CN115459211A - Inductance-resistance current-limiting type hybrid high-voltage direct-current circuit breaker topology and control method thereof - Google Patents

Abstract

A resistance-inductance current-limiting type hybrid high-voltage direct-current circuit breaker topology and a control method thereof. The current-carrying branch of the topological structure is formed by connecting a UFD and a load transfer switch LCS in series, and two ends of the current-carrying branch are respectively connected with a direct current line interface; the phase change branches are divided into two pairs, and each phase change branch is formed by connecting a thyristor and a plurality of diodes in series; the transfer branch is formed by connecting an IGBT and a thyristor in series; the current limiting branch consists of three parallel branches, including one branch comprising a thyristor and several diodes connected serially and then connected parallelly with the thyristor and connected serially with the capacitor, one branch comprising an anti-parallel thyristor and one branch comprising an inductor connected parallelly with a resistor and then connected serially with the thyristor; the charging branch circuit is formed by connecting a capacitor and a thyristor in series and grounding; the breaking branch is formed by connecting an IGBT (insulated gate bipolar translator) and a metal oxide arrester MOA in parallel. Based on the matching of the phase change of the thyristors, the use of a large number of thyristors is reduced and the cost is reduced under the condition of meeting the characteristics of voltage resistance and current resistance.

Description

A resistance-inductance current-limiting hybrid HVDC circuit breaker topology and its control method

technical field

The invention relates to the field of electrical equipment, in particular to a resistance-inductance current-limiting hybrid high-voltage direct current circuit breaker based on thyristor commutation coordination.

Background technique

As the proportion of renewable energy continues to grow, it has had a great impact on the existing power system, especially the traditional high-voltage AC transmission has created a huge challenge. Due to the intermittency and volatility of renewable energy, traditional high-voltage AC transmission is still not fully capable of power transmission requirements. Compared with traditional high-voltage AC transmission, HVDC transmission has many advantages such as fast response, low loss, and good stability, and has developed rapidly in recent years. However, DC transmission has the characteristics of low impedance and low inertia, so that when a fault occurs, the current rises rapidly in a very short time. If the fault is not cleared in time, the power system will be seriously endangered. Traditional hybrid HVDC circuit breakers have a series of defects such as slow fault clearing speed, poor current limiting effect, short life, and high cost.

Aiming at the above-mentioned problems of the traditional hybrid high-voltage DC circuit breaker, the present invention proposes a topology and control method of a resistance-inductive current-limiting hybrid high-voltage DC circuit breaker based on thyristor commutation coordination.

Contents of the invention

The invention proposes a resistance-inductive current-limiting hybrid high-voltage DC circuit breaker topology and its control method. Based on the thyristor commutation coordination, it reduces the use of a large number of thyristors and reduces the cost under the characteristics of withstand voltage and current resistance.

A resistance-inductance current-limiting hybrid high-voltage DC circuit breaker topology, including: a current-carrying branch, a commutation branch, a transfer branch, a current-limiting branch, a charging branch, and a breaking branch;

Both ends of the current-carrying branch are respectively connected to the DC line interface, and at the same time, 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 reverse series;

There are four groups of commutation branches in total. Each group of commutation branches is composed of thyristors and several diodes connected in series. The commutation branches on the opposite sides are directly connected, and at the same time, the end-to-end connections on each side are respectively connected to the corresponding interfaces of the DC line, and the entire commutation branch forms a bridge structure;

The transfer branch is composed of several IGBT groups and thyristors connected in series, and connected in the bridge structure of the commutation branch;

The current-limiting branch is connected in parallel with the transfer branch and is composed of three parallel branches. The first branch is a branch consisting of a thyristor and a plurality of diodes connected in series and then an anti-parallel thyristor is connected in series with a capacitor. The second branch is an anti-parallel thyristor branch circuit, and the third branch is a branch circuit in which an inductance is connected in parallel with a resistance and then connected in series with the thyristor;

The charging branch is composed of a capacitor connected in series with a thyristor connected to the upper end of the capacitor of the first current-limiting branch;

The breaking branch is formed by parallel connection of IGBT group _T8 and metal oxide arrester MOA, connected in series to the current-limiting branch, and connected in series with the current-limiting branch at the same time and connected in parallel inside the bridge of the commutation branch.

Preferably, there are four groups of commutation branches in the present invention, which are respectively Q ₁ , Q ₂ , Q ₃ , and Q ₄ . Determined by voltage and current.

Preferably, the IGBT group T3 in the transfer branch _of the present invention is connected in series with the thyristor _T2 , and then forms a current path with the IGBT group _T8 in the breaking branch.

Preferably, the charging branch of the present invention 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 grounded in series, and the pressure of the charging branch capacitor _C2 needs to be according to the current-limiting branch. It is determined by the magnitude of the pressure on the capacitor C ₁ .

Preferably, in the third branch of the current _- limiting branch _of the present invention, the inductance L1 and the resistor R1 are connected in parallel and connected in series with the thyristor _T7 , and the thyristor _T6 of the second branch is antiparallel connected on the third branch to form Bypass loop, and after the thyristor _T4 of the first branch circuit is naturally turned off, the thyristor _T5 and the capacitor _C1 are connected in series with the third branch circuit to form an energy discharge circuit.

Based on the control method of the resistance-inductive current-limiting hybrid high-voltage DC circuit breaker topology of the present invention, the circuit breaker works in the following three modes:

If it is placed at the left end of the DC transmission line, that is, the current direction is to the right, firstly precharge the circuit breaker capacitor, turn on the commutation branch Q ₁ , the IGBT group T ₃ and the thyristor T ₂ in the transfer branch, and the charging branch The thyristor T ₉ in the circuit, after the charging is completed, the commutation branch Q ₁ and the thyristor T ₉ are naturally turned off;

Fault clearing method: When an abnormal current is detected, a fault clearing command is sent to the circuit breaker, and the commutation branch Q ₁ and Q ₄ of the circuit breaker are turned on immediately, the thyristor T ₂ of the transfer branch, and the breaking branch IGBT group T ₈ , turn off the current-carrying branch, the current is quickly transferred from the current-carrying branch to the transfer branch, and at the same time quickly open the mechanical switch K ₁ , and complete the opening after reaching the rated opening distance; continue to conduct current limiting The thyristor T ₄ of the first branch of the branch, the capacitor C ₁ starts to discharge, the thyristor T ₂ is turned off after being subjected to back pressure, the current is transferred to the first branch of the current limiting branch, and the capacitor C ₁ starts to reverse charge, and in the positive The thyristor T7 is turned _on under the action of the voltage, and the current _- limiting inductance L1 and resistor R1 are input. At this time, because the charging current _of the capacitor _C1 gradually decreases until the thyristor T4 is naturally turned off, the current is gradually transferred to the first current _- limiting branch. Three branches; after the current limiting is fully put into use, if the system fault judgment is completed at this time and the circuit breaker receives the fault clearing command, it will turn off the IGBT group _T8 of the breaking branch and put it into MOA for breaking, and at the same time turn on the current limiting branch The second branch _T6 of the road bypasses the inductance and resistance. Due to the nonlinear characteristics of the MOA, the current decreases rapidly. When the current drops to zero, the MOA presents a high-impedance state, and the fault is cleared. Bypass the inductance and resistance energy, turn _on the thyristor T5 of the second branch _of the current _- limiting branch and put it into the capacitor _C1 . _The thyristor T5 of the first branch of the branch circuit and the third branch of the capacitor _C1 are connected in series to form an energy discharge circuit;

Current limiting recovery mode: If the system judges that the fault is not needed to be cleared, and current recovery is required, the circuit breaker will turn on the thyristor T ₂ of the transfer branch and the thyristor T ₆ of the second branch of the current limiting branch after receiving the current limiting recovery command. Bypass the inductor and resistor of the current-limiting branch, and transfer the current from the third branch of the current-limiting branch to the transfer branch; then close the UFD, turn on the current-carrying branch after closing, and turn off the IGBT of the transfer branch Group T ₃ , at this time the current has completely recovered to the current-carrying branch, and then the thyristor T ₅ of the second branch of the current-limiting branch is turned on, and the capacitor C ₁ is used to discharge the energy of the inductor;

Maintenance and power-off mode: If the line needs to be repaired and powered off, the system will send a line maintenance command to the circuit breaker. After the current is transferred to the transfer branch, the circuit breaker does not need to limit the current. IGBT group T ₈ is put into MOA for breaking process.

The present invention adopts above-mentioned technical scheme, does not want to have following advantage compared with prior art:

1. The third branch of the current-limiting branch of the present invention adopts a parallel connection of a current-limiting reactance and a current-limiting resistor to suppress the current rise; the second branch adds a group of thyristors _T6 to form a loop to bypass the current-limiting inductance and resistance to reduce MOA The burden of energy consumption prolongs the service life of the MOA; the first branch capacitor C ₁ and the thyristor T ₅ are connected in series to provide an energy leakage circuit for the current-limiting inductance resistor.

2. The transfer branch of the present invention connects the IGBT group T ₃ and the thyristor T ₂ in series, which can not only provide a current transfer path for fault removal, but also provide a temporary controllable path for current limiting recovery.

3. The charging branch of the present invention uses a thyristor and a capacitor _C2 to be grounded. Changing the size of _C2 can flexibly change the voltage of _C1 to meet the actual requirements of the circuit breaker.

4. In the commutation branch and current limiting branch of the present invention, thyristor series diode groups are used to replace traditional pure thyristor groups, which reduces the use of a large number of thyristors and reduces the cost under the characteristics of voltage resistance and current resistance.

5. There are three working modes: to deal with abnormal current, there are fault clearing mode and current limiting recovery mode; to deal with the normal state that requires maintenance and power-off, there is a maintenance power-off mode; the three working modes of this circuit breaker can flexibly deal with the DC transmission project. Basic job requirements.

Description of drawings

FIG. 1 is a schematic diagram of the circuit topology of the present invention.

Fig. 2 is a schematic diagram of the current loop during normal operation of the present invention.

FIG. 3 is a schematic diagram of a current circuit for precharging a built-in capacitor in the present invention.

FIG. 4 is a schematic diagram of the current circuit of each operating sequence of the DC circuit breaker of the present invention working in the fault clearing mode.

Fig. 5 is a schematic diagram of the current circuit of each operating time sequence of the DC circuit breaker of the present invention working in the current limiting recovery mode.

Fig. 6 is a schematic diagram of the current circuit of each operation sequence when the DC circuit breaker of the present invention works in the maintenance and power-off mode.

detailed description

The present invention proposes a resistance-inductive current-limiting hybrid high-voltage DC circuit breaker topology and its control method. The present invention will be further elaborated below in conjunction with the accompanying drawings.

As shown in Figure 1, the topological structure of the resistive-inductive current-limiting hybrid HVDC circuit breaker of the present invention mainly includes six branches: current-carrying branch, commutation branch, transfer branch, current-limiting branch, charging branch road and break branch. Among them, the current-carrying branch is connected in series with UFD and LCS, and the two ends are respectively connected to the DC line interface; there are four groups of commutation branches, divided into two pairs, and each group of commutation branches is composed of thyristors and multiple diodes in series; the transfer branch is composed of The IGBT and the thyristor are connected in series; the current-limiting branch is composed of three parallel branches, including a thyristor and a plurality of diodes in series and anti-parallel thyristors and capacitors in series at the same time, an anti-parallel thyristor branch, and a branch composed of Inductors connected in parallel with resistors and thyristors connected in series; charging branches connected in series with capacitors and thyristors; breaking branches connected in parallel with IGBTs and metal oxide arresters MOA. At the same time, the invention provides a way of controlling this circuit breaker topology.

Both ends of the current-carrying branch are respectively connected to the DC line interface, and at the same time, the current-carrying branch is connected in series with a mechanical switch UFD(K ₁ ) and a load transfer switch LCS, wherein the load transfer switch LCS is composed of IGBT group T _1a and IGBT group T _1b anti-series;

There are four groups of commutation branches in total, namely Q ₁ , Q ₂ , Q ₃ , and Q ₄ . Each group of commutation branches is composed of thyristors and multiple diodes connected in series. Each group of commutation branches and current limiting The number of diodes connected in series should 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 distributed on both sides. The commutation branches on the same side are connected end to end, and the commutation branches on different sides are directly connected. At the same time, the end to end connection of each side is respectively connected to the corresponding interface of the DC line. , the entire commutation branch constitutes a bridge structure;

_The transfer branch is connected in series with the IGBT group T3 and the thyristor T2, and connected in the bridge structure _of the commutation branch, and then forms a current path with the breaking branch IGBT group _T8 ;

The current-limiting branch is connected in parallel with the transfer branch and consists of three parallel branch circuits. The first branch is a branch circuit in which a thyristor and a plurality of diodes are connected in series and anti-parallel thyristors are connected in series with a capacitor at the same time. The second branch It is an anti-parallel thyristor branch circuit, and the third branch is a branch circuit in which an inductance is connected in parallel with a resistance and the thyristor is connected in series. Its structure is that in the third branch of the current _- limiting branch, the inductance L1 and the resistor R1 are connected in parallel and connected in series with _a thyristor T7, and the thyristor _T6 of the second branch is anti _- parallel connected on the third branch to form a bypass circuit , and after the first branch _T4 is naturally turned off, _T5 and _C1 are connected in series with the third branch to form an energy discharge circuit;

The charging branch 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 grounded in series. ;

The breaking branch is formed by parallel connection of IGBT group _T8 and metal oxide arrester MOA, connected in series to the current-limiting branch, and at the same time forms a parallel branch with the current-limiting branch and is connected inside the commutation branch bridge.

According to the control method based on thyristor commutation coordination, resistance-inductance current-limiting hybrid high-voltage DC circuit breaker topology, the circuit breaker can work in the following three modes:

If the DC circuit breaker of the present invention is placed at the left end of the DC transmission line, that is, the current direction is to the right, firstly, the capacitor of the circuit breaker is precharged, and the commutation branch Q ₁ , the IGBT group T ₃ and the IGBT group in the transfer branch are turned on. The thyristor T ₂ and the thyristor T ₉ in the charging branch, after the charging is completed, the commutation branch Q ₁ and the thyristor T ₉ are naturally turned off;

Fault clearing method: When an abnormal current is detected, a fault clearing command is sent to the circuit breaker, and the commutation branch Q ₁ and Q ₄ of the circuit breaker are turned on immediately, the thyristor T ₂ of the transfer branch, and the breaking branch IGBT group T ₈ , turn off the current-carrying branch, the current is quickly transferred from the current-carrying branch to the transfer branch, and at the same time quickly open the mechanical switch K ₁ , and complete the opening after reaching the rated opening distance; continue to conduct current limiting The thyristor T ₄ of the first branch of the branch, the capacitor C ₁ starts to discharge, the thyristor T ₂ is turned off after being subjected to back pressure, the current is transferred to the first branch of the current limiting branch, and the capacitor C ₁ starts to reverse charge, and in the positive The thyristor T7 is turned _on under the action of the voltage, and the current _- limiting inductance L1 and resistor R1 are input. At this time, because the charging current _of the capacitor _C1 gradually decreases until the thyristor T4 is naturally turned off, the current is gradually transferred to the first current _- limiting branch. Three branches; after the current limiting is fully put into use, if the system fault judgment is completed at this time and the circuit breaker receives the fault clearing command, it will turn off the IGBT group _T8 of the breaking branch and put it into MOA for breaking, and at the same time turn on the current limiting branch The second branch _T6 of the road bypasses the inductance and resistance. Due to the nonlinear characteristics of the MOA, the current decreases rapidly. When the current drops to zero, the MOA presents a high-impedance state, and the fault is cleared. Bypass the inductance and resistance energy, turn _on the thyristor T5 of the second branch _of the current _- limiting branch and put it into the capacitor _C1 . _The thyristor T5 of the first branch of the branch circuit and the third branch of the capacitor _C1 are connected in series to form an energy discharge circuit;

Current limiting recovery mode: If the system judges that the fault is not needed to be cleared, and current recovery is required, the circuit breaker will turn on the thyristor T ₂ of the transfer branch and the thyristor T ₆ of the second branch of the current limiting branch after receiving the current limiting recovery command. Bypass the inductor and resistor of the current-limiting branch, and transfer the current from the third branch of the current-limiting branch to the transfer branch; then close the UFD, turn on the current-carrying branch after closing, and turn off the IGBT of the transfer branch Group T ₃ , at this time the current has completely recovered to the current-carrying branch, and then the thyristor T ₅ of the second branch of the current-limiting branch is turned on, and the capacitor C ₁ is used to discharge the energy of the inductor;

Maintenance and power-off mode: If the line needs to be repaired and powered off, the system will send a line maintenance command to the circuit breaker. After the current is transferred to the transfer branch, the circuit breaker does not need to limit the current. IGBT group T ₈ is put into MOA for breaking process.

Referring to accompanying drawing 1, the present invention proposes a detailed schematic diagram of the topology of a resistive-inductive current-limiting hybrid high-voltage DC circuit breaker based on thyristor commutation coordination. The topology mainly includes 6 branches: current-carrying branch, commutation branch, Transfer branch, current limiting branch, charging branch and breaking branch.

Referring to accompanying drawing 2, in one example, the DC circuit breaker is placed on the left end of the DC transmission line, and the present invention directly flows through the current-carrying branch from the left end of the circuit breaker to the right end of the circuit breaker when the DC transmission line is in normal operation, and the current-carrying branch Including mechanical switch K ₁ and IGBT group T ₁ .

Referring to the accompanying drawing 3, before any working mode, the present invention precharges its internal capacitance, turns on the commutation branch Q ₁ , IGBT group T ₃ , thyristor T ₂ , and thyristor T ₉ , and the current flows through the left end of the DC circuit breaker. The commutation branch Q ₁ , the transfer branch T ₃ , the thyristor T ₂ , the capacitor C ₁ of the current limiting branch, the thyristor T ₉ and the capacitor C ₂ of the charging branch are grounded, and the capacitor C ₁ is charged. At this time, the capacitor C ₁ The voltage at both ends is negative at the top and positive at the bottom. According to the actual current limiting requirement, the size of the capacitor _C2 can be changed, thereby changing the voltage across the capacitor _C1 .

Referring to accompanying drawing 4, the DC circuit breaker of the present invention works in the fault clearing mode. The dark paths are the current flow paths for each step sequence:

In Fig. 4(a), when an abnormal current is detected, a fault clearing command is sent to the DC circuit breaker, and the commutation branch Q ₁ , commutation branch Q ₄ , and the thyristor T ₂ of the transfer branch are immediately turned on. 1. The IGBT group T ₈ of the breaking branch is turned off, and the load transfer switch LCS _of the current-carrying branch is turned off. After the opening is completed;

As shown in Figure 4(b), the thyristor T ₄ of the first branch of the current-limiting branch is turned on, the capacitor C ₁ starts to discharge, the thyristor T ₂ is turned off after being subjected to back pressure, and the current is transferred to the first branch of the current-limiting branch , the capacitor C ₁ starts to reversely charge, and the voltage at both ends of the capacitor C ₁ is positive at the top and negative at the bottom;

Figure 4(c) turns on the thyristor T ₇ under the action of the forward voltage, and puts in the current-limiting inductance L ₁ and the resistor R ₁ . At this time, since the charging current of the capacitor C ₁ gradually decreases until the thyristor T ₄ is naturally turned off, The current is gradually transferred to the third branch of the current limiting branch;

Figure 4(d), after the current limiting is fully put into use, that is, the current completely flows through the third branch of the current limiting branch, waiting to receive the fault clearing command;

Figure 4(e), at this time, if the system judges that the fault needs to be cleared, and the circuit breaker receives the fault clearing command, it will turn off the breaking branch T ₈ and put it into MOA for breaking, and at the same time turn on the second current limiting branch The thyristor T ₆ of the branch bypasses the inductance and resistance. Due to the nonlinear characteristics of the MOA, the current decreases rapidly. When the current drops to zero, the MOA presents a high-impedance state, and the fault is cleared;

Figure 4(f), in order to release the bypassed inductance and resistance energy of the current-limiting branch, turn on the thyristor T ₅ of the second branch of the current-limiting branch and input the capacitor C ₁ , at this time, the thyristor T ₆ has been reversed The reverse pressure of the charged capacitor C ₁ turns off, and the first branch T ₅ of the current limiting branch is connected in series with the third branch of the capacitor C ₁ to form an energy discharge circuit.

With reference to accompanying drawing 5, the present invention works in the current limiting recovery mode. The dark path is the current flow path of each step sequence:

Figure 5(a-d), the working sequence steps based on the fault clearing method are shown in Figure 4(a-d), if the circuit breaker fully enters the current limit, the system judges that the fault clearing is not needed, and the current recovery is required;

As shown in Figure 5(e), after the circuit breaker accepts the current-limiting recovery command, it turns on the thyristor T2 of the transfer branch and the thyristor _T6 of the _second branch of the current-limiting branch, bypassing the inductor and resistor of the current-limiting branch, The current is transferred from the third branch of the current limiting branch to the transfer branch;

Figure 5(f), then close K ₁ , turn on the load transfer switch LCS of the current-carrying branch after closing, and turn off the IGBT group T ₃ of the transfer branch, at this time the current has completely recovered to the current-carrying branch Afterwards, the thyristor T ₅ of the second branch of the current-limiting branch is turned on, and the capacitor C ₁ is used to discharge the energy of the inductor.

With reference to accompanying drawing 6, the present invention works in maintenance power-off mode. The dark path is the current flow path of each step sequence:

Figure 6(a), if the line needs to be repaired and powered off, the system will send a line maintenance command to the circuit breaker, and the circuit breaker will transfer the current to the transfer branch, and the transfer steps based on the fault clearing method are shown in Figure 4. ;

As shown in Figure 6(b), there is no need to limit the current afterwards, and the IGBT group T ₈ of the sub-section branch is directly turned off after the opening is completed, and the MOA is put into the breaking process.

The unexplained parts of the present invention are applicable to the prior art.

Claims (6)

1. A resistance-inductance current-limiting hybrid high-voltage DC circuit breaker topology, including: current-carrying branch, commutation branch, transfer branch, current-limiting branch, charging branch, breaking branch; Both ends of the current-carrying branch are respectively connected to the DC line interface, and at the same time, 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 reverse series; There are four groups of commutation branches in total. Each group of commutation branches is composed of thyristors and several diodes connected in series. The commutation branches on the opposite sides are directly connected, and at the same time, the end-to-end connections on each side are respectively connected to the corresponding interfaces of the DC line, and the entire commutation branch forms a bridge structure; The transfer branch is composed of several IGBT groups and thyristors connected in series, and connected inside the bridge structure of the commutation branch; The current-limiting branch is connected in parallel with the transfer branch and is composed of three parallel branches. The first branch is a branch consisting of a thyristor and a plurality of diodes connected in series and then an anti-parallel thyristor is connected in series with a capacitor. The second branch is an anti-parallel thyristor branch circuit, and the third branch is a branch circuit in which an inductance is connected in parallel with a resistance and then connected in series with the thyristor; The charging branch is composed of a capacitor connected in series with a thyristor connected to the upper end of the capacitor of the first current-limiting branch; The breaking branch is formed by parallel connection of IGBT group _T8 and metal oxide arrester MOA, connected in series to the current-limiting branch, and connected in series with the current-limiting branch at the same time and connected in parallel inside the bridge of the commutation branch. 2. The topology of resistance-inductive current-limiting hybrid HVDC circuit breaker according to claim 1, characterized in that there are four groups of commutation branches, Q ₁ , Q ₂ , Q ₃ , Q ₄ , each group The number of diodes connected in series in the commutation branch and the current limiting branch shall be determined according to the actual maximum voltage and current. 3. The resistance-inductive current-limiting hybrid HVDC circuit breaker topology according to claim ₁ , wherein the IGBT group T3 in the transfer branch is connected in series with the thyristor T2, and then connected to the breaking branch _IGBT group _T8 form a current path. 4. The topology of the resistance-inductive current-limiting hybrid high-voltage DC circuit breaker according to claim 1, wherein the charging branch is connected to the upper end of the capacitor _C1 of the first current-limiting branch, and then the capacitor _C2 and the capacitor C2 are connected in series. The thyristor T ₉ is grounded, and the pressure of the charging branch capacitor C ₂ is determined according to the pressure of the current-limiting branch capacitor C ₁ . 5. The topology of the resistance-inductance current-limiting hybrid high-voltage DC circuit breaker according to claim ₁ , wherein the inductance L1 and the resistance R1 in the third branch of the current _- limiting branch are connected in parallel with the thyristor _T7 in series , and the thyristor T ₆ of the second branch is anti-parallel connected on the third branch to form a bypass loop, and after the thyristor T ₄ of the first branch is naturally turned off, the thyristor T ₅ and the capacitor C ₁ are connected in series with the third branch The road constitutes an energy dissipation circuit. 6. The control method for the topology of the resistance-inductive current-limiting hybrid high-voltage DC circuit breaker according to any one of claims 1-5, wherein the circuit breaker works in the following three modes: If it is placed at the left end of the DC transmission line, that is, the current direction is to the right, firstly precharge the capacitor of the circuit breaker, turn on the commutation branch Q ₁ , the IGBT group T ₃ and the thyristor T ₂ in the transfer branch, and the charging branch The thyristor T ₉ in the circuit, after the charging is completed, the commutation branch Q ₁ and the thyristor T ₉ are naturally turned off; Fault clearing method: When an abnormal current is detected, a fault clearing command is sent to the circuit breaker, and the commutation branch Q ₁ and Q ₄ of the circuit breaker are turned on immediately, the thyristor T ₂ of the transfer branch, and the breaking branch IGBT group T ₈ , turn off the current-carrying branch, the current is quickly transferred from the current-carrying branch to the transfer branch, and at the same time quickly open the mechanical switch K ₁ , and complete the opening after reaching the rated opening distance; continue to conduct current limiting The thyristor T ₄ of the first branch of the branch, the capacitor C ₁ starts to discharge, the thyristor T ₂ is turned off after being subjected to back pressure, the current is transferred to the first branch of the current limiting branch, and the capacitor C ₁ starts to reverse charge, and in the positive The thyristor T7 is turned _on under the action of the voltage, and the current _- limiting inductance L1 and resistor R1 are input. At this time, because the charging current _of the capacitor _C1 gradually decreases until the thyristor T4 is naturally turned off, the current is gradually transferred to the first current _- limiting branch. Three branches; after the current limiting is fully put into use, if the system fault judgment is completed at this time, and the circuit breaker receives the fault clearing command, it will turn off the IGBT group T ₈ of the breaking branch and put it into MOA for breaking, and at the same time turn on the current limiting branch The second branch _T6 of the road bypasses the inductance and resistance. Due to the nonlinear characteristics of the MOA, the current decreases rapidly. When the current drops to zero, the MOA presents a high-impedance state, and the fault is cleared. Bypass the inductance and resistance energy, turn _on the thyristor T5 of the second branch _of the current _- limiting branch and put it into the capacitor _C1 . _The thyristor T5 of the first branch of the branch circuit and the third branch of the capacitor _C1 are connected in series to form an energy discharge circuit; Current limiting recovery mode: If the system judges that the fault is not needed to be cleared, and current recovery is required, the circuit breaker will turn on the thyristor T ₂ of the transfer branch and the thyristor T ₆ of the second branch of the current limiting branch after receiving the current limiting recovery command. Bypass the inductor and resistor of the current-limiting branch, and transfer the current from the third branch of the current-limiting branch to the transfer branch; then close the UFD, turn on the current-carrying branch after closing, and turn off the IGBT of the transfer branch Group T ₃ , at this time the current has completely recovered to the current-carrying branch, and then the thyristor T ₅ of the second branch of the current-limiting branch is turned on, and the capacitor C ₁ is used to discharge the energy of the inductor; Maintenance and power-off mode: If the line needs to be repaired and powered off, the system will send a line maintenance command to the circuit breaker. After the current is transferred to the transfer branch, the circuit breaker does not need to limit the current. IGBT group T ₈ is put into MOA for breaking process.

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