Intelligent monitoring and switching device and method for voltage of traction substation

Abstract

The invention discloses an intelligent voltage monitoring and switching device and method for a traction substation, and relates to the technical field of railway traction power supply. Each section of bus of the traction substation is provided with a main voltage transformer and a standby voltage transformer, and each voltage transformer is provided with a voltage transformer fault monitoring module; each voltage transformer fault monitoring module comprises a voltage discrimination circuit, a voltage normal discrimination circuit, a non-voltage discrimination circuit, a low voltage value discrimination circuit, a high voltage difference discrimination circuit, a voltage transformer abnormity discrimination circuit and a voltage transformer normal discrimination circuit. And the voltage automatic switching device judges whether to switch the currently running voltage transformer according to the voltage transformer abnormal signal or the voltage transformer normal signal output by each voltage transformer fault monitoring module. Whether the voltage transformer is abnormal or not is comprehensively judged according to the normal mark of the voltage transformer, so that the fault of the used voltage transformer is determined, and the standby voltage transformer is automatically put into use.

Description

Technical Field

[0001] This invention relates to the field of railway traction power supply technology, specifically to a smart voltage monitoring and switching device and method for traction substations. Background Technology

[0002] In railway traction power supply systems, devices such as traction network feeder protection and fault location systems all need to collect bus voltage data. Bus voltage is the basis for protection actions and fault location calculations during faults. In actual operation, most 27.5kV voltage transformers are equipped with high-voltage side fuses, and these fuses are mostly of a ceramic tube, quartz sand, and fuse wire structure. After the fuse blows, the break is very small, and a high induced voltage still exists. At this time, because the voltage switching device can still collect the induced voltage, it cannot automatically switch to the backup voltage transformer, affecting the safe operation of the entire traction power supply system. In the event of a fuse failure, after the protection trips, the voltage data acquisition becomes abnormal, and the fault location error increases, affecting fault judgment and emergency response. Summary of the Invention

[0003] The purpose of this invention is to provide a voltage intelligent monitoring and switching device and method for traction substations. Based on the normal status indicator of the voltage transformer, the device comprehensively judges whether the voltage transformer is abnormal, thereby determining whether the voltage transformer in use is faulty or the high and low voltage fuses have blown, and automatically switching to a standby voltage transformer.

[0004] To achieve the above objectives, this application provides the following solution: On one hand, this invention provides a voltage intelligent monitoring and switching device for traction substations, including an automatic voltage switching device. Each bus section of the traction substation is equipped with a main voltage transformer and a backup voltage transformer. For each voltage transformer, a voltage transformer fault monitoring module is provided. Each voltage transformer fault monitoring module includes a voltage presence detection circuit, a voltage normality detection circuit, a voltage absence detection circuit, a low voltage value detection circuit, a high voltage difference detection circuit, a voltage transformer abnormality detection circuit, and a voltage transformer normality detection circuit, wherein: The voltage detection circuit triggers a voltage-activated signal; The voltage normality detection circuit triggers the voltage transformer normality signal based on the voltage operation signal. The no-voltage detection circuit triggers a no-voltage action signal based on the normal signal from the voltage transformer. The low voltage detection circuit triggers a low voltage signal based on the normal voltage transformer signal. The voltage difference high detection circuit triggers a voltage difference high signal based on the normal signal from the voltage transformer. The voltage transformer fault detection circuit triggers voltage transformer fault signals based on no-voltage action signals, low voltage signals, and high voltage difference signals. The voltage transformer normal operation detection circuit triggers the voltage transformer normal operation signal based on the voltage on operation signal, voltage off operation signal, low voltage signal, and high voltage difference signal. The automatic voltage switching device determines whether to switch the currently operating voltage transformer based on the abnormal or normal voltage transformer signals output by the fault monitoring module of each voltage transformer.

[0005] In some specific implementations, the voltage discrimination circuit includes a voltage comparator 1 that compares the fundamental component of the input bus voltage with the voltage setting value, an AND logic device 1 that performs AND logic processing on the output of the voltage comparator 1 and the voltage soft plate input signal, and an output voltage action signal after a set time limit on the output of the AND logic device 1.

[0006] In some specific implementations, when the fundamental component of the input bus voltage is greater than or equal to the voltage setting value, a voltage operation signal is output. When the voltage normality discrimination circuit receives the voltage operation signal, the voltage transformer normality flag is set and a voltage transformer normality signal is output. When the fundamental component of the input bus voltage is lower than the no-voltage setting value, the voltage normality judgment circuit instantaneously resets the voltage transformer normality mark.

[0007] In some specific implementations, the no-voltage discrimination circuit includes a voltage comparator two that compares the fundamental component of the input voltage transformer voltage with the no-voltage setting value, an AND logic device two that performs AND logic processing on the output of the voltage comparator two, the voltage transformer normal signal, and the no-voltage non-operation signal, the AND logic device two outputs a no-voltage start signal, and after the no-voltage start signal passes through a set time limit, outputs a no-voltage operation signal.

[0008] In some specific implementations, the low voltage detection circuit includes a current comparator 1 that compares the absolute value of the difference between the T-line bus current and the F-line bus current of the input main voltage transformer with the maximum value of the bus load current, and a current comparator 2 that compares the absolute value of the difference between the T-line bus current and the F-line bus current of the input standby voltage transformer with the maximum value of the bus load current, and an OR logic device 1 that performs OR logic processing on the output results of current comparator 1 and current comparator 2. It also includes a low voltage soft switch that triggers the low voltage soft switch signal, and a voltage comparator three that compares the input bus voltage value with the minimum bus voltage value. And the AND logic device three performs AND logic processing on the input signal of the low voltage value soft pressure plate of the voltage transformer, the normal signal of the voltage transformer, or the output result of logic device one and the output result of voltage comparator three, and outputs a low voltage signal after the output result of the AND logic device three has been processed for a set time limit.

[0009] In some specific implementations, the high voltage difference detection circuit includes a high voltage difference soft plate that triggers the input signal of the high voltage difference soft plate. Voltage comparator four compares the absolute value of the voltage difference obtained by calculating the difference between the input T-line bus voltage of the main voltage transformer and the T-line bus voltage of the standby voltage transformer with the set inherent error value. Voltage comparator five compares the ratio obtained by dividing the input standby voltage transformer's T-line bus voltage by the main voltage transformer's T-line bus voltage with the set voltage comparison coefficient. And AND logic device four, which performs AND logic processing on the input signal of the soft pressure plate with high voltage difference between the voltage transformers, the normal signal of the voltage transformer, the output result of voltage comparator four, and the output result of voltage comparator five, outputs a high voltage difference signal after the output result of AND logic device four has been processed for a set time limit.

[0010] In some specific implementations, the voltage transformer fault detection circuit includes an OR logic device two that performs an OR logic operation on the no-voltage action signal, the low voltage signal, and the high voltage difference signal, and outputs a voltage transformer fault signal from the OR logic device two.

[0011] In some specific implementations, the voltage transformer normal detection circuit includes a non-logic device that performs non-logic processing on the low voltage signal. Non-logic device two performs non-logic processing on the no-pressure action signal, non-logic device three performs non-logic processing on the high voltage difference signal, AND logic device five performs AND logic processing on the outputs of non-logic device one, non-logic device two, non-logic device three, and the pressure action signal, and AND logic device five outputs the normal signal of the voltage transformer.

[0012] In some specific implementations, the automatic voltage switching device includes a T-line voltage switching hard plate that triggers the signal to activate the T-line voltage switching hard plate, and a T-line bus voltage switching soft plate that triggers the signal to activate the T-line bus voltage switching soft plate. If the primary voltage transformer is currently in operation, when it receives the following signals: automatic switching hard plate activation signal for T-line voltage transformer, automatic switching soft plate activation signal for T-line bus voltage transformer, signal indicating that the TF-line bus is not in the isolation position, or an abnormal signal from the primary voltage transformer and a normal signal from the standby voltage transformer, it will output a voltage switching signal and automatically switch to the standby voltage transformer.

[0013] Secondly, this application provides a method for intelligent voltage monitoring and switching in traction substations, specifically including the following steps: S1. Obtain the fundamental bus voltage components of the currently operating voltage transformer and the standby voltage transformer respectively, and monitor the operating status of the two voltage transformers respectively. The monitoring method is as follows: S11. When the fundamental component of the bus voltage is greater than the voltage setting value, output a voltage-activated signal and set the voltage normality flag of the voltage transformer. When the fundamental component of the bus voltage is lower than the voltage-free setting value, instantaneously reset the voltage normality flag of the currently operating voltage transformer. S12. Based on the voltage normal marking of the voltage transformer, determine whether the voltage transformer is operating without voltage, whether the voltage value is too low, and whether the voltage difference is too high. S13. When the voltage transformer simultaneously meets the conditions of no-voltage operation, low voltage value, and high voltage difference, the output voltage transformer is abnormal. When the voltage transformer simultaneously meets the conditions of no-voltage operation, no low voltage value, no high voltage difference, and voltage operation, the output voltage transformer is normal. S2. If the operating status of the currently operating voltage transformer is abnormal and the operating status of the standby voltage transformer is normal, the automatic voltage switching device will switch the currently operating voltage transformer to the standby voltage transformer.

[0014] The beneficial effects of this invention are as follows: By analyzing voltage curves and related fault waveforms of the 27.5kV bus voltage at traction substations, section substations, and AT substations during fuse failures, and combining this with voltage switching rules, the voltage change characteristics during fuse failures are extracted and compared. Based on these voltage characteristics under fuse failure conditions, a method is designed to compare the voltage waveforms or difference trends of the primary and backup PTs, thereby locating the voltage transformer that experienced the fuse failure. This invention does not require high-voltage side power outages or direct detection on the high-voltage side. The intelligent monitoring device does not affect existing equipment or circuits during operation. Upon determining that the voltage transformer in use has failed or that both high-voltage and low-voltage fuses have blown, the backup voltage transformer is automatically switched on. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the logic circuit of the intelligent voltage monitoring and switching device for traction substations provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the voltage transformer anomaly detection principle provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the pressure discrimination principle provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of the pressureless discrimination principle provided in an embodiment of the present invention; Figure 5 This is a schematic diagram illustrating the principle of low voltage detection provided in an embodiment of the present invention. Figure 6 This is a schematic diagram illustrating the principle of high voltage difference detection provided in an embodiment of the present invention. Figure 7This is the voltage transformer anomaly detection principle provided in the embodiments of the present invention; Figure 8 This is the normal operation detection principle of the voltage transformer provided in the embodiments of the present invention; Figure 9 This is a secondary voltage switching principle diagram provided in an embodiment of the present invention; Figure 10 The automatic voltage switching logic provided in this embodiment of the invention; Figure 11 This invention provides a method for determining if the voltage angle difference is too high, as described in the embodiments of the present invention. Detailed Implementation

[0016] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of the invention.

[0018] At the same time, it should be understood that, for ease of description, the dimensions of the various parts shown in the accompanying drawings are not drawn according to actual scale.

[0019] Furthermore, for clarity and brevity, descriptions of well-known structures, functions, and configurations may have been omitted. Those skilled in the art will recognize that various changes and modifications can be made to the examples described herein without departing from the spirit and scope of this disclosure.

[0020] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0021] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0022] Example 1 like Figure 1As shown, this embodiment provides a voltage intelligent monitoring and switching device for traction substations, including an automatic voltage switching device. Each bus section of the traction substation is equipped with a main voltage transformer and a backup voltage transformer. Each voltage transformer is equipped with a voltage transformer fault monitoring module. Each voltage transformer fault monitoring module includes a voltage presence detection circuit, a voltage normality detection circuit, a voltage absence detection circuit, a low voltage value detection circuit, a high voltage difference detection circuit, a voltage transformer abnormality detection circuit, and a voltage transformer normality detection circuit, wherein: The voltage detection circuit triggers a voltage-activated signal; Specifically, the voltage discrimination circuit includes a voltage comparator 1 that compares the fundamental component of the input bus voltage with the voltage setting value, an AND logic device 1 that performs AND logic processing on the output of the voltage comparator 1 and the voltage soft plate input signal, and an output voltage action signal after a set time limit on the output of the AND logic device 1.

[0023] The voltage normality detection circuit triggers the voltage transformer normality signal based on the voltage operation signal. Specifically, when the fundamental component of the input bus voltage is greater than or equal to the voltage setting value, a voltage operation signal is output. When the voltage normality discrimination circuit receives the voltage operation signal, the voltage transformer normality flag is set and a voltage transformer normality signal is output. When the fundamental component of the input bus voltage is lower than the no-voltage setting value, the voltage normality judgment circuit instantaneously resets the voltage transformer normality mark.

[0024] The no-voltage detection circuit triggers a no-voltage action signal based on the normal signal from the voltage transformer. Specifically, the no-voltage detection circuit includes a voltage comparator two that compares the fundamental component of the input voltage transformer voltage with the no-voltage setting value; an AND logic device two that performs AND logic processing on the output of voltage comparator two, the voltage transformer previously normal signal, and the no-voltage non-operation signal; the AND logic device two outputs a no-voltage start signal; and after a set time limit, it outputs a no-voltage operation signal. The low voltage detection circuit triggers a low voltage signal based on the voltage transformer previously normal signal. Specifically, the low voltage detection circuit includes a current comparator 1 that compares the absolute value of the difference between the T-line bus current and the F-line bus current of the input main voltage transformer with the maximum value of the bus load current; a current comparator 2 that compares the absolute value of the difference between the T-line bus current and the F-line bus current of the input standby voltage transformer with the maximum value of the bus load current; an OR logic device 1 that performs OR logic processing on the output results of current comparator 1 and current comparator 2; and a low voltage soft plate that triggers the low voltage soft plate input signal, and a voltage comparator 3 that compares the input bus voltage value with the minimum bus voltage value. And the AND logic device three performs AND logic processing on the input signal of the low voltage value soft pressure plate of the voltage transformer, the normal signal of the voltage transformer, or the output result of logic device one and the output result of voltage comparator three, and outputs a low voltage signal after the output result of the AND logic device three has been processed for a set time limit.

[0025] The voltage difference high detection circuit triggers a voltage difference high signal based on the normal signal from the voltage transformer. Specifically, the high voltage difference detection circuit includes a high voltage difference soft plate that triggers the input signal of the high voltage difference soft plate. Voltage comparator four compares the absolute value of the voltage difference obtained by calculating the difference between the input T-line bus voltage of the main voltage transformer and the T-line bus voltage of the standby voltage transformer with the set inherent error value. Voltage comparator five compares the ratio obtained by dividing the input standby voltage transformer's T-line bus voltage by the main voltage transformer's T-line bus voltage with the set voltage comparison coefficient. And AND logic device four, which performs AND logic processing on the input signal of the soft pressure plate with high voltage difference between the voltage transformers, the normal signal of the voltage transformer, the output result of voltage comparator four, and the output result of voltage comparator five, outputs a high voltage difference signal after the output result of AND logic device four has been processed for a set time limit.

[0026] The voltage transformer fault detection circuit triggers voltage transformer fault signals based on no-voltage action signals, low voltage signals, and high voltage difference signals. Specifically, the voltage transformer abnormality detection circuit includes an OR logic device two that performs an OR logic operation on the no-voltage action signal, the low voltage signal, and the high voltage difference signal, and outputs a voltage transformer abnormality signal from the OR logic device two.

[0027] The voltage transformer normal operation detection circuit triggers the voltage transformer normal operation signal based on the voltage on operation signal, voltage off operation signal, low voltage signal, and high voltage difference signal. Specifically, the voltage transformer normal detection circuit includes a non-logic device one that performs non-logic processing on a low voltage signal, a non-logic device two that performs non-logic processing on a no-voltage operation signal, a non-logic device three that performs non-logic processing on a high voltage difference signal, an AND logic device five that performs AND processing on the outputs of non-logic device one, non-logic device two, non-logic device three, and the voltage operation signal, and the output of AND logic device five is the voltage transformer normal signal.

[0028] The automatic voltage switching device determines whether to switch the currently operating voltage transformer based on the abnormal or normal voltage transformer signals output by the fault monitoring module of each voltage transformer.

[0029] The automatic voltage switching device includes a T-line voltage switching hard plate that triggers the signal to activate the T-line voltage switching hard plate, and a T-line bus voltage switching soft plate that triggers the signal to activate the T-line bus voltage switching soft plate. If the primary voltage transformer is currently in operation, when it receives the following signals: automatic switching hard plate activation signal for T-line voltage transformer, automatic switching soft plate activation signal for T-line bus voltage transformer, signal indicating that the TF-line bus is not in the isolation position, or an abnormal signal from the primary voltage transformer and a normal signal from the standby voltage transformer, it will output a voltage switching signal and automatically switch to the standby voltage transformer.

[0030] Understandably, railway traction substations (stations) typically install two 27.5kV voltage transformers per section of the 27.5kV busbar, forming a redundancy mode of one main and one backup. This is to ensure that if one voltage transformer fails, the busbar voltage can be switched to the other voltage transformer. The analog voltage of the 27.5kV busbar voltage transformer is crucial data for the measurement and control of the traction substation. If it is interrupted or abnormal, it will cause malfunctions in the traction substation feeder system impedance protection, the high-voltage and low-voltage side overcurrent protection of the main transformer system, and the fault location device, interrupting the power supply to the contact network equipment and leading to serious deviations in metering and measurement data.

[0031] An anomaly occurred during the switching of the main and backup voltage transformers on the busbar of the current railway traction substation, causing the main low-voltage start-up overcurrent protection to malfunction, seriously endangering the safe operation of traction power supply.

[0032] For example, in actual operation, most 27.5kV voltage transformers are equipped with high-voltage fuses, which are mostly ceramic tubes, quartz sand, and fuse wire structures. After the fuse blows, the break is very small, and a high induced voltage still exists, preventing the voltage switching device from automatically switching to the standby transformer. Therefore, in the event of a fuse failure, protection tripping will occur, voltage data acquisition will be abnormal, and ranging errors will increase, affecting fault diagnosis and emergency response.

[0033] The substation typically uses an AT (Automatic Transformer) power supply method. A total of four voltage transformers are installed on the 27.5kV busbar. 1YH and 2YH form one group (mutual backup), 3YH and 5YH form another group (mutual backup), and 4YH and 6YH form yet another group (mutual backup). Each voltage transformer includes a T-line voltage transformer and an F-line voltage transformer, for a total of eight transformers. In the event of a voltage transformer failure, the busbar voltage can be switched to another working voltage transformer, improving power supply reliability. Voltage transformers 3YH, 4YH, 5YH, and 6YH have anomaly monitoring and active fault detection functions.

[0034] The following uses the primary voltage transformer UT1-1 as an example to illustrate how the device in this application monitors abnormalities in the voltage transformer. Figure 2The diagram shown illustrates the overall discrimination principle; the monitoring method for other voltage transformers is the same. The following sections describe each module in detail: 1.1 Pressure detection The principle of pressure discrimination is as follows Figure 3 As shown. UT1-1 is the fundamental component of the bus voltage, Uset is the voltage setting value, and Tset is the time setting value. When the fundamental component of the bus voltage is greater than or equal to the voltage setting value, the output UT1-1 is voltage-sensitive; the device has 8 voltage channels, each with its own voltage discrimination element, but they all share a set of voltage setting values.

[0035] 1.2, Voltage was previously normal. Taking UT1-1 as an example, when it is determined that UT1-1 is under voltage, the UT1-1 voltage was once normal. When the UT1-1 voltage value is lower than the no-voltage setting value, the UT1-1 voltage was once normal.

[0036] 1.3 No-pressure discrimination The principle of pressureless discrimination is as follows Figure 4 As shown. UT1-1 represents the fundamental voltage component of the voltage transformer, Uset is the no-voltage setting value, and Tset is the no-voltage time setting value. When the fundamental voltage component of the voltage transformer was previously under voltage but did not operate under no-voltage conditions, and the fundamental voltage component of the voltage transformer is less than or equal to the no-voltage setting value, the output starts under no-voltage conditions, and operates under no-voltage conditions after the no-voltage time limit. The device has 8 voltage channels, each with its own independent no-voltage detection element, but shares a common set of no-voltage settings.

[0037] 1.4. Voltage value is too low The principle of judging low voltage value is as follows: Figure 5 As shown, Um.min is the minimum bus voltage and Im.min is the maximum bus load current. When the UT1-1 voltage is normal and UT1-1 < the minimum bus voltage, and the difference between the TF line bus currents of the main voltage transformer or the standby voltage transformer is less than the maximum bus load current, the output UT1-1 voltage value is low. 1.5. Voltage difference is too high Taking UT1-1 as an example, the explanation is similar for other voltage converters. The principle for detecting excessive voltage difference is as follows: Figure 6As shown, K is the voltage comparison coefficient, which can be adjusted, with a default value of 1.01. When the voltage of UT1-1 is normal, and the bus voltage difference between the primary and backup voltage transformers is greater than the inherent error value of the measured values ​​of the two voltage transformers, and the bus voltage ratio between the primary and backup voltage transformers is greater than the voltage comparison coefficient, the output voltage difference of UT1-1 is too high. To better compare the voltages of UT1-1 and UT1-2, when UT1-2 is operating normally near its rated voltage, and the voltage of U1-1 is within 95% to 105% of that of UT1-2, the fine-tuning coefficient of UT1-1 can be calibrated using UT1-2 as a reference to compensate for system errors and maintain consistent measured voltages between the two voltage transformers during normal operation.

[0038] 1.6 Voltage Transformer Abnormal Judgment Logic Taking UT1-1 as an example, the fault detection logic for voltage transformers is explained; the fault detection logic for the other seven voltage transformers is similar. The principle of voltage transformer fault detection is as follows: Figure 7 As shown, when UT1-1 operates with no voltage, low voltage, or high voltage difference, the main voltage transformer is judged to be faulty. If the voltage transformer is judged to be faulty, a fault report is generated, and the sampled data of the two cycles before the fault and the eight cycles after the fault are sent up as the fault waveform.

[0039] 1.7 Voltage Transformer Normal Operation Judgment Logic Taking UT1-1 as an example, the normal operation judgment logic of the voltage transformer is explained. The abnormal operation judgment logic of the other seven voltage transformers is similar. The normal operation judgment principle of the voltage transformer is as follows: Figure 8 As shown, when UT1-1 has no voltage and UT1-1 voltage is too low, or UT1-1 voltage difference is too high and neither of these conditions applies, but UT1-1 has voltage, the main voltage transformer UT1-1 is functioning normally.

[0040] 2. Voltage switching device The system is equipped with three redundant voltage switching operations: automatic voltage switching, remote voltage switching, and manual voltage switching. Each group of primary and backup voltage transformers offers three switching options: manual, automatic, and remote. Remote switching includes active switching from the dispatch terminal, switching by on-duty personnel on the back-end system, and response switching. Response switching is a human-machine interface function; when an abnormality is detected in a running voltage transformer, the integrated automation back-end system displays an alarm message, and on-duty personnel determine whether to switch the voltage based on the situation. The automatic voltage switching function of the voltage transformer monitoring and switching device can switch from the primary voltage transformer to the backup voltage transformer, and vice versa. Before switching, the device must confirm that the voltage of the other (group of) voltage transformers is normal.

[0041] The secondary principle diagram of voltage switching is as follows Figure 9 As shown, the automatic switching of bus voltages T1, T2, F1, and F2 is performed independently. Taking bus T1 as an example, terminals (D1, D2) and (D3, D4) are two sets of contacts of the same relay, with (D1, D2) being normally closed contacts and (D3, D4) being normally open contacts. In principle, the primary voltage is connected to terminals (D1, D2), and the standby voltage is connected to terminals (D3, D4). The voltage connection of other bus lines follows the same principle. Assuming the initial state is UT1-1 primary and UT1-2 standby, i.e., (D1, D2) closed and (D3, D4) open, the following explains these three methods in turn: 2.1 Automatic voltage switching Assuming the initial state is UT1-1 as the primary switch and UT1-2 as the backup switch, i.e., (D1, D2) are closed and (D3, D4) are open, the automatic voltage switching logic is as follows: Figure 10 As shown in the diagram, the "T1 voltage automatic switching hard switch" is the hardware input of the device. The "T1 bus voltage automatic switching soft switch" is the user-defined soft switch. The voltage switching signal output drives the signal plug-in relay, opening the terminals (D1, D2) and closing the terminals (D3, D4).

[0042] The device automatically identifies the switching action result. If the switching is successful, it reports an event of "automatic voltage switching successful". If the switching fails, it reports "automatic voltage switching circuit abnormal" and simultaneously reports a self-test report of "voltage switching relay malfunction", illuminates the alarm light, and blocks the automatic voltage switching action of this bus. The device can only be restored to function after the fault is eliminated.

[0043] After a successful automatic throw / switch action, there is a 20-second automatic reset time before the next action can begin, or you can reset the action by pressing the reset button on the panel within 20 seconds.

[0044] 2.2 Remote Voltage Switching Taking the T1 bus as an example, the voltage remote control switching function is enabled when the "T1 voltage automatic switching hard switch" is engaged and the "T1 bus voltage automatic switching soft switch" is disengaged. The remote control should be configured as a single-position direct control mode.

[0045] 2.3 Manual voltage switching When remote control is not possible due to communication failure, the device supports manual switching. Taking the T1 bus as an example, the manual switching function is enabled when the "T1 automatic switching hard pressure plate" is deactivated. When the trigger power is turned on to B017, terminals (D1, D2) are closed and terminals (D3, D4) are open; when the trigger power is turned on to B017, terminals (D1, D2) are open and terminals (D3, D4) are closed.

[0046] The device also provides an alarm for excessive voltage transformer angle difference on the busbar. When the voltage angle difference between two voltage transformers on the same busbar exceeds a threshold Φ, an alarm signal is issued, and an event report is generated and saved. The UT1-1 busbar is used as an example; the criteria for judging the voltage angle difference on other busbar sections are similar. Figure 11 As shown, the logic for judging a high voltage angle difference is as follows: when the difference in voltage angles between two voltage transformers on the same bus is greater than the threshold Φ and both are greater than the setting value USY, the voltage angle difference of the voltage transformers is judged to be too high. To better compare the voltage angles of UT1-1 and UT1-2, when UT1-1 and UT1-2 are operating normally near their rated voltages, the voltage angle of UT1-1 can be used as a reference to fine-tune the angle of UT1-1 to compensate for system errors and keep the voltage angle difference between the two voltage transformers close to zero during normal operation.

[0047] The device also provides an active fault detection function for voltage transformers, which can detect faults in each of the eight voltage transformer branches by connecting the detection loop. The fault detection process for each loop is similar. The following describes the fault detection process using the loop containing UT1-1 as an example. After receiving the remote control detection command for the voltage transformer in the loop containing UT1-1, the device records the voltage amplitude of UT1-1, sends a command to connect the detection of the voltage transformer in the loop containing UT1-1, and after a delay t (adjustable, default value is 30 milliseconds), records the voltage amplitude of UT1-1 at this time. Then, it retracts the command to connect the voltage transformer detection loop, calculates the voltage difference before and after the loop is connected, and if the difference is greater than the set value, it is judged as a voltage transformer fault, generates a fault report, and sends the sampled data of the first two cycles and the last eight cycles of the remote control as the fault waveform.

[0048] Example 2 This embodiment provides a method for intelligent voltage monitoring and switching in traction substations, applied in the device described in Embodiment 1, including: S1. Obtain the fundamental bus voltage components of the currently operating voltage transformer and the standby voltage transformer respectively, and monitor the operating status of the two voltage transformers respectively. The monitoring method is as follows: S11. When the fundamental component of the bus voltage is greater than the voltage setting value, output a voltage-activated signal and set the voltage normality flag of the voltage transformer. When the fundamental component of the bus voltage is lower than the voltage-free setting value, instantaneously reset the voltage normality flag of the currently operating voltage transformer. S12. Based on the voltage normal marking of the voltage transformer, determine whether the voltage transformer is operating without voltage, whether the voltage value is too low, and whether the voltage difference is too high. S13. When the voltage transformer simultaneously meets the conditions of no-voltage operation, low voltage value, and high voltage difference, the output voltage transformer is abnormal. When the voltage transformer simultaneously meets the conditions of no-voltage operation, no low voltage value, no high voltage difference, and voltage operation, the output voltage transformer is normal. S2. If the operating status of the currently operating voltage transformer is abnormal and the operating status of the standby voltage transformer is normal, the automatic voltage switching device will switch the currently operating voltage transformer to the standby voltage transformer.

[0049] Understandably, to ensure the safe and stable operation of the traction power supply system, the 27.5kV intelligent voltage monitoring device proposed in this application does not require a power outage on the high-voltage side, nor does it require direct detection on the high-voltage side. The operation of the intelligent monitoring device will not affect existing equipment or circuits. When it is determined that the high-voltage fuse has blown, the result can be displayed intuitively, allowing for judgment. When the high-voltage fuse has not blown, the real-time measured voltage data can be displayed intuitively, and an alarm sound can be issued to indicate that the voltage is within the normal operating range. Upon determining that the voltage transformer in use is faulty or that the high- or low-voltage fuse has blown, the backup voltage transformer is automatically switched on, integrating the 27.5kV intelligent voltage monitoring device into the integrated automation system. The switching information of the voltage transformer is transmitted to the dispatch terminal via the remote control system, meeting the requirement of unmanned operation in the traction substation. The 27.5kV intelligent voltage monitoring and switching device for railway traction substations proposed in this application can be based on the PAC (Programmable Controller) hardware and software platform. The software development adopts the "VLD" visual logic development tool, and the device has offline logic simulation capabilities, achieving "transparent" accident analysis.

[0050] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Based on the technical essence of the present invention, any simple modifications, equivalent substitutions, and improvements made to the above embodiments within the spirit and principles of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A traction substation voltage intelligent monitoring switching device, characterized by, The voltage automatic switching device, main voltage transformers and standby voltage transformers are arranged on each bus of the traction substation, and each voltage transformer is provided with a voltage transformer fault monitoring module. The voltage discrimination circuit triggers a voltage action signal; The voltage once normal discrimination circuit triggers a voltage transformer once normal signal according to the voltage action signal; The no voltage discrimination circuit triggers a no voltage action signal according to the voltage transformer once normal signal; The voltage value low discrimination circuit triggers a voltage low signal according to the voltage transformer once normal signal; The voltage difference high discrimination circuit triggers a voltage difference high signal according to the voltage transformer once normal signal; The voltage transformer abnormal discrimination circuit triggers a voltage transformer abnormal signal according to the no voltage action signal, the voltage low signal and the voltage difference high signal; The voltage transformer normal discrimination circuit triggers a voltage transformer normal signal according to the voltage action signal, the no voltage action signal, the voltage low signal and the voltage difference high signal; The voltage automatic switching device judges whether to switch the current running voltage transformer according to the voltage transformer abnormal signal or the voltage transformer normal signal output by each voltage transformer fault monitoring module.

2. A voltage intelligent monitoring and switching device for a traction substation as claimed in claim 1, characterized in that, The voltage discrimination circuit includes a voltage comparator one comparing the input bus voltage fundamental component with a voltage setting value, and a logical and device one performing logical and processing on the output result of the voltage comparator one and a voltage soft pressure plate input signal, and outputting a voltage action signal after a set time limit.

3. A voltage monitoring and switching device for a traction substation according to claim 2, characterized in that When the input bus voltage fundamental component is greater than or equal to the voltage setting value, the voltage action signal is output, and the voltage once normal discrimination circuit receives the voltage action signal and sets a voltage transformer once normal flag and outputs a voltage transformer once normal signal; When the input bus voltage fundamental component is lower than the voltage setting value, the voltage once normal discrimination circuit resets the voltage transformer once normal flag.

4. A voltage monitoring and switching device for a traction substation according to claim 1, characterized in that The no voltage discrimination circuit includes a voltage comparator two comparing the input voltage transformer voltage fundamental component with a no voltage setting value, a logical and device two performing logical and processing on the output result of the voltage comparator two, the voltage transformer once normal signal and a no voltage action signal, and outputting a no voltage action signal after a set time limit.

5. A voltage monitoring and switching device for a traction substation according to claim 1, characterized in that The voltage value low discrimination circuit includes a current comparator one comparing the absolute value of the difference between the T bus current and the F bus current of the main voltage transformer with a bus load current maximum value, and a current comparator two comparing the absolute value of the difference between the T bus current and the F bus current of the standby voltage transformer with the bus load current maximum value, and an or logical device one performing logical or processing on the output result of the current comparator one and the output result of the current comparator two; The voltage difference high soft panel input signal, the voltage transformer once normal signal, the voltage comparator four output result, the voltage comparator five output result are subjected to AND logic processing by an AND logic device four, and a voltage difference high signal is output after a set time limit of the AND logic device four output result. The voltage difference high soft panel input signal, the voltage transformer once normal signal, the voltage comparator four output result, the voltage comparator five output result are subjected to AND logic processing by an AND logic device four, and a voltage difference high signal is output after a set time limit of the AND logic device four output result.

6. A voltage monitoring and switching device for a traction substation as claimed in claim 1, characterized in that The voltage transformer abnormality discrimination circuit comprises an OR logic device two for performing OR logic operation on the no-voltage action signal, the voltage low signal and the voltage difference high signal. The voltage transformer normality discrimination circuit comprises a NOT logic device one for performing NOT logic operation on the voltage low signal, a NOT logic device two for performing NOT logic operation on the no-voltage action signal, a NOT logic device three for performing NOT logic operation on the voltage difference high signal, and an AND logic device five for performing AND logic operation on the NOT logic device one output, the NOT logic device two output, the NOT logic device three output and the voltage action signal, and outputting a voltage transformer normal signal. The voltage automatic switching device comprises a T-line voltage transformer automatic switching hard panel for triggering a T-line voltage transformer automatic switching hard panel input signal, and a T-line bus voltage automatic switching soft panel for triggering a T-line bus voltage automatic switching soft panel input signal.

7. A voltage monitoring and switching device for a traction substation as claimed in claim 1, characterized in that If the currently running voltage transformer is the main voltage transformer, when the T-line voltage transformer automatic switching hard panel input signal, the T-line bus voltage automatic switching soft panel input signal, the TF-line bus isolation not in the split signal, the main voltage transformer abnormal signal and the standby voltage transformer normal signal are received, a voltage switching signal is output, and the standby voltage transformer is automatically switched.

8. A voltage monitoring and switching device for a traction substation according to claim 1, characterized in that The method comprises the following steps: S1, bus voltage fundamental components of a currently running voltage transformer and a standby voltage transformer are acquired respectively, and running states of the two voltage transformers are monitored respectively, and the monitoring method is as follows:

9. A voltage monitoring and switching device for a traction substation according to claim 4, characterized in that S11, when the bus voltage fundamental component is greater than a voltage action setting value, a no-voltage action signal is output and a voltage transformer once normal flag of the voltage transformer is set, and when the bus voltage fundamental component is lower than a no-voltage setting value, the voltage transformer once normal flag of the currently running voltage transformer is instantaneously reset. ​ 10. A method of intelligent monitoring and switching of traction substation voltage, characterized by, ​ ​ ​ S12, respectively judging whether the voltage transformer is no-voltage action, the voltage value is low and the voltage difference is high according to the voltage normal flag of the voltage transformer; S13, when the voltage transformer simultaneously satisfies no-voltage action, low voltage value and high voltage difference, outputting that the voltage transformer is abnormal, and when the voltage transformer simultaneously satisfies not no-voltage action, not low voltage value, not high voltage difference and voltage action, outputting that the voltage transformer is normal; S2, if the running state of the currently running voltage transformer is voltage transformer abnormal and the running state of the standby voltage transformer is voltage transformer normal, the voltage automatic switching device switches the currently running voltage transformer to the standby voltage transformer.

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