365 results about "Static VAR compensator" patented technology

The invention discloses a mixed type power quality controlling device comprising an active part and a passive part, wherein the active part comprises active power filters (APFs) and static var generators (SVGs), the SVGs are used for supplying transient reactive power, and the APFs are used for filtering harmonic waves; the number of the APFs and the SVGs is at least two groups, and the APFs and the SVGs are connected with a three-phase power grid in parallel through a transformer isolation mode; the passive part comprises a static var compensator (SVC) which is used for supplying steady-state var power, wherein the SVC comprises a thirstier switching capacitor (TSC), a thirstier control reactor (TCR), and a fixed capacitance compensator (FC); the TSC, the TCR and the FC are directly connected with the three-phase power grid, the TSC is used for supplying high-capacity capacitive var power, the FC is used for supplying low-capacity var power and is also used as a main subharmonic filtering branch circuit to carry out harmonious comprehensive compensation and harmonic control on a power system.

A device and a method for controlling the flow of electric power in a transmission line carrying alternating current, in which a first voltage source converter is connected to the transmission line at a first point and a second voltage source converter is connected to the transmission line at a second point. Further, the first and second voltage source converters have their direct current sides connected to a common capacitor unit. Also included is a by-pass switch connected to the transmission line between the first point and the second point in parallel with the first and second voltage source converters so that the first and second voltage source converters will operate as a back-to-back station when the by-pass switch is open and as two parallel static var compensators when the by-pass switch is closed.

The invention provides an automatic dynamic voltage control (AVC) system for a wind power plant. The AVC system comprises an AVC controller, a plurality of blower main-control systems on a plurality of blowers in the wind power plant and an SVC (Static Var Compensator), as well as a plurality of voltage transformers and current transformers, which are arranged on wind power send-out lines, wind power collection lines, SVC lines, high-voltage buses and low-voltage buses, wherein each wind-power collection line is connected with a plurality of blowers, receives the electric energy output of the plurality of blowers and is connected with the low-voltage buses; the AVC controller communicates with each blower main-control system through an optical network and is electrically connected with the voltage transformers and the current transformers; and the AVC controller determines the total value of reactive power required to be sent out or absorbed by the wind power plant, the total value of the reactive power capable of being sent out or absorbed by all the wind power collection lines, and the reactive power capable of being sent out or absorbed by all the blowers, and sends control signals corresponding to the reactive power required to be sent out or absorbed by all the blowers to the corresponding blower main-control systems.

The invention relates to a winch heave compensation device for an ocean floating drilling platform. The device comprises an active compensator and a passive compensator which are arranged on one side of a winch in parallel. The active compensator comprises a first single-rod piston cylinder with a piston rod stretching upwards and a force transducer, wherein two chambers of the first single-rod piston cylinder are connected to a hydraulic system through a three-position four-way magnetic exchange valve, and the force transducer is used for detecting force on a steel wire rope and electrically connected with a force feedback controller which controls exchange actions of the three-position four-way magnetic exchange valve. The passive compensator comprises a second single-rod piston cylinder with a piston rod stretching upwards. Tops of the piston rods of the first piston cylinder and the second piston cylinder are connected onto a movable pulley, a fixed pulley is further arranged on the drilling platform, and the steel wire rope on the winch is connected with a crown block and a traveling block after bypassing the movable pulley and the fixed pulley sequentially. According to the device, the compensation effect that active compensation and passive compensation are mutually synchronous and promoted can be achieved.

A chain-link converter including one or more phases. The one or more phases each includes one or more series-connected converter cells. The chain-link converter includes a power source connected to a converter cell of one of the one or more phases. A cost-efficient start-up of the converter is provided. The invention also relates to a corresponding static compensator system and a method.

The invention discloses a joint operating system of the static var compensator and active power filter and the control method, which is characterized in that an active power filter and a control device are added in the static var compensator. The control method of balance compensation of three-phase unbalanced loads is used to realize the compensation of load negative sequence current and the technology of specific subharmonic compensation is used to realize the decoupling control of SVC and APF, so as to guarantee the safe and stable operation of the joint operating system. The invention notonly has the basic functions of the SVC, but also improves the filtering performance of the passive filter through APF, suppresses possible resonance phenomena between the passive component and the power grid equivalent impedance, and can realize dynamic management on subharmonic waves.

The invention discloses a co-phase power supply device and a traction power supply system. The co-phase power supply device comprises a first MMC (modular multilevel converter) valve and a second MMC valve. One end of the first MMC valve is coupled to a first power supply arm of a traction transformer, the other end of the first MMC valve is connected with a return wire, and the first MMC valve is used for converting AC (alternating current) voltage of the first power supply arm of the traction transformer into DC (direct current) voltage; one end of the second MMC valve is coupled to a second power supply arm of the traction transformer, the other end of the second MMC valve is connected with the return wire, and the second MMC valve is used for inverting DC voltage transmitted by the first MMC valve into AC voltage which is identical to the second power supply arm of the traction transformer in amplitude and phase. By means of inter-transmission of active energy of the two power supply arms on sides of the traction transformer, negative-phase sequence current can be eliminated, the capacity utilization rate of the traction transformer can be maximized and electric split-phase of a traction network can be eliminated; the MMC valves compensate idle power and harmonic waves of the two power supply arms, and the increase of risk of overhigh harmonic waves of devices such as capacitors, SVCs (static var compensator) and SVGs (static var generator) can be avoided, so that the co-phase power supply device can be applied to comprehensive treatment of power quality of traction transformers.

In a control system for a static var compensator that performs phase control of a current of a reactor for each phase by a thyristor and thus controls reactive power, a detecting unit that detects a tertiary harmonic current flowing through each phase of the static var compensator is provided, and on the basis of the tertiary harmonic current flowing through each phase detected by the detecting unit, the thyristor of each phase is controlled so that the quantity of generated tertiary harmonic current of each phase becomes equal, and therefore an outflow of the tertiary harmonic current toward a system can be restrained by an inexpensive method.

The invention relates to a wind farm reactive comprehensive optimization control method. The method comprises the following steps of: inputting signals into a wind farm reactive comprehensive optimization control system; switching plant or wind farm grid combining point capacitors and reactors, controlling a static var compensator (SVC) and controlling wind farm units by using the wind farm reactive comprehensive optimization control system. Through the scheme, the automatic control level of wind farm scheduling, the utilization ratio of reactive configuration equipment and the voltage stabilization level of a power grid can be improved, and reactive power comprehensive optimization coordination control over wind farms is realized.

The invention discloses a second-order cone optimization-based dispatching method for a power distribution network in a jurisdiction of an electricity-sale company. The method comprises the steps of (10) building an optimal dispatching model for the power distribution network in the jurisdiction of the electricity-sale company; (20) converting the optimal dispatching model for the power distribution network into a second-order cone optimization model; (30) solving the second-order cone optimization model to obtain an optimal dispatching result; and (40) carrying out optimal dispatching configuration on adjustable equipment in the managed power distribution network of the electricity-sale company by employing the optimal dispatching result obtained in the step (30) and determining active power output, reactive power output, an adjustable load and energy storage charging and discharging of a controllable distributed power supply, the reactive power output of a static var compensator and the reactive power output of a renewable energy source. By the method, reactive power dispatching is brought into dispatching of the power distribution network in the jurisdiction of the electricity-sale company, convex relaxation treatment is carried out on power flow constraints, and accurate solving can be carried out by employing a second-order cone optimization method, so that the operation cost of the electricity-sale company is effectively reduced.

The invention belongs to the field of power systems, in particular to a reactive-load compensation equipment application scheme for large-scale wind power delivery system. As for the large-scale wind power delivery system, the invention, aiming to meet the needs of power delivery and wind power access, through reactive power balance analysis in different level years and under different operation modes, provides the capacitive and inductive reactive power demands of each substation in the system, and provides a configuration scheme for low pressure side fixed switching reactive compensation equipment such as capacitors, reactors and the like and dynamic reactive-load compensation equipment such as controllable reactors, static var compensators and the like. The provided configuration scheme can ensure voltage at each point in the system is controlled within a reasonable range under different operation modes, and meanwhile the dynamic reactive-load compensation equipment can meet the requirements of reactive power control of the grid and the voltage under wind power fluctuations with a strong engineering adaptability.

The invention relates to a static reactive power compensator adjusting method used in power transmission system. It comprises three combined regulation control tactics: it controls the reactor (TCR) antennal organs which is controlled by the bus wire thyristor to do perceptual reactive-load power constant adjustment; it controls the power filter device group (FC) and the fixed condenser band to do condenser reactive-load power interval adjustment; it controls the load transformer tapping switch (LTC) to do bus wire adjustment.

The invention provides a static var compensation device current detection method based on transient power balance. The static var compensation device current detection method specifically comprises the following steps of: performing phase locking on the phase voltage of an A phase on the low voltage side of a transformer and the phase voltage of the A phase at a compensation point of a static var compensator (STATCOM); performing abc / pq transformation on the three-phase current n the low voltage side of the transformer according to a direction of a rotation vector of the phase voltage on the low voltage side of the transformer to obtain a reactive DC component of load current; converting the reactive DC component of the load current into a reactive current DC component required to be injected into the compensation point of the STATCOM as a q-axis DC component iqref of the output reference current of the STATCOM according to a transient power balance principle; and performing abc / pq inverse transformation on the iqref according to the direction of the rotation vector of the phase voltage at the compensation point of the STATCOM to obtain a three-phase output reactive current directive value of the STATCOM to control the actual output current of the STATCOM. By the method, the problems of current detection caused by the transformer crossing of the compensation point of the STATCOM and a load current detection point are solved, the STATCOM can be flexibly arranged at any position, and simultaneously, a reactive current detection algorithm is quick in response.

The invention discloses an imbalance compensation and the ant colony optimization method for an SVC. The method is based on a variable structure to control the SVC, wherein, the variable structure control method comprises two aspects of the unbalanced load equalization compensation and the parameter control of a PI controller, wherein, the unbalanced load equalization compensation adopts the SVC compensation susceptance computational method which is based on the synchronous rotation reference coordinate transformation of a virtual symmetrical three-phase system; meanwhile, in the stabilization control of the system voltage, the ant colony algorithm optimization method is adopted to real time adjust and to optimize the parameter kp and ki of the PI controller. The invention ensures that the SVC can not only complete the unbalanced load equalization compensation but also control the stabilization, thereby raising the precision of the susceptance computation of the SVC, guaranteeing the balance compensation of the charge, improving the performance in the stabilization control of the SVC voltage and maintaining the voltage stabilization of a common connection joint. Therefore, the invention has high robustness and high response speed.

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 relates to a direct-current-side voltage control method of a cascaded STATCOM based on chopping-control voltage sharing, and a control circuit. The control circuit comprises a three-phase star-connection inverter, a two-way switch device and a controller, and is characterized in that the three-phase star-connection inverter is connected with a three-phase power grid through three inlet inductors; each phase of the inverter consists of n pieces of 2H bridge inverter circuit modules serially connected with each other and having an independent direct-current-side capacitor; the direct-current-side capacitors of the n pieces of inverter circuit modules are connected in parallel; and a two-way chopping-control switch is respectively connected with both ends of the i direct-current-side capacitor and with both ends of the (i-1) direct-current-side capacitor in parallel connection with the i direct-current-side capacitor, wherein i is a natural number from 2 to n. The direct-current-side voltage control method provided by the invention can effectively and reliably solve the key problem limiting the use of the STATCOM with the structure in a high-voltage large-capacity occasion, and can simplify the control program and the design of a regulator, greatly improve the system reliability, and remarkably lower the voltage-sharing control cost, thereby realizing the reliable application of the cascaded STATCOM in high-voltage large-capacitor power equipment.

The invention discloses a power compensation method and a system for a wind power system, wherein the method comprises the following steps: detecting the voltage and current of a power grid belonging to the wind power system in real time; determining the power requirement quantity of the wind power system according to the voltage and current of the power grid, wherein the power requirement quantity comprises reactive power requirement quantity and / or active requirement quantity; and controlling an SVC (static var compensator) device and / or an energy storage unit to regulate so as to compensate the reactive power / or active power of the wind power system. According to the invention, through the compensation device combined by the SVC device and the energy storage unit, not only can the reactive power required in the wind power system be compensated smoothly, rapidly and accurately, but also harmonic wave can not be generated in the compensation process, at the same time, the active power can be provided, the output of the wind power system can be stablized, the voltage flicker is inhibited effectively, and the stability of the power grid is ensured.

The invention relates to a transformerless STATCOM (Static Compensator) topological structure based on MMC (Modular Multilevel Converter), which comprises three phases; each phase is formed by connecting standard power units of a plurality of modular multilevel converters in series; after series connection, one ends of the standard power units are connected one another, and the other ends are connected with an inductor; the inductor is connected with a charging resistor; and after being connected with a switch in parallel, the charging resistor is accessed to a power grid via another switch. The standard power units adopt the charging resistor and a capacitance to supply DC side voltage. The invention has the advantages that by adopting the structure, a transformer parallel in a traditional STATCOM can be omitted, and therefore achieving the purposes of cost reduction, space saving and simple structure.

The invention belongs to the technical fields of electrical power systems and automation thereof, and discloses an SVC (static var compensator) allocation method for improving the transient voltage security of an electric distribution network. The method is implemented based on a quantitative analysis technique for security and stability of an electrical power system through the steps of embodying the comprehensive influence of SVC allocation schemes on the improvement on system voltage security by using voltage security margin improved-value weighted indexes (referred to as comprehensive improved margins of system voltage) in multiple scenes; and on that basis above, considering the cost of each allocation scheme so as to obtain the performance-cost ratio of each allocation scheme, then, carrying out optimized allocation on the installation site and allocation capacity of an SVC through taking the largest performance-cost ratio as a goal.

The invention discloses an electromagnetic hybrid device and a method for synergetic compensation of the high-speed railway multi-station electric energy quality. Active power three-phase transfer of a multi-station traction power supply system is achieved by the aid of an RPC (railway power conditioner), reactive power of designated capacity is outputted for compensation, bus negative sequence components are further reduced with power factor guaranteed, and an MSVC (magnetic-control static var compensator) outputs reactive power to compensate residual bus negative sequence current. By the aid of multi-station synergetic optimum compensation and RPC power transfer characteristics, installed capacity of the MSVC is effectively saved, local dynamic response speed is increased, manufacture cost of the whole device are reduced, and running reliability of the whole device is improved. The device and the method can be used for compensating the electric energy quality of the electrified railway traction power supply system and particularly used for negative sequence compensation, reactive compensation and harmonic wave filtering, and have good application prospect on the occasions that high-speed railways are extremely unbalanced in load.

The invention discloses an AVC (Automatic Voltage Control) joint-debugging control method based on the var compensation technology, which comprises the following steps of: installing and configuring a static var compensator (SVC) in a power grid; obtaining the real-time information of the SVC by a control system for the AVC; according to an SVC parameter model and constant value information in the AVC joint-debugging system, carrying out voltage reactive power optimization joint-debugging strategy calculation by combining with the voltage reactive power real-time information; and regulating the SVC and other SVCs with the fixed volume in the power grid. According to the AVC joint-debugging control method, the SVC in the station and the original static reactive power compensation equipment can be controlled in a coordination mode.

The invention discloses a thyristor valve block of a static var compensator (SVC), which comprises one group or more than one group of mutually-tandem anti-parallel thyristor unit modules, resistance-capacitance protection unit modules, plate unit modules, frames and insulators, wherein the anti-parallel thyristor unit modules, the resistance-capacitance protection unit modules and the plate unitmodules are fixed on the frames; each resistance-capacitance protection unit module comprises a capacitor and a resistor; the insulators are fixed on the frames; the insulators are used for supporting and fixing the frame of the thyristor valve block; and each anti-parallel thyristor unit module comprises a thyristor and a profile self-heat dissipation structure, wherein the thyristor and the profile self-heat dissipation structure are pressed and combined together, and the heat dissipation of the thyristor is realized by heat conduction and convection. The thyristor valve block described by the implementation mode in the invention has the advantages of small volume, simple structure assembly and few hidden troubles and is easy to detect and maintain, the valve block can determine the tandem quantity according to the actual capacity conditions of users, and the self-heat dissipation mode is especially suitable for the SVC with medium or small capacity.

The invention provides an anti-oscillating self-adaptive restraining system of subsynchronous oscillation of a large-size generator set. The anti-oscillating self-adaptive restraining system of the subsynchronous oscillation of the large-size generator set comprises a signal measurement control system and a static var compensator system, wherein the signal measurement control system is used for enabling measured torsional mode components of the large-size generator set to be through the processing of measurement, inverse amplification, lowpass filtering and self-adaptive control parameter generation in sequence to obtain a needed control signal and enabling the control signal to be input into the static var compensator system, the static var compensator system is used for controlling a triggering angle according to the control signal generated by the signal measurement control system so as to adjust equivalent admittance of the static var compensator system, then reactive power output by the static var compensator system is changed in a self-adaptive mode, corresponding damping torque is generated, and accordingly self-adaptive restraining of the subsynchronous oscillation of the large-size generator set is achieved. The anti-oscillating self-adaptive restraining system of the subsynchronous oscillation of the large-size generator set is capable of better restraining the occurrence of the subsynchronous oscillation of the large-size generator set.

A method is provided for controlling a wind power plant, in particular in case of a frequency drop in a utility grid to which the wind turbines are connected, the method including: Combining demand response, inertial response and spinning reserve for given wind speeds in order for wind power plants to deliver fast aggregate under frequency response for a wide wind speed range with minimal recovery time and minimal production loss at each wind speed. In case of the frequency drop the utility grid is additional stabilized by active power, which is provided from a static VAR-compensator and which is fed into the grid. The static VAR-compensator is connected with the wind turbine via a transmission system. The static VAR-compensator is based on using super-capacitors thus it can provide an amount of active power for grid support in case of the frequency drop.

The invention discloses a reactive optimal online control method for analyzing mixed economic pressure difference and sensitivity. The reactive optimal online control method comprises the steps of preparation of power grid data, calculation of an economic pressure difference optimal initial value, online sensitivity analysis and calculation, a P-Q load flow calculation method considering SVC (Static Var Compensator) static model, a construction method of a dynamic reactive power source, an iteration convergence criterion method and real-time automatic equipment control. With the adoption of the method, by monitoring the running state of a power grid and combining the actual running condition of the power grid, switching of a capacitor and an electric reactor equipment switch in a reactive optical control equipment, fine control on reactive power of SVC dynamic reactive compensation equipment and power plant reactive power generation regulation are realized, an optimization algorithm is improved, a new iteration solving mode is put forward, the dynamic reactive power source is built to carry out practical treatment, a solving method is selected for calculation of a layered node optimized voltage, and an iteration convergence criterion is improved, thus improving the convergence and the practicability of the economic pressure difference optimization algorithm.

The invention relates to an STATCOM control method based on a multi-model fuzzy neural network PI. The method comprises the steps of S1, dividing the distribution system into three models, i,e., Mi (i=1, 2, 3) according to the reduced amplitude value of the voltage Upcc of an access point after a load side of a distribution system is connected with different impact loads; S2, designing a d-axis PI controller PIdi (i=1, 2, 3) and a q-axis PI cotroller PIqi (i=1, 2, 3) for each of models; and S3, enabling the fuzzy neural network model to comprises a fuzzy controller and a neural network. Control parameters kp and ki of the the d-axis PI controller PIdi (i=1, 2, 3) and the q-axis PI cotroller PIqi (i=1, 2, 3) in the Mi (i=1, 2, 3) are adjusted through the fuzzy neural network model. The method has the advantages that 10, the PI controller adopts a multi-model technology, and PI parameters are selected according to a model index in the technology, so that the PI controllers can adapt to the changes of the load of the access point; and 2), the control parameters kp and ki are adjusted by the fuzzy neural network, and complex workload caused by manual PI parameter adjustment is reduced greatly.

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 relates to an MCR (magnetically controlled reactor) soft start and SVC (static VAR compensator) dynamic reactive compensation device as well as a soft start and dynamic reactive compensation method. The device comprises an MCR branch and an FC branch as well as a control system, wherein the MCR branch comprises an MCR, a magnetic control unit and a start switching loop as well as a running switching loop; the MCR is connected with the start switching loop and a motor M in series and is in parallel connection with a network system busbar; a parallel connection bypass of the running switching loop is connected between the grid system busbar and the start switching loop; controlled silicon of the magnetic control unit is connected with an auto winding tap of the MCR; and when the MCR is used as a soft start device of the motor in the process of starting the motor M, and when the motor runs or is idle, the MCR branch and the FC branch are used as dynamic reactive compensation devices. The device and method provided by the invention can be suitable for the soft start of a high-voltage motor and the reactive dynamic adjustment of a network at the same time, and can be used to realize multiple functions and reduce the investment cost of equipment at the same time; and the structure is simple as well as has the advantages of low manufacturing and running cost, simple operational maintenance, good performances, stability and reliability.

The invention discloses a multi-side voltage reactive power coordination optimal control system for a transformer substation. The multi-side voltage reactive power coordination optimal control system for the transformer substation comprises a magnetically controlled reactor (MCR) at a medium voltage side, an MCR-type static var compensator (MSVC) at a low-voltage side, a medium-voltage bus, a low-voltage bus and a voltage and current mutual inductor, wherein the medium-voltage bus, the low-voltage bus and the low-voltage side are configured with capacitor groups respectively provided with a virtual air gap controllable reactor to provide inductive reactive power compensation; the capacitor group is configured on the low-voltage side to realize the continuous regulation from inductive reactive power to capacitive reactive power; the transformer substation is subjected to multi-side voltage reactive power coordination optimal integrated control; the coordination optimal control is carried out by the MCR at the medium voltage side and the MSVC at the low-voltage side. According to the virtual air gap controllable reactor of the multi-side voltage reactive power coordination optimal control system for the transformer substation, which is disclosed by the invention, the adjustable volume of the controllable reactor can be realized.