High-voltage direct-current circuit breaker

Abstract

The utility model discloses a high-voltage direct-current circuit breaker, which comprises a main through-flow branch, a transfer branch and a voltage-limiting energy consumption branch, the main through-flow branch comprises a quick circuit breaker and a Hall current sensor which are connected in series, and the quick circuit breaker adopts an eddy current repulsion mechanism; the transfer branch is connected in parallel to the two ends of the main through-flow branch and comprises a high-voltage capacitor and an inductor which are sequentially connected in series, the high-voltage capacitor is connected with a charging power supply through a charging circuit, and the inductor is connected to the main through-flow branch through a vacuum trigger tube; the charging circuit comprises a voltage transformer, a high-voltage rectifier bridge and a current-limiting resistor which are connected in sequence; and the transfer branch is also connected in parallel with an energy consumption resistor controlled by a contactor. According to the utility model, the short-circuit current is quickly cut off by three branches, and the device has the advantages of simple principle, convenience in implementation, few components, high reliability, low cost and the like, and is suitable for a 10kV high-voltage direct-current power transmission system.

Description

TECHNICAL FIELD

[0001] The utility model relates to the high voltage direct current breaking technology field of electric power system, concretely relates to a high voltage direct current circuit breaker. BACKGROUND

[0002] With the rapid development of high voltage direct current transmission technology, the breaking capacity, reliability and high life of high voltage direct current circuit breaker are required very high. At present, the high voltage direct current circuit breaker that has implementation research and pilot, according to the different topological structure, is mainly divided into solid state type, mixed type and mechanical type three. Solid state type direct current circuit breaker main through branch selects power electronic device, breaking speed is extremely fast, can reach microsecond level, but on-state loss is high, accounts for 30% of the transmission power in commutation station, needs to increase water cooling heat dissipation device when the rated current is larger, and cost is higher, limits the engineering application thereof. The transfer branch of mixed type direct current circuit breaker selects power electronic device, and breaking speed is faster than mechanical type direct current circuit breaker, but needs to use a large number of devices series, parallel connection when the rated voltage and rated breaking current are higher, and the main through branch of partial topological also contains power electronic switch, and the structure is complex, and the cost is expensive. The main through branch of traditional mechanical type direct current circuit breaker is mechanical switch, and on-state loss is extremely low, and the transfer branch selects resonance capacitor and resonance inductor, and the cost is relatively low, but breaking speed is slow, and the breaking time, breaking current, cost and other factors should be considered comprehensively when designing to select;In the transfer branch, the scheme of high voltage ball extinguishing switch is used, but it will produce spark during conduction, which threatens the insulation equipment in the switch cabinet, and the reliability is low, and it has not been formally put into application. CONTENT OF THE UTILITY MODEL

[0003] The utility model provides a kind of high voltage direct current circuit breaker to solve the problems mentioned in the above background technology.

[0004] To achieve the above object, the utility model provides the following technical scheme: provide a kind of 10kV high voltage direct current circuit breaker with fast breaking speed, high reliability, compact structure and strong anti-interference ability.

[0005] The technical scheme of the application is: a kind of high voltage direct current circuit breaker, which belongs to a kind of mechanical type direct current circuit breaker, adopts the scheme of artificial zero, and includes main through branch, transfer branch and voltage limiting energy dissipation branch.

[0006] It includes main through branch, transfer branch and voltage limiting energy dissipation branch.

[0007] The main through branch includes a series-connected fast circuit breaker and a Hall current sensor, and the fast circuit breaker adopts a vortex repulsion mechanism.

[0008] The transfer branch is connected in parallel at both ends of the main current flow branch, comprising a high-voltage capacitor and an inductor connected in series, the high-voltage capacitor is connected to a charging power supply through a charging circuit, and the inductor is connected to the main current flow branch through a vacuum trigger tube; the charging circuit comprises a voltage transformer, a high-voltage rectifier bridge and a current limiting resistor connected in series; the transfer branch is also connected in parallel with an energy consumption resistor controlled by a contactor;

[0009] The voltage limiting energy consumption branch is connected in parallel at both ends of the main current flow branch, and a zinc oxide lightning arrester is arranged on the voltage limiting energy consumption branch.

[0010] It also comprises a fast controller connected with the Hall current sensor, the fast circuit breaker, the charging power supply, the high-voltage trigger power supply and the contactor, respectively, for controlling the coordinated action of each component.

[0011] Preferably, the breaking time of the fast circuit breaker is not more than 2 milliseconds, and the arc current generated when the fast circuit breaker is broken is superimposed with the high-frequency oscillation current generated by the high-voltage capacitor and the inductor to form an artificial current zero point.

[0012] Preferably, the high-voltage trigger power supply is connected with the vacuum trigger tube, adopts a floating potential design, and receives the trigger signal of the fast controller through an optical fiber.

[0013] Preferably, the charging power supply is connected through the secondary side of the voltage transformer, and charges the high-voltage capacitor after rectification by the high-voltage rectifier bridge.

[0014] Preferably, the zinc oxide lightning arrester is a zinc oxide valve.

[0015] Preferably, the high-voltage capacitor adopts a parallel structure of multiple capacitors, and the capacity thereof is adjustable according to the size of the short-circuit current.

[0016] Preferably, the inductor is realized by an equivalent inductor connected with a copper bar.

[0017] Preferably, the fast controller performs the following control timing in sequence when detecting a short-circuit fault:

[0018] First, control the fast circuit breaker to break;

[0019] After a delay of 2 ms, control the high-voltage trigger power supply to trigger the vacuum trigger tube to conduct;

[0020] After the fault is cleared, control the fast circuit breaker to close, and control the charging power supply to charge the high-voltage capacitor.

[0021] Preferably, the contactor is closed in the maintenance state to make the high-voltage capacitor discharge through the energy consumption resistor.

[0022] Preferably, the vacuum trigger tube is automatically turned off when the energy of the high-voltage capacitor is lower than the threshold value for maintaining conduction.

[0023] Compared with the prior art, the beneficial effects of this utility model are:

[0024] 1) Fast breaking speed: Fast circuit breakers have a fast response speed and can achieve precise breaking at any time, effectively limiting the rise of short-circuit current.

[0025] 2) High reliability: The vacuum trigger tube and vacuum interrupter have high reliability and long service life, making them suitable for frequent operation.

[0026] 3) Low energy consumption: Non-electric electronic type, with less energy consumption.

[0027] 4) Strong anti-interference capability: The trigger power supply adopts an equipotential design, and the signal transmission uses optical fiber, which effectively avoids electromagnetic interference and insulation problems.

[0028] 5) Low cost: Compared with traditional solutions, this solution is simple in principle and has a lower cost. Attached Figure Description

[0029] Figure 1 The diagram shown is a topology diagram of a high-voltage DC circuit breaker according to a specific embodiment of the present invention. Detailed Implementation

[0030] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0031] Please see Figure 1 This utility model provides the following technical solutions: such as Figure 1 As shown, this utility model embodiment provides a high-voltage DC circuit breaker, including a main current-carrying branch, a transfer branch, and a voltage-limiting and energy-dissipating branch;

[0032] The main current-carrying branch includes a fast circuit breaker CB and a Hall current sensor TA connected in series. The fast circuit breaker adopts an eddy current repulsion mechanism.

[0033] The transfer branch is connected in parallel across the main current-carrying branch and includes a high-voltage capacitor C and an inductor L connected in series. The high-voltage capacitor C is connected to the charging power supply through the charging circuit, and the inductor L is connected to the main current-carrying branch through the vacuum trigger tube TVS. The charging circuit includes a voltage transformer PT, a high-voltage rectifier bridge D, and a current-limiting resistor R1 connected in series. The transfer branch also has a power-consuming resistor R2 controlled by the contactor JCQ connected in parallel.

[0034] The voltage limiting and energy dissipation branch is connected in parallel to both ends of the main current-carrying branch, and a zinc oxide surge arrester (MOV) is installed on the voltage limiting and energy dissipation branch;

[0035] It also includes a fast controller, which is connected to the Hall current sensor TA, fast circuit breaker CB, charging power supply, high voltage trigger power supply and contactor JCQ respectively, to control the coordinated operation of each component.

[0036] The opening time of the fast circuit breaker CB is no more than 2 milliseconds. The arc current generated during its opening is superimposed with the high-frequency oscillating current generated by the high-voltage capacitor C and the inductor L to form an artificial current zero point.

[0037] The high-voltage trigger power supply is connected to the vacuum trigger tube TVS, adopts a floating potential design, and receives the trigger signal from the fast controller through optical fiber.

[0038] The charging power supply is controlled by the secondary side of the voltage transformer PT, and after rectification by the high-voltage rectifier bridge D, it charges the high-voltage capacitor C.

[0039] The high-voltage capacitor C adopts a parallel structure of multiple capacitors, and its capacity can be adjusted according to the short-circuit current.

[0040] The inductance L is achieved by the equivalent inductance of the connecting copper busbar.

[0041] When a short-circuit fault is detected, the fast controller executes the following control timing sequence in sequence:

[0042] First, control the fast circuit breaker CB to trip;

[0043] After a 2ms delay, the high-voltage trigger power supply is controlled to trigger the vacuum trigger tube TVS to conduct.

[0044] After the fault is cleared, the fast circuit breaker CB is closed, and the charging power supply is used to charge the high-voltage capacitor C.

[0045] When contactor JCQ is closed under maintenance, the high-voltage capacitor C discharges through the energy-consuming resistor R2.

[0046] The vacuum trigger tube TVS automatically turns off when the energy of the high-voltage capacitor C is lower than the conduction maintenance threshold.

[0047] Specifically, this high-voltage DC circuit breaker is a type of mechanical DC circuit breaker that uses a manual zeroing scheme, including a main current-carrying branch, a transfer branch, and a voltage-limiting and energy-consuming branch.

[0048] Main current-carrying branch: includes Hall current sensor TA and fast circuit breaker CB; the fast circuit breaker adopts a fast circuit breaker with eddy current repulsion mechanism to achieve stable and fast tripping within 2 milliseconds, effectively limiting the rise of short-circuit current.

[0049] Transfer branch: including high-voltage capacitor C, inductor L, charging power supply, voltage transformer PT, current limiting resistor R1, energy dissipation resistor R2, contactor JCQ, high-voltage rectifier bridge D, vacuum trigger tube TVS, high-voltage trigger power supply, fast controller.

[0050] Wherein, the fast controller is used for real-time monitoring of line state, controlling the action of the vacuum trigger tube of the fast circuit breaker, the charging power supply and the contactor; after the charging power supply receives the charging instruction of the fast controller, the secondary of the voltage transformer PT is connected, after the voltage transformer PT is boosted, the primary passes through the high-voltage rectifier bridge D to output direct current to charge the high-voltage capacitor C, in order to reduce the charging current, the high-voltage current limiting resistor R1 is connected in series; in order to facilitate maintenance, the high-voltage capacitor C is connected in parallel with the energy dissipation resistor R2, and is controlled by the contactor JCQ to close and open; the high-voltage trigger power supply adopts a floating potential and is not grounded, receives the trigger signal of the fast controller through the optical fiber module, and provides trigger energy for the vacuum trigger tube; the high-voltage capacitor C and the inductor L output a high-frequency oscillation current which is superimposed with the arc current when the main through-flow circuit is opened to realize artificial zero to extinguish the arc.

[0051] Voltage limiting and energy dissipation branch: a loop formed by a zinc oxide arrester, which limits overvoltage and dissipates capacitor energy, the voltage limiting and energy dissipation branch is mainly used for limiting overvoltage of the limiting value system and absorbing the residual current of the transfer branch, and the energy dissipation branch is composed of zinc oxide valve plates connected in series and parallel.

[0052] The specific short-circuit fault action control timing sequence is as follows:

[0053] 1) When a short-circuit current occurs on the 10kV bus, the Hall current sensor TA detects the fault current and transmits the current signal to the fast controller, the fast controller sends an opening instruction to the fast circuit breaker CB, the contacts of the fast circuit breaker are separated within 2ms, and the arc between the moving and static contacts starts to burn; because it is in a high-voltage direct-current system, the current does not pass through zero, and the arc cannot be extinguished.

[0054] 2) The fast controller sends an opening instruction to the high-voltage trigger power supply 2ms after sending the instruction to the fast circuit breaker CB, the high-voltage trigger power supply receives the closing instruction and sends a high-voltage trigger signal to the vacuum trigger tube TVS, and the vacuum trigger tube TVS is turned on; the high-voltage capacitor C pre-charged, the inductor L and the fast circuit breaker CB form a high-frequency oscillation current, the high-frequency oscillation current and the arc current of the fast circuit breaker CB are superimposed to generate an artificial current zero point, the arc of the fast circuit breaker CB is extinguished, and a vacuum gap insulation is formed.

[0055] 3) After the main through-flow branch short-circuit current is removed, the short-circuit current is transferred to the transfer branch to form resonance to generate overvoltage, when the overvoltage value is greater than the starting voltage of the zinc oxide arrester MOV, the zinc oxide arrester MOV is turned on to limit the overvoltage, and part of the energy of the high-voltage capacitor C is consumed.

[0056] 4) When the overvoltage generated by the high-voltage capacitor C and the DC system oscillation is less than the starting voltage of the zinc oxide surge arrester MOV, the zinc oxide surge arrester MOV stops absorbing energy; when the energy generated by the charging and discharging of the high-voltage capacitor C is insufficient to maintain the conduction energy of the vacuum trigger tube TVS, the vacuum trigger tube TVS current zero extinguishes, at which time the entire short-circuit fault current is cut off.

[0057] 5) When maintenance is required, the fast controller sends a closing instruction to the contactor JCQ, and the capacitor C releases residual charge under the action of the high-voltage resistor R2, preventing the operator from being electrified; after maintenance, the contactor JCQ is in the split position during normal operation.

[0058] 6) When the short-circuit fault is eliminated, the fast controller sends a closing instruction to the fast circuit breaker CB, and the main through-flow circuit is connected; at the same time, the fast intelligent controller sends a charging instruction to the charging power supply to charge the high-voltage capacitor C, preparing for the next short-circuit fault processing.

[0059] In more detail, in the embodiment:

[0060] The selected fast circuit breaker CB adopts a vortex repulsive force mechanism, which has a short opening time, small dispersion, high controllability, and strong stability when cooperating with the fast intelligent controller.

[0061] The selected zinc oxide surge arrester MOV is a zinc oxide valve, which is configured in series and parallel according to the size of the overvoltage and the short-circuit current.

[0062] The selected high-voltage capacitor C can be configured in multiple parallel modes according to the size of the short-circuit current.

[0063] The selected inductor L is configured according to the size of the short-circuit current, which can be directly equivalent to a primary copper bar and does not need to be separately wound.

[0064] In general, the high-voltage DC circuit breaker provided by the utility model adopts the artificial zero method to forcibly form a current zero point arc extinction of the DC current; has the advantages of simple principle, low power consumption, clear control logic, fast short-circuit fault current processing, high reliability, etc.

[0065] Although the embodiments of the utility model have been shown and described, it can be understood by those skilled in the art that various changes, modifications, replacements and variations can be made to these embodiments without departing from the principles and spirits of the utility model, and the scope of the utility model is defined by the appended claims and their equivalents.

Claims

1. A high-voltage DC circuit breaker, characterized in that, This includes main flow branches, transfer branches, and pressure-limiting energy-consuming branches; The main current-carrying branch includes a fast circuit breaker and a Hall current sensor connected in series, and the fast circuit breaker adopts an eddy current repulsion mechanism. The transfer branch is connected in parallel across the main current-carrying branch and includes a high-voltage capacitor and an inductor connected in series. The high-voltage capacitor is connected to a charging power supply through a charging circuit, and the inductor is connected to the main current-carrying branch through a vacuum trigger tube. The charging circuit includes a voltage transformer, a high-voltage rectifier bridge, and a current-limiting resistor connected in series. The transfer branch also has a power-dissipating resistor controlled by a contactor connected in parallel. The voltage limiting and energy dissipation branch is connected in parallel to both ends of the main current-carrying branch, and a zinc oxide surge arrester is installed on the voltage limiting and energy dissipation branch; It also includes a fast controller, which is connected to the Hall current sensor, fast circuit breaker, charging power supply, high voltage trigger power supply and contactor respectively, to control the coordinated operation of each component.

2. The high-voltage DC circuit breaker according to claim 1, characterized in that, The opening time of the fast circuit breaker is no more than 2 milliseconds. The arc current generated during its opening is superimposed with the high-frequency oscillating current generated by the high-voltage capacitor and inductor to form an artificial current zero point.

3. The high-voltage DC circuit breaker according to claim 1, characterized in that, The high-voltage trigger power supply is connected to the vacuum trigger tube, adopts a floating potential design, and receives the trigger signal from the fast controller through an optical fiber.

4. The high-voltage DC circuit breaker according to claim 1, characterized in that, The charging power supply is controlled by the secondary side of the voltage transformer, and after rectification by the high-voltage rectifier bridge, it charges the high-voltage capacitor.

5. The high-voltage DC circuit breaker according to claim 1, characterized in that, The zinc oxide surge arrester is a zinc oxide valve plate.

6. The high-voltage DC circuit breaker according to claim 1, characterized in that, The high-voltage capacitor adopts a parallel structure of multiple capacitors, and its capacity can be adjusted according to the magnitude of the short-circuit current.

7. The high-voltage DC circuit breaker according to claim 1, characterized in that, The inductance is achieved by the equivalent inductance of the connecting copper busbar.

8. The high-voltage DC circuit breaker according to claim 1, characterized in that, When a short-circuit fault is detected, the fast controller executes the following control timing sequence in sequence: First, control the fast circuit breaker to trip; After a 2ms delay, the high-voltage trigger power supply is controlled to trigger the vacuum trigger tube to conduct. After the fault is cleared, the fast circuit breaker is closed and the charging power supply is used to charge the high-voltage capacitor.

9. The high-voltage DC circuit breaker according to claim 1, characterized in that, When the contactor is under maintenance, it closes, allowing the high-voltage capacitor to discharge through the energy-consuming resistor.

10. The high-voltage DC circuit breaker according to any one of claims 1-9, characterized in that, The vacuum trigger tube automatically turns off when the energy of the high-voltage capacitor is lower than the conduction maintenance threshold.

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