A resistance-inductive current-limiting hybrid high-voltage direct-current circuit breaker topology and a control method thereof

Abstract

A resistance and inductance current-limiting hybrid high-voltage direct-current circuit breaker topology and a control method thereof. The current-carrying branch of the topology is composed of a UFD and a load transfer switch LCS in series, and the two ends are respectively connected with DC line interfaces. The commutation branch is divided into two pairs, and each group of commutation branch is composed of a thyristor and a plurality of diodes in series. The transfer branch is composed of an IGBT and a thyristor in series. The current-limiting branch is composed of three parallel branches, including a branch composed of a thyristor, a plurality of diodes in series, and a reverse-parallel thyristor connected with a capacitor in series, a reverse-parallel thyristor branch, and a branch composed of an inductor connected with a resistor in parallel and a thyristor in series. The charging branch is composed of a capacitor connected with a thyristor in series and grounded. The breaking branch is composed of an IGBT and a metal oxide arrester MOA in parallel. Based on the thyristor commutation cooperation, the use of a large number of thyristors is reduced, and the cost is reduced under the characteristics of meeting the voltage and current resistance.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of electrical equipment, in particular to a resistance and inductance current limiting type hybrid high voltage direct current circuit breaker based on thyristor commutation cooperation. BACKGROUND

[0002] With the increasing proportion of renewable energy, great influence is generated on the existing power system, especially on the traditional high voltage alternating current transmission. Due to the intermittence and volatility of renewable energy, the traditional high voltage alternating current transmission still cannot fully meet the transmission requirements. Compared with the traditional high voltage alternating current transmission, the high voltage direct current transmission has many advantages such as fast response speed, low loss and good stability, and has developed rapidly in recent years. However, the low impedance and low inertia characteristics of the direct current transmission result in that the current rapidly rises in a very short time when a fault occurs, and if the fault is not cleared in time, the power system will be seriously endangered. The traditional hybrid high voltage direct current circuit breaker has a series of defects such as slow fault clearing speed, poor current limiting effect, short service life and high cost.

[0003] In view of the problems of the above-mentioned traditional hybrid high voltage direct current circuit breaker, the present application provides a resistance and inductance current limiting type hybrid high voltage direct current circuit breaker topology based on thyristor commutation cooperation and a control method thereof. SUMMARY

[0004] The present application provides a resistance and inductance current limiting type hybrid high voltage direct current circuit breaker topology and a control method thereof, based on thyristor commutation cooperation, reduces the use of a large number of thyristors and reduces the cost under the characteristics of withstand voltage and current.

[0005] A resistance and inductance current limiting type hybrid high voltage direct current circuit breaker topology, comprising: a current carrying branch, a commutation branch, a transfer branch, a current limiting branch, a charging branch and an opening branch.

[0006] The current carrying branch is connected to the DC line interfaces at both ends, and the current carrying branch is connected in series with a mechanical switch UFD and a load transfer switch LCS, wherein the load transfer switch LCS is formed by two groups of IGBTs in anti-series connection.

[0007] The commutation branch has a total of four groups, each group of the commutation branch is connected in series with a thyristor and a plurality of diodes, the four groups of the commutation branch are arranged in the upward direction of the current outlet and are divided into two sides, the commutation branches on the same side are connected end to end, the commutation branches on the different sides are directly connected, and the end-to-end connection positions on each side are connected to the corresponding interfaces of the DC line, and the commutation branch forms a bridge structure.

[0008] The transfer branch is connected in parallel with a plurality of IGBT groups and a thyristor connected in series, and is connected inside the bridge structure of the commutation branch.

[0009] The current limiting branch, in parallel with the transfer branch, is composed of three parallel sub-branches, the first sub-branch is a sub-branch in which thyristors and a plurality of diodes are connected in series and then the thyristors are connected in anti-parallel, and the thyristors are connected with a capacitor in series, the second sub-branch is an anti-parallel thyristor sub-branch, and the third sub-branch is a sub-branch in which an inductor is connected in parallel with a resistor and then the inductor is connected in series with a thyristor;

[0010] The charging branch is composed of a capacitor and a thyristor connected in series with the ground, and is connected to the upper end of the capacitor of the first current limiting branch.

[0011] The breaking branch is composed of an IGBT group T8 and a metal oxide arrester MOA connected in parallel, and is connected in series with the current limiting branch and then connected in parallel with the commutation branch inside the bridge.

[0012] Preferably, the commutation branch of the application has four groups, respectively Q1, Q2, Q3 and Q4, and the number of diodes connected in series with the current limiting branch in each group needs to be determined according to the actual maximum voltage and current.

[0013] Preferably, in the transfer branch of the application, the IGBT group T3 and the thyristor T2 are connected in series, and then form a current path with the breaking branch IGBT group T8.

[0014] Preferably, the charging branch of the application is connected to the upper end of the capacitor C1 of the first current limiting branch, and then the capacitor C2 and the thyristor T9 are connected in series with the ground, and the pressure of the capacitor C2 of the charging branch needs to be determined according to the pressure of the capacitor C1 of the current limiting branch.

[0015] Preferably, in the third sub-branch of the current limiting branch of the application, the inductor L1 and the resistor R1 are connected in parallel and then connected in series with the thyristor T7, and the thyristor T6 of the second sub-branch is connected in anti-parallel on the third sub-branch to form a bypass loop, and after the thyristor T4 of the first sub-branch is naturally turned off, the thyristor T5 and the capacitor C1 are connected in series with the third sub-branch to form a discharge loop.

[0016] Based on the control method of the resistance-inductance current limiting type hybrid high-voltage DC circuit breaker topology of the application, the circuit breaker works in the following three modes:

[0017] If placed at the left end of the DC transmission line, that is, the current direction is to the right, first, the capacitor of the circuit breaker is pre-charged, the commutation branch Q1, the IGBT group T3 and the thyristor T2 in the transfer branch, and the thyristor T9 in the charging branch are turned on, and after the charging is completed, the commutation branch Q1 and the thyristor T9 are naturally turned off.

[0018] Fault clearing mode: when detecting abnormal current, send fault clearing command to circuit breaker, immediately turn on commutator branch Q1 and commutator branch Q4 of circuit breaker, thyristor T2 of transfer branch, IGBT group T8 of breaking branch, turn off current-carrying branch, current is quickly transferred from current-carrying branch to transfer branch, at the same time, quickly open mechanical switch K1, and complete opening after reaching rated opening distance; continue to turn on thyristor T4 of the first branch of current limiting branch, capacitor C1 starts to discharge, thyristor T2 is turned off after bearing reverse voltage, current is gradually transferred to the third branch of current limiting branch under the action of capacitor C1 charging current gradually decreasing to the natural turn-off of thyristor T4; after the complete input of current limiting, if the system fault determination is completed, the circuit breaker receives the fault clearing command, then the IGBT group T8 of the breaking branch is turned off, the MOA is put into the breaking process, and the inductance and resistance are bypassed by the second branch T6 of the current limiting branch; due to the non-linear characteristics of MOA, the current is quickly reduced, and when the current is reduced to zero, the MOA presents high resistance state, and the fault clearing is completed; in order to release the energy of the bypassed inductance and resistance of the current limiting branch, the thyristor T5 of the second branch of the current limiting branch is turned on, and the thyristor T6 is turned off under the reverse voltage of the capacitor C1 which has been reversely charged, and the thyristor T5 of the first branch of the current limiting branch and the capacitor C1 form a discharge circuit in series with the third branch;

[0019] Current limiting recovery mode: if the system determines that fault clearing is not required, current recovery is required, after the circuit breaker receives the current limiting recovery command, the thyristor T2 of the transfer branch and the thyristor T6 of the second branch of the current limiting branch are turned on, the inductance and resistance of the current limiting branch are bypassed, and the current is transferred from the third branch of the current limiting branch to the transfer branch; then the UFD is closed, the current-carrying branch is turned on after closing is completed, the IGBT group T3 of the transfer branch is turned off, at this time, the current has been completely recovered to the current-carrying branch, and then the thyristor T5 of the second branch of the current limiting branch is turned on to discharge the inductance;

[0020] Maintenance power-off mode: if the line needs to be maintained, the system sends a line maintenance command to the circuit breaker, and after the current is transferred to the transfer branch, the circuit breaker does not need to be limited, directly waits for the UFD to be opened, the IGBT group T8 of the breaking branch is turned off, and the MOA is put into the breaking process.

[0021] The technical scheme is adopted in the application, and the application has the following advantages compared with the prior art:

[0022] 1. The third branch of the current limiting branch of the application adopts current limiting reactor and current limiting resistor in parallel to suppress current rise; the second branch increases a group of thyristors T6 to form a loop to bypass the current limiting inductor and resistor, thereby reducing the energy consumption burden of MOA and prolonging the service life of MOA; the first branch capacitor C1 and thyristor T5 are connected in series to provide an energy dissipation loop for the current limiting inductor resistor.

[0023] 2. The transfer branch of the application is connected in series with IGBT group T3 and thyristor T2, which not only provides a current transfer path for fault removal, but also provides a temporarily controllable path for current limiting recovery.

[0024] 3. The charging branch of the application uses thyristor and capacitor C2 connected to ground, and the size of C2 can be changed to flexibly change the voltage of C1 to adapt to the actual requirements of the circuit breaker.

[0025] 4. The commutation branch and the current limiting branch of the application use a thyristor and diode group in series to replace the traditional pure thyristor group, which reduces the use of a large number of thyristors and reduces costs while meeting the voltage and current resistance characteristics.

[0026] 5. There are three working modes: abnormal current, fault removal mode and current limiting recovery mode; normal state needs to be repaired, and there is a repair power-off mode; the three working modes of the circuit breaker can flexibly meet the basic working requirements of the DC power transmission project. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 The figure is a schematic diagram of the circuit topology of the application.

[0028] Figure 2 The figure is a schematic diagram of the current loop when the application is in normal operation.

[0029] Figure 3 The figure is a schematic diagram of the pre-charging current loop of the built-in capacitor of the application.

[0030] Figure 4 The figure is a schematic diagram of the current loop of each operation sequence when the DC circuit breaker of the application works in fault removal mode.

[0031] Figure 5 The figure is a schematic diagram of the current loop of each operation sequence when the DC circuit breaker of the application works in current limiting recovery mode.

[0032] Figure 6 The figure is a schematic diagram of the current loop of each operation sequence when the DC circuit breaker of the application works in repair power-off mode. DETAILED DESCRIPTION

[0033] The application proposes a resistance-inductance current limiting type hybrid high-voltage DC circuit breaker topology and a control method thereof, which will be further described in detail below with reference to the accompanying drawings.

[0034] As shown in Figure 1 The blocking and current-limiting hybrid HVDC circuit breaker topology of the present application mainly contains six branches: current-carrying branch, commutation branch, transfer branch, current-limiting branch, charging branch and breaking branch. Among them, the current-carrying branch is in series with UFD and LCS, and the two ends are respectively connected with the DC line interface; the commutation branch is totally four groups, which are divided into two pairs, and each group of commutation branch is in series with thyristor and multiple diodes; the transfer branch is in series with IGBT and thyristor; the current-limiting branch is composed of three parallel sub-branches, including a sub-branch in series with thyristor and multiple diodes, and then in anti-parallel with thyristor and in series with capacitor, an anti-parallel thyristor sub-branch, and a sub-branch in series with inductor and resistor and then in series with thyristor; the charging branch is in series with capacitor and thyristor and connected with ground; the breaking branch is in parallel with IGBT and metal oxide arrester MOA. At the same time, the control mode of the circuit breaker topology is provided.

[0035] The current-carrying branch, the two ends are respectively connected with the DC line interface, and the current-carrying branch is in series with mechanical switch UFD (K1) and load transfer switch LCS, wherein the load transfer switch LCS is composed of IGBT group T 1a and IGBT group T 1b anti-serially connected;

[0036] The commutation branch is totally four groups, which are respectively Q1, Q2, Q3 and Q4, each group of commutation branch is in series with thyristor and multiple diodes, and the number of diodes in series with each group of commutation branch and current-limiting branch needs to be determined according to the actual maximum voltage and current. The four groups of commutation branches are arranged in the upward direction of the current outlet and are divided into two sides, the commutation branches on the same side are connected end to end, the commutation branches on the different sides are directly connected, and the end-to-end connection places on each side are respectively connected to the corresponding interfaces of the DC line, and the whole commutation branch forms a bridge structure;

[0037] The transfer branch is in series with IGBT group T3 and thyristor T2, and is connected in parallel inside the bridge structure of the commutation branch, and forms a current path with the breaking branch IGBT group T8;

[0038] The current-limiting branch is in parallel with the transfer branch and is composed of three parallel sub-branches, the first sub-branch is a sub-branch in series with thyristor and multiple diodes, and then in anti-parallel with thyristor and in series with capacitor, the second sub-branch is an anti-parallel thyristor sub-branch, and the third sub-branch is a sub-branch in series with inductor and resistor and then in series with thyristor. The structure is that the inductor L1 and the resistor R1 in the third sub-branch of the current-limiting branch are connected in parallel and in series with a thyristor T7, and the thyristor T6 in the second sub-branch is anti-parallel connected on the third sub-branch to form a bypass loop, and after the natural turn-off of the T4 in the first sub-branch, T5 and C1 are in series with the third sub-branch to form a energy dissipation loop;

[0039] The charging branch is connected to the upper end of the capacitor C1 of the first current limiting branch, and is connected to the ground in series with the capacitor C2 and the thyristor T9, and the pressure of the capacitor needs to be determined according to the pressure of the capacitor C1 of the current limiting branch.

[0040] The opening branch is formed by the parallel connection of the IGBT group T8 and the metal oxide lightning arrester MOA, and is connected in series to the current limiting branch and forms a parallel branch with the current limiting branch and is connected to the inside of the bridge of the commutation branch.

[0041] The control method of the thyristor commutation cooperation-based resistance-inductance current limiting type hybrid high-voltage DC circuit breaker topology can work in the following three modes:

[0042] If the DC circuit breaker is placed at the left end of the DC transmission line, that is, the current direction is to the right, the capacitor of the circuit breaker is pre-charged first, the commutation branch Q1, the IGBT group T3 and the thyristor T2 in the transfer branch, and the thyristor T9 in the charging branch are turned on, and the commutation branch Q1 and the thyristor T9 are naturally turned off after the charging is completed.

[0043] The fault clearing mode is as follows: when an abnormal current is detected, a fault clearing command is sent to the circuit breaker, the commutation branches Q1 and Q4 of the circuit breaker, the thyristor T2 of the transfer branch, and the IGBT group T8 of the opening branch are immediately turned on, the current is quickly transferred from the current-carrying branch to the transfer branch, and the mechanical switch K1 is quickly opened, and the opening is completed after the rated opening distance is reached; the thyristor T4 of the first branch of the current limiting branch is continuously turned on, the capacitor C1 starts to discharge, the thyristor T2 is turned off after bearing the reverse voltage, the current is transferred to the first branch of the current limiting branch, and the capacitor C1 starts to charge reversely; under the action of the forward voltage, the thyristor T7 is turned on, the inductor L1 and the resistor R1 are put into operation, at this time, the charging current of the capacitor C1 gradually decreases to the natural turn-off of the thyristor T4, and the current is gradually transferred to the third branch of the current limiting branch; after the current limiting is completely put into operation, if the system fault determination is completed and the circuit breaker receives the fault clearing command, the IGBT group T8 of the opening branch is turned off, the MOA is put into operation for disconnection, and the second branch T6 of the current limiting branch is turned on to bypass the inductor and the resistor; due to the non-linear characteristics of the MOA, the current rapidly decreases, and when the current decreases to zero, the MOA presents a high resistance state, and the fault clearing is completed; in order to release the energy of the bypass inductor and resistor of the current limiting branch, the thyristor T5 of the second branch of the current limiting branch is turned on to put the capacitor C1 into operation, at this time, the thyristor T6 is turned off under the reverse voltage of the capacitor C1 which has been reversely charged, and the thyristor T5 of the first branch of the current limiting branch and the capacitor C1 are connected in series with the third branch to form a discharge circuit.

[0044] Current limiting recovery mode: if the system judges that fault clearing is not needed, current recovery needs to be carried out, after the circuit breaker accepts the current limiting recovery command, the thyristor T2 of the transfer branch and the thyristor T6 of the second branch of the current limiting branch are turned on, the inductance and the resistance of the current limiting branch are bypassed, and the current is transferred from the third branch of the current limiting branch to the transfer branch; then the UFD is closed, the current carrying branch is turned on after the closing is completed, the IGBT group T3 of the transfer branch is turned off, at this time the current has been completely recovered to the current carrying branch, then the thyristor T5 of the second branch of the current limiting branch is turned on to discharge the inductance of the capacitor C1.

[0045] Maintenance power-off mode: if the line needs to be maintained, the system sends a line maintenance command to the circuit breaker, after the current is transferred to the transfer branch, the circuit breaker does not need to be limited, directly waits for the UFD to be opened, the IGBT group T8 of the breaking branch is turned off, and the MOA is put into the breaking process.

[0046] Referring to the accompanying drawings Figure 1 The application proposes a kind of based on thyristor commutation cooperation's resistance-inductance current limiting type hybrid high-voltage direct-current circuit breaker topology detailed schematic diagram, and topology structure mainly includes 6 branches: current carrying branch, commutation branch, transfer branch, current limiting branch, charging branch and breaking branch.

[0047] Referring to the accompanying drawings Figure 2 In one example, the direct-current circuit breaker is placed at the left end of the direct-current transmission line, and the current flows directly from the left end of the circuit breaker to the right end of the circuit breaker through the current carrying branch when the direct-current transmission line is normally operated, and the current carrying branch includes mechanical switch K1 and IGBT group T1.

[0048] Referring to the accompanying drawings Figure 3 The application pre-charges the internal capacitor before any working mode, turns on the commutation branch Q1, the IGBT group T3, the thyristor T2 and the thyristor T9, the current flows through the commutation branch Q1, the transfer branch T3, the thyristor T2, the capacitor C1 of the current limiting branch and the thyristor T9 and the capacitor C2 of the charging branch to ground, and the capacitor C1 is charged, at this time the voltage across the capacitor C1 is negative on the top and positive on the bottom. According to the actual current limiting requirement, the size of the capacitor C2 can be changed to change the voltage across the capacitor C1.

[0049] Referring to the accompanying drawings Figure 4 The direct-current circuit breaker of the application works in fault clearing mode. The dark path is the current flow path at each step timing:

[0050] The accompanying drawings Figure 4(a), when the abnormal current is detected, a fault clearing command is sent to the DC circuit breaker, the commutation branch Q1 and the commutation branch Q4 of the circuit breaker are turned on immediately, the thyristor T2 of the transfer branch, the IGBT group T8 of the breaking branch are turned on, the load transfer switch LCS of the current carrying branch is turned off, the current is quickly transferred from the current carrying branch to the transfer branch, and the mechanical switch K1 is quickly opened, and the opening is completed after the rated opening distance is reached;

[0051] Figure 2 is a schematic diagram of the working principle of the DC circuit breaker according to the present application; Figure 4 (b), the thyristor T4 of the first branch of the current limiting branch is turned on, the capacitor C1 starts to discharge, the thyristor T2 is turned off after bearing the reverse voltage, the current is transferred to the first branch of the current limiting branch, and the capacitor C1 starts to be reversely charged, at this time, the voltage between the two ends of the capacitor C1 is positive on the top and negative on the bottom;

[0052] Figure 3 is a schematic diagram of the working principle of the DC circuit breaker according to the present application; Figure 4 (c), the thyristor T7 is turned on under the action of the forward voltage, the current limiting inductor L1 and the resistor R1 are put into operation, at this time, the charging current of the capacitor C1 gradually decreases to the natural turn-off of the thyristor T4, and the current is gradually transferred to the third branch of the current limiting branch;

[0053] Figure 4 is a schematic diagram of the working principle of the DC circuit breaker according to the present application; Figure 4 (d), after the current limiting is completely put into operation, that is, the current completely flows through the third branch of the current limiting branch, waiting for receiving the fault clearing command;

[0054] Figure 5 is a schematic diagram of the working principle of the DC circuit breaker according to the present application; Figure 4 (e), at this time, if the system judges that the fault needs to be cleared, the circuit breaker receives the fault clearing command, the T8 of the breaking branch is turned off, the MOA is put into operation for breaking, the thyristor T6 of the second branch of the current limiting branch is turned on to bypass the inductor and the resistor, due to the non-linear characteristics of the MOA, the current rapidly decreases, when the current decreases to zero, the MOA presents a high resistance state, and the fault clearing is completed;

[0055] Figure 6 is a schematic diagram of the working principle of the DC circuit breaker according to the present application; Figure 4 (f), in order to release the energy of the bypassed inductor and resistor of the current limiting branch, the thyristor T5 of the second branch of the current limiting branch is turned on to put the capacitor C1 into operation, at this time, the thyristor T6 is turned off under the reverse voltage of the capacitor C1 which has been reversely charged, the first branch T5 and the capacitor C1 of the current limiting branch are connected in series with the third branch to form an energy releasing circuit.

[0056] Figure 7 is a schematic diagram of the working principle of the DC circuit breaker according to the present application; Figure 5 The present application works in a current limiting recovery mode. The dark path is the current flow path at each step timing:

[0057] Figure 8 is a schematic diagram of the working principle of the DC circuit breaker according to the present application; Figure 5 (a-d), the working timing steps based on the fault clearing mode are shown in Figure 2, if the circuit breaker completely enters the current limiting after that, the system judges that the fault does not need to be cleared, and the current recovery needs to be performed; Figure 4

[0058] Figure 9 is a schematic diagram of the working principle of the DC circuit breaker according to the present application.​Figure 5 (e), after the circuit breaker accepts the current limiting recovery command, the thyristor T2 of the transfer branch and the thyristor T6 of the second branch of the current limiting branch are turned on, the inductance and resistance of the current limiting branch are bypassed, and the current is transferred from the third branch of the current limiting branch to the transfer branch;

[0059] attached Figure 5 (f), then the K1 is closed, after the closing is completed, the load transfer switch LCS of the current carrying branch is turned on, the IGBT group T3 of the transfer branch is turned off, at this time the current has been completely recovered to the current carrying branch, and then the thyristor T5 of the second branch of the current limiting branch is turned on to discharge the inductance of the capacitor C1.

[0060] attached Figure 6 , the present application works in the maintenance power-off mode. The dark path is the current flow path at each step:

[0061] attached Figure 6 (a), if the line needs to be maintained and powered off, the system sends a line maintenance command to the circuit breaker, the circuit breaker transfers the current to the transfer branch, and the transfer step is based on the working time sequence step of the fault clearing mode as shown in the attached Figure 4 ;

[0062] attached Figure 6 (b), then without current limiting, directly after the disconnection is completed, the IGBT group T8 of the section branch is turned off to carry out the disconnection process.

[0063] The unexplained part of the present application is applicable to the prior art.

Claims

1. A control method of a resistance-restrained current-limiting hybrid HVDC circuit breaker topology, characterized in that, the circuit breaker topology comprises: a current-carrying branch, a commutation branch, a transfer branch, a current-limiting branch, a charging branch, and an opening branch; the current-carrying branch is connected to two DC line interfaces, and the current-carrying branch is connected in series with a mechanical switch UFD and a load transfer switch LCS, wherein the load transfer switch LCS is formed by two groups of anti-serial IGBTs; the commutation branch comprises four groups of commutation branches, each group of commutation branches is formed by a thyristor and a plurality of diodes connected in series, the four groups of commutation branches are arranged in the upward direction of the current outlet and are divided into two sides, the commutation branches on the same side are connected end to end, the commutation branches on the different sides are directly connected, and the ends of each side are connected to the corresponding interfaces of the DC line, and the commutation branches form a bridge structure; the transfer branch is formed by an IGBT group and a thyristor connected in series and is connected in parallel inside the bridge structure of the commutation branch; the current-limiting branch is connected in parallel with the transfer branch and comprises three parallel branches, the first branch is a branch formed by a thyristor and a plurality of diodes connected in series, an anti-parallel thyristor, and a capacitor connected in series, the second branch is an anti-parallel thyristor branch, and the third branch is a branch formed by an inductor connected in parallel with a resistor and a thyristor connected in series; the charging branch is formed by a capacitor and a thyristor connected in series and grounded, and is connected to the upper end of the capacitor of the first current-limiting branch; the opening branch is formed by an IGBT group T8 and a metal oxide arrester MOA connected in parallel, and is connected in series to the current-limiting branch and then connected in parallel inside the bridge structure of the commutation branch; the circuit breaker works in the following three modes: if placed at the left end of the DC transmission line, the current direction is to the right, first, the capacitor of the circuit breaker is pre-charged, the commutation branch Q1, the IGBT group T3 and the thyristor T2 in the transfer branch, and the thyristor T9 in the charging branch are turned on, and after the charging is completed, the commutation branch Q1 and the thyristor T9 are naturally turned off; Fault clearing mode: when detecting abnormal current, send fault clearing command to circuit breaker, immediately turn on commutator branch Q1 and commutator branch Q4, thyristor T2 of transfer branch, IGBT group T8 of breaking branch, turn off current-carrying branch, current is quickly transferred from current-carrying branch to transfer branch, at the same time, quickly open mechanical switch K1, complete opening after reaching rated opening distance; continue to turn on thyristor T4 of the first branch of current limiting branch, capacitor C1 begins to discharge, thyristor T2 is turned off after bearing reverse voltage, current is transferred to the first branch of current limiting branch, capacitor C1 begins to charge reversely, thyristor T7 is turned on under the action of forward voltage, current limiting inductor L1 and resistor R1 are put into operation, at this time, the charging current of capacitor C1 gradually decreases to the natural turn-off of thyristor T4, and the current is gradually transferred to the third branch of current limiting branch; after the complete operation of current limiting, if the system fault determination is completed and the circuit breaker receives the fault clearing command, turn off IGBT group T8 of breaking branch, put MOA into operation for breaking, at the same time, turn on T6 of the second branch of current limiting branch to bypass inductor and resistor, due to the nonlinear characteristics of MOA, the current quickly decreases, when the current decreases to zero, MOA presents high resistance state, and the fault clearing is completed; in order to release the energy of bypass inductor and resistor of current limiting branch, turn on thyristor T5 of the second branch of current limiting branch to put capacitor C1 into operation, at this time, thyristor T6 is turned off under the reverse voltage of capacitor C1 which has been charged reversely, and thyristor T5 of the first branch of current limiting branch and capacitor C1 form a discharge circuit with the third branch in series; Current limiting recovery mode: if the system determines that fault clearing is not needed, current recovery is needed, after the circuit breaker receives the current limiting recovery command, turn on thyristor T2 of transfer branch and thyristor T6 of the second branch of current limiting branch to bypass inductor and resistor of current limiting branch, and transfer the current from the third branch of current limiting branch to transfer branch; then close UFD, after closing is completed, turn on current-carrying branch, turn off IGBT group T3 of transfer branch, at this time, the current has been completely recovered to current-carrying branch, then turn on thyristor T5 of the second branch of current limiting branch to put capacitor C1 into operation to discharge inductor; Maintenance power-off mode: if the line needs to be powered off for maintenance, the system sends line maintenance command to the circuit breaker, after the current is transferred to the transfer branch, the circuit breaker does not need to limit current, directly waits for the UFD to be opened, turns off IGBT group T8 of breaking branch and puts MOA into operation for breaking process.

2. The control method of the resistance current limiting hybrid HVDC circuit breaker topology according to claim 1, characterized in that, There are four groups of commutator branches, respectively Q1, Q2, Q3 and Q4, the number of diodes in series with each group of commutator branches and current limiting branches needs to be determined according to the actual maximum voltage and current.

3. The control method of the resistance current limiting hybrid HVDC circuit breaker topology according to claim 1, characterized in that, IGBT group T3 and thyristor T2 in transfer branch are connected in series, and then form a current path with IGBT group T8 of breaking branch.

4. The control method of the resistance current limiting hybrid HVDC circuit breaker topology according to claim 1, characterized in that, Capacitor C2 and thyristor T9 in charging branch are connected in series and grounded, charging branch is connected to the upper end of capacitor C1 of the first current limiting branch, then capacitor C2 and thyristor T9 are connected in series and grounded, the voltage borne by capacitor C2 needs to be determined according to the voltage borne by capacitor C1 of current limiting branch.

5. The control method of the resistance current limiting hybrid HVDC circuit breaker topology according to claim 1, characterized in that, The third branch of the current limiting branch is connected in parallel with the inductor L1 and the resistor R1, and is connected in series with the thyristor T7, and the second branch of the thyristor T6 is connected in anti-parallel on the third branch to form a bypass loop, and after the first branch of the thyristor T4 is naturally turned off, the thyristor T5 and the capacitor C1 are connected in series to form a energy discharge loop.

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