CN111244905A - Direct-current circuit breaker reclosing method and system based on voltages at two ends of circuit breaker - Google Patents
Direct-current circuit breaker reclosing method and system based on voltages at two ends of circuit breaker Download PDFInfo
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- CN111244905A CN111244905A CN202010042243.7A CN202010042243A CN111244905A CN 111244905 A CN111244905 A CN 111244905A CN 202010042243 A CN202010042243 A CN 202010042243A CN 111244905 A CN111244905 A CN 111244905A
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- 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
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/02—Details
- H02H3/06—Details with automatic reconnection
- H02H3/066—Reconnection being a consequence of eliminating the fault which caused disconnection
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- 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
- H02H7/261—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 involving signal transmission between at least two stations
- H02H7/262—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 involving signal transmission between at least two stations involving transmissions of switching or blocking orders
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Abstract
The invention discloses a reclosing method and a reclosing system of a direct current circuit breaker based on voltages at two ends of the circuit breaker, and belongs to the technical field of power systems and automation of the power systems. The method comprises the following steps: carrying out fault detection on the direct current transmission system, and controlling a mechanical switch to be switched off after the direct current breaker of the direct current transmission system is determined to be switched off and the residual current of the direct current breaker disappears when the direct current breaker of the direct current transmission system is determined to be in fault; after the preset time after the mechanical switch is switched off is determined, whether the fault point of the fault is dissociated is judged, and when the fault point of the transient fault is dissociated, the mechanical switch is switched on; and measuring the voltages at the two ends of the direct current breaker in real time, if the voltages at the two ends of the direct current breaker are attenuated continuously and are lower than the direct current voltage of the direct current transmission system, determining that the fault is an instantaneous fault, and reclosing the direct current breaker of the direct current transmission system. The invention improves the accuracy and reliability of the reclosing of the direct-current circuit breaker of the direct-current power transmission system.
Description
Technical Field
The invention relates to the technical field of power systems and automation thereof, in particular to a reclosing method and system of a direct current circuit breaker based on voltages at two ends of the circuit breaker.
Background
The traditional power grid commutation Converter high voltage Direct Current (LCC-HVDC) has the advantages of low manufacturing cost, small loss, high reliability and the like, is widely applied to occasions such as submarine cable power transmission, large-capacity long-distance power transmission, asynchronous power grid interconnection and the like at present, and has the defects of large reactive compensation capacity requirement, strong alternating Current system dependence, commutation failure and the like objectively. Compared with LCC-HVDC, the Voltage Source Converter based high Voltage Direct Current (VSC-HVDC) adopting the full-control device can realize four-quadrant independent control of active power and reactive power, does not need an alternating Current system to provide phase change support, does not have the problem of phase change failure, has certain difference with LCC-HVDC in rated Voltage and transmission power, and has high investment and construction cost and larger loss. The transmission system with the transmission end adopting the LCC and the receiving end adopting the LCC and the VSC in series-parallel connection is a typical hybrid cascade multi-end direct-current transmission system, provides a more flexible and rapid transmission mode, improves the voltage stability of an alternating-current system at the inversion side, reduces the probability of phase change failure, can give consideration to economic and technical benefits, and is one of important development directions of future extra-high voltage direct-current transmission technology.
The operation experience shows that the overhead line fault of the power system has the characteristics of single phase (polarity) and instantaneity, the circuit breaker trips after the fault, the probability of the circuit breaker reclosing success after the arc extinction at the fault point is 60% -90%, the higher the voltage grade is, the higher the reclosing success rate is, and as the hybrid cascade multi-terminal direct-current power transmission system adopts the overhead power transmission line, the reclosing technology is of great importance for improving the operation reliability of the hybrid cascade multi-terminal direct-current power transmission system. However, if the fault is superposed on a permanent fault, the power system will suffer two times of fault impact in a short time, which will destroy the stability of the system, and will reduce the insulation level of the electrical equipment and reduce the service life thereof. Due to the vulnerability of the power electronic device, compared with an alternating current system, the mixed cascade multi-terminal direct current transmission system has poorer fault impact bearing capability, and how to accurately judge the fault property and adaptively adjust the reclosing time to reduce the fault impact is the key point of the reclosing technology of the mixed cascade multi-terminal direct current transmission system.
Disclosure of Invention
Aiming at the problems, the invention provides a reclosing method of a direct current breaker based on voltages at two ends of the breaker, which comprises the following steps:
carrying out fault detection on the direct current transmission system, and controlling a mechanical switch to be switched off after the direct current breaker of the direct current transmission system is determined to be switched off and the residual current of the direct current breaker disappears when the direct current breaker of the direct current transmission system is determined to be in fault;
after the preset time after the mechanical switch is switched off is determined, whether the fault point of the fault is dissociated is judged, and when the fault point of the transient fault is dissociated, the mechanical switch is switched on;
and measuring the voltages at the two ends of the direct current breaker in real time, if the voltages at the two ends of the direct current breaker are attenuated continuously and are lower than the direct current voltage of the direct current transmission system, determining that the fault is an instantaneous fault, and reclosing the direct current breaker of the direct current transmission system.
Optionally, the method further comprises:
and if the voltages at the two ends of the direct current breaker are kept within the preset threshold value, determining the permanent fault of the fault, and not reclosing the direct current breaker of the direct current transmission system.
Optionally, the preset time is 200 ms.
Optionally, the preset threshold is 390-410 kV.
Optionally, the method further comprises: and after the direct-current circuit breaker of the direct-current transmission system is reclosed, determining whether the pole power of the direct-current circuit breaker is recovered to the power level before the fault, and if the pole power of the direct-current circuit breaker is not recovered to the power level before the fault, performing fault detection on the direct-current transmission system again.
The invention also provides a reclosing system of the direct current circuit breaker based on the voltages at two ends of the circuit breaker, which comprises the following components:
the first control module is used for carrying out fault detection on the direct current transmission system, and controlling the mechanical switch to be switched off after the direct current breaker of the direct current transmission system is determined to be switched off and the residual current of the direct current breaker disappears when the direct current breaker of the direct current transmission system is determined to be in fault;
the second control module is used for determining whether the fault point of the fault is dissociated after the preset time after the mechanical switch is switched off, and switching on the mechanical switch after the dissociation of the fault point of the transient fault is determined;
and the third control module is used for measuring the voltages at the two ends of the direct current circuit breaker in real time, determining that the fault is an instantaneous fault if the voltages at the two ends of the direct current circuit breaker are continuously attenuated and are lower than the direct current voltage of the direct current transmission system, and reclosing the direct current circuit breaker of the direct current transmission system.
Optionally, the third control module is further configured to:
and if the voltages at the two ends of the direct current breaker are kept within the preset threshold value, determining the permanent fault of the fault, and not reclosing the direct current breaker of the direct current transmission system.
Optionally, the preset time is 200 ms.
Optionally, the preset threshold is 390-410 kV.
Optionally, the third control module is further configured to: and after the direct-current circuit breaker of the direct-current transmission system is reclosed, determining whether the pole power of the direct-current circuit breaker is recovered to the power level before the fault, and if the pole power of the direct-current circuit breaker is not recovered to the power level before the fault, performing fault detection on the direct-current transmission system again.
According to the invention, the reclosing time of the direct current breaker is adaptively adjusted according to the voltage at the two ends of the main breaker after the mechanical switch is closed, so that the accuracy and the reliability of reclosing are improved.
Drawings
FIG. 1 is a flow chart of a reclosing method of a DC circuit breaker based on voltages at two ends of the circuit breaker according to the present invention;
FIG. 2 is a diagram of equivalent circuits of voltages at two ends of a direct current breaker during transient faults in a reclosing method of the direct current breaker based on voltages at two ends of the breaker;
FIG. 3 is a diagram of equivalent circuits of voltages at two ends of a DC circuit breaker in permanent faults of the reclosing method of the DC circuit breaker based on the voltages at two ends of the circuit breaker;
fig. 4 is a topological structure diagram of a combined dc circuit breaker suitable for hybrid cascade multi-terminal dc power transmission according to a dc circuit breaker reclosing method based on voltages at two ends of the circuit breaker;
fig. 5 is a schematic diagram of a configuration scheme of a combined dc circuit breaker in a hybrid cascade multi-terminal dc power transmission system according to a dc circuit breaker reclosing method based on voltages at two ends of the circuit breaker of the present invention;
fig. 6 is a control timing diagram of a instantaneous fault combined dc circuit breaker according to a dc circuit breaker reclosing method based on voltages at two ends of the circuit breaker;
fig. 7 is a control timing diagram of a permanent fault combined dc circuit breaker according to a dc circuit breaker reclosing method based on voltages at two ends of the circuit breaker;
fig. 8 is a graph showing a current curve flowing through a mechanical switch after the mechanical switch is closed according to an embodiment of a reclosing method of a direct current circuit breaker based on voltages at two ends of the circuit breaker;
fig. 9 is a line voltage curve diagram of an embodiment of a reclosing method of a direct current circuit breaker based on voltages at two ends of the circuit breaker in the case of an instantaneous fault according to the invention;
FIG. 10 is a line voltage curve diagram of a permanent fault in an embodiment of a method for reclosing a DC circuit breaker based on voltages at two ends of the circuit breaker according to the present invention;
fig. 11 is a structural diagram of a reclosing system of a dc circuit breaker based on voltages at two ends of the circuit breaker according to the present invention.
Detailed Description
The exemplary embodiments of the present invention will now be described with reference to the accompanying drawings, however, the present invention may be embodied in many different forms and is not limited to the embodiments described herein, which are provided for complete and complete disclosure of the present invention and to fully convey the scope of the present invention to those skilled in the art. The terminology used in the exemplary embodiments illustrated in the accompanying drawings is not intended to be limiting of the invention. In the drawings, the same units/elements are denoted by the same reference numerals.
Unless otherwise defined, terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Further, it will be understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense.
The invention provides a reclosing method of a direct current circuit breaker based on voltages at two ends of the circuit breaker, which comprises the following steps of:
carrying out fault detection on the direct current transmission system, and controlling a mechanical switch to be switched off after the direct current breaker of the direct current transmission system is determined to be switched off and the residual current of the direct current breaker disappears when the direct current breaker of the direct current transmission system is determined to be in fault;
after 200ms after the mechanical switch is switched off, determining whether the fault point of the fault is dissociated and is finished, and switching on the mechanical switch after the fault point of the transient fault is dissociated and is determined to be dissociated and finished;
and measuring the voltages at the two ends of the direct current breaker in real time, if the voltages at the two ends of the direct current breaker are attenuated continuously and are lower than the direct current voltage of the direct current transmission system, determining that the fault is an instantaneous fault, and reclosing the direct current breaker of the direct current transmission system.
And if the voltage at the two ends of the direct current breaker is kept within 390-410kV, determining the permanent fault of the fault, and not reclosing the direct current breaker of the direct current transmission system.
And after the direct-current circuit breaker of the direct-current transmission system is reclosed, determining whether the pole power of the direct-current circuit breaker is recovered to the power level before the fault, and if the pole power of the direct-current circuit breaker is not recovered to the power level before the fault, performing fault detection on the direct-current transmission system again.
The principle of the invention is as follows:
as shown in fig. 2, when a transient fault occurs in a dc circuit breaker of a hybrid cascade multi-terminal dc power transmission system, the dc circuit breaker is turned off rapidly, after the residual current disappears, a mechanical switch K _2 is switched off, and at this time, dc voltage is applied across the mechanical switch K _2, a fault point starts to be dissociated, and if K _2 is switched on during the dissociation removal period, the dc voltage is immediately applied to the fault point, which may cause a reignition of the fault point, so that the mechanical switch K _2 is switched on after the dissociation is ensured, the combined circuit breaker is equivalent to a uF-level capacitor C1, the fault point is equivalent to a nF-level capacitor C2, and according to the circuit principle, the total voltage across the series circuit of capacitors is equal to the sum of the divided voltages across the capacitors, that is U1+ U2+ U3+ … + Un. When the capacitors are connected in series, the distributed voltage of each capacitor is inversely proportional to the capacitance, namely Un is Q/Cn (because the charge quantity of each capacitor in the capacitor series circuit is equal, the distributed voltage of the capacitor with larger capacitance is lower, and the distributed voltage of the capacitor with smaller capacitance is higher), so that after the mechanical switch K _2 is switched on, the LCC and the VSC system charge the two equivalent capacitors, after the charging is finished, the line voltage is almost the same as the VSC outlet voltage, the left main circuit breaker and the right main circuit breaker do not bear the voltage any more, and most of the voltage is borne by a fault point.
Similarly, when a permanent fault occurs, the mechanical switch K _2 is switched on after the trip time, as shown in fig. 3, since the voltages at the two ends of the fault point are 0, the voltages of the LCC and the VSC system are all borne by the combined type direct current circuit breaker, and since the main circuit breaker is not switched on, the fault point can not be ignited at the moment.
After the dissociation time is over, the mechanical switch K _2 is closed, the voltage at two ends of the direct current breaker is measured, if the voltage at two ends of the direct current breaker is continuously attenuated to be lower than the direct current voltage of the system, the transient fault is judged, and CCP can be switched on. If the voltage at two ends of the direct current breaker is kept at about 400kV of rated voltage, the direct current breaker is judged to be a permanent fault and is not reclosed any more.
For a low-end VSC converter, the invention adopts a direct current breaker as an effective way for fault isolation, and the conventional hybrid direct current breaker mainly comprises a residual current cut-off switch RCB (residual current breaker), a quick isolating switch CB (circuit breaker), an auxiliary breaker LCS (load current switch) and a main breaker CCP (current communication path).
Wherein main circuit breaker and auxiliary circuit breaker contain modularization IGBT and arrester (metal oxide varistor, MOV), and during normal operating, load current only flows through auxiliary circuit breaker, because its on resistance is very little, consequently can effectively reduce the on-state loss. After the fault occurs, the auxiliary circuit breaker is quickly turned off, the switch-off quick isolating switch is quickly opened, the main circuit breaker is turned on, the main circuit breaker is turned off after the current conversion is completed, and finally, a small residual current is cut off by the residual current cut-off switch.
Above-mentioned circuit breaker can only break the fault current on a direct current circuit, carries out fault isolation for realizing many VSC tributaries in the mixed cascade multi-terminal direct current transmission system, then need dispose many direct current circuit breakers on many VSC tributaries that insert, and this can show to increase certainly and mix multi-terminal direct current transmission engineering cost.
With the development of the multi-terminal hybrid direct-current transmission technology, for a hybrid cascade multi-terminal direct-current transmission system, the construction cost and the operation loss of a direct-current circuit breaker are reduced, and the improvement of the technical economy is a key problem which needs to be solved urgently.
As shown in fig. 4, the topology includes m auxiliary breakers, 1 main breaker (CCP), and 1 MOV. The converter comprises m current-passing branches, a plurality of diodes D (D _1, D _2 and D _ m), a plurality of auxiliary circuit breakers and a plurality of current-passing branches, wherein the m current-passing branches are respectively connected with the m converter stations, each current-passing branch is divided into an upper bridge arm and a lower bridge arm, the upper bridge arm is formed by connecting fast disconnecting switches CB (CB _1, CB _2 and CB _ m) and auxiliary circuit breakers (load communication switch, LCS) (LCS _1, LCS _2 and LCS _ m) in series, the auxiliary circuit breakers are formed by single IGBT sub-modules, and the lower bridge arm is formed by connecting residual current cut-off switches K (K _1, K _2 and K _ m) and; the main breaker is formed by connecting n IGBT sub-modules in series; the energy consuming branch is made up of MOVs.
As shown in fig. 5, when a fault occurs in the dc line L2, the dc circuit breakers on both sides of the line are tripped immediately after the dc line protection action, and since the ac circuit breakers do not need to be tripped, the converter station does not need to be locked, the VSC converter station disconnected from the dc system can be quickly switched to the statcom operation mode, dynamic reactive support is provided for the ac system, the dc loads carried in the remaining dc network run without power outage, and the power supply reliability of the dc system is improved. And (4) after the direct current breaker is tripped, the direct current breaker is reclosed after the set arc quenching time, and if the reclosing is unsuccessful or the protection is judged to be a permanent fault, the direct current breaker is tripped again and is not reclosed any more [12 ]. The control sequence of the combined dc breaker when the dc line L2 fails is shown in fig. 6 and 7.
When the combined direct current circuit breaker normally operates, CB _1, CB _2 and CB _3 are in a closed state; k _1, K _2 and K _3 are in a closed state; LCS _1, LCS _2 and LCS _3 are in a conducting state; and when each submodule in the CCP is in an off state, current cannot flow between lower bridge arms of each current-flowing branch, and load current flows into each VSC branch from the LCC through each auxiliary breaker.
And (4) when a fault occurs at the time t1, and after the fault is detected, the direct-current protection sends a command of tripping the VSC1 fault line to the circuit breaker. At the time of t2, the direct-current circuit breaker controller firstly sends a switching-off command to CB _2 corresponding to a fault line and K _1 and K _ m corresponding to a non-fault line, and simultaneously sends a switching-on command to a current conversion branch CCP and a switching-off command to a load transfer branch LCS _ 2; under the action of turn-off overvoltage at two ends of a load transfer branch LCS _2, fault current is transferred from an upper bridge arm of a fault line to a branch in which a current conversion branch and a lower bridge arm of the fault line are connected in series, and current is transferred to CB _2 of the fault line and K _1 and K _ m of a non-fault line at time t3 to realize arc-free brake separation. At time t4, a simultaneous shutdown command is issued to the main breaker and K _2, and current is diverted from the CCP to the MOV. At time t5, K _2 is gated off to cut off the residual current, and t 5-t 6 are the line deionization time. the main circuit breaker is superposed at the time of t6, if the main circuit breaker is in temporary fault, the main circuit breaker is superposed successfully, the MOV is bypassed, the current flowing through the main circuit breaker is gradually increased, after the current is increased to the rated current of the system, the LCS is opened at the time of t7, the CCP is turned off, and the current is transferred from the CCP to the LCS; if a permanent fault is present, the current through the CCP rapidly increases to the protection threshold, and the CCP is turned off at time t 7.
The invention is further illustrated by the following examples:
a hybrid cascade multi-terminal direct-current transmission typical model containing a combined direct-current breaker is shown in a model topological structure in figure 4. Sending the end and adopting 800kV LCC converter valve, transmission capacity is 8GW, receiving the end high-end and adopting LCC converter valve interelectrode voltage to 400kV, receiving the end low side and adopting three VSC converter valve that connect in parallel, interelectrode voltage is 400kV, and high-end converter valve and low side converter valve accept 4GW power respectively. The load transfer branch is represented by a single sub-module, the parallel resistance R of the sub-module is 1 omega, C is 10uF, the MOV action voltage is set to be 2kV, the overvoltage capacity of the current commercial IGBT is 4.5kV, and the residual voltage after the MOV action is 3.5kV, which is smaller than the withstand voltage of the IGBT, so that the effect of protecting the IGBT is achieved. The main circuit breaker CCP needs a plurality of modules to be connected in series, the series number is 400kV/2kV is 200, the MOV action voltage is set to be 400kV, the residual voltage is 700kV after the MOV action, and the residual voltage is smaller than the endurance capacity of the main circuit breaker, so that the main circuit breaker is protected.
As shown in fig. 8, after the mechanical switch is closed, since the main breaker is not turned on, the current flowing through the mechanical switch is very small regardless of whether a transient fault or a permanent fault occurs in the line, and thus, the system and the equipment are not damaged.
As shown in fig. 9, when the mechanical switch is switched on after the transient fault is over, because the system dc voltage is mainly applied to the fault point, the two ends of the main breaker bear a small amount of voltage, which is consistent with the theoretical analysis, and reclosing can be performed at a proper time according to the attenuation speed of the dc voltage.
As shown in fig. 10, when a permanent fault occurs, after the mechanical switch is closed, since the fault point basically does not bear the dc voltage, the system dc voltage is mainly applied to both ends of the main breaker, and the voltage across the main breaker is maintained at the system voltage level and remains unchanged, which is consistent with the theoretical analysis, and at this time, reclosing is not performed.
The present invention further provides a reclosing system 200 of a dc circuit breaker based on voltages at two ends of the circuit breaker, as shown in fig. 11, including:
the first control module 201 is used for detecting faults of the direct current transmission system, and controlling the mechanical switch to be switched off after the direct current breaker of the direct current transmission system is turned off and residual current of the direct current breaker disappears when the direct current breaker of the direct current transmission system is determined to have faults;
the second control module 202 is used for determining whether the fault point of the fault is dissociated after 200ms after the mechanical switch is switched off, and switching on the mechanical switch after the fault point of the transient fault is dissociated;
and the third control module 203 is used for measuring the voltages at the two ends of the direct current circuit breaker in real time, determining that the fault is a transient fault if the voltages at the two ends of the direct current circuit breaker are continuously attenuated and are lower than the direct current voltage of the direct current transmission system, and reclosing the direct current circuit breaker of the direct current transmission system.
The third control module 203 is further configured to:
and if the voltage at the two ends of the direct current breaker is kept within 390-410kV, determining the permanent fault of the fault, and not reclosing the direct current breaker of the direct current transmission system.
The third control module 203 is further configured to: and after the direct-current circuit breaker of the direct-current transmission system is reclosed, determining whether the pole power of the direct-current circuit breaker is recovered to the power level before the fault, and if the pole power of the direct-current circuit breaker is not recovered to the power level before the fault, performing fault detection on the direct-current transmission system again.
According to the invention, the reclosing time of the direct current breaker is adaptively adjusted according to the voltage at the two ends of the main breaker after the mechanical switch is closed, so that the accuracy and the reliability of reclosing are improved.
As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting the same, and although the present invention is described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: modifications and equivalents may be made to the embodiments of the invention without departing from the spirit and scope of the invention, which is to be covered by the claims.
Claims (10)
1. A reclosing method of a direct current circuit breaker based on voltages at two ends of the circuit breaker, wherein the method comprises the following steps:
carrying out fault detection on the direct current transmission system, and controlling a mechanical switch to be switched off after the direct current breaker of the direct current transmission system is determined to be switched off and the residual current of the direct current breaker disappears when the direct current breaker of the direct current transmission system is determined to be in fault;
after the preset time after the mechanical switch is switched off is determined, whether the fault point of the fault is dissociated is judged, and when the fault point of the transient fault is dissociated, the mechanical switch is switched on;
and measuring the voltages at the two ends of the direct current breaker in real time, if the voltages at the two ends of the direct current breaker are attenuated continuously and are lower than the direct current voltage of the direct current transmission system, determining that the fault is an instantaneous fault, and reclosing the direct current breaker of the direct current transmission system.
2. The method of claim 1, further comprising:
and if the voltages at the two ends of the direct current breaker are kept within the preset threshold value, determining the permanent fault of the fault, and not reclosing the direct current breaker of the direct current transmission system.
3. The method of claim 1, the preset time being 200 ms.
4. The method as claimed in claim 2, wherein the predetermined threshold is 390-410 kV.
5. The method of claim 1, further comprising: and after the direct-current circuit breaker of the direct-current transmission system is reclosed, determining whether the pole power of the direct-current circuit breaker is recovered to the power level before the fault, and if the pole power of the direct-current circuit breaker is not recovered to the power level before the fault, performing fault detection on the direct-current transmission system again.
6. A dc circuit breaker reclosing system based on the voltage across the circuit breaker, the system comprising:
the first control module is used for carrying out fault detection on the direct current transmission system, and controlling the mechanical switch to be switched off after the direct current breaker of the direct current transmission system is determined to be switched off and the residual current of the direct current breaker disappears when the direct current breaker of the direct current transmission system is determined to be in fault;
the second control module is used for determining whether the fault point of the fault is dissociated after the preset time after the mechanical switch is switched off, and switching on the mechanical switch after the dissociation of the fault point of the transient fault is determined;
and the third control module is used for measuring the voltages at the two ends of the direct current circuit breaker in real time, determining that the fault is an instantaneous fault if the voltages at the two ends of the direct current circuit breaker are continuously attenuated and are lower than the direct current voltage of the direct current transmission system, and reclosing the direct current circuit breaker of the direct current transmission system.
7. The system of claim 6, the third control module further to:
and if the voltages at the two ends of the direct current breaker are kept within the preset threshold value, determining the permanent fault of the fault, and not reclosing the direct current breaker of the direct current transmission system.
8. The system of claim 6, the preset time being 200 ms.
9. The system as claimed in claim 7, wherein the predetermined threshold is 390-410 kV.
10. The system of claim 6, the third control module further to: and after the direct-current circuit breaker of the direct-current transmission system is reclosed, determining whether the pole power of the direct-current circuit breaker is recovered to the power level before the fault, and if the pole power of the direct-current circuit breaker is not recovered to the power level before the fault, performing fault detection on the direct-current transmission system again.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN112130063A (en) * | 2020-08-28 | 2020-12-25 | 许继集团有限公司 | Detection and protection method for mechanical switch tripping of hybrid high-voltage direct-current circuit breaker |
| CN112653080A (en) * | 2020-11-19 | 2021-04-13 | 郑州大学 | Self-adaptive reclosing method and controller for mechanical direct-current circuit breaker |
| CN114204515A (en) * | 2021-12-14 | 2022-03-18 | 阳光电源股份有限公司 | Control method of electromagnetic switch and electrical system |
| CN116581722A (en) * | 2023-06-20 | 2023-08-11 | 三峡电能有限公司 | Integrated device for power flow control and direct current breaking control and control method |
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| CN110416980A (en) * | 2019-06-18 | 2019-11-05 | 中国电力科学研究院有限公司 | A kind of adaptive reclosing method of combined DC breaker |
| US20200014190A1 (en) * | 2017-11-30 | 2020-01-09 | Tianjin University | Micro-loss combined mechanical dc circuit breaker and its control method |
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| US20200014190A1 (en) * | 2017-11-30 | 2020-01-09 | Tianjin University | Micro-loss combined mechanical dc circuit breaker and its control method |
| CN110137923A (en) * | 2019-05-30 | 2019-08-16 | 华中科技大学 | A kind of adaptive reclosing method of flexible HVDC transmission system containing dc circuit breaker |
| CN110416980A (en) * | 2019-06-18 | 2019-11-05 | 中国电力科学研究院有限公司 | A kind of adaptive reclosing method of combined DC breaker |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN112130063A (en) * | 2020-08-28 | 2020-12-25 | 许继集团有限公司 | Detection and protection method for mechanical switch tripping of hybrid high-voltage direct-current circuit breaker |
| CN112130063B (en) * | 2020-08-28 | 2024-04-12 | 许继集团有限公司 | Detection and protection method for mechanical switch theft jump of hybrid high-voltage direct-current breaker |
| CN112653080A (en) * | 2020-11-19 | 2021-04-13 | 郑州大学 | Self-adaptive reclosing method and controller for mechanical direct-current circuit breaker |
| CN112653080B (en) * | 2020-11-19 | 2022-12-02 | 郑州大学 | Self-adaptive reclosing method and controller for mechanical direct-current circuit breaker |
| CN114204515A (en) * | 2021-12-14 | 2022-03-18 | 阳光电源股份有限公司 | Control method of electromagnetic switch and electrical system |
| CN116581722A (en) * | 2023-06-20 | 2023-08-11 | 三峡电能有限公司 | Integrated device for power flow control and direct current breaking control and control method |
| CN116581722B (en) * | 2023-06-20 | 2024-01-23 | 三峡电能有限公司 | Integrated device for power flow control and direct current breaking control and control method |
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