load while the regenerative braking energy is effectivelyrecycled, the operating cost of urban rails is reduced, and the economic benefits are good.

The invention relates to a global reactive voltage optimization method for a power transmission and distribution network. The method includes the steps that coordinate boundary points of a power transmission network and an active power distribution network are selected; a power transmission network reactive voltage optimization model including complementary constraints is established, and an interior point method is used for solving; the optimization voltage of the power transmission network is converted into a three-phase voltage which is used as the three-phase voltage of an active power distribution network root node; a three-phase reactive voltage optimization model including complementary constraints of the active power distribution network is established, and the interior point method is used for solving; the three-phase optimization power of the active power distribution network is summated and then is used as the corresponding load power of the power transmission network; reactive voltage optimization of the power transmission network and reactive voltage optimization of the active power distribution network are in alternate iteration, when every two adjacent iteration changes of the boundary point power of the power transmission and distribution network meet convergence precision, the global reactive voltage of the power transmission and distribution network is subjected to optimizing convergence, and accordingly a global reactive voltage optimizing strategy is obtained. The problem that the reactive voltage optimization results of the power transmission and distribution network are inconsistent at the boundary points of the power transmission and distribution network can be solved, voltage and power mismatching at the boundary points is eliminated, and reactive resources of the two stages of networks are optimized.

The invention relates to an electric vehicle charging navigation method considering power grid information and charging station information. The power grid information and charging station informationare combined to dynamically adjust charging fee and charging station service fee, wherein the charging fee is calculated based on fluctuating electricity price, voltage quality is reflected with fluctuating charging price, the service fee is calculated with charging station occupation, and occupation degree of each charging station is reflected with fluctuating service fee. An electric vehicle ischarged with the charging station having low charging fee and service fee; the electric vehicle is therefore guided to the charging station with good voltage quality and low occupation for charging.In addition, navigation from a current position to the charging station is considered; the condition that the electric vehicle requires multiple charging during traveling is considered in combinationwith destination information, and therefore, a charging navigation strategy can be provided for a user based on overall optimal cost.

In a multilayer interconnection layer of a mother board and a memory module, a position relationship between a bus interconnection layer and a conductive layer of a power supply layer or a ground layer opposite to the bus interconnection layer is substantially held in not only the mother board but also the memory module and a relationship of multilayer interconnections is unified. As a result, it is possible to reduce disturbance of a return current of a high frequency signal given to the bus interconnection layer, to prevent degradation of quality of a signal waveform caused by the disturbance of the return current, and to prevent unnecessary electromagnetic waves from radiating caused by the disturbance of the return current. When a position relationship between the bus interconnection layer and an opposite conductive layer is not held at a constant, a similar effect is obtained by disposing a bypass capacitor in the vicinity of a portion where a plane of the bus interconnection layer and the conductive layer is switched.

The invention discloses a scattered type power quality regulation system. The scattered type power quality regulation system comprises one or more series-wound type compensation apparatus and shunt-wound type compensation apparatus, wherein each of the series-wound type compensation apparatuses and shunt-wound type compensation apparatuses comprises a central control unit; and direct current buses are not shared between the series-wound type compensation apparatuses and shunt-wound type compensation apparatuses. When the multiple series-wound type compensation apparatuses and shunt-wound type compensation apparatuses are jointly used, a management center is provided, wherein the management center judges power grid fault types by sampling power grid voltages and load current information so as to realize coordinated operation of the respective series-wound type compensation apparatuses and the shunt-wound type compensation apparatuses.

The invention relates to an overall salient type intermediate-frequency brushless excitation synchronous generator, which comprises a main generator, an exciter, an excitation regulating system. The excitation regulating system consists of a compound excitation device, a rotating rectifier and an AVR automatic voltage regulator, wherein the compound excitation device consists of a compound excitation winding, a compound excitation current transformer and a three-phase rectifier bridge, the stator of the main generator adopts a fractional slot type short-range winding, the slot number per pole and per phase q is a fractional value, the rotor of the main generator is formed by lamination of multi-pole rotor core laminated pieces, the rotor core of the main generator is of an overall salient type rotor core structure and is formed by overall punching and lamination of rotor core laminated pieces, each rotor core laminated piece is formed with a magnetic pole and a magnetic yoke integrated, and an axial air-cooling hole is arranged at the magnetic yoke. The generator realizes the brushless excitation intermediate-frequency generation, outputs the single-phase or three-phase intermediate-frequency voltage, and has the advantages of excellent performance, stable and reliable operation and high output power.

A four-bridge arm thyristor switch voltage-regulating circuit and voltage-regulating method. The voltage-regulating circuit includes a series transformer, an adjusting transformer, a four-bridge arm thyristor switch and a control circuit, the adjusting transformer is formed by four independent windings, including a 100V winding, a 300V winding and a 200V winding, wherein the 300V winding is located between the 100V winding and the 200V winding, output voltage of all levels is provided through combination, the four-bridge arm thyristor switch includes eight thyristor switches, a four-bridge arm type switching circuit is formed, each bridge arm is provided with two thyristor switches at upper and lower sides, and a control circuit controls switching-on and switching-off states of each thyristor, thereby realizing voltage regulation. The voltage-regulating circuit and the voltage-regulating method in the invention can provide voltage regulation with a measuring range of +/-600V and a precision of 100V, and of 13 levels in total, and has the characteristics of large voltage regulation measuring range, high precision, fast switching speed, low production cost, long service life and the like.

The invention provides an energy storage system collocation method, which comprises the steps: obtaining target data; utilizing a mixed integral linear programming method and a particle swarm optimization to respectively calculate an energy storage system scheduling objective function and an energy storage system optimizing objective function; utilizing an energy storage system optimizing collocation result to collocate an energy storage system, wherein the building processes of the energy storage system scheduling objective function and the energy storage system optimizing objective function comprise the steps: a distributed generation mathematic model in a virtual power plant is built; a sub-objective function is analyzed and built according to the mathematic model and the effect of the energy storage system in the virtual power plant and comprises an economy sub-objective function, a network supply sub-objective function and a voltage sub-objective function; the energy storage system scheduling objective function and the energy storage system optimizing objective function are respectively built according to the sub-objective functions. According to an optimizing collocation result solved by an energy storage system optimizing collocation model, the energy storage system of each collocation can be in an optimal scheduling state during operation and work.