310 results about "HVDC converter station" patented technology

The invention discloses a direct-current converter station based on a bipolar structure. The direct-current converter station consists of two convertor units connected in series, the serial connection point of the two convertor units is grounded by a neutral bus, and each convertor unit consists of a plurality of MMC (Modular Multilevel Converter) which are connected in series and in parallel. With the structure, when direct current fails, only the fault pole is affected, and a perfect pole is hardly affected, so the system reliability is improved; meanwhile, according to the direct-current converter station, the neutral bus is led out to be grounded, the stage construction and capacity-increasing construction of a system can be conducted easily, and a single pole is firstly put into operation, then double poles are put into operation, so that investment benefits can be obtained early; and simultaneously, the neutral bus is grounded by a grounding pole guide line to provide a current backflow access to a system in a single-pole ground loop operation mode, and when the system is in balance operation, the grounding current is extremely low.

The invention discloses a hybrid direct-current transmission topology structure and a control method. The hybrid direct-current transmission topology structure is characterized in that two groups of thyristor converters are connected in series to form a first converter station, two groups of voltage source type converters are connected in series to form a second converter station, switch elements are respectively mounted at the same positions of the positive ends and the negative ends of the converters, in series connection, of the first converter station or the second converter station or the first converter station and the second converter station, and meanwhile, the same positions of the positive ends and the negative ends of the converters are in parallel connection and crossly connected to the opposite ends through one switch element respectively. The control method includes reducing direct-current power of a direct-current system to zero, and changing states of the switch elements to invert voltage polarity of the direct-current system, thereby achieving overall operation of two poles after inversion of the direct-current voltage polarity or achieving new two-pole direct-current operation by means of crossing of the converters in series connection of the converter stations at both ends. The system of the hybrid direct-current transmission topology structure has advantages of low manufacturing cost as the conventional direct-current transmission and control flexibility as the flexible direct-current transmission, and the like.

In order to provide a converter station for a high-voltage DC connection between two three-phase AC voltage networks, having a converter building which has a number of floors, and in which transformer units, converter devices, filter units, a gas-insulated switchgear assembly with feeder units, at least one cooling system, a DC cable pot head for electrical connection of a high-voltage cable carrying direct current, a smoothing reactor and gas-insulated busbars for electrical connection of these components are arranged, while maintaining its compact design and the arrangement of its components in a closed building, whose cost is low and which has a physically simple design, the invention proposes that the DC cable pot head and the smoothing reactor are arranged on the same floor as the converter valves and are electrically connected to one another via an air-insulated connecting device, with an air-insulated isolating switch being provided in order to produce an isolating gap between the DC cable pot head and the smoothing reactor.

A converter station insulating co-operating design method of a high-pressure direct-current power transmission system belongs to a high-pressure direct-current power transmission system analyzing method, and aims at simplifying calculating working capacity, avoiding excessive man-made interference, and guiding users to highly-effectively finish insulating co-operating analysis. The converter station insulating co-operating design method comprises the lightning arrester configuration step, the system analysis step and the insulating co-operating step. The converter station insulating co-operating design method greatly simplifies the calculating working capacity of insulating co-operating analysis, avoids excessive man-made interference factors of users, and guides users to highly-effectively finish insulating co-operating analysis through a guiding mode.

A power system includes a power generating plant including a plurality of power generators, and an AC collection grid adapted to interconnect the power generating plant and an HVDC converter station. The AC collection grid is adapted to operate outside network regulations, whereby advantages such as simplified control and electronics are achieved. A method of operating a power system is also provided.

The invention provides an on-line monitoring system of a high voltage DC converter valve, comprising a thyristor valve level on-line monitoring plate, an intelligent monitoring cabinet and a background monitoring system. The thyristor valve level on-line monitoring plate calculates the element parameters of elements contained in a damping loop and a DC voltage-sharing loop. The intelligent monitoring cabinet makes the maintenance plan of the converter valve based on the work state of the thyristor valve level and the power value transmitted by each transverter in a converter station. Comparedwith the prior art, the on-line monitoring system of a high voltage DC converter valve is advantageous in that the element parameters of elements in the thyristor valve level can be monitored in a real-time manner, and the maintenance plan of the converter valve can be made, and thereby the fault of the thyristor valve level can be found out in time and maintenance of the thyristor valve level canbe done in time.

A method for melting ice on line of super high voltage DC transmission system adds connection wire and switch in main wiring of super high voltage DC transverting station to change connection relation between transverters and to raise current on transmission line for melting ice on transmission line by changing on-off state of switch correspondingly.

The invention discloses a low frequency oscillation damping control method for an offshore wind power VSC-HVDC output system; Specifically for the offshore wind power via VSC-HVDC output system, in AC/DC hybrid system, DC system operates at rated power, and AC system oscillates at low frequency due to large disturbance, so it is necessary to add damping controller to restrain low frequency oscillation. The invention only needs to be implemented in The DC voltage control of VSC- HVDC converter station and the frequency-based predecessor control only need a proportional link and a filter link.The frequency-based predecessor control of HVDC converter station only needs a proportional link and a filter link. When the low frequency oscillation occurs after the disturbance of AC power network,the change of frequency signal is transmitted to DC voltage, The change of DC voltage will cause the change of active power and damp the low frequency oscillation of AC system, which can not only keep the stable operation of the converter station, but also provide better damping effect for the low frequency oscillation of AC system connected with the converter station, and guarantee the VSC- HVDCdc system operation safety and stability and the friendliness of power grid.

The invention discloses a mixed type three-pole direct current power transmission system and a control method thereof. The system comprises a rectifying converter station and an inverting converter station, wherein the rectifying converter station and the inverting converter station respectively comprise an alternating current bus and a three-pole converting system, each alternating current bus is connected with a corresponding alternating current power grid, each three-pole converting system is hung on each alternating current bus through a converting transformer, and a converting unit H3 of each three-pole converting system adopts an MMC (modular multilevel converter). The system and the method have the advantages that the decoupling control capability of the active and inactive parts is realized, the power can be transmitted to an inactive network, the number of inactive compensation equipment is greatly reduced, the balance of the direct current among the three poles is maintained by introducing the MCC (modified current control), the current of a grounding pole is inhibited, the service life of the grounding pole is effectively prolonged, the on-site balance of the inactive power is realized by introducing the AVC (alternating voltage control), and the voltage of the connected AC (alternating current) system is maintained to solve the overvoltage or undervoltage problem.

The invention discloses a UHV DC converter station dynamic reactive power optimization method in consideration of the coordination function of a phase modifier and a system filtering requirement. Themethod comprises main steps of: 1) establishing a UHV DC converter station dynamic reactive power optimization model M; and 2) by using a hybrid reactive algorithm of dynamic reactive power optimization, calculating the UHV DC converter station dynamic reactive power optimization model M to optimize the UHV DC converter station. According to a DC transmission power plan and a system dynamic reactive standby requirement, the method enables the remaining capacity of a phase modifier to participate in the steady-state reactive voltage adjustment of the converter station, and takes account that the phase modifier has high upper and lower adjustment margins, thereby realizing the coordinate of the phase modifier and the DC system to fully utilize the performance of the phase modifier.

The invention discloses an optimal configuration method for fault current limiters. An area with high risk of failure in simultaneous phase commutation is judged by using a multi-infeed DC interactionfactor. During the configuration of an SRFCL device, the average electrical distance from a current limiting node to the DC converter stations in the area with high risk of failure in simultaneous phase commutation is calculated, and the priority of the current limiting node is determined to avoid large-range search. Meanwhile, the suppression effect of SRFCL on DC commutation failure is considered. Therefore, an SRFCL optimal configuration scheme taking both short-circuit current limiting and commutation failure suppressing into account is realized. The method is helpful for power system planners to grasp the influence of SRFCL installation and configuration on the phase commutation failure of a multi-infeed DC system and visually determine an SRFCL installation area. The indexes in thearea can be displayed in order during calculation. The method is easy to implement. Decision support is provided for the optimal configuration method of SRFCL in the multi-infeed DC system.

The invention discloses a wind power flexible direct current delivery system with a distributed direct current energy consumption device; the wind power flexible direct current delivery system comprises a plurality of offshore wind power plants which are arranged in parallel, wherein electric energy sent out by the offshore wind power plants is fed into an alternating-current power grid through atransmitting end converter station and a receiving end converter station; the distributed direct current energy consumption device is integrated inside the transmitting-end converter station or the receiving-end converter station; when the wind power flexible direct current delivery system suffers from a receiving-end alternating-current fault, the voltage of the direct-current side system rises,a certain number of energy consumption resistors are input for consuming the surplus power, and the short-time stability of the system is maintained; and after the fault is recovered, the corresponding energy consumption resistors are removed, and the fault ride through of the system is completed. According to the system, the energy consumption components are averagely distributed into a large quantum module, so that accurate matching of surplus power can be realized, the fluctuation of the electric quantity in the switching process of the energy consumption device is greatly reduced, fault outage of the system is avoided, and fault ride-through is realized.

A method and system for coordinate control of voltage and reactive power of a camera and an UHVDC convert station. The method comprises steps of keeping the AC filter bank switching strategy of DC control and protection system unchanged, Obtain the filter of DC control and protection, the switch instruction of reactor group, the operation mode and related control parameters and the operation stateof the adjuster, adjust the control target of the adjuster according to the switch instruction of DC control and protection, and intervene the switch instruction of AC capacitor and reactor output byDC control and protection. As that invention is base on the reactive power control of the UHVDC transmission and the exist control mode of the camera, The utility model can reduce the bus voltage fluctuation when the AC filter bank is switched on and off, reduce the switching times of the capacitor and the reactor bank, prolong the service life of the AC capacitor and the reactor, and at the sametime, do not need to change the DC control protection and the internal control logic of the adjuster, so that the utility model is convenient to implement.

A project practical method for thawing ice on an AC incoming line of a HVDC substation is characterized in that a back-to-back converter unit connection is composed of two poles of the HVDC substation; one pole is used as a rectifier, while the other pole is used as an inverter; an AC line is coupled in a pole line of the back-to-back converter unit, so that DC current of the same intensity flows through the AC line as well as the inverter for thawing the ice on the AC line. The experimental method can be used for thawing the ice on the AC incoming line of the HVDC substation. A built DC project can meet the ice-thawing requirement of thawing the ice on the AC incoming line of the HVDC substation through controlling and protecting system reconstruction; and the mode of the back-to-back ice-thawing operation can be added to a new DC project for thawing the ice on the AC incoming line of the HVDC substation.

The invention provides a method for measuring a strength index of interaction between converter stations of a multi-feed direct current system. The method comprises the following steps that (1)a multi-feed alternating current and direct current power grid receiving end system is taken as a research focus, direct current converter stations to be researched are determined, and it is assumed that the number of the direct current converter stations to be researched is N, and the direct current converter stations to be researched have three phases of A, B and C; (2) electromechanical transient simulation calculation is conducted on the power grid with electromechanical transient simulation software, a single-phase grounded short circuit with certain resistance is arranged at the phase A at a converter bus i, i=1, 2, ...N, the change of the voltage of the phase A at the converter bus i is observed, the grounded resistance of the short circuit is adjusted constantly, the voltage of the phase A at the converter bus i drops by 1% after the short circuit, the variation delta UAj of the voltage of the phase A at the converter bus j is recorded, j=1, 2, ..., i-1, i+1, ...N, and the calculation of the phase B and the calculation of the phase C are identical with that of the phase A; (3) a single-phase multi-feed interaction factor SMIIFij between the converter station i and the converter station j is calculated. By means of the method, references are provided for evaluating the strength of the interaction between all converter stations in the multi-feed direct current system in asymmetrical faults.

A method for nonlinear sag control of hybrid multi-terminal HVDC system the method performs nonlinear sag control on a plurality of LCC converter stations in a hybrid multi-terminal HVDC system, As that DC voltage of the HVDC transmission system is changed due to the change in transmission power, the LCC converter station automatically adjusts its transmission power, maintain the power balance ofHVDC system, Moreover, in the process of DC voltage stabilization by multiple LCC converter stations, the converter stations with larger current margin bear larger power variations, while the converter stations with smaller current margin bear smaller power variations, so as to avoid some converter stations losing the ability to respond to power variations due to full load. The invention fully considers the current margin of each converter station, and a plurality of LCC converter stations jointly maintain the stability of the DC voltage, so that the active power of each converter station canbe coordinated and distributed, and the static deviation of the DC voltage of each converter station can be effectively reduced.

The invention relates to a multiport direct-current transmission power coordination control method. An independent multiport controller is arranged in a multiport direct-current electricity transmission system formed by three or more converter stations connected in parallel, a master / slave control structure is adopted to achieve coordination of controllers in the converter stations, the multiport controller serves as a main controller to take charge of power / current definite values of the converter stations, and various converter station pole controllers serve as slave controllers to achieve power / current control of the converter stations. The fact that the whole direct-current system has a stable operation range is guaranteed. The multiport direct-current transmission power coordination control method can meet configuration and switching requirements for normal operation and an operation mode after a fault of the multiport direct-currnet electricity transmission system. When the multiport direct-current electricity transmission system breaks down, if current commands still keep balanced after a certain converter station or a section of a circuit is removed, the rest of the stations of the multiport direct-current electricity transmission system can still operate, and quick recovery of the system after the fault is removed is achieved.

The invention discloses a calculation method of a single-phase multi-feed-in interaction effect factor based on an impedance matrix, comprising steps of determining a DC converter station to be studied by taking a receiving terminal of the multi-feed-in AC power grid and presuming that the quantity of the DC converter station is N, (2) calculating self-impedance Zii-1, Zii-2, Zii-0 of a converter station i in a positive negative zero sequence impedance matrix of the multi-feed-in AC-DC power grid to be studied and the mutual impedance Zij-1, Zij-2, Zij-0,i=1,2-N, j=1,2-N between the converter station i and the converter station j,calculating the positive-negative zero sequence impedance of the converter station and the sum of the positive-negative zero sequence impedance between the converter station I and the converter station j, and (3) calculating the single-phase multi-feed-in interaction effect factor SMIIFij of the converter station I and the converter station j. The invention can quickly obtain the single-phase multi-feed-in interaction effect factor SMIT between the converter station, and can provide reference to the strongness and weakness.

The invention discloses an AC/DC fault identification and protection coordination method in a converter station belonging to the technical field of safe operation of an AC/DC hybrid transmission system. According to the characteristics of DC second harmonic current and AC negative sequence current before and after the converter lockout, the invention puts forward the converter station differentialcurrent protection, which can distinguish AC from DC faults, determine the fault area, and the coordination and cooperation scheme of AC and DC protection. Finally, combined with PSCAD/EMTDC model ofPV/DC convergent access system, the feasibility of differential protection and the reliability of AC/DC protection coordination scheme are verified. The results show that the proposed method can effectively identify AC and DC faults, and is less affected by the transition resistance.

The invention provides a converter station grounding grid surge impedance testing method based on an artificial short-circuit test. The method includes the following steps that firstly, measuring equipment is selected according to the practical converter station conditions such as the surge current range and the surge voltage range; secondly, a signal sampling point where the surge current and the surge voltage are measured is arranged on a converter station grounding switch, the measuring equipment is arranged in corresponding protective chambers, and a surge voltage reference zero-potential point is arranged in the position with a proper distance away from a grounding grid of a converter station; thirdly, according to the measured converter station direct-current line condition, artificial short-circuit test points meeting safety conditions are selected, and grounding frame suspension preparatory work is conducted before the artificial short-circuit test. By the adoption of the method, the characteristic that a direct-current transmission system can form a ground current loop is fully utilized, the large surge current is provided through the transmission system, the problem that the large surge current is difficult to provide on the scene is solved, and the truth of surge grounding impedance is reflected.

The invention provides a UHVDC simplification and simulation model which faces a power characteristic, and belongs to the field of electric power system modeling and simulation. In the UHVDC simplification and simulation model which faces the power characteristic, fast dynamic procedures inside converter stations are omitted, in stable operation of the converter stations, only a response behavior at a backstage after being influenced by a power grid state change is taken into account, and the converter stations at the two sides are equalized to be controlled voltage sources or controlled current sources. A typical operation state in a high voltage direction current transmission system is selected as a preset mode, a change law of a controlled angle of a converter under the preset mode is analyzed, a mathematical expression model of the controlled angle is established, and a controller model is simplified. According to the UHVDC simplification and simulation model which faces the power characteristic, on the basis that enough precision is guaranteed, the adjusting process of the controller is simplified, the simulation calculation amount is reduced, and the UHVDC simplification and simulation model is applicable to electromechanical transient simulation analysis of the converter stations.

The invention discloses a fire warning and video monitoring linkage system of a direct-current converter station. The fire warning and video monitoring linkage system comprises a fire warning subsystem, a video monitoring subsystem and a communication module. The fire warning subsystem and the video monitoring subsystem pass through a communication interface of the communication module and conduct linkage communications based on a Modbus communication protocol, and thus linkage warning can be achieved through data analysis. The specific steps are that the fire warning subsystem sends an address code of a fire sensor in a fire alarm occurring place to the video monitoring subsystem, after the video monitoring subsystem receives the address code of the fire sensor, a camera in an actual area corresponding to the address code of the fire sensor is inquired through an address code mapping table, and the video monitoring subsystem is switched to a corresponding camera picture. By means of the fire warning and video monitoring linkage system of the direct-current converter station, the video monitoring system can immediately and automatically push out the monitoring picture of a fire scene when fire alarm happens, and the original function of an original fire warning subsystem and the original function of an original video monitoring subsystem can not be affected.

The invention relates to a converter station of a flexible DC power grid and a coordination control method for many convertor stations. A DC voltage deviation controller is input to a DC voltage control slave station for running to achieve voltage stability of the DC power grid when a DC voltage master control station and the DC voltage control slave station are abnormal in communication and the DC voltage master control station stops running. By the method, DC voltage control is not needed to be managed by the DC voltage control slave station when the communication is abnormal and the DC voltage master control station stops running, and the problem that the DC power grid works in an abnormal working state caused by that the DC voltage control slave station manages DC voltage control during abnormal communication among stations is effectively solved.

The invention provides a switch locking method of a high-voltage direct current convertor station, comprising the following steps of: realizing switch locking on an I/O interface board operated by a direct current control switch in a direct current control protection system, analyzing commands, such as a switch closing command and the like from each control protection host, by a communication module, sending the commands to a CPU module, and receiving commands of controlling and protecting each subsystem send by a field bus by the CPU module; outputting closing signals to switch equipment by connecting the switch closing command and the input end of an and gate; arranging an RS trigger to be connected with received switch locking judgment; when the I/O interface board receives any one switch locking command but does not receive an unlocking command, outputting the switch signals needed locking by the Q end of the RS trigger; when receiving the unlocking command by the I/O interface board, prohibiting outputting the locked switch signals by the Q end of the RS trigger, and connecting the Q end and the other input end of the and gate through a not gate. The invention protects the safety of primary equipment of the direct current convertor station and has simple realization method without increasing the design complexity of the control protection system.

The invention discloses a construction method of a quasi-steady-state model of a direct-current system under an asymmetric fault. In a direct-current convertor station with extra-high voltage and extreme-high voltage, when an asymmetric fault happens on an alternating-current system, a control center in the station is used for obtaining the waveform information of triple-phase line voltage half cyclic wave of an inversion side alternating-current system, a zero-crossing moment of phase change line voltage is predicted through the practical waveform of asymmetric phase change voltage, a triggering moment of the trigger pulse of each thyristor valve block is improved so as to obtain the numerical values of direct-current average voltage and a phase change angle caused by the consideration of the change of the phase change voltage to obtain an improved quasi-steady-state model of the direct-current system under the asymmetric fault, and therefore, an alternating current/direct current hybrid power system can be quickly and accurately subjected to electromechanical transient simulation.