956 results about "Reactive power control" patented technology

A system and method of reactive power regulation in a wind farm having a plurality of wind turbines that provides optimum control of the reactive power compensation in the wind farm and is able to keep a reactive power reserve in order to support eventual grid contingencies.

Real and reactive power control for wind turbine generator systems. The technique described herein provides the potential to utilize the total capacity of a wind turbine generator system (e.g., a wind farm) to provide dynamic VAR (reactive power support). The VAR support provided by individual wind turbine generators in a system can be dynamically varied to suit application parameters.

Systems and methods for supplying power (both active and reactive) at a medium voltage from a DCSTATCOM to an IT load without using a transformer are disclosed. The DCSTATCOM includes an energy storage device, a two-stage DC-DC converter, and a multi-level inverter, each of which are electrically coupled to a common negative bus. The DC-DC converter may include two stages in a bidirectional configuration. One stage of the DC-DC converter uses a flying capacitor topology. The voltages across the capacitors of the flying capacitor topology are balanced and switching losses are minimized by fixed duty cycle operation. The DC-DC converter generates a high DC voltage from a low or high voltage energy storage device such as batteries and / or ultra-capacitors. The multi-level, neutral point, diode-clamped inverter converts the high DC voltage into a medium AC voltage using a space vector pulse width modulation (SVPWM) technique.

A reactive power controller for controlling reactive power in a wind farm grid connected to a utility grid and including at least two sub-grids and a collector portion is provided. At least one wind turbine is connected to each sub-grid, wherein the at least two sub-grids are connected to the collector portion and wherein the collector portion establishes the connection to the utility grid. The reactive power controller includes a device for determining an actual reactive power value at the collector portion, and a wind farm controller operatively connected to the device for controlling at least one of said wind turbines on basis of the determined actual reactive power value such that a desired reactive power value is attained.

The present invention provides a mixed integer cone programming based intelligent distribution system synthetic voltage reactive power optimization method. The method comprises: inputting a distribution system structure and a parameter of a distribution system; establishing a time sequence optimization model of a distribution system synthetic voltage reactive power control problem considering various types of adjustment means; converting the established model into a mixed integer second-order cone model; solving the obtained mixed integer second-order cone model by using a mathematical solver capable of solving mixed integer second-order cone programming; and outputting a solution result. The method provided by the present invention greatly reduces solving difficulty and facilitates performing solution by using a solving tool, so that a complex mixed integer non-linear programming problem can be solved, cumbersome iteration and a large number of tests are avoided, and the calculation speed is greatly improved.

Systems and methods are provided for reactive power regulation and voltage support for renewable energy plants. In one embodiment, a system and method are provided for coordinating voltage and reactive power output of a plant with one or more requirements associated with a utility. The method can include generating a VAR regulator output signal based at least in part on a reactive power control signal received from a utility, controlling reactive power and voltage output of the one or more power sources based at least in part on the generated VAR regulator output signal, aggregating reactive power output or the one or more power sources, and providing the aggregated reactive power to the utility.

Systems and methods are disclosed to control voltage profiles of a power grid by forming an autonomous voltage control model with one or more neural networks as Deep Reinforcement Learning (DRL) agents; training the DRL agents to provide data-driven, real-time and autonomous grid control strategies; and coordinating and optimizing reactive power controllers to regulate voltage profiles in the power grid with a Markov decision process (MDP) operating with reinforcement learning to control problems in dynamic and stochastic environments.

The invention discloses a wind power station reactive power control method and a system. The wind power station high voltage side bus voltage is used as a control target, the reactive power is used as the regulating quantity, the wind power station voltage control strategy and the power factor control strategy are selected or the system reactive power output is forcibly controlled to be a constant value according to the wind power station voltage fluctuation range and the power factors, and in addition, the reactive power output values of each fan and integrated reactive compensation equipment in the wind power station are determined according to the reactive power reference values required to be output by the wind power station. When the technology of the invention is adopted, the reactive power output of the wind power station networking points meets the system requirements for inhibiting the bus voltage fluctuation and regulating the wind power station power factor, and in addition, the reactive power output of each wind power generator set and integrated reactive compensation equipment in the wind power station can be controlled in a harmonious way.

A power inverter includes a regulator circuit that controls real and reactive power output by the inverter. The regulator measures real and reactive output power by calculating x-phasor components of the inverter's voltage and current output waveforms. Phasor calculation can be adapted for one or more pairs of single-phase voltages and currents. Determining the fundamental in-phase and quadrature components of output voltage and current reduces computational complexity by permitting the regulator to perform its power control processing largely in a dc signal domain, and enables separate real and reactive power control. The power inverter can include islanding detection logic, which exploits the ability to separately control reactive power. Exemplary islanding detection logic is based on determining whether changing the amount of reactive power output by the inverter induces an output frequency shift.

The invention discloses a novel electric power electric transformer. The electric power electric transformer consists of a high-voltage level, an isolation level and a low-voltage level, wherein the high-voltage level comprises 2*N*n half-bridge topology first power modules; the isolation level consists of N1 second level power modules, and each second power module comprises a medium high frequency wave chopper part, a medium high frequency transformer part and a medium high frequency synchronous rectifier part; and the low-voltage level consists of N2 level third power modules. The electric power electric transformer skillfully utilizes the prior half-bridge topology structure technique, better solves the problems of low operating efficiency, voltage resistance and voltage sharing of switch devices on the input side and big volume of an input filter existing in the common electric power electric transformer, and simultaneously realizes reactive power control of the high-voltage level and the low-voltage level, quality control of electric energy and limitation of failure current, improves the practicability of the device and quickens commercialization of the electric power electric transformer.

In power conversion according to the three-phase converter, symmetrical component voltage values of a balanced system are calculated from wye-phase voltages on the three-phase AC input side of the three-phase converter. On the DC output side thereof, the power factor is set, an average active power value is calculated from an output voltage value and an output current value, and an average reactive power is calculated from the set power factor. On the basis of the symmetrical component voltage values, the average active power, and the active reactive power, a compensation signal for compensating for unbalanced voltages of the three-phase AC voltages and a control signal for controlling the power factor are generated, and according to the compensation signal and the control signal, a control signal for outputting DC is generated.

The invention discloses a reactive-power control method of a wind power field, which is suitable for performing reactive-power coordinated control on a wind power field variable-speed constant-frequency wind power generating set and a reactive-power compensation device. The control method comprises the steps that: reactive-power requirements of the wind power field are calculated, and a correspondent allocation method is adopted according to the valid reactive-power power capacities of the reactive-power compensation device and the wind power generating set. Due to the adoption of the controlmethod, the reactive-power power adjusting capacity of the variable-speed constant-frequency wind power generating set can be adequately played, the coordinated control of multiple reactive power sources can be realized, and the oscillation situation caused by the adjustment can be avoided. When an electric power system has malfunctions, the reactive power adjustment is locked, so the system over-voltage caused by the excessive reactive power of the system after the malfunction is removed can be prevented. When the reactive power capacity of the wind power field is insufficient to maintain the voltage of an interconnected point, a prompting signal is transmitted, the active power of the wind power field is limited, and the coordination of the active power and the reactive power can be realized.

Systems and methods are provided for reactive power regulation and voltage support for renewable energy plants. In one embodiment, a system and method are provided for coordinating voltage and reactive power output of a plant with one or more requirements associated with a utility. The method can include generating a VAR regulator output signal based at least in part on a reactive power control signal received from a utility, controlling reactive power and voltage output of the one or more power sources based at least in part on the generated VAR regulator output signal, aggregating reactive power output or the one or more power sources, and providing the aggregated reactive power to the utility.

Active and reactive power control for wind turbine generator systems. The techniques described here provide voltage to utilize the total capacity of the wind turbine generator system (400), thereby providing dynamic VAR (Var Support). The VAR support provided by individual wind turbine generators (410, 412) in the system can be changed dynamically to suit usage parameters.

Wind farms and methods for operating wind farms are provided. A wind farm includes a plurality of wind turbine generators. A method includes determining an available reactive power value for each of the plurality of wind turbine generators. The method further includes distributing an individual reactive power command to each of the plurality of wind turbine generators. The individual reactive power command is individually tailored to each wind turbine generator of the plurality of wind turbine generators based on the available reactive power value for that wind turbine generator.

The invention relates to UPS parallel connection equal current control method, the real power controller and the idle power controller are adopted to control the UPS contravariant reference voltage, inductance current direct component is added into the UPS contravariant reference voltage, inductance current direct component of the other UPS in system can be obtained by CAN bus, after DSP calculation of every UPS, the average value of the parallel connection system inductance current direct component is calculated to as the system direct current component, then the given value of the direct current is compared with the direct current component of the UPS inductance current to obtain the difference of the inductance current, the difference passes PI adjustor to obtain the regulated quantity needed by the contravariant reference voltage, and the regulated quantity is used to control the UPS output voltage. So the effective control of the inductance current direct component can be realized, and the direct loop current of UPSs can be eliminated, the flow equalization property and stability of integral UPS parallel connection system can be improved.

The invention relates to a voltage control method applied to a flexible DC power distribution network, which belongs to the technical field of DC power distribution system voltage control. According to the method, a master station adopts constant voltage and constant reactive power control, the master station serves as a slack bus to control system DC voltage, a voltage reference value is provided for the overall DC power distribution network, and when an AC system fails, reactive power support is provided for the AC side. A slave station adopts a P-U-I controller; when the system operates in a steady state, a converter station VSC is in a power control mode PQ, the power is adjustable, the voltage is controllable, power ring control P adjusts output of the VSC according to a system power optimization instruction sent by an energy management system EMS and distribution network power flow is optimized. When the system is in a transient state, the VSC is in a VdcQ mode, voltage ring control U maintains system DC voltage, and the system operates in a rated voltage upper limit and a lower limit. The voltage control method applied to the flexible DC power distribution network has the advantages that the structure is simple, gradation is distinct, realization is easy, the hardware communication cost is greatly saved, system control is simplified, and adaptation and expandability are wide.

The invention relates to the field of protection and control of micro-grids of electric power systems and particularly relates to a micro-grid island fast detection method. The method is sued for an inverter-based distributed generation (IBDG) with a PQ (power quest) decoupling control strategy; a corresponding reactive power control strategy is adopted in the method on the basis of measuring a voltage effective value UPCC and the load reactive power of a common coupling point PCC in real time through comparing the voltage effective value UPCC with the voltage effective value under a normal condition; when island determination is performed, firstly, a voltage threshold value and a frequency threshold value are predetermined, the voltage effective value UPCC is compared with the voltage threshold value, if the voltage effective value UPCC exceeds the threshold value, the PCC is directly determined be in an island state and the island detection is finished, and if the voltage effective value UPCC does not exceed the threshold value, the voltage frequency f of the PCC is compared with the frequency threshold value, the PCC is determined to be in the island state if the voltage frequency f of the PCC exceeds the threshold value. With the adoption of the detection method, the micro-grid island detection can be realized fast, and the effectiveness of the island detection can be ensured even under the existence of a plurality of inverter-based distributed generations.

The invention discloses an inverter grid-connected control method based on the virtual synchronous generator technology and belongs to the field of distributed power generation system grid-connected researches. According to the technical scheme, the method includes the steps that a grid-connected inverter phase voltage phase value is obtained through calculation by simulating a conventional synchronous generator unit active power control method; a grid-connected inverter phase voltage amplitude value is obtained through calculation by simulating a conventional synchronous generator unit reactive power control method; a three-phase voltage reference value is worked out according to the inverter phase voltage phase value and the inverter phase voltage amplitude value, a three-phase modulated wave is figured out according to direct current side voltage obtained through detection, and the three-phase modulated wave is compared with a carrier wave to obtain six switching signals to control turn-off and turn-on of switching devices in a main circuit. System damping and active power-frequency droop control are achieved by means of control link signals, and power grid frequency does not need to be detected. The method simplifies a control structure and avoids the problems caused by a frequency detection link. Effectiveness of the method is verified through simulation and experiment results.

The invention relates to a symmetrical drop-off low voltage ride through reactive power control method of a photovoltaic power generation system. A controller detects whether a grid connection point voltage drops off in real time, and if the voltage does not drop off to 90% of a nominal voltage, an active current reference value id* is taken from an outer voltage loop, and grid connection control when the voltage is normal is adopted; if the grid connection point voltage drops off below 90% of the nominal voltage, the outer voltage ring is disconnected, low-voltage ride through control is adopted, namely inner current loop control is adopted, definite reactive power is output to a power grid by the photovoltaic power generation system according to the drop-off amplitude, and recovery of the voltage of the power grid is facilitated; if it is detected that the voltage recovers, the active power of the photovoltaic power generation system recovers at 10% rated power / second, reactive power is gradually reduced to zero at the same time, and finally the grid connection control when the voltage is normal is adopted. According to the method, an outlet current of a photovoltaic grid-connected inverter is limited within an over-current protection action current, reactive power support is provided for the grid voltage to recover to the normal value, investment of reactive power equipment is saved, and resources are saved.

The present invention relates to a method of reactive power regulation in a wind turbine comprising a local reactive power control system adapted to operate in a central control mode and a local control mode, a method of reactive power regulation in a wind park connected to an electrical grid, and to a wind park.

The invention discloses an optimized control method for wind power field reactive power compensation capacity considering wind power distribution rule; according to the method, a reactive power compensation capacity optimization model is utilized to carry out an optimized treatment, and the optimization target is that investment cost of reactive power compensation and operation cost of wind power system caused by reactive power are minimized; operation cost and investment cost are calculated; the operation cost comprises the affect of wind power distribution result and power property; and an optimized calculation is carried out by utilizing a particle swarm optimization algorithm combined with a power flow calculation program. The method has the beneficial effects that according to the optimization decision method of the compensation capacity, the reactive power compensation of a wind power field has the best economical efficiency and the strongest pertinency on the premise of adequately ensuring continuity of reactive power adjustment by wind power system.

The invention provides an evaluation method based on a voltage reactive power control system in a grid system. Weights are distributed through the utilization of the fuzzy linear transformation theory and the maximum membership degree principle, by taking factors relevant to an evaluated object into consideration and according to the degree of influences of different indexes on the evaluated object, and then reasonable comprehensive evaluation is given. The method includes the steps that firstly, data of the voltage reactive power control system in a grid are acquired; secondly, an index system of a hierarchical model of first level indexes and second level indexes is formulated; thirdly, system running is analyzed and summarized according to running data, analysis data and running state information of all modules, and then running state parameters and the running state of the voltage reactive power control system are acquired, wherein the first level indexes and the second level indexes in the index system serve as analysis and computation objects of the voltage reactive power control system; fourthly, a judgment set of a classification model is determined; fifthly, a comprehensive analysis hierarchical structure is formed through the Delphi method; sixthly, the weights of the indexes are determined; seventhly, comprehensive evaluation of the highest layer A of the comprehensive evaluation index system is computed according to a fuzzy comprehensive evaluation method and model.

A system and method are provided for performing reactive power control. The system includes a power converter and a controller coupled to the power converter. The power converter is configured to convert a first form of electric power generated from the power source to a second form of electric power suitable to be distributed by the electrical grid. The controller is configured to monitor the electric power transmitted between the power converter and the electrical grid. The controller is further configured to decouple a positive sequence component and a negative sequence component from the monitored electric power. The controller is further configured to perform a positive reactive power control and a negative reactive power control with respect to the decoupled positive and negative sequence components. The controller is further configured to transmit a control signal to the power converter based on the positive and negative reactive power control.

The invention discloses a high permeability new energy power grid connection system and stability control method which belongs to the field of a new energy power system. When new energy has high permeability (50% to 100%), a power grid connection system is composed of a prime mover, a motor and a synchronous generator, or is composed of a motor and a synchronous generator. Rotors of the units are coaxially connected. New energy power is transmitted and converted to power the motor. According to the invention, the method is different from a traditional new energy direct grid connection method; a high permeability new energy power system has enough inertia; the frequency stability of the system is improved; the synchronous generator is retained to effectively damp system oscillation; through voltage and reactive power control, the power angle and the voltage stability of the system are improved; the peaking capacity of traditional thermal power and hydropower units and the like is retained; and through coordinated control of the motor, the synchronous generator and the prime mover, the dynamic regulation characteristic of the system is improved.

Methods, systems, controller devices, and computer program products for reactive power control at a renewable energy site are provided. Embodiments address dynamic performance problems associated with control loop delay and the changing modes of operation for meeting utility voltage and reactive power constraints. Provided is a method for reactive power control involving: (a) determining a site-wide reactive power command comprised by a sum of a reactive power feedforward or compensation term and an integrator term; and (b) distributing the site-wide reactive power command among inverters. Embodiments can include a reactive power control term based on the sum of a single integrator and feed-forward compensation term, an integrator anti-windup mechanism based on the status of individual inverters, a means for decreasing detrimental effects of loop delay during reactive power reference changes, and / or a means of implementing voltage and power factor limits with smooth transfer between reactive power operating regions.

A reactive power controller for controlling reactive power in a wind farm grid connected to a utility grid and including at least two sub-grids and a collector portion is provided. At least one wind turbine is connected to each sub-grid, wherein the at least two sub-grids are connected to the collector portion and wherein the collector portion establishes the connection to the utility grid. The reactive power controller includes a device for determining an actual reactive power value at the collector portion, and a wind farm controller operatively connected to the device for controlling at least one of said wind turbines on basis of the determined actual reactive power value such that a desired reactive power value is attained.

A power inverter includes a regulator circuit that controls real and reactive power output by the inverter. The regulator measures real and reactive output power by calculating x-phasor components of the inverter's voltage and current output waveforms. Phasor calculation can be adapted for one or more pairs of single-phase voltages and currents. Determining the fundamental in-phase and quadrature components of output voltage and current reduces computational complexity by permitting the regulator to perform its power control processing largely in a dc signal domain, and enables separate real and reactive power control. The power inverter can include islanding detection logic, which exploits the ability to separately control reactive power. Exemplary islanding detection logic is based on determining whether changing the amount of reactive power output by the inverter induces an output frequency shift.

The invention discloses a regional power grid reactive power optimization method relating to a flexible HVDC system. The method achieves the purpose of regional reactive power optimization on the flexible HVDC AC and DC parallel system and provides a basis for setting reactive power control reference values for a current converter. The method includes the steps of acquiring basic parameters of a power grid, determining a relational expression of voltage, current and power of the flexible HVDC system, establishing a reactive power optimization objective function with power regulation cost of flexible HVDC considered, determining equality and inequality constraints of corresponding variables according to the variables in the objective function, solving the regional power grid reactive power optimization objective function with the genetic algorithm by considering current constraints of the current converter of the flexible HVDC system under different operation modes, and improving power control strategies according to current converter reactive current optimal solutions obtained by optimal computation. According to the method, the active power regulation cost of flexible HVDC and the current constraints of the current converter are considered, and therefore rationality in setting the reactive power control reference values of the current converter is improved.