395 results about "Static var generator" patented technology

The invention discloses a reactive phase modulation method for a photovoltaic power station. Active power is emitted while own reaction output capacity of a grid-connected inverter is fully utilized as a supplement or a substitute of reaction compensation equipment, and configuration capacity of an SVG (static var generator) in an original photovoltaic power station is reduced to greatest extent or even without configuring the SVG, so that cost of the photovoltaic power station is greatly lowered; a reactive phase modulation subsystem uses a multi-target dynamic optimization algorithm to dynamically calculate a reactive target value of each power generating node, large occupied area of the photovoltaic power station and position dispersion of a photovoltaic array are taken into consideration, reactive in-place balance is realized, and flowing of reactive power is reduced; factors like geographical position of the photovoltaic array, type of the inverter and optimal working interval are taken into consideration, so that realization of reactive balance is guaranteed while maximization of active power output by the whole station is realized, whole-station optimal adjusting and economical running of the photovoltaic power station are realized, and the reactive phase modulation method has higher engineering application value.

The invention provides a voltage quality control (VQC) system based on a static var generator (SVG) and a method thereof in the voltage reactive power integration control technical field. The system comprises dynamic reactive power generators, a voltage reactive power automatic controller and fixed reactive compensation circuits. A plurality of dynamic reactive power generators and a plurality offixed reactive compensation circuits are in parallel connection to connect with a bus connecting with an output terminal of an electric power system transformer, and output continuous capacitive reactive power and induction reactive power dynamically. An input terminal of the voltage reactive power automatic controller is connected with the dynamic reactive power generators and the fixed reactivecompensation circuits respectively and outputs a control instruction. According to the invention, speed of static var integration controlled by the voltage quality control is raised.

The invention discloses a hybrid dynamic reactive compensation apparatus and method. The method comprises a mutual inductor, a reactive compensation controller, a thyristor switched capacitor, and a static var generator. To be specific, the mutual inductor is used for collecting a voltage analog signal and a current analog signal of a low-voltage system. The reactive compensation controller is configured to be connected with the mutual inductor to receive the voltage analog signal and the current analog signal and calculate a capacity value of a putting part of the thyristor switched capacitor and a capacity value putted by the static var generator and is configured to be connected to the thyristor switched capacitor to send a first control signal out according to the capacity value of the putting part of the thyristor switched capacitor. The thyristor switched capacitor receives the first control signal and is configured to be connected to a low-voltage system to send a first response reactive current out. The reactive compensation controller is configured to be connected to the static var generator; and the static var generator is configured to be connected to the low-voltage system. According to the hybrid dynamic reactive compensation apparatus and method, the costs are reduced and the compensation precision is improved.

The invention relates to a harmonic-var comprehensive compensation system based on two-way dynamic reactive power compensation devices. The system consists of a mechanically switched capacitor MSC, a static var generator SVG and an active power filter APF which are connected with a power network 1. The system uses the SVG to replace a thyristor controlled reactor TCR in the prior harmonic-var comprehensive compensation system, and as the SVG generates reactive power through electric-energy transformation to perform var compensation, the SVG does not need large-capacity reactors, capacitors and other energy storage elements. Therefore, the capacity of the MSC and the SVG is reduced by half at least; system volume is effectively reduced; and system cost is lowered. Meanwhile, as the SVG uses a full-controlled switching device IGBT, the SVG is fast in response and has the system response time which is less than 20 ms and much superior to that of the TCR. In addition, as the SVG does not produce harmonic current, the capacity of the APF is reduced, thus the volume and cost of the system are further reduced.

The invention discloses a transformer isolated static Var generator and a control method thereof. The transformer isolated static Var generator comprises current transformers, voltage transformers, a boosting transformer, a static Var generator (SVG) starting device, resistance-capacitance (RC) filtering branches, module current transformers, output reactors and converter units, wherein the output ends of at least two converter units are connected with the output reactors; after passing through the RC filtering branches for higher harmonic filtering and passing through the SVG starting deviceconsisting of output end resistors and contactors, the output of each converter unit is connected in parallel at a low voltage bus; after total current is synthesized, voltage is boosted to a power grid voltage by the boosting transformer; each module is connected with the module current transformer; the low voltage bus is connected with a low voltage side voltage transformer and a low voltage side current transformer; and a high voltage bus is connected with a power grid side voltage transformer and a power grid side current transformer. By the technical scheme provided by the invention, theoutput current and SVG capacity of the static Var generator are increased, the SVG is endowed with higher harmonic filtering capacity, and system redundancy is increased.

Disclosed are an unbalanced-load-inhibiting SVG (Static Var Generator) and a control method. Traditional SVGs with three-phase three-bridge-arm main circuit topology structures are only applicable to a three-phase three-wire system. However, in practical application, three-phase four-wire systems and unbalanced systems exist in large quantity, wherein zero-line current also causes comparatively great harms. The unbalanced-load-inhibiting SVG includes a three-phase four-bridge-arm inverter (2) which is connected with a three-phase AC power supply (1) and an isolation driving circuit (3). The isolation driving circuit is connected with a DSP2812 chip (4). The DSP2812 chip is connected with a voltage Hall module (5) and a current Hall module (6). The current Hall module is connected with the three-phase AC power supply. The three-phase AC power supply is connected with a load (7) and a voltage zero-cross detection module (8). The unbalanced-load-inhibiting SVG and the control method are used for electric-energy quality improvement of power grids.

The invention relates to a novel hybrid intelligent dynamic reactive power compensation system and a control method thereof which are used to conduct reactive power compensation adjustment on a grid. Through efficient coordination and control of a SVC (Static Var Compensator) compensation branch and a SVG (Static Var Generator) compensation branch, the intelligent dynamic reactive power compensation system therefore has the advantages of having the capability of accurate compensation and transient response, realizing continuous and smooth adjustment from capacitance to inductance within the scope of capacity, effectively solving reactive mutation problem caused by impact load, effectively suppressing grid voltage flicker and drop caused by heavy load start-stop situation or fault conditions and improving system output. Meanwhile, with the SVC compensation branch and the SVG compensation branch combined, the reactive power compensation system is optimized in terms of compensation characteristics, cost, reliability and the like, thereby being more cost-effective.

The invention discloses an integrated governance device for electric energy quality. The integrated governance device comprises a static var generator and a static var compensator; the static var compensator comprises a fixed compensator and a thyristor control electric reactor; the static var generator, the fixed compensator and the thyristor control electric reactor are connected on a power grid between an electric network source and a load in parallel; each static var generator comprises one or more than two H-bridge units connected in series; direct current support capacitors are connected to two ends of the H-bridge units in parallel; each fixed compensator comprises a capacitor and an electric reactor which are connected in series; each phase of thyristor control electric reactor comprises a phase-control reactor and a controllable valve body composed of one or more than two reverse parallel thyristors connected in series, and the controllable valve body is connected with the phase-control reactor in series. The device not only can compensate as to idle work, but also can achieve the compensation of a harmonic wave and a negative sequence. Meanwhile, the idle work and harmonic wave are continuously and adjustably compensated at the high-voltage side, and no transformer is led, so that the compensation speed is fast.

The invention relates to an adjusting method based on comprehensive considering of voltage and reactive power for an SVG (Static Var generator) of a wind power plant, belonging to the technical field of automatic voltage and reactive power adjusting of a wind power plant. The method comprises the following steps: correcting target voltage values into an upper limit value and a lower limit value according to emergency upper and lower limits of voltage, a qualified bandwidth of voltage and a voltage adjusting dead zone; determining whether to carry out "constant-voltage" adjusting or "constant reactive power" adjusting according to the condition whether the current voltage is beyond the range of the lower limit value to the upper limit value or not; when carrying out "constant-voltage" adjusting, determining the reactive power adjusting variable according to the out-of-limit amount; when carrying out "constant-voltage" adjusting, determining the reactive power adjusting variable according to a target reactive power value; and verifying the reactive power adjusting variable according to the upper and lower limits of voltage and a reactive power adjusting step length. According to the adjusting method, the voltage of a point of common coupling is given a priority to be controlled between the upper and lower limits required as dispatching; therefore, the voltage qualified rate of the wind power plant is improved, the accurate adjustment of reactive power output can be realized under the condition of qualified voltage, and the operation safety and reliability of the wind power plant can be improved.

The invention discloses a comprehensive compensation system for a Vv wiring traction substation with out-of-phase and in-phase compatibility. On the secondary side of a traction substation, both a leading phase (T1-N) and a lagging phase (T2-N) supplies a traction load with power. The direct current sides of a first static var generator (SVG1) and a second static var generator (SVG2) are arranged in a back-to-back way, the alternating current sides of the SVG1 and the SVG2 are respectively connected with the leading phase (T1-N) and the lagging phase (T2-N) of a Vv traction transformer, the comprehensive compensation system which is compatible with out-of-phase and in-phase structures and easily develops and transforms from an out-of-phase mode to an in-phase mode is formed so as to generate a negative sequence power flow opposite to the traction load, and reactive compensation and harmonic suppression are combined through reasonable control. The application of the system is flexible, in-phase power supply is easy to realize, power phase splitting at the exit part of the traction substation is cancelled, and power supply bottleneck is eliminated.

The invention relates to a method for solving three-phase voltage imbalance by using an SVG (Static Var Generator). The method comprises the steps of sampling, filtering, phase correcting, proportional amplifying and operational processing. A comprehensive control quantity obtained by operating and processing is converted into an IGBT (Insulated Gate Bipolar Translator) triggering time through a function; a controller is used for controlling the IGBT triggering time by taking a PT (Potential Transformer) signal as a synchronous signal; therefore, an all-controlled converter in the SVG generates a voltage signal which is same as the three-phase difference value of a power grid and opposite in direction to offset unbalance voltage in the power grid; and a purpose of balancing the three-phase voltage is achieved. According to the method, by adopting the all-controlled converter, the three-phase voltage imbalance problem can be solved effectively; the response speed is rapid; the tracking precision is high; and the stability and the reliability of the power grid can be greatly improved.

The invention discloses a microgrid testing system, which comprises a photovoltaic power generation system, a main energy storage battery system, a power quality management system, a large-sized power load, a super capacitor, a reserved alternating current (AC) bus, a reserved direct current (DC) bus, a microgrid bus and the like. The power quality management system comprises an active power filter (APF) and a static var generator (SVG); the microgrid bus is also provided with a voltage sensor and current transformers; the large-sized power load accesses to the microgrid bus through a variable frequency starting device; a connecting line of the variable frequency starting device and the microgrid bus is provided with a first current transformer; the reserved DC bus accesses to the microgrid DC/AC inverters and solid-state relays; and the photovoltaic power generation system and the main energy storage battery system access to the microgrid bus through interconnection switches. By adopting the microgrid testing system disclosed by the invention, experimental researches, such as microgrid coordinated operation, grid-connected and off-grid control and switching, off-grid belt large-sized power load black start microgrid power quality management and the like, can be conveniently performed, and a testing basis is provided to the popularization and application of a microgrid.

The invention discloses a control method for high-power reactive and harmonic dynamic hybrid compensation method. The hybrid compensation system comprises an SVG (static var generator), a TSF (thyristor switched filter) group and a controller, and the SVG and TSFs are parallelly connected to a grid. The three-phase current of the grid between the SVG and the TSFs is taken as a detection object, voltage and current values collected by sensors are processed through the controller, switching signals of the TSFs are acquired according to hybrid logic judgment, most of the reactive power of loads is compensated in a graded manner, and specific subharmonic is filtered out; control parameters of the SVG are acquired according to an instantaneous-power theory, and the surplus reactive power and harmonic of the loads are continuously compensated. A cost-effective scheme for rapid continuous compensation of the high-power reactive and harmonic is provided, impact of switching of passive equipment on the grid can be completely avoided, and harmonic current is avoided flowing to the grid, so that the control method is energy saving, emission reducing, green, environment friendly, good in social and economical effectiveness, wide in application range and especially applicable to the field of oil drilling.

The invention discloses a single carrier control method applicable to a cascaded SVG (Static Var Generator). The method comprises the following steps: acquiring the instantaneous values of power network voltage, grid-connected current, reactive instruction current and the direct current side voltage of each cascaded H bridge unit through a detection link and generating an SVG voltage modulating signal through voltage current double loop control; rounding off the voltage modulating signal, comparing the 'decimal part' acquired by rounding off with a single-channel triangular carrier signal to acquire one path of pulse signal P1, and adding the P1 and the 'integer part' acquired by rounding off to obtain one path of multilevel pulse signal; and distributing on-off action to a semiconductor power device according to the multilevel pulse signal, the current on-off state of a cascaded branch, the sequencing of direct current side voltage and the polarity of the grid-connected current so as to stabilize the direct current side voltage of each cascaded H bridge and control the grid-connected current. The harmonic characteristic of the method is more excellent than that of carrier phase-shift modulation; the on/off of power devices in the cascaded H bridges can be controlled by a single-channel triangular carrier; and the method is easy to implement.

The invention discloses an comprehensive compensation instruction current obtaining method of an angle-shaped chain-type SVG of a power distribution network. The method comprises the following steps of detecting load currents of ila, ilb and ilc; obtaining load current fundamental active components through ip-iq conversion based on an instantaneous reactive power theory and LPF (lowpass filtering); subtracting the load current fundamental active components from the load current and negating the calculation result to obtain line current compensation instruction signal load currents ia*, ib*, ic* which contain fundamental reactive components, fundamental negative sequence components and reactive components; performing matrix transformation and LPF on the line current compensation instruction signal load currents to obtain a fundamental negative sequence active component and a fundamental negative sequence negative component; and multiplying the fundamental negative sequence active component and the fundamental negative sequence negative component with cos (omega t) and sin (omega t) respectively to obtain a zero sequence loop current instruction i0*, and combining the line current compensation instruction with the zero sequence loop current instruction to obtain an angle-shaped chain-type SVG phase current instruction iab*, ibc* and ica*. The comprehensive compensation instruction current obtaining method of the angle-shaped chain-type SVG of the power distribution networkload current instantaneous value takes load current instantaneous value to achieve simple calculation and can be effectively combined with an existing single-phase chain-type SVG control strategy to achieve an angle-shaped chain-type SVG comprehensive compensation function.

The invention provides a control method for a low-voltage static var generator based on a voltage space vector, and belongs to the control methods for the low-voltage static var generators. The method comprises the steps that an actual output current and command current of a STATCOM are detected according to a STATCOM detection unit, an error current vector delta is determined, and a STATCOM mathematical model is combined to determine a constraint condition of an equivalent error voltage; the STATCOM adopts a double hysteresis control method, the width of an inner loop of a hysteresis loop is I<w1>, the width of outer outer loop of the hysteresis loop is I<w0>, when ||delta|| is grater than I<w0>, the error current vector delta is determined to be at the outer loop, and the current inner loop adopts an internal model controller to accurately calculate an output voltage u<c>* of the STATCOM; when the ||delta|| is greater than I<w1> and less than I<w0>, the error current vector delta is determined to be at the inner loop, a system is in a stable state, and a voltage vector method is adopted to control the STATCOM to output a fundamental voltage vector in a sampling period; when the ||delta|| is less than I<w1>, the error current is located in a dead zone, the on-off state remains unchanged, and the stability of the system is improved. A voltage space vector modulation method and the hysteresis control method are combined, the compensation precision is high, the response speed is fast, the switching frequency is low, and the performance requirements of the STATCOM are met.

The invention discloses a method for designing parameters of LC coupling type SVG (static var generators) in unbalanced power grids, and a method and a system for controlling the LC coupling type SVG.The methods and the system have the advantages that reactive and negative-sequence currents in the unbalanced power grids can be compensated by the aid of the method for designing the parameters whenminimum voltages are required by direct-current sides; voltages inverted and outputted by the VSC are lower than voltages of the power grids when the LC coupling type SVG determined by the aid of themethod for designing the parameters are used for compensating capacitive reactive power, accordingly, capacitive voltages on the direct-current sides can be lowered to a great extent, power and switching loss can be reduced, and the cost can be decreased; the method for controlling the LC coupling type SVG is based on unbalance control strategies with combination of compensation reference voltagedetection of improved SOGI (second-order generalized integrators) and QPR (quasi-proportional-resonant) control, compensation reference currents are directly tracked and controlled by the aid of theQPR control in alpha beta coordinate systems, integral control links are quite simple, and delay and errors in control procedures can be eliminated.

The invention relates to a method for controlling a parallel power quality regulator through non-harmonic detection. A main circuit is only composed of a three-phase LCL filter and a three-phase IGBT inverter bridge and is connected to the output end of a three-phase power grid. The three-phase IGBT inverter bridge is composed of a three-phase IGBT bridge and a direct current side capacitor. Harmonics, negative sequences and unbalance of load currents do not need to be detected through a complex detection algorithm, only the load currents need to be sampled, active current components in the load currents are offset through direct current side voltage stabilizing commands, and then harmonic, negative sequence and unbalance current commands are acquired. The complex detection algorithm is omitted, errors and time delay caused by the detection algorithm are avoided, and the dynamic response speed is increased; meanwhile, resources of a control chip are saved, and economical efficiency is improved. Compared with an existing active power filter, an existing static var generator and an existing static synchronous compensator, the parallel power quality regulator has certain advantages, certain practical value and certain application prospect.

The invention discloses an angle form chain-type static var generator (SVG) directive current extraction method considering negative sequence compensation. The angle form chain-type SVG directive current extraction method considering the negative sequence compensation comprises a chain-type SVG. The chain-type SVG comprises a three-phase chain link. Each chain link comprises a plurality of H bridge cells which are connected in series. The three-phase link is respectively connected with an electric reactor in serious to form a chain link subcircuit, and after being connected, three chain link subcircuits are accessed between a three-phase power grid and a three-phase load. The angle form chain-type SVG directive current extraction method considering the negative sequence compensation can be applied to a negative sequence, reactive and harmonic current comprehensive compensation system based on the angle form chain-type SVG, and is clear in physical significance and simple in algorithm.

The invention discloses a test circuit of a dynamic reactive power compensation and harmonic control device and a test method thereof. A static var generator (SVG) is used as a device for testing a test object, wherein a power main inlet wire is connected with a miniature test bus; the SVG is connected with the miniature test bus after being connected the test object in parallel; a SVG branch current transformer and a test object branch current transformer are sequentially connected in series with circuits of the SVG and the test object; a SVG branch grid-connected circuit breaker and a test object grid-connected circuit breaker are also connected in series with the SVG and the test object; and the tripping outlets of the SVG branch grid-connected circuit breaker and test object grid-connected circuit breaker are in parallel connection. The test circuit not only can be used for effectively testing the dynamic adjustment function, filter function and output capacity continuous change function of the tested reactive power compensation device, but also can be used for achieving full-capacity test, temperature rise test and negative sequence compensation capability test of a large-capacity dynamic reactive power compensation device in a system with small power capacity.

The invention discloses a DSP-based static var generator control system and control method. The control system comprises a signal conditioning circuit, a sliding mode controller, a non-inductance L decoupling controller, a space vector modulator, a drive circuit, a three-phase bridge circuit and a power system. By comprehensive control of a sliding mode variable structure and PI adjustment, control on capacitor voltage at a DC side and fast tracking compensation for reactive current can be achieved; the design is simple; and implementation is facilitated. Through sliding mode control and feedforward decoupling control of non-inductance parameters L, the control system has relatively good robustness on external interference and system parameter disturbance; the reactive current can be relatively well tracked dynamically; the fast reactive compensation performance of a static var generator is fully developed; and the DSP-based static var generator control system and control method can be more widely applied to engineering practice.

The invention provides a full-power aging test method for a current transformer. The method is specially characterized in that: the power grid voltage is connected with the input end of a voltage regulator through an air switch; the output end of the voltage regulator is connected to a primary coil p of a transformer, and a secondary coil s1 of the transformer is connected to a current transformer to be tested and the input end of a debugging module; and the output end of the debugging module is connected with another secondary coil s2 of the transformer. The full-power aging test of the current transformer can be finished by adjusting the voltage regulator to simulate the change of the power grid voltage and through the changing harmonic wave and output current generated by the debugging module. With the full-power aging test method, the current transformers of a high-power uninterrupted power source UPS, an active power filter APF, a static var generator SVG and a photovoltaic inverter can be tested, debugged and aged; the cost in circuit reconstruction is reduced; and debugging aging is fed back to the power grid through a closed loop, thereby saving electric energy.

The invention relates to a high-voltage static var generator (SVG) without a starting circuit and a method for connecting the SVG to a power grid, which can realize safe power grid connection without a starting circuit. The high-voltage SVG is characterized in that after being connected in parallel, a static contact of a master switch and a static contact of a control switch form a system interface with one end of a control system device; a moving contact of the control switch is connected with the input end of a current-limiting resistor; the output end of the current-limiting resistor is connected to the input end of a reactor after being connected with a moving contact of the master switch in parallel; the output end of the reactor is connected with an inverter; and a direct current-side capacitor is externally connected with the inverter. The high-voltage SVG and the method have the following positive effects: the special starting circuit is omitted, the current-limiting resistor and the power grid connection assisting switch are added, and the traditional starting circuit is replaced by the current-limiting resistor, the assisting switch and the control device; and after power grid connection, the current-limiting resistor is automatically short-connected via the master switch, and the high-voltage SVG is changed to the working state, thus realizing safe, rapid and automatic power grid connection.