Method for controlling two sections of buses of three paths of power supplies by five switches

Abstract

The invention relates to the technical field of power transformation and distribution, in particular to a method for controlling two sections of buses of three power supplies through five switches. The method comprises the following steps that three paths of input power supplies are connected with two sections of buses through five switches, the first path of input power supply is connected to the I section of bus through a switch 1, the second path of input power supply is connected to the II section of bus through a switch 2, the third path of input power supply is connected to the I section of bus and the II section of bus through a switch 3 and a switch 4 respectively, and the I section of bus and the II section of bus are connected through an interconnection switch 5; electrical parameters of three paths of input power supplies and two sections of buses are collected through a power supply sampling device, and the power supply sampling device transmits the collected electrical parameters to a monitoring module through a CAN communication bus for sampling; and the monitoring module analyzes and processes the electrical parameters, generates a control instruction according to a preset control logic, and transmits the control instruction to the operating mechanism through the CAN communication bus for control, so that the problems of insufficient power supply reliability and poor economical efficiency in the prior art can be solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power transformation and distribution, and particularly relates to a method for controlling three power supplies and two bus sections by five switches. BACKGROUND

[0002] In the technical field of power transformation and distribution, the reliability of station power supply of 110KV and above substations is crucial to the stable operation of substations. In the prior art, the traditional station power supply usually adopts two-way input and realizes automatic switching through two ATSs, but there is a risk of system power failure when both two-way power supplies fail. In order to improve the reliability, important substations begin to adopt three-way power supply. At present, the three-way power supply scheme usually follows the structure of two ATSs plus several switches, wherein one ATS contains two switches, the actual number of switches of the system is relatively large, equivalent to 10 switches, which leads to an increase in the electrical loop link, a large use of cross-cabinet copper bars, and a significant increase in copper consumption and switch cost. At the same time, although the ATS in these schemes can work automatically, the additional switches need to be operated manually. When one or two power supplies fail and the power supply mode needs to be switched, the manual operation response is slow, which easily prolongs the power failure time. Moreover, the power supply switching logic is fixed and cannot be flexibly adjusted according to the preset priority, so it is difficult to guarantee the continuity of power supply in the switch maintenance scene.

[0003] Based on the above problems, there is an urgent need for a three-way power supply and two-section bus control scheme that can reduce the number of switches, reduce costs, and realize automatic and flexible switching, in order to solve the problems of insufficient power supply reliability and poor economy in the prior art. SUMMARY

[0004] The purpose of the present application is to solve the shortcomings in the prior art, and a method for controlling three power supplies and two bus sections by five switches is proposed, which comprises the following steps: Three input power supplies are connected to two bus sections through five switches, wherein the first input power supply is connected to the I section bus through switch 1, the second input power supply is connected to the II section bus through switch 2, and the third input power supply is connected to the I section bus and the II section bus through switch 3 and switch 4 respectively, and the I section bus and the II section bus are connected through the tie-in switch 5; The electrical parameters of the three input power supplies and the two bus sections are collected by the power sampling device, and the collected electrical parameters are transmitted to the monitoring module through the CAN communication bus for sampling; After analyzing and processing the electrical parameters, the monitoring module generates control instructions according to the preset control logic, and transmits the control instructions to the operating mechanism through the CAN communication bus for control, and the operating mechanism controls the closing and opening of the five switches; The monitoring module also communicates with a remote control terminal through a remote communication line, receives remote control operation instructions and executes corresponding switch control, wherein the preset control logic includes three power supply modes, and in each power supply mode, the closing and opening states of the switches are automatically switched according to the fault states of the three input power sources and the switch maintenance requirements.

[0005] Preferably, the electrical parameters collected by the power supply sampling device include voltage, current, phase, frequency, active power, reactive power and power factor, wherein the electrical parameters of the first input power source are collected by the power supply sampling device arranged at the input end of switch 1, the electrical parameters of the second input power source are collected by the power supply sampling device arranged at the input end of switch 2, the electrical parameters of the third input power source are collected by the power supply sampling device arranged at the input ends of switch 3 and switch 4, and the electrical parameters of the first bus and the second bus are collected by the power supply sampling devices arranged on the first bus and the second bus, respectively.

[0006] Further preferably, the three power supply modes include: in the first power supply mode, the first input power source supplies power to the first bus and the second input power source supplies power to the second bus in the normal state, the second input power source supplies power to the first bus through switch 2 and tie switch 5 when the first input power source fails, the first input power source supplies power to the second bus through switch 1 and tie switch 5 when the second input power source fails, and the third input power source serves as a backup; in the second power supply mode, the first input power source supplies power to the first bus and the second input power source supplies power to the second bus in the normal state, the third input power source supplies power to the first bus through switch 3 when the first input power source fails, the third input power source supplies power to the second bus through switch 4 when the second input power source fails, and the first input power source and the second input power source serve as backups for each other when the third input power source fails; in the third power supply mode, the third input power source supplies power to the two buses through the corresponding switches and tie switches when the first input power source and the second input power source fail or the switches need to be maintained.

[0007] Further preferably, in the first power supply mode, when the first input power source and the second input power source are both normal, switch 1 and switch 2 are closed, and switch 3, switch 4 and tie switch 5 are opened; when the first input power source fails and the second input power source is normal, switch 2 and tie switch 5 are closed, and switch 1, switch 3 and switch 4 are opened; when the first input power source is normal and the second input power source fails, switch 1 and tie switch 5 are closed, and switch 2, switch 3 and switch 4 are opened; when the first input power source and the second input power source both fail and the third input power source is normal, switch 3 and switch 4 are closed, and switch 1, switch 2 and tie switch 5 are opened.

[0008] Further preferably, in the second power supply mode, when the first input power supply fails, the second input power supply is normal and the third input power supply is normal, the switch 2 and the switch 3 are closed, and the switch 1, the switch 4 and the contact switch 5 are disconnected; when the first input power supply fails, the second input power supply is normal and the third input power supply fails, the switch 2 and the contact switch 5 are closed, and the switch 1, the switch 3 and the switch 4 are disconnected; when the first input power supply is normal, the second input power supply fails and the third input power supply is normal, the switch 1 and the switch 4 are closed, and the switch 2, the switch 3 and the contact switch 5 are disconnected; when the first input power supply is normal, the second input power supply fails and the third input power supply fails, the switch 1 and the contact switch 5 are closed, and the switch 2, the switch 3 and the switch 4 are disconnected.

[0009] Further preferably, the operating mechanism includes five independent operating units corresponding to the switch 1 to the switch 5 respectively, each of which is connected with the monitoring module through the control CAN communication bus, receives the control instruction sent by the monitoring module and drives the corresponding switch to perform the closing or disconnecting action, and the working power supply of the operating mechanism is a 220V direct current uninterrupted power supply, which is jointly provided by the station direct current power supply and the storage battery.

[0010] Further preferably, when generating the control instruction, the monitoring module needs to calculate the switch residual life based on the switch cumulative switching times, the working temperature and the power grid harmonic distortion rate, and the calculation formula is: ; wherein, the switch residual mechanical life is RML, the switch rated mechanical life is RML0, the switch actual cumulative switching times are ACT, the switch rated switching times are RST, the temperature influence coefficient is TIC, the switch current working temperature is T, the reference temperature is T0, the harmonic influence coefficient is HIC, the power grid total harmonic distortion rate is THD.

[0011] Further preferably, the monitoring module also needs to calculate the real-time contact resistance based on the copper bar initial contact resistance, the working temperature and the passing current, and the calculation formula is: ; wherein, the copper bar contact resistance at t time is R(t), the copper bar initial contact resistance is R0, the copper bar thermal expansion coefficient is α, the copper bar current working temperature is T, the reference temperature is T0, the Joule heat influence coefficient is JIC. is the real-time current of the copper bar, is the copper bar contact resistance at time t, is the calculation duration.

[0012] Further preferably, the monitoring module calculates a switching decision correction coefficient based on the remaining life of the switch, the real-time contact resistance of the copper bar, and the total harmonic distortion rate of the power grid, which is used to adjust the switching trigger threshold value, and the calculation formula is: ; wherein, is the switching decision correction coefficient, is the remaining mechanical life of the switch, is the rated mechanical life of the switch, is the copper bar contact resistance at time t, is the initial contact resistance of the copper bar, is the total harmonic distortion rate of the power grid.

[0013] Further preferably, the monitoring module applies the switching decision correction coefficient to the control command generation process, when an abnormality in the electrical parameters of the power supply or bus is detected, the actual switching trigger threshold value is the product of the reference threshold value and , when , the monitoring module automatically preferentially selects the third input power supply as the power supply to reduce the number of switch switching, when , the monitoring module adjusts the copper bar passing current by controlling the closing state of the tie switch 5 to reduce the growth rate of the real-time contact resistance of the copper bar.

[0014] Technical effects: The present application connects three power supplies and two bus sections through five switches, replaces the traditional ATS and multiple switches, reduces the number of switches and copper bars, reduces the cost and the electrical circuit link, realizes automatic control with the help of the power supply sampling device, the monitoring module and the CAN communication, and does not need manual operation. Three power supply modes are designed to realize flexible switching. The problems of insufficient power supply reliability caused by too many switches, high cost, dependence on manual operation, and inflexible switching in the prior art are solved. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 is the method principle diagram of the present application for controlling three power supplies and two bus sections through five switches; Figure 2 is the first switch state diagram of the first power supply mode of the present application; Figure 3 is the second switch state diagram of the first power supply mode of the present application; Figure 4 is the third switch state diagram of the first power supply mode of the present application; Figure 5 The fourth switching state chart for the first power supply mode of the present application; Figure 6 The first switching state chart for the second power supply mode of the present application; Figure 7 The second switching state chart for the second power supply mode of the present application; Figure 8 The third switching state chart for the second power supply mode of the present application; Figure 9 The fourth switching state chart for the second power supply mode of the present application; Figure 10 The fifth switching state chart for the second power supply mode of the present application; Figure 11 The sixth switching state chart for the second power supply mode of the present application; Figure 12 The first switching state chart for the third power supply mode of the present application; Figure 13 The second switching state chart for the third power supply mode of the present application; Figure 14 The third switching state chart for the third power supply mode of the present application.

[0016] In the figure: 1, 1QF switch; 2, 2QF switch; 3, 3QF switch; 4, 4QF switch; 5, 5QF tie switch; 6, monitoring module; 7, I section bus; 8, II section bus; 9, CAN communication bus for control; 10, CAN communication bus for sampling; 11, shunt output switch; 12, 1st power supply sampling device; 13, 2nd power supply sampling device; 14, 3rd power supply sampling device; 15, I section bus power supply sampling device; 16, II section bus power supply sampling device; 17, switch 1 operating mechanism; 18, switch 3 operating mechanism; 19, switch 4 operating mechanism; 20, switch 2 operating mechanism; 21, switch 5 operating mechanism; 22, remote control communication line. DETAILED DESCRIPTION

[0017] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and do not limit the present application.

[0018] The traditional technical solution has the following technical problems: In the control of three power sources and two bus sections, the existing solution usually uses two ATSs plus multiple switches. The ATS contains two switches and the switches need to be manually operated, resulting in a large number of system switches, equivalent to 10 switches, and many electrical circuit links. This not only increases copper consumption and costs, but also has the problem of untimely switching. At the same time, the switching logic is fixed in the event of a power failure and cannot be flexibly adjusted according to priority. There is a lack of automatic control mechanism, and reliance on manual operation can easily prolong the power outage time, resulting in insufficient power supply reliability in scenarios such as important substations.

[0019] Based on this, this embodiment provides a method for controlling three power sources and two bus sections using five switches, comprising the following steps: connecting the three input power sources to the two bus sections via five switches, wherein the first input power source is connected to bus section I via switch 1, the second input power source is connected to bus section II via switch 2, and the third input power source is connected to bus sections I and II via switches 3 and 4, respectively. Bus sections I and II are connected via a tie switch 5; collecting electrical parameters of the three input power sources and the two bus sections using a power sampling device, and transmitting the collected electrical parameters to a monitoring module via a sampling CAN communication bus; the monitoring module analyzes and processes the electrical parameters, generates control instructions according to a preset control logic, and transmits the control instructions to an operating mechanism via a control CAN communication bus, which controls the closing and opening of the five switches; the monitoring module also communicates with a remote control terminal via a remote control communication line, receives remote control operation instructions, and executes corresponding switch control. The preset control logic includes three power supply modes, and in each power supply mode, the switch automatically switches between the closed and open states based on the fault status of the three input power sources and the switch maintenance requirements.

[0020] This solution reduces the number of switches through a specific connection structure of five switches, replacing the traditional ATS and lowering costs and circuit links. CAN communication between the power sampling device and the monitoring module enables real-time parameter acquisition and automatic analysis, combined with preset control logic to achieve automatic switch switching without manual operation. The design of three power supply modes allows flexible adjustment of power switching based on priority, resolving the problem of fixed switching logic and reliance on manual operation in existing solutions. From the perspective of the electrical system, the CAN communication bus for sampling ensures the real-time and reliable transmission of parameters, the CAN communication bus for control enables the precise issuance of control commands, and communication between the monitoring module and the remote control terminal expands control flexibility. The overall combination of hardware connections and software logic achieves high reliability and low cost of power supply.

[0021] The prior art has the following technical problems: in the existing 3-way power supply and 2-section bus control, the sampling range of the power supply sampling device is not clear, some schemes only collect basic parameters such as voltage and current, and lack monitoring of key parameters such as phase, frequency and power factor, which leads to the inability to comprehensively judge the running state of the power supply and the bus, and easy misjudgment or omission of faults; at the same time, the installation position of the sampling device is not reasonable, and it is difficult to accurately obtain the real parameters of the input end of each power supply and the bus, affecting the judgment accuracy of the monitoring module on the fault state.

[0022] Therefore, the electrical parameters collected by the power supply sampling device include voltage, current, phase, frequency, active power, reactive power and power factor, wherein the electrical parameters of the first input power supply are collected by the power supply sampling device arranged at the input end of switch 1, the electrical parameters of the second input power supply are collected by the power supply sampling device arranged at the input end of switch 2, the electrical parameters of the third input power supply are collected by the power supply sampling device arranged at the input end of switch 3 and switch 4, and the electrical parameters of section I bus and section II bus are collected by the power supply sampling devices arranged on section I bus and section II bus respectively.

[0023] This scheme covers the core indicators of the running state of the power supply and the bus by clearly defining the types of sampling parameters, and the phase and frequency parameters can avoid the parallel connection risk of the power supply, and the active power, reactive power and power factor can reflect the running efficiency of the load, solving the one-sided problem of state judgment caused by incomplete parameter collection in the existing scheme; at the same time, the installation position of the sampling device accurately corresponds to the input end of each power supply and the bus, ensuring that the collected parameters can truly reflect the electrical state of the corresponding node, and providing accurate data for fault judgment of the monitoring module.

[0024] From the perspective of electricity, complete parameter collection provides comprehensive basis for subsequent control logic, such as the collection of frequency parameters can avoid switching impact caused by frequency difference of different power supplies, phase parameters provide reference for bus parallel connection control, and targeted design of sampling position reduces the influence of line loss on parameters, improving sampling accuracy.

[0025] The prior art has the following technical problems: in the existing 3-way power supply mode, the priority logic of power supply switching is not clear, when a certain power supply fails, it cannot be quickly switched to the standby power supply according to the preset priority, and switching chaos is easy to occur; at the same time, there is a lack of detailed power supply strategy for different fault scenarios, and in different scenarios such as 1-way and 2-way power supply failure or switch maintenance, the switching logic is fixed and cannot adapt to actual needs, resulting in affected power supply continuity.

[0026] Based on this, the three power supply modes include: the first power supply mode is that in the normal state, the first input power supplies power to the I section bus and the second input power supplies power to the II section bus, when the first input power fails, the second input power supplies power to the I section bus through switch 2 and tie switch 5, when the second input power fails, the first input power supplies power to the II section bus through switch 1 and tie switch 5, and the third input power is used as a backup; the second power supply mode is that in the normal state, the first input power supplies power to the I section bus and the second input power supplies power to the II section bus, when the first input power fails, the third input power supplies power to the I section bus through switch 3, when the second input power fails, the third input power supplies power to the II section bus through switch 4, and when the third input power fails, the first input power and the second input power are used as backups for each other; and the third power supply mode is that when the first input power and the second input power fail or the switch needs to be maintained, the third input power supplies power to the two section buses through the corresponding switch and tie switch according to the switch maintenance requirement.

[0027] The scheme subdivides the three power supply modes, designs clear switching logic for different fault scenarios, and solves the problem of ambiguous switching priority in the prior art scheme; the power supply switching path in each mode is clear, and in combination with the closing and opening states of the switch, the target power supply can be quickly switched when a fault occurs, and the power-off time is reduced.

[0028] From the perspective of control logic, the design of the power supply mode realizes the flexibility of the switching strategy, and the appropriate mode can be selected according to the actual requirement, for example, the second mode is selected in the scene where the reliability of the three power supplies is high, and the third mode is selected in the scene where the switch needs to be frequently maintained, so that the adaptation ability of the system is improved through the subdivision of the logic level.

[0029] The prior art scheme has the following technical problems: in the actual application of the first power supply mode, the prior art scheme does not clearly define the switch action logic under different fault states, when one or two power supplies fail, the closing and opening states of the switch lack standardization, and misoperation is likely to occur, which causes power supply in parallel or bus power-off; meanwhile, the correspondence between the switch state and the power supply fault is not clear, the monitoring module is difficult to accurately execute the switching instruction, and the continuity of power supply is affected.

[0030] Based on this, in the first power supply mode, when the first input power supply and the second input power supply are normal, switch 1 and switch 2 are closed, and switch 3, switch 4 and contact switch 5 are disconnected; when the first input power supply is faulty and the second input power supply is normal, switch 2 and contact switch 5 are closed, and switch 1, switch 3 and switch 4 are disconnected; when the first input power supply is normal and the second input power supply is faulty, switch 1 and contact switch 5 are closed, and switch 2, switch 3 and switch 4 are disconnected; when the first input power supply and the second input power supply are both faulty and the third input power supply is normal, switch 3 and switch 4 are closed, and switch 1, switch 2 and contact switch 5 are disconnected.

[0031] The scheme establishes clear action logic by clearly defining the switch state corresponding to different fault states in the first power supply mode, solving the problem of non-standard switch operation in the existing scheme; the switch combination under each fault state avoids parallel connection of the three power supplies, which can cause short circuit risk due to inconsistent phase and frequency of the three power supplies, ensuring power supply safety. From the perspective of electrical safety, the precise design of the switch state prevents power supply conflicts, such as only switch 1 and 2 being closed in the normal state to ensure that the first input power supply and the second input power supply supply power respectively without parallel connection; when a fault occurs, the closure of contact switch 5 enables power supply across the bus, while the switch corresponding to the faulty power supply is disconnected to avoid the influence of the faulty power supply on the bus, thereby ensuring the reliability of power supply through standard hardware action.

[0032] The traditional technical scheme has the following technical problems: in the second power supply mode, the existing scheme lacks clear specification for switch control in different scenarios such as all three power supplies being normal and partial faults, and when one of the three power supplies is faulty and the third input power supply is normal, the switch state is chaotic, which can easily lead to interruption of power supply to the target bus; at the same time, the switching logic after the third input power supply fails is not clear, which cannot ensure effective execution of the first input power supply and the second input power supply as backups for each other, affecting power supply continuity.

[0033] Based on this, in the second power supply mode, when the first input power supply is faulty, the second input power supply is normal and the third input power supply is normal, switch 2 and switch 3 are closed, and switch 1, switch 4 and contact switch 5 are disconnected; when the first input power supply is faulty, the second input power supply is normal and the third input power supply is faulty, switch 2 and contact switch 5 are closed, and switch 1, switch 3 and switch 4 are disconnected; when the first input power supply is normal, the second input power supply is faulty and the third input power supply is normal, switch 1 and switch 4 are closed, and switch 2, switch 3 and contact switch 5 are disconnected; when the first input power supply is normal, the second input power supply is faulty and the third input power supply is faulty, switch 1 and contact switch 5 are closed, and switch 2, switch 3 and switch 4 are disconnected.

[0034] The scheme establishes a clear switching path with the third input power supply as the priority standby by specifying the switch state of different fault scenarios in the second power supply mode, solves the problem of chaotic switch control in the existing scheme, and reduces the dependence on the first input power supply and the second input power supply when the third input power supply is normal, and automatically switches to the first input power supply and the second input power supply as standby when the third input power supply fails, ensuring uninterrupted power supply. From the perspective of power utilization efficiency, the logic fully utilizes the standby role of the third input power supply, realizes efficient switching of the power supply through precise action of the switch, avoids unnecessary switch operation, prolongs the service life of the switch, and improves the stability of the system while ensuring continuous power supply.

[0035] The traditional technical scheme has the following technical problems: the existing switch operating mechanism mostly adopts a centralized control mode, multiple switches share a control unit, when the control unit fails, all switches cannot be operated, and the operating mechanism relies on an alternating current power supply for power supply, once the alternating current power supply fails, the operating mechanism will lose power and cannot execute switching instructions, which seriously affects the emergency response capability of the power supply system; at the same time, the communication between the operating mechanism and the monitoring module lacks a clear signal transmission path, which is prone to command delay or loss, resulting in switch action lag.

[0036] Therefore, the operating mechanism includes five independent operating units corresponding to the control switches 1 to 5, each operating unit is connected with the monitoring module through a control CAN communication bus, receives the control instructions sent by the monitoring module and drives the corresponding switch to execute closing or opening action, and the working power supply of the operating mechanism is a 220V direct current uninterruptible power supply provided by a station direct current power supply and a storage battery.

[0037] The scheme realizes separate control of the switches through the five independent operating units, avoids the single point failure risk of centralized control, and only affects the corresponding switch when a certain operating unit fails, without affecting the normal operation of other switches, solving the problem of insufficient reliability of traditional centralized control; the control CAN communication bus has the characteristics of strong anti-interference ability and stable transmission rate, ensuring the real-time and accuracy of command transmission between the monitoring module and the operating mechanism, and reducing command delay; the 220V direct current uninterruptible power supply is jointly powered by the station direct current power supply and the storage battery, even if all the alternating current power supplies fail, the operating mechanism can still work normally, ensuring that the switch switching is not affected by the power supply. From the perspective of electrical system design, the setting of independent operating units conforms to the redundancy design principle, improves the fault tolerance of the system, the application of CAN communication bus adapts to the strong electromagnetic interference scene of industrial environment, and the direct current uninterruptible power supply provides stable power support for the operating mechanism, the combination of the three significantly improves the reliability of the switch operation, and provides hardware support for the continuous operation of the power supply system.

[0038] The conventional technical solution has the following technical problems: the existing switch life evaluation only depends on the cumulative switching times, does not consider the acceleration effect of temperature rise on mechanical component aging, and does not take into account the erosion effect of power grid harmonics on switch contacts, resulting in large life prediction deviation, and the switch may suddenly fail within the expected life, causing power interruption; at the same time, there is no real-time monitoring of the remaining life of the switch, and it is not possible to develop a maintenance plan in advance, and only passive maintenance after switch failure, prolonging the power outage time.

[0039] Therefore, when generating the control instruction, the monitoring module needs to calculate the switch remaining life based on the cumulative switching times of the switch, the working temperature and the power grid harmonic distortion rate, and the calculation formula is: ; Among them, is the switch remaining mechanical life, is the switch rated mechanical life, is the actual cumulative switching times of the switch, is the rated switching times of the switch, is the temperature influence coefficient, is the current working temperature of the switch, is the reference temperature, is the harmonic influence coefficient, is the total harmonic distortion rate of the power grid.

[0040] The remaining number of times that the switch can normally perform switching actions represents the core index for evaluating the health status of the switch.

[0041] The rated mechanical life is the mechanical life of the switch calibrated at the factory, which is determined by the manufacturer according to the mechanical structure of the switch, such as the contact material and spring strength, and is the reference value for life evaluation. The actual cumulative switching times of the switch from being put into use to the present time directly reflect the degree of mechanical wear and tear - each switching will cause the contact of the contact and the expansion of the spring, and the more the number of times, the more serious the wear and tear, so The term is used to quantify the proportion of life consumption caused by mechanical wear and tear.

[0042] The temperature influence coefficient is valued , which is used to convert temperature changes into life consumption factors. is the current working temperature of the switch, is the reference temperature, represents the degree of temperature deviation from the reference value: temperature rise will accelerate the aging of the switch internal lubricating grease and the oxidation of metal components, and the higher the temperature, the more significant the impact, and the square term amplifies the nonlinear impact of high temperature, so this term is used to quantify the additional consumption of temperature on life.

[0043] Harmonic influence coefficient, taking 0.05, Total harmonic distortion of power grid, reflecting the content of high-order harmonics in power grid. Harmonics will cause additional high-frequency current on the switch contact, leading to contact heating, accelerated oxidation, and the higher the harmonic distortion rate, the stronger the erosion effect. The cubic term strengthens the cumulative effect of high harmonics, so Used to quantify the consumption of life by harmonics.

[0044] Exponential function The role is to integrate each life consumption factor into a decay coefficient - the larger the value in the parentheses, the smaller the decay coefficient, The shorter, in line with the actual law of "multi-factor superposition and accelerated life decay". Through multi-parameter coupling, the formula realizes dynamic and accurate evaluation of switch life, providing a quantitative basis for early maintenance.

[0045] This scheme introduces two key factors, temperature and harmonics, to build a life calculation model that is more in line with the actual operating scenario, solving the one-sidedness of the traditional evaluation of life only according to the number of switching - the increase in temperature will cause the performance of the switch internal lubricating grease to decline and the mechanical wear to intensify, while the high-frequency current generated by harmonics will accelerate the oxidation of the contact, both of which will shorten the life of the switch. The design of the square term and the cubic term in the formula respectively reflects the cumulative effect of temperature and the nonlinear effect of harmonics; the monitoring module can grasp the switch state in real time based on the calculation results, and give an early warning when the remaining life is low, facilitating the planned maintenance of the operation and maintenance personnel. From the perspective of electrical and mechanical combination, this model realizes the cross-field correlation of electrical parameters and mechanical life, converts the monitorable electrical quantities such as power grid harmonics and operating temperature into quantitative indicators of switch life, and upgrades life evaluation from experience-based judgment to data-driven accurate prediction, providing a scientific basis for the reliable operation of the switch.

[0046] The traditional technical scheme has the following technical problems: the existing copper bar contact resistance is monitored by periodic manual measurement, which cannot reflect the dynamic change of the contact resistance in real time, and does not consider the change of contact pressure caused by thermal expansion of the copper bar, as well as the increase of resistance caused by Joule heat when current passes through, when the contact resistance increases to a certain extent, it will cause the copper bar to heat up, and even cause a fire; at the same time, the change of contact resistance lacks correlation analysis with the operating state of the power supply system, and cannot take intervention measures in advance.

[0047] Therefore, the monitoring module also needs to calculate the real-time contact resistance based on the initial contact resistance of the copper bar, the operating temperature and the passing current, and the calculation formula is: ; Where, R(t) is the contact resistance of the copper bar at time t, Initial contact resistance of copper bar, Thermal expansion coefficient of copper bar, Current working temperature of copper bar, Reference temperature, Joule heat influence coefficient, Real-time current passing through copper bar, Copper bar contact resistance at time t, Calculation duration.

[0048] In the formula, The contact resistance of the copper bar at the current time directly affects the electrical conductivity and heat generation of the copper bar. The contact resistance of the copper bar after initial installation, determined by the installation pressure and the flatness of the contact surface, is the reference value for resistance calculation.

[0049] Thermal expansion coefficient of copper bar, which is a inherent physical property of copper material. Current working temperature of copper bar, Reference temperature, Used to quantify the influence of temperature on contact resistance: when the temperature rises, the copper bar expands due to heat, which reduces the contact surface pressure and increases the contact resistance; conversely, when the temperature decreases, the contact resistance decreases. Therefore, this item directly reflects the resistance change caused by thermal expansion.

[0050] Joule heat influence coefficient, used to convert the cumulative amount of Joule heat into a resistance change factor.

[0051] The integral of Joule heat from the initial time to the current time: Real-time current passing through copper bar, Contact resistance at a certain time, Instantaneous heat power, integrated to get the cumulative heat. Heat accumulation will cause the temperature of the copper bar to rise, further exacerbating thermal expansion, and causing the oxidation film on the contact surface to thicken, increasing the contact resistance; the 0.6 power term is used to balance the non-linear relationship between heat and resistance change - when the heat increases to a certain extent, the resistance growth rate will slow down as the thickness of the oxidation film tends to stabilize.

[0052] In the overall formula, Multiply the correction term in the parentheses to get the real-time contact resistance: the first term "1" in the parentheses is the reference, the second term is the resistance increment proportion caused by thermal expansion, and the third term is the resistance increment proportion caused by Joule heat. The three are superimposed to accurately reflect the dynamic changes of the contact resistance with temperature and current, providing data support for preventing the copper bar from overheating.

[0053] ​By introducing the thermal expansion coefficient and Joule heat integral, this solution enables real-time dynamic calculation of contact resistance, resolving the lag inherent in traditional manual measurement. As the copper busbar's temperature rises, thermal expansion reduces contact pressure, increasing contact resistance. The Joule heat generated by current further increases the temperature, creating a positive feedback loop of increased resistance, intensified heating, and further resistance increase. The integral term in the formula accurately captures this cumulative effect. The monitoring module uses real-time calculations to track contact resistance trends, providing a basis for subsequent switching decisions. By coupling electricity and thermodynamics, this model correlates the copper busbar's physical properties and electrical parameters with resistance changes, making contact resistance, previously difficult to monitor directly, a calculable, quantitative indicator. This provides data support for preventing copper busbar overheating and ensuring power supply safety.

[0054] Traditional technical solutions have the following technical problems: the existing switch switching trigger threshold is a fixed value, which does not take into account the influence of actual operating conditions such as the remaining life of the switch, copper busbar contact resistance and grid harmonics. When the remaining life of the switch is short, frequent switching will accelerate its failure, and harmonic interference may cause normal voltage to be misjudged as fault voltage, causing unnecessary switching; at the same time, the setting of the switching threshold lacks flexibility and cannot adapt to the needs of different operating scenarios.

[0055] Based on this, the monitoring module calculates the switching decision correction coefficient based on the remaining life of the switch, the real-time contact resistance of the copper busbar, and the harmonic distortion rate of the power grid to adjust the switch switching trigger threshold. The calculation formula is: ; in, is the switching decision correction coefficient, is the remaining mechanical life of the switch), is the rated mechanical life of the switch, is the copper busbar contact resistance at time t, is the initial contact resistance of the copper busbar, is the total harmonic distortion rate of the power grid.

[0056] It is the switching decision correction coefficient, which directly determines the adjustment range of the actual switching trigger threshold and is the core parameter for balancing switching accuracy and equipment protection.

[0057] molecular is the remaining life of the switch: when the value is close to 1, the switch life is sufficient, the numerator is large, A high value allows switching according to the normal threshold; when the value is small, the switch life is insufficient, the numerator is reduced, As the value decreases, the switching threshold becomes stricter, reducing unnecessary switching to protect the switch.

[0058] Denominator For the contact resistance state of the copper bar: The ratio of the current contact resistance to the initial resistance, the larger the value, the larger the contact resistance, the larger the denominator, The lower the value.

[0059] Because when the contact resistance is large, frequent switching will cause current fluctuations, further exacerbating resistance growth, so by reducing The value reduces switching, avoiding vicious cycles; 0.5 is the balance coefficient, to ensure , the denominator is 1.5 in the normal state, so that the molecular life factor can function normally.

[0060] Harmonic correction term: The power grid harmonic distortion rate, The higher the harmonic interference, the smaller the value, The lower the value. This is because harmonics can cause voltage and current sampling values to be distorted, leading to false positives. Therefore, by reducing The value increases the switching threshold to resist harmonic interference; 0.3 is the harmonic influence weight, determined based on the impact of harmonics on sampling accuracy in actual tests. The overall formula converts switch state, copper bar performance, and power grid quality into quantifiable correction coefficients through the coordinated action of the numerator, denominator, and harmonic term, allowing the switching decision to respond to real.

[0061] This scheme realizes dynamic adjustment of the switching threshold by constructing a correction coefficient Solves the problem of poor adaptability of traditional fixed thresholds - when The value is small, The value decreases, the switching threshold is more stringent, reducing unnecessary switching; when The value is large, the denominator increases, reducing The value avoids frequent switching that exacerbates contact resistance growth; when The value is high, The term reduces The value increases the switching threshold to resist harmonic interference.

[0062] From the control logic perspective, this coefficient integrates multiple-dimensional parameters such as switch state, copper bar performance, and power grid quality into a single correction index, making the switching decision of the monitoring module more in line with actual operating conditions, reducing invalid switching while ensuring the accuracy of necessary switching.

[0063] The traditional technical solution has the following technical problems: the existing switch switching strategy does not combine the switching decision correction coefficient with the actual operation, even if the coefficient is calculated, it cannot be used to adjust the switching behavior, resulting in that the switch still switches according to the conventional logic in the case of short remaining life and large contact resistance, accelerating the damage of the switch and the growth of the contact resistance; at the same time, there is no priority power supply strategy for different operating states, which cannot protect the key equipment while ensuring power supply continuity.

[0064] Based on this, the monitoring module combines the switching decision correction coefficient with the control instruction generation process, when detecting abnormal power supply or bus electrical parameters, the actual switching trigger threshold is the product of the reference threshold and , when , the monitoring module automatically selects the third input power supply as the power supply to reduce the switching frequency of the switch, and when , the monitoring module adjusts the copper bar passing current by controlling the closing state of the tie switch 5 to reduce the growth rate of the real-time contact resistance of the copper bar.

[0065] This scheme solves the problem of disconnection between the traditional coefficient and the operation by converting the correction coefficient into the actual switching threshold adjustment, makes the switching decision more adaptive-the actual switching trigger threshold changes dynamically with , ensures that it does not switch easily when the harmonic interference is strong, and responds normally to faults when the switch life is sufficient; for the case of insufficient switch life, the third input power supply is preferentially selected to reduce the switching frequency of the switches 1 and 2 and prolong their service life; for the case of excessive contact resistance, the tie switch 5 is used to shunt the copper bar current to reduce the generation of Joule heat and alleviate the growth of contact resistance. From the perspective of system cooperation, this scheme realizes the closed-loop control of "parameter calculation-decision correction-operation execution", combines switch protection, copper bar protection and power supply continuity protection, avoids the premature failure of key components, ensures the stable operation of the power supply system, and makes the control logic more suitable for actual engineering needs.

[0066] The above is only a preferred embodiment of the present application, and does not limit the form of the present application, any person skilled in the art can use the disclosed technical content to make changes or modifications to equivalent embodiments applied to other fields, but any simple modification, equivalent change and modification made according to the technical essence of the present application to the above embodiments within the technical solution content of the present application still belongs to the protection scope of the present application.

Claims

1. A method for controlling 3 power supplies and 2 bus sections with 5 switches, characterized in that: The following steps are involved: Connect three input power sources to two bus sections through five switches. The first input power source is connected to bus section I through switch 1, the second input power source is connected to bus section II through switch 2, and the third input power source is connected to bus section I and bus section II through switches 3 and 4, respectively. Bus sections I and II are connected through tie switch 5. The electrical parameters of the three input power supplies and the two bus sections are collected by the power sampling device, and the power sampling device transmits the collected electrical parameters to the monitoring module via the sampling CAN communication bus; After analyzing and processing the electrical parameters, the monitoring module generates control instructions according to the preset control logic, which are transmitted to the operating mechanism via the control CAN communication bus. The operating mechanism controls the closing and opening of the five switches. The monitoring module also communicates with the remote control end via the remote control communication line, receives remote control operation instructions and executes corresponding switch control, wherein the preset control logic includes three power supply modes, and each power supply mode automatically switches the switch's closed and open states according to the fault status of the three input power supplies and the switch maintenance requirements.

2. The method of controlling 3 power supplies and 2 bus sections with 5 switches according to claim 1, characterized in that: The electrical parameters collected by the power sampling device include voltage, current, phase, frequency, active power, reactive power and power factor. The electrical parameters of the first input power supply are collected by the power sampling device arranged at the input end of switch 1, the electrical parameters of the second input power supply are collected by the power sampling device arranged at the input end of switch 2, and the electrical parameters of the third input power supply are collected by the power sampling device arranged at the input ends of switches 3 and 4. The electrical parameters of bus section I and bus section II are collected by the power sampling devices arranged on bus section I and bus section II respectively.

3. The method of controlling 3 power supplies and 2 bus sections with 5 switches according to claim 1, characterized in that: The three power supply modes include: the first power supply mode is that under normal conditions, the first input power supply supplies power to the bus section I and the second input power supply supplies power to the bus section II. When the first input power supply fails, the second input power supply supplies power to the bus section I through switch 2 and contact switch 5. When the second input power supply fails, the first input power supply supplies power to the bus section II through switch 1 and contact switch 5, and the third input power supply serves as a backup. The second power supply mode is that under normal conditions, the first input power supply supplies power to the bus section I and the second input power supply supplies power to the bus section II. The power supply supplies power to bus section II. When the 1st input power supply fails, the 3rd input power supply will give priority to supplying power to bus section I through switch 3. When the 2nd input power supply fails, the 3rd input power supply will give priority to supplying power to bus section II through switch 4. When the 3rd input power supply fails, the 1st input power supply and the 2nd input power supply serve as backup for each other. The third power supply mode is that when the 1st or 2nd input power supply fails or the switch is under maintenance, the 3rd input power supply will supply power to the 2nd bus sections through the corresponding switch and the connecting switch according to the switch maintenance requirements.

4. The method of controlling 3 power supplies and 2 bus sections with 5 switches according to claim 3, characterized in that: In the first power supply mode, when both the first input power supply and the second input power supply are normal, switch 1 and switch 2 are closed, and switch 3, switch 4, and contact switch 5 are opened; when the first input power supply fails and the second input power supply is normal, switch 2 and contact switch 5 are closed, and switch 1, switch 3, and switch 4 are opened; When the first input power supply is normal and the second input power supply fails, switch 1 and contact switch 5 are closed, and switches 2, 3, and 4 are opened; When both the first and second input power supplies fail and the third input power supply is normal, switches 3 and 4 are closed, and switches 1, 2, and contact switch 5 are opened.

5. The method of controlling 3 power supplies and 2 bus sections with 5 switches according to claim 3, characterized in that: In the second power supply mode, when the first input power fails, the second input power is normal, and the third input power is normal, switches 2 and 3 are closed, and switches 1, 4, and tie switch 5 are opened; When the first input power fails, the second input power is normal, and the third input power fails, switch 2 and contact switch 5 are closed, and switch 1, switch 3, and switch 4 are opened; When the first input power supply is normal, the second input power supply is faulty, and the third input power supply is normal, switches 1 and 4 are closed, and switches 2, 3, and tie switch 5 are opened; When the first input power supply is normal, the second input power supply fails, and the third input power supply fails, switch 1 and contact switch 5 are closed, and switches 2, 3, and 4 are opened.

6. The method of controlling 3 power supplies and 2 bus sections with 5 switches according to claim 1, characterized in that: The operating mechanism includes five independent operating units corresponding to control switches 1 to 5 respectively. Each operating unit is connected to the monitoring module via the control CAN communication bus, receives control instructions sent by the monitoring module and drives the corresponding switch to perform closing or opening actions. The working power supply of the operating mechanism is a 220V DC uninterruptible power supply, which is jointly provided by the station DC power supply and battery.

7. The method of controlling three power supplies and two bus sections with five switches according to claim 1, characterized in that: When generating control instructions, the monitoring module must first calculate the remaining life of the switch based on the cumulative number of switch switching times, operating temperature, and grid harmonic distortion rate. The calculation formula is: ； in, is the remaining mechanical life of the switch, is the rated mechanical life of the switch, is the actual cumulative number of switching times of the switch, is the rated switching times of the switch, is the temperature influence coefficient, is the current operating temperature of the switch, is the reference temperature, is the harmonic influence coefficient, is the total harmonic distortion rate of the power grid.

8. The method of controlling three power supplies and two bus sections with five switches according to claim 7, characterized in that: The monitoring module also needs to calculate the real-time contact resistance based on the initial contact resistance of the copper busbar, the operating temperature and the current passing through it. The calculation formula is: ； in, is the copper busbar contact resistance at time t, is the initial contact resistance of the copper busbar, is the thermal expansion coefficient of the copper bar, is the current working temperature of the copper busbar, is the reference temperature, is the Joule heat influence coefficient, is the real-time current passing through the copper busbar, for The copper busbar contact resistance at the moment, To calculate the duration.

9. The method of controlling three power supplies and two bus sections with five switches according to claim 8, characterized in that: The monitoring module calculates the switching decision correction coefficient based on the remaining life of the switch, the real-time contact resistance of the copper busbar, and the harmonic distortion rate of the power grid to adjust the switch switching trigger threshold. The calculation formula is: ； in, is the switching decision correction coefficient, is the remaining mechanical life of the switch, is the rated mechanical life of the switch, is the copper busbar contact resistance at time t, is the initial contact resistance of the copper busbar, is the total harmonic distortion rate of the power grid.

10. The method of controlling three power supplies and two bus sections with five switches according to claim 9, characterized in that: The monitoring module will switch the decision correction coefficient Applied to the control instruction generation process, when the power supply or busbar electrical parameter abnormality is detected, the actual switching trigger threshold is the reference threshold and The product of When the monitoring module automatically selects the third input power as the power supply to reduce the number of switching times, When the contact switch 5 is closed, the monitoring module adjusts the current passing through the copper busbar to reduce the growth rate of the copper busbar's real-time contact resistance.

Images