Current-limiting auxiliary commutation bidirectional fast circuit breaker

Abstract

The bidirectional fast circuit breaker comprises a through-flow branch, a commutation module, a current limiting module, a buffer branch and an energy consumption branch, the through-flow branch comprises a fast mechanical switch FMS, a coupling inductor L2, a power electronic switch S1 and a power electronic switch S2, the fast mechanical switch FMS and the coupling inductor L2 are connected in series, and the power electronic switch S1 and the power electronic switch S2 are reversely connected in series. A diode D1 and a diode D2 are respectively connected in parallel with a power electronic switch S1 and a power electronic switch S2, a capacitor C0 is connected in series with the power electronic switch S2, a resistor R0 is connected in parallel with the capacitor C0, a current-limiting inductor L1 is connected in series with a coupling inductor L2, a thyristor T1 and a thyristor T2 are reversely connected in parallel and then are connected in series with a resistor R so as to be connected in parallel with the two ends of the current-limiting inductor L1, and a buffer branch is connected in parallel with the two ends of a through-current branch. The buffer branch comprises a resistor R1 and a capacitor C1 which are connected in series, and the energy consumption branch is connected to the two ends of the through-current branch in parallel.

Description

Technical Field

[0001] The invention relates to the technical field of bidirectional fast circuit breakers, in particular to a bidirectional fast circuit breaker with current limiting and auxiliary commutation. Background Art

[0002] The DC transmission system has broad application prospects in the field of renewable energy grid-connected power generation due to its advantages of good economy, high reliability and low power loss. However, compared with the traditional AC transmission system, the DC transmission system faces more challenges in the field of fault protection. It is mainly manifested in the following two aspects: on the one hand, the DC grid line impedance is low, and the traditional DC circuit breaker has no fault current limiting function. When a fault occurs, the fault current will reach its peak value in a very short time, which seriously threatens the operation safety of the power grid; on the other hand, the rapid rise of short-circuit current puts high demands on the fault isolation speed of the circuit breaker. If the fault isolation is not timely, the fault current will break through the electrical equipment. Therefore, the research and development of DC circuit breakers with current limiting capabilities and shortened fault isolation time is of great significance for the protection of DC transmission systems.

[0003] Although mechanical DC circuit breakers have low operating losses and costs, their breaking speed is too slow and the fault isolation time is long. Solid-state DC circuit breakers have fast operating speeds, but high conduction losses and costs. Therefore, hybrid DC circuit breakers that combine the advantages of both have emerged. Hybrid DC circuit breakers are DC circuit breakers that use a combination of mechanical and semiconductor devices for mixed control. They combine the advantages of mechanical and solid-state DC circuit breakers and are currently important protection devices in DC transmission systems. Currently, there are problems with excessive short-circuit currents that cause the circuit breaker to be unable to safely cut off the fault current and low commutation voltages that cause commutation to be too slow.

[0004] The information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art. Summary of the invention

[0005] In view of the shortcomings or defects of the above-mentioned prior art, a bidirectional fast circuit breaker with current limiting and auxiliary commutation is provided, which can break the rated current, use the current limiting inductor to limit the short-circuit fault current rise rate, use the coupling inductor to increase the voltage at both ends of the commutation branch, improve the commutation capacity, and use the commutation module to improve the breaking capacity of the semiconductor switching device to break the short-circuit fault, thereby solving the problem that the circuit breaker cannot cut off the fault in time due to the excessive fault current rise rate during the breaking process.

[0006] The purpose of the present invention is achieved through the following technical solutions.

[0007] A bidirectional fast circuit breaker with current limiting auxiliary commutation includes a current-passing branch, a commutation module, a current limiting module, a buffer branch and an energy consumption branch, wherein:

[0008] The current branch includes a fast mechanical switch FMS and a coupled inductor L in series. 2 ,

[0009] A commutation module is connected in parallel to both ends of the flow branch, and the commutation module includes:

[0010] Power Electronic Switch 1 and power electronic switch S 2 , the two are connected in reverse series,

[0011] Diode D 1 and diode D 2 , which are connected in parallel with power electronic switches S 1 and power electronic switch S 2 ,

[0012] Capacitor C 0 , which is connected in series with the power electronic switch S 2 ,

[0013] Resistor R 0 , which is connected in parallel with the capacitor C 0 ,

[0014] A current limiting module is connected in series with the current-carrying branch to limit the rising rate of the short-circuit fault current. The current limiting module includes:

[0015] Current limiting inductor L 1 , which is connected in series with the coupling inductor L 2 ,

[0016] Thyristor 1 and thyristor T 2 , the two are connected in reverse parallel, and the series resistor R is connected in parallel with the current limiting inductor L 1 Both ends,

[0017] A buffer branch is connected in parallel to both ends of the current-carrying branch, and the buffer branch includes a resistor R connected in series. 1 and capacitor C 1 ,

[0018] The energy consumption branch is connected in parallel to the two ends of the flow branch.

[0019] In the current-limiting auxiliary commutation bidirectional fast circuit breaker, the energy-consuming branch includes a metal oxide arrester MOV.

[0020] In the bidirectional fast circuit breaker with current limiting auxiliary commutation, when the system is normally flowing, the system current flows through the fast mechanical switch FMS and the coupling inductor L of the current branch. 2When a short circuit occurs in the system, the system current rises rapidly. At this time, the current limiting inductor L 1 and coupled inductor L 2 Limit the short-circuit current rise rate, current limiting inductor L 1 Overvoltage is induced in the circuit, absorbing line energy while limiting current; when fault current is detected, the fast mechanical switch FMS opens and the power electronic switch S is turned on at the same time 1 At this time, the current is transferred from the flow branch to the commutation module, and the coupling inductor L 2 When the fault current increases rapidly, overvoltage is generated at both ends, thereby increasing the voltage at both ends of the commutation module and accelerating the commutation process. At the same time, the capacitor C 0 and resistor R 0 Limit the rising rate of fault current; when the fault current is completely transferred to the commutation module, turn off the power electronic switch S 1 , the converter module generates overvoltage, and the current of the converter module gradually transfers to the buffer branch; when the voltage at both ends of the buffer branch reaches the action voltage of the metal oxide surge arrester MOV, the resistance of the energy dissipation branch decreases rapidly, and the fault current is dissipated through the metal oxide surge arrester MOV. At this time, the thyristor T is turned on. 1 , current limiting inductor L 1 The remaining energy is dissipated through the resistor R.

[0021] In the bidirectional fast circuit breaker with current limiting and auxiliary commutation, the fast mechanical switch FMS is a vacuum high-speed mechanical switch based on electromagnetic repulsion or a vacuum mechanical switch based on high-speed motor drive.

[0022] In the bidirectional fast circuit breaker with current limiting auxiliary commutation, the current limiting inductor L 1 and coupled inductor L 2 It both limits the current and increases the current commutation.

[0023] In the current limiting auxiliary commutation bidirectional fast circuit breaker, the thyristor T 1 and thyristor T 2 It is a unidirectional semi-controlled device.

[0024] In the bidirectional fast circuit breaker with current limiting auxiliary commutation, the power electronic switch S 1 and power electronic switch S 2 They are all insulated gate bipolar transistors IGBT or fully controlled devices integrated gate commutated thyristors IGCT.

[0025] In the bidirectional fast circuit breaker with current limiting auxiliary commutation, the diode D 1 and diode D 2 Reverse arrangement.

[0026] In the bidirectional fast circuit breaker with current limiting auxiliary commutation, the current limiting inductor L1 and coupled inductor L 2 The inductance values ​​are the same.

[0027] In the bidirectional fast circuit breaker with current limiting auxiliary commutation, the diode D 1 and diode D 2 The structure is the same.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] The present invention can interrupt the rated current. At the same time, the current limiting inductor L 1 To limit the short-circuit fault current rise rate, use the coupled inductor L 1 and L 2 To increase the voltage at both ends of the commutation branch and improve the commutation capacity. The commutation module is used to improve the breaking capacity of the semiconductor switch device to break the short-circuit fault, solving the problem that the circuit breaker cannot cut off the fault in time due to the excessive rise rate of the fault current during the breaking process.

[0030] The above description is only an overview of the technical solution of the present invention. In order to make the technical means of the present invention clearer and to achieve the extent that those skilled in the art can implement it according to the contents of the specification, and in order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are exemplified below. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] By reading the detailed description of the preferred specific embodiments below, various other advantages and benefits of the present invention will become clear to those of ordinary skill in the art. The drawings in the specification are only for the purpose of illustrating the preferred embodiments and are not considered to be limitations of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings without creative work. Moreover, the same reference numerals are used to represent the same components throughout the drawings.

[0032] In the attached picture:

[0033] Figure 1 It is a structural schematic diagram of a circuit breaker for current limiting auxiliary commutation;

[0034] Figure 2(a) to Figure 2(d) It is a schematic diagram of the short-circuit breaking process when the forward current of the current-limiting auxiliary commutation circuit breaker of the present invention is turned off;

[0035] Figure 3(a) to Figure 3(d) It is a schematic diagram of the short-circuit breaking process when the reverse current of the current-limiting auxiliary commutation circuit breaker of the present invention is turned off.

[0036] The present invention is further explained below in conjunction with the accompanying drawings and embodiments. DETAILED DESCRIPTION

[0037] The specific embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although the specific embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present invention and to enable the scope of the present invention to be fully communicated to those skilled in the art.

[0038] It should be noted that certain words are used in the specification and claims to refer to specific components. Those skilled in the art should understand that technicians may use different nouns to refer to the same component. This specification and claims do not use the difference in nouns as a way to distinguish components, but use the difference in the functions of the components as the criterion for distinction. As mentioned throughout the specification and claims, "including" or "comprising" is an open term, so it should be interpreted as "including but not limited to". The subsequent description of the specification is a preferred embodiment of the present invention, but the description is based on the general principles of the specification and is not intended to limit the scope of the present invention. The scope of protection of the present invention shall be determined by the attached claims.

[0039] To facilitate understanding of the embodiments of the present invention, several specific embodiments will be further explained below with reference to the accompanying drawings, and each of the accompanying drawings does not constitute a limitation on the embodiments of the present invention.

[0040] For a better understanding, Figure 1 to Figure 3(d) As shown, a bidirectional fast circuit breaker with current limiting auxiliary commutation includes a current-passing branch, a commutation module, a current limiting module, a buffer branch and an energy consumption branch, wherein:

[0041] The current branch includes a fast mechanical switch FMS and a coupled inductor L in series. 2 ,

[0042] A commutation module is connected in parallel to both ends of the flow branch, and the commutation module includes:

[0043] Power Electronic Switch 1 and power electronic switch S 2 , the two are connected in reverse series,

[0044] Diode D 1 and diode D 2 , which are connected in parallel with power electronic switches S 1 and power electronic switch S 2 ,

[0045] Capacitor C 0, which is connected in series with the power electronic switch S 2 ,

[0046] Resistor R 0 , which is connected in parallel with the capacitor C 0 ,

[0047] A current limiting module is connected in series with the current-carrying branch to limit the rising rate of the short-circuit fault current. The current limiting module includes:

[0048] Current limiting inductor L 1 , which is connected in series with the coupling inductor L 2 ,

[0049] Thyristor 1 and thyristor T 2 , the two are connected in reverse parallel, and the series resistor R is connected in parallel with the current limiting inductor L 1 Both ends,

[0050] A buffer branch is connected in parallel to both ends of the current-carrying branch, and the buffer branch includes a resistor R connected in series. 1 and capacitor C 1 ,

[0051] The energy consumption branch is connected in parallel to the two ends of the flow branch.

[0052] In a preferred embodiment of the current-limiting auxiliary commutation bidirectional fast circuit breaker, the energy-consuming branch includes a metal oxide arrester MOV.

[0053] In a preferred embodiment of the current-limiting auxiliary commutation bidirectional fast circuit breaker, when the system is normally flowing, the system current flows through the fast mechanical switch FMS and the coupling inductor L of the current branch. 2 When a short circuit occurs in the system, the system current rises rapidly. At this time, the current limiting inductor L 1 and coupled inductor L 2 Limit the short-circuit current rise rate, current limiting inductor L 1 Overvoltage is induced in the circuit, absorbing line energy while limiting current; when fault current is detected, the fast mechanical switch FMS opens and the power electronic switch S is turned on at the same time 1 At this time, the current is transferred from the flow branch to the commutation module, and the coupling inductor L 2 When the fault current increases rapidly, overvoltage is generated at both ends, thereby increasing the voltage at both ends of the commutation module and accelerating the commutation process. At the same time, the capacitor C 0 and resistor R 0 Limit the rising rate of fault current; when the fault current is completely transferred to the commutation module, turn off the power electronic switch S 1, the converter module generates overvoltage, and the current of the converter module gradually transfers to the buffer branch; when the voltage at both ends of the buffer branch reaches the action voltage of the metal oxide surge arrester MOV, the resistance of the energy dissipation branch decreases rapidly, and the fault current is dissipated through the metal oxide surge arrester MOV. At this time, the thyristor T is turned on. 1 , current limiting inductor L 1 The remaining energy is dissipated through the resistor R.

[0054] In a preferred embodiment of the bidirectional fast circuit breaker with current limiting auxiliary commutation, the fast mechanical switch FMS is a vacuum high-speed mechanical switch based on electromagnetic repulsion or a vacuum mechanical switch based on high-speed motor drive.

[0055] In a preferred embodiment of the current limiting auxiliary commutation bidirectional fast circuit breaker, the current limiting inductor L 1 and coupled inductor L 2 It both limits the current and increases the current commutation.

[0056] In a preferred embodiment of the current limiting auxiliary commutation bidirectional fast circuit breaker, the thyristor T 1 and thyristor T 2 It is a unidirectional semi-controlled device.

[0057] In a preferred embodiment of the current limiting auxiliary commutation bidirectional fast circuit breaker, the power electronic switch S 1 and power electronic switch S 2 They are all insulated gate bipolar transistors IGBT or fully controlled devices integrated gate commutated thyristors IGCT.

[0058] In the preferred embodiment of the current limiting auxiliary commutation bidirectional fast circuit breaker, the diode D 1 and diode D 2 Reverse arrangement.

[0059] In the preferred embodiment of the current limiting auxiliary commutation bidirectional fast circuit breaker, the current limiting inductor L 1 and coupled inductor L 2 The inductance values ​​are the same.

[0060] In the preferred embodiment of the current limiting auxiliary commutation bidirectional fast circuit breaker, the diode D 1 and diode D 2 The structure is the same.

[0061] In one embodiment, Figure 1 The schematic diagram of the circuit breaker structure includes a flow branch, a commutation module, a current limiting module, a buffer branch, and an energy consumption branch. The flow branch is composed of a fast mechanical switch FMS, a coupled inductor L 2 The commutation module consists of a power electronic switch S 1 and S2 , diode D 1 and D 2 , capacitor C 0 and resistor R 0 The current limiting module consists of a current limiting inductor L 1 , resistor R, thyristor T 1 and T 2 The buffer branch is composed of resistor R 1 and capacitor C 1 The energy consumption branch is composed of metal oxide surge arrester MOV.

[0062] (1) The current branch is composed of a fast mechanical switch FMS and a coupled inductor L 2 composition.

[0063] (2) The commutation module consists of a power electronic switch S 1 and S 2 , diode D 1 and D 2 , capacitor C 0 and resistor R 0 composition.

[0064] (3) The current limiting module consists of a current limiting inductor L 1 , resistor R, thyristor T 1 and T 2 Composition, can limit the short-circuit fault current rise rate.

[0065] (4) The buffer branch is composed of a resistor R 1 and capacitor C 1 composition.

[0066] (5) The energy consumption branch is composed of a metal oxide surge arrester MOV.

[0067] When the system is normally flowing, the system current flows through the fast mechanical switch FMS and the coupled inductor L of the current branch. 2 When a short circuit occurs in the system, the system current rises rapidly. At this time, the current limiting inductor L 1 and coupled inductor L 2 The existence of will limit the short-circuit current rise rate, the current limiting inductor L 1 Overvoltage will be induced in the circuit, absorbing line energy while limiting current; when fault current is detected, the fast mechanical switch FMS opens and turns on the power electronic switch S of the commutation module. 1 At this time, the current is transferred from the fast mechanical switch branch to the commutation module, and the coupling inductor L 2 When the fault current increases rapidly, overvoltage will be generated at both ends, thereby increasing the voltage at both ends of the converter module and accelerating the commutation process. 0 and R 0The existence of will also limit the rising rate of the fault current; when the fault current is completely transferred to the converter module, the power electronic switch S of the converter module is turned off. 1 At this time, overvoltage will be generated at both ends of the branch, and the current of the converter module will gradually transfer to the buffer branch; when the voltage at both ends of the branch reaches the action voltage of the metal oxide surge arrester MOV, the resistance of the energy dissipation branch decreases rapidly, and the fault current is dissipated through the metal oxide surge arrester MOV. At this time, the thyristor T is turned on. 1 , current limiting inductor L 1 The remaining energy is dissipated through the resistor R.

[0068] Figure 2(a) to Figure 2(d) The short-circuit breaking process of the circuit breaker is given. Figure 2(a) to Figure 2(d) Describe this disconnection process.

[0069] (1) As shown in Figure 2(a), in the normal flow state of the system, the current flows through the fast mechanical switch FMS and the coupled inductor L 2。

[0070] (2) As shown in Figure 2(b), when a short circuit occurs in the system, the system current rises rapidly. At this time, the coupled inductor L 1 and L 2 The existence of will limit the short-circuit current rise rate, the current limiting inductor L 1 Overvoltage will be induced in the circuit, absorbing line energy while limiting current; when fault current is detected, the fast mechanical switch FMS opens and turns on the power electronic switch S of the commutation module. 1 At this time, the current is transferred from the fast mechanical switch branch to the commutation module, and the coupling inductor L 2 When the fault current increases rapidly, overvoltage will be generated at both ends, thereby increasing the voltage at both ends of the converter module and accelerating the commutation process. 0 and R 0 The presence of will also limit the rate of rise of the fault current.

[0071] (3) As shown in Figure 2(c), when the fault current is completely transferred to the converter module, the power electronic switch S of the converter module is turned off. 1 At this time, overvoltage will be generated at both ends of the branch, and the current of the converter module will gradually transfer to the buffer branch.

[0072] (4) As shown in Figure 2(d), when the voltage across the branch reaches the MOV action voltage, the energy dissipation branch resistance decreases rapidly, and the fault current is dissipated through the MOV. At this time, the thyristor T is turned on. 1 , current limiting inductor L 1 The remaining energy is dissipated through the resistor R.

[0073] Figure 3(a) to Figure 3(d) A schematic diagram of the short-circuit breaking process of the current-limiting auxiliary commutation type circuit breaker during reverse current shutdown is given, which is similar to the schematic diagram during forward current shutdown.

[0074] The basic principles of the present application are described above in conjunction with specific embodiments. However, it should be noted that the advantages, strengths, effects, etc. mentioned in the present application are only examples and not limitations, and it cannot be considered that these advantages, strengths, effects, etc. are required by each embodiment of the present application. In addition, the specific details disclosed above are only for the purpose of illustration and ease of understanding, not for limitation, and the above details do not limit the present application to being implemented by adopting the above specific details.

[0075] The above description has been given for the purpose of illustration and description. In addition, this description is not intended to limit the embodiments of the present application to the forms disclosed herein. Although multiple example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, changes, additions and sub-combinations thereof.

Claims

1. A bidirectional fast circuit breaker with current limiting and auxiliary commutation, characterized in that: It includes a flow branch, a commutation module, a current limiting module, a buffer branch and an energy consumption branch, wherein: The current branch includes a fast mechanical switch FMS and a coupled inductor L2 in series. A commutation module is connected in parallel to both ends of the flow branch, and the commutation module includes: The power electronic switch S1 and the power electronic switch S2 are connected in reverse series. Diode D1 and diode D2 are connected in parallel with power electronic switch S1 and power electronic switch S2 respectively. Capacitor C0, which is connected in series with the power electronic switch S2, The resistor R0 is connected in parallel with the capacitor C0. A current limiting module is connected in series with the current-carrying branch to limit the rising rate of the short-circuit fault current. The current limiting module includes: The current limiting inductor L1 is connected in series with the coupling inductor L2. Thyristor T1 and thyristor T2 are connected in reverse parallel and then connected in series with resistor R to connect the two ends of current limiting inductor L1 in parallel. A buffer branch is connected in parallel to both ends of the current-passing branch, and the buffer branch includes a resistor R1 and a capacitor C1 connected in series. The energy consumption branch is connected in parallel to the two ends of the flow branch.

2. The bidirectional fast circuit breaker with current limiting and auxiliary commutation according to claim 1, characterized in that: Preferably, the energy dissipation branch includes a metal oxide arrester MOV.

3. The bidirectional fast circuit breaker with current limiting and auxiliary commutation as claimed in claim 2, characterized in that: When the system is normally conducting, the system current flows through the fast mechanical switch FMS and the coupled inductor L2 of the conducting branch.

4. The bidirectional fast circuit breaker with current limiting and auxiliary commutation according to claim 1, characterized in that: The fast mechanical switch FMS is a vacuum high-speed mechanical switch based on electromagnetic repulsion or a vacuum mechanical switch based on high-speed motor drive.

5. The bidirectional fast circuit breaker with current limiting and auxiliary commutation according to claim 1, characterized in that: The current limiting inductor L1 and the coupling inductor L2 both limit the current and increase the current commutation.

6. The bidirectional fast circuit breaker with current limiting and auxiliary commutation according to claim 1, characterized in that: The thyristor T1 and the thyristor T2 are unidirectionally conducting half-controlled devices.

7. The bidirectional fast circuit breaker with current limiting and auxiliary commutation according to claim 1, characterized in that: The power electronic switch S1 and the power electronic switch S2 are both insulated gate bipolar transistors IGBT or fully controlled devices, integrated gate-commutated thyristors IGCT.

8. The bidirectional fast circuit breaker with current limiting and auxiliary commutation according to claim 1, characterized in that: The diode D1 and the diode D2 are arranged in opposite directions.

9. The bidirectional fast circuit breaker with current limiting and auxiliary commutation according to claim 1, characterized in that: The current limiting inductor L1 and the coupled inductor L2 have the same inductance value.

10. The bidirectional fast circuit breaker with current limiting and auxiliary commutation according to claim 1, characterized in that: The diode D1 and the diode D2 have the same structure.

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