CN105811744A - Auxiliary valve segment parallel capacitor type converter improving LCC-HVDC commutation characteristic and method thereof - Google Patents
Auxiliary valve segment parallel capacitor type converter improving LCC-HVDC commutation characteristic and method thereof Download PDFInfo
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- CN105811744A CN105811744A CN201410855784.6A CN201410855784A CN105811744A CN 105811744 A CN105811744 A CN 105811744A CN 201410855784 A CN201410855784 A CN 201410855784A CN 105811744 A CN105811744 A CN 105811744A
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- auxiliary valve
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- inverter
- condenser type
- brachium pontis
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Abstract
The invention relates to an auxiliary valve segment parallel capacitor type converter improving an LCC-HVDC commutation characteristic and a method thereof. The converter is composed of three phases. Each phase is composed of upper and lower bridge arms which are connected in series and are of the same structure. Upper and lower bridge arms are composed of auxiliary valve sections which are connected in parallel. Each auxiliary valve section is composed of auxiliary valves which are connected in series. A capacitor is connected in parallel between two adjacent auxiliary valves in an auxiliary valve section. According to the converter provided by the invention, the auxiliary valves and the parallel capacitors are used; only when the failure of failed commutation is monitored, the auxiliary valves and the parallel capacitor are used to apply reverse voltage on a corresponding thyristor in commutation; a turn-off angle is increased; a traditional LCC-HVDC commutation characteristic is improved; under normal circumstances, the auxiliary valves and the parallel capacitors are not used, so that a large number of harmonics are prevented; and engineering practicality is realized.
Description
Technical field
The present invention relates to a kind of inverter and method thereof, in particular to a kind of auxiliary valve sectional parallel condenser type inverter improving LCC-HVDC commutation characteristic and method thereof.
Background technology
When two valves of inverter carry out commutation, because commutation process fails to carry out complete, or after estimating the valve breakdown turned off, fail to recover blocking ability during backward voltage, when the voltage being added on this valve is timing, again turn on immediately, then there occurs and switch phase, making the valve that expectation is opened again turn off, this phenomenon is referred to as commutation failure.
When two valves of inverter carry out commutation, because commutation process fails to carry out complete, or after estimating the valve breakdown turned off, fail to recover blocking ability during backward voltage, when the voltage being added on this valve is timing, again turn on immediately, then there occurs and switch phase, making the valve that expectation is opened again turn off, this phenomenon is referred to as commutation failure.
Commutation failure is inverter in DC transmission system, especially one of more incident fault of inverter.Additional converter circuit is set, forces the commutation mode applying backward voltage or reverse current to be called forced commutation to the IGCT being intended to turn off.Forced commutation generally utilizes stored energy on additional capacitor to realize, and therefore also becomes the electric capacity change of current.Forced commutation includes: direct coupling type forced commutation and inductive coupling forced commutation.
Wherein direct coupling type forced commutation is directly provided the mode of change of current voltage to be called direct coupling type forced commutation by electric capacity in converter circuit.When IGCT VT is in on-state, press the charging of figure Semi-polarity in advance electric capacity C.If closing a switch S, so that it may so that IGCT is applied in direction voltage and turns off.
If provided change of current voltage or change of current electric current by the coupling of the electric capacity in converter circuit and inductance, then it is called inductive coupling forced commutation.IGCT turns off within first half period of LC, and IGCT turns off within second half period of LC.Because during turn on thyristors, in two figure, electric capacity both end voltage polarity is different.In these two kinds of situations, during brilliant electric current, brake tube is all turn off when forward current is down to zero and diode starts to flow.The tube voltage drop of diode is exactly the backward voltage being added on IGCT.
Current forces commutation inverter, in commutation process each time, all needs to utilize serial or parallel connection auxiliary charging and discharging circuit on inverter to carry out commutation, causes electric capacity discharge and recharge continually, and this process can produce substantial amounts of harmonic wave, causes new technical barrier.
Summary of the invention
For solving above-mentioned deficiency of the prior art, it is an object of the invention to provide a kind of auxiliary valve sectional parallel condenser type inverter improving LCC-HVDC commutation characteristic and method thereof, the inverter of the present invention utilizes auxiliary valve and shunt capacitance, only when monitoring commutation failure fault, utilize auxiliary valve and shunt capacitance, corresponding thyristor valve in commutation is applied backward voltage, increases and close the angle of rupture, improve traditional LC C-HVDC commutation characteristic.Under normal circumstances, auxiliary valve and shunt capacitance will not be put into, thus do not produce a large amount of harmonic wave, possess engineering practicability.
It is an object of the invention to adopt following technical proposals to realize:
The present invention provides a kind of auxiliary valve sectional parallel condenser type inverter improving LCC-HVDC commutation characteristic, and described auxiliary valve sectional parallel condenser type inverter is made up of three-phase, is often made up of upper and lower two brachium pontis that the structure connected is identical；It thes improvement is that, described upper and lower two brachium pontis are by auxiliary valve section composition in parallel, and each auxiliary valve section is composed in series by auxiliary valve；Auxiliary valve section is parallel with capacitor between adjacent two auxiliary valves.
Further, what one end of described upper and lower two brachium pontis passed sequentially through that inductance is connected to auxiliary valve sectional parallel condenser type inverter with transformator exchanges end；The other end of described upper and lower two brachium pontis is connected with the two other phase brachium pontis other end, forms the both positive and negative polarity bus of auxiliary valve sectional parallel condenser type inverter DC terminal；Described auxiliary valve is IGCT.
Further, described auxiliary valve sectional parallel condenser type inverter is connected with the control system in current conversion station；Brachium pontis IGCT is carried out segmentation by described auxiliary valve sectional parallel condenser type inverter, designs shunt capacitance.
The present invention provides the phase change method of a kind of auxiliary valve sectional parallel condenser type inverter improving LCC-HVDC commutation characteristic, its feature improvements A, the shnt capacitor in inverter is sequentially carried out precharge；
Control protection system in B, current conversion station has monitored whether commutation failure；
After C, commutation complete, in inverter, all of auxiliary valve is by natural disconnection, and polarity of capacitor change in parallel, during brachium pontis normal commutation next time, by triggering and conducting auxiliary valve.
Further, in described step A, auxiliary valve sectional parallel condenser type inverter sends precharge and triggers pulse, and the shnt capacitor in inverter is sequentially carried out precharge.
Further, shnt capacitor carries out precharge mode for the alternately corresponding even number auxiliary valve section of triggering and conducting upper and lower bridge arm and odd number auxiliary valve section.
Further; in described step B; when controlling protection system monitoring in current conversion station to during without commutation failure fault; then inverter works according to the mode of common inverter, when controlling protection system monitoring in current conversion station to commutation failure, when next brachium pontis starts commutation; the auxiliary valve of the positive polarity side of this brachium pontis shnt capacitor of triggering and conducting simultaneously; make capacitor discharge, carry out tapping and applying back-pressure, to reverse charging to reversal.
Compared with immediate prior art, the excellent effect that technical scheme provided by the invention has is:
1, adopt auxiliary valve sectional parallel condenser type inverter, commutation failure fault can be prevented effectively from, and a large amount of harmonic wave will not be produced, possess engineering practicability.
2 and Control protection system with the use of; auxiliary valve and shunt capacitance do not come into operation when inverter is properly functioning; only when Control protection system monitors commutation failure fault; send and trigger pulse accordingly; the valve of conducting shunt capacitance positive polarity side; carry out tapping and applying back-pressure, resist commutation failure.Controlling flexibly, effect is notable, and straight-flow system will not cause long-term added influence.
3, converter bridge arm according to the actual demand of different engineerings, can be carried out equitable subsection, option and installment electric capacity quantity and parameter, has the feature of flexible design by inverter.
Accompanying drawing explanation
Fig. 1 is auxiliary valve sectional parallel condenser type inverter (inverter) topological diagram provided by the invention；
Fig. 2 is valve 4 provided by the invention and valve 5 shnt capacitor pre-charge process figure；
Fig. 3 is the polarity schematic diagram after all shunt capacitances provided by the invention precharge；
The discharge process of shunt capacitance when Fig. 4 is valve 3 provided by the invention and valve 5 commutation；
Fig. 5 is the normal commutation process of valve next time 3 provided by the invention and valve 5
Fig. 6 is that inverter provided by the invention triggers pulse schematic diagram.
Detailed description of the invention
Below in conjunction with accompanying drawing, the specific embodiment of the present invention is described in further detail.
When AC system breaks down, produce the problem such as disturbance and voltage-regulation difficulty, all easily cause the commutation failure of traditional LC C inverter.Therefore, to possess the inverter improving commutation characteristic effect significant in research.
The technology groups composition of the present invention is three parts: first, auxiliary valve sectional parallel condenser type inverter, utilizes auxiliary valve to carry out shunting and the mode of shunt capacitance applying backward voltage, can effectively resist commutation failure；Secondly, with Control protection system in station with the use of, do not come into operation time properly functioning, triggering work the same as common inverter；When Control protection system monitors commutation failure fault, control to send commutation failure and trigger pulse, make the auxiliary valve section of corresponding capacitance positive polarity side turn on, carry out tapping and applying back-pressure, assist commutation；Finally, brachium pontis IGCT according to the requirement of the demand of concrete engineering and economy, can be carried out flexible segmentation, the shunt capacitance of design suitable quantity and parameter by auxiliary valve sectional parallel condenser type inverter.
Common inverter working method is: normal condition, does not put into auxiliary valve and electric capacity (one group of the left sides of two groups of auxiliary valve sections namely in parallel in accompanying drawing 1), the same with common inverter, according to V1 to V6 successively triggering and conducting.
The present invention provides a kind of auxiliary valve sectional parallel condenser type inverter improving LCC-HVDC commutation characteristic, this converter circuit topology is as shown in Figure 1: described auxiliary valve sectional parallel condenser type inverter is made up of three-phase, is often made up of upper and lower two brachium pontis that the structure connected is identical；Described upper and lower two brachium pontis are by auxiliary valve section composition in parallel, and each auxiliary valve section is composed in series by auxiliary valve；Auxiliary valve section is parallel with capacitor between adjacent two auxiliary valves.What one end of described upper and lower two brachium pontis passed sequentially through that inductance is connected to auxiliary valve sectional parallel condenser type inverter with transformator exchanges end；The other end of described upper and lower two brachium pontis is connected with the two other phase brachium pontis other end, forms the both positive and negative polarity bus of auxiliary valve sectional parallel condenser type inverter DC terminal；Described auxiliary valve is IGCT.Described auxiliary valve sectional parallel condenser type inverter is connected with the control system in current conversion station.
The present invention also provides for the phase change method of a kind of auxiliary valve sectional parallel condenser type inverter improving LCC-HVDC commutation characteristic, comprises the steps:
A, first, sends corresponding precharge and triggers pulse, the shunt capacitance in inverter is sequentially carried out precharge.For auxiliary valve 4 and auxiliary valve 5, trigger auxiliary valve V42、V44、V46……V4n, V52、V54、V56……V5n, auxiliary valve V41’、V43’、V45’……V4n-1', V51’、V53’、V55’……V5n-1', so as to turn on, to electric capacity C41、C42……C4m, C51、C52……C5mCharging, so as to polarity as shown in Figure 2 on band.Electric capacity C can be made in the same manner11、C12……C1m, C21、C22……C2m..., C61、C62……C6mPolarity as shown in Figure 3 on band.
Control protection system in B, current conversion station has monitored whether commutation failure；During fault without commutation failure, inverter works according to the mode of common inverter, when controlling protection system monitoring in station to commutation failure; when next brachium pontis starts commutation; simultaneously the auxiliary valve of this brachium pontis shunt capacitance positive polarity side of triggering and conducting, makes electric capacity discharge, to reverse charging to reversal.For the valve 3 commutation process to valve 5, send and trigger pulse accordingly, trigger auxiliary valve V52’、V54’、V56’……V5n', so as to turn on, electric capacity C51、C52……C5mStarting electric discharge, electric discharge will continue reverse charging after terminating, and make electric capacity change polarity, as shown in Figure 4.In this process, auxiliary valve and shunt capacitance play shunting DC current and the valve needing to turn off apply the effect of backward voltage, thus the turn off process of acceleration valve, improve commutation characteristic, it is to avoid commutation failure.
After C, commutation complete, all of auxiliary valve is by natural disconnection, and electric capacity change in polarity, during the normal commutation next time of this brachium pontis, by triggering and conducting auxiliary valve, as shown in Figure 5.The triggering pulse schematic diagram of this inverter as shown in Figure 6, wherein, PiRefer to the triggering pulse to all IGCTs of valve i, Pi1Refer to the triggering pulse to valve i odd number section IGCT, Pi2Refer to the triggering pulse to valve i even number section IGCT, Pi' refer to the triggering pulse to all IGCTs of auxiliary valve i, Pi1' refer to the triggering pulse to auxiliary valve i odd number section IGCT, Pi2' refer to the triggering pulse to auxiliary valve i even number section IGCT.
Finally should be noted that: above example is only in order to illustrate that technical scheme is not intended to limit; although the present invention being described in detail with reference to above-described embodiment; the specific embodiment of the present invention still can be modified or equivalent replacement by those of ordinary skill in the field; these are without departing from any amendment of spirit and scope of the invention or equivalent replace, within the claims of the present invention all awaited the reply in application.
Claims (7)
1. improving an auxiliary valve sectional parallel condenser type inverter for LCC-HVDC commutation characteristic, described auxiliary valve sectional parallel condenser type inverter is made up of three-phase, is often made up of upper and lower two brachium pontis that the structure connected is identical；It is characterized in that, described upper and lower two brachium pontis are by auxiliary valve section composition in parallel, and each auxiliary valve section is composed in series by auxiliary valve；Auxiliary valve section is parallel with capacitor between adjacent two auxiliary valves.
2. auxiliary valve sectional parallel condenser type inverter as claimed in claim 1, it is characterised in that what one end of described upper and lower two brachium pontis passed sequentially through that inductance is connected to auxiliary valve sectional parallel condenser type inverter with transformator exchanges end；The other end of described upper and lower two brachium pontis is connected with the two other phase brachium pontis other end, forms the both positive and negative polarity bus of auxiliary valve sectional parallel condenser type inverter DC terminal；Described auxiliary valve is IGCT.
3. auxiliary valve sectional parallel condenser type inverter as claimed in claim 1, it is characterised in that described auxiliary valve sectional parallel condenser type inverter is connected with the control system in current conversion station；Brachium pontis IGCT is carried out segmentation by described auxiliary valve sectional parallel condenser type inverter, designs shunt capacitance.
4. the phase change method of the auxiliary valve sectional parallel condenser type inverter improving LCC-HVDC commutation characteristic as according to any one of claim 1-3, it is characterised in that described method comprises the steps:
A, the shnt capacitor in inverter is sequentially carried out precharge；
Control protection system in B, current conversion station has monitored whether commutation failure；
After C, commutation complete, in inverter, all of auxiliary valve is by natural disconnection, and polarity of capacitor change in parallel, during brachium pontis normal commutation next time, by triggering and conducting auxiliary valve.
5. phase change method as claimed in claim 4, it is characterised in that in described step A, auxiliary valve sectional parallel condenser type inverter sends precharge and triggers pulse, and the shnt capacitor in inverter is sequentially carried out precharge.
6. phase change method as claimed in claim 5, it is characterised in that shnt capacitor carries out precharge mode for the alternately corresponding even number auxiliary valve section of triggering and conducting upper and lower bridge arm and odd number auxiliary valve section.
7. phase change method as claimed in claim 4; it is characterized in that; in described step B, when controlling protection system monitoring in current conversion station to during without commutation failure fault, then inverter works according to the mode of common inverter; when controlling protection system monitoring in current conversion station to commutation failure; when next brachium pontis starts commutation, the auxiliary valve of the positive polarity side of this brachium pontis shnt capacitor of triggering and conducting, makes capacitor discharge simultaneously; carry out tapping and applying back-pressure, to reverse charging to reversal.
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| CN201410855784.6A CN105811744A (en) | 2014-12-31 | 2014-12-31 | Auxiliary valve segment parallel capacitor type converter improving LCC-HVDC commutation characteristic and method thereof |
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| CN201410855784.6A CN105811744A (en) | 2014-12-31 | 2014-12-31 | Auxiliary valve segment parallel capacitor type converter improving LCC-HVDC commutation characteristic and method thereof |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107026466A (en) * | 2017-06-02 | 2017-08-08 | 华中科技大学 | Symmetrical bipolar MMC HVDC devices, system and fault traversing control method |
| CN109510503A (en) * | 2018-12-21 | 2019-03-22 | 博众精工科技股份有限公司 | A kind of highly reliable, redundancy inverter circuit |
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| JP2000092879A (en) * | 1998-09-11 | 2000-03-31 | Toshiba Corp | Motor drive |
| CN2396568Y (en) * | 1999-11-09 | 2000-09-13 | 本溪高中频电源设备总厂 | Self-phase-change inverter |
| CN103323790A (en) * | 2013-06-07 | 2013-09-25 | 华北电力大学 | Phase commutation failure analytical method based on direct-current transmission inverting side two-phase short-circuit fault |
| CN103825484A (en) * | 2014-03-06 | 2014-05-28 | 华北电力大学 | Novel forced phase-changing bridge circuit |
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2014
- 2014-12-31 CN CN201410855784.6A patent/CN105811744A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2000092879A (en) * | 1998-09-11 | 2000-03-31 | Toshiba Corp | Motor drive |
| CN2396568Y (en) * | 1999-11-09 | 2000-09-13 | 本溪高中频电源设备总厂 | Self-phase-change inverter |
| CN103323790A (en) * | 2013-06-07 | 2013-09-25 | 华北电力大学 | Phase commutation failure analytical method based on direct-current transmission inverting side two-phase short-circuit fault |
| CN103825484A (en) * | 2014-03-06 | 2014-05-28 | 华北电力大学 | Novel forced phase-changing bridge circuit |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107026466A (en) * | 2017-06-02 | 2017-08-08 | 华中科技大学 | Symmetrical bipolar MMC HVDC devices, system and fault traversing control method |
| CN107026466B (en) * | 2017-06-02 | 2020-02-14 | 华中科技大学 | Symmetric bipolar MMC-HVDC device, system and fault ride-through control method |
| CN109510503A (en) * | 2018-12-21 | 2019-03-22 | 博众精工科技股份有限公司 | A kind of highly reliable, redundancy inverter circuit |
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Address after: 100031 Xicheng District West Chang'an Avenue, No. 86, Beijing Applicant after: State Grid Corporation of China Applicant after: GLOBAL ENERGY INTERCONNECTION Research Institute Applicant after: CHINA-EPRI ELECTRIC POWER ENGINEERING Co.,Ltd. Applicant after: ELECTRIC POWER RESEARCH INSTITUTE OF STATE GRID SHANDONG ELECTRIC POWER Co. Address before: 100031 Xicheng District West Chang'an Avenue, No. 86, Beijing Applicant before: State Grid Corporation of China Applicant before: STATE GRID SMART GRID Research Institute Applicant before: CHINA-EPRI ELECTRIC POWER ENGINEERING Co.,Ltd. Applicant before: ELECTRIC POWER RESEARCH INSTITUTE OF STATE GRID SHANDONG ELECTRIC POWER Co. |
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Effective date of registration: 20170605 Address after: 100031 Xicheng District West Chang'an Avenue, No. 86, Beijing Applicant after: State Grid Corporation of China Applicant after: GLOBAL ENERGY INTERCONNECTION Research Institute Applicant after: ELECTRIC POWER RESEARCH INSTITUTE OF STATE GRID SHANDONG ELECTRIC POWER Co. Address before: 100031 Xicheng District West Chang'an Avenue, No. 86, Beijing Applicant before: State Grid Corporation of China Applicant before: GLOBAL ENERGY INTERCONNECTION Research Institute Applicant before: CHINA-EPRI ELECTRIC POWER ENGINEERING Co.,Ltd. Applicant before: ELECTRIC POWER RESEARCH INSTITUTE OF STATE GRID SHANDONG ELECTRIC POWER Co. |
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Application publication date: 20160727 |