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50results about How to "Avoid commutation failure" patented technology
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Commutation failure detection method based on commutating current time area index
The invention discloses a commutation failure detection method based on a commutating current time area index. The commutation failure detection method is characterized in that a conception of the commutating current time area is provided for a commutation process of an inversion side of a convertor station for a direct current system according to an area defined by commutating current and a timeaxis; the physical significance of the commutation process is disclosed in terms of energy by a commutating current time area method; corresponding criteria are provided according to the magnitude ofthe commutating current time area; and the criteria can be used as a new index for correctly judging whether the inversion side of the convertor station has commutation failure or not.
Owner:SICHUAN UNIV
Hybrid direct-current transmission converter and direct-current transmission device
ActiveCN104578130AAvoid commutation failureInhibit injectionPower network operation systems integrationElectric power transfer ac networkThyratronVoltage source
The invention discloses a hybrid direct-current transmission converter. The hybrid direct-current transmission converter is provided with four topological structures which are series connection circuits formed by combining anodes and cathodes of current source type valve group units and positive electrodes and negative electrodes of voltage source type valve group units in different modes. Each current source type valve group unit only comprises a current source type valve group or comprises a current source type valve group and a bypass switch or comprises a current source type valve group, a bypass switch and a disconnecting link assembly. Each voltage source type valve group unit only comprises a voltage source type valve group or comprises a voltage source type valve group and a bypass circuit or comprises a voltage source type valve group, a bypass circuit and a disconnecting link assembly. A direct-current transmission device composed of the hybrid direct-current transmission converter effectively solves the problem of commutation failures of a direct-current transmission system based on thyristors and the problem of direct-current faults of a direct-current transmission system based on a voltage source converter, and has the advantages that loss is low, a reactive compensation device is not needed or a small number of reactive compensation devices are needed, and the direct-current transmission device can be connected into a passive alternating-current system and has the inverse power output function.
Owner:NR ELECTRIC CO LTD +1
Method for starting ultra-weak receiving-end high-voltage direct-current power transmission system by using static synchronous compensation
InactiveCN102891497AAchieve normal startupReduce commutation failuresFlexible AC transmissionElectric power transfer ac networkVirus wartsHigh-voltage direct current
The invention discloses a method for starting an ultra-weak receiving-end high-voltage direct-current (HVDC) power transmission system by using a static synchronous compensator (STATCOM), belonging to the technical field of HVDC power transmission. The system is characterized in that a STATCOM and HVDC are connected to a same bus of an alternating-current system in parallel, and a STATCOM subsystem is connected with the same bus of an HVDC subsystem receiving-end alternating-current system through a current conversion reactor (X1). According to the method, a substep starting manner is adopted, and during starting, the STATCOM subsystem is subjected to the composite control of a series-connection current limiting resistor and current decoupling and voltage feedforward control; and soft wart is adopted for the HVDC subsystem, and the setting value of a current regulator is gradually increased in a start process till the finish of the start. According to the invention, the HVDC system can be started to a rated running state under the condition that a receiving end system is an ultra-weak alternating-current system, the voltage property of the HVDC receiving-end alternating system is improved, and the HVDC system is prevented from failed commutation.
Owner:NORTH CHINA ELECTRIC POWER UNIV (BAODING)
Method for high-voltage direct-current transmission commutation failure prevention
InactiveCN103337870AAvoid commutation failureImprove defenseElectric power transfer ac networkFailure preventionHigh pressure
The invention provides a method for high-voltage direct-current transmission commutation failure prevention. The method comprises the following steps that: whether commutation failure caused by alternating current-side faults occurs or not is judged; a commutation failure prevention system outputs rectangular wave commands to a control protection system; and rectangular waves are subtracted from trigger angle commands in the control protection system, and a thyristor is triggered in advance. With the method adopted, commutation failure can be prevented when grounding faults or interphase short-circuit faults occur on an alternating current system, and the reduction amplitude of direct-current voltage and power transmission can be lowered after the faults occur.
Owner:NORTH CHINA ELECTRIC POWER UNIV (BAODING) +4
Method for double feed-in d.c. power transmission
ActiveCN101202445AImprove operational reliabilityReduce commutation failureElectric power transfer ac networkElectric power transmissionEngineering
The invention provides a dual feed-in DC transmission method, belonging to the distribution technical field. The invention is used for solving the operation reliability of the high-voltage DC transmission. The technical proposal is that an HVDC subsystem and a VSC-HVDC subsystem are connected on the same generatrix of a transmission AC system in parallel or respectively connected with two substations which are very closely connected with each other electrically; the HVDC subsystem consists of an AC system S1 at a sending end, a system resistance Zs1, a converter transformer Ts1, an HVDC converter and a transmission line DC1, and a converter transformer (Tr1); the VSC-HVDC subsystem consists of an AC system S2 at the sending end, a system resistance Zs2, a converter transformer Ts, a VSC-HVDC converter and a transmission line DC2, and a converter transformer (Tr2). Compared with the existing HVDC system, the invention can effectively reduce the possibility that steering failure occurs to the HVDC sub-system inverter, and improves the operation reliability of the HVDC subsystem.
Owner:NORTH CHINA ELECTRIC POWER UNIV (BAODING)
Multiple freedom degree dynamic control method for inverse transform bridge phase shifting advance angle of stationary frequency conversion starter
ActiveCN101359875AAvoid commutation failureImprove power factorAc-ac conversionFrequency changerTerminal voltage
Disclosed is a multi-degree-of-freedom dynamic control method of an inverter bridge advance commutation angle of a static frequency converter starter, comprising the steps of: the detection of motor operating frequency, main circuit direct current of a static frequency converter, terminal voltage, and the calculation of the inverter bridge advance commutation angle, Beta=cos<-1>(cos(360f(t(off)+t0))-(square root 2X(C)I(d) / U))+Xi. The control method enables the inverter bridge advance commutation angle to carry on the dynamic control with the change of motor operating frequency, of main circuit direct current of the static frequency converter and of terminal voltage in the process of frequency conversion start, and causes a considerable reduction in the inverter bridge advance commutation angle while ensuring the constant of the arc extinguishing time of the inverter bridge commutation, so as to reduce the main circuit output direct current of the frequency converter and increase the power factor of the inverter bridge and the start efficiency of the static frequency converter starter.
Owner:STATE GRID ELECTRIC POWER RES INST +2
Control and monitor method of silicon controlled rectifier converter valve for extreme high voltage direct current power transmission
ActiveCN104038034AAvoid commutation failureImprove protectionIndividual semiconductor device testingPower conversion systemsSilicon-controlled rectifierControl signal
The invention discloses a control and monitor method of a silicon controlled rectifier converter valve for extreme high voltage direct current power transmission. The control and monitor method of the silicon controlled rectifier converter valve for the extreme high voltage direct current power transmission includes: monitoring work status of the silicon controlled rectifier converter valve through a silicon controlled rectifier high potential electronic unit TEU; reporting the work status back to a valve base electronic equipment cabinet VBE through a high voltage optical fiber; for triggering a control signal, sending light trigger pulse signals through the valve base electronic equipment cabinet VBE so as to control the silicon controlled rectifier converter valve; for performing monitor protection, initiatively generating trigger protection through the silicon controlled rectifier high potential electronic unit TEU. Single pulses are adopted in the light trigger pulse signals, and coding standard design of all the pulses adopts the single pulse mode, and therefore pulse coding is simple, the problems that a silicon controlled rectifier is always in a conducting state due to recognition incorrectness of a pulse sequence formed by a plurality of continuous pulses, and then inverting failure, protection failure in a reverse recovery period and the like are caused by the silicon controlled rectifier are solved, and the control and monitor method of the silicon controlled rectifier converter valve for the extreme high voltage direct current power transmission is high in timeliness and reliability.
Owner:CHINA XD ELECTRIC CO LTD
Method for prejudging phase change failure of converter valve
ActiveCN103543357AEasy to judgeAvoid commutation failureElectrical testingVoltage amplitudeSystem failure
The invention provides a method for prejudging phase change failure of a converter valve. The method includes the steps of calculating an inverter side alternating current voltage amplitude per unit value and a direct current per unit value, calculating a fire angle upper limit of the converter valve on the inverter side and prejudging whether phase change is failed. According to the method for prejudging the phase change failure of the converter valve, phase change failure caused by inverter side alternating current system failure or direct current system overloading and other common reasons can be accurately judged, and information is provided for preventing the phase change failure. Judgment can be carried out quickly, phase change failure judgment information can be obtained in 1ms after the failure occurs, and measures can be quickly taken to prevent the phase change failure. Judgment is accurate, the calculation method of the fire angle upper limit is obtained through theoretical deduction, and the phase change failure can be accurately judged through the method.
Owner:NORTH CHINA ELECTRIC POWER UNIV (BAODING) +3
Control method and device of multi-split air conditioning system
InactiveCN109798642AImprove the high and low pressure differenceAvoid commutation failureMechanical apparatusSpace heating and ventilation safety systemsFour-way valveHigh pressure
The invention provides a control method and device of a multi-split air conditioning system. The control method of the multi-split air conditioning system comprises the steps that four-way valve reversing requirements of the multi-split air conditioning system are obtained; high pressure and low pressure of the multi-split air conditioning system are obtained, wherein the high pressure is the pressure between an air outlet of a compressor and the air outlet ends of four-way valves of the multi-split air conditioning system, and the low pressure is the pressure between the air suction ends of the four-way valves and an air suction opening of the compressor; the pressure difference between the high pressure and the low pressure of the multi-split air conditioning system is calculated; and the running frequency of the compressor and the opening of throttling devices of the multi-split air conditioning system are subjected to a first-time adjustment and a second-time adjustment. Thus, through the first-time adjustment and the second-time adjustment to the running frequency of the compressor and the opening of throttling devices of the multi-split air conditioning system, the pressure difference between the high pressure and the low pressure of the multi-split air conditioning system is improved, and the reversing failure of the four-way valve in the multi-split air conditioning system is avoided.
Owner:GD MIDEA HEATING & VENTILATING EQUIP CO LTD +1
Comprehensive judgment method for semi-main wiring transformer substation dead zone fault
ActiveCN106786426AAvoid commutation failureIncrease safety and stability marginEmergency protective circuit arrangementsFault location by conductor typesElectric power systemTransformer
The invention discloses a comprehensive judgment method for a semi-main wiring transformer substation dead zone fault. The method comprises the steps that the three-phase current of each breaker of a whole transformer substation and three-phase voltage on each string are collected in real time; each bus protection, line protection and transformation protection tripping signal in the whole transformer substation is sampled; the three-phase current of the breakers, the three-phase voltage and zero sequence voltage on each string and interphase impedance of the breakers are calculated, a fault area is selected according to the sampled protection tripping signals, and comprehensive fault locating is carried out through the breaker current magnitude and waveform characteristics obtained after protection tripping and the voltage and impedance magnitude. According to the comprehensive judgment method utilizing full substation information of the transformer substation, a breaker unit suffering from the dead zone fault of the transformer substation is selected, high safety is achieved, the acting speed is high, the result can be applied to station domain breaker dead zone protection judgment, the fault clearing time of breaker dead zone protection can be greatly shortened, and the safety of a large power grid electric system is improved.
Owner:BEIJING SIFANG JIBAO AUTOMATION
Extra-high-voltage DC multi-infeed system commutation failure prevention and control method and system
PendingCN110797898AAvoid commutation failureElectric power transfer ac networkFailure preventionControl engineering
The invention relates to an extra-high-voltage DC multi-infeed system commutation failure prevention and control method and system. After an AC system breaks down, commutation failure prevention and control of an inverter valve group which is close to an AC fault point in electrical distance is greatly triggered in advance, and therefore, commutation failure of an inverter valve group which is faraway from the AC fault point in electrical distance is possibly caused. According to the application, a coordinated control mode is adopted, and commutation failure prevention coordinated control output of the inverter valve group in the area near the fault is adaptively adjusted according to the turn-off angle drop value of the inverter valve group in the area away from the fault, so that commutation failure of the inverter valve group in the area away from the fault is avoided.
Owner:STATE GRID HENAN ELECTRIC POWER ELECTRIC POWER SCI RES INST +2
Energy-storage type static synchronous compensation device and direct-current transmission commutation failure suppression method
InactiveCN109245147AAvoid commutation failureImprove safety and reliabilityFlexible AC transmissionElectric power transfer ac networkAC powerDc converter
The invention discloses an energy storage type static synchronous compensation device and a direct-current transmission commutation failure suppression method, The large-capacity energy-storage type static synchronous compensation device is composed of a plurality of energy-storage type static synchronous compensators which are connected in parallel. The energy-storage type static synchronous compensator (1) comprises an energy storage unit, a DC / DC converter, a capacitor and a voltage source converter. The energy storage static synchronous compensator is connected to the AC bus of the receiving end converter station of the UHVDC transmission system through a transformer. The inductor is serially connected to the AC bus bar of the energy storage type static synchronous compensation deviceand the receiving end converter station, The large-capacity energy storage type static synchronous compensation device operates in a voltage source mode, and can provide sufficient voltage support forthe receiving end AC bus bar of the receiving end converter station to ensure normal commutation, thereby restraining commutation failure caused by fault of the receiving end AC power network and preventing cascading failure caused by commutation failure to the UHVDC transmission system.
Owner:HUNAN UNIV
Secondary commutation failure determination method and system
ActiveCN108964110AHigh precisionAvoid commutation failureElectric power transfer ac networkFailure preventionReliability engineering
The invention discloses a secondary commutation failure determination method and system; the method comprises the following steps: using an equivalent fault method to obtain an extinction angle of each inversion station after the fault occurs; determining the minimum extinction angle according to the extinction angle of each inversion station, the inversion station with the minimum extinction angle, and a commutation bus on which the inversion station with the minimum extinction angle is located; determining whether the minimum extinction angle is smaller than or equal to a critical extinctionangle or not; if yes, determining the inversion station with the minimum extinction angle has a commutation failure, and obtaining the voltage of the commutation bus on which the inversion station with the minimum extinction angle is located; determining whether the voltage of the commutation bus on which the inversion station with the minimum extinction angle is located is smaller than or equalto a commutation bus voltage critical value or not; if not, determining the commutation failure type of the inversion station with the minimum extinction angle is the secondary commutation failure. The method and system can determine the commutation failure type as the secondary commutation failure, thus improving the commutation failure prevention effect.
Owner:TSINGHUA UNIV +1
Hybrid converter topological structure based on controllable turning off and control method of hybrid converter topological structure
PendingCN112311274AFast recovery timeAuxiliary commutationEfficient power electronics conversionElectric power transfer ac networkPhase currentsTransformer
The invention relates to a hybrid converter topological structure based on controllable turning off and a control method of the hybrid converter topological structure. The topological structure is a three-phase six-bridge-arm circuit; the three-phase six-bridge-arm circuit is connected to an alternating current power grid through a converter transformer; the upper bridge arm and the lower bridge arm of each phase of the three-phase six-bridge-arm circuit are respectively composed of valve modules. Each valve module is composed of a main branch and an auxiliary valve which is connected with themain branch in parallel and has forward current controllable turn-off and forward and reverse voltage blocking capacities. Each main branch is composed of thyristor valves which are connected in series, and a turn-off valve which has forward current controllable turn-off and forward voltage blocking capabilities. According to the hybrid converter topological structure provided by the invention, the current turn-off characteristic of a turn-off device is fully utilized; commutation current can be quickly transferred; the commutation voltage time area of the thyristor valves is flexibly controlled; and it can be ensured that the thyristor valves have enough reverse recovery time to be reliably turned off; and meanwhile, the problem of commutation failure of a direct-current system can be fundamentally solved by utilizing the turn-off valves to assist commutation.
Owner:GLOBAL ENERGY INTERCONNECTION RES INST CO LTD +1
Current source type phase modulator variable frequency starting commutation lead angle piecewise control method
ActiveCN109995275AImprove start-up efficiencyReduce startup timeReactive power adjustment/elimination/compensationReactive power compensationStart up timeEngineering
The invention provides a current source type phase modulator variable frequency starting commutation lead angle piecewise control method which comprises the concrete steps that a commutation lead angle of 30 degrees is used when a current source type phase modulator is started; commutation failure is judged through a detection system, the commutation lead angle of 30 degrees is maintained if the commutation failure is not detected, and the closest thyristor seamless switching time point t0 is found when the commutation failure is detected; and the commutation lead angle is switched to 60 degrees. The method is simple and convenient in practical application without redundant algorithm control; the problem of thyristor commutation failure can be effectively avoided, the starting efficiency of the phase modulator can be improved, the starting time can be shortened, the whole control process only needs one time of switching of the commutation lead angle and the redundancy of thyristor operation times can be avoided; and commutation lead angle piecewise control is used so as to have high practical engineering application value.
Owner:JIANGSU FRONTIER ELECTRIC TECH +4
Commutation failure prediction control method and device based on direct-current (DC) electric quantity
ActiveCN108599225AQuick responseImprove accuracyElectric power transfer ac networkDc currentHigh pressure
The invention discloses a commutation failure prediction control method and device based on a direct-current (DC) electric quantity, which is used to prevent the phenomenon that in a high-voltage or ultrahigh-voltage DC system, failure of a DC side of some pole causes commutation failure of a healthy pole through mutual inductance between the two poles. The method is characterized in that a suddenincrement (or sudden increments) of an absolute value (or absolute values) of the DC voltage and / or the DC current of a current pole in some time window is / are detected in a real-time manner; and when the sudden increment(s) of the absolute value(s) of the DC voltage and / or the DC current exceeds / exceed a preset threshold (or preset thresholds), an extinction angle of an inversion side converterof the current pole is enlarged through a DC control system, so that the commutation failure of the current pole is prevented. The method provided by the invention is applicable for prediction and prevention of the commutation failure of the healthy pole caused by the failure of the DC side of the other pole, and has the advantages of high response speed and high action accuracy.
Owner:NR ELECTRIC CO LTD +2
High-voltage direct-current commutation failure control method and device for quickly detecting alternating-current fault
ActiveCN112952824AAvoid commutation failureSolve commutation failureElectric power transfer ac networkContigency dealing ac circuit arrangementsSingle phaseThree-phase electric power
The invention relates to a high-voltage direct-current commutation failure control method, device and equipment for quickly detecting an alternating-current fault, which are applied to a high-voltage direct-current power transmission system. According to the invention, a single-phase fault occurrence phase, namely a fault phase, is determined according to a three-phase voltage of an alternating-current side bus of a high-voltage direct-current power transmission system, the maximum phase offset between a phase voltage and a phase positive sequence voltage at the moment is solved according to the fault phase, a commutation angle with the maximum offset and a synchronous phase angle output by the phase-locked loop of the high-voltage direct-current power transmission system are added to obtain a corrected synchronous phase angle, and the trigger angle of the fault phase is adjusted or corrected by correcting the synchronous phase angle to achieve the effect of correcting the actual trigger angle; and compared with the prior art, the high-voltage direct-current commutation failure control method for quickly detecting the alternating-current fault has the advantages that the fault phase can be quickly judged, a commutation failure result caused by an output error of a phase-locked loop of the high-voltage direct-current power transmission system in an alternating-current fault period is effectively avoided, and the problem of commutation failure of an existing high-voltage direct-current power transmission system is solved.
Owner:CHINA SOUTH POWER GRID ELECTRIC POWER RES INST +1
A hybrid direct current transmission converter and direct current transmission device
ActiveCN104578130BAvoid commutation failureInhibit injectionPower network operation systems integrationElectric power transfer ac networkThyratronAlternating current
The invention discloses a hybrid direct-current transmission converter. The hybrid direct-current transmission converter is provided with four topological structures which are series connection circuits formed by combining anodes and cathodes of current source type valve group units and positive electrodes and negative electrodes of voltage source type valve group units in different modes. Each current source type valve group unit only comprises a current source type valve group or comprises a current source type valve group and a bypass switch or comprises a current source type valve group, a bypass switch and a disconnecting link assembly. Each voltage source type valve group unit only comprises a voltage source type valve group or comprises a voltage source type valve group and a bypass circuit or comprises a voltage source type valve group, a bypass circuit and a disconnecting link assembly. A direct-current transmission device composed of the hybrid direct-current transmission converter effectively solves the problem of commutation failures of a direct-current transmission system based on thyristors and the problem of direct-current faults of a direct-current transmission system based on a voltage source converter, and has the advantages that loss is low, a reactive compensation device is not needed or a small number of reactive compensation devices are needed, and the direct-current transmission device can be connected into a passive alternating-current system and has the inverse power output function.
Owner:NR ELECTRIC CO LTD +1
Direct-current transmission regulating method with multiple current transformers
InactiveCN101273518AAvoid HierarchyAvoid Regulatory SeparationElectric power transfer ac networkAc-dc conversionDc currentPower grid
The invention relates to a method for controlling at least three power converters (2), which can be controlled by a rectifier (6) or an inverter (8) and are connected together by a direct current network (7), in the region of power distribution and power transmission. The aim of the invention is to provide a method which has a simple structure and also works in a reliable manner. As a result, a measuring direct current voltage (Udc_l, ... Udc_rr; Udc_il ... Udc_ii) and a measuring direct current (Idc__rl, ... Idc_rr; Idc__il, ... Idc_ii) are measured on each power converter and respectively, transmitted to the respective rectifier control (11) and / or inverter control (12), and a rectifier desired direct power and / or inverter desired direct power (Pdco_rl, ... Pdco-rr,- Pdco_il, ... Pdco_ii) is determined for each power converter. The total of all desired direct powers (Pdco_rl, ...; Pdco_rr; Pdco-il, ... Pdco_ii) is equal to zero, and a desired direct voltage (¿˜dco_rl, ... Udco_rr; Udco__il, ... Udco_ii) is determined from each desired direct power, the smallest inverter desired direct voltage (Udco_il, ... Udco_ii) of all connected inverters (8) is fixed as minimal direct voltage (Udco) by means of a minimal direct voltage and the desired direct voltage, a desired direct current (Idco_rl; ... Idco_rr; Idco_il, ... Idco_ii) is formed from the minimal voltage (Udco) and the measuring direct voltage, a differential direct voltage (du_rl, ... du_rr, du_il, ... du_ii) is formed from the minimal voltage (Udco) and the differential direct current (di_rl; ... di_rr; di_il, ... di_ii) is formed from the desired direct current and the measuring direct current.
Owner:SIEMENS AG
Line-commutated converter control system and method
ActiveCN108701998AImprove reliabilityImprove stabilityElectric power transfer ac networkControl systemDc current
It provides a control system for LCC of an HVDC system and a control method therefor. The control system includes: a first measurement unit (20) being configured to provide a current magnitude measurement indicative of a magnitude of DC current of the HVDC system; and a controller (21) being configured to increase a first extinction angle at which the controlled LCC operates to a second extinctionangle in response to that the current magnitude measurement exceeds a current reference level in order to avoid commutation failure of the controlled LCC. By using the solutions according to the HVDCsystem with increase of the extinction angle of the LCC, it is possible to decrease the probability of commutation failures caused by a rapid rise of the DC current of the HVDC system. The overall ACand DC power system reliability and stability are improved.
Owner:HITACHI ENERGY SWITZERLAND AG
Commutation failure prevention and control optimization method and system based on SVM-PSO
ActiveCN111327082AExcellent reactive power outputExcellent reactive power compensation capacityElectric power transfer ac networkSingle network parallel feeding arrangementsFailure preventionAlgorithm
The invention discloses a commutation failure prevention and control optimization method and system based on SVM-PSO, and the method comprises: taking the minimum reactive control quantity and the minimum number of fault nodes triggering commutation failure as a target function, considering the steady-state safety constraint, and building a multi-target optimization function for optimizing the reactive output and reactive compensation capacity of a generator; and solving the multi-objective optimization function by adopting an improved particle swarm algorithm with parameter adaptability to obtain optimal reactive output and reactive compensation capacity of the generator. The method has the beneficial effects that the support vector machine agent model is constructed to evaluate the commutation result, so that the particle adaptation value is quickly solved.
Owner:STATE GRID SHANDONG ELECTRIC POWER +2
Active commutation hybrid converter topological structure and control method thereof
PendingCN112803796AIncrease time areaAvoid commutation failureAc-dc conversionElectric power transfer ac networkPower gridHemt circuits
The invention discloses an active commutation hybrid converter topological structure and a control method thereof. The active commutation hybrid converter topological structure comprises a three-phase six-bridge arm circuit, an upper bridge arm auxiliary valve, a lower bridge arm auxiliary valve, a controllable switch module and a selection unit, wherein each phase of bridge arm circuit of the three-phase six-bridge arm circuit comprises an upper bridge arm and a lower bridge arm, and the upper bridge arm or the lower bridge arm is provided with a thyristor valve; the first end of the upper bridge arm auxiliary valve is connected with the cathode end of the thyristor valve of each phase of each upper bridge arm; the first end of the lower bridge arm auxiliary valve is connected with the anode end of the thyristor valve of each phase of each lower bridge arm; the first end of the controllable switch module is connected with the second end of the upper bridge arm auxiliary valve and the second end of the lower bridge arm auxiliary valve; the selection unit comprises two connecting ends and at least two selection ends, and the connecting ends are connected with the second end of the controllable switch module; and the first selection end is connected with the anode end of the thyristor valve of each upper bridge arm, and the second selection end is connected with the cathode end of the thyristor valve of each lower bridge arm. By implementing the active commutation hybrid converter topological structure and the control method, the occurrence of commutation failure is avoided, and the stability and safety of power grid operation are ensured.
Owner:GLOBAL ENERGY INTERCONNECTION RES INST CO LTD
Extra-high-voltage converter transformer with filtering function
ActiveCN112259336AWith filtering effectAvoid commutation failureTransformers/inductances coolingTransformers/inductances coils/windings/connectionsTransformerHigh-voltage direct current
The invention provides an extra-high-voltage converter transformer with a filtering function. A making method of the extra-high-voltage converter transformer with the filtering function comprises thefollowing steps that S1, the converter transformer of an extra-high-voltage direct-current power transmission system serves as an object, and the magnetic circuit saturation condition and the harmoniccirculation condition of the converter transformer are taken into consideration, wherein a circuit magnetic circuit analysis structure of a single iron core column is included; and S2, the magnetic circuit distribution and a circuit structure of the converter transformer are taken into consideration, and a four-winding type converter transformer electromagnetic coupling circuit and an electromagnetic coupling circuit equivalent circuit model according to an extra-high voltage direct current power transmission operation scene. The extra-high-voltage converter transformer with the filtering function is suitable for an extra-high-voltage direct-current power transmission system, and has a harmonic filtering function while having voltage matching and electrical isolation functions of a commonconverter transformer, so the grid-side harmonic and reactive burdens of an existing extra-high-voltage direct-current power transmission project converter transformer are reduced, and the reliability of the extra-high-voltage direct-current power transmission project is improved; and thus, the investment of a grid-side alternating-current filter is reduced.
Owner:陈生栋
Hybrid converter topological structure and control method thereof
PendingCN112803815ASafe and stable operationRealize auxiliary commutation functionElectric power transfer ac networkAc-dc conversionPower gridControl engineering
Owner:GLOBAL ENERGY INTERCONNECTION RES INST CO LTD
HVDC convert and control method thereof
ActiveCN109167528AFault Ride ThroughAvoid commutation failureAc-dc conversionDc-dc conversionControl powerComputer module
The invention relates to the technical field of power electronics, in particular to a HVDC converter and a control method thereof, aiming at solving the technical problem of how to overcome the commutation failure and fault crossing failure of the converter. For this purpose, the invention provides a high-voltage direct-current transmission converter and a control method thereof. Specifically, theHVDC converter mainly comprises a first converter circuit formed by cascading a plurality of power sub-modules, The first converter circuit can output a multi-level AC pulse voltage, thereby drivingthe half-controlled power electronic device in the second converter circuit to be turned on or off actively or passively, and realizing fault crossing when a fault occurs on the high-voltage AC voltage source side. In this process, the commutation failure of HVDC converter can be effectively avoided without considering the voltage phase of HVAC voltage source side.
Owner:INST OF ELECTRICAL ENG CHINESE ACAD OF SCI
Control system and method for a line-commutated converter for a high voltage direct current system
ActiveCN108701998BImprove reliabilityImprove stabilityElectric power transfer ac networkControl systemDc current
The present invention provides a control system and a control method for the LCC of the HVDC system. The control system includes: a first measurement unit (20) configured to provide a current amount measurement indicative of the DC current flow of the HVDC system; and a controller (21) configured to respond to When the measured value of the current amount exceeds the current reference level, the first arc extinguishing angle during the operation of the controlled LCC is increased to the second arc extinguishing angle, so as to avoid the commutation failure of the controlled LCC. By using the solution of the HVDC system, as the quenching angle of the LCC increases, the probability of commutation failure caused by the rapid rise of the DC current of the HVDC system can be reduced. The reliability and stability of the entire AC and DC power system are improved.
Owner:HITACHI ENERGY SWITZERLAND AG
Control Method of HVDC Converter
ActiveCN109167528BFault Ride ThroughAvoid commutation failureAc-dc conversionDc-dc conversionControl powerHemt circuits
The invention relates to the technical field of power electronics, in particular to a control method for a high-voltage direct current transmission converter, and aims to solve the technical problems of how to overcome commutation failure and fault ride-through failure of the converter. For this purpose, the present invention provides a high-voltage direct current transmission converter and a control method thereof. Specifically, the high-voltage direct current transmission converter mainly includes a first commutation circuit composed of multiple power sub-modules cascaded, and the first commutation circuit can output multi-level AC pulse voltage, thereby driving the second commutation circuit The semi-controlled power electronic devices in the circuit are actively turned on or passively turned off, and realize fault ride-through when a fault occurs on the high-voltage AC voltage source side. In this process, it is not necessary to consider the voltage phase of the high-voltage AC voltage source side, so that the commutation failure of the HVDC converter can be effectively avoided.
Owner:INST OF ELECTRICAL ENG CHINESE ACAD OF SCI
A method and system for judging secondary commutation failure
ActiveCN108964110BHigh precisionAvoid commutation failureElectric power transfer ac networkFailure preventionComputational physics
The invention discloses a secondary commutation failure determination method and system; the method comprises the following steps: using an equivalent fault method to obtain an extinction angle of each inversion station after the fault occurs; determining the minimum extinction angle according to the extinction angle of each inversion station, the inversion station with the minimum extinction angle, and a commutation bus on which the inversion station with the minimum extinction angle is located; determining whether the minimum extinction angle is smaller than or equal to a critical extinctionangle or not; if yes, determining the inversion station with the minimum extinction angle has a commutation failure, and obtaining the voltage of the commutation bus on which the inversion station with the minimum extinction angle is located; determining whether the voltage of the commutation bus on which the inversion station with the minimum extinction angle is located is smaller than or equalto a commutation bus voltage critical value or not; if not, determining the commutation failure type of the inversion station with the minimum extinction angle is the secondary commutation failure. The method and system can determine the commutation failure type as the secondary commutation failure, thus improving the commutation failure prevention effect.
Owner:TSINGHUA UNIV +1
Power conversion device
ActiveCN103748777AReduce the number of timesAvoid commutation failureAc-dc conversionAc-ac conversionAC powerSwitching time
A power conversion device comprises a conversion circuit having multiple-pair switching elements connected to each phase and converting an input AC power to an AC power. A first switching time is calculated that is the time required for: turning on the switching element of an upper arm circuit in one of the phases; turning off the switching elements of the upper arm circuit in the other phases; turning on at least one switching element of a lower arm circuit in the other phases; and turning off the switching element of the lower arm circuit in the one of the phases. A second switching time is also calculated that is the time required for turning on the switching element in the one of the phases and turning off the switching elements in the other phases. When making transition from the first switching time to the second switching time, among th e switching elements in the on-state, a switching element of either the upper arm circuit or the lower arm circuit is turned off and a switching element of the other arm circuit is maintained to be in the on-state.
Owner:NISSAN MOTOR CO LTD +1
Four-way reversing valve and heat exchange system comprising same
PendingCN109405342AAvoid commutation failureReduce frictionOperating means/releasing devices for valvesMultiple way valvesLinear actuatorEngineering
The invention discloses a four-way reversing valve and a heat exchange system comprising the same. The four-way reversing valve comprises a valve body; a valve element is arranged inside the valve body; an air suction pipe opening, an air exhaust pipe opening, a first connecting pipe opening and a second connecting pipe opening are formed in the valve body; the valve element can move along an inner cavity of the valve body; a first cavity is formed by the left side of the valve body and the valve element; a second cavity is formed by the right side of the valve body and the valve element; a connecting rod is horizontally arranged on one side, connected with the first cavity, of the valve element; one end of the connecting rod is rotationally connected with an inner crank; one end of the inner crank is rotationally connected with a control shaft; a linear actuator is arranged in the position, close to the first connecting pipe opening, of the outer side of the valve body; an outer crankis rotationally connected to a front-end extending shaft of the linear actuator; and the control shaft penetrates through the valve body outwards to be rotationally connected with the outer crank. Bythe aid of the four-way reversing valve and the heat exchange system comprising the same, the problem of ineffective reversing caused by the fact that valve elements are relatively heavy and are relatively difficult to push and high-pressure gas colludes in the prior art is solved.
Owner:WUXI VOCATIONAL & TECHN COLLEGE
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