CN203166505U - AC side overvoltage protection device used for flexible DC transmission system - Google Patents
AC side overvoltage protection device used for flexible DC transmission system Download PDFInfo
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- CN203166505U CN203166505U CN 201320173885 CN201320173885U CN203166505U CN 203166505 U CN203166505 U CN 203166505U CN 201320173885 CN201320173885 CN 201320173885 CN 201320173885 U CN201320173885 U CN 201320173885U CN 203166505 U CN203166505 U CN 203166505U
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Abstract
The utility model relates to an AC side overvoltage protection device used for a flexible DC transmission system. The protection device is in parallel connection with two ends of a converter transformer valve side grounding resistor and is used for carrying out an action to guide fault current, inhibiting an overvoltage level of an AC line I (4) and protecting an AC valve body (9) when the AC line I (4) or a DC line (8) is failed to cause the overvoltage of the DC line (8) or when a valve base controller detects that the AC line I (4) has a short circuit fault. The protection device provided by the utility model has the advantages of rapid action, strong flow energy, large energy absorption, capability of protecting the valve body rapidly, no need of a control protection device with complex structure and function, simple structure, low cost, easy realization, the reduction of AC line and converter valve insulation costs, the guarantee of the safety of the AC line and converter valve equipment, the improvement of the fault resistance ability of a converter station, and the guarantee of the safe and stable operation of a DC power transmission system.
Description
Technical field
The utility model relates to flexible DC power transmission system field, is specifically related to a kind of for flexible DC power transmission system interchange side overvoltage protection.
Background technology
Flexible DC power transmission is a kind of novel high voltage dc transmission technology, and it at power supply places such as hydroelectric plant or thermal power plants, becomes direct current with the conventional AC electricity by the voltage-source type current transformer, by transmission lines such as overhead wire or cables, electric power is delivered to load place, a distant place.Compare with the conventional high-tension direct current transportation, it is strong to have controllability, and the trend counter-rotating need not advantages such as reactive power compensation easily.
The flexible DC power transmission system is made up of three parts; comprise two current conversion stations that are positioned at power supply and load place; and direct current cables or the overhead wire at connection two stations, wherein nucleus equipment is flexible DC converter valve, its fail safe need obtain to guarantee reliably by protection system.
Have in the current conversion station one can be in the converter valve 5 of alternating current circuit I and 8 switchings of DC line, comprise through the power semiconductor valve 9 of 8 of alternating current circuit I and DC line, by such power semiconductor valve parameters of electric power is changed between AC and DC.In addition, a converter transformer 3 is arranged between alternating current circuit I and the alternating current circuit II, it is wye connection in alternating current circuit I valve side, and its neutral point is by resistance 6 ground connection.
Flexible DC converter station failure generally is divided into and exchanges three kinds of side fault, DC side fault and converter valve faults, and AC and DC side error protection is by station control system (being made up of assemblies such as voltage transformer, current transformer, the protection of alternating current-direct current side filter, tranformer protections) realization.
The dc system fault situation is judged by the interior direct current protecting system of present flexible DC converter station mainly, overvoltage protection under-voltage by direct current; when one pole ground short circuit faults take place in single-phase or DC line 8 at current conversion station internal communication circuit I; the non-fault phase voltage of alternating current circuit I may be brought up to 1.5～2 times of normal working voltage, and power semiconductor valve 9 may bear too high false voltage and damage.
The main no gap MOV in parallel of conventional power semiconductors valve 9 safeguard measures.This guard method will not have the two ends that gap MOV is connected in parallel on power semiconductor valve 9 usually; utilize the electric current and voltage nonlinear characteristic of MOV; may produce superpotential energy consumes by MOV; thereby make protected equipment avoid the impact of overvoltage, but defective such as this method exists action parameter to be difficult to adjust, energy stress is excessive, conducting is uncontrollable.And there are complex structure in other traditional circuit protective device such as bypass thyristor switch, and operate time is slow, bear shortcomings such as overcurrent capability is low.At the problems referred to above, increase in parallel protective device of the present utility model can effectively reduce the alternating current circuit overvoltage on the converter transformer earth resistance, avoids change of current valve body inside is caused damage.
The utility model content
At the deficiencies in the prior art; the purpose of this utility model provides a kind of interchange side overvoltage protection that is applicable to the flexible DC power transmission system; protective device adopts overvoltage or forces to puncture element and improve the overvoltage protection performance, solved alternating current circuit overvoltage problem in the station that the flexible DC power transmission system failure causes well.
When single phase ground fault or DC line generation one pole ground short circuit fault took place alternating current circuit I usually, alternating current circuit I is non-, and the fault phase voltage can raise.According to predefined voltage; adjust ground connection and puncture the gap; when voltage when setting puncture voltage, not conducting of protective device, transmission system is delivering power normally; in case and overvoltage reaches set point; protective device is breakdown, produces electric spark, and short circuit current is imported into the earth by this gap; suppress alternating current circuit I overvoltage, avoid converter valve valve body 9 and alternating current circuit I to damage because of overvoltage.
The purpose of this utility model is to adopt following technical proposals to realize:
A kind of described protective device is included in flexible DC converter station 1 for flexible DC power transmission system interchange side overvoltage protection, and its improvements are, described protective device 7 is connected in parallel on earth resistance 6 two ends that are parallel to converter transformer 3.
Preferably, described protective device 7 adopts the breakover element of spark gap; Described spark gap ground connection.
Compared with the prior art, the beneficial effect that reaches of the utility model is:
1, the protective device that the utility model proposes is swift in motion, and through-flow energy is strong, and it is big to absorb energy, can protect valve body fast.
2, the control protective device that need not the 26S Proteasome Structure and Function complexity that the utility model proposes.
3, the protective device that the utility model proposes is simple in structure, and cost is low, is easy to realize.
4, reduce alternating current circuit and converter valve insulation costs;
5, ensure alternating current circuit and converter valve equipment safety;
6, improve current conversion station fault-resistant ability;
7, ensure the stable operation of flexible DC power transmission system safety.
Description of drawings
Fig. 1 exchanges side overvoltage protection schematic diagram for the flexible DC power transmission system;
Wherein: the flexible DC converter station of 1-; 2-alternating current circuit II; The 3-converter transformer; 4-alternating current circuit I; The 5-converter valve; 6-resistance; The 7-protective device; The 8-DC line; 9-converter valve valve body.
Embodiment
Below in conjunction with accompanying drawing embodiment of the present utility model is made further illustrated in greater detail.
The utility model provides is used for the alternating current circuit I of flexible DC power transmission system and converter valve overvoltage protection as shown in Figure 1, protective device is included in the converter valve 5 of alternating current circuit I and 8 switchings of DC line, be provided with converter transformer 3 between described alternating current circuit I and the alternating current circuit II, described converter transformer 3 is star-like connection in alternating current circuit I valve side, and its neutral point is by earth resistance 6 ground connection; Described converter transformer 3 is triangular form or star-like connection in alternating current circuit II net side.
Converter valve 5 is three-phase six brachium pontis structures; Each brachium pontis is formed by converter valve valve body 9; Described converter valve valve body 9 adopts thyristor to realize, comprises IGBT and diode antiparallel with it.Its version includes but not limited to modular multilevel, H bridge chain type, IGBT series connection.
On neutral resistance 6 two ends of described protective device 7 converter transformers in parallel; be used for causing overvoltage or when the valve base controller detects alternating current circuit I failed shorted at alternating current circuit I, DC line fault; move and draw away fault current; suppress alternating current circuit I overvoltage level, protection converter valve valve body 9.
Protective device 7 adopts the spark gap breakover element; Spark gap ground connection.
The operation principle of the spark gap of the employing that the utility model provides is as follows:
When spark gap made its voltage surpass from trigger voltage because of alternating current circuit I single-phase earthing or DC line one pole earth fault, seal clearance triggered automatically.
Or when converter valve control protective device detects change of current alternating current circuit I short trouble, send the forced-triggered order by optical fiber or cable and make its gap force conducting, make short circuit current flow through seal clearance fast.
Default puncture voltage size needs the assurance device can be not breakdown during overvoltage at alternating current circuit voltage, and can be breakdown when the electric voltage over press of alternating current circuit, and its big or small collocation method is for definite by theoretical calculating, Computer Simulation or test.The collocation method of discharging current size is for determining by theoretical calculating, Computer Simulation or test during puncture.Absorb the collocation method of energy size during puncture for determining by theoretical calculating, Computer Simulation or test.The self-breakdown voltage size is 1.3-1.8 times of circuit rated voltage, and the discharging current size is 1.5-20 circuit rated current during puncture, and absorbing the energy size during puncture is the product integration in time of above-mentioned voltage and electric current.
(1) determine that according to the calculating of flexible direct-current short circuit failure theory, Computer Simulation, test puncture voltage, short circuit current, the absorption energy particular content of spark gap are as follows:
Theoretical calculation process is: it is a voltage source U that converter transformer net top-cross is flowed bus 2 equivalences
sWith internal impedance Z
sSeries connection, according to converter transformer 3 no-load voltage ratio k and consider the anti-X of transformer valve side leakage
L, with voltage source U
sWith internal impedance Z
sConvert to transformer valve side.
Equivalence to the electromotive force of source of transformer valve side is: U
S2=kU
s
Internal resistance is: Z
S2=k
2Z
s+ X
L
Transformer voltage on valve side U during with normal operation
S20As initial condition, be 0 characteristics according to fault earthing place DC line (or alternating current circuit II is single-phase) voltage, set up the voltage of the non-fault phase of reflection ac bus at the mathematic(al) representation of earth fault process, calculate the false voltage expression formula of ac bus in the station according to initial condition and expression formula;
The non-fault phase voltage of ac bus u after the fault
Acn(t) be converter transformer valve side initial voltage U
S20, line impedance Z
S2With impedance ground Z
nFunction: u
Acn(t)=F (U
S20, Z
S2, Z
n, t); T represents the time.
Determine the puncture voltage of spark gap according to each phase voltage, alternating current circuit voltage peak (preferably 1.2 times) in the station when guaranteeing that this puncture voltage is higher than normal operation, the maximum of ac bus voltage when being lower than fault.In conjunction with the Mathematical Modeling of spark gap, can calculate discharging current, the absorption energy of spark gap under the false voltage effect.
The process of Computer Simulation is: in Computer Simulation software, set up valve system, transformer such as comprise, stand in the simulation model of DC line, converter valve and earth fault, by difference single-phase, two-phase earth fault emulation constantly, the amplitude of the non-fault phase voltage of ac bus in the station when obtaining fault.Determine the puncture voltage of spark gap according to this voltage, ac bus voltage (preferably 1.2 times) in the station when guaranteeing that this puncture voltage is higher than normal operation, the maximum of alternating voltage when being lower than fault.Set up the model of spark gap in simulation software, the maximum current that spark gap flows through during according to fault is determined the maximum current that spark gap allows.According to high-breakdown-voltage with allow maximum current to determine the energy that the spark gap needs absorb.
(2) determine the spacing distance of spark gap according to puncture voltage; Puncture voltage U is the function of gas pressure P and two interelectrode distance d and absolute temperature T: U=f(pd/T).
(3) a spark gap end in parallel is installed on the converter transformer valve side neutral resistance 6 other end ground connection;
(4) as accompanying drawing 1 when alternating current circuit I single-phase, two-phase ground connection or DC line one pole earth fault take place when, the spark gap both end voltage is increased to puncture voltage, thereby spark gap is punctured; Or when the alternating current circuit is short-circuited fault, voltage measuring apparatus or protective device monitoring spark gap both end voltage, the pilot spark gap by triggering forced-triggered afterflow gap, gap, punctures spark gap.
(5) short-circuit current flows through from spark gap, has suppressed alternating current circuit overvoltage level in the station, has avoided the overvoltage of converter valve valve body;
(6) after spark gap punctures, to control protective device return state information, when the control protective device detects the spark gap puncture, issue block signal to converter valve.
The utility model also relates to a kind of converter valve guard method for the alternating current circuit fault, and the protective device 7 that described method is used is parallel to converter transformer valve side neutral resistance 6 two ends; Described method comprises the steps:
Whether A, detection protective device break down, and described fault comprises alternating current circuit I single-phase earthing 10, DC line one pole earth fault 10 and bipolar short trouble;
B, when alternating current circuit I single-phase earthing or DC line one pole earth fault take place when, the spark gap both end voltage is increased to puncture voltage, the disruptive spark gap;
Among the described step B, when alternating current circuit one pole earth fault took place, namely the voltage of spark gap surpassed it from trigger voltage, and spark gap triggers automatically.
Maybe when the AC line short circuit fault took place, described protective device sent trigger command to spark gap, and forced-triggered afterflow gap punctures spark gap;
After C, spark gap puncture, send return state information to control device, and issue block signal to converter valve 5, realize protection converter valve valve body 9.
Should be noted that at last: above embodiment is only in order to illustrate that the technical solution of the utility model is not intended to limit, although with reference to above-described embodiment the utility model is had been described in detail, those of ordinary skill in the field are to be understood that: still can make amendment or be equal to replacement embodiment of the present utility model, and do not break away from any modification of the utility model spirit and scope or be equal to replacement, it all should be encompassed in the middle of the claim scope of the present utility model.
Claims (2)
1. one kind is used for flexible DC power transmission system interchange side overvoltage protection; described protective device is included in flexible DC converter station (1); it is characterized in that described protective device (7) is connected in parallel on earth resistance (6) two ends that are parallel to converter transformer (3).
2. interchange side overvoltage protection as claimed in claim 1 is characterized in that described protective device (7) adopts the breakover element of spark gap; Described spark gap ground connection.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201320173885 CN203166505U (en) | 2013-04-09 | 2013-04-09 | AC side overvoltage protection device used for flexible DC transmission system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201320173885 CN203166505U (en) | 2013-04-09 | 2013-04-09 | AC side overvoltage protection device used for flexible DC transmission system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN203166505U true CN203166505U (en) | 2013-08-28 |
Family
ID=49027665
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 201320173885 Expired - Lifetime CN203166505U (en) | 2013-04-09 | 2013-04-09 | AC side overvoltage protection device used for flexible DC transmission system |
Country Status (1)
| Country | Link |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105449704A (en) * | 2015-12-10 | 2016-03-30 | 特变电工新疆新能源股份有限公司 | Flexible direct-current power transmission system and direct-current fault processing method thereof |
| CN106410774A (en) * | 2016-09-26 | 2017-02-15 | 成都交大光芒科技股份有限公司 | Train on-board industrial camera protection device |
| CN107957536A (en) * | 2017-10-16 | 2018-04-24 | 许继电气股份有限公司 | Sychronisation and pilot system are tested in a kind of aperiodic triggering of direct-current transmission converter valve |
| CN112968462A (en) * | 2021-02-20 | 2021-06-15 | 国网冀北电力有限公司检修分公司 | Converter station overvoltage control method, pole control system and overvoltage control system |
-
2013
- 2013-04-09 CN CN 201320173885 patent/CN203166505U/en not_active Expired - Lifetime
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105449704A (en) * | 2015-12-10 | 2016-03-30 | 特变电工新疆新能源股份有限公司 | Flexible direct-current power transmission system and direct-current fault processing method thereof |
| CN105449704B (en) * | 2015-12-10 | 2018-11-02 | 特变电工新疆新能源股份有限公司 | Flexible direct-current power transmission system and direct-current fault processing method thereof |
| CN106410774A (en) * | 2016-09-26 | 2017-02-15 | 成都交大光芒科技股份有限公司 | Train on-board industrial camera protection device |
| CN107957536A (en) * | 2017-10-16 | 2018-04-24 | 许继电气股份有限公司 | Sychronisation and pilot system are tested in a kind of aperiodic triggering of direct-current transmission converter valve |
| CN107957536B (en) * | 2017-10-16 | 2019-12-10 | 许继电气股份有限公司 | Non-periodic trigger test synchronization device and non-periodic trigger test system for direct-current transmission converter valve |
| CN112968462A (en) * | 2021-02-20 | 2021-06-15 | 国网冀北电力有限公司检修分公司 | Converter station overvoltage control method, pole control system and overvoltage control system |
| CN112968462B (en) * | 2021-02-20 | 2022-11-22 | 国网冀北电力有限公司检修分公司 | Converter station overvoltage control method, pole control system and overvoltage control system |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CX01 | Expiry of patent term |
Granted publication date: 20130828 |
|
| CX01 | Expiry of patent term |