Circuit breaker phase selection opening and closing device and method

Abstract

The invention discloses a circuit breaker phase selection opening and closing device and method, and relates to the field of phase selection control. According to the scheme, a phase selection control system, an opening device and a closing device are additionally arranged on a high-voltage transmission line of an original railway vehicle, and the phase selection control system adopts a phase selection opening and closing technology to control closing and opening of the opening device and the closing device; in addition, when the phase selection control system breaks down, the closing device is in a closed state and transmits an opening and closing instruction to a coil of the vacuum circuit breaker, so that the vacuum circuit breaker carries out corresponding opening and closing according to the opening and closing instruction. According to the scheme, the problems of closing inrush current and opening overvoltage of the vacuum circuit breaker are effectively avoided through a phase selection opening and closing technology when the phase selection control system does not have a fault, and the vacuum circuit breaker can be enabled to perform corresponding opening and closing according to an existing mode, namely according to an opening and closing instruction, when the phase selection control system has a fault; and the reliability of the scheme is greatly improved.

Description

Technical Field

[0001] The present invention relates to the field of phase selection control, and in particular to a circuit breaker phase selection switching device and method. Background Art

[0002] Phase selection and separation technology first appeared in the 1970s. Its essence is to control the switch equipment to complete the closing or opening at the optimal electrical angle of voltage or current according to the characteristics of different loads (such as parallel capacitor banks, overhead transmission lines, no-load transformers, etc.), so as to achieve a smooth transition without impact, and effectively weaken the transient electromagnetic effect of the switch. Since the technology was put into practical use, the number and scope of its use in the European and American markets have expanded rapidly, from only controlling the input of capacitors at the beginning to a variety of uses. This technology is of great significance for improving the quality of power and the life of switches, and is a frontier topic of electrical intelligence. Since 1998, China has adopted phase selection and separation technology on circuit breakers for high-voltage transmission lines to suppress closing inrush current and operating overvoltage.

[0003] However, to date, the vacuum circuit breakers for rail vehicles around the world have not adopted the phase-selective separation and combination technology. An important reason is that rail vehicles are mobile equipment, and vacuum circuit breakers are vehicle protection equipment. The operating environment in rail vehicles is complex, and various internal and external electromagnetic interferences are numerous and uncontrollable. The application of phase-selective separation and combination technology must increase the phase selection control system. At this time, if the phase selection control system fails, it will cause the vacuum circuit breaker to fail, which will inevitably reduce the reliability of the rail vehicle's high-voltage system and affect driving safety. Summary of the invention

[0004] The object of the present invention is to provide a circuit breaker phase selection and opening and closing device and method. This scheme adds a phase selection control system, an opening device and a closing device to the original high-voltage transmission line of a rail vehicle, which not only ensures that the closing surge current and opening overvoltage problems of the vacuum circuit breaker can be effectively avoided through the phase selection and opening technology when the phase selection control system has not failed, but also enables the vacuum circuit breaker to perform corresponding opening and closing in the existing manner, that is, according to the opening and closing instructions when the phase selection control system fails, thereby greatly improving the reliability of the scheme.

[0005] In order to solve the above technical problems, the present invention provides a circuit breaker phase selection opening and closing device, comprising: a phase selection control system, an opening device, and a closing device;

[0006] The first end of the closing device is connected to the opening and closing instructions, and the second end is connected to the coil of the vacuum circuit breaker, and is used to close when the phase selection control system fails, and transmit the opening and closing instructions to the coil of the vacuum circuit breaker, and the opening and closing instructions include: closing instructions and opening instructions;

[0007] The first end of the opening device is connected to the power supply, and the second end is connected to the coil of the vacuum circuit breaker;

[0008] The input end of the phase selection control system is connected to the opening and closing instructions, and the output end is respectively connected to the control end of the closing device and the control end of the opening device, and is used to control the closing device and the opening device to open based on the received closing instruction, and to control the closing device to open and the opening device to close based on the received opening instruction.

[0009] Optionally, the closing device is a relay, a first end of the coil of the relay is connected to the output end of the phase selection control system, a second end of the coil of the relay is connected to the ground, the moving contact of the relay is connected to the opening and closing instructions, the normally closed contact of the relay is connected to the coil of the vacuum circuit breaker, and the normally open contact of the relay is suspended, and is used to control the moving contact of the relay to be connected to the normally open contact of the relay after the coil of the relay receives a first electrical signal output when the phase selection control system receives the closing instruction, and to control the moving contact of the relay to be connected to the normally open contact of the relay after the coil of the relay receives a second electrical signal output when the phase selection control system receives the opening instruction; when a fault occurs in the phase selection control system, the moving contact of the relay is connected to the normally closed contact of the relay.

[0010] Optionally, the opening device is a first N-type MOS tube, the gate of the first N-type MOS tube is connected to the output end of the phase selection control system, the drain of the first N-type MOS tube is connected to the power supply, and the source of the first N-type MOS tube is connected to the coil of the vacuum circuit breaker, and is used for turning on after receiving a first electrical signal output when the phase selection control system receives the opening instruction, and turning off after receiving a second electrical signal output when the phase selection control system receives the closing instruction.

[0011] Optionally, the closing device is a second N-type MOS tube, the gate of the second N-type MOS tube is connected to the output end of the phase selection control system, the drain of the second N-type MOS tube is connected to the opening and closing instruction, and the source of the second N-type MOS tube is connected to the coil of the vacuum circuit breaker, and is used for shutting down after the coil of the relay receives a first electrical signal output after the phase selection control system receives the closing instruction, and shutting down after the coil of the relay receives a second electrical signal output after the phase selection control system receives the opening instruction;

[0012] The circuit breaker phase selection and switching device further comprises:

[0013] A state collector, which is connected to the phase selection control system and is used to obtain a state signal periodically sent by the phase selection control system;

[0014] A redundant control system, wherein a first input end of the redundant control system is connected to the opening and closing instructions, a second input end is connected to the status collector, and an output end is connected to the coil of the vacuum circuit breaker, and is used to send the opening and closing instructions to the vacuum circuit breaker when the status signal is not received within a preset time period.

[0015] Optionally, also include:

[0016] a first unidirectional conduction module, wherein an input end of the first unidirectional conduction module is connected to the power supply, and an output end of the first unidirectional conduction module is connected to a first end of the opening device;

[0017] A second one-way conducting module, wherein the input end of the second one-way conducting module is connected to the opening and closing instruction, and the output end is connected to the first end of the closing device.

[0018] Optionally, the opening device further includes:

[0019] A time delay relay, wherein the first end of the coil of the time delay relay is connected to the opening and closing instruction, the second end of the coil of the time delay relay is connected to the ground, the moving contact of the normally open contact of the time delay relay is connected to the power supply, and the static contact of the normally open contact of the time delay relay is connected to the first end of the opening device, and is used to close the moving contact and the static contact after a first preset time after receiving the opening instruction, and to disconnect the moving contact and the static contact after the first preset time after receiving the closing instruction.

[0020] In order to solve the above technical problems, the present invention also provides a circuit breaker phase selection opening and closing method, which is applied to the option control system in the above-mentioned circuit breaker phase selection opening and closing device, wherein the circuit breaker phase selection opening and closing device also includes: an opening device and a closing device; the first end of the closing device is connected to the opening and closing instruction, and the second end is connected to the coil of the vacuum circuit breaker; the first end of the opening device is connected to the power supply, and the third end is connected to the coil of the vacuum circuit breaker; the input end of the phase selection control system is connected to the opening and closing instruction, and the output end is respectively connected to the control end of the closing device and the control end of the opening device; the method comprises:

[0021] Obtaining a switch-on / off instruction, wherein the switch-on / off instruction includes a switch-on instruction and a switch-off instruction;

[0022] The closing device and the opening device are controlled to be opened based on the received closing instruction, and the closing device is controlled to be opened and the opening device is controlled to be closed based on the received opening instruction.

[0023] Optionally, controlling the closing device and the opening device to be opened based on the received closing instruction, and controlling the closing device to be opened and the opening device to be closed based on the received opening instruction, comprises:

[0024] Acquiring a voltage phase of the transformer in a first preset period, wherein the vacuum circuit breaker is connected to a power grid and the transformer respectively;

[0025] The moment when the voltage phase is a first preset voltage phase is used as the closing time, and the moment when the voltage phase is a second preset voltage phase is used as the opening time, wherein the first preset voltage phase indicates that the grid voltage received by the transformer is equal to the grid voltage peak value, and the second preset voltage phase indicates that the grid current received by the transformer is at the current zero crossing point;

[0026] At the closing time, a first signal is sent to the closing device and a second signal is sent to the opening device to control the closing device and the opening device to be opened; at the opening time, a third signal is sent to the closing device and a fourth signal is sent to the opening device to control the closing device to be opened and the opening device to be closed.

[0027] Optionally, after controlling the closing device and the opening device to be disconnected, the method further includes:

[0028] Determining whether the vacuum circuit breaker is in a closed state;

[0029] If the vacuum circuit breaker is in a closed state, delaying for a second preset time to obtain an average current value of the power grid within a second preset period;

[0030] The closing timing is adjusted according to the magnitude relationship between the current average value and the preset current range.

[0031] Optionally, adjusting the closing timing according to the magnitude relationship between the current average value and a preset current range includes:

[0032] If the current average value is greater than the maximum current value in the preset current range, it is determined that the magnetic flux of the transformer is forward saturated, and the closing timing is increased by a preset value;

[0033] If the current average value is less than the maximum current value in the preset current range, it is determined that the magnetic flux of the transformer is negatively saturated, and the closing timing is reduced by the preset value.

[0034] The object of the present invention is to provide a circuit breaker phase selection and opening and closing device and method. This scheme adds a phase selection control system, an opening device and a closing device to the original high-voltage transmission line of a rail vehicle. The phase selection control system adopts phase selection and opening technology to control the closing and disconnection of the opening device and the closing device, so as to select the appropriate time to control the opening and closing of the vacuum circuit breaker. In addition, when the phase selection control system fails, the closing device will be in a closed state, and the opening and closing instructions will be transmitted to the coil of the vacuum circuit breaker, so that the vacuum circuit breaker will perform corresponding opening and closing according to the opening and closing instructions. This scheme not only ensures that the closing surge current and opening overvoltage problems of the vacuum circuit breaker are effectively avoided through the phase selection and opening technology when the phase selection control system does not fail, but also allows the vacuum circuit breaker to perform corresponding opening and closing in the existing manner, that is, according to the opening and closing instructions when the phase selection control system fails, thereby greatly improving the reliability of the scheme. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0036] Figure 1 A schematic structural diagram of a circuit breaker phase selection and switching device provided by the present invention;

[0037] Figure 2 A schematic structural diagram of another circuit breaker phase selection and switching device provided by the present invention;

[0038] Figure 3 A schematic structural diagram of another circuit breaker phase selection and switching device provided by the present invention;

[0039] Figure 4 A process flow chart of a circuit breaker phase selection and separation method provided by the present invention;

[0040] Figure 5 A schematic diagram of the structure of a no-load closing circuit, a no-load closing transformer equivalent circuit and a no-load closing simplified circuit provided by the present invention;

[0041] Figure 6 A schematic diagram of an exciting current waveform of a transformer with unsaturated magnetic flux provided by the present invention;

[0042] Figure 7 A schematic diagram of a transformer magnetic flux saturation excitation current waveform provided by the present invention;

[0043] Figure 8The present invention provides a calibration block diagram for automatic time delay search for closing at the voltage positive peak value. DETAILED DESCRIPTION

[0044] The core of the present invention is to provide a circuit breaker phase selection and opening and closing device and method. This scheme adds a phase selection control system, an opening device and a closing device to the original high-voltage transmission line of the rail vehicle, which not only ensures that the closing surge current and opening overvoltage problems of the vacuum circuit breaker can be effectively avoided through the phase selection and opening technology when the phase selection control system has not failed, but also enables the vacuum circuit breaker to perform corresponding opening and closing in the existing manner, that is, according to the opening and closing instructions when the phase selection control system fails, thereby greatly improving the reliability of the scheme.

[0045] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0046] Please refer to Figure 1 , Figure 1 The schematic diagram of the structure of a circuit breaker phase selection and opening and closing device provided by the present invention. The circuit breaker phase selection and opening and closing device comprises: a phase selection control system 1, an opening device 2, and a closing device 3;

[0047] The first end of the closing device 3 is connected to the opening and closing instructions, and the second end is connected to the coil of the vacuum circuit breaker, and is used to close when a fault occurs in the phase selection control system 1, and transmit the opening and closing instructions to the coil of the vacuum circuit breaker. The opening and closing instructions include: closing instructions and opening instructions;

[0048] The first end of the opening device 2 is connected to the power supply, and the second end is connected to the coil of the vacuum circuit breaker;

[0049] The input end of the phase selection control system 1 is connected to the opening and closing instructions, and the output end is connected to the control end of the closing device 3 and the control end of the opening device 2 respectively, for controlling the closing device 3 and the opening device 2 to open based on the received closing instruction, and controlling the closing device 3 to open and the opening device 2 to close based on the received opening instruction.

[0050] In the present invention, considering that the vacuum circuit breaker on the high-voltage line of the rail vehicle in the prior art has not applied the phase selection and opening technology, the present solution adds a phase selection control system 1, an opening device 2, and a closing device 3 for the vacuum circuit breaker. When the phase selection control system 1 does not fail, the phase selection control system 1 will control the closing device 3 and the opening device 2 to be disconnected at an appropriate time based on the phase selection and opening technology after receiving the closing command. At this time, the coil of the vacuum circuit breaker can neither receive the opening and closing command nor the electric energy transmitted by the power supply, and the vacuum circuit breaker is in a closed state; similarly, the phase selection control system 1 will control the closing device 3 to be disconnected and the opening device 2 to be closed at an appropriate time based on the phase selection and opening technology after receiving the opening command. In this case, the coil of the vacuum circuit breaker cannot receive the opening and closing instructions, but can receive the electric energy transmitted by the power supply, and the vacuum circuit breaker is in the opening state; in addition, when the phase selection control system 1 fails, the closing device 3 is closed at this time, and the opening and closing instructions are transmitted to the coil of the vacuum circuit breaker, so that the vacuum circuit breaker performs corresponding closing or opening in the existing manner, that is, according to the received opening and closing instructions. This ensures that the closing surge current and opening overvoltage problems of the vacuum circuit breaker can be effectively avoided through the phase selection opening and closing technology when the phase selection control system 1 does not fail, and also allows the vacuum circuit breaker to perform corresponding opening and closing in the existing manner, that is, according to the opening and closing instructions when the phase selection control system 1 fails, thereby greatly improving the reliability of the solution.

[0051] The present embodiment provides a circuit breaker phase selection and opening device. The present scheme adds a phase selection control system 1, an opening device 2 and a closing device 3 to the original high-voltage transmission line of the rail vehicle. The phase selection control system 1 adopts phase selection and opening technology to control the closing and disconnection of the opening device 2 and the closing device 3, so as to select the appropriate time to control the opening and closing of the vacuum circuit breaker. In addition, when the phase selection control system 1 fails, the closing device 3 is in a closed state, and the opening and closing instructions are transmitted to the coil of the vacuum circuit breaker, so that the vacuum circuit breaker performs corresponding opening and closing according to the opening and closing instructions. The present scheme not only ensures that the closing surge current and opening overvoltage problems of the vacuum circuit breaker are effectively avoided through the phase selection and opening technology when the phase selection control system 1 does not fail, but also allows the vacuum circuit breaker to perform corresponding opening and closing in the existing manner, that is, according to the opening and closing instructions when the phase selection control system 1 fails, thereby greatly improving the reliability of the scheme.

[0052] Based on the above embodiments:

[0053] As an optional embodiment, the closing device 3 is a relay, a first end of the coil of the relay is connected to the output end of the phase selection control system 1, a second end of the coil of the relay is connected to the ground, the moving contact of the relay is connected to the opening and closing instructions, the normally closed contact of the relay is connected to the coil of the vacuum circuit breaker, and the normally open contact of the relay is suspended, and is used to control the moving contact of the relay to be connected to the normally open contact of the relay after the coil of the relay receives the first electrical signal output by the phase selection control system 1 after receiving the closing instruction, and to control the moving contact of the relay to be connected to the normally open contact of the relay after the coil of the relay receives the second electrical signal output by the phase selection control system 1 after receiving the opening instruction, and when a fault occurs in the phase selection control system 1, the moving contact of the relay is connected to the normally closed contact of the relay.

[0054] In the present invention, in order to ensure that when the phase selection control system 1 fails, the closing device 3 can transmit the opening and closing instructions to the coil of the vacuum circuit breaker, the present scheme adopts a relay as the closing device 3, and utilizes the coil of the relay to connect the moving contact of the relay with the normally closed contact of the relay when no power is supplied, so that when the phase selection control system 1 fails, that is, the phase selection control system 1 cannot transmit an electrical signal to the coil of the relay, it can be ensured that the opening and closing instructions can be transmitted to the vacuum circuit breaker through the moving contact and normally closed contact of the relay, and when the phase selection control system 1 fails, the coil of the relay is connected to the moving contact and normally open contact of the relay through the electrical signal transmitted by the phase selection control system 1, ensuring that the vacuum circuit breaker is closed based on the phase selection opening and closing technology when the phase selection control system 1 is not controlled, avoiding the problem of closing inrush current, and when the phase selection control system 1 fails, the opening and closing instructions can be stably transmitted to the vacuum circuit breaker, allowing the vacuum circuit breaker to perform corresponding opening and closing in the existing manner, that is, according to the opening and closing instructions, thereby greatly improving the reliability of the scheme.

[0055] As an optional embodiment, the opening device 2 is a first N-type MOS tube, the gate of the first N-type MOS tube is connected to the output end of the phase selection control system 1, the drain of the first N-type MOS tube is connected to the power supply, and the source of the first N-type MOS tube is connected to the coil of the vacuum circuit breaker, and is used for turning on after receiving a first electrical signal output after the phase selection control system 1 receives an opening instruction, and turning off after receiving a second electrical signal output after the phase selection control system 1 receives a closing instruction.

[0056] In the present invention, considering that when the phase selection control system 1 is not faulty, when the phase selection control system 1 receives a closing command, it will control the opening device 2 to open, and vice versa, when the phase selection control system 1 receives an opening command, it will control the opening device 2 to close, so the opening device 2 only needs to be turned on or off accordingly according to the phase selection control system 1, and considering the cost of the entire circuit breaker phase selection and opening device, because MOS (Metal-Oxide-Semiconductor Field-EffectTransistor) tube has the characteristics of low power consumption, small size, low cost, high stability, fast response speed, etc., this scheme selects N-type MOS tube as the opening device 2.

[0057] As an optional embodiment, the closing device 3 is a second N-type MOS tube, the gate of the second N-type MOS tube is connected to the output end of the phase selection control system 1, the drain of the second N-type MOS tube is connected to the opening and closing instructions, and the source of the second N-type MOS tube is connected to the coil of the vacuum circuit breaker, and is used to shut down after the coil of the relay receives the first electrical signal output after the phase selection control system 1 receives the closing instruction, and shut down after the coil of the relay receives the second electrical signal output after the phase selection control system 1 receives the opening instruction;

[0058] The circuit breaker phase selection and closing device also includes:

[0059] A state collector, which is connected to the phase selection control system 1 and is used to obtain a state signal periodically sent by the phase selection control system 1;

[0060] A redundant control system, wherein the first input end of the redundant control system is connected to the opening and closing instructions, the second input end is connected to the status collector, and the output end is connected to the coil of the vacuum circuit breaker, and is used to send opening and closing instructions to the vacuum circuit breaker when no status signal is received within a preset time period.

[0061] In the present invention, if the cost of the circuit breaker phase selection opening and closing device is taken into consideration, and because the MOS tube has the characteristics of low power consumption, small size, low cost, high stability, and fast response speed, the present solution can also select an N-type MOS tube as the closing device 3. However, although the closing device 3 can be turned on and off accordingly according to the control of the phase selection control system 1, when the phase selection control system 1 fails, the N-type MOS tube cannot transmit the opening and closing instructions to the coil of the vacuum circuit breaker. Therefore, the present solution additionally sets a state collector and a redundant control system. The state collector is used to collect the state signal periodically sent by the phase selection control system, and the redundant control system is used to determine whether the phase selection control system 1 fails according to the situation of receiving the state signal. When the state signal sent by the phase selection control system 1 is not received within the preset time period, it can be determined that the phase selection control system 1 fails. At this time, in order to ensure that the vacuum circuit breaker can perform opening and closing control normally, the redundant control system needs to transmit the opening and closing instructions received by itself to the coil of the vacuum circuit breaker, so that the vacuum circuit breaker can still perform corresponding opening and closing in the existing manner, that is, according to the opening and closing instructions when the phase selection control system 1 fails, which greatly improves the reliability of the scheme.

[0062] As an optional embodiment, it also includes:

[0063] A first unidirectional conduction module D1, wherein the input end of the first unidirectional conduction module D1 is connected to the power supply, and the output end is connected to the first end of the opening device 2;

[0064] The second unidirectional conduction module D2 has an input end connected to the opening and closing instruction, and an output end connected to the first end of the closing device 3.

[0065] In the present invention, in order to ensure that the coil of the vacuum circuit breaker can accurately receive the electric energy or the opening and closing instructions transmitted by the power supply, the present scheme additionally provides a first unidirectional conduction module D1 and a second unidirectional conduction module D2, wherein the first unidirectional conduction module D1 is respectively connected to the first end of the power supply and the opening device 2, and can ensure that when the opening device 2 is turned on, the electric energy transmitted by the power supply is transmitted to the coil of the vacuum circuit breaker; similarly, the second unidirectional conduction module D2 is respectively connected to the opening and closing instructions and the first end of the closing device 3, and can ensure that when the closing device 3 is closed, the opening and closing instructions are transmitted to the coil of the vacuum circuit breaker, thereby improving the reliability of the scheme.

[0066] As an optional embodiment, the opening device 2 further includes:

[0067] Delay relay K1, the first end of the coil of the delay relay K1 is connected to the opening and closing instructions, the second end of the coil of the delay relay K1 is connected to the ground, the moving contact of the normally open contact of the delay relay K1 is connected to the power supply, and the static contact of the normally open contact of the delay relay K1 is connected to the first end of the opening device 2, which is used to close the moving contact and the static contact after the first preset time after receiving the opening instruction, and disconnect the moving contact and the static contact after the first preset time after receiving the closing instruction.

[0068] In the present invention, it is considered that if the opening device 2 includes only one N-type MOS tube, if the N-type MOS tube is turned off at this time, the device of the vacuum circuit breaker is in the closed state, but the phase selection control system 1 suddenly fails after just sending an electrical signal to control the N-type MOS tube. At this time, if the opening device 2 includes only one N-type MOS tube, the N-type MOS tube will be directly turned on after receiving the electrical signal transmitted by the phase selection control system 1, so that the coil of the vacuum circuit breaker is energized, but because the option control system has failed, it is impossible to control the N-type MOS tube to be turned off, and the coil of the high-voltage circuit breaker will receive both the electric energy transmitted by the power supply and the opening and closing instructions at the same time. If the opening and closing instructions are closing instructions, the high-voltage circuit breaker will fail to close, thereby causing the rail vehicle to fail. Therefore, this solution adds a delay relay K1 on the basis of the N-type MOS tube. The function of the delay relay K1 is to delay the preset time to turn on or off after receiving the opening and closing command. Therefore, if the phase selection control system 1 fails in time, the delay relay K1 can also prevent the power of the power supply from being transmitted to the coil of the high-voltage circuit breaker according to the opening and closing command. In addition, the use of the delay relay K1 not only enables the high-voltage circuit breaker to perform subsequent opening and closing operations normally when the phase selection control system 1 fails, but also takes into account that if the N-type MOS tube is continuously turned on and off in a short time, it will cause the N-type MOS tube to fail. Therefore, delaying the preset time before turning on or off can avoid the N-type MOS tube from being continuously turned on and off in a short time, thereby greatly improving the safety and reliability of the solution.

[0069] It should be noted that if Figure 2 As shown, Q1 is the opening device 2, K2 is the closing device 3, D2 and K2 are the phase selection closing control circuit, K2 is the phase selection closing switch, and the controller controls the output of the phase selection closing command. K2 selects the normally closed contact of the relay to ensure that when the phase selection control system 1 fails, the main breaker can open and close according to the original control method; D1, K1, and Q1 are the phase selection opening control circuit, and Q1 is the phase selection opening switch. When the opening command arrives, Q1 quickly turns on to provide energy to keep the main breaker closed during the phase selection opening stage, and the controller controls (disconnects) to achieve phase selection opening. K1 is a delay relay K1, which selects the normally open contact to ensure that when the phase selection control system 1 is abnormal, the main breaker can open within a certain time after the opening command arrives.

[0070] It should also be noted that the phase selection control system 1 of this scheme is initialized: relay K2 is disconnected and waits for the main breaker closing command; phase selection closing: after monitoring the closing command, the phase selection control system 1 calculates the delay time required before relay K2 closes and outputs the closing command according to the phase of the network voltage at the time the command arrives and the expected closing delay of the vacuum circuit breaker, and closes relay K2 after the delay, and the vacuum circuit breaker selects the phase to close; phase selection opening: after monitoring the opening command, relay K2 is disconnected, and the phase selection opening control switch Q1 is put into operation at the same time. According to the phase of the current at the time the command arrives, the delay time required before Q1 disconnects and outputs the opening and closing command is calculated, and the switch tube Q1 is disconnected after the delay, and the vacuum circuit breaker selects the phase to open. If the main breaker is not disconnected within a certain time (delayed disconnection time of delay relay K1) after the opening command arrives, the main breaker can be forcibly disconnected by delay relay K1.

[0071] It should also be noted that if Figure 3 As shown, the switch tube Q2 can replace the relay K2 in the original closing circuit, but an additional redundant closing instruction is required (if the main breaker fails to close within the specified time due to a fault in the phase selection control system 1, the redundant closing instruction will close the main breaker), that is, a status collector and a redundant control system are added. This also ensures that the main breaker closing function is not affected by the fault in the phase selection control system 1. At the same time, using the switch tube Q2 instead of the relay K2 can avoid the influence of the relay action delay on the phase selection accuracy.

[0072] It should also be noted that the present application realizes online adjustment of the phase selection and closing function delay, ensuring the accuracy of the phase selection and closing; when the phase selection control system 1 fails, the vacuum circuit breaker can be opened and closed according to the original control method, that is, when an abnormal situation occurs in the phase selection control system 1, the vacuum circuit breaker can be reliably opened.

[0073] Please refer to Figure 4 , Figure 4 A process flow chart of a circuit breaker phase selection and separation method provided by the present invention. The circuit breaker phase selection and separation method is applied to the option control system in the above-mentioned circuit breaker phase selection and separation device, and the circuit breaker phase selection and separation device also includes: an opening device 2 and a closing device 3; the first end of the closing device 3 is connected to the opening and closing command, and the second end is connected to the coil of the vacuum circuit breaker; the first end of the opening device 2 is connected to the power supply, and the third end is connected to the coil of the vacuum circuit breaker; the input end of the phase selection control system 1 is connected to the opening and closing command, and the output end is respectively connected to the control end of the closing device 3 and the control end of the opening device 2; the method includes:

[0074] S11: Obtain opening and closing instructions, which include closing instructions and opening instructions;

[0075] S12: Based on the received closing command, the closing device 3 and the opening device 2 are controlled to be opened, and based on the received opening command, the closing device 3 is controlled to be opened and the opening device 2 is controlled to be closed.

[0076] The circuit breaker phase selection and separation method provided in this embodiment corresponds to the above-mentioned device, so it has the same beneficial effects as the above-mentioned device. Therefore, for the embodiments of the circuit breaker phase selection and separation method part, please refer to the description of the embodiments of the device part, which will not be repeated here.

[0077] As an optional embodiment, controlling the closing device 3 and the opening device 2 to be opened based on the received closing instruction, and controlling the closing device 3 to be opened and the opening device 2 to be closed based on the received opening instruction, includes:

[0078] The voltage phase of the transformer in a first preset period is obtained, and the vacuum circuit breaker is connected to the power grid and the transformer respectively;

[0079] The moment when the voltage phase is a first preset voltage phase is used as the closing time, and the moment when the voltage phase is a second preset voltage phase is used as the opening time, the first preset voltage phase indicates that the grid voltage received by the transformer is equal to the grid voltage peak value, and the second preset voltage phase indicates that the grid current received by the transformer is at the current zero crossing point;

[0080] At the closing time, a first signal is sent to the closing device and a second signal is sent to the opening device to control the closing device 3 and the opening device 2 to be opened; at the opening time, a third signal is sent to the closing device and a fourth signal is sent to the opening device to control the closing device 3 to be opened and the opening device 2 to be closed.

[0081] In the present invention, considering that under ideal conditions, if the voltage of the power grid connected to the vacuum circuit breaker is at the peak value of the power grid voltage, controlling the vacuum circuit breaker to close can avoid closing surge current. Similarly, if the current of the power grid is at the zero point, controlling the vacuum circuit breaker to open can avoid zero-crossing arc extinguishing. Therefore, the option control system in this scheme needs to first obtain the voltage phase of the transformer within the first preset period, and when the voltage phase is the first preset voltage phase, it is determined that the corresponding power grid voltage is at the peak value of the power grid voltage at this time, and the corresponding moment is used as the closing time. Similarly, if the voltage phase is the second preset voltage phase, the current of the power grid is at the zero point at this time, and the corresponding moment is used as the opening time. The phase selection control system 1 sends corresponding signals to the closing device 3 and the opening device 2 according to the closing time and the opening time, for example: at the closing time, the closing device 3 and the opening device 2 are controlled to be opened; at the opening time, the closing device 3 is controlled to be opened and the opening device 2 is controlled to be closed, so that the vacuum circuit breaker can be accurately opened and closed to avoid the occurrence of closing surge current and zero-crossing arc extinguishing problems.

[0082] It should be noted that for the scenario where the main breaker is put into the unloaded transformer when the locomotive is over-phased, causing the closing inrush current, the equivalent principle is as follows Figure 5 As shown in the figure: A is the closing circuit of a single-phase transformer TR, and B is the equivalent circuit after the transformer is equivalent to a phase transformer TR, and the primary and secondary leakage inductances (Lk1, Lk2), primary and secondary resistances (R1, R2), excitation losses, equivalent resistance (Rm) and equivalent inductance (Lm) are added. Because the secondary leakage inductance Lk1 is much smaller than the excitation inductance Lm, the excitation loss equivalent resistance Rm is usually large, and the transformer secondary is open circuit, therefore, B can be simplified to circuit C. The "·" in the following formula is the calculation symbol for multiplication.

[0083] The electrical circuit equation for closing the circuit breaker is:

[0084] ; (1)

[0085] ; (2)

[0086] in, is the input current, is the transformer flux. If the inductance Unsaturated, inductive is a constant, obtained from formula 2:

[0087] ; (3)

[0088] Substituting equation 3 into equation 1 yields:

[0089] ; (4)

[0090] Voltage , is the preset voltage coefficient, with:

[0091] ; (5)

[0092] The flux linkage is a non-homogeneous first-order linear differential equation. For non-homogeneous linear differential equations, the homogeneous equation can be solved first:

[0093] ; The solution of (6).

[0094] Arranging equation 6 yields:

[0095] ; (7)

[0096] Integrating both sides of equation 7 yields:

[0097] ; (8)

[0098] You can get:

[0099] ; (9)

[0100] The homogeneous equation 5 has a general solution:

[0101] ; (10)

[0102] Substituting equation 10 into equation 5 yields:

[0103] ; (11)

[0104] After finishing, we get:

[0105] ; (12)

[0106] Bundle Expressed in complex exponential form, j is a preset parameter,

[0107] ; (13)

[0108] Substituting 13 into equation 12, we can obtain:

[0109] ; (14)

[0110] Integrating both sides of equation 14 yields:

[0111] ; (15)

[0112] At t=0, , we can find:

[0113] ; (16)

[0114] but:

[0116] ; (17)

[0117] In the formula, , the first term is the transient flux, which decays to 0 over time, and the second term is the steady-state flux, which maintains the same amplitude. is the magnetizing inductive reactance, R1 is the winding resistance, usually , Equation 17 can be simplified as:

[0118] ; (18)

[0119] t is the closing moment, and the steady-state flux amplitude is , if the voltage is 0 at the time of closing, that is =0, , ......,at this time: ; (19)

[0120] At the beginning of closing, the flux amplitude is close to , which is twice the steady-state flux, which is the so-called flux doubling effect. In order to reduce the cost of the transformer, the transformer flux is at 90% saturation point under rated voltage, so the transformer will be deeply saturated, with a large excitation current, causing a closing surge.

[0121] It can be seen from formula 19 that the positive peak of the magnetic flux will be larger than the steady-state peak, and the negative peak of the magnetic flux will be smaller than the steady-state peak, that is, the magnetic flux is saturated in the positive direction but not in the negative direction.

[0122] Figure 6 It is the excitation current waveform when the transformer flux is not saturated, the positive and negative half-waves are basically symmetrical, and the deviation is small; Figure 7 This is the waveform of the excitation current when the transformer flux is normally saturated. It can be seen that the positive and negative half-wave currents are obviously asymmetric, the positive current is greater than the negative current, and the average current in one cycle is positive.

[0123] Therefore, the saturation degree and direction of the transformer magnetic flux can be judged by the average value of the current within one cycle. The larger the absolute value of the average current, the higher the saturation degree, and vice versa.

[0124] If the voltage is 0 at the time of closing, that is .....,at this time:

[0125] The transformer flux is: ; (20)

[0126] It can be seen that at the initial stage of closing, the negative magnetic flux is close to twice the steady-state magnetic flux, the magnetic flux is negatively saturated, and a negative surge current will appear.

[0127] If the voltage is 0 at the time of closing, that is ......,at this time:

[0128] The transformer flux is: ;(twenty one)

[0129] The transient magnetic flux of the transformer is 0. After closing the switch, the magnetic flux directly enters the steady state and the magnetic flux amplitude remains unchanged. The magnetic excitation current waveform is as follows: Figure 6 As shown, no closing surge current occurs at this time.

[0130] According to the above analysis:

[0131] 1. The transformer closing surge current is caused by the fact that the sum of the transient magnetic flux and the steady-state magnetic flux of the transformer is greater than the saturation magnetic flux when closing, which causes a large excitation current and forms a closing surge;

[0132] 2. Transformer When closing the circuit breaker, the transformer flux is close to twice the rated magnetic energy, which will cause a large surge current. Therefore, closing the circuit breaker at this moment should be avoided.

[0133] 3. The surge current of the transformer is asymmetric. The surge current appears in the direction of magnetic flux saturation. The saturation degree and direction can be determined based on the sign and size of the average surge current during the same period.

[0134] 4. Transformer voltage phase ......When closing the circuit breaker, the excitation current is basically symmetrical and there is no closing inrush current. The closing time should be selected at these points.

[0135] As an optional embodiment, after controlling the closing device 3 and the opening device 2 to be disconnected, the method further includes:

[0136] Determine whether the vacuum circuit breaker is in a closed state;

[0137] If the vacuum circuit breaker is in the closed state, delaying for a second preset time to obtain the average current value of the power grid within a second preset period;

[0138] Adjust the closing timing according to the relationship between the average current and the preset current range.

[0139] In the present invention, considering that as the number of times the opening device 2 and the closing device 3 are used increases, the fatigue of the operating machinery will also affect the closing timing, and then affect the accuracy of the closing, so the tone closing timing of the vacuum circuit breaker should be dynamically adjusted according to the actual state, that is, the transformer saturation state detection is added after the vacuum circuit breaker is closed, and the next closing timing is adjusted according to the saturation degree. In addition, because the sign and magnitude of the average current in a cycle after the vacuum circuit breaker is closed represent the saturation degree of the transformer, it also provides a prompt for the adjustment direction of the next closing timing. Therefore, this scheme first judges the state of the vacuum circuit breaker. When the state of the vacuum circuit breaker is the closed state, the second preset time is delayed to obtain the current average value of the power grid in the second preset cycle, and the closing timing is adjusted according to the size relationship between the current average value and the preset current range. This scheme reflects the saturation degree of the transformer according to the current average value of the power grid to adjust the closing timing of the vacuum circuit breaker next time, so as to ensure that the closing timing is adjusted according to the actual situation, so as to avoid the occurrence of closing surge current problems.

[0140] It should be noted that, according to the above analysis, the phase selection controller collects the network voltage and primary current in real time, takes the arrival time of the opening and closing command as the reference and combines the expected closing delay of the vacuum circuit breaker, and controls the phase selection opening and closing switch (delay for a period of time) by calculation, so as to select the closing of the vacuum circuit breaker at the peak of the network voltage (avoiding the closing surge current) and the breaking of the vacuum circuit breaker at the current zero crossing point. The principle of phase selection opening is simple, and the present invention will not be described in detail. The following is the control principle of phase selection closing.

[0141] Considering that the action delay of relay K2 and the closing delay of vacuum circuit breaker have certain dispersion (affected by the power supply voltage of relay and the operating pressure of circuit breaker), in addition, as the number of times of use increases, the fatigue degree of operating machinery will also affect the delay, which will affect the expected closing delay of vacuum circuit breaker, and then affect the phase selection closing accuracy. Therefore, the expected closing delay of vacuum circuit breaker should be dynamically adjusted according to the actual state. The implementation principle is to increase the transformer saturation state detection each time and adjust the next expected closing delay according to the saturation degree:

[0142] According to the above analysis, the sign and magnitude of the average current in one cycle after closing the circuit breaker represent the saturation degree of the transformer, and also provide us with the direction for adjusting the next delay. Figure 8 The block diagram of the automatic search for calibrating the closing delay at the positive peak of the voltage is given.

[0143] After the circuit breaker is closed, delay 20mS (tentative) and read the average value of the transformer current. , to determine whether it is within the allowed range (in , ), is the rated minimum value of the average value of the transformer current, This is the rated maximum value of the average current of the transformer. If it is within this range, there is no need to adjust the delay time.

[0144] if , indicating that the magnetic flux is positively saturated, the closing point is on the left side of the positive peak, and the delay should be increased; on the contrary, if , indicating that the magnetic flux is negatively saturated and the closing point is on the right side of the positive peak value. The time delay should be reduced. The adjusted time should be saved to prepare for the next main circuit breaker closing. Figure 8 The calibration is to close the automatic time delay search at the positive peak value of the voltage. If the calibration is to close the circuit breaker at the negative peak value of the voltage, the adjustment direction should be exactly the opposite.

[0145] It should also be noted that 1. It is difficult to accurately control the closing time at the voltage peak. In fact, we can reduce the peak current by controlling the saturation of the transformer to a certain extent and avoiding closing the circuit near the voltage of 0. If the voltage can be controlled to close at an angle of 30 degrees, the maximum magnetic flux of the transformer will be 1.5 times the rated magnetic flux, and the surge current peak will be greatly reduced. Therefore, and It should be adjusted according to the test situation; 2. The delay time should be updated and stored after each closing to avoid re-searching after the next power-on; 3. Increment The smaller t is, the better the effect of suppressing the closing surge current is. That is, if the delay value adjusted each time is small, the target delay that meets the conditions will be located more accurately. If t is too small, the search speed will be too slow, so first consider 250uS. Each angle adjustment corresponds to 4.5 degrees, which is a smoother change.

[0146] As an optional embodiment, adjusting the closing timing according to the relationship between the current average value and the preset current range includes:

[0147] If the current average value is greater than the maximum current value in the preset current range, the transformer is judged to be positively saturated in the magnetic flux, and the closing timing is increased by a preset value;

[0148] If the current average value is less than the maximum current value in the preset current range, it is determined that the magnetic flux of the transformer is negatively saturated, and the closing timing is reduced by a preset value.

[0149] In the present invention, the specific process of adjusting the closing timing according to the size relationship between the current average value and the preset current range is: if the current average value is greater than the current maximum value of the preset current range, it is determined that the magnetic flux of the transformer is positively saturated, and at this time, the closing timing needs to be increased by the preset value; conversely, if the current average value is less than the current maximum value of the preset current range, it is determined that the magnetic flux of the transformer is negatively saturated, and at this time, the closing timing needs to be reduced by the preset value, so that the next closing control can be performed according to the adjusted closing timing to avoid the occurrence of closing inrush current problems.

[0150] It should be noted that, in this specification, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the statement "comprises a ..." does not exclude the presence of other identical elements in the process, method, article or device including the element.

[0151] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A circuit breaker phase selection and switching device, characterized in that: include: Phase selection control system, opening device, closing device; The first end of the closing device is connected to the opening and closing instructions, and the second end is connected to the coil of the vacuum circuit breaker, and is used to close when the phase selection control system fails, and transmit the opening and closing instructions to the coil of the vacuum circuit breaker, and the opening and closing instructions include: closing instructions and opening instructions; The first end of the opening device is connected to the power supply, and the second end is connected to the coil of the vacuum circuit breaker; The input end of the phase selection control system is connected to the opening and closing instructions, and the output end is respectively connected to the control end of the closing device and the control end of the opening device, and is used to control the closing device and the opening device to open based on the received closing instruction, and to control the closing device to open and the opening device to close based on the received opening instruction.

2. The circuit breaker phase selection and switching device according to claim 1, characterized in that: The closing device is a relay, a first end of the coil of the relay is connected to the output end of the phase selection control system, a second end of the coil of the relay is connected to the ground, a moving contact of the relay is connected to the opening and closing instructions, a normally closed contact of the relay is connected to the coil of the vacuum circuit breaker, and a normally open contact of the relay is suspended, and is used to control the moving contact of the relay to be connected to the normally open contact of the relay after the coil of the relay receives a first electrical signal output when the phase selection control system receives the closing instruction, and to control the moving contact of the relay to be connected to the normally open contact of the relay after the coil of the relay receives a second electrical signal output when the phase selection control system receives the opening instruction, and when a fault occurs in the phase selection control system, the moving contact of the relay is connected to the normally closed contact of the relay.

3. The circuit breaker phase selection and switching device according to claim 1, characterized in that: The opening device is a first N-type MOS transistor, the gate of the first N-type MOS transistor is connected to the output end of the phase selection control system, the drain of the first N-type MOS transistor is connected to the power supply, and the source of the first N-type MOS transistor is connected to the coil of the vacuum circuit breaker, and is used to be turned on after receiving a first electrical signal output when the phase selection control system receives the opening instruction, and turned off after receiving a second electrical signal output when the phase selection control system receives the closing instruction.

4. The circuit breaker phase selection and switching device according to claim 1, characterized in that: The closing device is a second N-type MOS transistor, the gate of the second N-type MOS transistor is connected to the output end of the phase selection control system, the drain of the second N-type MOS transistor is connected to the opening and closing instruction, and the source of the second N-type MOS transistor is connected to the coil of the vacuum circuit breaker, and is used to shut down after the coil of the relay receives a first electrical signal output after the phase selection control system receives the closing instruction, and shut down after the coil of the relay receives a second electrical signal output after the phase selection control system receives the opening instruction; The circuit breaker phase selection and switching device further comprises: A state collector, which is connected to the phase selection control system and is used to obtain a state signal periodically sent by the phase selection control system; A redundant control system, wherein a first input end of the redundant control system is connected to the opening and closing instructions, a second input end is connected to the status collector, and an output end is connected to the coil of the vacuum circuit breaker, and is used to send the opening and closing instructions to the vacuum circuit breaker when the status signal is not received within a preset time period.

5. The circuit breaker phase selection and switching device according to claim 1, characterized in that: Also includes: a first unidirectional conduction module, wherein an input end of the first unidirectional conduction module is connected to the power supply, and an output end of the first unidirectional conduction module is connected to a first end of the opening device; A second one-way conducting module, wherein the input end of the second one-way conducting module is connected to the opening and closing instruction, and the output end is connected to the first end of the closing device.

6. The circuit breaker phase selection and switching device according to any one of claims 1 to 5, characterized in that: The opening device further comprises: A time delay relay, wherein the first end of the coil of the time delay relay is connected to the opening and closing instruction, the second end of the coil of the time delay relay is connected to the ground, the moving contact of the normally open contact of the time delay relay is connected to the power supply, and the static contact of the normally open contact of the time delay relay is connected to the first end of the opening device, and is used to close the moving contact and the static contact after a first preset time after receiving the opening instruction, and to disconnect the moving contact and the static contact after the first preset time after receiving the closing instruction.

7. A circuit breaker phase selection and separation method, characterized in that: An option control system applied to a circuit breaker phase selection and opening and closing device according to any one of items 1 to 6, wherein the circuit breaker phase selection and opening and closing device further comprises: an opening device and a closing device; the first end of the closing device is connected to an opening and closing instruction, and the second end is connected to the coil of the vacuum circuit breaker; the first end of the opening device is connected to a power supply, and the third end is connected to the coil of the vacuum circuit breaker; the input end of the phase selection control system is connected to the opening and closing instruction, and the output end is respectively connected to the control end of the closing device and the control end of the opening device; the method comprises: Obtaining a switch-on / off instruction, wherein the switch-on / off instruction includes a switch-on instruction and a switch-off instruction; The closing device and the opening device are controlled to be opened based on the received closing instruction, and the closing device is controlled to be opened and the opening device is controlled to be closed based on the received opening instruction.

8. The circuit breaker phase selection and switching method according to claim 7, characterized in that: The controlling the closing device and the opening device to be opened based on the received closing instruction, and controlling the closing device to be opened and the opening device to be closed based on the received opening instruction, comprises: Acquiring a voltage phase of the transformer in a first preset period, wherein the vacuum circuit breaker is connected to a power grid and the transformer respectively; The moment when the voltage phase is a first preset voltage phase is used as the closing time, and the moment when the voltage phase is a second preset voltage phase is used as the opening time, wherein the first preset voltage phase indicates that the grid voltage received by the transformer is equal to the grid voltage peak value, and the second preset voltage phase indicates that the grid current received by the transformer is at the current zero crossing point; At the closing time, a first signal is sent to the closing device and a second signal is sent to the opening device to control the closing device and the opening device to be opened; at the opening time, a third signal is sent to the closing device and a fourth signal is sent to the opening device to control the closing device to be opened and the opening device to be closed.

9. The circuit breaker phase selection and switching method according to claim 8, characterized in that: After controlling the closing device and the opening device to be disconnected, the method further comprises: Determining whether the vacuum circuit breaker is in a closed state; If the vacuum circuit breaker is in a closed state, delaying for a second preset time to obtain an average current value of the power grid within a second preset period; The closing timing is adjusted according to the magnitude relationship between the current average value and the preset current range.

10. The circuit breaker phase selection and switching method according to claim 9, characterized in that: The adjusting the closing timing according to the magnitude relationship between the current average value and the preset current range includes: If the current average value is greater than the maximum current value in the preset current range, it is determined that the magnetic flux of the transformer is forward saturated, and the closing timing is increased by a preset value; If the current average value is less than the maximum current value in the preset current range, it is determined that the magnetic flux of the transformer is negatively saturated, and the closing timing is reduced by the preset value.

Images