The converter valve Tests at Steady State device and method of bias voltage is undertaken using electric capacityTechnical field
The present invention relates to flexible DC power transmission and applied power electronics technical field, biasing is more particularly to undertaken using electric capacityThe converter valve Tests at Steady State device and method of voltage.
Background technology
Flexible direct current power transmission system based on MMC voltage source converters, which has to passive system or weak AC system, to be suppliedElectric, active and idle quick independent control, it is readily configured multiterminal network and the excellent properties such as environment-friendly, and MMC-HVDC systemsThe conveying voltage harmonic content of system is extremely low, without being reconfigured at extra wave filter so that the flexible DC power transmission based on MMC is defeatedElectrical domain has a wide range of applications.And MMC-HVDC core component power unit module is whole flexible DC power transmission changesThe minimum unit of valve is flowed, power unit module composition valve section is made up of 6 bridge arms of converter valve valve section.
The reliability of converter valve directly determines the reliability of flexible direct current power transmission system.It is defeated in flexible direct current in order to ensureIn the various operating modes of electric system, converter valve can reliability service, IEC standard define to converter valve section carry out pattern examinationTest, wherein containing Tests at Steady State.This is indispensable important step in flexible DC power transmission engineering design link, isThe important guarantee that whole soft lineal system later stage safety and stability is persistently run.
According to the requirement of actual operating mode and the regulation of IEC standard, in process of the test, the voltage one at converter valve two endsAs include DC voltage component and alternating current voltage component, under typical design, DC voltage component is equivalent to the specified electricity of valve sectionThe half of pressure, and the amplitude of alternating current voltage component is approximately equal to the half of valve section rated voltage.In order to be powered to valve section, produce simultaneouslyRequired DC voltage component, presently disclosed all methods depend on high-voltage DC power supply or extra converter valve, hence it is evident thatAdd experimentation cost.
A kind of Publication No. CN105372586A Chinese patent " flexible DC power transmission voltage source converter valve operating testMethod in device " needs extra HVDC rectifier power source and an extra complementary energy bridge arm, hence it is evident that increase experiment dressThe cost put, and because system is asymmetric, control is complicated.
Publication No. CN106546852A Chinese patent " a kind of MMC converter valves Tests at Steady State circuit and its controlMethod ", then need the soft straight bridge arm of extra two to carry out complementary energy, be powered while being also required to HVDC rectifier power source, brightIt is aobvious to increase experimentation cost.
The content of the invention
In order to overcome the deficiencies in the prior art, the present invention provides the converter valve stable state that a kind of use electric capacity undertakes bias voltageOperating test device and method, make full use of the electric capacity of series connection in the loop to undertake the DC voltage component between converter valve end,Pilot system is charged by common transformer, complementary energy, it is not necessary to configuring direct current power supply, it is not necessary to extra complementary energy valve.Required transformer, simply can be realized, major loop with a low power single-phase transformer realization, or a pressure regulatorIt is simple and reliable.
In order to achieve the above object, the present invention is realized using following technical scheme：
The converter valve Tests at Steady State device of bias voltage, including test product valve 1, test product valve 2, electric capacity are undertaken using electric capacityCL, transformer T1, loop current suppression reactance L01, switch K01 and AC-testing supply S0.
Described test product valve 1 is connected and is grounded with the one end of test product valve 2, and other end is connected on loop current suppression reactance L01 respectivelyBoth sides, after transformer T1 vice-side winding is connected with electric capacity CL, one end ground connection, other end connects loop current suppression reactance L01'sAny one end, transformer T1 primary side winding after switch K01 concatenations with AC-testing supply S0 with being connected.
Described transformer T1 can use pressure regulator, by the slow pressure regulation of pressure regulator to experiment electricity in process of the testCharged on road.
Charging resistor R, and the also parallel connection on charging resistor R can also be in series with the middle of transformer T1 and switch K01There is by-pass switch K02, hookup is charged by charging resistor and by-pass switch in process of the test.
Two test product valve balanced arrangements can also be made using two loop current suppression reactance L01 and L02, connected mode is：ExaminationProduct valve 1 is connected and is grounded with the one end of test product valve 2, and other end is connected with loop current suppression reactance L01, L02, transformer T1 secondaryAfter winding is connected with electric capacity CL, one end ground connection, other end is connected on loop current suppression reactance L01, L02 midpoint.
The test method of the converter valve Tests at Steady State device of bias voltage is undertaken using electric capacity, including：
(1), it is necessary to be charged to them when the cell capacitance voltage in test product valve is not set up also, there are two kindsCharging method is optional：Charged and charged using charging resistor R and charging resistor by-pass switch K02 using pressure regulator T1Two kinds of charging methods；
(2) AC-testing supply is used, the method that alternately charging is carried out to electric capacity and test product valve in charging process；
(3) method that the DC voltage component between test product valve end is undertaken using electric capacity CL：Because external connection exchange becomesDepressor, its both end voltage is industrial-frequency alternating current, therefore, is connected on the electric capacity of transformer secondary by the direct current between undertaking test product valve endComponent of voltage, and AC transformer produces the alternating current voltage component between test product valve end；
(4), it is necessary to when adjusting DC voltage component between the end of test product valve, slowly adjust test product valve in process of the testModulated signal, it is ensured that DC voltage component between its end is slowly varying, and the voltage on such series capacitance CL can follow examinationVoltage DC component between the end of product valve, it is to avoid shoved in Transformer Winding because voltage difference is produced, therefore in test product valve direct currentIn component of voltage change procedure, the voltage on electric capacity CL also changes simultaneously, keeps test product valve and the total voltage on electric capacity CL and electricityThe source balance of voltage, so as to also achieve complementary energy of the AC power to test product valve；
(5) in process of the test, the modulated signal of control test product valve 1 and test product valve 2 so that the electric current in test product valve is met willAsk；Control the modulated signal of complementary energy valve so that the capacitor voltage balance in complementary energy valve, test product valve 1, test product valve 2, and meet experimentIt is required that.
Described is using the pressure regulator T1 methods charged：
Step 1: when starting, pressure regulator T1 being transferred to and is output as no-voltage, K01 is closed；
Step 2: then slow rise pressure regulator T1 output voltages, due to test product valve, series capacitance CL, transformer secondaryWinding is to be connected in series, if test product valve is made up of half-bridge cells, and test product valve is charged in the positive half-wave of AC power, and is exchangedThe negative half-wave of power supply charges to series capacitance CL；If test product valve is made up of full bridge unit, the positive and negative half-wave of AC power, electric currentAll unit is charged；If test product valve is made up of half-bridge cells and full bridge unit mixing, in the positive half-wave of AC power, electricityStream charges to all units, and the negative half-wave of AC power, and electric current charges to full bridge unit therein and series capacitance；
Step 3: waiting pressure regulator to rise to assigned voltage, charging terminates, the bridge arm capacitance voltage on test product valve at this momentWith the crest voltage equal to AC power plus the voltage on series capacitance CL, experiment can be started.
Described is using charging resistor R and charging resistor by-pass switch the K02 method charged：
Step 1: closing K01 first, start to test product valve and series capacitance CL chargings；
Step 2: because test product valve, series capacitance CL, transformer secondary winding are to be connected in series, if test product valve is by halfBridge unit is constituted, and test product valve is charged in the positive half-wave of AC power, and the negative half-wave of AC power charges to series capacitance CL；If test product valve is made up of full bridge unit, the positive and negative half-wave of AC power, electric current all charges to unit；If test product valve byHalf-bridge cells and full bridge unit mixing composition, in the positive half-wave of AC power, electric current charges to all units, and AC powerNegative half-wave, electric current charges to full bridge unit therein and series capacitance；
Step 3: waiting after end unit voltage stabilization to be charged, closure charging resistor by-pass switch K01；At this moment test productBridge arm capacitance voltage on valve and equal to AC power crest voltage plus the voltage on series capacitance CL, examination can be startedTest.
Described test method also includes following methods：In process of the test, test product valve 1, test product valve 2 and loop current suppression electricityRequired test current has been flowed through in anti-L01；The generation of test current is different with the debugging signal of test product valve 2 by test product valve 1Produce；Under typical test situation, the modulating wave of test product valve 1 and test product valve 2 is all given as sinusoidal signal, both amplitudes, frequencyIt is equal, differ a small angle；Therefore, on test product valve 1 and the loop current suppression reactor of the centre of test product valve 2, both will be bornThe difference of voltage, thus produce the sinusoidal circulation of an identical frequency；And capacitance voltage difference small between two test product valves willCause the DC component on loop current suppression reactor；Sinusoidal circulation and DC component have synthesized required test current.
Compared with prior art, the beneficial effects of the invention are as follows：
1st, use electric capacity of the invention undertakes the converter valve Tests at Steady State device and method of bias voltage, makes full use ofSeries connection electric capacity in the loop undertakes the DC voltage component between converter valve end, by common transformer pilot system is carried outCharging, complementary energy, it is not necessary to configuring direct current power supply, it is not necessary to extra complementary energy valve.Required transformer, can be simply small with oneThe single-phase transformer of power realized, or a pressure regulator is realized, major loop is simple and reliable.
2nd, use electric capacity of the invention undertakes the converter valve Tests at Steady State device and method of bias voltage, can useCharged using charging resistor R and charging resistor by-pass switch K02 and carry out two kinds of charging methods of charging using pressure regulator T1,Stable regulation can be carried out to charging current in charging process using pressure regulator charging.
3rd, a kind of converter valve Tests at Steady State device and method of use AC-testing supply of the invention, was being tested, it is necessary to when adjusting DC voltage component between the end of test product valve in journey, the modulated signal of slow adjustment test product valve, it is ensured that between its endDC voltage component is slowly varying, and the voltage on such series capacitance CL can follow voltage DC point between the end of test product valveAmount, it is to avoid shoved in Transformer Winding because voltage difference is produced, therefore in test product valve DC voltage component change procedure, electricityHold the voltage on CL also simultaneously to change, keep test product valve to be balanced with the total voltage on electric capacity CL with supply voltage, so as to also realizeComplementary energy of the AC power to test product valve.
Brief description of the drawings
Fig. 1 is the converter valve Tests at Steady State device topology diagram of the present invention；
Fig. 2 is that the use pressure regulator of the present invention controls the operating test device topology diagram of charging process；
Fig. 3 is that the use charging resistor of the present invention controls the operating test device topology diagram of charging process；
Fig. 4 is the full symmetric operating test device topology diagram of two test product valves of the invention；
Fig. 5 is the half-bridge power unit modular circuit schematic diagram of the present invention；
Fig. 6 is the full bridge power unit module circuit theory diagrams of the present invention.
Embodiment
The embodiment provided below in conjunction with accompanying drawing the present invention is described in detail.
As shown in figure 1, the converter valve Tests at Steady State device of bias voltage is undertaken using electric capacity, including test product valve 1, examinationProduct valve 2, electric capacity CL, transformer T1, loop current suppression reactance L01, switch K01 and AC-testing supply S0.
Described test product valve 1 is connected and is grounded with the one end of test product valve 2, and other end is connected on loop current suppression reactance L01 respectivelyBoth sides, after transformer T1 vice-side winding is connected with electric capacity CL, one end ground connection, other end connects loop current suppression reactance L01'sAny one end, transformer T1 primary side winding after switch K01 concatenations with AC-testing supply S0 with being connected.
As shown in Fig. 2 described transformer T1 can use pressure regulator, pass through the slow tune of pressure regulator in process of the testPressure charges to hookup.
As shown in figure 3, charging resistor R can also be in series with the middle of transformer T1 and switch K01, and in charging resistorBy-pass switch K02 is also parallel with R, hookup is charged by charging resistor and by-pass switch in process of the test.
As shown in figure 4, two test product valve balanced arrangements can also be made using two loop current suppression reactance L01 and L02, connectMode is：Test product valve 1 is connected and is grounded with the one end of test product valve 2, and other end is connected with loop current suppression reactance L01, L02, transformationAfter device T1 vice-side winding is connected with electric capacity CL, one end ground connection, other end is connected to loop current suppression reactance L01, L02 midpointOn.
The test product valve section of the experimental rig is formed by the cascade of one or more power unit modules, wherein each power listFirst submodule can be half-bridge cells submodule, as shown in Figure 5 or full bridge unit submodule, as shown in Figure 6.Half-bridgeUnit submodule includes the composition such as two IGBT and diode, capacitor, discharge resistance, power unit module master control borad；EntirelyBridge unit submodule includes the composition such as four IGBT and diode, capacitor, discharge resistance, power unit module master control borad.By controlling the turn-on and turn-off of IGBT inside triggering submodule to control the input of power cell submodule and cut out, Neng GourangVoltage needed for the output of valve end.
The test method of the converter valve Tests at Steady State device of bias voltage is undertaken using electric capacity, including：
(1), it is necessary to be charged to them when the cell capacitance voltage in test product valve is not set up also, there are two kindsCharging method is optional：Charged and charged using charging resistor R and charging resistor by-pass switch K02 using pressure regulator T1Two kinds of charging methods；
(2) AC-testing supply is used, the method that alternately charging is carried out to electric capacity and test product valve in charging process；
(3) method that the DC voltage component between test product valve end is undertaken using electric capacity CL：Because external connection exchange becomesDepressor, its both end voltage is industrial-frequency alternating current, therefore, is connected on the electric capacity of transformer secondary by the direct current between undertaking test product valve endComponent of voltage, and AC transformer produces the alternating current voltage component between test product valve end；
(4), it is necessary to when adjusting DC voltage component between the end of test product valve, slowly adjust test product valve in process of the testModulated signal, it is ensured that DC voltage component between its end is slowly varying, and the voltage on such series capacitance CL can follow examinationVoltage DC component between the end of product valve, it is to avoid shoved in Transformer Winding because voltage difference is produced, therefore in test product valve direct currentIn component of voltage change procedure, the voltage on electric capacity CL also changes simultaneously, keeps test product valve and the total voltage on electric capacity CL and electricityThe source balance of voltage, so as to also achieve complementary energy of the AC power to test product valve；
(5) in process of the test, the modulated signal of control test product valve 1 and test product valve 2 so that the electric current in test product valve is met willAsk；Control the modulated signal of complementary energy valve so that the capacitor voltage balance in complementary energy valve, test product valve 1, test product valve 2, and meet experimentIt is required that.
Described is using the pressure regulator T1 methods charged：
Step 1: when starting, pressure regulator T1 being transferred to and is output as no-voltage, K01 is closed；
Step 2: then slow rise pressure regulator T1 output voltages, due to test product valve, series capacitance CL, transformer secondaryWinding is to be connected in series, if test product valve is made up of half-bridge cells, and test product valve is charged in the positive half-wave of AC power, and is exchangedThe negative half-wave of power supply charges to series capacitance CL；If test product valve is made up of full bridge unit, the positive and negative half-wave of AC power, electric currentAll unit is charged；If test product valve is made up of half-bridge cells and full bridge unit mixing, in the positive half-wave of AC power, electricityStream charges to all units, and the negative half-wave of AC power, and electric current charges to full bridge unit therein and series capacitance；
Step 3: waiting pressure regulator to rise to assigned voltage, charging terminates, the bridge arm capacitance voltage on test product valve at this momentWith the crest voltage equal to AC power plus the voltage on series capacitance CL, experiment can be started.
Described is using charging resistor R and charging resistor by-pass switch the K02 method charged：
Step 1: closing K01 first, start to test product valve and series capacitance CL chargings；
Step 2: because test product valve, series capacitance CL, transformer secondary winding are to be connected in series, if test product valve is by halfBridge unit is constituted, and test product valve is charged in the positive half-wave of AC power, and the negative half-wave of AC power charges to series capacitance CL；If test product valve is made up of full bridge unit, the positive and negative half-wave of AC power, electric current all charges to unit；If test product valve byHalf-bridge cells and full bridge unit mixing composition, in the positive half-wave of AC power, electric current charges to all units, and AC powerNegative half-wave, electric current charges to full bridge unit therein and series capacitance；
Step 3: waiting after end unit voltage stabilization to be charged, closure charging resistor by-pass switch K01；At this moment test productBridge arm capacitance voltage on valve and equal to AC power crest voltage plus the voltage on series capacitance CL, examination can be startedTest.
Described test method also includes following methods：In process of the test, test product valve 1, test product valve 2 and loop current suppression electricityRequired test current has been flowed through in anti-L01；The generation of test current is different with the debugging signal of test product valve 2 by test product valve 1Produce；Under typical test situation, the modulating wave of test product valve 1 and test product valve 2 is all given as sinusoidal signal, both amplitudes, frequencyIt is equal, differ a small angle；Therefore, on test product valve 1 and the loop current suppression reactor of the centre of test product valve 2, both will be bornThe difference of voltage, thus produce the sinusoidal circulation of an identical frequency；And capacitance voltage difference small between two test product valves willCause the DC component on loop current suppression reactor；Sinusoidal circulation and DC component have synthesized required test current.
In the experimental rig, the operation electricity needed for experiment is flowed through in test product valve 1, test product valve 2, loop current suppression reactance L01Stream, including AC compounent and DC component.In process of the test, the modulated signal of control test product valve 1 and test product valve 2 so that test productElectric current in valve, which is met, to be required；Adjust the secondary voltage of transformer so that the internal dc voltage of test product valve meets test requirements document.
Above example is implemented lower premised on technical solution of the present invention, gives detailed embodiment and toolThe operating process of body, but protection scope of the present invention is not limited to the above embodiments.Method therefor is such as without spy in above-described embodimentIt is conventional method not mentionlet alone bright.