CN107221921A - Soft straight transmission overhead line prevents the main electrical scheme method of submodule excessively stream - Google Patents
Soft straight transmission overhead line prevents the main electrical scheme method of submodule excessively stream Download PDFInfo
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- CN107221921A CN107221921A CN201710620197.2A CN201710620197A CN107221921A CN 107221921 A CN107221921 A CN 107221921A CN 201710620197 A CN201710620197 A CN 201710620197A CN 107221921 A CN107221921 A CN 107221921A
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- Prior art keywords
- bypass
- bridge arm
- submodule
- resistance
- overhead line
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H9/00—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection
- H02H9/02—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection responsive to excess current
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Rectifiers (AREA)
Abstract
The main electrical scheme method of submodule excessively stream is prevented the present invention relates to a kind of soft straight transmission overhead line, belongs to technical field of electric power.One is set to be bypassed by bypass IGCT and bypass resistance bridge arm in series between the upper and lower bridge arm of each phase of MMC transverters, two bypass IGCTs in bridge arm bypass use the form of reverse parallel connection, to ensure that the electric current in bridge arm bypass can two-way circulate；The energy of each phase upper and lower bridge arm inductance storage is discharged by bridge arm bypass circuit, and fault current reduces the electric current for flowing into submodule by resistance decrement.Due to the presence of bypass resistance, DC side current attenuation is accelerated, system is returned to normal operating condition as early as possible.And the obtaining value method of bypass resistance resistance is given, prevent bypass resistance excessive too small.
Description
Technical field
The present invention relates to technical field of electric power, more particularly to a kind of soft straight transmission overhead line prevents the master of submodule excessively stream
Mode of connection, avoids bridge arm inductive discharge from causing to damage to device in DC side failure.
Background technology
2001, modularization multi-level converter was proposed by German scholar R. Marquardt and A. Lesnicar, was promoted
The development of high voltage dc transmission technology.So far, China's Technology of HVDC based Voltage Source Converter is quickly grown, and that has put into operation is exemplary
Engineering includes：Shanghai Nanhui demonstration project, Nan'ao engineering, Zhoushan engineering and Xiamen engineering etc..Above-mentioned engineering uses direct current
Cable is transmitted electricity, but compared with overhead line, cable cost is high, and failure is generally permanent, is not easy to overhaul and safeguards.So, will
Technology of HVDC based Voltage Source Converter to overhead line field of power transmission extend be power network future development a trend.In addition, with new energy
Electricity needs constantly increases, and the MMC-HVDC systems of true dipolar configuration have played larger in the transmission of electricity occasion of high voltage, Large Copacity
Advantage.At present, the soft straight engineerings of Zhangbei County 500kV that will be built just are transmitted electricity using overhead line, and its current conversion station topology is very bipolar
Structure.
When a failure occurs it, after converter blocking AC inject fault current and bridge arm inductance freewheel current according to
So exist, this has very detrimental effect to switching device, especially when grounding resistance is smaller, inductive current decay is slower,
Device can be caused to bear prolonged overcurrent, and extend the fault clearance time.How fault current limiting, it is to avoid overcurrent
Device is caused to damage and how to accelerate DC side current attenuation, system is recovered normal operation as early as possible, is urgently to solve at present
Certainly the problem of.
The content of the invention
The main electrical scheme method of submodule excessively stream is prevented it is an object of the invention to provide a kind of soft straight transmission overhead line, is solved
The above mentioned problem that prior art of having determined is present.Fault current limiting of the present invention, it is to avoid overcurrent to change of current device cause damage with
And accelerate DC side current attenuation, system is recovered normal operation as early as possible.On the basis of the fault protecting method of Traditional DC side
Bridge arm bypass is with the addition of, the adverse effect that each bridge arm inductive discharge is caused to submodule is reduced.Bypassed by adding bridge arm, it is to avoid
Bridge arm inductive discharge causes to damage to device, and accelerates DC current to decay, and system is recovered normal operation as early as possible.
The above-mentioned purpose of the present invention is achieved through the following technical solutions：
Soft straight transmission overhead line prevents the main electrical scheme method of submodule excessively stream, between the upper and lower bridge arm of each phase of MMC transverters
One is set to be bypassed by bypass IGCT and bypass resistance bridge arm in series, two bypass IGCTs in bridge arm bypass are adopted
With the form of reverse parallel connection, to ensure that the electric current in bridge arm bypass can two-way circulate；The energy of each phase upper and lower bridge arm inductance storage
Amount is discharged by bridge arm bypass circuit, and fault current reduces the electric current for flowing into submodule, it is to avoid mistake by resistance decrement
Electric current causes to damage to change of current device, accelerates DC side current attenuation.
When current conversion station is normally run, bypass IGCT is off state, and bridge arm bypass does not work；Detect direct current double
After the short trouble of pole, locking IGBT immediately；If current conversion station is operated in rectification mode, triggering IGCT Tp1If current conversion station is operated in
Inverter mode, triggering IGCT Tp2；Only one of which is in the conduction state in two bypass IGCTs, and another is still in shut-off shape
State.
The discharge path of bridge arm inductance has two：One is discharged by submodule diode and dc-side short-circuit point, separately
One is discharged by bypassing IGCT and bypass resistance.
The higher limit of described bypass resistance determines that lower limit coordinates the value of bridge arm inductance according to minimum grounding resistance
To determine.
The beneficial effects of the present invention are：Increase bypass between each phase upper and lower bridge arm of transverter, reduce each bridge arm inductance and put
The adverse effect that electricity is caused to submodule.When a failure occurs it, by the shunting action of bypass, limitation flows into the failure of submodule
Electric current, it is to avoid overcurrent causes to damage to change of current device；Due to the presence of bypass resistance, DC side current attenuation is accelerated, is made
System returns to normal operating condition as early as possible.And the obtaining value method of bypass resistance resistance is given, prevent bypass resistance from crossing serious offense
It is small.
Brief description of the drawings
Accompanying drawing described herein is used for providing a further understanding of the present invention, constitutes the part of the application, this hair
Bright illustrative example and its illustrate to be used to explain the present invention, do not constitute inappropriate limitation of the present invention.
Fig. 1 is the MMC structural representations bypassed with bridge arm of the invention；
Fig. 2 is single-phase bridge arm inductive discharge path of the invention；
Fig. 3 is the flow chart of the fault clearance of the present invention.
Embodiment
The detailed content and its embodiment of the present invention is further illustrated below in conjunction with the accompanying drawings.
Referring to shown in Fig. 1 to Fig. 3, soft straight transmission overhead line of the invention prevents the main electrical scheme method of submodule excessively stream,
One is set between the upper and lower bridge arm of each phase of MMC transverters by bypass IGCT and bypass resistance bridge arm in series
Road, two bypass IGCTs in bridge arm bypass use the form of reverse parallel connection, can be double with the electric current ensured in bridge arm bypass
To circulation；The energy of each phase upper and lower bridge arm inductance storage is discharged by bridge arm bypass circuit, and fault current is declined by resistance
Subtract, reduce the electric current for flowing into submodule, it is to avoid overcurrent causes to damage to change of current device, accelerates DC side current attenuation.
Shown in Figure 1, when current conversion station is normally run, bypass IGCT is off state, and bridge arm bypass does not work.
Detect after DC bipolar short trouble, immediately locking IGBT.If current conversion station is operated in rectification mode, triggering IGCT Tp1If,
Current conversion station is operated in inverter mode, triggering IGCT Tp2.Only one of which is in the conduction state in two bypass IGCTs, another
Still in off state.
Shown in Figure 2, the discharge path of bridge arm inductance has two：One is short by submodule diode and DC side
Waypoint is discharged, and another is discharged by bypassing IGCT and bypass resistance.Select less bypass resistanceR p, inductance can be made
Electric current is most of to be flowed through from bridge arm bypass, so as to reduce the fault current for flowing through submodule, error protection effect is played to device.
After AC circuit breaker tripping operation, each bridge arm inductance continues through above-mentioned two paths and discharged, due to bridge arm bypass
Shunting action, the time that direct fault current decays to zero is greatly reduced, and then shortens failure recovery time.In trouble point
Arc extinction and surrounding medium recovers after insulation again, AC circuit breaker can carry out reclosing.Due to the presence of bypass resistance,
Bridge arm by-pass current is also constantly decayed, and when it is decayed to below the maintenance electric current of bypass IGCT, bypass IGCT is voluntarily closed
It is disconnected.The flow of whole fault clearance is as shown in Figure 3.
In the selection of bypass resistance, if from the perspective of protection submodule, bypass resistance is smaller, bridge arm by-pass current
Bigger, the fault current of submodule is smaller, is more conducive to protecting submodule.But if the value of bypass resistance is too small, bridge arm bypass
Current attenuation is slow, and bypass IGCT bears long-time overcurrent, may be burnt out because of overheat.So, should in Practical Project
Consider above-mentioned two aspects factor to choose bypass resistance, the higher limit of bypass resistance can be according to minimum grounding resistance come really
Fixed, lower limit needs to coordinate the value of bridge arm inductance to determine.
The preferred embodiment of the present invention is the foregoing is only, is not intended to limit the invention, for the technology of this area
For personnel, the present invention can have various modifications and variations.All any modification, equivalent substitution and improvements made for the present invention etc.,
It should be included in the scope of the protection.
Claims (4)
1. a kind of soft straight transmission overhead line prevents the main electrical scheme method of submodule excessively stream, it is characterised in that：It is each in MMC transverters
One is set to be bypassed by bypass IGCT and bypass resistance bridge arm in series between the upper and lower bridge arm of phase, in bridge arm bypass
Two bypass IGCTs use the form of reverse parallel connection, to ensure that the electric current in bridge arm bypass can two-way circulate；Above and below each phase
The energy of bridge arm inductance storage is discharged by bridge arm bypass circuit, and fault current reduces by resistance decrement and flows into submodule
The electric current of block.
2. soft straight transmission overhead line according to claim 1 prevents the main electrical scheme method of submodule excessively stream, its feature exists
In：When current conversion station is normally run, bypass IGCT is off state, and bridge arm bypass does not work；Detect DC bipolar short
After the failure of road, locking IGBT immediately；If current conversion station is operated in rectification mode, triggering IGCT Tp1If current conversion station is operated in inversion
Pattern, triggering IGCT Tp2；Only one of which is in the conduction state in two bypass IGCTs, and another is still in off state.
3. soft straight transmission overhead line according to claim 1 prevents the main electrical scheme method of submodule excessively stream, its feature exists
In：The discharge path of bridge arm inductance has two：One is discharged by submodule diode and dc-side short-circuit point, and another is
Discharged by bypassing IGCT and bypass resistance.
4. soft straight transmission overhead line according to claim 1 prevents the main electrical scheme method of submodule excessively stream, its feature exists
In：The higher limit of described bypass resistance determines that lower limit coordinates the value of bridge arm inductance to come true according to minimum grounding resistance
It is fixed.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710620197.2A CN107221921A (en) | 2017-07-26 | 2017-07-26 | Soft straight transmission overhead line prevents the main electrical scheme method of submodule excessively stream |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710620197.2A CN107221921A (en) | 2017-07-26 | 2017-07-26 | Soft straight transmission overhead line prevents the main electrical scheme method of submodule excessively stream |
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|---|---|
| CN107221921A true CN107221921A (en) | 2017-09-29 |
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|---|---|---|---|
| CN201710620197.2A Pending CN107221921A (en) | 2017-07-26 | 2017-07-26 | Soft straight transmission overhead line prevents the main electrical scheme method of submodule excessively stream |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109217265A (en) * | 2018-08-24 | 2019-01-15 | 东北电力大学 | A kind of removing DC Line Fault method of electric current transfevent multilevel converter topology |
| CN109617439A (en) * | 2018-12-28 | 2019-04-12 | 东南大学 | A kind of MMC topology with direct-current short circuit fault current blocking ability |
| CN110161369A (en) * | 2019-04-11 | 2019-08-23 | 华北电力大学 | A kind of bipolar short trouble localization method of DC grid based on overhead transmission line RL model |
-
2017
- 2017-07-26 CN CN201710620197.2A patent/CN107221921A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109217265A (en) * | 2018-08-24 | 2019-01-15 | 东北电力大学 | A kind of removing DC Line Fault method of electric current transfevent multilevel converter topology |
| CN109617439A (en) * | 2018-12-28 | 2019-04-12 | 东南大学 | A kind of MMC topology with direct-current short circuit fault current blocking ability |
| CN109617439B (en) * | 2018-12-28 | 2020-01-03 | 东南大学 | MMC topology with direct current short-circuit fault current blocking capability |
| CN110161369A (en) * | 2019-04-11 | 2019-08-23 | 华北电力大学 | A kind of bipolar short trouble localization method of DC grid based on overhead transmission line RL model |
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| PB01 | Publication | ||
| PB01 | Publication | ||
| WD01 | Invention patent application deemed withdrawn after publication |
Application publication date: 20170929 |
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| WD01 | Invention patent application deemed withdrawn after publication |