CN112865040A - Multi-port direct current circuit breaker and control method thereof - Google Patents
Multi-port direct current circuit breaker and control method thereof Download PDFInfo
- Publication number
- CN112865040A CN112865040A CN202110214718.0A CN202110214718A CN112865040A CN 112865040 A CN112865040 A CN 112865040A CN 202110214718 A CN202110214718 A CN 202110214718A CN 112865040 A CN112865040 A CN 112865040A
- Authority
- CN
- China
- Prior art keywords
- branch
- current
- unit
- switching
- auxiliary
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J1/00—Circuit arrangements for dc mains or dc distribution networks
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/26—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured
- H02H7/267—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured for parallel lines and wires
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/26—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured
- H02H7/268—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured for dc systems
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J1/00—Circuit arrangements for dc mains or dc distribution networks
- H02J1/08—Three-wire systems; Systems having more than three wires
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Driving Mechanisms And Operating Circuits Of Arc-Extinguishing High-Tension Switches (AREA)
Abstract
The invention relates to the technical field of power electronics, in particular to a multi-port direct current circuit breaker and a control method thereof, wherein the multi-port direct current circuit breaker comprises a switching-off unit, one end of the switching-off unit is connected with a direct current bus, and the switching-off unit at least comprises a first power electronic switch unit; one end of each through-current branch is connected with the direct-current bus, each through-current branch at least comprises a first mechanical switch, and each through-current branch is used for controlling the on-off of a corresponding line; the auxiliary branch units are provided with auxiliary branch units which correspond to the through-current branches one by one, and two ends of each auxiliary branch unit are respectively connected with the other end of the cut-off unit and the other end of the through-current branch and used for assisting in conducting current in the switching-off and switching-on processes and isolating each circuit after switching-off; the auxiliary branch unit is provided with a first auxiliary branch and a second auxiliary branch, and the conduction directions of the first auxiliary branch and the second auxiliary branch are opposite. The using quantity of the full-control devices is saved by more than 50% by sharing the breaking units.
Description
Technical Field
The invention relates to the technical field of power electronics, in particular to a multi-port direct current circuit breaker and a control method thereof.
Background
Nowadays, a direct current power transmission and distribution technology becomes an effective means for large-scale delivery and consumption of renewable energy sources such as wind, light and the like, and a high-voltage direct current breaker is a key device for developing the direct current power transmission and distribution to more economical and flexible networking.
With the development of high-voltage large-capacity direct-current power grids, the use number of the circuit breakers is increased, and the requirement for the breaking capacity of the circuit breakers is increased, so that the power grids have higher requirements for the technology and the economy of the high-voltage direct-current circuit breakers. The mechanical direct current circuit breaker is strong in breaking capacity and high in economical efficiency, but the small current breaking difficulty and the cost of the energy storage device caused by multiple reclosing requirements are greatly increased, and the improvement of the breaking capacity is restricted. The breaking capacity of the hybrid circuit breaker is limited by the inherent current-cutting capacity of the full-control device, and the adoption of a large number of full-control devices causes the circuit breaker to be high in cost.
Disclosure of Invention
In view of this, embodiments of the present invention provide a multi-port dc circuit breaker and a control method thereof, so as to solve the problem of balancing the breaking capacity and the manufacturing cost.
According to a first aspect, an embodiment of the present invention provides a multi-port dc circuit breaker, including:
the switching-off unit is connected with the direct current bus at one end and at least comprises a first power electronic switch unit;
one end of each through-current branch is connected with the direct-current bus, each through-current branch at least comprises a first mechanical switch, and each through-current branch is used for controlling the on-off of a corresponding line;
the auxiliary branch units are provided with one-to-one correspondence between the auxiliary branch units and the through-flow branches, two ends of each auxiliary branch unit are respectively connected with the other end of the cut-off unit and the other end of the through-flow branch, and the auxiliary branch units are used for isolating each circuit; the auxiliary branch unit is provided with a first auxiliary branch and a second auxiliary branch, and the conduction directions of the first auxiliary branch and the second auxiliary branch are opposite.
According to the multi-port direct current circuit breaker provided by the embodiment of the invention, the using quantity of full-control devices can be saved by more than 50% by sharing the switching-on/off unit, and the multi-port direct current circuit breaker is realized by combining the mechanical switch and the power electronic switch unit, so that the voltage isolation between lines under the stable state and the fault switching-on/off working condition can be realized, the isolation cost can be reduced, and the balance between the switching-on/off capacity and the manufacturing cost is ensured.
Optionally, the disconnection unit includes a disconnection branch and an energy consumption branch connected in parallel, where the disconnection branch has the first power electronic switch unit;
the through-current branch further comprises a second power electronic switching unit in series with the first mechanical switch.
Optionally, the disconnection unit includes a disconnection branch and an energy consumption branch connected in parallel, where the disconnection branch further includes a negative voltage coupling switch connected in series with the first power electronic switch unit;
the current branch has the first mechanical switch.
Optionally, the negative pressure coupling switch includes: the capacitor is connected with the third power electronic switch in series and then connected with the primary side of the coupling reactor in series, and the secondary side of the coupling reactor is connected with the first power electronic switch unit in series.
Optionally, the energy consuming branch comprises a non-linear resistance unit.
Optionally, the auxiliary branch unit includes: a third power electronic switching unit or diode unit.
According to the multi-port direct current circuit breaker provided by the embodiment of the invention, each auxiliary branch circuit unit can independently cut off each line short-circuit current, and meanwhile, the multi-outlet short-circuit fault simultaneous cutting-off and direct current bus fault clearing capabilities are achieved.
Optionally, the third power electronic switching unit comprises:
the first power electronic switch and the one-way choke switch are connected in series;
or the like, or, alternatively,
and the second power electronic switches are connected in series in sequence.
Optionally, the diode unit includes:
a first diode connected in series in sequence;
or the like, or, alternatively,
the diode unit includes:
at least two diode branches connected in parallel;
a fourth power electronic switch in series with the at least two diode branches after parallel connection.
According to a second aspect, an embodiment of the present invention further provides a control method for a multi-port dc circuit breaker, where the control method is used in the above-mentioned multi-port dc circuit breaker, and the control method includes:
acquiring the working state of the multi-port direct current circuit breaker;
and switching the conduction states of the cut-off unit, the corresponding current branch circuit and the corresponding auxiliary branch circuit unit based on the working state.
According to the control method of the multi-port direct current circuit breaker, provided by the embodiment of the invention, the working state of the multi-port direct current circuit breaker is monitored, and the conduction states of each cut-off unit, the through-current branch circuit and the auxiliary branch circuit unit are correspondingly controlled according to the monitoring result, so that the short-circuit current can be rapidly transferred, limited and cut-off, and the cut-off current can reach tens of kA.
Optionally, when the multi-port dc circuit breaker is put into operation, the switching the conduction states of the breaking unit, the corresponding current branch and the corresponding auxiliary branch unit based on the operating state includes:
switching on a switching-off branch in the switching-off unit so as to enable current to flow through the switching-off unit;
when a closing judgment condition is met, a first mechanical switch in the through-flow branch is closed, so that current flows from the through-flow branch.
Optionally, when at least one preset line short-circuit fault of the multi-port dc circuit breaker is disconnected, switching the conduction states of the disconnection unit, the corresponding through-current branch and the corresponding auxiliary branch unit based on the operating state includes:
switching on a switching unit in the switching-off branch and locking a first preset through-current branch corresponding to the at least one preset line so as to force current to be transferred to the switching-off branch and the first auxiliary branch;
when the current of the at least one first preset current branch passes through zero, a first mechanical switch in the at least one first preset current branch is switched off;
latching the open branch and charging a capacitor in the open branch to transfer the current to the energy consuming branch;
and when the voltage of the energy consumption branch circuit is higher than the voltage of the multi-port direct current circuit breaker, the current of the at least one first preset current branch circuit is switched on and off.
Optionally, when the dc bus short-circuit fault is disconnected, the switching the conduction states of the disconnection unit, the corresponding through-current branch circuit, and the corresponding auxiliary branch circuit unit based on the operating state includes:
switching on a switching unit in the switching-off branch and locking each through-current branch to force current to be transferred to the switching-off branch and the second auxiliary branch;
when the current of each current branch passes through zero, a first mechanical switch in each current branch is switched off;
latching the open branch and charging a capacitor in the open branch to transfer the current to the energy consuming branch;
and when the voltage of the energy consumption branch circuit is higher than that of the multi-port direct current circuit breaker, the current of each through-current branch circuit is switched on and off.
Optionally, when a line in which a second preset current branch is located is short-circuited and the first mechanical switch in the second preset current branch fails, switching the on-state of the switching unit, the corresponding current branch, and the corresponding auxiliary branch unit based on the operating state includes:
keeping the second preset current branch on, and conducting the second auxiliary branch;
latching the other current branches and the first auxiliary branch to force current to be transferred to the second preset current branch and the second auxiliary branch;
when the current of the rest of the through-current branches passes through zero, the first mechanical switches of the rest of the through-current branches are switched off and the cut-off branches are locked, so that the isolation of the rest of the through-current branches is completed.
According to the control method of the multi-port direct current circuit breaker, provided by the embodiment of the invention, after the first mechanical switch of the through-current branch fails, the auxiliary branch is used for providing a path for current to realize sound line isolation, so that the flexibility and reliability of the circuit breaker are greatly improved.
Optionally, when a line where at least two preset current branches are located in a non-synchronous period is disconnected due to a short circuit fault, switching the on-off unit, the corresponding current branch, and the corresponding auxiliary branch unit based on the operating state includes:
when a line where a third preset through-current branch is located has a fault at a first moment, locking the third preset through-current branch so as to enable current to flow to the cut-off branch through a corresponding first auxiliary branch;
a first mechanical switch for opening the third preset through-current branch;
when a line where a fourth preset through-current branch is located has a fault at a second moment, locking the fourth preset through-current branch so that current flows to the cut-off branch through the corresponding first auxiliary branch;
the first mechanical switch is used for opening the fourth preset through-current branch;
the non-synchronization means that the time difference of the occurrence moments of the short-circuit faults of the lines where the at least two preset current branches are located is smaller than the clearing time of a single fault.
According to the control method of the multi-port direct current circuit breaker provided by the embodiment of the invention, when the non-synchronous multi-pole line short circuit fault is cut off, fault clearing and isolation of multi-pole line short circuit continuous faults within a short time interval (ms level) can be realized through the design of the auxiliary branch circuit, and the isolation is carried out by using the diode valve and the shared thyristor valve, so that the equipment cost is greatly reduced.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.
Fig. 1 is a schematic structural diagram of a multi-port dc circuit breaker according to an embodiment of the present invention;
FIGS. 2a and 2c are schematic structural diagrams of a breaking branch according to an embodiment of the present invention;
FIGS. 2b and 2d are schematic diagrams of the current branches according to embodiments of the present invention;
FIGS. 3 a-3 c are schematic structural diagrams of a first auxiliary branch according to an embodiment of the present invention;
FIGS. 4 a-4 c are schematic mechanical views of a second auxiliary branch according to an embodiment of the present invention;
fig. 5 a-5 d are schematic structural views of a power electronic switching unit according to an embodiment of the invention;
FIG. 6 is a schematic structural diagram of a negative pressure coupling switch according to an embodiment of the invention;
fig. 7 a-7 b are schematic structural views of a multi-port dc circuit breaker according to an embodiment of the present invention;
figures 8 a-8 b are schematic diagrams of a multi-port dc circuit breaker commissioning process according to an embodiment of the present invention;
fig. 9 a-9 e are schematic diagrams of the opening process of the multi-port dc breaker in case of short-circuit fault of the line 1 according to the embodiment of the present invention;
10 a-10 e are schematic diagrams of a multi-port DC breaker opening process in the event of a short-circuit fault of a DC bus according to an embodiment of the present invention;
11 a-11 b are schematic diagrams of a multi-port DC circuit breaker opening process upon non-contemporaneous multi-pole fault according to an embodiment of the invention;
12 a-12 b are schematic diagrams of a multi-port DC circuit breaker opening process upon failure of a first mechanical switch according to an embodiment of the present invention;
fig. 13 is a flowchart of a method of controlling a multi-port dc circuit breaker according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The embodiment of the invention provides a multi-port direct current circuit breaker which comprises a breaking unit, at least two through-current branches and at least two auxiliary branch units. The auxiliary branch units are arranged in one-to-one correspondence with the through-flow branches.
As shown in fig. 1, the multi-port dc circuit breaker includes m current branches and m auxiliary branch units, and in this embodiment, no limitation is imposed on the specific value of m, and corresponding setting may be specifically performed according to actual conditions, and it is only necessary to ensure that the current branches and the auxiliary branch units are set in a one-to-one correspondence manner.
Specifically, m direct current lines are led out of the direct current bus, and a through-current branch is arranged on each direct current line. That is, one end of the through-flow branch is connected to the dc bus, and the other end is connected to one end of the cut-off unit through the corresponding auxiliary branch unit. Wherein, the other end of the breaking unit is connected with the direct current bus.
The on-off unit at least comprises a first power electronic switch unit, and other switch units can be combined on the basis of the first power electronic switch unit, and the like, so that specific circuit structures of the first power electronic switch unit and the other switch units are not limited at all, and the on-off unit can be controlled to be on-off correspondingly according to requirements. The first power electronic switch unit can be formed by adopting full-control devices such as IGBT, IGCT, BIGT and IEGT and is used for bearing and turning off load and short-circuit current in a short time. For the convenience of the following description, the first power electronic switching unit is referred to as the main breaker, denoted MB.
The through-current branch at least comprises a first mechanical switch which is used for controlling the on-off of the corresponding line. As shown in fig. 1, the throughflow branches are connected in series on the respective dc lines. In particular, the current branch is used to conduct the load current during normal operation of the dc system.
And two ends of the auxiliary branch unit are respectively connected with the cut-off unit and the through-current branch and are used for assisting in conducting current in the switching-off and switching-on processes and isolating each line after switching-off. As shown in fig. 1, the auxiliary branch unit has a first auxiliary branch and a second auxiliary branch, and the conduction directions of the first auxiliary branch and the second auxiliary branch are opposite. Specifically, the auxiliary branch unit is used for providing a path and voltage isolation between lines for current in the breaking process, the first auxiliary branch (also called as an upper auxiliary branch) is used for conducting the breaking unit to flow current to the direct current line, and the second auxiliary branch (also called as a lower auxiliary branch) is used for conducting the direct current line to flow current to the breaking unit. For convenience of description hereinafter, the first auxiliary branch is referred to as an upper auxiliary branch, and the second auxiliary branch is referred to as a lower auxiliary branch.
Taking the dc line 1 as an example, the corresponding amplitude branch unit has a first auxiliary branch 1 and a second amplitude branch 1, and two ends of the first auxiliary branch 1 and the second auxiliary branch 2 are respectively connected to the cut-off unit and the through-current branch 1.
The multiport direct current circuit breaker that this embodiment provided can make full accuse device use quantity practice thrift more than 50% through the mode of sharing the unit of breaking, and adopts the mode that mechanical switch and power electronic switch unit combine to realize multiport direct current circuit breaker, can realize the line voltage isolation under steady state and the trouble condition of breaking, can reduce the isolation cost to the balance between capacity and the cost of breaking has been guaranteed.
In some optional embodiments of the present embodiment, the disconnection unit includes a disconnection branch and an energy consumption branch connected in parallel, wherein the disconnection branch has a first power electronic switching unit. The on-off branch is used for bearing and switching off load and short-circuit current in short time; the energy consumption branch is used for limiting switching-off overvoltage and absorbing energy.
In particular, the energy consuming branch may comprise a non-linear resistance unit SA connected in parallel across the breaking branch. One end of the energy consumption branch and one end of the cut-off branch are connected with the direct current bus, and the other ends of the energy consumption branch and the cut-off branch are connected with the corresponding direct current circuit through the upper auxiliary branch and the lower auxiliary branch respectively and then are connected with two ends of the through current branch in parallel.
In the present exemplary embodiment, 2 alternative embodiments are provided for the disconnection branch and the current branch. Specifically, scheme 1: as shown in fig. 2a, the open branch has a first power electronic switching unit, i.e. MB; as shown in fig. 2b, the current-carrying branch comprises a second power electronic switching unit (i.e. LCS) in series with the first mechanical switch (i.e. UFD). Wherein the second power electronic switching unit may also be referred to as a current transfer switching unit.
Scheme 2: as shown in fig. 2c, the open branch comprises a first power electronic switching unit MB and a negative voltage coupling switch CNV connected in series; as shown in fig. 2d, the current branch has a first mechanical switch, which is denoted MS in fig. 2d for the purpose of distinguishing it from the first mechanical switch in fig. 2 b.
In the scheme 1, the current branch comprises a first mechanical switch UFD and a current transfer switch LCS connected in series, and the breaking branch is composed of a main circuit breaker MB composed of fully-controlled power electronic switch units. In the scheme 2, the through-current branch comprises a first mechanical switch MS, and the open-close branch is formed by connecting a main circuit breaker MB formed by a full-control power electronic switch unit and a negative-pressure coupling switch CNV in series.
Specifically, scheme 1 forces the current to be diverted to the disconnect branch using a current transfer disconnect LCS to latch the set-up voltage during the disconnect process. Scheme 2 mainly plays the effect of transfer current through the negative pressure coupling unit, utilizes its inductive discharge to pour into reverse current to the through-current branch road, forces the current to shift to the branch road of breaking, compares with scheme 1, and the through-current branch road in scheme 2 only has mechanical switch, and the conduction loss can be approximately neglected, has reduced the running cost of circuit breaker.
In some optional embodiments of this embodiment, the auxiliary branch unit comprises a third power electronic switch unit or a diode unit. That is, the auxiliary branch unit may form the third power electronic switch unit through various power electronic switches, or may form the diode unit through a combination of a plurality of diodes, and the specific structure of the auxiliary branch unit is not limited in this embodiment, and may be specifically set according to an actual situation.
Each auxiliary branch unit can independently cut off short-circuit current of each line, and the device has the capacity of simultaneously cutting off short-circuit faults of multiple outgoing lines and clearing faults of the direct-current bus.
The third power electronic switch unit may also include a first power electronic switch and a unidirectional main flow switch connected in series; or a second power electronic switch connected in series.
The diode unit may also include a first diode connected in series in sequence, or may include at least two diode branches connected in parallel and a fourth power electronic switch, where the fourth power electronic switch is connected in series with the at least two diode branches connected in parallel.
Based on this, the present embodiment proposes the structure of the upper and lower auxiliary branches in 3. Wherein, fig. 3 a-3 c show the structural schematic diagram of the upper auxiliary branch, and fig. 4 a-4 c show the structural schematic diagram of the lower auxiliary branch.
For the upper auxiliary branch, scheme 1: the system comprises a unidirectional choke switch UCBS and a first power electronic switch which are connected in series, wherein the first power electronic switch can be an auxiliary valve T;
scheme 2: the second power electronic switch is connected in series in sequence, and the second power electronic switch can adopt an auxiliary valve T;
scheme 3: the first diode is connected in series in sequence, and the first diode can adopt an auxiliary valve D.
For the lower auxiliary leg, scheme 1: the system comprises a unidirectional choke switch UCBS and a first power electronic switch which are connected in series, wherein the first power electronic switch can be an auxiliary valve T;
scheme 2: the second power electronic switch is connected in series in sequence, and the second power electronic switch can adopt an auxiliary valve T;
scheme 3: the power supply comprises a plurality of diode branches and a fourth power electronic switch which are connected in parallel, wherein the fourth power electronic switch is connected with the plurality of diode branches which are connected in parallel in series. The fourth power electronic switch may also adopt a common auxiliary valve T, and the diode in the diode branch may adopt an auxiliary valve D.
It should be noted here that, in case 1 in both the upper auxiliary branch and the lower auxiliary branch, the first power electronic switch is included, but the two first power electronic switches in the upper and lower auxiliary branches may be the same or different.
Likewise, for scenario 2 in both the upper and lower auxiliary branches, a second power electronic switch is included, but the two second power electronic switches in the upper and lower auxiliary branches may be the same or different.
In some optional embodiments of this embodiment, the main breaker MB and the second power electronic switch unit LCS may be formed by cascading the power electronic switch units shown in fig. 5a to 5d, and the power electronic switch units may adopt fully-controlled devices such as IGBT, IGCT, BIGT, IEGT, and the like.
As shown in fig. 6, the negative voltage coupling unit includes a coupling reactor, a capacitor, and a third power electronic switch. The third power electronic switch can be realized by a thyristor valve and can also be realized by other power electronic switches. In particular, the secondary side CR of the coupling reactorCNVConnected in series with main relay MB to be switched offIn the branch, primary side TCNVAnd a capacitor CCNVThyristor valve TCNVAre connected in series to form a discharge loop. When the pre-charging of the capacitor reaches a target voltage value, a thyristor valve is triggered in the on-off process of the circuit breaker, the capacitor and the primary side of the coupling reactor form an oscillating discharge loop to generate discharge current, the secondary side reacts negative pressure and simultaneously generates current, reverse current is injected into the through-flow branch to enable the current of the first mechanical switch MS to be zero-cross on-off, and the current is assisted to be transferred to the on-off branch.
In some specific applications of this embodiment, taking two dc lines as an example, the current branch adopts the structure shown in fig. 2a, and the cut-off branch adopts the structure shown in fig. 2b, where MB and LCS are based on the diode full-bridge sub-module topology shown in fig. 5d, the upper auxiliary branch adopts the structure shown in fig. 3c, and the lower auxiliary branch adopts the structure shown in fig. 4 c. Based on this structure, the structure of the resulting multi-port dc circuit breaker is shown in fig. 7 a.
In other specific applications of this embodiment, taking two dc lines as an example, the current branch adopts the structure shown in fig. 2c, and the cut-off branch adopts the structure shown in fig. 2d, where MB and LCS are based on the diode full-bridge submodule topology in fig. 5d, the upper auxiliary branch adopts the structure shown in fig. 3c, and the lower auxiliary branch adopts the structure shown in fig. 4 c. Based on this structure, the structure of the resulting multi-port dc circuit breaker is shown in fig. 7 b.
Compared with a single hybrid breaker scheme, the method for sharing the main breaker in the multi-port direct current breaker provided by the embodiment of the invention saves the using quantity of the full-control devices by more than 50%; furthermore, the voltage isolation between lines under the working conditions of steady state and fault breaking is realized by utilizing the unidirectional high-voltage thyristor valve and the low-voltage diode valve, the isolation cost is greatly reduced, and the overall cost is saved by at least more than 40% compared with the scheme of adopting an independent single hybrid direct-current circuit breaker. An embodiment of the present invention further provides a control method based on the foregoing multi-port dc circuit breaker, as shown in fig. 13, the control method includes:
and S11, acquiring the working state of the multi-port direct current breaker.
The working states of the multi-port direct current circuit breaker comprise operation, line short-circuit fault disconnection, direct current bus short-circuit fault disconnection, failure of a first mechanical switch in a short-circuit fault disconnected through-current branch and the like. The working state of the multi-port direct current circuit breaker can be automatically monitored or monitored by other equipment.
S12, switching the on-state of the disconnection unit, the corresponding current branch and the corresponding auxiliary branch unit based on the operation state.
The multi-port direct current circuit breaker switches the conduction states of the switching-on/off unit, the corresponding through-current branch circuit and the auxiliary branch circuit unit according to different working states of the multi-port direct current circuit breaker.
According to the control method of the multi-port direct current circuit breaker, the working state of the multi-port direct current circuit breaker is monitored, and the conducting states of each cut-off unit, the through-current branch circuit and the auxiliary branch circuit unit are correspondingly controlled according to the monitoring result, so that the short-circuit current can be rapidly transferred, limited and cut-off, and the cut-off current can reach dozens of kA.
When the multi-port dc breaker is put into operation, the step S12 includes:
(1) switching on a switching-off branch in the switching-off unit so as to enable current to flow through the switching-off unit;
(2) when a closing judgment condition is met, a first mechanical switch in the through-flow branch is closed, so that current flows from the through-flow branch.
Specifically, taking the multi-port dc breaker shown in fig. 7a as an example, the multi-port dc breaker is put into operation:
before the dc breaker is put into operation, the main breaker MB is switched on and the current flows through the breaking branch, as shown in fig. 8 a; after the switching-on judgment condition is met, a mechanical switch UFD of the through-flow branch is switched on, and a current transfer switch LCS is switched on; after the UFD is switched on, the load current flows through the through-current branch, as shown in fig. 8b, the multi-port dc circuit breaker is put into operation.
To better illustrate the faults involved in the embodiments of the present invention, the following are described here:
(1) single line failure: short circuit fault of single direct current line;
(2) fault of direct current bus: short circuit fault of the direct current bus;
(3) simultaneous multi-line fault: more than 1 common bus direct current lines have faults simultaneously, and the action principle is switched off along with the fault of a single line corresponding to more than 1 through current branch circuits acting simultaneously;
(4) asynchronous line fault: more than 1 common bus direct current line has faults, and the fault time difference is smaller than the fault clearing time of a single line, namely, the subsequent faults still occur in the clearing process of the previous fault, and the action principle of the subsequent faults is different from that of the faults of multiple lines in the same period;
(5) fault clearance under failsafe: a fault occurs in the dc line and the first mechanical switch of the corresponding through-current branch fails.
When a fault occurs on the line side of the dc circuit breaker, that is, when the predetermined line short-circuit fault is open, taking a single-pole line fault as an example, the step S12 includes:
(1) switching on a switching unit in the switching-off branch and locking a first preset through-current branch corresponding to the preset line so as to force current to be transferred to the switching-off branch and the first auxiliary branch;
(2) when the current of the first preset through-current branch passes through zero, a first mechanical switch in the first preset through-current branch is switched off;
(3) latching the open branch and charging a capacitor in the open branch to transfer the current to the energy consuming branch;
(4) and when the voltage of the energy consumption branch circuit is higher than that of the multi-port direct current circuit breaker, the current of the first preset through current branch circuit is switched on and off.
Specifically, taking the multi-port dc circuit breaker shown in fig. 7a as an example, when the dc line 1 is disconnected due to a short-circuit fault, the multi-port dc circuit breaker receives a disconnection command or an overcurrent protection action, turns on the disconnection branch MB, and locks the LCS1 in the current branch 1 to force the current to be transferred to the disconnection branch, as shown in fig. 9 a; after the current of the current branch 1 crosses zero, the current is fed to the short-circuit point through the diode valve of the cut-off branch MB and the upper current branch 1, and the UFD1 is opened to achieve the voltage-resistant open distance, as shown in fig. 9 b; after the UFD1 reaches the withstand voltage separation distance, the main breaker MB is closed, the current charges the capacitor in the full bridge module, as shown in fig. 9c, the voltage rises to the parallel MOV, and the current is transferred to the MOV for circulation, as shown in fig. 9 d; when the MOV voltage is higher than the system dc voltage, the short circuit current continuously drops to zero crossing, the circuit breaker completes the current breaking, and the current branch UFD1 and the breaking branch MB and the corresponding auxiliary switches isolate the faulty line, as shown in fig. 9 e.
After the breaker is opened, the breaker can be quickly reclosed according to the requirements of a power grid system, and the reclosing operation process is similar to the closing process.
When the same-phase multi-pole line fault occurs on the line side of the direct current breaker, namely when a plurality of line short-circuit faults are on and off at the same time, the control method is the same as the control principle of the single-pole line fault. Specifically, the same principle of the preset line short-circuit fault disconnection control as described above is different in that a plurality of failed lines are controlled simultaneously in the case of a simultaneous multi-line fault. For details, please refer to the above description, which is not repeated herein.
When the dc bus short-circuit fault is open, S12 includes:
(1) switching on a switching unit in the switching-off branch and locking each through-current branch to force current to be transferred to the switching-off branch and the second auxiliary branch;
(2) when the current of each current branch passes through zero, a first mechanical switch in each current branch is switched off;
(3) latching the open branch and charging a capacitor in the open branch to transfer the current to the energy consuming branch;
(4) and when the voltage of the energy consumption branch circuit is higher than that of the multi-port direct current circuit breaker, the current of each through-current branch circuit is switched on and off.
Specifically, taking the multi-port dc circuit breaker shown in fig. 7a as an example, the principle of breaking when the power supply side of the dc circuit breaker fails is the same as the principle of breaking when the line side fails, except that the lower auxiliary valve Tl needs to be turned on to provide a path for short-circuit current during the breaking process, which is shown in fig. 10a to 10 e.
Further, when the line in which the second predetermined current branch is located is short-circuited and the first mechanical switch in the second predetermined current branch fails, the step S12 includes:
(1) keeping the second preset current branch on, and conducting the second auxiliary branch;
(2) latching the other current branches and the first auxiliary branch to force current to be transferred to the second preset current branch and the second auxiliary branch;
(3) when the current of the rest of the through-current branches passes through zero, the first mechanical switches of the rest of the through-current branches are switched off and the cut-off branches are locked, so that the isolation of the rest of the through-current branches is completed.
Specifically, taking the multi-port dc circuit breaker shown in fig. 7a as an example, taking the first mechanical switch UFD1 in line 1 as an example of failure and short-circuit fault in line 1 as an example, UFD1 cannot be opened due to the fault during the opening process, as shown in fig. 11 a. And keeping the LCS1 conductive, and triggering the lower auxiliary valve Tl, the locking LCS2 and the one-way choke switch UCBS 1. The current is transferred to the lower auxiliary valve Tl-MB-through-flow branch 1 for circulation, UFD2 is opened after the current of the through-flow branch 2 crosses zero, and MB is locked after UFD2 is opened in place, and the line 2 is isolated, as shown in fig. 11 b. The UFD malfunction protection function ensures that a multiport circuit breaker can effectively isolate a sound line after UFD malfunction.
When the line short-circuit fault where the at least two preset current branches are located is disconnected in the non-synchronous period, where the non-synchronous period is that a time difference between occurrence moments of the line short-circuit fault where the at least two preset current branches are located is smaller than clearing time of a single fault, that is, a subsequent fault still occurs in a clearing process of a previous fault, S12 includes:
(1) when a line where a third preset through-current branch is located has a fault at a first moment, locking the third preset through-current branch so as to enable current to flow to the cut-off branch through a corresponding first auxiliary branch;
(2) a first mechanical switch for opening the third preset through-current branch;
(3) when a line where a fourth preset through-current branch is located has a fault at a second moment, locking the fourth preset through-current branch so that current flows to the cut-off branch through the corresponding first auxiliary branch;
(4) and the first mechanical switch of the fourth preset through-current branch is switched off.
Specifically, also taking the multi-port dc circuit breaker shown in fig. 7a as an example, if the pole line 1 is shorted to ground at time 0, LCS1 is locked, and the current flows through the open branch, so the UFD1 is switched off. At the time of + δ T, the pole line 2 is grounded and shorted, as shown in fig. 12a, at this time, the LCS2 is locked only according to the conventional breaking process, and the UFD2 is switched off after the current of the current branch 2 crosses zero, as shown in fig. 12b, the breaking is completed after the breaking branch MB is locked. The fault clearing and isolation of the multipolar line short circuit continuous fault in a short time interval (ms level) can be realized through the design of the auxiliary branch circuit, and the isolation is carried out by utilizing a diode valve and a shared thyristor valve, so that the equipment cost is greatly reduced.
It should be noted that the line in which the current branch is located refers to the dc line to which the current branch is connected.
Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations fall within the scope defined by the appended claims.
Claims (14)
1. A multi-port dc circuit breaker, comprising:
the switching-off unit is connected with the direct current bus at one end and at least comprises a first power electronic switch unit;
one end of each through-current branch is connected with the direct-current bus, each through-current branch at least comprises a first mechanical switch, and each through-current branch is used for controlling the on-off of a corresponding line;
the auxiliary branch units are provided with the auxiliary branch units which correspond to the through-current branches one by one, two ends of each auxiliary branch unit are respectively connected with the other end of the cut-off unit and the other end of the through-current branch, and the auxiliary branch units are used for assisting in conducting current and isolating each line after switching-off in the switching-off and switching-on processes; the auxiliary branch unit is provided with a first auxiliary branch and a second auxiliary branch, and the conduction directions of the first auxiliary branch and the second auxiliary branch are opposite.
2. The multi-port dc circuit breaker according to claim 1, wherein the breaking unit comprises a breaking branch and a power consuming branch in parallel, wherein the breaking branch has the first power electronic switching unit;
the through-current branch further comprises a second power electronic switching unit in series with the first mechanical switch.
3. The multi-port dc circuit breaker according to claim 1, wherein the breaking unit comprises a breaking branch and a power consuming branch in parallel, wherein the breaking branch further comprises a negative voltage coupling switch in series with the first power electronic switching unit;
the current branch has the first mechanical switch.
4. The multi-port dc circuit breaker of claim 3, wherein the negative coupling switch comprises: the capacitor is connected with the third power electronic switch in series and then connected with the primary side of the coupling reactor in series, and the secondary side of the coupling reactor is connected with the first power electronic switch unit in series.
5. The multi-port dc circuit breaker according to claim 3, wherein the energy dissipating branch comprises a non-linear resistance unit.
6. The multi-port dc circuit breaker according to any of claims 1-3, wherein the auxiliary branch unit comprises: a third power electronic switching unit or diode unit.
7. The multi-port dc circuit breaker according to claim 6, wherein the third power electronic switching unit comprises:
the first power electronic switch and the one-way choke switch are connected in series;
or the like, or, alternatively,
and the second power electronic switches are connected in series in sequence.
8. The multi-port dc circuit breaker according to claim 6, wherein the diode unit comprises:
a first diode connected in series in sequence;
or the like, or, alternatively,
the diode unit includes:
at least two diode branches connected in parallel;
a fourth power electronic switch in series with the at least two diode branches after parallel connection.
9. A control method for a multi-port dc circuit breaker, for use in a multi-port dc circuit breaker according to any of claims 1-8, the control method comprising:
acquiring the working state of the multi-port direct current circuit breaker;
and switching the conduction states of the cut-off unit, the corresponding current branch circuit and the corresponding auxiliary branch circuit unit based on the working state.
10. The control method according to claim 9, wherein switching the conduction states of the breaking unit, the corresponding current branch and the corresponding auxiliary branch unit based on the operating state when the multi-port dc circuit breaker is put into operation includes:
switching on a switching-off branch in the switching-off unit so as to enable current to flow through the switching-off unit;
when a closing judgment condition is met, a first mechanical switch in the through-flow branch is closed, so that current flows from the through-flow branch.
11. The control method according to claim 9, wherein said switching the conduction state of the breaking unit, the respective current branch and the respective auxiliary branch unit based on the operating state when at least one preset line short-circuit fault of the multi-port dc circuit breaker is broken comprises:
switching on a switching unit in the switching-off branch and locking a first preset through-current branch corresponding to the at least one preset line so as to force current to be transferred to the switching-off branch and the first auxiliary branch;
when the current of the at least one first preset current branch passes through zero, a first mechanical switch in the at least one first preset current branch is switched off;
latching the open branch and charging a capacitor in the open branch to transfer the current to the energy consuming branch;
and when the voltage of the energy consumption branch circuit is higher than the voltage of the multi-port direct current circuit breaker, the current of the at least one first preset current branch circuit is switched on and off.
12. The control method according to claim 9, wherein switching the conduction states of the disconnection unit, the corresponding current branch circuit, and the corresponding auxiliary branch circuit unit based on the operating state when the dc bus short-circuit fault is disconnected comprises:
switching on a switching unit in the switching-off branch and locking each through-current branch to force current to be transferred to the switching-off branch and the second auxiliary branch;
when the current of each current branch passes through zero, a first mechanical switch in each current branch is switched off;
latching the open branch and charging a capacitor in the open branch to transfer the current to the energy consuming branch;
and when the voltage of the energy consumption branch circuit is higher than that of the multi-port direct current circuit breaker, the current of each through-current branch circuit is switched on and off.
13. The method according to claim 9, wherein switching the on-state of the disconnection unit, the corresponding current branch and the corresponding auxiliary branch unit based on the operating state when a line in which a second predetermined current branch is located is short-circuited and the first mechanical switch in the second predetermined current branch fails comprises:
keeping the second preset current branch on, and conducting the second auxiliary branch;
latching the other current branches and the first auxiliary branch to force current to be transferred to the second preset current branch and the second auxiliary branch;
when the current of the rest of the through-current branches passes through zero, the first mechanical switches of the rest of the through-current branches are switched off and the cut-off branches are locked, so that the isolation of the rest of the through-current branches is completed.
14. The control method according to claim 9, wherein when a line short-circuit fault of at least two predetermined current branches is disconnected, the switching the conduction states of the disconnection unit, the corresponding current branch, and the corresponding auxiliary branch unit based on the operating state comprises:
when a line where a third preset through-current branch is located has a fault at a first moment, locking the third preset through-current branch so as to enable current to flow to the cut-off branch through a corresponding first auxiliary branch;
a first mechanical switch for opening the third preset through-current branch;
when a line where a fourth preset through-current branch is located has a fault at a second moment, locking the fourth preset through-current branch so that current flows to the cut-off branch through the corresponding first auxiliary branch;
the first mechanical switch is used for opening the fourth preset through-current branch;
and the non-synchronization means that the time difference of the occurrence moments of the short-circuit faults of the lines where the at least two preset through-current branches are located is less than the clearing time of a single fault.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110214718.0A CN112865040A (en) | 2021-02-25 | 2021-02-25 | Multi-port direct current circuit breaker and control method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110214718.0A CN112865040A (en) | 2021-02-25 | 2021-02-25 | Multi-port direct current circuit breaker and control method thereof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN112865040A true CN112865040A (en) | 2021-05-28 |
Family
ID=75991687
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110214718.0A Pending CN112865040A (en) | 2021-02-25 | 2021-02-25 | Multi-port direct current circuit breaker and control method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112865040A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114156846A (en) * | 2021-12-02 | 2022-03-08 | 中国科学院电工研究所 | Low-loss multi-terminal direct current circuit breaker and control method thereof |
| CN114172135A (en) * | 2021-12-15 | 2022-03-11 | 天津大学 | Double-main-breaking type multi-port hybrid direct-current circuit breaker applicable to multi-terminal direct-current power grid |
| CN114336547A (en) * | 2021-12-28 | 2022-04-12 | 全球能源互联网研究院有限公司 | Capacitor self-energy-taking auxiliary turn-off hybrid direct current breaker and application method thereof |
-
2021
- 2021-02-25 CN CN202110214718.0A patent/CN112865040A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114156846A (en) * | 2021-12-02 | 2022-03-08 | 中国科学院电工研究所 | Low-loss multi-terminal direct current circuit breaker and control method thereof |
| CN114172135A (en) * | 2021-12-15 | 2022-03-11 | 天津大学 | Double-main-breaking type multi-port hybrid direct-current circuit breaker applicable to multi-terminal direct-current power grid |
| CN114172135B (en) * | 2021-12-15 | 2023-10-27 | 天津大学 | Double-main-break type multi-port hybrid direct current breaker applicable to multi-port direct current power grid |
| CN114336547A (en) * | 2021-12-28 | 2022-04-12 | 全球能源互联网研究院有限公司 | Capacitor self-energy-taking auxiliary turn-off hybrid direct current breaker and application method thereof |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN103972855B (en) | A kind of device making circuit bidirectional current disjunction and control method thereof | |
| CN107645154B (en) | Novel combined direct current circuit breaker and application method thereof | |
| CN103972875B (en) | Limit line current or make device and the control method thereof of electric current disjunction | |
| CN106207953B (en) | High-power hybrid direct current circuit breaker | |
| CN112865040A (en) | Multi-port direct current circuit breaker and control method thereof | |
| CN110021919B (en) | Intensive bridge type multi-port hybrid direct-current circuit breaker and control method | |
| CN109873407B (en) | Annular bridge type multi-port hybrid direct-current circuit breaker | |
| CN109687405B (en) | Multiport combined type hybrid direct current circuit breaker and control method | |
| CN110970875A (en) | Combined current-limiting type direct current breaker for direct current power grid | |
| CN114172135B (en) | Double-main-break type multi-port hybrid direct current breaker applicable to multi-port direct current power grid | |
| CN208433908U (en) | Voltage source converter module and inverter | |
| CN108322056A (en) | A kind of Modular HVDC converting means and its control method | |
| CN113422360A (en) | Direct current breaker and control method | |
| CN103971965A (en) | Line current breaking device and control method thereof | |
| CN109217239B (en) | Direct current breaker with breaking selection function | |
| CN214314555U (en) | Multiport direct current breaker | |
| CN214314552U (en) | Multifunctional multiport hybrid direct current breaker | |
| CN112865046A (en) | Multifunctional multiport hybrid direct current breaker and control method | |
| CN114336550B (en) | Self-energy-taking multi-port direct current breaker and application method | |
| CN214314550U (en) | Multi-port direct current circuit breaker | |
| CN114421420B (en) | Resistance sensing type current-limiting multi-port direct current breaker suitable for flexible direct current distribution network | |
| CN111900703B (en) | Hybrid direct current breaker | |
| CN114597872B (en) | DC circuit breaker, control method thereof and electronic equipment | |
| CN113852056A (en) | Economical direct current breaker with pre-current limiting function and control method thereof | |
| CN112865047A (en) | Multi-port direct current breaker and application method thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |