CN103646805B - A kind of direct-current breaker topology - Google Patents

Abstract

A DC circuit breaker topology, consisting of a first current path (1), a second current path (2), a third current path (3) and a fourth path (4). The first lead-out terminal of the fourth current path (4), the first lead-out terminal of the third current path (3), the first lead-out terminal of the second current path (2) and the first lead-out terminal of the first current path (1) The terminals are connected together, as the first lead-out terminal (5) of the DC circuit breaker is connected to one end of the DC transmission line; the second lead-out terminal of the fourth current path (4), the second lead-out terminal of the third current path (3) , the second lead-out terminal of the second current path (2) is connected with the second lead-out terminal of the first current path (1), as the second lead-out terminal (6) of the DC circuit breaker is connected to the other end of the DC transmission line . When the system is running normally, the loss of the DC circuit breaker is small, and when the high-voltage DC transmission line fails, it can quickly break the faulty transmission line.

Description

A DC Circuit Breaker Topology

technical field

The invention relates to a circuit breaker, in particular to a DC circuit breaker.

Background technique

Fast DC circuit breaker is one of the key equipment to ensure the stable, safe and reliable operation of DC power transmission and distribution system and DC grid system. Different from the AC system, the current of the DC system does not have a natural zero-crossing point, so the natural zero-crossing point of the current cannot be used in the DC system like the AC system. Therefore, the breaking of the DC current has always been a problem worth studying. topic.

At present, there are usually two ways to break the DC current. The first is a pure power electronic circuit breaker, such as the patent CN102870181A applied by ABB, which can turn off the power electronic device by using high power and directly break the DC current. Although the solid-state circuit breaker manufactured by this principle 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 second is the hybrid circuit breaker technology, that is, on the basis of the traditional AC mechanical circuit breaker, by adding an auxiliary power electronic circuit, inputting a current limiting resistor to reduce the short-circuit current or superimposing an oscillating current on the DC current that opens the arc gap , use the current to break the circuit when it crosses zero. The hybrid circuit breaker manufactured using this principle has special requirements for mechanical switches, and it is difficult to meet the requirements of the DC transmission system in terms of breaking time.

Siemens patent WO2013/093066A1 proposes a hybrid circuit breaker. A mechanical switch and a power electronic full control device are connected in series on the main path, and the other bypass is composed of a capacitor. When a fault current is detected, the power electronic full control device on the main path is broken. Open, the mechanical switch also starts to break, and the fault current charges the bypass capacitor. The value of the bypass capacitor of this circuit should not be too small, otherwise the mechanical switch has not been fully opened. If the voltage of the bypass capacitor rises too fast under the fault current charging It will exceed the withstand voltage level of mechanical switches and power electronic devices. However, when the capacitance value is large, the breaking speed will be affected.

ABB’s patent WO2011141054A1 proposes a hybrid circuit breaker, in which a mechanical switch and a power electronic full-control device are connected in series on the main path, and the other bypass is composed of a surge arrester and a crimped IGBT connected in parallel. When a fault current is detected, the voltage on the bypass The IGBTs are all turned on, and then the power electronic full-control devices on the main path are disconnected, and the mechanical switch is also turned off. After the mechanical switch is completely turned off, the crimping IGBT is turned off, and the arrester is connected to the circuit to suppress the short-circuit current. The breaking speed of the circuit breaker is fast, but the sum of the withstand voltage of the crimped IGBTs of the entire bypass must be greater than the initial voltage of the DC transmission line, which requires a large number of crimped IGBTs to be connected in series, resulting in a high cost of the entire DC circuit breaker.

Moreover, the main circuits of the above two patents must use full-control switching devices connected in series with mechanical switches, resulting in relatively large conduction losses in normal conditions.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies of the prior art and propose a hybrid DC circuit breaker. The invention has the characteristics of low overall cost, low loss during steady-state operation, no arc cut-off when a short-circuit fault occurs, and rapid response.

The DC circuit breaker of the present invention is composed of a first current path, a second current path, a third current path and a fourth current path. The first lead-out terminal of the fourth current path, the first lead-out terminal of the third current path, the first lead-out terminal of the second current path, and the first lead-out terminal of the first current path are connected together as the first lead-out terminal of the DC circuit breaker. The lead-out terminal is connected to one end of the DC transmission line; the second lead-out terminal of the fourth current path, the second lead-out terminal of the third current path, the second lead-out terminal of the second current path, and the second lead-out terminal of the first current path are connected to Together, as the second lead-out terminal of the DC circuit breaker, it is connected to the other end of the DC transmission line.

Another connection mode of the DC circuit breaker is: the first lead-out terminal of the fourth current path, the first lead-out terminal of the third current path, the first lead-out terminal of the second current path, the first lead-out terminal of the first current path After the lead-out terminals are connected together, they can be connected to one end of the inductance, and the other end of the inductance is used as the first lead-out terminal of the DC circuit breaker to connect to the DC transmission line.

The second lead-out terminal of the fourth current path, the second lead-out terminal of the third current path, the second lead-out terminal of the second current path, and the second lead-out terminal of the first current path can also be connected to one end of the inductor after they are connected together. The other end of the DC circuit breaker is connected to the other end of the DC transmission line as the second lead-out terminal of the DC circuit breaker.

The first current path is composed of a power electronic switch module and a mechanical switch module. One end of the power electronic switch module is connected to one end of the mechanical switch, and the other end of the power electronic switch module is used as a first lead-out terminal of the first current path.

The second current path includes a half-controlled device module and a full-controlled device module, the anode of the half-controlled device module is used as the first lead-out terminal of the second current path, and the cathode of the half-controlled device module One end of the module is connected; the other end of the full-control device module is used as the second lead-out terminal of the second current path.

The third current path is composed of a capacitor module, and the capacitor module is composed of at least one capacitor unit connected in series or in parallel.

The fourth current path is composed of a voltage limiting device module, and the voltage limiting device module is composed of at least one voltage limiting device connected in series.

When the DC transmission line is in normal operation, the mechanical switch module of the first current path is in the closed state, and the power electronic switch module of the first current path is in the conductive state; when a line short circuit fault is detected, the The semi-controlled device module and the full-controlled device module of the second current path receive the conduction signal, and at the same time, the power electronic switch module of the first current path is quickly turned off, blocking the fault current of the first current path, and the mechanical The switch module starts to break, and the fault current is quickly transferred to the second current path; when the contacts at both ends of the mechanical switch module of the first current path are broken to a certain distance, the full-control device module of the second current path is quickly turned off, blocking Cut off the fault current flowing through the second current path, the current of the semi-controlled device module in the second current path crosses zero and shut down naturally, the fault current is transferred to the third current path, and the capacitor module in the third current path is charged, when the third When the voltage across the capacitor module of the current path rises to the limit value of the fourth current path voltage limiting device module, the current switches from the third current path to the fourth current path. A high value causes the fault current to drop rapidly to zero.

A voltage limiting device may be connected in parallel between the first lead-out terminal of the DC circuit breaker and the ground, and a voltage limiting device may be connected in parallel between the second lead-out terminal of the DC circuit breaker and the ground.

The number of series half-controlled devices in the half-controlled device module of the second current path and the number of fully-controlled devices in the full-controlled device module in the second current path can be flexibly coordinated and configured, and the half-controlled device in the second current path Voltage limiting devices with different limits are connected in parallel at both ends of the device module and the second current path full-control device module, so that the voltage is borne by the half-control device module as much as possible. It is also possible to connect voltage limiting devices in parallel at both ends of various device modules that need protection.

The second current path semi-controlled device module is composed of at least one semi-controlled device in series, and the full-controlled device module is composed of at least one fully-controlled device connected in series. This configuration method can make the DC circuit breaker have unidirectional current blocking ability.

The second current path half-controlled device module is composed of at least one anti-parallel half-controlled device unit in series, and the second current path full-control device module is composed of the first group of full-control devices and the second group of full-control devices type devices in reverse series; at the same time, the first current path fully-controlled device module is also composed of the first group of fully-controlled devices and the second group of fully-controlled devices, and each group consists of at least one fully-controlled device in the same direction Composed in series. This configuration method can make the entire DC circuit breaker have bidirectional current blocking capability.

The DC circuit breaker may also only include the second current path, the third current path and the fourth current path, omitting the first current path, so that the breaking speed is faster, but the conduction loss is higher.

The first current path of the DC circuit breaker may only include a mechanical switch module, and the power electronic switch of the first current path may be replaced by wires.

The second current path of the DC circuit breaker may only include full-control device modules.

A blocking power electronic switch module composed of full-control devices is added between the first lead-out terminal of the first current path of the DC circuit breaker and the first lead-out terminal of the second current path.

The blocking power electronic module is composed of a semi-controlled device series module and a full-controlled device series module connected in series.

A discharge device can be added at both ends of the third current path capacitor module, so that after the DC line short circuit fault is eliminated, the excess voltage in the capacitor can be quickly discharged to facilitate re-closing.

The present invention has the following advantages:

a. The topological breaking of the DC circuit breaker is faster and can achieve zero arc breaking;

b. The entire commutation topology can use conventional components, which is relatively less difficult to manufacture and has high reliability;

c. The DC circuit breaker can control the short-circuit current at a lower level, thereby protecting the safety of the system;

d. The DC circuit breaker topology can reduce the impact of short-circuit current on the converter station;

e. It is easier to combine with the flexible DC transmission system and is suitable for integrated design;

f. Compared with the pure power electronic switching DC circuit breaker, the loss of the system during normal operation is smaller;

g. When a half-controlled device is used to replace the fully-controlled power electronic switch on the initial current path, the normal operating loss of the system can be reduced to a lower level;

h. The current blocking path of the circuit breaker adopts the multi-current path switching design method, and the cost of the overall implementation scheme is lower while the breaking speed is fast;

i. Possibility of multi-degree-of-freedom optimization design, the fourth current path and the third current path have different cost configuration methods, and can be flexibly configured according to the breaking speed requirements of the actual working conditions.

Description of drawings

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

Fig. 1 is a schematic circuit diagram of the present invention;

Fig. 2 is the schematic circuit diagram of the specific embodiment 1 of the present invention;

Fig. 3 is the schematic circuit diagram of the specific embodiment 2 of the present invention;

Fig. 4 is the schematic circuit diagram of the specific embodiment 3 of the present invention;

Fig. 5 is the schematic circuit diagram of the specific embodiment 4 of the present invention;

FIG. 6 is a schematic circuit diagram of Embodiment 5 of the present invention.

detailed description

As shown in Figure 1, the DC circuit breaker of the present invention includes a first current path 1, a second current path 2, a third current path 3 and a fourth current path 4; the first lead-out terminal of the fourth current path 4, the third current path The first lead-out terminal of the path 3, the first lead-out terminal of the second current path and the first lead-out terminal of the first current path are connected together, as the first lead-out terminal 5 of the DC circuit breaker is connected to one end of the DC transmission line; The second lead-out terminal of the four current path 4, the second lead-out terminal of the third current path 3, the second lead-out terminal of the second current path 2 and the second lead-out terminal of the first current path are connected together as the first lead-out terminal of the DC circuit breaker The second lead-out terminal 6 is connected to the other end of the DC transmission line.

The first current path 1 is composed of a power electronic switch module 12 and a mechanical switch module 11 . One end of the power electronic switch module is connected to one end 13 of the mechanical switch, and the other end of the power electronic switch module is used as a first lead-out terminal of the first current path.

The second current path 2 includes a half-controlled device module 21 and a full-controlled device module 22, the anode of the half-controlled device module 21 is used as the first lead-out terminal of the second current path 2, and the half-controlled device module 22 The cathode is connected to one end 23 of the full-control device module 22 ; the other end of the full-control device module is used as the second lead-out terminal of the second current path 2 .

The third current path 3 is composed of a capacitor module C1, and the capacitor module is composed of at least one capacitor unit connected in series or in parallel.

The fourth current path 4 is composed of a voltage limiting device module, and the voltage limiting device module is composed of at least one voltage limiting device connected in series.

Example 1

Figure 2 shows Embodiment 1 of the present invention. As shown in FIG. 2 , the voltage source 15 is a converter station, and the resistor 16 is a simulated short-circuit resistor. The DC circuit breaker of the present invention is composed of a first current path 1, a second current path 2, a third current path 3 and a fourth current path 4; Lead-out terminals, the first lead-out terminal of the second current path and the first lead-out terminal of the first current path are connected together, as the first lead-out terminal 5 of the DC circuit breaker is connected with one end of the DC transmission line; the fourth current path 4 The second lead-out terminal, the second lead-out terminal of the third current path 3, the second lead-out terminal of the second current path 2 and the second lead-out terminal of the first current path are connected together, as the second lead-out terminal 6 of the DC circuit breaker and Connect the other end of the DC power line.

The first current path 1 is composed of a power electronic switch module 12 and a mechanical switch module 11 . One end of the power electronic switch module is connected to one end of the mechanical switch, and the other end of the power electronic switch module is used as a first lead-out terminal of the first current path.

The second current path 2 includes a half-controlled device module 21 and a full-controlled device module 22, the anode of the half-controlled device module 21 is used as the first lead-out terminal of the second current path 2, and the half-controlled device module 22 The cathode is connected to one end 23 of the full-control device module 22 ; the other end of the full-control device module is used as the second lead-out terminal of the second current path 2 .

The third current path 3 is composed of a capacitor module C1, and the capacitor module is composed of at least one capacitor unit connected in series or in parallel.

The fourth current path 4 is composed of a voltage limiting device module, and the voltage limiting device module is composed of at least one voltage limiting device connected in series.

When the DC transmission line is in normal operation, the mechanical switch module 11 of the first current path 1 is in the closed state, and the power electronic switch module 12 of the first current path 1 is in the conductive state; when a line short circuit fault is detected, the second The semi-controlled device module 21 of the second current path 2 and the full-controlled device module 22 of the second current path 2 receive the conduction signal, and the power electronic switch module 12 of the first current path 1 is quickly turned off, blocking Break the fault current of the first current path 1, the mechanical switch module 11 starts to break, and the fault current is quickly transferred to the second current path 2; when the contacts at both ends of the mechanical switch module 11 of the first current path 1 are broken to a certain distance Finally, the fully-controlled device module 22 of the second current path 2 is quickly turned off, blocking the fault current flowing through the second current path 2, and the half-controlled device module 21 of the second current path 2 is naturally turned off when the current crosses zero. The fault current is transferred to the third current path 3 to charge the capacitor module C1 of the third current path 3, when the voltage across the capacitor module C1 of the third current path 3 rises to the limit value of the voltage limiting device module of the fourth current path 4 , the current is switched from the third current path 3 to the fourth current path 4. At this time, because the voltage across the capacitor module C1 is at a value higher than that of the DC transmission substation, the fault current drops rapidly to zero.

Between the first lead-out terminal of the first current path 1 and the ground, and between the second lead-out terminal of the first current path 1 and the ground, for overvoltage protection of various parts of the entire DC circuit breaker. It is also possible to selectively add voltage limiting devices at both ends of the place where protection is required.

Example 2

Figure 3 shows Embodiment 2 of the present invention. As shown in FIG. 3 , the half-controlled device module 21 of the second current path 2 is composed of at least one anti-parallel half-controlled device unit 24 connected in series. The fully-controlled device module 22 of the second current path 2 is composed of the first group of fully-controlled devices 25 of the second current path and the second group of fully-controlled devices 26 of the second current path in reverse series. Both the controlled device 25 and the second group of fully controlled devices 26 are composed of at least one fully controlled device connected in series in the same direction. The fully-controlled device module of the first current path 1 is composed of a first group of fully-controlled devices 15 in the first current path and a second group of fully-controlled devices 16 in the first current path;

Example 3

Figure 4 shows Embodiment 3 of the present invention. As shown in Figure 4, this embodiment omits the first current path 1, and the entire DC circuit breaker is only composed of the second current path 2, the third current path 3 and the fourth current path 4, and the shut-off speed of the fault current is higher. Fast, but it also increases the conduction loss during normal operation of the system.

Example 4

Figure 5 shows Embodiment 4 of the present invention. As shown in FIG. 5 , a blocking power electronic switch module 100 is added between the first lead-out terminal of the first current path and the first lead-out terminal of the second current path. The blocking power electronic switch module 100 is composed of a fully-controlled device and a lightning arrester connected in parallel. The power electronic switch module 12 of the first current path 1 adopts a half-controlled device, and the third current path 3 only includes the capacitor module C1. When the DC transmission line appears When a short-circuit fault occurs, the power electronic switch module 100 is blocked from conduction, and the second current path semi-controlled device module 21 also receives a conduction signal, and then the third current path capacitor module C1 is discharged, and the first current path 1 is quickly switched to The third current path 3, the power electronic switch module 12 of the first current path is turned off naturally when the current of the power electronic switch module 12 crosses zero, and when the capacitor module C1 of the third current path enters the reverse charging process, the semi-controlled device module 21 of the second current path satisfies the conduction The condition is turned on, the current flows through the blocking power electronic module 100 and the second current path 2, and after the delay until the mechanical switch module 11 of the first current path 1 is turned off, the fully controlled device group in the power electronic switch module 100 is blocked Upon receiving the shutdown signal, the fault current is switched to the surge arrester path that blocks the power electronic switch module 100, and quickly decreases to zero.

In this embodiment, the blocking power electronic switch module 100 can also use a full-control device and a half-control device in series, and the first current path power electronic switch module 12 can use a full-control device or a full-control device. Type device and semi-controlled device in series, the second current path 2 may only include half-controlled device modules, or only include full-controlled device modules, or may be composed of both in series. The various composition methods mentioned above can be combined freely, and the control methods are slightly different.

Example 5

Fig. 6 is another embodiment of the present invention applicable to bipolar flexible direct current transmission occasions. As shown in FIG. 6 , the first lead-out terminal 61 of the first circuit breaker 60 is connected to the positive pole of the bipolar transmission line, and the second lead-out terminal 62 of the first circuit breaker 60 is connected to one end of the simulated short-circuit resistor. The first lead-out terminal 63 of the second circuit breaker 65 is connected to the negative pole of the bipolar power transmission line, and the second lead-out terminal 64 of the second circuit breaker 65 is connected to the other end of the simulated short-circuit resistance.

Claims (10)

1. A DC circuit breaker topological circuit, characterized in that: the DC circuit breaker consists of a first current path (1), a second current path (2), a third current path (3) and a fourth current path ( 4) composition; the first lead-out terminal of the fourth current path (4), the first lead-out terminal of the third current path (3), the first lead-out terminal of the second current path (2) and the first current path (1) The first lead-out terminals of the DC circuit breaker are connected together, as the first lead-out terminal (5) of the DC circuit breaker is connected to one end of the DC transmission line; the second lead-out terminal of the fourth current path (4), the third current path (3) The second lead-out terminal, the second lead-out terminal of the second current path (2) and the second lead-out terminal of the first current path (1) are connected together, as the second lead-out terminal (6) of the DC circuit breaker and the DC transmission line the other end of the connection; The first current path (1) is composed of a power electronic switch module (12) and a mechanical switch module (11); one end of the power electronic switch module (12) is connected to one end of the mechanical switch module (11), and the power electronic switch The other end of the module (12) serves as the second lead-out terminal of the first current path (1); The second current path (2) includes a half-controlled device module (21) and a full-controlled device module (22), and the anode of the half-controlled device module (21) is used as the first electrode of the second current path (2). Out terminal, the cathode of the half-controlled device module (21) is connected with one end (23) of the full-controlled device module (22); lead-out terminal; The third current path (3) is composed of a capacitor module (C1), and the capacitor module (C1) is composed of at least one capacitor unit connected in series or in parallel; The fourth current path (4) is composed of a voltage limiting device module, and the voltage limiting device module is composed of at least one voltage limiting device connected in series. 2. According to the DC circuit breaker topology circuit according to claim 1, it is characterized in that: when the DC transmission line is in normal operation, the mechanical switch module (11) of the first current path is in a closed state, and the power electronic switch of the first current path The module (12) is in a conduction state; when a line short circuit fault is detected, the second current path semi-controlled device module (21) and the second current path full-controlled device module (22) receive The signal is turned on, and at the same time the first current path power electronic switch module (12) is quickly turned off, blocking the fault current of the first current path (1), the mechanical switch module (11) starts to break, and the fault current is quickly transferred to the second Current path (2); when the contacts at both ends of the mechanical switch module (1) of the first current path are disconnected to a certain distance, the full-control device module (22) of the second current path (2) is quickly turned off, blocking When the fault current flows through the second current path (2), the current of the semi-controlled device module (21) in the second current path (2) crosses zero and turns off naturally, and the fault current is transferred to the third current path (3). The capacitor module (C1) of the three current paths is charged, and when the voltage across the capacitor module (C1) of the third current path (3) rises to the limit value of the fourth current path voltage limiting device module, the current flows from the third current path (3) ) is switched to the fourth current path (4), at this time, because the voltage across the capacitor module (C1) is at a value higher than that of the direct current transmission converter station, the fault current drops rapidly to zero. 3. The DC circuit breaker topology circuit according to claim 1, characterized in that: a voltage limiting device (7) is connected in parallel between the first terminal of the DC circuit breaker and ground, and the second terminal of the DC circuit breaker A voltage limiting device (8) is connected in parallel between the terminal and the ground. 4. The DC circuit breaker topology circuit according to claim 1, characterized in that: the second current path semi-controlled device module (21) is composed of at least one semi-controlled device in series, and the second current path is fully controlled The type device module (22) is composed of at least one full-control type device connected in series. 5. According to the DC breaker topology circuit according to claim 1, it is characterized in that: the second current path semi-controlled device module (21) is composed of at least one anti-parallel semi-controlled device unit (24) in series, The second current path fully-controlled device module (22) is composed of a first group of fully-controlled devices (25) in the second current path and a second group of fully-controlled devices (26) in the second current path in reverse series; The first group of full-control devices (25) and the second group of full-control devices (26) are composed of at least one full-control device connected in series in the same direction; the first current path full-control device module consists of the first current path second It is composed of a group of fully controlled devices (15) and a second group of fully controlled devices (16) in the first current path. 6. The DC circuit breaker topology circuit according to claim 1, characterized in that: said DC circuit breaker only includes the second current path (2), the third current path (3) and the fourth current path (4) . 7. The DC circuit breaker topology circuit according to claim 1, characterized in that: the first current path only includes a mechanical switch module (11), and the power electronic switch (12) of the first current path is replaced by a wire. 8. The DC circuit breaker topology circuit according to claim 1, characterized in that: said second current path (2) only includes full-control device modules (22). 9. The DC circuit breaker topology circuit according to claim 1, characterized in that: the second current path (2) only includes a semi-controlled device module (21); the first lead-out of the first current path A blocking power electronic switch module (100) composed of full-control devices is added between the terminal and the first lead-out terminal of the second current path. 10. The DC circuit breaker topology circuit according to claim 9, characterized in that: said blocking power electronic module (100) is composed of a semi-controlled device series module and a full-controlled device series module connected in series.