阅读说明：本技术 一种具有强迫换流功能的混合式直流断路器 (Hybrid direct current breaker with forced commutation function ) 是由 李新 时珊珊 吴益飞 王皓靖 刘舒 魏新迟 吴翊 杨飞 于 2020-10-30 设计创作，主要内容包括：一种具有强迫换流功能的混合式直流断路器,由主电流回路、电流转移支路、能量耗散支路、续流支路和控制系统组成。正常通流状态下,系统电流从主回路流过,高速机械开关承担额定通流。关断额定电流时,触发高速机械开关和相应电力电子器件导通,预充电电容放电,电流被强迫转移至电流转移支路,由电流转移支路关断额定电流后,避雷器导通完成开断。当发生短路故障时,触发高速机械开关和相应电力电子器件导通,预充电电容放电开始换流,电流首先转移至电流转移支路,由电流转移支路关断短路电流后,避雷器导通完成开断。所述新型电流转移直流断路器具有电流转移速度快,开断能力强、断口恢复特性好等特点。(A hybrid direct current circuit breaker with a forced commutation function comprises a main current loop, a current transfer branch, an energy dissipation branch, a follow current branch and a control system. In a normal through-flow state, system current flows from the main loop, and the high-speed mechanical switch bears rated through-flow. When the rated current is cut off, the high-speed mechanical switch and the corresponding power electronic device are triggered to be conducted, the pre-charging capacitor discharges, the current is forcedly transferred to the current transfer branch, and after the rated current is cut off by the current transfer branch, the lightning arrester is conducted to complete the cut-off. When short-circuit fault occurs, the high-speed mechanical switch and the corresponding power electronic device are triggered to be conducted, the pre-charging capacitor discharges to start commutation, the current is firstly transferred to the current transfer branch, and after the short-circuit current is cut off by the current transfer branch, the lightning arrester is conducted to complete disconnection. The novel current transfer direct current breaker has the characteristics of high current transfer speed, strong breaking capacity, good fracture recovery characteristic and the like.)

1. The utility model provides a hybrid direct current circuit breaker with forced commutation function, comprises main current circuit, current transfer branch road, energy dissipation branch road, afterflow branch road and on-line monitoring system control system, and wherein main current circuit, current transfer branch road, energy dissipation branch road, after the afterflow branch road is parallelly connected, draw forth through terminal A1 and A2, its characterized in that:

(1) two ends of a break port of the high-speed mechanical switch of the main current loop are directly connected with circuit breaker outlet terminals A1 and A2;

(2) in the current transfer branch: the diode D1 is connected in anti-parallel with two ends of the full-control power semiconductor device T1, and after the capacitor C and the resistor R are connected in series, the diode D1 is connected in parallel with two ends of the T1; the diode D2 is connected in anti-parallel at two ends of a full-control power semiconductor device T2, a capacitor C and a resistor R are connected in series and then connected in parallel at two ends of T2, the zinc oxide arrester is connected in parallel at two ends of T1 and T2 respectively, T1 and T2 are connected in series in an anti-reverse direction to form a solid-state switch component, one or more solid-state switch components and a pre-charging capacitor are connected in series to form a current transfer branch, and two ends of the current transfer branch are connected in parallel at two ends of a main loop;

(3) in the energy dissipation branch: an energy dissipation branch is formed by a lightning arrester (MOV), the MOV1 is connected in parallel at two ends of the T1, and the MOV2 is connected in parallel at two ends of the T2;

(4) in the follow current branch: the semi-controlled power semiconductor devices T3 and T4 are connected in anti-parallel to form a follow current branch circuit, and the follow current branch circuit is connected in parallel at two ends of a main current loop;

(5) the online monitoring system measures the current flowing through the outlet terminal A1 or A2 and the current direction, the current flowing through the main current loop, the current flowing through the current transfer branch, the current flowing through the energy dissipation branch, the voltage across the high-speed mechanical switch and the switch displacement of the high-speed mechanical switch, controls the action of the high-speed mechanical switch HSS and the power semiconductor device of the current transfer branch by measuring the current amplitude and the change rate of the main current loop when the system current direction is from A1 to A2, and controls the action of the high-speed mechanical switch HSS and the power semiconductor device of the current transfer branch by measuring the current amplitude and the change rate of the main current loop when the system current direction is from A2 to A1.

2. The circuit breaker of claim 1, wherein:

in a normal through-current state of the system, system current flows through the main current loop, the high-speed mechanical switch bears rated through-current, all power semiconductor devices of the current transfer branch are not triggered at the moment, the conduction threshold of the energy dissipation branch is lower than the system voltage, and no current flows;

when the rated current is turned off, the control system sends a brake-off action instruction to the high-speed mechanical switch HSS, the high-speed mechanical switch acts, then the control system triggers the power semiconductor device according to a specific time sequence according to the information returned by the sensor and the flow direction of the current of the circuit breaker, the pre-charging capacitor discharges, the current is forcedly transferred to the current transfer branch, after the current of the main loop crosses zero, the follow current branch is triggered to conduct and carry out follow current, finally the solid-state switch is turned off according to the time sequence, the current is transferred to the energy dissipation branch, and the rated current is turned;

when short-circuit fault occurs, a control system sends a brake-separating instruction, the control system sends a brake-separating action instruction to a high-speed mechanical switch HSS, the high-speed mechanical switch acts, according to information returned by a sensor and the flow direction of current of a circuit breaker, the control system triggers the power semiconductor device of a current transfer branch circuit to be conducted according to a specific time sequence, a pre-charging capacitor discharges electricity, current of a main circuit is forced to flow into the current transfer branch circuit, after the current of the main circuit crosses zero, a follow current branch circuit is triggered to be conducted to carry out follow current, then a solid-state switch is turned off according to the time sequence, the current is finally transferred to an energy dissipation branch circuit.

3. The circuit breaker of claim 1, wherein the online monitoring system features comprise: the current sensor comprises a current sensor G0 for measuring the current state of a system, a current sensor G1 for measuring the current state of a main loop, a current sensor G2 for measuring the current state of a current transfer branch circuit, a current sensor G3 for measuring the current state of an over-energy dissipation branch circuit, a voltage sensor Vhs for measuring the fracture voltage of a high-speed mechanical switch HSS, a displacement sensor Pd for measuring the motion state of the high-speed mechanical switch, and an A/D conversion module and a communication module of a corresponding signal conditioning circuit.

4. The circuit breaker of claim 1, the control system features comprising: the device comprises a human-computer interaction module, a current filtering processing module, a main loop current di/dt calculating module and a communication module.

5. The circuit breaker of claim 1, wherein: the high-speed mechanical switch is a high-speed mechanical switch based on electromagnetic repulsion, a mechanical switch based on high-speed motor drive or a high-speed mechanical switch based on explosion drive.

6. The circuit breaker of claim 1, wherein: the fully-controlled power semiconductor devices T1-T2 are fully-controlled devices which are in one-way conduction, can be single devices or combinations of the following devices, such as IGBTs, IGCTs or IEGT, and the semi-controlled power semiconductor devices T3-T5 are fully-semi-controlled devices which are in one-way conduction, such as thyristors.

7. The circuit breaker according to any one of claims 1-6, wherein: the energy dissipation branches include, but are not limited to, the following devices, either alone or in combination: the lightning arrester comprises a metal oxide lightning arrester, a line type metal oxide lightning arrester, a gapless line type metal oxide lightning arrester, a fully-insulated composite outer sleeve metal oxide lightning arrester and a detachable lightning arrester.

Technical Field

The invention relates to a hybrid direct current breaker with a forced commutation function, which realizes rapid transfer of fault current by discharge of a pre-charging capacitor and offset of main loop current. The time sequence of the power semiconductor device of the trigger current transfer branch circuit is changed, and the function of cutting off the currents in different current directions is achieved.

Background

The direct current breaker is used as a vital protection element in a direct current distribution system and is used for rapidly breaking direct current fault current and ensuring safe operation of the system. The solid-state direct current circuit breaker based on the power electronic device has high full current range switching-on and switching-off speed and high reliability, but because the high-power electronic device is connected in series in a rated through-current loop, the on-state loss is large, the manufacturing cost is relatively high, and the industrial large-scale application is difficult to realize; the traditional mechanical direct current circuit breaker has low rated through-current loss and strong breaking capacity, but has long breaking time of small current and poor fracture insulation recovery. Aiming at the defects of the two switching schemes, the direct current circuit breaker scheme combining the mechanical switch and the solid-state switch transfer has the advantages of high switching speed, good fracture insulation recovery, high reliability and the like, and can meet the requirements of safety, reliability and economy of the current direct current power distribution network.

Disclosure of Invention

In view of the above-mentioned shortcomings or drawbacks of the prior art, an object of the present invention is to provide a novel hybrid circuit breaker and a control method thereof. The full-control power semiconductor device of the current transfer branch circuit is triggered to be conducted according to the loop current and the specific time sequence by controlling the action of the high-speed mechanical switch HSS, so that the current breaking is completed.

Specifically, the invention adopts the following technical scheme:

a hybrid direct current circuit breaker with a forced commutation function comprises a main current loop, a current transfer branch, an energy dissipation branch, a follow current branch, an online monitoring system and a control system. The main current loop, the current transfer branch circuit and the energy dissipation branch circuit are connected in parallel after follow current, and are led out through the wire outlet ends A1 and A2. The method is characterized in that:

(1) two ends of a break port of the high-speed mechanical switch of the main current loop are directly connected with circuit breaker outlet terminals A1 and A2;

(2) in the current transfer branch: the diode D1 is connected in anti-parallel with two ends of the full-control power semiconductor device T1, and after the capacitor C and the resistor R are connected in series, the capacitor C and the resistor R are connected in parallel with two ends of the T1; the diode D2 is connected in parallel with the two ends of the full-control power semiconductor device T2 in an anti-parallel mode, the capacitor C and the resistor R are connected in series and then connected in parallel with the two ends of the T2, and the zinc oxide lightning arrester is connected in parallel with the two ends of the T1 and the T2 respectively. The T1 and the T2 are reversely connected in series to form a solid-state switch component, one or more solid-state switch components are connected in series with the pre-charging capacitor to form a current transfer branch circuit, and two ends of the current transfer branch circuit are connected in parallel to two ends of the main circuit;

(3) in the energy dissipation branch: the energy dissipation branch is formed by an arrester (MOV), the MOV1 is connected in parallel at two ends of the T1, and the MOV2 is connected in parallel at two ends of the T2.

(4) The online monitoring system measures the current flowing through the outlet terminal A1 or A2 and the current direction, the current flowing through the main current loop, the current flowing through the current transfer branch circuit, the voltage at two ends of the high-speed mechanical switch and the switch displacement of the high-speed mechanical switch, when the system current direction is from A1 to A2, the high-speed mechanical switch HSS and the power semiconductor device of the current transfer branch circuit are controlled to operate by measuring the current amplitude and the change rate of the main current loop, and when the system current direction is from A2 to A1, the high-speed mechanical switch HSS and the power semiconductor device of the current transfer branch circuit are controlled to operate by measuring the current amplitude and the change rate of the main current loop.

Wherein the online monitoring system features include: the circuit breaker comprises a current sensor G0 for measuring the current state of a system, a current sensor G1 for measuring the current state of a main loop, a current sensor G2 for measuring the current state of a current transfer branch circuit, a current sensor G3 for measuring the current state of an energy dissipation branch circuit, a voltage sensor Vhs for measuring the fracture voltage of an HSS (home subscriber server) of a high-speed mechanical switch, a displacement sensor Pd for measuring the motion state of the high-speed mechanical switch, a temperature sensor D4 for measuring the ambient temperature of the circuit breaker, and an A/D conversion module and a communication module of a corresponding signal conditioning circuit;

wherein the control system features include: the device comprises a human-computer interaction module, a current filtering processing module, a main loop current di/dt calculating module and a communication module;

wherein the high-speed mechanical switch of the circuit breaker is characterized in that: the high-speed mechanical switch is a high-speed mechanical switch based on electromagnetic repulsion, a mechanical switch based on high-speed motor drive or a high-speed mechanical switch based on explosion drive.

Wherein the circuit breaker full-control type power semiconductor device is characterized in that: the fully-controlled power semiconductor devices T1-T2 are fully-controlled devices which are in one-way conduction, and can be single devices or combinations of the following devices, namely IGBTs, IGCTs or IEGTs.

Wherein the circuit breaker semi-controlled power semiconductor device is characterized in that: the semi-controlled power semiconductor devices T3-T5 are all semi-controlled devices which are in one-way conduction, such as thyristors.

Wherein, the circuit breaker energy dissipation branch road characterized in that: the energy dissipation branches include, but are not limited to, the following devices, either alone or in combination: the lightning arrester comprises a metal oxide lightning arrester, a line type metal oxide lightning arrester, a gapless line type metal oxide lightning arrester, a fully-insulated composite outer sleeve metal oxide lightning arrester and a detachable lightning arrester.

Drawings

Fig. 1 is a schematic structural view of a circuit breaker body;

FIG. 2 is a schematic diagram of a circuit breaker control system sensor distribution;

fig. 3 is a schematic diagram of the operation of the circuit breaker of the present invention when the rated current is cut off;

fig. 4 is a schematic diagram of the operation of the circuit breaker of the present invention when the short circuit current is cut off;

FIG. 5 presents a one-way disconnect topology of the present invention;

FIG. 6 illustrates a two-way disconnect topology of the present invention;

fig. 7 shows a two-way disconnection topology of the present invention.

Detailed Description

The following describes embodiments of the present invention with reference to the drawings.

Fig. 1 is a schematic structural diagram of a circuit breaker body, which includes a main current loop, a current transfer branch, a follow current branch, and an energy dissipation branch. Fig. 2 shows the distribution of sensors in the circuit breaker. Which comprises the following steps: the current sensor G0 is used for measuring the current state of the system, the current sensor G1 is used for measuring the current state of the main circuit, the sensor G2 is used for measuring the current state of the current transfer branch circuit, the current sensor G3 is used for measuring the current state of the over-energy dissipation branch circuit, the voltage sensor Vhs is used for measuring the fracture voltage of the HSS of the high-speed mechanical switch, the displacement sensor Pd is used for measuring the motion state of the high-speed mechanical switch, and the temperature sensor D4 is used for measuring the ambient temperature of the circuit breaker.

Fig. 3 shows the current transfer process during the specific breaking of rated current of the circuit breaker:

(1) as shown in fig. 3(a), in a normal through-current state, a system current flows in from the outlet terminal a1, passes through the mechanical switch HSS, and then flows out from the outlet terminal a 2;

(2) as shown in fig. 3(b), when the control system receives the rated on/off signal, the control system issues an opening command, and the high-speed mechanical switch HSS is turned on to start arcing.

(3) As shown in fig. 3(c), after a time delay, the control system triggers the current transfer branch to conduct, the pre-charge capacitor discharges, the main circuit current is forced to flow to the current transfer branch, and after the main circuit current crosses zero, the follow current branch is triggered to conduct to follow current.

(4) As shown in fig. 3(d), after the current is transferred to the current transfer branch, the current transfer branch directly turns off the current to complete the rated current switching;

(5) as shown in fig. 3(e), the system energy is ultimately dissipated in the MOV;

(6) when the current flows to the opposite direction, the current transfer mode and the time sequence in the current transfer process are the same as those in the forward current switching-off process;

fig. 4 shows the current transfer process during the specific process of breaking the short-circuit current of the circuit breaker:

(1) as shown in fig. 4(a), in a normal through-current state, a system current flows in from the outlet terminal a1, passes through the mechanical switch HSS, and then flows out from the outlet terminal a 2;

(2) as shown in fig. 4(b), when the detection system detects that a short-circuit fault occurs in the system, the detection system notifies the control system, the control system sends a brake opening instruction, the high-speed mechanical switch HSS is turned on, and the arc ignition is started.

(3) As shown in fig. 4(c), after a time delay, the control system triggers the current transfer branch to conduct, the pre-charge capacitor discharges, the main circuit current is forced to flow to the current transfer branch, and after the main circuit current crosses zero, the follow current branch is triggered to conduct to follow current.

(4) As shown in fig. 4(d), after the current is transferred to the current transfer branch, the current transfer branch directly turns off the current to complete the short-circuit current breaking;

(5) as shown in fig. 4(e), the system energy is ultimately dissipated in the MOV;

(6) when the current flows to the opposite direction, the current transfer mode and the time sequence in the current transfer process are the same as those in the forward current switching-off process;

the above is a detailed description of the present invention with reference to specific preferred embodiments, and it should not be considered that the present invention is limited to the specific preferred embodiments, and it will be apparent to those skilled in the art that several simple deductions or replacements can be made without departing from the concept of the present invention, for example, a unidirectional dc circuit breaker based on a unidirectional current transfer branch and a unidirectional oscillation branch, etc., and all should be considered as belonging to the protection scope of the present invention as determined by the appended claims.