IGBT-based low-voltage switch short-circuit protection and fault detection circuit and method

Abstract

The invention discloses a low-voltage switch short-circuit protection and fault detection circuit and method based on an IGBT (Insulated Gate Bipolar Translator). The method comprises the following steps: judging whether a fault exists at a wire outlet end or not according to acquired voltage and current information at the wire outlet end; when the wire outlet end has no fault, the current of the power supply is transmitted to the wire outlet end, and when the wire outlet end has a fault, the current is stopped being transmitted to the wire outlet end; and when the fault type of the wire outlet end is a transient fault, the IGBT is controlled to be switched on to enable the power supply current to bypass the low-voltage switch main loop to be transmitted to the wire outlet end, and the IGBT is controlled to be switched off after the transient fault is removed, so that the current is transmitted to the wire outlet end again through the low-voltage switch main loop. According to the invention, pre-overlapping is carried out through the fault pre-overlapping loop after the fault occurs, the voltage transformer and the current transformer are used for detecting the outgoing voltage and the outgoing current in real time, and the intelligent control terminal outputs a signal to control the low-voltage circuit breaker to be closed after judging that the outgoing fault is removed, so that the low-voltage circuit breaker is prevented from being subjected to secondary impact; and the intelligent control terminal controls the closing time to reduce the switching loss.

Description

Technical Field

[0001] The present invention relates to the technical field of electric power equipment, and in particular to an IGBT-based low-voltage switch short-circuit protection and fault detection circuit and method. Background Art

[0002] At present, the protection method of 380 / 220V low-voltage distribution cabinet has certain limitations. Some low-voltage distribution cabinets are equipped with only fuses as overload and instantaneous fault protection. Although the fuse can be automatically blown when certain faults occur, the staff needs to go to the distribution room to replace it after the fault occurs, which seriously affects the continuity and reliability of power supply. In addition, the existing method cannot accurately detect and classify faults, and it is difficult to realize intelligent management. When facing complex faults, the processing efficiency is low, and the stability of the power supply system is insufficient. To solve these problems, the present invention aims to design a low-voltage Internet of Things switch with short-circuit protection and fault detection functions, and use IGBT technology, voltage transformer and current transformer to collect the voltage and current information of the power switch outlet in real time, so as to realize accurate judgment and processing of faults. This can not only improve the efficiency of fault handling, enhance the stability and automation of the power supply system, but also avoid the low-voltage circuit breaker from being subjected to secondary impact, reduce the switch loss, and realize soft switching through the intelligent control terminal, so as to better meet the operation requirements of the modern power system. Summary of the invention

[0003] The purpose of the present invention is to provide a low-voltage switch short-circuit protection and fault detection circuit based on IGBT on the one hand, and a low-voltage switch short-circuit protection and fault detection method based on IGBT on the other hand. The circuit and method can perform pre-reclosing through a fault pre-reclosing circuit after a fault occurs at the output end of a power switch, and use a voltage transformer and a current transformer to detect the output voltage and output current in real time. After the intelligent control terminal determines that the output fault is resolved, it outputs a signal to control the low-voltage circuit breaker to close, thereby avoiding secondary impact on the low-voltage circuit breaker. At the same time, the intelligent control terminal controls the closing time to reduce switch losses and realize soft switching.

[0004] To achieve this purpose, the present invention is a low-voltage switch short-circuit protection and fault detection circuit based on IGBT, characterized in that it includes: a low-voltage switch main circuit, a fault detection module, and an outlet terminal fault pre-reclosing module;

[0005] The fault detection module is used to collect voltage and current information of the power switch output terminal through a voltage transformer and a current transformer, and judge whether there is a fault at the power switch output terminal according to the collected voltage and current information at the power switch output terminal, and judge the fault type when there is a fault at the power switch output terminal;

[0006] The main circuit of the low-voltage switch is used to transmit the current of the power supply to the output terminal of the power switch when there is no fault at the output terminal of the power switch. When there is a fault at the output terminal of the power switch, the main circuit of the low-voltage switch is disconnected and stops transmitting the power current to the output terminal of the power switch;

[0007] The output terminal fault pre-reclosing module is used to control the IGBT to turn on when the fault type at the output terminal of the power switch is a transient fault, so that the power current bypasses the circuit breaker and fuse of the low-voltage switch main circuit and is transmitted to the output terminal of the power switch. After the transient fault is relieved, the IGBT is controlled to be disconnected, so that the power current is transmitted to the output terminal of the power switch through the low-voltage switch main circuit again.

[0008] Furthermore, the collected voltage and current information of the power switch output terminal is transmitted to the intelligent control terminal through the signal bus of the secondary system loop, and the intelligent control terminal controls the conduction and disconnection of the IGBT and the low-voltage circuit breaker according to the voltage and current information of the power switch output terminal.

[0009] Furthermore, the low-voltage circuit breaker is used to automatically disconnect when a fault occurs at the outlet of the power switch and the short-circuit current is lower than the selective limit current, so that the current cannot be transmitted to the outlet through the low-voltage fuse and the low-voltage circuit breaker of the main circuit of the low-voltage switch;

[0010] The low-voltage fuse is used to automatically disconnect when a fault occurs at the output end of the power switch and the short-circuit current is higher than the selective limit current, so that the current cannot be transmitted to the output line through the low-voltage fuse and low-voltage circuit breaker of the low-voltage switch main circuit.

[0011] Furthermore, the IGBT is controlled by an intelligent control terminal. When a fault occurs at the output end of the power switch, the intelligent control terminal controls the IGBT to turn on, and the power current is transmitted to the output end of the power switch through the fault pre-reclosing circuit where the IGBT is located. When the instantaneous fault at the output end of the power switch is removed, the intelligent control terminal controls the IGBT to disconnect, so that the power current cannot be transmitted to the output end of the power switch through the fault pre-reclosing circuit where the IGBT is located, and the power current is re-transmitted to the output end of the power switch through the low-voltage switch main circuit.

[0012] Furthermore, the voltage transformer is used to collect voltage information of the fault pre-reclosing circuit and the main circuit of the low-voltage switch, and the current transformer is used to collect current information of the fault pre-reclosing circuit and the main circuit of the low-voltage switch.

[0013] Furthermore, the low-voltage switch main circuit includes a low-voltage fuse FU A1 And low voltage circuit breaker QF A1 , among which, low voltage fuse FU A1 One end of the current transformer CT A1 The first power terminal, low voltage fuse FU A1The other end is connected to the low voltage circuit breaker QF A1 One end of the low voltage circuit breaker QF A1 The other end is connected to the voltage transformer PT A1 One end of the low voltage circuit breaker QF A1 The other end is the power switch outlet.

[0014] Furthermore, the secondary system loop includes a voltage transformer PT A1 and current transformer CT A1 , where the current transformer CT A1 The second power supply terminal is connected to the power supply current A phase incoming line terminal, the current transformer CT A1 The current signal bus terminal is connected to the current signal acquisition terminal of the intelligent control terminal through the A-phase CT signal bus, and the voltage transformer PT A1 One end is connected to the output terminal of the A-phase power switch, and the voltage transformer PT A1 One end of the voltage transformer PT is also grounded. A1 The other end is connected to the voltage signal acquisition end of the intelligent control terminal through the A-phase PT signal bus.

[0015] Furthermore, the fault pre-closing circuit includes a current transformer CT A 、IGBT A1 , low voltage fuse FU A0 and current limiting reactor LA A , among which, low voltage fuse FU A0 One end of the current transformer CT A The first power supply terminal, current transformer CT A The second power supply terminal is connected to the power supply current A phase incoming line terminal, the current transformer CT A The current signal bus terminal is connected to the current signal acquisition terminal of the intelligent control terminal through the A-phase CT signal bus, and the low-voltage fuse FU A0 The other end is connected to the current limiting reactor LA A At one end, the current limiting reactor LA A The other end is connected to the IGBT A1 The emitter of IGBT A1 The collector of the voltage transformer PT is connected A1 The other end of the IGBT A1 The gate is connected to the driving circuit.

[0016] Furthermore, the method for the intelligent control terminal to control the on and off of the IGBT and the low-voltage circuit breaker according to the voltage and current information of the power switch outlet terminal includes: the current transformer and the voltage transformer transmit the collected voltage and current information of the power switch outlet terminal to the intelligent control terminal, and the intelligent control terminal compares the collected voltage value and current value of the power switch outlet terminal with the normal current value and voltage value. When the collected voltage value and current value of the power switch outlet terminal suddenly change and exceed the normal working range, it indicates that the power switch outlet terminal fails, and the intelligent control terminal sends a signal through the CT signal bus and the PT signal bus. Send control instructions to control the IGBT to turn on, the low-voltage circuit breaker to disconnect, the low-voltage switch main circuit to be powered off, and the fault pre-reclosing circuit to start working. The voltage and current information of the low-voltage switch main circuit and the fault pre-reclosing circuit are continuously collected through the current transformer and the voltage transformer. The type of fault and whether the fault is relieved are determined based on the voltage and current information of the low-voltage switch main circuit and the fault pre-reclosing circuit. If the fault is a transient fault, after the transient fault is relieved, the intelligent control terminal sends a control instruction again to control the IGBT to disconnect, the low-voltage circuit breaker to turn on, the low-voltage switch main circuit to resume normal operation, and the fault pre-reclosing circuit to be powered off.

[0017] Furthermore, the low-voltage switch short-circuit protection and fault detection method of the IGBT-based low-voltage switch short-circuit protection and fault detection circuit is characterized in that it includes:

[0018] The voltage and current information of the output terminal of the power switch is collected through the voltage transformer and the current transformer, and according to the collected voltage and current information of the output terminal of the power switch, whether the output terminal of the power switch has a fault is judged, and if there is a fault at the output terminal of the power switch, the fault type is judged;

[0019] When there is no fault at the power switch outlet, the power supply current is transmitted to the power switch outlet. When there is a fault at the power switch outlet, the main circuit of the low-voltage switch is disconnected, and the power supply current is stopped from being transmitted to the power switch outlet.

[0020] When the fault type at the output end of the power switch is a transient fault, the IGBT is controlled to be turned on so that the power current bypasses the circuit breaker and fuse of the low-voltage switch main circuit and is transmitted to the output end of the power switch. After the transient fault is eliminated, the IGBT is controlled to be disconnected so that the power current is transmitted to the output end of the power switch again through the low-voltage switch main circuit.

[0021] Beneficial effects of the present invention: In terms of fault handling, the present invention no longer relies on manual replacement of fuses, but performs pre-reclosing through a fault pre-reclosing circuit, and uses voltage transformers and current transformers to collect voltage and current information at the outlet of the power switch in real time. The intelligent control terminal can quickly and accurately determine the fault type, greatly improving the efficiency of fault handling. When encountering a transient fault, the IGBT can be controlled to conduct to allow the power current to bypass the circuit breaker and fuse of the main circuit of the low-voltage switch and be transmitted to the outlet of the power switch. After the fault is removed, the IGBT can be controlled to disconnect and restore normal power supply in time, effectively reducing the power outage time and enhancing the stability of the power supply system. At the same time, when the fault is not completely removed, the intelligent control terminal will not blindly control the low-voltage circuit breaker to close, avoiding the low-voltage circuit breaker from being subjected to secondary impact and extending its service life. Moreover, the intelligent control terminal can accurately control the closing time, realize soft switching, reduce switch losses, and reduce equipment maintenance costs. In addition, the present invention realizes accurate detection and classification of faults, cooperates with the intelligent control terminal, achieves intelligent management, can better deal with complex faults, meet the high requirements of modern power systems for stability and automation, and improve the reliability and operation efficiency of the overall power supply system. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A circuit diagram of normal disconnection, short circuit protection and fault detection of a low-voltage switch of an IGBT of the present invention;

[0023] Figure 2 It is the low-voltage switch main circuit of the A-phase outlet 1 of the present invention;

[0024] Figure 3 It is a fault pre-reclosing circuit of the A-phase outgoing line 1 of the present invention;

[0025] Figure 4 The secondary system loop of the present invention;

[0026] Figure 5 It is a structural schematic diagram of the present invention. DETAILED DESCRIPTION

[0027] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments:

[0028] like Figure 5 As shown, a low-voltage switch short-circuit protection and fault detection circuit based on IGBT includes: a low-voltage switch main circuit, a fault detection module, and an outlet fault pre-reclosing module;

[0029] The fault detection module is used to collect voltage and current information of the power switch output terminal through a voltage transformer and a current transformer, and judge whether there is a fault at the power switch output terminal according to the collected voltage and current information at the power switch output terminal, and judge the fault type when there is a fault at the power switch output terminal;

[0030] The main circuit of the low-voltage switch is used to transmit the current of the power supply to the output terminal of the power switch when there is no fault at the output terminal of the power switch. When there is a fault at the output terminal of the power switch, the main circuit of the low-voltage switch is disconnected and stops transmitting the power current to the output terminal of the power switch;

[0031] The output terminal fault pre-reclosing module is used to control the IGBT to turn on when the fault type at the output terminal of the power switch is a transient fault, so that the power current bypasses the circuit breaker and fuse of the low-voltage switch main circuit and is transmitted to the output terminal of the power switch. After the transient fault is relieved, the IGBT is controlled to be disconnected, so that the power current is transmitted to the output terminal of the power switch through the low-voltage switch main circuit again.

[0032] In the above technical solution, the collected voltage and current information of the power switch output terminal is transmitted to the intelligent control terminal through the signal bus of the secondary system loop. The intelligent control terminal controls the conduction and disconnection of the IGBT and the low-voltage circuit breaker according to the voltage and current information of the power switch output terminal.

[0033] The intelligent control terminal is the core control unit and intelligent decision-making center of the power system. During the stable operation period when the power switch output terminal is fault-free, the intelligent control terminal continuously receives the voltage and current data of the low-voltage switch main circuit transmitted from the secondary system circuit, analyzes and processes the voltage and current data of the low-voltage switch main circuit in real time, and determines whether the operation status of the power system is normal. When the operation status is normal, it adjusts the voltage U between the gate and emitter of the IGBT. GE , ensuring that the IGBT is in the disconnected state, thereby isolating the fault pre-reclosing circuit from the main circuit, avoiding interference with the normal operation of the main circuit and maintaining stable power supply of the power system.

[0034] When a fault occurs in the outgoing line, the intelligent control terminal immediately enters the fault handling mode, receives the voltage and current signals of the low-voltage switch main circuit and the fault pre-reclosing circuit collected by the secondary circuit, and determines whether the fault at the outgoing end of the power switch is a transient fault or a permanent fault. The judgment method is as follows: after the fault occurs, the intelligent control terminal controls the IGBT to close, the fault pre-reclosing circuit is put into operation, and the collected current, voltage and other parameters of the fault detection circuit and the low-voltage switch main circuit are analyzed. If the fault signal disappears within a short period of time (such as tens of milliseconds to a few seconds), and the various electrical parameters return to the normal range, it is judged as a transient fault; if the fault signal persists and the electrical parameters cannot return to normal, it is judged as a permanent fault. Based on the judgment result, the intelligent control terminal quickly generates the corresponding control strategy and outputs the control signal to adjust the voltage U between the gate and emitter of the IGBT GE, control the IGBT to close, so that the fault pre-reclosing circuit is put into operation, so as to further detect the fault. The process of putting the fault pre-reclosing circuit into operation is also called the pre-reclosing process. After the pre-reclosing is successful, when the fault type at the outlet of the power switch is a transient fault, the intelligent control terminal confirms that the transient fault has been completely eliminated based on the voltage and current signals of the fault pre-reclosing circuit collected by the secondary system circuit. After the power system has the conditions for safe and stable operation, the intelligent control terminal will output a control signal to control the low-voltage circuit breaker to close and restore the normal power supply of the circuit, ensuring that the power system can return to normal operation as soon as possible and guarantee the user's electricity demand. When the fault type at the outlet of the power switch is a permanent fault, the power should be cut off immediately and manual maintenance should be carried out.

[0035] The pre-reclosing operation avoids the low-voltage circuit breaker from blindly closing and being subjected to secondary shock when the fault is not confirmed to be eliminated. If the circuit breaker is closed directly without pre-reclosing, a large current may be generated at the moment of closing to shock the low-voltage circuit breaker due to the failure to eliminate the fault, accelerating the wear of its contacts and increasing the switching loss. During pre-reclosing, the IGBT is first turned on for fault detection and judgment, and the low-voltage circuit breaker is closed only after the fault is confirmed to be eliminated, which reduces this risk and effectively reduces the switching loss.

[0036] In the above technical solution, the low-voltage circuit breaker is used to automatically disconnect when a fault occurs at the outlet of the power switch and the short-circuit current is lower than the selective limit current, so that the current cannot be transmitted to the outlet through the low-voltage fuse and the low-voltage circuit breaker of the main circuit of the low-voltage switch;

[0037] The low-voltage fuse is used to automatically disconnect when a fault occurs at the outlet of the power switch and the short-circuit current is higher than the selective limiting current, so that the current cannot be transmitted to the outlet through the low-voltage fuse and low-voltage circuit breaker of the main circuit of the low-voltage switch. The selective limiting current refers to the maximum current value at which the load-side protection device can complete the disconnection action in time to prevent the upper-level protection device from starting to act when two overcurrent protection devices such as fuses or circuit breakers connected in series exist in the circuit.

[0038] When there is no fault in the outlet of the power switch in the main circuit of the low-voltage switch, the low-voltage circuit breaker is closed, and the power current is transmitted to the outlet of the power switch through the low-voltage fuse and the low-voltage circuit breaker. The low-voltage circuit breaker and the low-voltage fuse are set at the same time in the main circuit of the low-voltage switch to achieve hierarchical protection. When the short-circuit current of the main circuit of the low-voltage switch is small, the low-voltage circuit breaker automatically cuts off the circuit, can quickly respond to faults, and protect the line and equipment; when the short-circuit current is large, the low-voltage fuse quickly blows, which can effectively cut off the strong current and prevent the excessive current from causing serious damage to the equipment. If a low-voltage circuit breaker is not set, when the short-circuit current is small, it is only protected by the low-voltage fuse. Due to its action characteristics, it may not be able to cut off the current in time, causing the line and equipment to bear overload current for a long time, accelerating equipment aging, and even causing fire. If a low-voltage fuse is not set, when the short-circuit current is high, the low-voltage circuit breaker may be damaged due to its inability to withstand the huge current, and the circuit cannot be effectively cut off, which makes the equipment face a greater risk of damage and affects the stability and reliability of the power supply system.

[0039] In the above technical solution, the IGBT is controlled by an intelligent control terminal. When a fault occurs at the output end of the power switch, the intelligent control terminal controls the IGBT to be turned on, and the power current is transmitted to the output end of the power switch through the fault pre-reclosing circuit where the IGBT is located. When the instantaneous fault at the output end of the power switch is removed, the intelligent control terminal controls the IGBT to be disconnected, so that the power current cannot be transmitted to the output end of the power switch through the fault pre-reclosing circuit where the IGBT is located, and the power current is re-transmitted to the output end of the power switch through the low-voltage switch main circuit.

[0040] The fault pre-reclosing circuit plays the role of fault detection and pre-reclosing. During the normal operation of the power switch outlet, the IGBT in the fault pre-reclosing circuit is in the cut-off state, so that the current cannot flow to the power switch outlet through the low-voltage fuse, current-limiting reactor and IGBT, ensuring that the circuit will not cause any interference to the operation of the low-voltage switch main circuit under normal circumstances. Once a fault occurs at the power switch outlet, the low-voltage switch main circuit is disconnected, and the outlet is powered off, the fault pre-reclosing circuit can respond quickly. The IGBT is quickly turned on under the control signal of the intelligent control terminal to pre-reclose, and the secondary system circuit transmits the voltage and current signals of the fault pre-reclosing circuit to the intelligent control terminal for judgment. At this time, if the outlet is judged to be a transient fault, the main circuit can be closed to restore the power supply of the outlet; if the outlet is judged to be a permanent fault, the main circuit will not be closed to avoid the direct closure of the main circuit to cause excessive current and irreversible damage to the equipment.

[0041] The conduction of IGBT provides the necessary electrical path for fault detection, enabling subsequent detection equipment to accurately obtain fault signals. By analyzing parameters such as current and voltage, accurate judgment of the fault type, location and severity can be achieved, providing strong support for rapid fault handling and system recovery.

[0042] In the above technical solution, the voltage transformer is used to collect voltage information of the fault preclosing circuit and the low-voltage switch main circuit, and the current transformer is used to collect current information of the fault preclosing circuit and the low-voltage switch main circuit.

[0043] The secondary circuit is responsible for signal acquisition and transmission. Its main responsibility is to collect the voltage and current in the circuit in real time and accurately, and transmit these data reliably to the intelligent control terminal. In the normal operation stage with no fault in the outgoing line, the secondary circuit accurately measures and converts the voltage and current of the main circuit of the low-voltage switch through the voltage transformer and the current transformer. Then, through a special signal transmission bus, these data are stably transmitted to the intelligent control terminal, providing basic data for the intelligent control terminal to monitor and analyze the system operation status in real time.

[0044] When a fault occurs in the outgoing line, the acquisition scope of the secondary system circuit is further expanded. Not only does it continuously monitor the voltage and current changes of the low-voltage switch main circuit, but it also includes the voltage and current signals of the fault pre-reclosing circuit in the acquisition scope. Through the comprehensive acquisition of these multi-dimensional signals, it is possible to fully obtain the changes in electrical parameters after the fault occurs, providing more abundant data support for the intelligent control terminal to accurately judge the nature of the fault and formulate reasonable control strategies. After the pre-reclosing is successful in the fault handling process, the secondary circuit focuses on the voltage and current signals of the fault pre-reclosing circuit. Through continuous monitoring of these signals, it is determined whether the fault has been completely eliminated, providing a key basis for the intelligent control terminal to decide whether to restore normal power supply.

[0045] like Figure 1 As shown, each phase of the three-phase power supply can be connected to multiple power current output lines, each power current output line is connected to an electrical device, and the power switch output end is a distribution line between the power switch outlet and the electrical device.

[0046] like Figure 2 As shown, in the above technical solution, the low-voltage switch main circuit of the A-phase power switch output terminal 1 includes a low-voltage fuse FU A1 And low voltage circuit breaker QF A1 , among which, low voltage fuse FU A1 One end of the current transformer CT A1 The first power terminal, low voltage fuse FU A1 The other end is connected to the low voltage circuit breaker QF A1 One end of the low voltage circuit breaker QF A1 The other end is connected to the voltage transformer PT A1 One end of the low voltage circuit breaker QF A1 The other end is the A-phase power switch output terminal 1.

[0047] like Figure 1 As shown, the low-voltage switch main circuit of the A-phase power switch output terminal 2 includes a low-voltage fuse FU A2 And low voltage circuit breaker QF A2 , among which, low voltage fuse FU A2 One end of the current transformer CT A2 The first power terminal, low voltage fuse FU A2 The other end is connected to the low voltage circuit breaker QF A2 One end of the low voltage circuit breaker QF A2 The other end is connected to the voltage transformer PT A2 One end of the low voltage circuit breaker QF A2 The other end is the A-phase power switch output terminal 2; the low-voltage switch main circuit of the A-phase power switch output terminal 3 includes a low-voltage fuse FU A3 And low voltage circuit breaker QF A3 , among which, low voltage fuse FU A3 One end of the current transformer CT A3 The first power terminal, low voltage fuse FU A3 The other end is connected to the low voltage circuit breaker QF A3 One end of the low voltage circuit breaker QF A3 The other end is connected to the voltage transformer PT A3 One end of the low voltage circuit breaker QF A3 The other end is the A-phase power switch output terminal 3; the low-voltage switch main circuit of the A-phase power switch output terminal 4 includes a low-voltage fuse FU A4 And low voltage circuit breaker QF A4 , among which, low voltage fuse FU A4 One end of the current transformer CT A4 The first power terminal, low voltage fuse FU A4 The other end is connected to the low voltage circuit breaker QF A4 One end of the low voltage circuit breaker QF A4 The other end is connected to the voltage transformer PT A4 One end of the low voltage circuit breaker QF A4 The other end is the A-phase power switch output terminal 4, and so on, the low-voltage switch main circuit of the A-phase power switch output terminal n includes a low-voltage fuse FU An And low voltage circuit breaker QF An , among which, low voltage fuse FU An One end of the current transformer CT An The first power terminal, low voltage fuse FU An The other end is connected to the low voltage circuit breaker QF An One end of the low voltage circuit breaker QF An The other end is connected to the voltage transformer PT AnOne end of the low voltage circuit breaker QF An The other end is the A-phase power switch output terminal n, where n depends on the number of power switch output terminals (power-consuming equipment).

[0048] The low-voltage switch main circuit of the B-phase power switch output terminal 1 includes a low-voltage fuse FU B1 And low voltage circuit breaker QF B1 , among which, low voltage fuse FU B1 One end of the current transformer CT B1 The first power terminal, low voltage fuse FU B1 The other end is connected to the low voltage circuit breaker QF B1 One end of the low voltage circuit breaker QF B1 The other end is connected to the voltage transformer PT B1 One end of the low voltage circuit breaker QF B1 The other end is the B-phase power switch output terminal 1; the low-voltage switch main circuit of the B-phase power switch output terminal 2 includes a low-voltage fuse FU B2 And low voltage circuit breaker QF B2 , among which, low voltage fuse FU B2 One end of the current transformer CT B2 The first power terminal, low voltage fuse FU B2 The other end is connected to the low voltage circuit breaker QF B2 One end of the low voltage circuit breaker QF B2 The other end is connected to the voltage transformer PT B2 One end of the low voltage circuit breaker QF B2 The other end is the B-phase power switch output terminal 2; the low-voltage switch main circuit of the B-phase power switch output terminal 3 includes a low-voltage fuse FU B3 And low voltage circuit breaker QF B3 , among which, low voltage fuse FU B3 One end of the current transformer CT B3 The first power terminal, low voltage fuse FU B3 The other end is connected to the low voltage circuit breaker QF B3 One end of the low voltage circuit breaker QF B3 The other end is connected to the voltage transformer PT B3 One end of the low voltage circuit breaker QF B3 The other end is the B-phase power switch output terminal 3; the low-voltage switch main circuit of the B-phase power switch output terminal 4 includes a low-voltage fuse FU B4 And low voltage circuit breaker QF B4 , among which, low voltage fuse FU B4 One end of the current transformer CT B4 The first power terminal, low voltage fuse FU B4 The other end is connected to the low voltage circuit breaker QFB4 One end of the low voltage circuit breaker QF B4 The other end is connected to the voltage transformer PT B4 One end of the low voltage circuit breaker QF B4 The other end is the B-phase power switch output terminal 4, and so on, the low-voltage switch main circuit of the B-phase power switch output terminal n includes a low-voltage fuse FU Bn And low voltage circuit breaker QF Bn , among which, low voltage fuse FU Bn One end of the current transformer CT Bn The first power terminal, low voltage fuse FU Bn The other end is connected to the low voltage circuit breaker QF Bn One end of the low voltage circuit breaker QF Bn The other end is connected to the voltage transformer PT Bn One end of the low voltage circuit breaker QF Bn The other end is the B-phase power switch output terminal n, where n depends on the number of power switch output terminals (power-consuming equipment).

[0049] The low-voltage switch main circuit of the C-phase power switch output terminal 1 includes a low-voltage fuse FU C1 And low voltage circuit breaker QF C1 , among which, low voltage fuse FU C1 One end of the current transformer CT C1 The first power terminal, low voltage fuse FU C1 The other end is connected to the low voltage circuit breaker QF C1 One end of the low voltage circuit breaker QF C1 The other end is connected to the voltage transformer PT C1 One end of the low voltage circuit breaker QF C1 The other end is the C-phase power switch output terminal 1; the low-voltage switch main circuit of the C-phase power switch output terminal 2 includes a low-voltage fuse FU C2 And low voltage circuit breaker QF C2 , among which, low voltage fuse FU C2 One end of the current transformer CT C2 The first power terminal, low voltage fuse FU C2 The other end is connected to the low voltage circuit breaker QF C2 One end of the low voltage circuit breaker QF C2 The other end is connected to the voltage transformer PT C2 One end of the low voltage circuit breaker QF C2 The other end is the C-phase power switch output terminal 2; the low-voltage switch main circuit of the C-phase power switch output terminal 3 includes a low-voltage fuse FU C3 And low voltage circuit breaker QF C3 , among which, low voltage fuse FU C3One end of the current transformer CT C3 The first power terminal, low voltage fuse FU C3 The other end is connected to the low voltage circuit breaker QF C3 One end of the low voltage circuit breaker QF C3 The other end is connected to the voltage transformer PT C3 One end of the low voltage circuit breaker QF C3 The other end is the C-phase power switch output terminal 3; the low-voltage switch main circuit of the C-phase power switch output terminal 4 includes a low-voltage fuse FU C4 And low voltage circuit breaker QF C4 , among which, low voltage fuse FU C4 One end of the current transformer CT C4 The first power terminal, low voltage fuse FU C4 The other end is connected to the low voltage circuit breaker QF C4 One end of the low voltage circuit breaker QF C4 The other end is connected to the voltage transformer PT C4 One end of the low voltage circuit breaker QF C4 The other end is the C-phase power switch output terminal 4, and so on, the low-voltage switch main circuit of the C-phase power switch output terminal n includes a low-voltage fuse FU Cn And low voltage circuit breaker QF Cn , among which, low voltage fuse FU Cn One end of the current transformer CT Cn The first power terminal, low voltage fuse FU Cn The other end is connected to the low voltage circuit breaker QF Cn One end of the low voltage circuit breaker QF Cn The other end is connected to the voltage transformer PT Cn One end of the low voltage circuit breaker QF Cn The other end is the C-phase power switch output terminal n, where n depends on the number of power switch output terminals (power-consuming equipment).

[0050] like Figure 4 As shown, in the above technical solution, the secondary system circuit of the output terminal 1 of the A-phase power switch includes a voltage transformer PT A1 and current transformer CT A1 , where the current transformer CT A1 The second power supply terminal is connected to the power supply current A phase incoming line terminal, the current transformer CT A1 The current signal bus terminal is connected to the current signal acquisition terminal of the intelligent control terminal through the A-phase CT signal bus, and the voltage transformer PT A1 One end is connected to the output terminal of the A-phase power switch, and the voltage transformer PT A1 One end of the voltage transformer PT is also grounded. A1The other end is connected to the voltage signal acquisition end of the intelligent control terminal through the A-phase PT signal bus.

[0051] like Figure 1 As shown, the output terminal 2 of the A-phase power switch includes a voltage transformer PT A2 and current transformer CT A2 , where the current transformer CT A2 The second power supply terminal is connected to the power supply current A phase incoming line terminal, the current transformer CT A2 The current signal bus terminal is connected to the current signal acquisition terminal of the intelligent control terminal through the A-phase CT signal bus, and the voltage transformer PT A2 One end is connected to the output terminal of the A-phase power switch, and the voltage transformer PT A2 One end of the voltage transformer PT is also grounded. A2 The other end is connected to the voltage signal acquisition end of the intelligent control terminal through the A-phase PT signal bus; the A-phase power switch output terminal 3 includes a voltage transformer PT A3 and current transformer CT A3 , where the current transformer CT A3 The second power supply terminal is connected to the power supply current A phase incoming line terminal, the current transformer CT A3 The current signal bus terminal is connected to the current signal acquisition terminal of the intelligent control terminal through the A-phase CT signal bus, and the voltage transformer PT A3 One end is connected to the output terminal of the A-phase power switch, and the voltage transformer PT A3 One end of the voltage transformer PT is also grounded. A3 The other end is connected to the voltage signal acquisition end of the intelligent control terminal through the A-phase PT signal bus; the A-phase power switch output terminal 4 includes a voltage transformer PT A4 and current transformer CT A4 , where the current transformer CT A4 The second power supply terminal is connected to the power supply current A phase incoming line terminal, the current transformer CT A4 The current signal bus terminal is connected to the current signal acquisition terminal of the intelligent control terminal through the A-phase CT signal bus, and the voltage transformer PT A4 One end is connected to the output terminal of the A-phase power switch, and the voltage transformer PT A4 One end of the voltage transformer PT is also grounded. A4 The other end is connected to the voltage signal acquisition end of the intelligent control terminal through the A-phase PT signal bus; by analogy, the output terminal n of the A-phase power switch includes the voltage transformer PT An and current transformer CT An , where the current transformer CT An The second power supply terminal is connected to the power supply current A phase incoming line terminal, the current transformer CT AnThe current signal bus terminal is connected to the current signal acquisition terminal of the intelligent control terminal through the A-phase CT signal bus, and the voltage transformer PT An One end is connected to the output terminal of the A-phase power switch, and the voltage transformer PT An One end of the voltage transformer PT is also grounded. An The other end is connected to the voltage signal acquisition end of the intelligent control terminal through the A-phase PT signal bus, and n depends on the number of power switch output terminals (electrical equipment).

[0052] The secondary system circuit of the output terminal 1 of the B phase power switch includes a voltage transformer PT B1 and current transformer CT B1 , where the current transformer CT B1 The second power supply terminal is connected to the power supply current B phase incoming line terminal, the current transformer CT B1 The current signal bus terminal of the intelligent control terminal is connected to the current signal acquisition terminal through the B-phase CT signal bus, and the voltage transformer PT B1 One end is connected to the output terminal of the B-phase power switch, and the voltage transformer PT B1 One end of the voltage transformer PT is also grounded. B1 The other end is connected to the voltage signal acquisition end of the intelligent control terminal through the B-phase PT signal bus; the B-phase power switch output terminal 2 includes a voltage transformer PT B2 and current transformer CT B2 , where the current transformer CT B2 The second power supply terminal is connected to the power supply current B phase incoming line terminal, the current transformer CT B2 The current signal bus terminal of the intelligent control terminal is connected to the current signal acquisition terminal through the B-phase CT signal bus, and the voltage transformer PT B2 One end is connected to the output terminal of the B-phase power switch, and the voltage transformer PT B2 One end of the voltage transformer PT is also grounded. B2 The other end is connected to the voltage signal acquisition end of the intelligent control terminal through the B-phase PT signal bus; the B-phase power switch output terminal 3 includes a voltage transformer PT B3 and current transformer CT B3 , where the current transformer CT B3 The second power supply terminal is connected to the power supply current B phase incoming line terminal, the current transformer CT B3 The current signal bus terminal of the intelligent control terminal is connected to the current signal acquisition terminal through the B-phase CT signal bus, and the voltage transformer PT B3 One end is connected to the output terminal of the B-phase power switch, and the voltage transformer PT B3 One end of the voltage transformer PT is also grounded. B3The other end is connected to the voltage signal acquisition end of the intelligent control terminal through the B-phase PT signal bus; the B-phase power switch output terminal 4 includes a voltage transformer PT B4 and current transformer CT B4 , where the current transformer CT B4 The second power supply terminal is connected to the power supply current B phase incoming line terminal, the current transformer CT B4 The current signal bus terminal of the intelligent control terminal is connected to the current signal acquisition terminal through the B-phase CT signal bus, and the voltage transformer PT B4 One end is connected to the output terminal of the B-phase power switch, and the voltage transformer PT B4 One end of the voltage transformer PT is also grounded. B4 The other end of the B-phase power switch output terminal n includes the voltage transformer PT Bn and current transformer CT Bn , where the current transformer CT Bn The second power supply terminal is connected to the power supply current B phase incoming line terminal, the current transformer CT Bn The current signal bus terminal of the intelligent control terminal is connected to the current signal acquisition terminal through the B-phase CT signal bus, and the voltage transformer PT Bn One end is connected to the output terminal of the B-phase power switch, and the voltage transformer PT Bn One end of the voltage transformer PT is also grounded. Bn The other end is connected to the voltage signal acquisition end of the intelligent control terminal through the B-phase PT signal bus, and n depends on the number of power switch output terminals (electrical equipment).

[0053] The secondary system circuit of the output terminal 1 of the C phase power switch includes a voltage transformer PT C1 and current transformer CT C1 , where the current transformer CT C1 The second power supply terminal is connected to the power supply current C phase incoming line terminal, the current transformer CT C1 The current signal bus terminal is connected to the current signal acquisition terminal of the intelligent control terminal through the C-phase CT signal bus, and the voltage transformer PT C1 One end is connected to the output terminal of the C-phase power switch, and the voltage transformer PT C1 One end of the voltage transformer PT is also grounded. C1 The other end is connected to the voltage signal acquisition end of the intelligent control terminal through the C-phase PT signal bus; the C-phase power switch output terminal 2 includes a voltage transformer PT C2 and current transformer CT C2 , where the current transformer CT C2 The second power supply terminal is connected to the power supply current C phase incoming line terminal, the current transformer CT C2The current signal bus terminal is connected to the current signal acquisition terminal of the intelligent control terminal through the C-phase CT signal bus, and the voltage transformer PT C2 One end is connected to the output terminal of the C-phase power switch, and the voltage transformer PT C2 One end of the voltage transformer PT is also grounded. C2 The other end is connected to the voltage signal acquisition end of the intelligent control terminal through the C-phase PT signal bus; the C-phase power switch output terminal 3 includes a voltage transformer PT C3 and current transformer CT C3 , where the current transformer CT C3 The second power supply terminal is connected to the power supply current C phase incoming line terminal, the current transformer CT C3 The current signal bus terminal is connected to the current signal acquisition terminal of the intelligent control terminal through the C-phase CT signal bus, and the voltage transformer PT C3 One end is connected to the output terminal of the C-phase power switch, and the voltage transformer PT C3 One end of the voltage transformer PT is also grounded. C3 The other end is connected to the voltage signal acquisition end of the intelligent control terminal through the C-phase PT signal bus; the C-phase power switch output terminal 4 includes a voltage transformer PT C4 and current transformer CT C4 , where the current transformer CT C4 The second power supply terminal is connected to the power supply current C phase incoming line terminal, the current transformer CT C4 The current signal bus terminal is connected to the current signal acquisition terminal of the intelligent control terminal through the C-phase CT signal bus, and the voltage transformer PT C4 One end is connected to the output terminal of the C-phase power switch, and the voltage transformer PT C4 One end of the voltage transformer PT is also grounded. C4 The other end is connected to the voltage signal acquisition end of the intelligent control terminal through the C-phase PT signal bus; by analogy, the output terminal n of the C-phase power switch includes the voltage transformer PT Cn and current transformer CT Cn , where the current transformer CT Cn The second power supply terminal is connected to the power supply current C phase incoming line terminal, the current transformer CT Cn The current signal bus terminal is connected to the current signal acquisition terminal of the intelligent control terminal through the C-phase CT signal bus, and the voltage transformer PT Cn One end is connected to the output terminal of the C-phase power switch, and the voltage transformer PT Cn One end of the voltage transformer PT is also grounded. Cn The other end is connected to the voltage signal acquisition end of the intelligent control terminal through the C-phase PT signal bus, and n depends on the number of power switch output terminals (electrical equipment).

[0054] It should be noted that all current transformers of phase A share an A-phase current signal bus (A-phase CT signal bus), all current transformers of phase B share a B-phase current signal bus (B-phase CT signal bus), and all current transformers of phase C share a C-phase current signal bus (C-phase CT signal bus); all voltage transformers of phase A share an A-phase voltage signal bus (A-phase PT signal bus), all voltage transformers of phase B share a B-phase voltage signal bus (B-phase PT signal bus), and all voltage transformers of phase C share a C-phase voltage signal bus (C-phase PT signal bus), and all voltage signal buses and current signal buses share an intelligent control terminal.

[0055] like Figure 3 As shown, in the above technical solution, the fault pre-reclosing circuit of the output terminal 1 of the A-phase power switch includes a current transformer CT A 、IGBT A1 , low voltage fuse FU A0 and current limiting reactor LA A , among which, low voltage fuse FU A0 One end of the current transformer CT A The first power supply terminal, current transformer CT A The second power supply terminal is connected to the power supply current A phase incoming line terminal, the current transformer CT A The current signal bus terminal is connected to the current signal acquisition terminal of the intelligent control terminal through the A-phase CT signal bus, and the low-voltage fuse FU A0 The other end is connected to the current limiting reactor LA A At one end, the current limiting reactor LA A The other end is connected to the IGBT A1 The emitter of IGBT A1 The collector of the voltage transformer PT is connected A1 The other end of the IGBT A1 The gate is connected to the driving circuit.

[0056] like Figure 1 As shown, the fault pre-reclosing circuit of the output terminal 2 of the A-phase power switch includes a current transformer CT A 、IGBT A2 , low voltage fuse FU A0 and current limiting reactor LA A , among which, low voltage fuse FU A0 One end of the current transformer CT A The first power supply terminal, current transformer CT A The second power supply terminal is connected to the power supply current A phase incoming line terminal, the current transformer CT AThe current signal bus terminal is connected to the current signal acquisition terminal of the intelligent control terminal through the A-phase CT signal bus, and the low-voltage fuse FU A0 The other end is connected to the current limiting reactor LA A At one end, the current limiting reactor LA A The other end is connected to the IGBT A2 The emitter of IGBT A2 The collector of the voltage transformer PT is connected A2 The other end of the IGBT A2 The gate is connected to the drive circuit; the fault pre-reclosing circuit of the output terminal 3 of the A-phase power switch includes a current transformer CT A 、IGBT A3 , low voltage fuse FU A0 and current limiting reactor LA A , among which, low voltage fuse FU A0 One end of the current transformer CT A The first power supply terminal, current transformer CT A The second power supply terminal is connected to the power supply current A phase incoming line terminal, the current transformer CT A The current signal bus terminal is connected to the current signal acquisition terminal of the intelligent control terminal through the A-phase CT signal bus, and the low-voltage fuse FU A0 The other end is connected to the current limiting reactor LA A At one end, the current limiting reactor LA A The other end is connected to the IGBT A3 The emitter of IGBT A3 The collector of the voltage transformer PT is connected A3 The other end of the IGBT A3 The gate is connected to the drive circuit; the fault pre-reclosing circuit of the output terminal 4 of the A-phase power switch includes a current transformer CT A 、IGBT A4 , low voltage fuse FU A0 and current limiting reactor LA A , among which, low voltage fuse FU A0 One end of the current transformer CT A The first power supply terminal, current transformer CT A The second power supply terminal is connected to the power supply current A phase incoming line terminal, the current transformer CT A The current signal bus terminal is connected to the current signal acquisition terminal of the intelligent control terminal through the A-phase CT signal bus, and the low-voltage fuse FU A0 The other end is connected to the current limiting reactor LA A At one end, the current limiting reactor LA A The other end is connected to the IGBT A4 The emitter of IGBT A4The collector of the voltage transformer PT is connected A4 The other end of the IGBT A4 The gate of the A-phase power switch is connected to the drive circuit; by analogy, the fault pre-reclosing circuit of the output terminal n of the A-phase power switch includes the current transformer CT A 、IGBT An , low voltage fuse FU A0 and current limiting reactor LA A , among which, low voltage fuse FU A0 One end of the current transformer CT A The first power supply terminal, current transformer CT A The second power supply terminal is connected to the power supply current A phase incoming line terminal, the current transformer CT A The current signal bus terminal is connected to the current signal acquisition terminal of the intelligent control terminal through the A-phase CT signal bus, and the low-voltage fuse FU A0 The other end is connected to the current limiting reactor LA A At one end, the current limiting reactor LA A The other end is connected to the IGBT An The emitter of IGBT An The collector of the voltage transformer PT is connected An The other end of the IGBT An The gate is connected to the drive circuit, and n depends on the number of output terminals (electrical equipment) of the power switch.

[0057] like Figure 1 As shown, the fault pre-reclosing circuit of the output terminal 1 of the B-phase power switch includes a current transformer CT B 、IGBT B1 , low voltage fuse FU B0 and current limiting reactor LA B , among which, low voltage fuse FU B0 One end of the current transformer CT B The first power supply terminal, current transformer CT B The second power supply terminal is connected to the power supply current B phase incoming line terminal, the current transformer CT B The current signal bus terminal is connected to the current signal acquisition terminal of the intelligent control terminal through the B-phase CT signal bus, and the low-voltage fuse FU B0 The other end is connected to the current limiting reactor LA B At one end, the current limiting reactor LA B The other end is connected to the IGBT B1 The emitter of IGBT B1 The collector of the voltage transformer PT is connected B1 The other end of the IGBT B1The gate of the B-phase power switch is connected to the drive circuit. The fault pre-closing circuit of the output terminal 2 of the B-phase power switch includes a current transformer CT B 、IGBT B2 , low voltage fuse FU B0 and current limiting reactor LA B , among which, low voltage fuse FU B0 One end of the current transformer CT B The first power supply terminal, current transformer CT B The second power supply terminal is connected to the power supply current B phase incoming line terminal, the current transformer CT B The current signal bus terminal is connected to the current signal acquisition terminal of the intelligent control terminal through the B-phase CT signal bus, and the low-voltage fuse FU B0 The other end is connected to the current limiting reactor LA B At one end, the current limiting reactor LA B The other end is connected to the IGBT B2 The emitter of IGBT B2 The collector of the voltage transformer PT is connected B2 The other end of the IGBT B2 The gate of the B-phase power switch is connected to the drive circuit; the fault pre-reclosing circuit of the output terminal 3 includes a current transformer CT B 、IGBT B3 , low voltage fuse FU B0 and current limiting reactor LA B , among which, low voltage fuse FU B0 One end of the current transformer CT B The first power supply terminal, current transformer CT B The second power supply terminal is connected to the power supply current B phase incoming line terminal, the current transformer CT B The current signal bus terminal is connected to the current signal acquisition terminal of the intelligent control terminal through the B-phase CT signal bus, and the low-voltage fuse FU B0 The other end is connected to the current limiting reactor LA B At one end, the current limiting reactor LA B The other end is connected to the IGBT B3 The emitter of IGBT B3 The collector of the voltage transformer PT is connected B3 The other end of the IGBT B3 The gate is connected to the drive circuit; the fault pre-reclosing circuit of the B-phase power switch output terminal 4 includes a current transformer CT B 、IGBT B4 , low voltage fuse FU B0 and current limiting reactor LA B , among which, low voltage fuse FU B0 One end of the current transformer CTB The first power supply terminal, current transformer CT B The second power supply terminal is connected to the power supply current B phase incoming line terminal, the current transformer CT B The current signal bus terminal is connected to the current signal acquisition terminal of the intelligent control terminal through the B-phase CT signal bus, and the low-voltage fuse FU B0 The other end is connected to the current limiting reactor LA B At one end, the current limiting reactor LA B The other end is connected to the IGBT B4 The emitter of IGBT B4 The collector of the voltage transformer PT is connected B4 The other end of the IGBT B4 The gate of the B-phase power switch is connected to the drive circuit; by analogy, the fault pre-reclosing circuit of the output terminal n of the B-phase power switch includes a current transformer CT B 、IGBT Bn , low voltage fuse FU B0 and current limiting reactor LA B , among which, low voltage fuse FU B0 One end of the current transformer CT B The first power supply terminal, current transformer CT B The second power supply terminal is connected to the power supply current B phase incoming line terminal, the current transformer CT B The current signal bus terminal is connected to the current signal acquisition terminal of the intelligent control terminal through the B-phase CT signal bus, and the low-voltage fuse FU B0 The other end is connected to the current limiting reactor LA B At one end, the current limiting reactor LA B The other end is connected to the IGBT Bn The emitter of IGBT Bn The collector of the voltage transformer PT is connected Bn The other end of the IGBT Bn The gate is connected to the drive circuit, and n depends on the number of output terminals (electrical equipment) of the power switch.

[0058] The fault pre-reclosing circuit of the output terminal 1 of the C phase power switch includes a current transformer CT C 、IGBT C1 , low voltage fuse FU C0 and current limiting reactor LA C , among which, low voltage fuse FU C0 One end of the current transformer CT C The first power supply terminal, current transformer CT C The second power supply terminal is connected to the power supply current C phase incoming line terminal, the current transformer CT CThe current signal bus terminal is connected to the current signal acquisition terminal of the intelligent control terminal through the C-phase CT signal bus, and the low-voltage fuse FU C0 The other end is connected to the current limiting reactor LA C At one end, the current limiting reactor LA C The other end is connected to the IGBT C1 The emitter of IGBT C1 The collector of the voltage transformer PT is connected C1 The other end of the IGBT C1 The gate of the C phase power switch is connected to the drive circuit. The fault pre-closing circuit of the output terminal 2 includes a current transformer CT C 、IGBT C2 , low voltage fuse FU C0 and current limiting reactor LA C , among which, low voltage fuse FU C0 One end of the current transformer CT C The first power supply terminal, current transformer CT C The second power supply terminal is connected to the power supply current C phase incoming line terminal, the current transformer CT C The current signal bus terminal is connected to the current signal acquisition terminal of the intelligent control terminal through the C-phase CT signal bus, and the low-voltage fuse FU C0 The other end is connected to the current limiting reactor LA C At one end, the current limiting reactor LA C The other end is connected to the IGBT C2 The emitter of IGBT C2 The collector of the voltage transformer PT is connected C2 The other end of the IGBT C2 The gate of the C phase power switch is connected to the drive circuit; the fault pre-reclosing circuit of the output terminal 3 includes a current transformer CT C 、IGBT C3 , low voltage fuse FU C0 and current limiting reactor LA C , among which, low voltage fuse FU C0 One end of the current transformer CT C The first power supply terminal, current transformer CT C The second power supply terminal is connected to the power supply current C phase incoming line terminal, the current transformer CT C The current signal bus terminal is connected to the current signal acquisition terminal of the intelligent control terminal through the C-phase CT signal bus, and the low-voltage fuse FU C0 The other end is connected to the current limiting reactor LA C At one end, the current limiting reactor LA C The other end is connected to the IGBT C3 The emitter of IGBT C3The collector of the voltage transformer PT is connected C3 The other end of the IGBT C3 The gate is connected to the drive circuit; the fault pre-reclosing circuit of the C phase power switch output terminal 4 includes a current transformer CT C 、IGBT C4 , low voltage fuse FU C0 and current limiting reactor LA C , among which, low voltage fuse FU C0 One end of the current transformer CT C The first power supply terminal, current transformer CT C The second power supply terminal is connected to the power supply current C phase incoming line terminal, the current transformer CT C The current signal bus terminal is connected to the current signal acquisition terminal of the intelligent control terminal through the C-phase CT signal bus, and the low-voltage fuse FU C0 The other end is connected to the current limiting reactor LA C At one end, the current limiting reactor LA C The other end is connected to the IGBT C4 The emitter of IGBT C4 The collector of the voltage transformer PT is connected C4 The other end of the IGBT C4 The gate of the C-phase power switch is connected to the drive circuit; by analogy, the fault pre-reclosing circuit of the output terminal n of the C-phase power switch includes a current transformer CT C 、IGBT Cn , low voltage fuse FU C0 and current limiting reactor LA C , among which, low voltage fuse FU C0 One end of the current transformer CT C The first power supply terminal, current transformer CT C The second power supply terminal is connected to the power supply current C phase incoming line terminal, the current transformer CT C The current signal bus terminal is connected to the current signal acquisition terminal of the intelligent control terminal through the C-phase CT signal bus, and the low-voltage fuse FU C0 The other end is connected to the current limiting reactor LA C At one end, the current limiting reactor LA C The other end is connected to the IGBT Cn The emitter of IGBT Cn The collector of the voltage transformer PT is connected Cn The other end of the IGBT Cn The gate is connected to the drive circuit, and n depends on the number of output terminals (electrical equipment) of the power switch.

[0059] It should be noted that Figure 1 Current transformer CT in AWith voltage transformer PT A , current transformer CT B With voltage transformer PT B And current transformer CT C With voltage transformer PT C As part of the secondary circuit system, the voltage and current information of the A-phase fault pre-reclosing circuit, the voltage and current information of the B-phase fault pre-reclosing circuit, and the voltage and current information of the C-phase fault pre-reclosing circuit in the three-phase power supply are collected respectively, and transmitted to the intelligent control terminal through the voltage and current signal bus. The low-voltage fuse of the fault pre-reclosing circuit is mainly used to quickly cut off the circuit when the short-circuit current is higher than the selective limit current. However, its action has a certain delay, and it cannot immediately limit the current in the early stage of the rapid rise of the short-circuit current. The current-limiting reactor can quickly limit the rate of rise of the current at the moment of the short circuit and reduce the peak value of the short-circuit current. For example, when a short-circuit fault occurs suddenly at the output end of the power switch and the short-circuit current increases sharply, the current-limiting reactor can suppress the current in the first time, buy time for the low-voltage fuse to act, and reduce the impact of the short-circuit current on the equipment in the circuit.

[0060] In the above technical scheme, the method for the intelligent control terminal to control the on and off of the IGBT and the low-voltage circuit breaker according to the voltage and current information of the power switch outlet terminal includes: the current transformer and the voltage transformer transmit the collected voltage and current information of the power switch outlet terminal to the intelligent control terminal, and the intelligent control terminal compares the collected voltage value and current value of the power switch outlet terminal with the normal current value and voltage value. When the collected voltage value and current value of the power switch outlet terminal suddenly change and exceed the normal working range, it means that the power switch outlet terminal fails. The intelligent control terminal transmits the collected voltage and current information of the power switch outlet terminal to the intelligent control terminal through the CT signal bus and the PT signal bus. Send control instructions to control the IGBT to turn on, the low-voltage circuit breaker to disconnect, the low-voltage switch main circuit to cut off the power, and the fault pre-reclosing circuit to start working. The voltage and current information of the low-voltage switch main circuit and the fault pre-reclosing circuit are continuously collected through the current transformer and the voltage transformer. The type of fault and whether the fault is relieved are determined based on the voltage and current information of the low-voltage switch main circuit and the fault pre-reclosing circuit. If the fault is a transient fault, when the transient fault is relieved, the intelligent control terminal sends a control instruction again to control the IGBT to disconnect, the low-voltage circuit breaker to turn on, the low-voltage switch main circuit to resume normal operation, and the fault pre-reclosing circuit to cut off the power.

[0061] Take the fault of output terminal 1 of phase A power switch as an example: During the normal operation phase, the main circuit of the low-voltage switch (such as Figure 2 As shown in the figure, the power supply current path is formed, and the current at the A-phase incoming line end passes through the low-voltage fuse FU in turn. A1 , low voltage circuit breaker QF A1 Delivered to the A-phase power switch output terminal 1; secondary system circuit (such as Figure 4 The intelligent control terminal shown in the figure is based on the voltage transformer PTA1 and current transformer CT A1 The normal voltage and current of the low-voltage switch main circuit are collected, and the adjustment signal is sent to the fault pre-reclosing circuit (such as Figure 3 As shown), control IGBT A1 Disconnected, no current flows through the fault pre-reclosing circuit.

[0062] During the fault phase, the low voltage circuit breaker QF A1 Disconnect, no current flows through the main circuit of the low-voltage switch; the intelligent control terminal of the secondary system circuit is based on the voltage transformer PT A1 and current transformer CT A1 The fault voltage and fault current signals of the low-voltage switch main circuit are collected, and the adjustment signal is sent to the fault pre-reclosing circuit to control the IGBT A1 Closed, the current at the A-phase incoming line passes through the low-voltage fuse FU in turn. A0 , Current limiting reactor LA A and IGBT A1 Delivered to the A-phase power switch output terminal 1.

[0063] During the switch reclosing phase, the intelligent control terminal of the secondary system circuit is based on the voltage transformer PT A and current transformer CT A The voltage and current signals collected from the fault pre-reclosing circuit determine that the fault at the output terminal 1 of the phase A power switch is cleared, and an adjustment signal is sent to the low-voltage switch main circuit to control the low-voltage circuit breaker QF A1 Closed, the current at the A-phase incoming line passes through the low-voltage fuse FU in turn. A1 , low voltage circuit breaker QF A1 Delivered to the A-phase power switch output terminal 1.

[0064] Example 2

[0065] The low-voltage switch short-circuit protection and fault detection method of the IGBT-based low-voltage switch short-circuit protection and fault detection circuit comprises:

[0066] The voltage and current information of the output terminal of the power switch is collected through the voltage transformer and the current transformer, and according to the collected voltage and current information of the output terminal of the power switch, whether the output terminal of the power switch has a fault is judged, and if there is a fault at the output terminal of the power switch, the fault type is judged;

[0067] When there is no fault at the power switch outlet, the power supply current is transmitted to the power switch outlet. When there is a fault at the power switch outlet, the main circuit of the low-voltage switch is disconnected, and the power supply current is stopped from being transmitted to the power switch outlet.

[0068] When the fault type at the output end of the power switch is a transient fault, the IGBT is controlled to be turned on so that the power current bypasses the circuit breaker and fuse of the low-voltage switch main circuit and is transmitted to the output end of the power switch. After the transient fault is eliminated, the IGBT is controlled to be disconnected so that the power current is transmitted to the output end of the power switch again through the low-voltage switch main circuit.

[0069] The contents not described in detail in this specification belong to the prior art known to professional and technical personnel in this field.

Claims

1. A low voltage switch short circuit protection and fault detection circuit based on IGBT, characterized in that: It includes: Low-voltage switch main circuit, fault detection module, and outgoing line fault pre-reclosing module; The fault detection module is used to collect voltage and current information of the power switch output terminal through a voltage transformer and a current transformer, and judge whether there is a fault at the power switch output terminal according to the collected voltage and current information at the power switch output terminal, and judge the fault type when there is a fault at the power switch output terminal; The main circuit of the low-voltage switch is used to transmit the current of the power supply to the output terminal of the power switch when there is no fault at the output terminal of the power switch. When there is a fault at the output terminal of the power switch, the main circuit of the low-voltage switch is disconnected and stops transmitting the power current to the output terminal of the power switch; The output terminal fault pre-reclosing module is used to control the IGBT to turn on when the fault type at the output terminal of the power switch is a transient fault, so that the power current bypasses the circuit breaker and fuse of the low-voltage switch main circuit and is transmitted to the output terminal of the power switch. After the transient fault is relieved, the IGBT is controlled to be disconnected, so that the power current is transmitted to the output terminal of the power switch through the low-voltage switch main circuit again.

2. The IGBT-based low-voltage switch short-circuit protection and fault detection circuit according to claim 1, characterized in that: The collected voltage and current information of the power switch output terminal is transmitted to the intelligent control terminal through the signal bus of the secondary system loop. The intelligent control terminal controls the conduction and disconnection of the IGBT and the low-voltage circuit breaker according to the voltage and current information of the power switch output terminal.

3. The IGBT-based low-voltage switch short-circuit protection and fault detection circuit according to claim 1, characterized in that: The low-voltage circuit breaker is used to automatically disconnect when a fault occurs at the outlet of the power switch and the short-circuit current is lower than the selective limit current, so that the current cannot be transmitted to the outlet through the low-voltage fuse and low-voltage circuit breaker of the main circuit of the low-voltage switch; The low-voltage fuse is used to automatically disconnect when a fault occurs at the output end of the power switch and the short-circuit current is higher than the selective limit current, so that the current cannot be transmitted to the output line through the low-voltage fuse and low-voltage circuit breaker of the low-voltage switch main circuit.

4. The IGBT-based low-voltage switch short-circuit protection and fault detection circuit according to claim 1, characterized in that: The IGBT is controlled by an intelligent control terminal. When a fault occurs at the output end of the power switch, the intelligent control terminal controls the IGBT to be turned on, and the power current is transmitted to the output end of the power switch through the fault pre-reclosing circuit where the IGBT is located. When the instantaneous fault at the output end of the power switch is removed, the intelligent control terminal controls the IGBT to be disconnected, so that the power current cannot be transmitted to the output end of the power switch through the fault pre-reclosing circuit where the IGBT is located, and the power current is transmitted to the output end of the power switch again through the low-voltage switch main circuit.

5. The IGBT-based low-voltage switch short-circuit protection and fault detection circuit according to claim 1, characterized in that: The voltage transformer is used to collect voltage information of the fault pre-reclosing circuit and the main circuit of the low-voltage switch, and the current transformer is used to collect current information of the fault pre-reclosing circuit and the main circuit of the low-voltage switch.

6. The IGBT-based low-voltage switch short-circuit protection and fault detection circuit according to claim 1, characterized in that: The low-voltage switch main circuit includes a low-voltage fuse FU A1 And low voltage circuit breaker QF A1 , among which, low voltage fuse FU A1 One end of the current transformer CT A1 The first power terminal, low voltage fuse FU A1 The other end is connected to the low voltage circuit breaker QF A1 One end of the low voltage circuit breaker QF A1 The other end is connected to the voltage transformer PT A1 One end of the low voltage circuit breaker QF A1 The other end is the power switch outlet.

7. The IGBT-based low-voltage switch short-circuit protection and fault detection circuit according to claim 6, characterized in that: The secondary system loop includes a voltage transformer PT A1 and current transformer CT A1 , where the current transformer CT A1 The second power supply terminal is connected to the power supply current A phase incoming line terminal, the current transformer CT A1 The current signal bus terminal is connected to the current signal acquisition terminal of the intelligent control terminal through the A-phase CT signal bus, and the voltage transformer PT A1 One end is connected to the output terminal of the A-phase power switch, and the voltage transformer PT A1 One end of the voltage transformer PT is also grounded. A1 The other end is connected to the voltage signal acquisition end of the intelligent control terminal through the A-phase PT signal bus.

8. The IGBT-based low-voltage switch short-circuit protection and fault detection circuit according to claim 2 or 5, characterized in that: The fault pre-reclosing circuit includes a current transformer CT A 、IGBT A1 , low voltage fuse FU A0 and current limiting reactor LA A , among which, low voltage fuse FU A0 One end of the current transformer CT A The first power supply terminal, current transformer CT A The second power supply terminal is connected to the power supply current A phase incoming line terminal, the current transformer CT A The current signal bus terminal is connected to the current signal acquisition terminal of the intelligent control terminal through the A-phase CT signal bus, and the low-voltage fuse FU A0 The other end is connected to the current limiting reactor LA A At one end, the current limiting reactor LA A The other end is connected to the IGBT A1 The emitter of IGBT A1 The collector of the voltage transformer PT is connected A1 The other end of the IGBT A1 The gate is connected to the driving circuit.

9. The IGBT-based low-voltage switch short-circuit protection and fault detection circuit according to claim 2, characterized in that: The method for the intelligent control terminal to control the on and off of the IGBT and the low-voltage circuit breaker according to the voltage and current information of the power switch outlet terminal includes: the current transformer and the voltage transformer transmit the collected voltage and current information of the power switch outlet terminal to the intelligent control terminal, and the intelligent control terminal compares the collected voltage value and current value of the power switch outlet terminal with the normal current value and voltage value. When the collected voltage value and current value of the power switch outlet terminal suddenly change and exceed the normal working range, it means that the power switch outlet terminal fails, and the intelligent control terminal sends a control signal through the CT signal bus and the PT signal bus. The control terminal sends a control command to control the IGBT to turn on, the low-voltage circuit breaker to disconnect, the low-voltage switch main circuit to cut off the power, and the fault pre-reclosing circuit to start working. The voltage and current information of the low-voltage switch main circuit and the fault pre-reclosing circuit are continuously collected through the current transformer and the voltage transformer. The type of fault and whether the fault is relieved are determined according to the voltage and current information of the low-voltage switch main circuit and the fault pre-reclosing circuit. If the fault is a transient fault, after the transient fault is relieved, the intelligent control terminal sends a control command again to control the IGBT to disconnect, the low-voltage circuit breaker to turn on, the low-voltage switch main circuit to resume normal operation, and the fault pre-reclosing circuit to cut off the power.

10. A low-voltage switch short-circuit protection and fault detection method of the IGBT-based low-voltage switch short-circuit protection and fault detection circuit according to claim 1, characterized in that: It includes: The voltage and current information of the output terminal of the power switch is collected through the voltage transformer and the current transformer, and according to the collected voltage and current information of the output terminal of the power switch, whether the output terminal of the power switch has a fault is judged, and if there is a fault at the output terminal of the power switch, the fault type is judged; When there is no fault at the power switch outlet, the power supply current is transmitted to the power switch outlet. When there is a fault at the power switch outlet, the main circuit of the low-voltage switch is disconnected, and the power supply current is stopped from being transmitted to the power switch outlet. When the fault type at the output end of the power switch is a transient fault, the IGBT is controlled to be turned on so that the power current bypasses the circuit breaker and fuse of the low-voltage switch main circuit and is transmitted to the output end of the power switch. After the transient fault is eliminated, the IGBT is controlled to be disconnected so that the power current is transmitted to the output end of the power switch again through the low-voltage switch main circuit.

Images