CN104767171B - A kind of high voltage DC breaker and its implementation - Google Patents

Abstract

The invention relates to a circuit breaker and its realization method, in particular to a high-voltage direct current circuit breaker and its realization method. The DC circuit breaker is based on the principle of secondary current transfer and includes a main branch connected in parallel, a current transfer branch and an energy absorption branch. The DC circuit breaker is connected in series in the DC system, and the main branch includes at least one A high-speed mechanical switch K and at least one current transfer module including fully controlled devices; the current transfer branch is a bridge circuit composed of thyristor valves, inductors, and capacitors; the energy absorption branch is composed of non-linear resistors, and a high-voltage DC circuit breaker is also provided The implementation method of the breaker, the circuit breaker circuit topology provided by the present invention is simple, the control is simple, and the power electronic device used is mainly a semi-controlled device thyristor, the technology is mature, easy to realize, the breaking current capacity is large, the withstand voltage level is high, and the expansion Strong ability, greatly reduce the cost.

Description

A high-voltage direct current circuit breaker and its realization method

technical field

The invention relates to a circuit breaker and its realization method, in particular to a high-voltage direct current circuit breaker and its realization method.

Background technique

With the application of multi-terminal flexible DC and DC grid technology based on voltage source converter (VSC), fast DC circuit breakers have become one of the key equipment to ensure the stable, safe and reliable operation of the system. In the AC system, the AC current has two natural zero-crossing points in one cycle, and the AC circuit breaker uses the natural zero-crossing points of the current to cut off the current, while in the DC system, the DC current does not have a natural zero-crossing point, so the DC current The breaking of the current is much more difficult than the breaking of the alternating current.

There are usually three ways to break the DC current. One is to add an auxiliary circuit on the basis of the conventional AC mechanical circuit breaker to superimpose the increased oscillation current on the DC current of the breaking arc gap, and use the current to break when the current crosses zero. The mechanical circuit breaker manufactured using this principle cannot meet the requirements of the multi-terminal flexible DC transmission system in terms of breaking time; one is to use high power to turn off power electronic devices and directly break the DC current, using this principle Although the manufactured solid-state circuit breaker can meet the requirements of the multi-terminal flexible DC system in terms of time, the loss is too large during normal conduction, and the economy is poor; the last one is a combination of mechanical switches and power electronic devices. In normal operation, the mechanical switch passes the current, and the mechanical switch is broken in case of failure. The generated arc voltage is used to transfer the current to the branch circuit of the power electronic device connected in parallel, and then the power electronic device breaks the current. Based on this principle, the circuit breaker not only reduces the on-state loss, but also increases the breaking speed, but it needs to use a large number of fully-controlled devices in series, which is difficult in technology and high in manufacturing costs. At its peak, its cost will nearly double.

Contents of the invention

In view of the deficiencies in the prior art, the object of the present invention is to provide a high-voltage DC circuit breaker, and another object is to provide a method for realizing a high-voltage DC circuit breaker. The circuit topology of the circuit breaker of the present invention is simple, easy to control, and can be used The current power electronic devices are mainly semi-controlled device thyristors, which are mature in technology, easy to implement, large in breaking current capacity, high in withstand voltage level, and strong in expansion ability, which greatly reduces the cost.

The object of the present invention is to adopt following technical scheme to realize:

The present invention provides a high-voltage DC circuit breaker. The DC circuit breaker is based on the principle of secondary current transfer and includes a parallel main branch, a current transfer branch and an energy absorption branch. The DC circuit breaker is connected in series in a DC system , the improvement is that the main branch includes at least one high-speed mechanical switch K connected in series and at least one current transfer module including a fully controlled device; the current transfer branch is a bridge current transfer branch; the energy The absorption branch is composed of non-linear resistors.

Further, the current transfer module adopts a full-bridge structure composed of four IGBT modules and a capacitor C1; each IGBT module is composed of an IGBT device and a freewheeling diode antiparallel to it.

Further, the current transfer module adopts a bridge circuit structure composed of four diodes, a parallel capacitor C2 and an IGBT module branch, and the IGBT module is composed of an IGBT device and a freewheeling diode antiparallel to it.

Further, the current transfer module is composed of IGBT modules connected in reverse series, and the capacitor C3 is connected in parallel at both ends of the IGBT module branches connected in reverse series; the IGBT module is composed of IGBT devices and freewheeling diodes connected in antiparallel with them composition.

Further, the bridge current transfer branch includes three sets of thyristor valve series branches and LC series branches connected in parallel; the first group of thyristor valve series branches is composed of thyristor valve T1 and thyristor valve T2 connected in series in the same direction;

The second group of thyristor valve series branch is composed of thyristor valve T5 and thyristor valve T6 connected in series in the same direction, the direction of the first group and the thyristor valve contained in the second group of thyristor valve branch are opposite, and the midpoint is connected; the first group and the second The midpoint connected to the group thyristor valve branch is connected to one end of the LC series branch;

The third group of thyristor valve series branches is composed of thyristor valve T3 and thyristor valve T4 connected in reverse series, and the midpoint of the two thyristor valves is connected to the other end of the LC series branch;

The LC series branch is composed of an inductor L and a capacitor C connected in series, and the capacitor C is precharged to a set value.

Further, the non-linear resistor is a lightning arrester.

The present invention provides a method for realizing a high-voltage DC circuit breaker based on another purpose. The improvement is that when the current transfer module adopts a full-bridge structure composed of four IGBT modules and capacitors, the method includes:

1) When the DC system is running normally, the high-speed mechanical switch K is closed, and the four IGBT devices in the current transfer module are in the triggered state; the steady-state current flows through the high-speed mechanical switch K and the current transfer module connected in series in the main branch, and the current is at The current transfer module is equally divided in two parallel-connected branches composed of IGBTs and freewheeling diodes in series; during the normal operation of the DC system, the capacitor C in the current transfer branch is charged to the set value;

2) One-sided short-circuit fault occurs in the DC system: ① When a ground short-circuit fault occurs in the DC system on the right side of the circuit breaker, a long trigger pulse is applied to the thyristor valves T1 and T2 in the current transfer branch, and then the current transfer module of the main branch is blocked Four IGBT devices in;

②The main branch current charges the capacitor C1 in the current transfer module through the freewheeling diodes D1 and D2. When the voltage across the capacitor C1 is higher than the minimum forward voltage required to trigger the thyristor valves T1 and T2, the thyristor valves T1 and T2 T2 will be normally opened, and the current flowing through the main branch will start to transfer to the thyristor valves T1 and T2 until it crosses zero, and then break the high-speed mechanical switch K;

③Keep the conduction of thyristor valves T1 and T2 for 2ms to ensure that the high-speed mechanical switch K produces an opening distance sufficient to withstand the overvoltage of the DC system; trigger the thyristor valve T3 in the current transfer branch, and the pre-charged capacitor C passes through the inductor L to the thyristor valve T1 Reverse injection current, the current is transferred from the thyristor valve T1 to the thyristor valve T3, and the thyristor valve T1 is turned off when the current drops to zero;

④The short-circuit current charges the capacitor C through the thyristor valve T3, capacitor C, inductor L and thyristor valve T2 until the polarity of the capacitor C is reversed. When its amplitude reaches the action threshold of the arrester, the arrester operates and the current is transferred to the arrester. The DC system energy will be consumed and absorbed, and the DC circuit breaker completes breaking.

Further, when the current transfer module adopts a bridge circuit structure composed of four diodes, parallel capacitors and IGBT module branches, the implementation method includes:

1) When the DC system is running normally, the high-speed mechanical switch K is closed, and the IGBT device in the current transfer module is in the triggered state; the steady-state current flows through the high-speed mechanical switch K and the current transfer module connected in series in the main branch circuit; in the normal DC system During operation, the capacitor C in the current transfer branch is charged to a set value;

2) One-sided short-circuit fault occurs in the DC system: ① When a ground short-circuit fault occurs in the DC system on the right side of the circuit breaker, a long trigger pulse is applied to the thyristor valves T1 and T2 in the current transfer branch, and then the current transfer module of the main branch is blocked IGBT devices in

②The main branch current charges the capacitor C1 in the current transfer module through the freewheeling diodes D1 and D2. When the voltage across the capacitor C1 is higher than the minimum forward voltage required to trigger the thyristor valves T1 and T2, the thyristor valves T1 and T2 T2 will be normally opened, and the current flowing through the main branch will start to transfer to the thyristor valves T1 and T2 until it crosses zero, and then break the high-speed mechanical switch K;

③Keep the conduction of thyristor valves T1 and T2 for 2ms to ensure that the high-speed mechanical switch K produces an opening distance sufficient to withstand the overvoltage of the DC system; trigger the thyristor valve T3 in the current transfer branch, and the pre-charged capacitor C passes through the inductor L to the thyristor valve T1 Reverse injection current, the current is transferred from the thyristor valve T1 to the thyristor valve T3, and the thyristor valve T1 is turned off when the current drops to zero;

④The short-circuit current charges the capacitor C through the thyristor valve T3, capacitor C, inductor L and thyristor valve T2 until the polarity of the capacitor C is reversed. When its amplitude reaches the action threshold of the arrester, the arrester operates and the current is transferred to the arrester. The DC system energy will be consumed and absorbed, and the DC circuit breaker completes breaking.

Further, when the current transfer module is composed of IGBT modules connected in reverse series, the implementation method includes:

1) When the DC system is running normally, the high-speed mechanical switch K is closed, and the two IGBT devices in the current transfer module are in the triggered state; the steady-state current flows through the high-speed mechanical switch K and the current transfer module connected in series in the main branch; in the DC During normal operation of the system, the capacitor C in the current transfer branch is charged to the set value;

2) One-sided short-circuit fault occurs in the DC system: ① When a ground short-circuit fault occurs in the DC system on the right side of the circuit breaker, a long trigger pulse is applied to the thyristor valves T1 and T2 in the current transfer branch, and then the current transfer module of the main branch is blocked Two IGBT devices in

②The main branch current charges the capacitor C1 in the current transfer module through the freewheeling diodes D1 and D2. When the voltage across the capacitor C1 is higher than the minimum forward voltage required to trigger the thyristor valves T1 and T2, the thyristor valves T1 and T2 T2 will be normally opened, and the current flowing through the main branch will start to transfer to the thyristor valves T1 and T2 until it crosses zero, and then break the high-speed mechanical switch K;

③Keep the conduction of thyristor valves T1 and T2 for 2ms to ensure that the high-speed mechanical switch K produces an opening distance sufficient to withstand the overvoltage of the DC system; trigger the thyristor valve T3 in the current transfer branch, and the pre-charged capacitor C passes through the inductor L to the thyristor valve T1 Reverse injection current, the current is transferred from the thyristor valve T1 to the thyristor valve T3, and the thyristor valve T1 is turned off when the current drops to zero;

④The short-circuit current charges the capacitor C through the thyristor valve T3, capacitor C, inductor L and thyristor valve T2 until the polarity of the capacitor C is reversed. When its amplitude reaches the action threshold of the arrester, the arrester operates and the current is transferred to the arrester. The DC system energy will be consumed and absorbed, and the DC circuit breaker completes breaking.

Compared with prior art, the beneficial effect that the present invention reaches is:

1. When the circuit breaker provided by the present invention is in normal operation, it is circulated by high-speed mechanical switches and a small amount of power electronic devices, and the on-state loss is small;

2. The circuit breaker provided by the present invention can realize arc-free breaking of mechanical switches, can prolong the service life of the switch, increase the breaking speed of the switch, and easily realize the voltage equalization problem when the switches are connected in series; the current transfer branch is composed of a thyristor valve, a capacitor , The inductance is composed of a bridge circuit, so that under the condition of single capacitor and unipolarity, the current can be transferred in both directions;

3. The circuit breaker topology provided by the present invention mainly uses semi-controlled power electronic devices, which are mature in technology, easy to implement, and greatly reduce manufacturing costs;

4. The capacitor used in the circuit breaker provided by the present invention only affects the reliable turn-off of the thyristor without affecting the performance of the switch. An energy absorption branch is installed at both ends of the circuit breaker in parallel to limit the overvoltage generated by breaking. Greatly reduce the size and cost of capacitors;

5. The thyristor used in the circuit breaker provided by the present invention has a strong current-through capacity, which greatly enhances its breaking current capacity, and does not require parallel connection of devices;

6. The thyristor used in the circuit breaker provided by the present invention has a higher withstand voltage capability, and when it is applied to a high voltage level, it has more advantages in technology and economy;

7. The circuit breaker provided by the present invention is novel in structure, simple in control, quick in action, high in withstand voltage level, and easy to expand to DC grids of different voltage levels, including traditional UHV DC grids.

Description of drawings

Fig. 1 is the topological structure diagram of the high-voltage DC circuit breaker provided by the present invention;

Fig. 2 is Embodiment 1 of the current transfer module provided by the present invention;

Fig. 3 is the second embodiment of the current transfer module provided by the present invention;

Fig. 4 is the third embodiment of the current transfer module provided by the present invention;

Fig. 5 is a schematic breaking diagram of the circuit breaker in Embodiment 1 using the current transfer module provided by the present invention.

detailed description

The specific implementation manners of the present invention will be further described in detail below in conjunction with the accompanying drawings.

The topological structure diagram of the high-voltage DC circuit breaker provided by the present invention is shown in Figure 1. The high-voltage DC circuit breaker is connected in series to the DC system through ports 1 and 2, and includes three parts, one part is composed of at least one high-speed mechanical switch and at least one current The main branch formed by the transfer module, a bridge current transfer branch composed of thyristor valves, inductors and capacitors, and an energy absorbing branch composed of non-linear resistors.

The current transfer module adopts a full-bridge structure composed of four IGBT modules and capacitor C1; each IGBT module is composed of an IGBT device and a freewheeling diode connected in antiparallel to it, as shown in Figure 2; four diodes, A bridge circuit structure composed of a capacitor C2 connected in parallel and an IGBT module branch. The IGBT module is composed of an IGBT device and a freewheeling diode connected in antiparallel to it, as shown in Figure 3; or it is composed of an IGBT module connected in reverse series , the capacitor C3 is connected in parallel at both ends of the IGBT module branch connected in reverse series; the IGBT module is composed of an IGBT device and a freewheeling diode connected in antiparallel with it, as shown in FIG. 4 .

The bridge current transfer branch includes three sets of thyristor valve series branches and LC series branches connected in parallel; the first group of thyristor valve series branches is composed of thyristor valve T1 and thyristor valve T2 connected in series in the same direction; the second group of thyristor valves is connected in series The branch is composed of thyristor valve T5 and thyristor valve T6 connected in series in the same direction; the direction of the thyristor valve contained in the first group and the second group of thyristor valve branch is opposite, and the midpoint is connected; the first group and the second group of thyristor valve branch are connected The connection midpoint is connected to one end of the LC series branch; the third group of thyristor valve series branches is composed of thyristor valve T3 and thyristor valve T4 connected in reverse series, and the midpoint of the two thyristor valves is connected to the other end of the LC series branch; The LC series branch is composed of an inductance L and a capacitor C connected in series, and the capacitor C is precharged to a set value by a charging power supply.

The present invention also provides a method for realizing a high-voltage DC circuit breaker, including:

The working principle of the boosted voltage DC circuit breaker is described by using the embodiment of the current transfer module shown in FIG. 2 , as shown in FIG. 5 .

1) When the DC system is running normally, the high-speed switch K is closed, and the four IGBT devices in the current transfer module are in the triggered state, and the steady-state current flows through the high-speed mechanical switch K and the current transfer module connected in series in the main branch, and the steady-state current In the current transfer module, it is equally divided in the series branch composed of two parallel connected IGBTs and freewheeling diodes. If the current transfer module can withstand the on-state voltage drop higher than that of the first current transfer branch, so that the thyristor is successfully turned on without being damaged, that is, the current can be transferred smoothly, so the withstand voltage required by it is very low , one module unit can meet the requirements of normal operation, reducing the number of power electronic devices used in the main branch circuit, so that the loss generated during normal operation of the circuit breaker is very small. During normal operation of the system, the capacitor in the second current transfer branch is precharged through the auxiliary power system.

2) Taking the single-sided short-circuit fault as an example, explain the working principle of the circuit breaker in the event of a fault. When the ground fault occurs on the right side of the system, first isolate the power supply from the capacitor, then apply a long trigger pulse to the thyristor valves T1 and T2 in the bridge circuit, and then block the four IGBT devices in the main branch current transfer module. At this time, the main branch current charges the capacitor through the freewheeling diodes D1 and D2. Since the initial voltage is too low, the thyristor receives the trigger pulse, but it still cannot be turned on. When the voltage across the capacitor is higher than the trigger valve T1 and T2 When the minimum forward voltage is required, the valves T1 and T2 will be normally opened, and the current flowing through the main branch will start to transfer to the valves T1 and T2 until it crosses zero, and then the fast mechanical switch will be broken. Keep the valves T1 and T2 conducting for 2ms, so that the high-speed mechanical switch can generate an opening distance sufficient to withstand the overvoltage of the system. At this time, the thyristor valve T3 in the bridge circuit is triggered, and the pre-charged capacitor injects a reverse current into the valve T1 through the inductance, and the current is transferred from the valve T1 to the valve T3. When the current of T1 drops to zero, it is turned off. By designing appropriate parameters, Ensure that valve T1 can be shut off reliably. The short-circuit current charges the capacitor C through the thyristor valve T3, capacitor C, inductor L and thyristor valve T2 until the polarity of the capacitor C is reversed. When the amplitude of the capacitor C reaches the action threshold of the arrester, the arrester operates and the current is transferred to the arrester. The system energy will be consumed and absorbed, and the DC circuit breaker completes breaking.

When the current transfer module adopts a bridge circuit structure composed of four diodes, parallel capacitors and IGBT module branches as shown in Figure 3, the implementation method includes:

1) When the DC system is running normally, the high-speed mechanical switch K is closed, and the IGBT device in the current transfer module is in the trigger state; the steady-state current flows through the high-speed mechanical switch K and the current transfer module connected in series in the main branch circuit; During operation, the capacitor C in the current transfer branch is charged to a set value;

2) One-sided short-circuit fault occurs in the DC system: ① When a ground short-circuit fault occurs in the DC system on the right side of the circuit breaker, a long trigger pulse is applied to the thyristor valves T1 and T2 in the current transfer branch, and then the current transfer module of the main branch is blocked IGBT devices in

②The main branch current charges the capacitor C1 in the current transfer module through the freewheeling diodes D1 and D2. When the voltage across the capacitor C1 is higher than the minimum forward voltage required to trigger the thyristor valves T1 and T2, the thyristor valves T1 and T2 T2 will be normally opened, and the current flowing through the main branch will start to transfer to the thyristor valves T1 and T2 until it crosses zero, and then break the high-speed mechanical switch K;

③Keep the conduction of thyristor valves T1 and T2 for 2ms to ensure that the high-speed mechanical switch K produces an opening distance sufficient to withstand the overvoltage of the DC system; trigger the thyristor valve T3 in the current transfer branch, and the pre-charged capacitor C passes through the inductor L to the thyristor valve T1 Reverse injection current, the current is transferred from the thyristor valve T1 to the thyristor valve T3, and the thyristor valve T1 is turned off when the current drops to zero;

④The short-circuit current charges the capacitor C through the thyristor valve T3, capacitor C, inductor L and thyristor valve T2 until the polarity of the capacitor C is reversed. When its amplitude reaches the action threshold of the arrester, the arrester operates and the current is transferred to the arrester. The DC system energy will be consumed and absorbed, and the DC circuit breaker completes breaking.

When the current transfer module is composed of IGBT modules connected in reverse series as shown in Figure 4, the implementation method includes:

1) When the DC system is running normally, the high-speed mechanical switch K is closed, and the two IGBT devices in the current transfer module are in the triggered state; the steady-state current flows through the high-speed mechanical switch K and the current transfer module connected in series in the main branch; in the DC During normal operation of the system, the capacitor C in the current transfer branch is charged to the set value;

2) One-sided short-circuit fault occurs in the DC system: ① When a ground short-circuit fault occurs in the DC system on the right side of the circuit breaker, a long trigger pulse is applied to the thyristor valves T1 and T2 in the current transfer branch, and then the current transfer module of the main branch is blocked Two IGBT devices in

②The main branch current charges the capacitor C1 in the current transfer module through the freewheeling diodes D1 and D2. When the voltage across the capacitor C1 is higher than the minimum forward voltage required to trigger the thyristor valves T1 and T2, the thyristor valves T1 and T2 T2 will be normally opened, and the current flowing through the main branch will start to transfer to the thyristor valves T1 and T2 until it crosses zero, and then break the high-speed mechanical switch K;

③Keep the conduction of thyristor valves T1 and T2 for 2ms to ensure that the high-speed mechanical switch K produces an opening distance sufficient to withstand the overvoltage of the DC system; trigger the thyristor valve T3 in the current transfer branch, and the pre-charged capacitor C passes through the inductor L to the thyristor valve T1 Reverse injection current, the current is transferred from the thyristor valve T1 to the thyristor valve T3, and the thyristor valve T1 is turned off when the current drops to zero;

④The short-circuit current charges the capacitor C through the thyristor valve T3, capacitor C, inductor L and thyristor valve T2 until the polarity of the capacitor C is reversed. When its amplitude reaches the action threshold of the arrester, the arrester operates and the current is transferred to the arrester. The DC system energy will be consumed and absorbed, and the DC circuit breaker completes breaking.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: the present invention can still be Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention shall be covered by the scope of the claims of the present invention.

Claims (3)

1. A method for realizing a high-voltage direct current circuit breaker, characterized in that, the high-voltage direct current circuit breaker is based on the principle of secondary current transfer, including a parallel main branch, a current transfer branch and an energy absorption branch, and the direct current circuit breaker The switch is connected in series in the DC system, and it is characterized in that the main branch includes at least one high-speed mechanical switch K and at least one current transfer module including a fully controlled device connected in series; the current transfer branch is a bridge current transfer branch Road; the energy absorption branch is formed by a non-linear resistor; The current transfer module adopts a full-bridge structure composed of four IGBT modules and a capacitor C1; each IGBT module is composed of an IGBT device and a freewheeling diode antiparallel to it; The bridge-type current transfer branch includes three sets of thyristor valve series branches and LC series branches connected in parallel; the first group of thyristor valve series branches is composed of thyristor valve T1 and thyristor valve T2 connected in series in the same direction; The second group of thyristor valve series branch is composed of thyristor valve T5 and thyristor valve T6 connected in series in the same direction, the direction of the first group and the thyristor valve contained in the second group of thyristor valve branch are opposite, and the midpoint is connected; the first group and the second The midpoint connected to the group thyristor valve branch is connected to one end of the LC series branch; The third group of thyristor valve series branches is composed of thyristor valve T3 and thyristor valve T4 connected in reverse series, and the midpoint of the two groups of thyristor valves is connected to the other end of the LC series branch; The LC series branch is composed of an inductance L and a capacitor C connected in series, and the capacitor C is precharged to a set value; The non-linear resistor is a lightning arrester; When the current transfer module adopts a full bridge structure composed of four IGBT modules and capacitors, the implementation method includes: 1) When the DC system is running normally, the high-speed mechanical switch K is closed, and the four IGBT devices in the current transfer module are in the triggered state; the steady-state current flows through the high-speed mechanical switch K and the current transfer module connected in series in the main branch, and the current is at The current transfer module is equally divided in two parallel-connected branches composed of IGBTs and freewheeling diodes in series; during the normal operation of the DC system, the capacitor C in the current transfer branch is charged to the set value; 2) One-sided short-circuit fault occurs in the DC system: ① When a ground short-circuit fault occurs in the DC system on the right side of the circuit breaker, a long trigger pulse is applied to the thyristor valves T1 and T2 in the current transfer branch, and then the current transfer module of the main branch is blocked Four IGBT devices in; ②The main branch current charges the capacitor C1 in the current transfer module through the freewheeling diodes D1 and D2. When the voltage across the capacitor C1 is higher than the minimum forward voltage required to trigger the thyristor valves T1 and T2, the thyristor valves T1 and T2 T2 will be normally opened, and the current flowing through the main branch will start to transfer to the thyristor valves T1 and T2 until it crosses zero, and then break the high-speed mechanical switch K; ③Keep the conduction of thyristor valves T1 and T2 for 2ms to ensure that the high-speed mechanical switch K produces an opening distance sufficient to withstand the overvoltage of the DC system; trigger the thyristor valve T3 in the current transfer branch, and the pre-charged capacitor C passes through the inductor L to the thyristor valve T1 Reverse injection current, the current is transferred from the thyristor valve T1 to the thyristor valve T3, and the thyristor valve T1 is turned off when the current drops to zero; ④The short-circuit current charges the capacitor C through the thyristor valve T3, capacitor C, inductor L and thyristor valve T2 until the polarity of the capacitor C is reversed. When its amplitude reaches the action threshold of the arrester, the arrester operates and the current is transferred to the arrester. The DC system energy will be consumed and absorbed, and the DC circuit breaker completes breaking. 2. A method for realizing a high-voltage direct current circuit breaker, characterized in that the high-voltage direct current circuit breaker is based on the principle of secondary current transfer, including a parallel main branch, a current transfer branch and an energy absorption branch, and the direct current circuit breaker The switch is connected in series in the DC system, and it is characterized in that the main branch includes at least one high-speed mechanical switch K and at least one current transfer module including a fully controlled device connected in series; the current transfer branch is a bridge current transfer branch Road; the energy absorption branch is formed by a non-linear resistor; The current transfer module adopts a bridge circuit structure composed of four diodes, a parallel capacitor C2 and an IGBT module branch, and the IGBT module is composed of an IGBT device and a freewheeling diode antiparallel to it; The bridge-type current transfer branch includes three sets of thyristor valve series branches and LC series branches connected in parallel; the first group of thyristor valve series branches is composed of thyristor valve T1 and thyristor valve T2 connected in series in the same direction; The second group of thyristor valve series branch is composed of thyristor valve T5 and thyristor valve T6 connected in series in the same direction, the direction of the first group and the thyristor valve contained in the second group of thyristor valve branch are opposite, and the midpoint is connected; the first group and the second The midpoint connected to the group thyristor valve branch is connected to one end of the LC series branch; The third group of thyristor valve series branches is composed of thyristor valve T3 and thyristor valve T4 connected in reverse series, and the midpoint of the two groups of thyristor valves is connected to the other end of the LC series branch; The LC series branch is composed of an inductance L and a capacitor C connected in series, and the capacitor C is precharged to a set value; The non-linear resistor is a lightning arrester; When the current transfer module adopts a bridge circuit structure composed of four diodes, parallel capacitors and IGBT module branches, the implementation method includes: 1) When the DC system is running normally, the high-speed mechanical switch K is closed, and the IGBT device in the current transfer module is in the triggered state; the steady-state current flows through the high-speed mechanical switch K and the current transfer module connected in series in the main branch circuit; in the normal DC system During operation, the capacitor C in the current transfer branch is charged to a set value; 2) One-sided short-circuit fault occurs in the DC system: ① When a ground short-circuit fault occurs in the DC system on the right side of the circuit breaker, a long trigger pulse is applied to the thyristor valves T1 and T2 in the current transfer branch, and then the current transfer module of the main branch is blocked IGBT devices in ②The main branch current charges the capacitor C1 in the current transfer module through the freewheeling diodes D1 and D2. When the voltage across the capacitor C1 is higher than the minimum forward voltage required to trigger the thyristor valves T1 and T2, the thyristor valves T1 and T2 T2 will be normally opened, and the current flowing through the main branch will start to transfer to the thyristor valves T1 and T2 until it crosses zero, and then break the high-speed mechanical switch K; ③Keep the conduction of thyristor valves T1 and T2 for 2ms to ensure that the high-speed mechanical switch K produces an opening distance sufficient to withstand the overvoltage of the DC system; trigger the thyristor valve T3 in the current transfer branch, and the pre-charged capacitor C passes through the inductor L to the thyristor valve T1 Reverse injection current, the current is transferred from the thyristor valve T1 to the thyristor valve T3, and the thyristor valve T1 is turned off when the current drops to zero; ④The short-circuit current charges the capacitor C through the thyristor valve T3, capacitor C, inductor L and thyristor valve T2 until the polarity of the capacitor C is reversed. When its amplitude reaches the action threshold of the arrester, the arrester operates and the current is transferred to the arrester. The DC system energy will be consumed and absorbed, and the DC circuit breaker completes breaking. 3. A method for realizing a high-voltage direct current circuit breaker, characterized in that the high-voltage direct current circuit breaker is based on the principle of secondary current transfer, including a parallel main branch, a current transfer branch and an energy absorption branch, and the direct current circuit breaker The switch is connected in series in the DC system, and it is characterized in that the main branch includes at least one high-speed mechanical switch K and at least one current transfer module including a fully controlled device connected in series; the current transfer branch is a bridge current transfer branch Road; the energy absorption branch is formed by a non-linear resistor; The current transfer module is composed of IGBT modules connected in reverse series, and the capacitor C3 is connected in parallel at both ends of the branch circuit of the IGBT modules connected in reverse series; the IGBT module is composed of IGBT devices and freewheeling diodes connected in antiparallel with them; The bridge-type current transfer branch includes three sets of thyristor valve series branches and LC series branches connected in parallel; the first group of thyristor valve series branches is composed of thyristor valve T1 and thyristor valve T2 connected in series in the same direction; The second group of thyristor valve series branch is composed of thyristor valve T5 and thyristor valve T6 connected in series in the same direction, the direction of the first group and the thyristor valve contained in the second group of thyristor valve branch are opposite, and the midpoint is connected; the first group and the second The midpoint connected to the group thyristor valve branch is connected to one end of the LC series branch; The third group of thyristor valve series branches is composed of thyristor valve T3 and thyristor valve T4 connected in reverse series, and the midpoint of the two groups of thyristor valves is connected to the other end of the LC series branch; The LC series branch is composed of an inductance L and a capacitor C connected in series, and the capacitor C is precharged to a set value; The non-linear resistor is a lightning arrester; When the current transfer module is composed of IGBT modules connected in reverse series, the implementation method includes: 1) When the DC system is operating normally, the high-speed mechanical switch K is closed, and the two IGBT devices in the current transfer module are in the triggered state; the steady-state current flows through the high-speed mechanical switch K and the current transfer module connected in series in the main branch; in the DC During normal operation of the system, the capacitor C in the current transfer branch is charged to the set value; 2) One-sided short-circuit fault occurs in the DC system: ① When a ground short-circuit fault occurs in the DC system on the right side of the circuit breaker, a long trigger pulse is applied to the thyristor valves T1 and T2 in the current transfer branch, and then the current transfer module of the main branch is blocked Two IGBT devices in ②The main branch current charges the capacitor C1 in the current transfer module through the freewheeling diodes D1 and D2. When the voltage across the capacitor C1 is higher than the minimum forward voltage required to trigger the thyristor valves T1 and T2, the thyristor valves T1 and T2 T2 will be normally opened, and the current flowing through the main branch will start to transfer to the thyristor valves T1 and T2 until it crosses zero, and then break the high-speed mechanical switch K; ③Keep the conduction of thyristor valves T1 and T2 for 2ms to ensure that the high-speed mechanical switch K produces an opening distance sufficient to withstand the overvoltage of the DC system; trigger the thyristor valve T3 in the current transfer branch, and the pre-charged capacitor C passes through the inductor L to the thyristor valve T1 Reverse injection current, the current is transferred from the thyristor valve T1 to the thyristor valve T3, and the thyristor valve T1 is turned off when the current drops to zero; ④The short-circuit current charges the capacitor C through the thyristor valve T3, capacitor C, inductor L and thyristor valve T2 until the polarity of the capacitor C is reversed. When its amplitude reaches the action threshold of the arrester, the arrester operates and the current is transferred to the arrester. The DC system energy will be consumed and absorbed, and the DC circuit breaker completes breaking.