CN113629749B - Single-station exit method and device of multi-terminal direct current transmission system - Google Patents
Single-station exit method and device of multi-terminal direct current transmission system Download PDFInfo
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- CN113629749B CN113629749B CN202010386989.XA CN202010386989A CN113629749B CN 113629749 B CN113629749 B CN 113629749B CN 202010386989 A CN202010386989 A CN 202010386989A CN 113629749 B CN113629749 B CN 113629749B
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- 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
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/36—Arrangements for transfer of electric power between ac networks via a high-tension dc link
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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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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/60—Arrangements for transfer of electric power between AC networks or generators via a high voltage DC link [HVCD]
Abstract
The application discloses a single-station exit method of a multi-terminal direct current transmission system.A converter station control protection system locks a converter to be exited and a tripping alternating current side switch after receiving an exit instruction; locking the direct current power control station; locking the direct-current voltage control station; detecting the current flowing through the breaker at the station to be exited, and issuing a breaker opening command when the current is lower than a preset breaking threshold value and continuously exceeds a first preset time setting value and all the converter stations are locked; after the breaker is tripped, the station to be exited executes direct current side pole isolation; re-unlocking the direct-current voltage control station and controlling the direct-current voltage to a normal value; the DC power control station is unlocked again and the DC power is controlled to a normal value. The technical scheme provided by the application ensures that the circuit breaker is separated when the current flowing through the circuit breaker is basically zero, and the multi-terminal direct current transmission project can select a high-voltage circuit breaker with low cost and simple structure after the application is adopted, so that the construction cost is effectively reduced, and the reliability and the flexibility of the system operation are improved.
Description
Technical Field
The application relates to the field of direct current transmission, in particular to a single-station exit method and device of a multi-terminal direct current transmission system.
Background
In the multi-terminal direct current transmission application, if a single station fails in an area or needs to be overhauled, the optimal mode is that the station is withdrawn online, and other stations continue to operate.
One way is to add a direct current breaker with strong breaking current capability between the converter station and the direct current line, and to isolate the fault station rapidly through the direct current breaker. However, the dc circuit breaker has high cost, large occupation, complex construction and reduced reliability. Under the prior art, along with the rise of voltage class, the cost and difficulty of the direct current breaker are increased in an exponential manner, and the direct current breaker can not be applied in the ultra-high voltage occasion.
The other way is to adopt the high-voltage circuit breaker which is changed by the conventional alternating current circuit breaker, the structure is simple, the cost is low, and the high-voltage circuit breaker is almost applicable to any voltage class. But the breaking direct current capacity is very limited, even tens of amperes are only needed in the ultra-high voltage occasion. Therefore, the high-voltage circuit breaker cannot directly go to a rapid isolation fault station, and a protection system needs to be controlled to control the current to be below breaking current so as to be reliably isolated.
In view of economy and reliability, the realization of online withdrawal of a converter station by using a high-voltage circuit breaker in an extra-high voltage application is the only choice in the prior art. The power generally transmitted by the extra-high voltage engineering is very high, and the power fluctuation caused in the station withdrawal process has a great influence on the stable operation of the system, so that the station withdrawal strategy needs to be matched with the stability control, and generally, the shorter the time of the power from one stable state to the other stable state is, the better the time is, namely the shorter the station withdrawal process is. For some distribution network projects or projects with limited cost, the high voltage circuit breaker scheme is also an effective measure for reducing the cost. Therefore, there is a need to study a single-station exit strategy for multi-terminal dc power transmission based on high voltage circuit breakers, ensuring that the converter station can be reliably isolated and the station exit process is short.
Disclosure of Invention
The application aims to provide a single-station exit method and device of a multi-terminal direct-current transmission system, which solve the problem of reliable and rapid breaking of a high-voltage circuit breaker and are suitable for multi-terminal direct-current transmission engineering.
In order to achieve the above object, the solution of the present application is:
in a first aspect, the present application provides a single-station exit method of a multi-terminal dc power transmission system, where the multi-terminal dc power transmission system at least includes three converter stations, one of the converter stations is a dc voltage control station, the other converter stations are dc power control stations, and each converter station is connected by a dc line; at least one breaker is configured between the to-be-withdrawn convertor station and the direct current line; the single station exit method comprises the following steps:
after receiving the station withdrawing instruction, the converter station control protection system locks the converter to be withdrawn and trips the AC side switch;
locking the direct current power control station;
locking the direct-current voltage control station;
detecting the current flowing through the breaker at the station to be exited, and issuing a breaker opening command when the current is lower than a preset breaking threshold value and continuously exceeds a first preset time setting value and all the converter stations are locked;
after the breaker is tripped, the station to be exited executes direct current side pole isolation, re-unlocks the direct current voltage control station and controls the direct current voltage to a normal value, re-unlocks the direct current power control station and controls the direct current power to the normal value.
Preferably, the blocking direct current power control station comprises: and after the direct current power is reduced to zero according to a certain slope by the direct current power control station, locking the direct current power control station.
Preferably, the blocking direct current power control station comprises: detecting the current direct current power or current, and directly locking the direct current power control station when the current power or current locking threshold is lower than the set power or current locking threshold, otherwise, controlling the direct current power to the locking threshold and then locking the direct current power control station.
Preferably, if the station to be exited is a dc voltage control station, after the inverter of the station to be exited is locked and the ac side switch is tripped, one of the original dc power control stations takes over the dc voltage control to become a new dc voltage control station.
Preferably, if the converter valve of the non-exiting DC power control station is a thyristor converter valve, only phase shifting may be performed without blocking.
Preferably, the step of locking out the dc voltage control station comprises: and the direct-current voltage control station is used for locking the direct-current voltage control station after the direct-current voltage is controlled to zero by the direct-current voltage control station.
Preferably, the blocking dc voltage control station further comprises: and detecting the direct current direction and the amplitude of the direct current voltage control station, if the direct current direction is detected to be directed to the direct current line and the amplitude is higher than the overcurrent threshold, directly locking the direct current voltage control station, otherwise, firstly controlling the direct current voltage to be zero, and then locking the direct current voltage control station.
Preferably, the step of controlling the dc power to a normal value includes: and after the direct current power control station is unlocked, controlling the direct current power to be zero, and controlling the direct current power to be a normal value after the voltage of the direct current line is higher than a preset voltage threshold.
Preferably, the method further comprises: when detecting the current flowing through the breaker of the station to be withdrawn, if the current exceeds the preset breaking threshold for a duration exceeding the power interruption permission time, or the breaker does not successfully trip, the station withdrawal fails and the alternating current side switches of other stations are tripped.
Preferably, if the station to be logged out has communication failure with other stations, only the station to be logged out participates in operation, and the other stations do not participate in operation; after receiving the station withdrawal instruction, locking the converter to be withdrawn and tripping the AC side switch; after the exit station finishes locking and tripping the alternating current switch, directly detecting the current flowing through the breaker at the exit station, and when the current is lower than the breaking threshold value and continuously exceeds a second preset time set value, restarting the breaker, and after the breaker trips, executing direct current side pole isolation.
In a second aspect, the present application provides a single-station exit device of a multi-terminal dc power transmission system, where the multi-terminal dc power transmission system at least includes three converter stations, one of the converter stations is a dc voltage control station, the other converter stations are dc power control stations, and each converter station is connected by a dc line; at least one breaker is configured between the to-be-withdrawn convertor station and the direct current line; the single station exit device is characterized by comprising:
station blocking unit to be exited: the device is used for locking the converter to be withdrawn and tripping the AC side switch after receiving the withdrawal instruction;
normal station blocking unit: the system is used for locking the direct current power control station and the direct current voltage control station;
breaker breaking unit: the circuit breaker is used for detecting the current flowing through the circuit breaker at the station to be exited, and issuing a circuit breaker opening command when the current is lower than a preset breaking threshold value and continuously exceeds a first preset time setting value and all the converter stations are locked;
isolation and unlocking unit: and the direct current side pole isolation device is used for detecting the state of the circuit breaker, after confirming that the circuit breaker is tripped, executing direct current side pole isolation at the station to be tripped, re-unlocking the direct current voltage control station, controlling the direct current voltage to a normal value, re-unlocking the direct current power control station, and controlling the direct current power to the normal value.
Preferably, the locked direct current power control station in the normal station locking unit includes: and after the direct current power is reduced to zero according to a certain slope by the direct current power control station, locking the direct current power control station.
Preferably, the locked direct current power control station in the normal station locking unit includes: detecting the current direct current power or current, and directly locking the direct current power control station when the current power or current locking threshold is lower than the set power or current locking threshold, otherwise, controlling the direct current power to the locking threshold and then locking the direct current power control station.
Preferably, in the station to be withdrawn locking unit, if the station to be withdrawn is a dc voltage control station, after locking the converter of the station to be withdrawn and tripping the ac side switch, one original dc power control station is controlled to take over the dc voltage control to become a new dc voltage control station.
Preferably, if the converter valve of the non-exiting DC power control station is a thyristor converter valve, only phase shifting may be performed without blocking.
Preferably, the blocking direct current voltage control station in the normal station blocking unit includes: and the direct-current voltage control station is used for locking the direct-current voltage control station after the direct-current voltage is controlled to zero by the direct-current voltage control station.
Preferably, the normal station locking unit further includes, before locking the dc voltage control station: and detecting the direct current direction and the amplitude of the direct current voltage control station, if the direct current direction is detected to be directed to the direct current line and the amplitude is higher than the overcurrent threshold, directly locking the direct current voltage control station, otherwise, firstly controlling the direct current voltage to be zero, and then locking the direct current voltage control station.
Preferably, in the isolating and unlocking unit, controlling the dc power to a normal value includes: and after the direct current power control station is unlocked, controlling the direct current power to be zero, and controlling the direct current power to be a normal value after the voltage of the direct current line is higher than a preset voltage threshold.
After the scheme is adopted, the circuit breaker is arranged between the converter station and the direct current line, and the circuit breaker is in a non-voltage and non-current state in a mode of briefly reducing the voltage of the direct current line to zero and locking all the converter stations, so that the circuit breaker is ensured to be separated when the current flowing through the circuit breaker is basically zero; after the breaker is tripped, the breaker is not withdrawn from the stand to unlock again and the direct current power is controlled to a normal value, so that the system power pause time caused by the whole process is shorter, and the requirement of stable operation of the system can be met. When the fault point possibly causes the overcurrent of the non-exit station equipment, a direct current reverse current prejudgment criterion is adopted to accelerate the locking process, so that the protection action of the non-exit station is avoided. The multi-terminal direct current transmission project can select the high-voltage circuit breaker with low cost and simple structure, thereby effectively reducing the construction cost and improving the reliability and the flexibility of the system operation.
Drawings
FIG. 1 is a schematic diagram of the main wiring of a three terminal DC embodiment of the present application;
FIG. 2 is a single station exit method basic flow diagram of the present application;
FIG. 3 is a flow chart of a method for a DC voltage control station to exit;
FIG. 4 is a flow chart of a DC control station acceleration lock-out method of the present application;
fig. 5 is a flow chart of a multi-power station power recovery method of the present application;
FIG. 6 is a flow chart of a method of station exit under communication failure of the present application;
fig. 7 is a schematic diagram of a multi-terminal dc single station exit device according to the present application.
Detailed Description
The following describes specific embodiments of the present application in detail with reference to the drawings.
The single station exit method provided by the application is suitable for a multi-terminal direct current transmission system, and comprises multi-terminal conventional direct current, multi-terminal flexible direct current and multi-terminal mixed direct current. The multi-terminal direct current transmission system at least comprises three converter stations, wherein one converter station is a direct current voltage control station, the other converter stations are direct current power control stations, and each converter station is connected to a direct current line; at least one circuit breaker is arranged between the exit converter station and the direct current line. Fig. 1 shows a three-terminal dc embodiment, in which the dc sides of three converter stations are connected to a positive line 11 and a negative line 12, a circuit breaker 13 is not configured in the converter station 1, one converter station 2 is configured, two converter stations 3 are configured, and the converter station 2 and the converter station 3 are provided with the single-station exit method implementation conditions proposed in the present embodiment.
The application provides a single station exit method embodiment I of a multi-terminal direct current transmission system, referring to FIG. 2, the method comprises the following steps:
step 201, after receiving a station withdrawal instruction, the converter station control protection system locks the converter to be withdrawn and trips the alternating current side switch.
Specifically, if the station-exiting command is issued manually, an operator can be required to manually reduce the station power to the minimum first and issue or the control system automatically controls the power to the minimum and then locks after issuing; and if the station withdrawal command is issued for protection, directly locking the converter to be withdrawn.
Step 202, locking out the DC power control station.
Specifically, the direct current power is reduced to zero according to a certain slope by the direct current power control station, and then the direct current power control station is locked.
In a preferred embodiment, the present dc power or current is detected, and when the current or the current blocking threshold is lower than the set power or current blocking threshold, the dc power control station is directly blocked, otherwise, the dc power is controlled to the blocking threshold and then the dc power control station is blocked. In order to shorten this process, the slope is preferably as high as possible without affecting the control performance.
Step 203, locking the direct-current voltage control station.
Specifically, the direct-current voltage control station controls the direct-current voltage to be reduced to zero according to a certain slope and then locks the converter; in order to shorten this process, the slope is preferably as high as possible without affecting the control performance.
204, detecting the current flowing through the breaker at the station to be exited, and issuing a breaker opening command when the current is lower than a preset breaking threshold value and continuously exceeds a first preset time set value and all the converter stations are locked;
specifically, the breaking threshold is set according to the breaking current allowed by the breaker, the breaking current of the high-voltage breaker aiming at the object is low cost, the breaking current is small, and the threshold needs to fully consider the influence of measurement precision to leave a proper margin; to shorten this process, the first preset time is as small as possible, but is at least greater than or equal to half the frequency period of the ac system.
Step 205, detecting that the circuit breaker to be exited is located.
Specifically, for a converter station configured with only one circuit breaker, only the position division of the circuit breaker is detected; for a converter station provided with two circuit breakers, it is preferable to detect the equipartition of the two circuit breakers.
Step 206, the station to be exited performs dc side pole isolation.
Specifically, after the circuit breaker connected between the exit station and the direct current line is separated, the direct current side pole is further isolated, so that the circuit breaker is reliably disconnected from the direct current line. The pole isolation requires at least one isolation knife between the inverter and the positive dc line and at least one isolation knife between the inverter and the negative dc line.
Step 207, unlock the dc voltage control station again and voltage-control the dc voltage to the normal value.
Specifically, after the circuit breaker connected between the exit station and the direct current line is separated, the direct current voltage control station unlocks again and controls the direct current voltage to rise to a normal value according to a certain slope; in order to shorten this process, the slope is preferably as high as possible without affecting the control performance.
Step 208, the DC power control station is unlocked again and the DC power is controlled to a normal value.
Specifically, after the circuit breaker connected between the exit station and the direct current line is separated, the direct current power control station unlocks again and controls the direct current power to rise to a normal value according to a certain slope; in order to shorten this process, the slope is preferably as high as possible without affecting the control performance.
When the multi-terminal direct current transmission project operates, only one direct current voltage control station is generally arranged, and the operating direct current power control station can have a certain taking-over sequence for direct current voltage control. As shown in fig. 3, a further embodiment of a single-station exit method of a multi-terminal dc power transmission system adjusts the steps 201 to 203 of the first embodiment to the following steps on the basis of the first embodiment:
step 301, a to-be-withdrawn direct-current voltage control station receives a station withdrawing instruction, and locks the converter and the ac-skip side switch.
Specifically, if the station exit command is issued manually, an operator can be required to manually or automatically adjust the power command of the power control station by a program, and the power of the station to be exited is controlled to be minimum and then locked; and if the station withdrawal command is issued for protection, directly locking the converter to be withdrawn.
Step 302, the dc power control station takes over dc voltage control by one of the stations according to a predetermined sequence.
Specifically, the running dc power control station immediately takes over dc voltage control when the original dc voltage control station is locked according to a preset dc voltage control take-over sequence, and becomes a new dc voltage control station.
Step 303, the remaining dc power control station locks after controlling the dc power to zero.
Specifically, the remaining dc power control station drops the dc power to zero according to a certain slope, and then locks the dc power control station.
In a preferred embodiment, the dc power or current of the remaining dc power control station is detected, and when the dc power or current is below a set power or current blocking threshold, the dc power control station is directly blocked, otherwise, the dc power is controlled to the blocking threshold before the dc power control station is blocked. In order to shorten this process, the slope is preferably as high as possible without affecting the control performance.
Step 304, the new dc voltage control station locks after the dc voltage is controlled to zero.
Specifically, the new direct current voltage control station controls the direct current voltage to be reduced to zero according to a certain slope and then locks the converter; in order to shorten this process, the slope is preferably as high as possible without affecting the control performance.
In a preferred embodiment, based on the foregoing embodiment of the single-station exit method of the multi-terminal dc power transmission system, when the multi-terminal dc power transmission system is a hybrid dc, if the converter valve of the non-exit dc power control station is a thyristor converter valve, only the phase shift may be performed without blocking.
A further embodiment of a single station exit method of a multi-terminal DC power transmission system can accelerate the locking process of a DC voltage control station for the fault exit of a pole bus affecting the DC side. As shown in fig. 4, on the basis of the first embodiment, step 203 is adjusted to the following steps:
step 401, the direct-current voltage control station receives other station-exiting instructions.
Step 402, detecting a direct current direction and an amplitude of a direct current of the direct current voltage control station.
Step 403, determining whether the direct current direction points to the direct current line and the amplitude is higher than the preset current threshold, if yes, executing step 404, otherwise executing step 405.
Step 404, the inverter is directly locked.
Specifically, the preset current threshold needs to be smaller than the tolerance capability of the dc bus and ensure that the failure of the outbound does not cause any protection action of the normal dc voltage control station.
Step 405, the dc voltage is locked after being controlled to zero according to a certain slope.
In the foregoing single-station exit method of the multi-terminal dc power transmission system, after the fault station circuit breaker divides the position, the rest of the converter stations will recover the dc voltage or dc power, as shown in fig. 5, and in another embodiment of the single-station exit method of the multi-terminal dc power transmission system, based on the first embodiment, step 208 of the first embodiment is adjusted as follows:
step 501, the direct current power control station receives the circuit breaker split of the exit station.
Step 502, the inverter unlocks and controls zero power.
Specifically, for the converter adopting the full-control device, the zero power can be unlocked and controlled; for converters employing thyristors, the phase shift is maintained.
Step 503, detecting that the voltage of the dc line is higher than a preset voltage threshold, and controlling the dc power to a normal value according to a certain slope.
Specifically, the preset voltage threshold may be set according to the type of the converter and the power command of the converter station, respectively: if the rectifying station is set lower and the inverting station is set higher, the direct-current voltage establishment process can be accelerated; the converter station setting using thyristor converter valves is low, accelerating the current build-up process.
In a preferred embodiment, based on the foregoing embodiment of a single-station exit method of a multi-terminal dc power transmission system, if the current of the breaker at the exit station does not meet the condition exceeding the power interruption allowable time or the breaker does not successfully trip, the exit station fails and notifies other stations to trip the ac side switch.
In yet another embodiment of a single station exit method of a multi-terminal dc power transmission system, if a communication failure occurs between the exit stations, the other stations will not receive the exit signal and cannot be locked and restarted. For faults affecting the direct current side, other stations perform corresponding operations according to the protection action conditions of the other stations; for faults that do not affect the dc side, the faulty station may be isolated. As shown in fig. 6, a station-exiting method under a communication failure includes the following steps:
and 601, under the condition of communication faults with other stations, receiving a station returning instruction, and locking a station to be returned and a switch at the alternating current side.
Step 602, detecting that the current of the circuit breaker to be withdrawn is lower than a preset breaking threshold value for exceeding a second preset time setting value, and issuing a circuit breaker breaking command.
Specifically, since other stations are still running, the second preset time set value is far greater than the first preset time set value, and the breaking failure caused by the fact that the current fluctuation flowing through the breaker exceeds the breaking threshold value is avoided.
And 603, detecting the position division of the circuit breaker to be withdrawn, and issuing direct current side pole isolation.
After the scheme is adopted, the circuit breaker is arranged between the converter station and the direct current line, and the circuit breaker is in a non-voltage and non-current state in a mode of briefly reducing the voltage of the direct current line to zero and locking all the converter stations, so that the circuit breaker is ensured to be separated when the current flowing through the circuit breaker is basically zero; after the breaker is tripped, the breaker is not withdrawn from the stand to unlock again and the direct current power is controlled to a normal value, so that the system power pause time caused by the whole process is shorter, and the requirement of stable operation of the system can be met. When the fault point possibly causes the overcurrent of the non-exit station equipment, a direct current reverse current prejudgment criterion is adopted to accelerate the locking process, so that the protection action of the non-exit station is avoided. The multi-terminal direct current transmission project can select the high-voltage circuit breaker with low cost and simple structure, thereby effectively reducing the construction cost and improving the reliability and the flexibility of the system operation.
Fig. 7 shows an embodiment of a single-station exit device of a multi-terminal dc power transmission system according to the present application, where the multi-terminal dc power transmission system includes at least three converter stations, one of the converter stations is a dc voltage control station, and the other converter stations are dc power control stations, and each converter station is connected by a dc line; at least one breaker is configured between the to-be-withdrawn convertor station and the direct current line; the single station exit device includes: the device comprises a station locking unit to be exited, a normal station locking unit, a breaker opening unit and a breaker opening unit. Wherein:
station blocking unit to be exited: and the switching device is used for locking the converter to be withdrawn and tripping the AC side switch after receiving the withdrawal command.
Normal station blocking unit: for blocking the dc power control station and for blocking the dc voltage control station.
Breaker breaking unit: and the circuit breaker is used for detecting the current flowing through the circuit breaker at the station to be exited, and issuing a circuit breaker opening command when the current is lower than a preset breaking threshold value and continuously exceeds a first preset time setting value and all the converter stations are locked.
Isolation and unlocking unit: and the direct current side pole isolation device is used for detecting the state of the circuit breaker, after confirming that the circuit breaker is tripped, executing direct current side pole isolation at the station to be tripped, re-unlocking the direct current voltage control station, controlling the direct current voltage to a normal value, re-unlocking the direct current power control station, and controlling the direct current power to the normal value.
In a preferred embodiment, on the basis of the above device embodiment, the locked dc power control station in the normal station locking unit includes: and after the direct current power is reduced to zero according to a certain slope by the direct current power control station, locking the direct current power control station.
In a preferred embodiment, on the basis of the above device embodiment, the locked dc power control station in the normal station locking unit includes: detecting the current direct current power or current, and directly locking the direct current power control station when the current power or current locking threshold is lower than the set power or current locking threshold, otherwise, controlling the direct current power to the locking threshold and then locking the direct current power control station.
In a preferred embodiment, in the device embodiment, if the station to be exited is a dc voltage control station, after the converter of the station to be exited is locked and the ac side switch is tripped, the blocking unit of the station to be exited controls one original dc power control station to take over the dc voltage control to become a new dc voltage control station.
In a preferred embodiment, based on the embodiment of the device, if the converter valve which does not exit the dc power control station is a thyristor converter valve, only phase shifting can be performed without blocking.
In a preferred embodiment, on the basis of the above device embodiment, the blocking dc voltage control station in the normal station blocking unit includes: and the direct-current voltage control station is used for locking the direct-current voltage control station after the direct-current voltage is controlled to zero by the direct-current voltage control station.
In a preferred embodiment, on the basis of the above device embodiment, the normal station locking unit further includes, before locking the dc voltage control station: and detecting the direct current direction and the amplitude of the direct current voltage control station, if the direct current direction is detected to be directed to the direct current line and the amplitude is higher than the overcurrent threshold, directly locking the direct current voltage control station, otherwise, firstly controlling the direct current voltage to be zero, and then locking the direct current voltage control station.
In a preferred embodiment, on the basis of the above device embodiment, the isolating and unlocking unit controls the dc power to a normal value includes: and after the direct current power control station is unlocked, controlling the direct current power to be zero, and controlling the direct current power to be a normal value after the voltage of the direct current line is higher than a preset voltage threshold.
Finally, it should be noted that: the technical solution of the present application is described in conjunction with the above embodiments only and is not limited thereto. Those of ordinary skill in the art will appreciate that: modifications and equivalents may be made to the particular embodiments of the application by those skilled in the art, and such modifications and variations are within the scope of the pending patent application.
Claims (18)
1. A single station exit method of a multi-terminal direct current transmission system at least comprises three converter stations, wherein one converter station is a direct current voltage control station, the other converter stations are direct current power control stations, and the converter stations are connected through direct current lines; at least one breaker is configured between the to-be-withdrawn convertor station and the direct current line; the single-station exit method is characterized by comprising the following steps:
after receiving the station withdrawing instruction, the converter station control protection system locks the converter to be withdrawn and trips the AC side switch;
locking the direct current power control station;
locking the direct-current voltage control station;
detecting the current flowing through the breaker at the station to be exited, and issuing a breaker opening command when the current is lower than a preset breaking threshold value and continuously exceeds a first preset time setting value and all the converter stations are locked;
after the breaker is tripped, the station to be exited executes direct current side pole isolation, re-unlocks the direct current voltage control station and controls the direct current voltage to a normal value, re-unlocks the direct current power control station and controls the direct current power to the normal value.
2. The single station exit method of a multi-terminal direct current transmission system of claim 1 wherein: the blocking DC power control station comprises: and after the direct current power is reduced to zero according to a certain slope by the direct current power control station, locking the direct current power control station.
3. The single station exit method of a multi-terminal direct current transmission system of claim 1 wherein: the blocking DC power control station comprises: detecting the current direct current power or current, and directly locking the direct current power control station when the current power or current locking threshold is lower than the set power or current locking threshold, otherwise, controlling the direct current power to the locking threshold and then locking the direct current power control station.
4. The single station exit method of a multi-terminal direct current transmission system of claim 1 wherein: if the station to be withdrawn is a direct-current voltage control station, after locking the converter of the station to be withdrawn and tripping the alternating-current side switch, one of the original direct-current power control stations takes over direct-current voltage control to become a new direct-current voltage control station.
5. The single station exit method of a multi-terminal direct current transmission system of claim 1 wherein: if the converter valve of the non-exit DC power control station is a thyristor converter valve, only phase shifting can be performed without blocking.
6. The single station exit method of a multi-terminal direct current transmission system of claim 1 wherein: the step of locking the direct current voltage control station comprises the following steps: and the direct-current voltage control station is used for locking the direct-current voltage control station after the direct-current voltage is controlled to zero by the direct-current voltage control station.
7. The single station exit method of a multi-terminal direct current transmission system of claim 1 wherein: the blocking direct current voltage control station further comprises the following components: and detecting the direct current direction and the amplitude of the direct current voltage control station, if the direct current direction is detected to be directed to the direct current line and the amplitude is higher than the overcurrent threshold, directly locking the direct current voltage control station, otherwise, firstly controlling the direct current voltage to be zero, and then locking the direct current voltage control station.
8. The single station exit method of a multi-terminal direct current transmission system of claim 1 wherein: the step of controlling the direct current power to a normal value comprises the following steps: and after the direct current power control station is unlocked, controlling the direct current power to be zero, and controlling the direct current power to be a normal value after the voltage of the direct current line is higher than a preset voltage threshold.
9. The single station exit method of a multi-terminal direct current transmission system of claim 1 wherein: further comprises: when detecting the current flowing through the breaker of the station to be withdrawn, if the current exceeds the preset breaking threshold for a duration exceeding the power interruption permission time, or the breaker does not successfully trip, the station withdrawal fails and the alternating current side switches of other stations are tripped.
10. The single station exit method of a multi-terminal direct current transmission system of claim 1 wherein: if the communication between the station to be logged out and other stations fails, only the station to be logged out participates in the operation, and the other stations do not participate in the operation; after receiving the station withdrawal instruction, locking the converter to be withdrawn and tripping the AC side switch; after the exit station finishes locking and tripping the alternating current switch, directly detecting the current flowing through the breaker at the exit station, and when the current is lower than the breaking threshold value and continuously exceeds a second preset time set value, restarting the breaker, and after the breaker trips, executing direct current side pole isolation.
11. A single station exit device of a multi-terminal direct current transmission system at least comprises three converter stations, wherein one converter station is a direct current voltage control station, the other converter stations are direct current power control stations, and the converter stations are connected through direct current lines; at least one breaker is configured between the to-be-withdrawn convertor station and the direct current line; the single station exit device is characterized by comprising:
station blocking unit to be exited: the device is used for locking the converter to be withdrawn and tripping the AC side switch after receiving the withdrawal instruction;
normal station blocking unit: the system is used for locking the direct current power control station and the direct current voltage control station;
breaker breaking unit: the circuit breaker is used for detecting the current flowing through the circuit breaker at the station to be exited, and issuing a circuit breaker opening command when the current is lower than a preset breaking threshold value and continuously exceeds a first preset time setting value and all the converter stations are locked;
isolation and unlocking unit: and the direct current side pole isolation device is used for detecting the state of the circuit breaker, after confirming that the circuit breaker is tripped, executing direct current side pole isolation at the station to be tripped, re-unlocking the direct current voltage control station, controlling the direct current voltage to a normal value, re-unlocking the direct current power control station, and controlling the direct current power to the normal value.
12. The single station exit device of a multi-terminal direct current transmission system of claim 11 wherein: the locked direct current power control station in the normal station locking unit comprises: and after the direct current power is reduced to zero according to a certain slope by the direct current power control station, locking the direct current power control station.
13. The single station exit device of a multi-terminal direct current transmission system of claim 11 wherein: the locked direct current power control station in the normal station locking unit comprises: detecting the current direct current power or current, and directly locking the direct current power control station when the current power or current locking threshold is lower than the set power or current locking threshold, otherwise, controlling the direct current power to the locking threshold and then locking the direct current power control station.
14. The single station exit device of a multi-terminal direct current transmission system of claim 11 wherein: in the station to be withdrawn locking unit, if the station to be withdrawn is a direct-current voltage control station, after locking the converter of the station to be withdrawn and tripping the alternating-current side switch, controlling an original direct-current power control station to take over direct-current voltage control to become a new direct-current voltage control station.
15. The single station exit device of a multi-terminal direct current transmission system of claim 11 wherein: if the converter valve of the non-exit DC power control station is a thyristor converter valve, only phase shifting can be performed without blocking.
16. The single station exit device of a multi-terminal direct current transmission system of claim 11 wherein: the blocking direct current voltage control station in the normal station blocking unit includes: and the direct-current voltage control station is used for locking the direct-current voltage control station after the direct-current voltage is controlled to zero by the direct-current voltage control station.
17. The single station exit device of a multi-terminal direct current transmission system of claim 11 wherein: the normal station locking unit further comprises, before locking the direct-current voltage control station: and detecting the direct current direction and the amplitude of the direct current voltage control station, if the direct current direction is detected to be directed to the direct current line and the amplitude is higher than the overcurrent threshold, directly locking the direct current voltage control station, otherwise, firstly controlling the direct current voltage to be zero, and then locking the direct current voltage control station.
18. The single station exit device of a multi-terminal direct current transmission system of claim 11 wherein: in the isolation and unlocking unit, controlling the direct current power to a normal value includes: and after the direct current power control station is unlocked, controlling the direct current power to be zero, and controlling the direct current power to be a normal value after the voltage of the direct current line is higher than a preset voltage threshold.
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2015090100A1 (en) * | 2013-12-16 | 2015-06-25 | 国家电网公司 | On-line deblocking and blocking control method for extra-high voltage direct current transmission project converter |
| WO2016056274A1 (en) * | 2014-10-09 | 2016-04-14 | 三菱電機株式会社 | Dc circuit breaker |
| CN108879625A (en) * | 2018-07-19 | 2018-11-23 | 南京南瑞继保电气有限公司 | A kind of parallel connection multiterminal extra-high voltage direct-current transmission valve unit protection action processing method |
| CN110739715A (en) * | 2019-11-15 | 2020-01-31 | 中国南方电网有限责任公司超高压输电公司柳州局 | Method and device for online switching on and off of DC network of flexible direct-current station of multi-terminal hybrid DC power transmission system |
-
2020
- 2020-05-09 CN CN202010386989.XA patent/CN113629749B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2015090100A1 (en) * | 2013-12-16 | 2015-06-25 | 国家电网公司 | On-line deblocking and blocking control method for extra-high voltage direct current transmission project converter |
| WO2016056274A1 (en) * | 2014-10-09 | 2016-04-14 | 三菱電機株式会社 | Dc circuit breaker |
| CN108879625A (en) * | 2018-07-19 | 2018-11-23 | 南京南瑞继保电气有限公司 | A kind of parallel connection multiterminal extra-high voltage direct-current transmission valve unit protection action processing method |
| CN110739715A (en) * | 2019-11-15 | 2020-01-31 | 中国南方电网有限责任公司超高压输电公司柳州局 | Method and device for online switching on and off of DC network of flexible direct-current station of multi-terminal hybrid DC power transmission system |
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