Current cut-off device for high-voltage DC path
By designing a circuit topology configured using the AC switch device in the DC network, the problem of complexity of DC current interruption is solved, and effective current interruption for various faults is achieved.
Patent Information
- Application Number
- CN202411088315.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2023-08-11
- Filing Date
- 2024-08-09
- Publication Date
- 2025-02-18
AI Technical Summary
In a DC network, the current does not naturally cross zero, resulting in complex current injection methods and difficult to synchronize and control, making it difficult to effectively interrupt DC current.
A circuit topology is designed to interrupt current in the DC network using an AC switch device configuration, including connecting capacitor banks, inductors and mechanical circuit breakers in parallel in the first high voltage DC path, and responding to fault current through the second mechanical circuit breaker Close the auxiliary branch to generate superimposed current and generate current zero crossing in the main branch.
The current interruption capability of the pole-to-pole fault and the pole-to-ground fault with low ohmic and high ohmic grounding is achieved, simplifying the device structure and improving control synchronization.
Smart Images
Figure CN119482303A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to medium voltage direct current (DC) power distribution systems, and more particularly to circuits and methods for interrupting current flow in a direct current (DC) path. Background Art
[0002] HVDC transmission is an interesting solution for reducing overall network losses and integrating renewable energy sources such as wind or photovoltaic power. Like conventional AC networks, DC networks require protection against short circuits by current-interrupting devices, so-called circuit breakers.
[0003] In AC networks, the zero-crossing event of the current is used to extinguish the arc generated when the circuit is opened and to actually interrupt the current. A typical difficulty in operating a DC circuit breaker is that the current does not naturally cross zero.
[0004] In order to produce a zero-crossing event of the DC current, a method generally known as current injection was developed. According to this method, an oscillating circuit including a capacitor and an inductor is connected in parallel to the main path of the circuit breaker, and the current oscillations in the parallel circuit are superimposed on the DC current in the main path of the circuit breaker. The resulting current combination oscillates around zero, allowing the current to be interrupted.
[0005] Different solutions have been proposed for current injection. These solutions usually involve various switches to charge and discharge the oscillating circuit. These switches can be difficult to synchronize and control, resulting in a complex device.
[0006] The DC network may be part of a hybrid AC / DC network. The type of protection may depend on the type of earthing chosen for the neutral conductor of the hybrid AC / DC network.
[0007] The proposed solution improves the design of known solutions. It proposes a circuit topology that interrupts the current in the DC network using an AC switchgear configuration. The proposed solution handles both low-ohmic and high-ohmic grounding of the network. Summary of the invention
[0008] To this end, a current cutting device is proposed, comprising:
[0009] A first current cut-off device, for interrupting the flow of current in a first high-voltage direct current path between the first terminal and the second terminal, comprising:
[0010] a first main branch inserted in the first DC path, comprising a first mechanical circuit breaker, the first mechanical circuit breaker being normally closed,
[0011] - a first auxiliary branch connected in parallel to the first mechanical circuit breaker, comprising a series connection of a capacitor bank, an inductor and a second mechanical circuit breaker, called a first reversing switch, the second mechanical circuit breaker being normally open,
[0012] - surge arresters connected in parallel with the capacitor bank,
[0013] - a second auxiliary branch connecting the first intermediate terminal comprised between the capacitor bank and the inductor to a ground connection, the second auxiliary branch comprising a resistor,
[0014] The second mechanical circuit breaker is configured to close the first auxiliary branch in response to the occurrence of a fault current in the first main branch, thereby generating a current that is superimposed on the current flow in the first main branch and causes a current zero crossing in the first main branch.
[0015] This arrangement provides current interruption capability for pole-to-pole faults and pole-to-ground faults with low-ohmic ground and high-ohmic ground.
[0016] The following features may be implemented individually or in combination:
[0017] In an embodiment, the current cut-off device further comprises:
[0018] - a second current cut-off device, for interrupting the flow of current in a second high-voltage DC path between the third terminal and the fourth terminal, comprising:
[0019] a second main branch inserted in the second DC path, comprising a first mechanical circuit breaker, the first mechanical circuit breaker being normally closed,
[0020] - a first auxiliary branch connected in parallel with the first mechanical circuit breaker, comprising a series connection of a capacitor bank, an inductor and a second mechanical circuit breaker called a reversing switch, the second mechanical circuit breaker being normally open,
[0021] - surge arresters connected in parallel with the capacitor bank,
[0022] - a second auxiliary branch connecting the first intermediate terminal comprised between the capacitor bank and the inductor to a ground connection, the second auxiliary branch comprising a resistor,
[0023] The second mechanical circuit breaker is configured to close the first auxiliary branch in response to the occurrence of a fault current in the second main branch, thereby generating a current that is superimposed on the current flow in the second main branch and causes a current zero crossing in the second main branch.
[0024] This arrangement with a second current disconnecting device on the second DC path provides current interruption capability for pole-to-pole faults and pole-to-ground faults with low-ohmic grounding as well as pole-to-ground faults with high-ohmic grounding. Thus, for a given network grounding, a comprehensive protection in combination with the disconnecting device and its auxiliary branches is proposed.
[0025] According to one aspect of the current interruption device:
[0026] a first high voltage DC path connected to a first pole of the hybrid AC / DC network, and
[0027] The second high voltage DC path is connected to a second pole of the hybrid AC / DC network.
[0028] The first pole of the hybrid AC / DC network is the positive current supply pole.
[0029] The second pole of the hybrid AC / DC network is the negative current return pole.
[0030] In an embodiment of the current disconnect device, the first current disconnect means and the second current disconnect means are identical.
[0031] This configuration is particularly suitable for low-ohmic grounded networks. In a network with low-ohmic grounding, both the first current interruption device and the second current interruption device interrupt pole-to-pole faults and pole-to-ground faults.
[0032] In an alternative embodiment of the current interruption device:
[0033] - the capacitance of the capacitor bank of the first current-interruption device is different from the capacitance of the capacitor bank of the second current-interruption device, and / or
[0034] - the inductance of the inductor of the first current-interruption device is different from the inductance of the inductor of the second current-interruption device, and / or
[0035] The resistance of the resistor of the first current cut-off device is different from the resistance of the resistor of the second current cut-off device.
[0036] As a variant or in addition, the second mechanical circuit breaker of the first current disconnect device is different from the second mechanical circuit breaker of the second current disconnect device.
[0037] This configuration is particularly suitable for high-ohmic grounding networks. In networks with high-ohmic grounding, one current disconnecting device interrupts pole-to-pole faults and pole-to-earth faults, while the other current disconnecting device interrupts only pole-to-earth faults.
[0038] The first main branch and the second main branch are main conductors of the first current-cutoff device and the second current-cutoff device, respectively.
[0039] The first auxiliary branch of the first current-cutoff device and the first auxiliary branch of the second current-cutoff device are secondary conductive lines of the first current-cutoff device and the second current-cutoff device, respectively.
[0040] The second auxiliary branch of the first current cut-off device and the second auxiliary branch of the second current cut-off device are third conductive lines of the first current cut-off device and the second current cut-off device, respectively.
[0041] The first current disconnect device can operate in a first mode, referred to as a normal operating mode, in which the first mechanical circuit breaker of the first current disconnect device is in a closed state and the second mechanical circuit breaker of the first current disconnect device is in an open state.
[0042] The first current disconnect device may operate in a second mode, referred to as a fault mode, wherein the first mechanical circuit breaker of the first current disconnect device is in an open state and the second mechanical circuit breaker of the first current disconnect device is in a closed state.
[0043] In response to the occurrence of a fault current in the first main branch, the first current disconnect device may switch from the first mode to the second mode.
[0044] The first current disconnect device may also operate in a third mode, referred to as a residual current fault mode, in which the first mechanical circuit breaker is in an open state and the second mechanical circuit breaker is in an open state.
[0045] The first current interrupting device may switch from the second mode to the third mode in response to the presence of a residual fault current in the first auxiliary branch.
[0046] The first current disconnect device can operate in a fourth mode, referred to as a normal operating mode after fault interruption, in which the first mechanical circuit breaker is in a closed state and the second mechanical circuit breaker is in an open state.
[0047] After the capacitor bank is recharged by a current flowing from the source side to the resistor of the second auxiliary branch, the first current cut-off device may be switched from the third mode to the fourth mode.
[0048] The second current interrupt device operates in the same manner as the first current interrupt device.
[0049] Therefore, the second current disconnect device can be operated in a first mode, referred to as a normal operating mode, wherein the first mechanical circuit breaker of the second current disconnect device is in a closed state and the second mechanical circuit breaker of the second current disconnect device is in an open state.
[0050] The second current disconnect device is operable in a second mode, referred to as a fault mode, wherein the first mechanical circuit breaker of the second current disconnect device is in an open state and the second mechanical circuit breaker of the second current disconnect device is in a closed state.
[0051] In response to the occurrence of a fault current in the second main branch, the second current disconnect device may switch from the first mode to the second mode.
[0052] The second current disconnect device can also operate in a third mode, referred to as a residual current fault mode, in which the first mechanical circuit breaker is in an open state and the second mechanical circuit breaker is in an open state.
[0053] In response to the presence of a residual fault current in the first auxiliary branch, the second current cut-off device may switch from the second mode to the third mode.
[0054] The second current disconnect device may operate in a fourth mode, referred to as a normal operation mode after fault interruption, in which the first mechanical circuit breaker is in a closed state and the second mechanical circuit breaker is in an open state.
[0055] After the capacitor bank is recharged by the current flowing from the source side to the resistor of the second auxiliary branch, the second current cut-off device may be switched from the third mode to the fourth mode.
[0056] The inductance of the inductor of the first current cut-off device is between 10 µH and 1 mH.
[0057] The capacitance of the capacitor bank of the first current cut-off device is between 3 µF and 300 µF.
[0058] The resistance of the resistor of the first current cut-off device is higher than 1000 ohms.
[0059] The ratio of the pole-to-ground voltage to the resistance of the first current interruption device is lower than 2A.
[0060] The product of the inductance and capacitance of the first current interruption device is 3.10 -11 s 2 and 3.10 -7 s 2 between.
[0061] The surge arrester of the first current interruption device is selected to conduct a current of less than 10 A when subjected to a pole-to-ground voltage.
[0062] The inductance of the inductor of the second current cut-off device is between 10µH and 1 mH.
[0063] The capacitance of the capacitor bank of the second current cut-off device is between 3 µF and 300 µF.
[0064] The resistance of the resistor of the second current cut-off device is higher than 1000 ohms.
[0065] The ratio of the pole-to-ground voltage to the resistance of the second current interruption device is lower than 2A.
[0066] The product of the inductance and capacitance of the second current interruption device is 3.10 -11 s 2 and 3.10 -7 s 2 between.
[0067] The surge arrester of the second current interruption device is selected to conduct a current less than 10 A when subjected to a pole-to-earth voltage.
[0068] In an embodiment, the first current cut-off device further comprises a first switch device, which is arranged on the first auxiliary branch between the inductor and the second connection of the first auxiliary branch and the first main branch.
[0069] The first switching device of the first current disconnecting device may be arranged on the first auxiliary branch between the second mechanical circuit breaker and the second connection of the first auxiliary branch with the first main branch.
[0070] In an embodiment, the second current cut-off device further comprises a first switch device, which is arranged on the first auxiliary branch between the inductor and the second connection of the first auxiliary branch and the second main branch.
[0071] The first switching device of the second current disconnecting device may be arranged on the first auxiliary branch between the second mechanical circuit breaker and the second connection of the first auxiliary branch and the second main branch.
[0072] In an embodiment, the first switching device of the first current disconnect device may be identical to the first switching device of the second current disconnect device.
[0073] In a variant, the first switching device of the first current disconnect device may be different from the first switching device of the second current disconnect device.
[0074] In an embodiment of the current disconnection device, the first current disconnection means further comprises a third switching device, which is arranged on the first main branch between the first terminal and the first connection of the first auxiliary branch and the first main branch.
[0075] In an embodiment of the current disconnection device, the second current disconnection means further comprises a third switching device arranged on the second main branch, between the third terminal and the first connection of the first auxiliary branch and the second main branch.
[0076] According to an embodiment of the current disconnection device, the first current disconnection device further comprises a second switching device arranged on the first main branch between a first connection of the first auxiliary branch to the first main branch and a second connection of the first auxiliary branch to the first main branch.
[0077] According to an embodiment of the current disconnection device, the second current disconnection device further comprises a second switching device arranged on the second main branch between a first connection of the first auxiliary branch to the second main branch and a second connection of the first auxiliary branch to the second main branch.
[0078] Each switching device can be a two-position disconnector, or a three-position disconnector. A two-position disconnector has only two stable positions: the first position, called the closed position, in which the movable contact is in contact with the fixed contact, allowing the current to flow; the second position, called the open position, in which the movable contact is separated from the fixed contact, interrupting the current flow. This type of disconnector is also called an isolator switch. A three-position disconnector has three stable positions: the two positions already mentioned, plus a third position in which the movable contact is grounded. This type of disconnector is also called an earthing switch.
[0079] In an embodiment of the current interruption device:
[0080] a first mechanical circuit breaker of the first current disconnecting device, a second mechanical circuit breaker of the first current disconnecting device, a second switching device of the first current disconnecting device, and
[0081] The first mechanical circuit breaker of the second current disconnecting device, the second mechanical circuit breaker of the second current disconnecting device, and the second switchgear of the second current disconnecting device are arranged in the gas-insulated box.
[0082] The integration of different mechanical circuit breakers in a common gas-insulated box provides electrical insulation characteristics and environmental sensitivity, making the solution robust and reliable. In addition, when the first mechanical circuit breaker and the second mechanical circuit breaker of the two current interruption devices are arranged in the same gas-insulated box, the synchronization of their operations becomes easier. This simplifies installation and future maintenance.
[0083] In another embodiment of the current interruption device:
[0084] a first mechanical circuit breaker of the first current disconnecting device, a second mechanical circuit breaker of the first current disconnecting device, a first switching device of the first current disconnecting device, a second switching device of the first current disconnecting device, a third switching device of the first current disconnecting device, and
[0085] The first mechanical circuit breaker of the second current disconnecting device, the second mechanical circuit breaker of the second current disconnecting device, the first switching device of the second current disconnecting device, the second switching device of the second current disconnecting device, and the third switching device of the second current disconnecting device are arranged in the gas insulation box.
[0086] The integration of different mechanical circuit breakers and earthing switches further allows for a more compact design.
[0087] In an embodiment, the capacitor bank, the inductor, the resistor and the surge arrester of the first current cutoff device are arranged in the first metal enclosed compartment.
[0088] In an embodiment, the capacitor bank, the inductor, the resistor and the surge arrester of the second current cutoff device are arranged in the second metal enclosed compartment.
[0089] The assembly of the current interruption device is easier when the capacitor bank, inductor, resistor and surge arrester form a pre-assembled module.
[0090] In an embodiment, the capacitor bank, inductor, resistor, surge arrester of the first current cut-off device and the capacitor bank, inductor, resistor and surge arrester of the second current cut-off device are arranged in a common metal enclosed compartment. BRIEF DESCRIPTION OF THE DRAWINGS
[0091] Other features, details and advantages will appear from the following detailed description and the accompanying drawings, in which:
[0092] Figure 1 is a schematic diagram of a hybrid AC / DC grid protected by a current cut-off device.
[0093] Figure 2 is a schematic diagram of an embodiment of the proposed current interruption device,
[0094] Figure 3 yes Figure 2 A variation of the embodiment,
[0095] Figure 4 yes Figure 3 Variations of the embodiments. DETAILED DESCRIPTION
[0096] For ease of reading, various elements are not necessarily drawn to scale. In these figures, identical elements receive identical reference numerals. Certain elements or parameters may be indexed, that is to say specified by, for example, "first element" or "second element", or first parameter and second parameter, etc. The purpose of such indexing is to distinguish between similar but not identical elements or parameters. Such indexing does not mean that one element or one parameter takes precedence over another, and their names are interchangeable. When referring to a subsystem including a given element, it is not excluded that other elements exist in the subsystem.
[0097] Figure 1 A hybrid high voltage AC / DC network 50 is schematically illustrated. The DC portion of the network includes a positive pole and a negative pole. A current cut-off device 20 protects the DC portion of the network. A direct current (DC) source is connected between the T1 and T3 terminals. An electrical load is connected between the T2 and T4 terminals. By definition and in the context of the present disclosure, a source is an electrical node that provides electrical power. In contrast, an electrical load is an electrical node that consumes electrical energy.
[0098] Figure 2 Shown is a current interruption device 20 comprising:
[0099] - A first current cut-off device 21, for interrupting the current flow in the first high-voltage DC path between the first terminal T1 and the second terminal T2, comprising:
[0100] a first main branch A-1 inserted in a first DC path, comprising a first mechanical circuit breaker CB1-1, the first mechanical circuit breaker CB1-1 being normally closed,
[0101] a first auxiliary branch B-1 connected in parallel to a first mechanical circuit breaker CB1-1, comprising a series connection of a capacitor bank CA-1, an inductor L-1 and a second mechanical circuit breaker CB2-1, called a first reversing switch, the second mechanical circuit breaker CB2-1 being normally open,
[0102] - a surge arrester SA-1 connected in parallel with the capacitor bank CA-1,
[0103] - a second auxiliary branch C- 1 connecting the first intermediate terminal I1 - 1 comprised between the capacitor bank CA- 1 and the inductor L- 1 to the ground connection EC- 1 , the second auxiliary branch C- 1 comprising a resistor R- 1 .
[0104] The second mechanical circuit breaker CB2-1 is configured to close the first auxiliary branch B-1 in response to the occurrence of a fault current in the first main branch A-1 so as to generate a current superimposed on the current flow in the first main branch A-1 and to generate a current zero crossing in the first main branch A-1.
[0105] The arrangement provides current interruption capability for pole-to-pole faults and pole-to-ground faults with low-ohmic ground and high-ohmic ground.
[0106] The current cut-off device 20 also includes:
[0107] - a second current cut-off device 22, for interrupting the current flow in the second high-voltage DC path between the third terminal T3 and the fourth terminal T4, comprising:
[0108] a second main branch A-2 inserted in the second DC path, comprising a first mechanical circuit breaker CB1-2, the first mechanical circuit breaker CB1-2 being normally closed,
[0109] a first auxiliary branch B-2 connected in parallel to the first mechanical circuit breaker CB1-2, comprising a series connection of a capacitor bank CA-2, an inductor L-2 and a second mechanical circuit breaker CB2-2, called a reversing switch, the second mechanical circuit breaker CB2-2 being normally open,
[0110] - a surge arrester SA-2 connected in parallel with the capacitor bank CA-2,
[0111] A second auxiliary branch C-2 connecting the first intermediate terminal I1-2 comprised between the capacitor bank CA-2 and the inductance L-2 to the ground connection EC-2, the second auxiliary branch C-2 comprising a resistor R-2.
[0112] The second mechanical circuit breaker CB2-2 is configured to close the first auxiliary branch B-2 in response to the occurrence of a fault current in the second main branch A-2 so as to generate a current superimposed on the current flow in the second main branch A-2 and to generate a current zero crossing in the second main branch A-2.
[0113] This arrangement with the second current interruption device on the second DC path provides current interruption capability for pole-to-pole faults and pole-to-ground faults with low-ohmic grounding and pole-to-ground faults with high-ohmic grounding. Thus, a comprehensive protection of the high voltage DC network is proposed.
[0114] The first high voltage direct current path is connected to a first pole of the hybrid AC / DC network. The first pole of the hybrid AC / DC network is here a positive current supply pole.
[0115] The second high voltage DC path is connected to a second pole of the hybrid AC / DC network. The second pole of the hybrid AC / DC network is a negative current return pole.
[0116] The first current interruption device 21 and the second current interruption device 22 have the same structure.
[0117] In an embodiment of the current disconnect device 20 , the first current disconnect device 21 and the second current disconnect device 22 are identical.
[0118] In this case, the first current cutoff device 21 and the second current cutoff device 22 have the same structure and the same characteristics for the inductors L-1, L-2, the capacitor banks CA-1, CA-2, the resistors R-1, R-2 and the surge arresters SA-1, SA-2.
[0119] This configuration is particularly suitable for low-ohmic grounding networks. In a network with low-ohmic grounding, both the first current disconnection device and the second current disconnection device disconnect pole-to-pole faults and pole-to-ground faults.
[0120] In an alternative embodiment of the current interrupt device 20:
[0121] - the capacitance of the capacitor bank CA-1 of the first current interruption device 21 is different from the capacitance of the capacitor bank CA-2 of the second current interruption device 22, and / or
[0122] - the inductance of the inductor L-1 of the first current interruption device 21 is different from the inductance of the inductor L-2 of the second current interruption device 22, and / or
[0123] The resistance of the resistor R- 1 of the first current-cut device 21 is different from the resistance of the resistor R- 2 of the second current-cut device 22 .
[0124] In other words, the first current cut-off device 21 and the second current cut-off device 22 have the same structure, but are not identical because the characteristics of one or more of their respective inductors L-1, L-2, capacitor groups CA-1, CA-2, resistors R-1, R-2 and surge arresters SA-1, SA-2 are different.
[0125] This configuration is particularly suitable for high-ohmic grounding networks. In networks with high-ohmic grounding, one current disconnecting device interrupts pole-to-pole faults and pole-to-earth faults, while the other current disconnecting device interrupts only pole-to-earth faults.
[0126] The second mechanical circuit breaker CB2 - 1 of the first current break device 21 may be different from the second mechanical circuit breaker CB2 - 2 of the second current break device 22 .
[0127] The first main branch A- 1 and the second main branch A- 2 are main conductors of the first current interruption device 21 and the second current interruption device 22 , respectively.
[0128] The first auxiliary branch B- 1 of the first current-cutoff device 21 and the first auxiliary branch B- 2 of the second current-cutoff device 22 are secondary conductive lines of the first current-cutoff device 21 and the second current-cutoff device 22 , respectively.
[0129] The second auxiliary branch C- 1 of the first current cut-off device 21 and the second auxiliary branch C- 2 of the second current cut-off device 22 are third conductive lines of the first current cut-off device 21 and the second current cut-off device 22 , respectively.
[0130] The first current disconnect device 21 can operate in a first mode, referred to as a normal operating mode, in which the first mechanical circuit breaker CB1-1 of the first current disconnect device 21 is closed and the second mechanical circuit breaker CB2-1 of the first current disconnect device 21 is open. Figure 2 and Figure 3 The mode shown.
[0131] The first current disconnect device 21 can operate in a second mode, called fault mode, in which the first mechanical circuit breaker CB1-1 of the first current disconnect device 21 is open and the second mechanical circuit breaker CB2-1 of the first current disconnect device 21 is closed. This operating mode is not yet shown.
[0132] The first current interruption device 21 may switch from the first mode to the second mode in response to the occurrence of a fault current in the first main branch A-1. The occurrence of the fault current may be the result of a pole-to-pole short circuit or a pole-to-ground short circuit.
[0133] When a fault current appears in the first main branch A-1 of the first current disconnecting device 21, the closing of the second mechanical circuit breaker CB2-1 causes an oscillating current to be generated through the first auxiliary branch B-1, which is superimposed on the current flow in the first main branch A-1. The amplitude of the oscillation generates a zero-crossing event of the current in the first main branch A-1, which makes it possible to interrupt the current in the first main branch A-1 through the first mechanical circuit breaker CB1-1 of the first current disconnecting device 21.
[0134] The first current disconnect device 21 can also operate in a third mode, referred to as a residual current fault mode, in which the first mechanical circuit breaker CB1 - 1 is in an open state and the second mechanical circuit breaker CB2 - 1 is in an open state.
[0135] The first current cut-off device 21 may switch from the second mode to the third mode in response to a residual fault current occurring in the first auxiliary branch B- 1 .
[0136] The first current disconnect device 21 can operate in a fourth mode, referred to as a normal operation mode after fault interruption, in which the first mechanical circuit breaker CB1-1 is in a closed state and the second mechanical circuit breaker CB2-1 is in an open state.
[0137] After the capacitor bank CA- 1 is recharged by the current flowing from the source side to the resistor R- 1 of the second auxiliary branch C- 1 , the first current cut-off device 21 may be switched from the third mode to the fourth mode.
[0138] Likewise, the second current disconnect device 22 may operate in a first mode, referred to as a normal operating mode, wherein the first mechanical circuit breaker CB1 - 2 of the second current disconnect device 22 is closed and the second mechanical circuit breaker CB2 - 2 of the second current disconnect device 22 is open.
[0139] The second current disconnect device 22 may operate in a second mode referred to as a fault mode, in which the first mechanical circuit breaker CB1 - 2 of the second current disconnect device 22 is open and the second mechanical circuit breaker CB2 - 2 of the second current disconnect device 22 is closed.
[0140] The second current cut-off device 22 can switch from the first mode to the second mode in response to the occurrence of a fault current in the second main branch A2.
[0141] The second current cut-off device 22 can also operate in a third mode, called a residual current fault mode, in which the first mechanical circuit breaker CB1-2 is in an open state and the second mechanical circuit breaker CB2-2 is in an open state. In response to the presence of a residual fault current in the first auxiliary branch B-2, the second current cut-off device 22 can switch from the second mode to the third mode. The second current cut-off device 22 can also operate in a fourth mode, called a normal operation mode after fault interruption, in which the first mechanical circuit breaker CB1-2 is in a closed state and the second mechanical circuit breaker CB2-2 is in an open state. After the capacitor bank CA-2 is recharged by the current flowing from the source side to the resistor R-2 of the second auxiliary branch C-2, the second current cut-off device 22 can switch from the third mode to the fourth mode.
[0142] As with the first current interrupting device 21 , the occurrence of a fault current in the second current interrupting device 22 may be the result of a pole-to-pole short circuit or a pole-to-ground short circuit.
[0143] The second current disconnecting device 22 operates in the same manner as the first current disconnecting device 21. When a fault current appears in the first main branch A-2 of the second current disconnecting device 22, the closing of the second mechanical circuit breaker CB2-2 causes the generation of an oscillating current through the first auxiliary branch B-2, which is superimposed on the current flow in the second main branch A-2. The amplitude of the oscillation generates a zero-crossing event of the current in the second main branch A-2, which makes it possible for the current in the second main branch A-2 to be interrupted by the first mechanical circuit breaker CB1-2 of the second current disconnecting device 22.
[0144] Each of the first mechanical circuit breakers CB1-1, CB1-2 and the second mechanical circuit breakers CB2-1, CB2-2 may include a vacuum circuit breaker.
[0145] The inductance of the inductor L-1 of the first current interruption device 21 is between 10 µH and 1 mH. The capacitance of the capacitor bank CA-1 of the first current interruption device 21 is between 3 µF and 300 µF. The resistance of the resistor R-1 of the first current interruption device 21 is higher than 1000 ohms.
[0146] The ratio of the pole-to-ground voltage to the resistance of the first current cut-off device 21 is lower than 2A. The product of the inductance and capacitance of the first current cut-off device 21 is between 3.10 -11 s 2 and 3.10 -7 s 2 between.
[0147] The surge arrester SA-1 of the first current interruption device 21 is selected to conduct a current less than 10 A when subjected to a pole-to-ground voltage.
[0148] The inductance of the inductor L-2 of the second current cut-off device 22 is between 10µH and 1 mH. The capacitance of the capacitor bank CA-2 of the second current cut-off device 22 is between 3µF and 300µF. The resistance of the resistor R-2 of the second current cut-off device 22 is higher than 1000 ohms.
[0149] The ratio of the pole-to-ground voltage to the resistance of the second current cut-off device 22 is lower than 2A. The product of the inductance and capacitance of the second current cut-off device 22 is between 3.10 and 1. -11 s 2 and 3.10 -7 s 2 between.
[0150] The surge arrester SA-2 of the second current interruption device 22 is selected to conduct a current less than 10A when subjected to a pole-to-ground voltage.
[0151] The first auxiliary branch B-1 of the first current disconnect device 21 includes a first connection N1-1 with the first main branch A-1 and a second connection N2-1 with the first main branch A-1. The first connection N1-1 of the first auxiliary branch B-1 of the first current disconnect device 21 to the first main branch A-1 of the first current disconnect device 21 is included between the first terminal T1 and the first terminal CB1-1a of the first mechanical circuit breaker CB1-1 of the first current disconnect device 21. The second connection N2-1 is included between the second terminal T2 and the second terminal CB1-1b of the first mechanical circuit breaker CB1-1 of the first current disconnect device 21.
[0152] Likewise, the first auxiliary branch B-2 of the second current disconnect device 22 includes a first connection N1-2 with the second main branch A-2 and a second connection N2-2 with the second main branch A-2. The first connection N1-2 of the second auxiliary branch B-2 of the second current disconnect device 22 and the second main branch A-2 of the second current disconnect device 22 is included between the third terminal T3 and the first terminal of the first mechanical circuit breaker CB1-2 of the second current disconnect device 22. The second connection N2-1 is included between the fourth terminal T4 and the second terminal of the first mechanical circuit breaker CB1-2 of the second current disconnect device 22.
[0153] The first terminal of the resistor R-1 is directly connected to ground, represented by the ground connection EC-1. The second terminal of the resistor R-1 is directly connected to the first terminal of the capacitor bank CA-1, referred to as the first intermediate terminal I1-1. The surge arrester SA-1 and the capacitor bank CA-1 are connected in parallel between the first intermediate terminal I1-1 and the first connection N1-1. In the schematic diagram, the first intermediate terminal I1-1 is also the first connection between the surge arrester SA-1 and the capacitor bank CA-1. The second intermediate terminal I1-2 represents the second connection between the surge arrester SA-1 and the capacitor bank CA-1. In the schematic diagram, the resistor R-1 and the surge arrester SA-1 are both connected to a common node of the capacitor bank CA-1. The connection nodes can also be staggered along the second auxiliary branch B-2. The first terminal of the inductor L-1 is directly connected to the first intermediate terminal I1-1. The second terminal of the inductor L-1 is connected to the first main branch A-1 via the second mechanical circuit breaker CB2-1. The arrangement of the electrical connections between the components of the second current cut-off device 22 is the same as that of the first current cut-off device 21. The resistor R-2 and the surge arrester SA-2 are connected in parallel between the nodes I2-1 and I2-2, and the resistor R2 is connected between the node I2-1 and the ground connection EC-2. The first current cut-off device 21 also includes a first switching device SD1-1, which is arranged on the first auxiliary branch B-1, between the inductor L-1 and the second connection N2-1 of the first auxiliary branch B-1 and the first main branch A-1. In the example shown, the first switching device SD1-1 of the first current cut-off device 21 is arranged on the first auxiliary branch B-1, between the second mechanical circuit breaker CB2-1 and the second connection N2-1 of the first auxiliary branch B-1 and the first main branch A-1.
[0154] The second current cut-off device 22 also includes a first switching device SD1-2, which is arranged on the first auxiliary branch B-2, between the inductor L2 and the second connection N2-2 of the first auxiliary branch B-2 and the second main branch A-2. In the example shown, the first switching device SD1-2 of the second current cut-off device 22 can be arranged on the first auxiliary branch B-2, between the second mechanical circuit breaker CB2-2 and the second connection N2-2 of the first auxiliary branch B2 and the second main branch A2.
[0155] The first switching device SD1-1 of the first current cutoff device 21 may be identical to the first switching device SD1-2 of the second current cutoff device 22. Alternatively, the first switching device SD1-1 of the first current cutoff device 21 may be different from the first switching device SD1-2 of the second current cutoff device 22.
[0156] The first current cut-off device 21 further includes a second switch device SD2-1, which is arranged on the first main branch A-1 and is located between the first connection N1-1 between the first auxiliary branch B-1 and the first main branch A-1 and the second connection N2-1 between the first auxiliary branch B-1 and the first main branch A-1. In the same manner, the second current cut-off device 22 further includes a second switch device SD2-2, which is arranged on the second main branch A-2 and is located between the first connection N1-2 between the first auxiliary branch B-2 and the second main branch A-2 and the second connection N2-2 between the first auxiliary branch B-2 and the second main branch A-2.
[0157] The first current cut-off device 21 further includes a third switch device SD3-1, which is arranged on the first main branch A-1, between the first terminal T1 and the first connection N1-1 between the first auxiliary branch B-1 and the first main branch A-1. The second current cut-off device 22 further includes a third switch device SD3-2, which is arranged on the second main branch A-2, between the third terminal T3 and the first connection N1-2 between the first auxiliary branch B-2 and the second main branch A-2. In other words, in the portion between the first connection of the first auxiliary branch and the second connection of the first auxiliary branch, the first and second main branches each include a series connection of the first mechanical circuit breaker and the third switch device.
[0158] Each switching device SD1-1, SD1-2, SD2-1, SD2-2, SD3-1, SD3-2 can be a two-position disconnector or a three-position disconnector. A two-position disconnector has only two stable positions: a first position, called the closed position, in which the movable contact is in contact with the fixed contact, allowing the current to flow; a second position, called the open position, in which the movable contact is separated from the fixed contact, interrupting the current flow. This type of disconnector is also called an isolator switch. A three-position disconnector has three stable positions: the two positions already mentioned, plus a third position in which the movable contact is grounded. This type of disconnector is also called an earthing switch.
[0159] In the example shown, the second switching device SD2-1, SD2-2 and the third switching device SD3-1, SD3-2 are grounding switches. The second switching device SD2-1, SD2-2 and the third switching device SD3-1, SD3-2 provide the ability to safely discharge the capacitor of the commutation circuit. In the example shown, the switching devices SD1-1, SD1-2 are double-position disconnecting switches.
[0160] Figure 3 An embodiment of a current interruption device 20 is schematically illustrated, which is derived from Figure 2 The embodiment shown.
[0161] In this embodiment of the current interruption device 20:
[0162] The first mechanical circuit breaker CB1-1 of the first current interruption device 21, the second mechanical circuit breaker CB2-1 of the first current interruption device 21, the second switch device SD2-1 of the first current interruption device 21, and
[0163] The first mechanical circuit breaker CB1 - 2 of the second current interruption device 22 , the second mechanical circuit breaker CB2 - 2 of the second current interruption device 22 , and the second switch device SD2 - 2 of the second current interruption device 22 are arranged in the gas insulation box 11 .
[0164] Integrating the different mechanical circuit breakers CB1-1, CB1-2, CB2-1, CB2-2 in a common gas-insulated box 11 provides electrical insulation properties and environmental sensitivity, making the solution robust and reliable. In addition, when the different components are arranged in a common gas-insulated box 11, synchronization of the operation of the first mechanical circuit breakers CB1-1, CB1-2 and the second mechanical circuit breakers CB2-1, CB2-2 of the two current-breaking devices 21, 22 becomes easier. The installation of the current-breaking device 20 and its future maintenance are simplified.
[0165] exist Figure 3 In the example, the third switch devices SD3 - 1 , SD3 - 2 and the first switch devices SD1 - 1 , SD1 - 2 are also integrated in the gas insulation box 11 .
[0166] More precisely:
[0167] a first mechanical circuit breaker CB1-1 of the first current cutoff device 21, a second mechanical circuit breaker CB2-1 of the first current cutoff device 21, a first switch device SD1-1 of the first current cutoff device 21, a second switch device SD2-1 of the first current cutoff device 21, a third switch device SD3-1 of the first current cutoff device 21, and
[0168] The first mechanical circuit breaker CB1-2 of the second current cutting device 22, the second mechanical circuit breaker CB2-2 of the second current cutting device 22, the first switch device SD1-2 of the second current cutting device 22, the second switch device SD2-2 of the second current cutting device 22, and the third switch device SD3-2 of the second current cutting device 22 are arranged in the gas insulation box 11.
[0169] The integration of different mechanical circuit breakers and earthing switches further allows for a more compact design.
[0170] exist Figure 3 In the embodiment of FIG. 1 , the capacitor bank CA- 1 , the inductor L- 1 , the resistor R- 1 and the surge arrester SA- 1 of the first current cut-off device 21 are arranged in the first metal enclosed compartment 13 .
[0171] Furthermore, the capacitor bank CA- 2 , the inductor L- 2 , the resistor R- 2 , and the surge arrester SA- 2 of the second current cutoff device 22 are disposed in the second metal enclosed compartment 14 .
[0172] The assembly of each current interruption device 21 , 22 is easier when the respective capacitor bank, inductor, resistor and surge arrester form a pre-assembled module.
[0173] exist Figure 4 In the variant shown, the first metal closed compartment 13 and the second metal closed compartment 14 are the same metal closed compartment.
[0174] The capacitor bank CA-1, inductor L-1, resistor R-1, surge arrester SA-1 of the first current cut-off device 21, and the capacitor bank CA-2, inductor L-2, resistor R-2, and surge arrester SA-2 of the second current cut-off device 22 are arranged in a common metal enclosed compartment 13'.
[0175] The main components for generating the oscillating current for zero crossing and current interruption in the main branches A-1 and A-2 are all integrated in a common housing, making their integration easier.
Claims
1. A current cut-off device (20), comprising: - a first current cut-off device (21), for interrupting the flow of current in a first high-voltage direct current path between the first terminal (T1) and the second terminal (T2), comprising: a first main branch (A-1) inserted into the first DC path, comprising a first mechanical circuit breaker (CB1-1), the first mechanical circuit breaker (CB1-1) being normally closed, a first auxiliary branch (B-1), connected in parallel to the first mechanical circuit breaker (CB1-1), comprising a series connection of a capacitor bank (CA-1), an inductor (L-1) and a second mechanical circuit breaker (CB2-1) called a first reversing switch, the second mechanical circuit breaker (CB2-1) being normally open, -- Surge arrester (SA-1) connected in parallel with capacitor bank (CA-1), a second auxiliary branch (C-1) connecting a first intermediate terminal (I1-1) comprised between the capacitor bank (CA-1) and the inductor (L-1) to a ground connection, the second auxiliary branch (C-1) comprising a resistor (R-1), The second mechanical circuit breaker (CB2-1) is configured to close the first auxiliary branch (B-1) in response to the occurrence of a fault current in the first main branch (A-1), thereby generating a current that is superimposed on the current flow in the first main branch (A-1) and causes a current zero crossing in the first main branch (A-1).
2. The current interruption device (20) according to claim 1, further comprising: - a second current cut-off device (22), for interrupting the flow of current in a second high-voltage direct current path between the third terminal (T3) and the fourth terminal (T4), comprising: a second main branch (A-2) inserted into the second DC path, comprising a first mechanical circuit breaker (CB1-2), the first mechanical circuit breaker (CB1-2) being normally closed, a first auxiliary branch (B-2) connected in parallel to a first mechanical circuit breaker (CB1-2), comprising a series connection of a capacitor bank (CA-2), an inductor (L-2) and a second mechanical circuit breaker (CB2-2) called a reversing switch, the second mechanical circuit breaker (CB2-2) being normally open, -- Surge arrester (SA-2) connected in parallel with capacitor bank (CA-2), a second auxiliary branch (C-2) connecting the first intermediate terminal (I1-2) comprised between the capacitor bank (CA-2) and the inductor (L-2) to the ground connection, the second auxiliary branch (C-2) comprising a resistor (R-2), The second mechanical circuit breaker (CB2-2) is configured to close the first auxiliary branch (B-2) in response to the occurrence of a fault current in the second main branch (A-2), thereby generating a current that is superimposed on the current flow in the second main branch (A-2) and causes a current zero crossing in the second main branch (A-2).
3. The current interruption device (20) according to claim 2, wherein: - a first high voltage direct current path connected to a first pole of a hybrid AC / DC network (50), and - A second high voltage DC path is connected to a second pole of the hybrid AC / DC network (50).
4. The current interruption device (20) according to claim 2 or 3, wherein: The first current interruption device (21) and the second current interruption device (22) are identical.
5. The current interruption device (20) according to claim 2 or 3, wherein: - the capacitance of the capacitor bank (CA-1) of the first current interruption device (21) is different from the capacitance of the capacitor bank (CA-2) of the second current interruption device (22), and / or - the inductance of the inductor (L-1) of the first current interruption device (21) is different from the inductance of the inductor (L-2) of the second current interruption device (22), and / or - the resistance of the resistor (R-1) of the first current interruption device (21) is different from the resistance of the resistor (R-2) of the second current interruption device (22).
6. The current interruption device (20) according to any one of the preceding claims, wherein: The first current cut-off device (21) further comprises a first switching device (SD1-1), which is arranged on the first auxiliary branch (B-1) and is located between the inductor (L-1) and a second connection (N2-1) between the first auxiliary branch (B-1) and the first main branch (A-1).
7. A current interruption device (20) according to any one of the preceding claims in combination with claim 2, wherein: The second current cut-off device (22) further comprises a first switching device (SD1-2), which is arranged on the first auxiliary branch (B-2) and is located between the inductor (L-2) and the second connection (N2-2) between the first auxiliary branch (B-2) and the second main branch (A-2).
8. A current interruption device (20) according to any one of the preceding claims in combination with claims 6 and 7, wherein: - the second mechanical circuit breaker (CB2-1) of the first current-breaking device (21) is different from the second mechanical circuit breaker (CB2-2) of the second current-breaking device (22), and / or - the first switching device (SD1-1) of the first current interruption device (21) is different from the first switching device (SD1-2) of the second current interruption device (22).
9. The current interruption device (20) according to any one of the preceding claims, wherein: The first current cut-off device (21) further comprises a second switch device (SD2-1), which is arranged on the first main branch (A-1) and is located between a first connection (N1-1) between the first auxiliary branch (B-1) and the first main branch (A-1) and a second connection (N2-1) between the first auxiliary branch (B-1) and the first main branch (A-1).
10. A current interruption device (20) according to any one of the preceding claims in combination with claim 2, wherein: The second current cut-off device (22) further includes a second switch device (SD2-2), which is arranged on the second main branch (A-2) and is located between the first connection (N1-2) between the first auxiliary branch (B-2) and the second main branch (A-2) and the second connection (N2-2) between the first auxiliary branch (B-2) and the second main branch (A-2).
11. The current interruption device (20) according to any one of the preceding claims, wherein: The first current cut-off device (21) further comprises a third switch device (SD3-1), which is arranged on the first main branch (A-1) and is located between the first terminal (T1) and the first connection (N1-1) between the first auxiliary branch (B-1) and the first main branch (A-1).
12. A current interruption device (20) according to any one of the preceding claims in combination with claim 2, wherein: The second current cut-off device (22) further comprises a third switch device (SD3-2), which is arranged on the second main branch (A-2) and is located between the third terminal (T3) and the first connection (N1-2) between the first auxiliary branch (B-2) and the second main branch (A-2).
13. A current interruption device (20) according to any one of the preceding claims in combination with claims 9 and 10, wherein: - a first mechanical circuit breaker (CB1-1) of the first current breaking device (21), a second mechanical circuit breaker (CB2-1) of the first current breaking device (21), a second switch device (SD2-1) of the first current breaking device (21), and - A first mechanical circuit breaker (CB1-2) of the second current breaking device (22), a second mechanical circuit breaker (CB2-2) of the second current breaking device (22), and a second switch device (SD2-2) of the second current breaking device (22) are arranged in a gas insulation box (11).
14. The current interruption device (20) according to claim 13 in combination with claims 6, 7, 11, 12, wherein: - a first mechanical circuit breaker (CB1-1) of the first current disconnecting device (21), a second mechanical circuit breaker (CB2-1) of the first current disconnecting device (21), a first switch device (SD1-1) of the first current disconnecting device (21), a second switch device (SD2-1) of the first current disconnecting device (21), a third switch device (SD3-1) of the first current disconnecting device (21), and -The first mechanical circuit breaker (CB1-2) of the second current cutting device (22), the second mechanical circuit breaker (CB2-2) of the second current cutting device (22), the first switch device (SD1-2) of the second current cutting device (22), the second switch device (SD2-2) of the second current cutting device (22), and the third switch device (SD3-2) of the second current cutting device (22) are arranged in the gas insulation box (11).
15. The current interruption device (20) according to any one of the preceding claims, wherein The capacitor bank (CA-1), the inductor (L-1), the resistor (R-1) and the surge arrester (SA-1) of the first current interruption device (21) are arranged in a first metal-enclosed compartment (13).
16. A current interruption device (20) according to any of the preceding claims in combination with claim 2, wherein the capacitor bank (CA-2), the inductor (L-2), the resistor (R-2) and the surge arrester (SA-2) of the second current interruption device (22) are arranged in the second metal enclosed compartment (14).
17. The current interruption device (20) according to any one of claims 1 to 14 in combination with claim 2, wherein: The capacitor bank (CA-1), inductor (L-1), resistor (R-1), surge arrester (SA-1) of the first current cut-off device (21) and the capacitor bank (CA-2), inductor (L-2), resistor (R-2) and surge arrester (SA-2) of the second current cut-off device (22) are arranged in a common metal enclosed compartment (13').