CN112202150A - Method, medium and system for isolating faults of single converter of extra-high voltage converter station - Google Patents

Method, medium and system for isolating faults of single converter of extra-high voltage converter station Download PDF

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Publication number
CN112202150A
CN112202150A CN202010768913.3A CN202010768913A CN112202150A CN 112202150 A CN112202150 A CN 112202150A CN 202010768913 A CN202010768913 A CN 202010768913A CN 112202150 A CN112202150 A CN 112202150A
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China
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converter
breaker
station
fault
region
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CN112202150B (en
Inventor
史磊
宋海龙
刘志远
郝治国
于晓军
柴斌
刘若鹏
韦鹏
吴鹏
毛春翔
于小艳
徐辉
雷战斐
刘舒杨
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State Grid Corp of China SGCC
State Grid Ningxia Electric Power Co Ltd
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State Grid Corp of China SGCC
State Grid Ningxia Electric Power Co Ltd
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    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02HEMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H7/00Emergency 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
    • H02H7/26Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured
    • H02H7/268Sectionalised 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
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02JCIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00Circuit arrangements for ac mains or ac distribution networks
    • H02J3/36Arrangements for transfer of electric power between ac networks via a high-tension dc link
    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/60Arrangements for transfer of electric power between AC networks or generators via a high voltage DC link [HVCD]

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Inverter Devices (AREA)

Abstract

The invention discloses a method, medium and system for isolating faults of a single converter of an extra-high voltage converter station. The isolation method comprises the following steps: for each converter region, sequentially connecting a cathode breaker and a parallel breaker in series between the cathode disconnecting link and the bypass disconnecting link, and connecting an anode breaker in series between the bypass disconnecting link and the anode disconnecting link; when any converter region has a fault, controlling the fault converter region and a breaker of the converter region corresponding to the converter station on the opposite side of the converter station where the fault converter region is located to act according to a time sequence; wherein the sequence of actions includes: the bypass breaker is changed from opening to closing, the parallel breaker is changed from opening to closing, the cathode breaker is changed from closing to opening, the anode breaker is changed from closing to opening, and the bypass breaker is changed from closing to opening. The invention can realize the rapid isolation of the equipment fault point of the converter region.

Description

Method, medium and system for isolating faults of single converter of extra-high voltage converter station
Technical Field
The invention relates to the technical field of extra-high voltage converter station fault elimination, in particular to a method, medium and system for isolating a single converter fault of an extra-high voltage converter station.
Background
Under the operation mode of a bipolar four-converter or a bipolar three-converter or a unipolar double-converter, when a single converter fails, differential protection and polar differential protection of the converter can be caused, so that polar locking and polar isolation are caused, and because a disconnecting link of a cathode and an anode of the converter does not have the capacity of rapidly extinguishing arc and cutting off fault current, the time consumed by an isolation fault point exceeds 110s, the fault converter cannot be rapidly isolated within a short time required by a system stability limit, a power generator set matched with a sending end of a direct current project is cut off, and loads of a receiving end are cut off, so that power loss is caused, and the operation reliability of the direct current system is reduced.
Disclosure of Invention
The embodiment of the invention provides a fault isolation method, medium and system for a single converter of an extra-high voltage converter station, and aims to solve the problem that a fault converter cannot be isolated quickly in the prior art.
In a first aspect, a method for isolating a fault of a single converter in an extra-high voltage converter station is provided, where the extra-high voltage converter station includes two converter stations that are opposite to each other, one converter station is a rectifier station, the other converter station is an inverter station, each converter station includes two poles, each pole includes two converter regions, one converter region is a high-end converter region, the other converter region is a low-end converter region, each converter region is provided with a bypass breaker, a cathode disconnecting link, a bypass disconnecting link and an anode disconnecting link, and the bypass breaker, the cathode disconnecting link, the bypass disconnecting link and the anode disconnecting link are sequentially connected in series to form a loop, and the isolation method includes: for each converter region, sequentially connecting a cathode breaker and a parallel breaker in series between the cathode disconnecting link and the bypass disconnecting link, and connecting an anode breaker in series between the bypass disconnecting link and the anode disconnecting link; when any converter region has a fault, controlling the fault converter region and a breaker of the converter region corresponding to the converter station on the opposite side of the converter station where the fault converter region is located to act according to a time sequence; wherein the sequence of actions includes: the bypass breaker is changed from opening to closing, the parallel breaker is changed from opening to closing, the cathode breaker is changed from closing to opening, the anode breaker is changed from closing to opening, and the bypass breaker is changed from closing to opening.
In a second aspect, there is provided a computer readable storage medium having computer program instructions stored thereon; the computer program instructions, when executed by a processor, implement the method for isolating the single converter fault of the extra-high voltage converter station according to the embodiment of the first aspect.
In a third aspect, an isolation system for a single converter fault of an extra-high voltage converter station is provided, which includes: a computer readable storage medium as in the second aspect.
The embodiment of the invention adds three fast breakers, improves and optimizes the connection mode of a cathode disconnecting link, an anode disconnecting link and a bypass disconnecting link in the converter region of an extra-high voltage converter station and a control protection action strategy, is applied to the operation of all single-pole double converters, double-pole triple converters or double-pole four converters of the extra-high voltage direct current system, executes new control protection action logic after a single converter fails, can realize the fast isolation of equipment fault points in the single converter region, avoids the pole blocking and pole isolation operation of the fault converter and the cutting and receiving end load removal of a sending end matched power unit, realizes the continuous maintenance of the current power operation of a non-fault converter, and improves the operation reliability of the extra-high voltage direct current system.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the description of the embodiments of the present invention will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to these drawings without inventive labor.
FIG. 1 is a schematic circuit diagram of a pole 1 region of a prior art extra-high voltage converter station;
FIG. 2 is a schematic circuit diagram of a pole 1 region of an extra-high voltage converter station according to an embodiment of the invention;
fig. 3 is a flowchart of a method for isolating a single converter fault in an extra-high voltage converter station according to a preferred embodiment of the present invention;
fig. 4 is a flowchart of a method for isolating a single converter fault of an extra-high voltage converter station according to another preferred embodiment of the present invention.
Detailed Description
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, 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 extra-high voltage converter station comprises two converter stations which are opposite to each other. One converter station is a rectifier station, and the other converter station is an inverter station. Each converter station comprises two poles. Each pole includes two inverter regions. One converter region is a high-end converter region, and the other converter region is a low-end converter region. Each converter area is provided with a bypass breaker, a cathode disconnecting link, a bypass disconnecting link and an anode disconnecting link, and the bypass breaker, the cathode disconnecting link, the bypass disconnecting link and the anode disconnecting link are sequentially connected in series to form a loop.
Specifically, as shown in fig. 1, it is a schematic circuit diagram of a pole 1 region of an extra-high voltage converter station in the prior art. The pole 1 region of the extra-high voltage converter station comprises two converters, namely a high-end converter and a low-end converter.
In high side converter region 1, the high side converter is connected to a first thyristor assembly Thy 1. It should be understood that the first thyristor assembly Thy1 includes a plurality of thyristors connected in series, and that each group of thyristors connected in series may be connected in parallel, and that the specific connection configuration of the first thyristor assembly Thy1 may be set according to the actual situation. The cathode of the first thyristor assembly Thy1 is connected to one end of a first wall bushing TG 1. The other end of the first wall bushing TG1 is connected to one end of a first PLC reactor L1. The other end of the first PLC reactor L1 is connected to one end of a first cathode knife-switch Q13. A first current transformer T1 is connected in series between the first PLC reactor L1 and the first cathode disconnecting link Q13 and is used for collecting the high voltage of the pole 1 high-end converterSide current IDC1P. The anode of the first thyristor assembly Thy1 is connected to one end of a second wall bushing TG 2. The other end of the second wall bushing TG2 is connected to one end of a second PLC reactor L2. The other end of the second PLC reactor L2 is connected to one end of the first anode knife-switch Q11. A second current transformer T2 is connected in series between the second PLC reactor L2 and the first anode disconnecting link Q11 and is used for collecting the current I at the low-voltage side of the pole-1 high-end converterDC1N. A first bypass breaker Q1 is connected in parallel between one end of the first cathode knife switch Q13 and one end of the first anode knife switch Q11. A first bypass switch Q12 is connected in parallel across the other end of the first cathode switch Q13 and the other end of the first anode switch Q11. Therefore, the first bypass breaker Q1, the first cathode knife switch Q13, the first bypass knife switch Q12 and the first anode knife switch Q11 are connected in series in sequence to form a loop.
In the low side inverter region 2, the low side inverter is connected to a second thyristor assembly Thy 2. It should be understood that the second thyristor assembly Thy2 includes a plurality of thyristors connected in series, and that each group of thyristors connected in series may be connected in parallel, and the specific connection structure of the second thyristor assembly Thy2 may be set according to actual conditions. The cathode of the second thyristor Thy2 is connected to one end of a third wall bushing TG 3. The other end of the third wall bushing TG3 is connected to one end of a third PLC reactor L3. The other end of the third PLC reactor L3 is connected to one end of the second cathode knife-switch Q14. A third current transformer T3 is connected in series between the third PLC reactor L3 and the second cathode disconnecting link Q14 and is used for collecting the current I at the high-voltage side of the pole-1 low-end converterDC2P. The anode of the second thyristor assembly Thy2 is connected to one end of a fourth wall bushing TG 4. The other end of the fourth wall bushing TG4 is connected to one end of a fourth PLC reactor L4. The other end of the fourth PLC reactor L4 is connected to one end of a second anode knife-switch Q16. A fourth current transformer T4 is connected in series between the fourth PLC reactor L4 and the second anode disconnecting link Q16 and is used for collecting the current I at the low-voltage side of the pole-1 low-side converterDC2N. A second bypass breaker Q2 is connected in parallel at one end of a second cathode knife switch Q14 and at one end of a second anode knife switch Q16. A second bypass switch Q15 is connected in parallel across the other end of the second cathode switch Q14 and the other end of the second anode switch Q16. Thus, a second bypass breaker Q2, a second cathode knife switch Q14, a second bypass knifeThe gate Q15 and the second anode knife gate Q16 are connected in series in turn to form a loop.
The other end of the first anode knife-switch Q11 is connected to the other end of the second cathode knife-switch Q14. A direct current divider U1 of the connecting line of the pole 1 converter is connected between the other end of the first anode disconnecting link Q11 and the other end of the second cathode disconnecting link Q14 and is used for collecting the voltage U of the connecting line of the pole 1 converterDM
In addition, the extra-high voltage converter station pole 1 region further comprises: direct current filter Z, utmost point 1 utmost point neutral bus circuit breaker NBS, utmost point bus knife switch Q17, electric capacity C and arrester F.
One end of a dc filter Z is connected between the other end of the first cathode disconnecting link Q13 and one end of the pole bus disconnecting link Q17. The other end of the dc filter Z is connected to the other end of the second anode disconnecting link Q16. One end of the direct current filter Z is connected with a fifth current transformer T5 in series and used for collecting the head end current I of the direct current filter of the pole 1ZT1. The other end of the direct current filter Z is connected in series with a sixth current transformer T6 for collecting the tail end current I of the direct current filter of the pole 1ZT2
The other end of the first cathode knife-switch Q13 is connected to one end of a pole bus knife-switch Q17. A pole 1 bus direct current voltage divider U2 is connected between the other end of the first cathode disconnecting link Q13 and one end of the pole bus disconnecting link Q17 and is used for collecting a pole 1 bus voltage UDL. The other end of the pole bus disconnecting link Q17 is connected in series with a seventh current transformer T7 for collecting the pole 1 pole bus current IDL
The other end of the second anode knife switch Q16 is connected to one end of a pole 1 neutral bus breaker NBS. A pole 1 neutral bus direct-current voltage divider U3 is connected between the other end of the second anode disconnecting link Q16 and one end of the pole 1 neutral bus breaker NBS and used for collecting a pole 1 neutral bus voltage UDN(ii) a And an eighth current transformer T8 is connected in series and used for collecting the current I at the side of the neutral bus of the 1 pole of the collector close to the converter valveDNC. The other end of the pole 1 neutral bus breaker NBS is connected with a ninth current transformer T9 in series for collecting the current I of the pole 1 neutral bus close to the ground pole sideDNE
With one capacitor plate of capacitor C connected to pole-1 neutral bus breaker NBSOne end, the other plate of the capacitor C is grounded. The other capacitor plate of the capacitor C is connected with a tenth current transformer T10 in series for collecting the current I of the 1-pole neutral bus capacitorCN
One end of the lightning arrester F is connected to one end of the pole 1 neutral bus breaker NBS, and the other end of the lightning arrester F is grounded. The other end of the lightning arrester F is connected with an eleventh current transformer T11 in series and used for collecting the current I of the neutral bus lightning arrester with the 1 pole of the poleAN
The inverter structure of the other pole is the same as that of the pole 1, and is not described in detail herein.
Aiming at the extra-high voltage converter station, the embodiment of the invention provides a method for isolating a fault of a single converter of the extra-high voltage converter station. As shown in fig. 3, the isolation method includes the following steps:
step S1: for each converter region, a cathode breaker and a parallel breaker are connected in series between a cathode disconnecting link and a bypass disconnecting link in sequence, and an anode breaker is connected in series between the bypass disconnecting link and an anode disconnecting link.
The newly-added cathode circuit breaker, anode circuit breaker and parallel circuit breaker are all rapid circuit breakers which can be reliably switched off within 50ms and can be reliably switched on within 10 ms.
In a specific embodiment, taking the pole 1 region as an example, as shown in fig. 2, for the high-side inverter region 1, the other end of the first cathode disconnecting link Q13 is connected to one end of a first cathode breaker Q5, the other end of the first cathode breaker Q5 is connected to one end of a first parallel breaker Q4, and the other end of the first parallel breaker Q4 is connected to one end of a first bypass disconnecting link Q12. A first anode breaker Q3 is connected in series between the other end of the first anode knife switch Q11 and the other end of the first bypass knife switch Q12. Similarly, for the low side inverter region 2, the other end of the second cathode knife-switch Q14 is connected to one end of a second cathode breaker Q6, the other end of the second cathode breaker Q6 is connected to one end of a second parallel breaker Q7, and the other end of the second parallel breaker Q7 is connected to one end of a second bypass knife-switch Q15. A second anode breaker Q8 is connected in series between the other end of the second anode knife switch Q16 and the other end of the second bypass knife switch Q15.
Specifically, when the pole-1 high-side converter is in a connected state, the first anode disconnecting link Q11, the first bypass disconnecting link Q12 and the first cathode disconnecting link Q13 are all in a closed state, the first anode circuit breaker Q3 and the first cathode circuit breaker Q5 are in a closed state, and the first bypass breaker Q1 and the first parallel circuit breaker Q4 are in an open state. When the pole-1 low-side converter is in a connected state, the second cathode disconnecting link Q14, the second bypass disconnecting link Q15 and the second anode disconnecting link Q16 are all in a closed state, the second cathode breaker Q6 and the second anode breaker Q8 are in a closed state, and the second bypass breaker Q2 and the second parallel breaker Q7 are in an open state.
The structure of the inverter region of the other pole is the same as that of the pole 1, and the description thereof is omitted.
Step S2: and when any converter region has a fault, controlling the fault converter region and the breaker of the corresponding converter region of the opposite side converter station of the converter station where the fault converter region is located to act according to the time sequence.
The sequence of actions is specifically as follows: the bypass breaker is changed from opening to closing, the parallel breaker is changed from opening to closing, the cathode breaker is changed from closing to opening, the anode breaker is changed from closing to opening, and the bypass breaker is changed from closing to opening.
In addition, after the action time sequence is completed, the cathode disconnecting link of the fault converter region and the converter region corresponding to the converter station on the opposite side of the converter station where the fault converter region is located can be controlled to be changed from closing to opening, and the anode disconnecting link is changed from closing to opening, so that the condition that the circuit breaker is in malfunction to cause danger is further avoided.
It should be understood that after the operation in step S2 performs corresponding closing and opening, the actuated parallel circuit breaker, the cathode circuit breaker and the anode circuit breaker should be locked, i.e. the current closing and opening states of the two circuit breakers are maintained.
Therefore, the operation of the breaker in the faulty inverter region is controlled by the inverter differential protection operation, and the faulty inverter can be locked and isolated. Similarly, through the converter differential protection action, the breaker action of the corresponding converter zone of the opposite side converter station of the converter station where the fault converter zone is located is controlled, so that the corresponding converter of the opposite side converter station can be locked and isolated. For example, if the converter station is a rectifying station, the opposite converter station is an inverting station, and vice versa. For example, the corresponding converter region of the opposite side converter station to the high-end converter region of the pole 1 region of the rectifying station is the high-end converter region of the pole 1 region of the inverter station.
In a specific embodiment as shown in fig. 2, the fault point K1 of the pole 1 high side converter region 1 is a ground fault between the 800kV first bulkhead bushing TG1 of the pole 1 high side converter region 1 and the 800kV first PLC reactor L1 of the pole 1 high side converter region 1. When the extra-high voltage direct current system is in a bipolar four-converter earth return operation mode, a bipolar three-converter (a pole 1 double-converter pole 2 single-converter) earth return operation mode or a unipolar double-converter (a pole 1 double-converter) earth/metal return operation mode, a K1 fault occurs, the operation is performed according to the step, taking a pole 1 area as an example, the action processes of each breaker, each disconnecting link and each converter are as follows: first, the first bypass breaker Q1 is switched from open to closed, the pole-1 high-side converter is switched from on to off, the first parallel breaker Q4 is switched from open to closed, the first cathode breaker Q5 is switched from closed to open, the first anode breaker Q3 is switched from closed to open, and the first bypass breaker Q1 is switched from closed to open, then the pole-1 high-side converter is switched from connected to isolated. After the above-mentioned actions are performed, the first cathode knife switch Q can be performed13From closing to opening, the first anode knife switch Q11The action of switching on the circuit breaker is changed into switching off the circuit breaker, so that the condition that the circuit breaker is in malfunction to cause danger is further avoided. Similarly, the action process of each breaker, knife switch and converter of the corresponding converter region of the converter station on the opposite side of the converter station where the fault converter region is located is the same as the above process.
It should be understood that the operation of restoring a faulty converter from isolation to connected state is as follows: if the anode disconnecting link and the cathode disconnecting link in the fault current converter area are switched off, the anode disconnecting link and the cathode disconnecting link are switched on from switching off at first, then the locked circuit breaker is unlocked, the anode circuit breaker is switched on from switching off in sequence, the cathode circuit breaker is switched on from switching off, the parallel circuit breaker is switched on from switching on to switching off, and then the fault current converter is connected from isolation. Similarly, when the corresponding converter of the opposite converter station is restored from the isolation to the connected state, the corresponding operation is also performed.
For example, if it is desired to restore the pole 1 high side inverter from isolated to connected state, the first anode knife switch Q11And a first cathode knife switch Q13When the switch is opened, the first anode switch Q should be switched11The first cathode knife switch Q is changed from open switch to close switch13When the first positive breaker Q3 is sequentially switched from open to closed, the first negative breaker Q5 is switched from open to closed, and the first parallel breaker Q4 is switched from closed to open, the pole-1 high-side converter is switched from isolated to connected.
Therefore, the states of the individual circuit breaker and disconnecting link devices of the very-1 high/low side inverter of this embodiment in different states are defined as shown in tables 1 and 2.
Table 1 converter working state definition table after adding fast breaker in pole 1 high-end converter area
Circuit breaker/knife switch name Inverter connection state Inverter isolation state Fast circuit breaker overhaul state
First bypass breaker Q1 × × ×
First anode breaker Q3 × ×
First parallel circuit breaker Q4 × ×
First cathode breaker Q5 × ×
First anode knife switch Q11 × ×
First bypass switch Q12 ×
First cathode knife switch Q13 × ×
In table 1, "√" denotes closing and "×" denotes opening. As can be seen from table 1, when the pole-1 high-side inverter is in the connected state, the first anode disconnecting link Q11, the first bypass disconnecting link Q12 and the first cathode disconnecting link Q13 are all in the closed state, the first anode disconnecting link Q3 and the first cathode disconnecting link Q5 are in the closed state, and the first bypass disconnecting link Q1 and the first parallel disconnecting link Q4 are in the open state. When the pole-1 high-end converter is in an isolated state, the first bypass knife switch Q12 is in a closed state, the first anode knife switch Q11, the first cathode knife switch Q13, the first bypass breaker Q1, the first anode breaker Q3 and the first cathode breaker Q5 are in an open state, and the first parallel breaker Q4 is in a closed state. When the first anode breaker Q3, the first parallel breaker Q4 or the first cathode breaker Q5 has a fault and needs to be repaired, the corresponding first anode disconnecting link Q11, the first bypass disconnecting link Q12 or the first cathode disconnecting link Q13 is ensured to keep an open state.
Table 2 converter working state definition table after adding fast breaker to pole 1 low end converter region
Circuit breaker/knife switch name Inverter connection state Inverter isolation state Fast circuit breaker overhaul state
Second bypass breaker Q2 × × ×
Second cathode breaker Q6 × ×
Second parallel breaker Q7 × ×
Second anode breaker Q8 × ×
Second cathode knife switch Q14 × ×
Second bypass knife switch Q15 ×
Second anode knife switch Q16 × ×
In table 2, "√" denotes closing and "×" denotes opening. As can be seen from table 2, when the pole-1 low-side inverter is in the connected state, the second cathode knife switch Q14, the second bypass knife switch Q15, and the second anode knife switch Q16 are all in the closed state, the second cathode breaker Q6 and the second anode breaker Q8 are in the closed state, and the second bypass breaker Q2 and the second parallel breaker Q7 are in the open state. When the pole-1 low-side converter is in an isolated state, the second bypass knife switch Q15 is in a closed state, the second cathode knife switch Q14, the second anode knife switch Q16, the second bypass breaker Q2, the second cathode breaker Q6 and the second anode breaker Q8 are in an open state, and the second parallel breaker Q7 is in a closed state. When the second cathode breaker Q6, the second parallel breaker Q7 or the second anode breaker Q8 has faults and needs to be repaired, the corresponding second cathode disconnecting link Q14, the second bypass disconnecting link Q15 or the second anode disconnecting link Q16 is ensured to keep the open state.
Through the steps, the isolation of the fault current converter can be realized. After the faulty converter is isolated, the converter which is not faulty should continue to operate normally, so as shown in fig. 4, when any converter region is faulty, the method of the embodiment of the present invention further includes:
step S3: and shifting the phase of the non-faulty converter located in the same pole of the same converter station as the faulty converter region, and simultaneously shifting the phase of the corresponding converter of the converter station opposite to the converter station where the non-faulty converter is located.
Aiming at the specific embodiment, the phase of the pole 1 low-end converter is shifted through the differential protection action of the converter, and the pole 1 low-end converter is changed into an inversion mode; simultaneously, the corresponding pole 1 low-end converter of the opposite side converter station is shifted in phase, and the corresponding pole 1 low-end converter of the opposite side converter station is changed into an inversion mode.
For the phase shifting operation, the angle of the phase shift differs depending on the class of the converter station. Specifically, when the converter station is a rectifier station, the phase shifting comprises: the converter valve firing angle of the commutation station is shifted from 15 to 164. When the converter station is an inverter station, the phase shifting comprises: the converter valve firing angle of the inversion station is shifted from 140 to 164. In addition, the time length of the phase shift of the non-fault converter is generally 200ms, and can be set according to the actual situation.
It should be understood that although shown in a sequential relationship in fig. 4, in practice, step S3 is generally performed concurrently with step S2.
Step S4: after the preset time, the phase shifting of the non-fault converter and the corresponding converter of the pair of side converter stations is finished, and the normal operation is recovered.
Wherein the preset time is 200 ms. Specifically, when the converter station is a rectifying station, after normal operation is recovered, the triggering angle of the converter valve of the rectifying station is recovered from 164 degrees to 15 degrees. When the converter station is an inverter station, after normal operation is recovered, the trigger angle of a converter valve of the inverter station is recovered from 164 degrees to 140 degrees.
Through the steps, the non-fault current converter and the corresponding current converter of the opposite side current converting station can be enabled to recover normal operation, the pole where the fault point is located is prevented from being locked, the pole is isolated to operate, the power unit is matched with the sending end to be switched, the load of the receiving end is cut off, the non-fault current converter of the pole where the fault point is located is enabled to continuously keep current power operation, and the system is enabled to rapidly recover bipolar balanced operation.
In a specific embodiment, after 200ms, the normal operation of the pole 1 low-side converter is resumed, and the normal operation of the corresponding pole 1 low-side converter of the opposite side converter station is resumed, so that the pole 1 low-side converter continues to maintain the current power operation.
Embodiments of the present invention also provide a computer-readable storage medium having computer program instructions stored thereon; the computer program instructions are executed by a processor to realize the method for isolating the single converter fault of the extra-high voltage converter station according to the embodiment.
The embodiment of the invention also provides an isolation system for the single converter fault of the extra-high voltage converter station, which comprises the following steps: a computer readable storage medium as in the above embodiments.
To sum up, the embodiment of the invention adds three fast breakers, improves and optimizes the connection mode of the cathode disconnecting link, the anode disconnecting link and the bypass disconnecting link in the converter region of the ultra-high voltage converter station and the control protection action strategy, is applied to all the operation of the unipolar double-converter, the bipolar three-converter or the bipolar four-converter in the ultra-high voltage direct current system, executes new control protection action logic after the single-converter fails, can realize the fast isolation of the equipment fault point in the single-converter region, avoids the pole blocking and pole isolation operation of the fault converter, the transmission end matching power unit and the receiving end load removal, realizes the continuous maintenance of the current power operation of the non-fault converter, and improves the operation reliability of the ultra-high voltage direct current system.
The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and all the changes or substitutions should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims (9)

1. The utility model provides an isolation method of extra-high voltage converter station list converter trouble, extra-high voltage converter station includes each other two converter stations of offside, wherein, one converter station is the rectifier station, and another converter station is the inverter station, and each converter station includes two poles, and each pole includes two converter regions, and wherein, a converter region is high-end converter region, and another converter region is low-end converter region, and each converter region all is provided with bypass circuit breaker, negative pole switch, bypass switch and positive pole switch, and bypass circuit breaker, negative pole switch, bypass switch and positive pole switch connect gradually in series and form a return circuit, its characterized in that, the isolation method includes:
for each converter region, sequentially connecting a cathode breaker and a parallel breaker in series between the cathode disconnecting link and the bypass disconnecting link, and connecting an anode breaker in series between the bypass disconnecting link and the anode disconnecting link;
when any converter region has a fault, controlling the fault converter region and a breaker of the converter region corresponding to the converter station on the opposite side of the converter station where the fault converter region is located to act according to a time sequence;
wherein the sequence of actions includes: the bypass breaker is changed from opening to closing, the parallel breaker is changed from opening to closing, the cathode breaker is changed from closing to opening, the anode breaker is changed from closing to opening, and the bypass breaker is changed from closing to opening.
2. The method for isolating the single converter fault of the extra-high voltage converter station according to claim 1, wherein after the step of controlling the circuit breakers of the faulty converter region and the corresponding converter region of the converter station on the opposite side of the converter station where the faulty converter region is located to act according to the time sequence, the method further comprises:
and controlling the cathode disconnecting link of the fault converter region and the converter region corresponding to the converter station on the opposite side of the converter station where the fault converter region is located to change from closing to opening, and controlling the anode disconnecting link to change from closing to opening.
3. The method for isolating the single converter fault of the extra-high voltage converter station according to claim 1, further comprising the following steps:
when any converter region has a fault, shifting the phase of a non-fault converter which is positioned at the same pole of the same converter station as the fault converter region, and simultaneously shifting the phase of a corresponding converter of a converter station at the opposite side of the converter station where the non-fault converter is positioned;
after the preset time, the phase shifting of the non-fault converter and the corresponding converter of the pair of side converter stations is finished, and the normal operation is recovered.
4. The method for isolating the fault of the single converter of the extra-high voltage converter station according to claim 3, characterized in that: the preset time is 200 ms.
5. The method for isolating the fault of the single converter of the extra-high voltage converter station according to claim 3, characterized in that: when the converter station is a rectifier station, the phase shifting comprises: the converter valve firing angle of the rectifying station is shifted from 15 ° to 164 °.
6. The method for isolating the fault of the single converter of the extra-high voltage converter station according to claim 3, characterized in that: when the converter station is an inverter station, the phase shifting comprises: and moving the converter valve firing angle of the inversion station from 140 degrees to 164 degrees.
7. The method for isolating the fault of the single converter of the extra-high voltage converter station according to claim 1, characterized by comprising the following steps: the cathode circuit breaker, the anode circuit breaker and the parallel circuit breaker are all rapid circuit breakers which can reliably switch off within 50ms and can reliably switch on within 10 ms.
8. A computer-readable storage medium characterized by: the computer readable storage medium having stored thereon computer program instructions; the computer program instructions, when executed by a processor, implement the method for isolating the single converter fault of the extra-high voltage converter station according to any one of claims 1 to 7.
9. The utility model provides an isolation system of extra-high voltage converter station single converter trouble which characterized in that includes: the computer-readable storage medium of claim 8.
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