A method for 5-switch control of 3-way power 2-section bus

Abstract

The present application relates to the technical field of power distribution, and more particularly to a method for controlling 3 power supply lines with 2 bus sections by 5 switches, comprising the following steps: connecting 3 input power supply lines with 2 bus sections by 5 switches, wherein the first input power supply line is connected to the first bus section through switch 1, the second input power supply line is connected to the second bus section through switch 2, the third input power supply line is connected to the first bus section and the second bus section through switch 3 and switch 4 respectively, and the first bus section and the second bus section are connected through tie switch 5; collecting electrical parameters of the 3 input power supply lines and the 2 bus sections by a power supply sampling device, and transmitting the collected electrical parameters to a monitoring module through a CAN communication bus for sampling; and generating control instructions according to a preset control logic after analyzing and processing the electrical parameters by the monitoring module, and transmitting the control instructions to an operating mechanism through a CAN communication bus for control. The present application can solve the problems of insufficient power supply reliability and poor economy in the prior art.

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, one of which contains two switches, and the actual number of switches is relatively large, equivalent to 10 switches, which increases the electrical loop links, the copper consumption of cross-cabinet connection, and the cost of switches. 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 may prolong 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 problems existing 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:

[0005] 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;

[0006] 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;

[0007] 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;

[0008] 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.

[0009] 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 section bus and the second section bus are collected by the power supply sampling devices arranged on the first section bus and the second section bus respectively.

[0010] Further preferably, the three power supply modes include: in the first power supply mode, the first input power source supplies power to the first section bus and the second input power source supplies power to the second section bus in the normal state, when the first input power source fails, the second input power source supplies power to the first section bus through switch 2 and tie switch 5, when the second input power source fails, the first input power source supplies power to the second section bus through switch 1 and tie switch 5, 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 section bus and the second input power source supplies power to the second section bus in the normal state, when the first input power source fails, the third input power source supplies power to the first section bus through switch 3, when the second input power source fails, the third input power source supplies power to the second section bus through switch 4, and when the third input power source fails, the first input power source and the second input power source serve as backups for each other; in the third power supply mode, when the first input power source and the second input power source fail or the switches need to be maintained, the third input power source supplies power to the two section buses through the corresponding switches and tie switches according to the switch maintenance requirements.

[0011] 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.

[0012] 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.

[0013] 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 a 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 a station direct current power supply and a storage battery.

[0014] 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:

[0015] ;

[0016] Among them, is the switch residual mechanical life, is the switch rated mechanical life, is the switch actual cumulative switching times, is the switch rated switching times, is the temperature influence coefficient, is the switch current working temperature, is the reference temperature, is the harmonic influence coefficient, is the power grid total harmonic distortion rate.

[0017] 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:

[0018] ;

[0019] Among them, is the copper bar contact resistance at t moment, is the copper bar initial contact resistance, is the copper bar thermal expansion coefficient, is the current working temperature of the copper bar, is the reference temperature, is the joule heat influence coefficient, is the real-time current passing through the copper bar, is the copper bar contact resistance at time t, is the calculation duration.

[0020] 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 harmonic distortion rate of the power grid, which is used to adjust the switching trigger threshold value, and the calculation formula is:

[0021] ;

[0022] 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.

[0023] Further preferably, the monitoring module applies the switching decision correction coefficient to the control instruction 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.

[0024] Technical effects:

[0025] The present application connects 3 power supplies and 2 bus sections through 5 switches, replaces the traditional ATS and multiple switches, reduces the number of switches and copper bars, reduces the cost and the electrical circuit link; with the help of the power supply sampling device, the monitoring module and the CAN communication, automatic control is realized without 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

[0026] Figure 1 is the method principle diagram of the present application for controlling 3 power supplies and 2 bus sections through 5 switches;

[0027] Figure 2 is the first switch state diagram of the first power supply mode of the present application;

[0028] Figure 3 The third switching state diagram for the first power supply mode of the present application;

[0029] Figure 4 The fourth switching state diagram for the first power supply mode of the present application;

[0030] Figure 5 The fifth switching state diagram for the first power supply mode of the present application;

[0031] Figure 6 The first switching state diagram for the second power supply mode of the present application;

[0032] Figure 7 The second switching state diagram for the second power supply mode of the present application;

[0033] Figure 8 The third switching state diagram for the second power supply mode of the present application;

[0034] Figure 9 The fourth switching state diagram for the second power supply mode of the present application;

[0035] Figure 10 The fifth switching state diagram for the second power supply mode of the present application;

[0036] Figure 11 The sixth switching state diagram for the second power supply mode of the present application;

[0037] Figure 12 The first switching state diagram for the third power supply mode of the present application;

[0038] Figure 13 The second switching state diagram for the third power supply mode of the present application;

[0039] Figure 14 The third switching state diagram for the third power supply mode of the present application.

[0040] In the figure:

[0041] 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 Implementation

[0042] To make the objectives, technical solutions, and advantages of this invention clearer, the invention 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 merely illustrative and not intended to limit the invention.

[0043] Traditional technical solutions have the following technical problems: In the control of 3 power sources and 2 bus sections, the existing solution usually uses 2 ATS plus multiple switches. The ATS contains 2 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 cost, but also has the problem of untimely switching. At the same time, the switching logic is fixed when the power supply fails, and it cannot be flexibly adjusted according to priority. Moreover, it lacks an automatic control mechanism, and relying on manual operation can easily prolong the power outage time. In scenarios such as important substations, the power supply reliability is insufficient.

[0044] Based on this, this embodiment provides a method for controlling three power supplies and two bus sections using five switches, comprising the following steps: connecting three input power supplies to two bus sections via five switches, wherein the first input power supply is connected to bus section I via switch 1, the second input power supply is connected to bus section II via switch 2, and the third input power supply is connected to bus section I and bus section II via switches 3 and 4 respectively, with bus section I and bus section II connected via a tie switch 5; collecting electrical parameters of the three input power supplies and two bus sections using a power sampling device, and transmitting the collected electrical parameters to a monitoring module via a CAN communication bus; the monitoring module analyzes and processes the electrical parameters, generates control commands according to preset control logic, and transmits them to an operating mechanism via a CAN communication bus, which then 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 commands, and executes corresponding switch controls, 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 status of the three input power supplies and the switch maintenance requirements.

[0045] The scheme reduces the number of switches by a specific connection structure of 5 switches, replaces the traditional ATS, reduces the cost and loop links; with the help of CAN communication between the power sampling device and the monitoring module, real-time parameter acquisition and automatic analysis are realized, combined with the preset control logic to realize automatic switching of the switch, without manual operation; the design of 3 power supply modes makes the power supply switching flexible according to the priority, solves the problem of fixed switching logic and manual operation of the existing scheme. From the perspective of electrical system, the CAN communication bus for sampling ensures the real-time and reliability of parameter transmission, the CAN communication bus for control realizes the accurate issuance of control instructions, and the communication between the monitoring module and the remote control end expands the control flexibility. Through the combination of hardware connection and software logic, the high reliability and low cost of power supply are realized.

[0046] The traditional technical scheme has the following technical problems: in the existing 3-way power supply and 2-section bus control, the sampling range of the power 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 makes it impossible to comprehensively judge the running state of the power supply and the bus, and easy to cause fault misjudgment or omission; at the same time, the installation position of the sampling device is unreasonable, it is difficult to accurately obtain the real parameters of the input end of each power supply and the bus, which affects the judgment accuracy of the monitoring module to the fault state.

[0047] Based on this, the electrical parameters collected by the power 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 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, the electrical parameters of the third input power supply are collected by the power 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 sampling device arranged on section I bus and section II bus respectively.

[0048] The scheme covers the core indicators of the running state of the power supply and the bus by specifying the types of sampling parameters, the phase and frequency parameters can avoid the parallel risk of the power supply, the active power, the reactive power and the power factor can reflect the running efficiency of the load, and solve the one-sided problem of state judgment caused by incomplete parameter collection of 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, providing accurate data for fault judgment of the monitoring module.

[0049] From the perspective of electricity, complete parameter collection provides a 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 control, and the targeted design of sampling position reduces the influence of line loss on parameters, improving the sampling accuracy.

[0050] 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 prone to occur; at the same time, there is a lack of detailed power supply strategy for different fault scenarios, in different scenarios such as 1-way or 2-way power supply failure or switch maintenance, the switching logic is fixed and cannot adapt to the actual demand, resulting in the continuity of power supply being affected.

[0051] Therefore, the three power supply modes include: the first power supply mode is that the first input power supply supplies power to the I section bus and the second input power supply supplies power to the II section bus in the normal state, when the first input power supply fails, the second input power supply supplies power to the I section bus through switch 2 and tie switch 5, when the second input power supply fails, the first input power supply supplies power to the II section bus through switch 1 and tie switch 5, and the third input power supply is used as a backup; the second power supply mode is that the first input power supply supplies power to the I section bus and the second input power supply supplies power to the II section bus in the normal state, when the first input power supply fails, the third input power supply supplies power to the I section bus through switch 3, when the second input power supply fails, the third input power supply supplies power to the II section bus through switch 4, and when the third input power supply fails, the first input power supply and the second input power supply are used as backups for each other; and the third power supply mode is that when the first input power supply and the second input power supply fail or the switch needs to be maintained, the third input power supply supplies power to the two section buses through the corresponding switch and tie switch according to the switch maintenance requirement.

[0052] The scheme solves the problem of unclear switching priority of the existing scheme by subdividing the three power supply modes and designing clear switching logic for different fault scenarios; the power supply switching path in each mode is clear, and the closing and opening states of the switch are combined to ensure that the target power supply can be quickly switched in the event of a fault, thereby reducing the power outage time.

[0053] From the perspective of control logic, the design of the power supply mode realizes the flexibility of the switching strategy, which can select the appropriate mode according to the actual demand, such as selecting the second mode in the scenario where the reliability of the three power supplies is high, and selecting the third mode in the scenario where the switch needs to be frequently maintained, thereby improving the adaptability of the system through the subdivision of the logic level.

[0054] The prior art has the following technical problems: in the actual application of the first power supply mode, the existing scheme does not clearly define the switch action logic under different fault states, when 1-way or 2-way power supply fails, the closing and opening states of the switch lack standardization, and misoperation is prone to occur, resulting in power supply in parallel or bus power failure; at the same time, the correspondence between the switch state and the power supply failure is not clear, the monitoring module cannot accurately execute the switching instruction, and the continuity of power supply is affected.

[0055] 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.

[0056] The scheme establishes clear action logic by clearly defining the switch state corresponding to different fault states in the first power supply mode, solves the problem of non-standard switch operation in the existing scheme, and avoids parallel connection of the three power supplies in each fault state. Parallel connection of the three power supplies may cause short circuit risk due to inconsistent phase and frequency, and ensures power supply safety. From the perspective of electrical safety, the precise design of the switch state prevents power supply conflicts, such as closing only switch 1 and switch 2 in the normal state to ensure that the first input power supply and the second input power supply supply power respectively without parallel connection; and closing contact switch 5 to realize power supply across the bus during fault, while disconnecting the switch corresponding to the faulty power supply to avoid the influence of the faulty power supply on the bus, thereby ensuring the reliability of power supply through standard hardware action.

[0057] 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 the switch state is chaotic when one of the three power supplies is faulty and the third input power supply is normal, which may cause interruption of power supply to the target bus; at the same time, the switching logic after failure of the third input power supply is not clear, and the effective execution of the first input power supply and the second input power supply as backups for each other cannot be ensured, affecting power supply continuity.

[0058] 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.

[0059] The scheme establishes a clear switching path with the third input power supply as the priority backup 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 backup when the third input power supply fails, ensuring uninterrupted power supply. From the perspective of power utilization efficiency, the logic fully utilizes the backup 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.

[0060] 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.

[0061] 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.

[0062] 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 switch operation, and provides hardware support for continuous operation of the power supply system.

[0063] 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.

[0064] 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:

[0065] ;

[0066] 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.

[0067] 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.

[0068] is the rated mechanical life calibrated when the switch is shipped, which is determined by the manufacturer according to the mechanical structure of the switch, such as contact material and spring strength, and is the reference value for life evaluation. is the actual cumulative switching times of the switch from being put into use to the present, which directly reflects the degree of mechanical wear and tear - each switching will cause contact of the contacts and expansion and contraction of the springs, and the more the number of times, the more serious the wear and tear, so is used to quantify the proportion of life consumption caused by mechanical wear and tear.

[0069] is the temperature influence coefficient, and the value is , which is used to convert temperature changes into life consumption factors. is the current working temperature of the switch, is the reference temperature, Reflect the degree of temperature deviation from the reference value: temperature rise will accelerate the aging of the switch internal lubricating grease, metal parts oxidation, and the higher the temperature, the more significant the impact, the square term amplifies the nonlinear impact of high temperature, so this term is used to quantify the additional consumption of temperature on life.

[0070] is the harmonic influence coefficient, taking 0.05, is the total harmonic distortion of the power grid, reflecting the content of high-order harmonics in the power grid except the fundamental wave. Harmonics will cause additional high-frequency current on the switch contacts, leading to contact heating and 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 is used to quantify the consumption of harmonics on life.

[0071] 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.

[0072] The scheme introduces two key factors of temperature and harmonic to build a life calculation model that is more in line with the actual operation scenario, solving the one-sidedness of the traditional method of evaluating life only according to the number of switching - temperature rise will lead to the decline of switch internal lubricating grease performance and the aggravation of mechanical wear, while the high-frequency current generated by harmonics will accelerate the oxidation of contacts, 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 impact of harmonics; the monitoring module can grasp the switch state in real time based on the calculation results, and give early warning when the remaining life is low, facilitating the planned maintenance of operation and maintenance personnel. From the perspective of electrical and mechanical combination, the 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 judgment to data-driven accurate prediction, providing a scientific basis for the reliable operation of the switch.

[0073] The traditional technical scheme has the following technical problems: the existing copper bar contact resistance monitoring mostly adopts periodic manual measurement method, which cannot reflect the dynamic change of contact resistance in real time, and does not consider the change of contact pressure caused by thermal expansion of the copper bar, and the resistance increase 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 operation state of the power supply system, and cannot take intervention measures in advance.

[0074] Based on this, the monitoring module also needs to calculate the real-time contact resistance based on the initial contact resistance of the copper bar, the working temperature and the passing current, and the calculation formula is:

[0075] ;

[0076] Wherein, is the contact resistance of the copper bar at time t, is the initial contact resistance of the copper bar, is the thermal expansion coefficient of the copper bar, is the current working temperature of the copper bar, is the reference temperature, is the Joule heat influence coefficient, is the real-time current passing through the copper bar, is the contact resistance of the copper bar at time t, is the calculation duration.

[0077] In the formula, is the contact resistance of the copper bar at the current time, which directly affects the conductivity and heating state of the copper bar. is the contact resistance after the initial installation of the copper bar, which is determined by the installation pressure and the flatness of the contact surface, and is the reference value for resistance calculation.

[0078] is the thermal expansion coefficient of the copper bar, which is a physical property inherent to copper materials. is the current working temperature of the copper bar, is the reference temperature, is used to quantify the influence of temperature on contact resistance: when the temperature rises, the copper bar expands due to heat, which will reduce the contact surface pressure and increase the contact resistance; on the contrary, when the temperature decreases, the copper bar will contract due to heat, which will increase the contact surface pressure and decrease the contact resistance, so this item directly reflects the resistance change caused by thermal expansion.

[0079] is the Joule heat influence coefficient, which is used to convert the cumulative amount of Joule heat into a resistance change factor.

[0080] is the integral of Joule heat from the initial time to the current time: is the real-time current passing through the copper bar, is the contact resistance at a certain time, is the instantaneous heat power, and the integral gives the cumulative heat. Heat accumulation will cause the temperature of the copper bar to rise, further aggravating thermal expansion, and at the same time 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 growth rate of resistance will slow down, because the thickness of the oxidation film tends to be stable.

[0081] In the overall formula, The correction term in the bracket is multiplied to obtain the real-time contact resistance: the first term "1" in the bracket is the reference, the second term is the resistance increment ratio caused by thermal expansion, and the third term is the resistance increment ratio caused by Joule heat. The superposition of the three accurately reflects the dynamic change of the contact resistance with temperature and current, and provides data support for preventing copper bar overheating.

[0082] The scheme realizes real-time dynamic calculation of the contact resistance by introducing the thermal expansion coefficient and the integral term of Joule heat, solves the problem of the hysteresis of traditional manual measurement, and accurately captures the cumulative effect of the positive feedback cycle of resistance increase, heat increase, and further resistance increase caused by the decrease of contact point pressure due to thermal expansion and the increase of temperature caused by Joule heat generated when the current passes. The monitoring module can master the change trend of the contact resistance through real-time calculation, and provide basis for subsequent switching decision. From the perspective of electrical and thermal coupling, the model relates the physical properties, electrical parameters and resistance change of the copper bar, making the contact resistance which is originally difficult to directly monitor become a quantifiable index, and providing data support for preventing copper bar overheating and ensuring power supply safety.

[0083] The traditional technical scheme has the following technical problems: the existing switching trigger threshold is a fixed value, and the influence of the actual operating state such as the remaining life of the switch, the contact resistance of the copper bar and the grid harmonic is not considered. 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.

[0084] Therefore, 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 grid harmonic distortion rate, which is used to adjust the switching trigger threshold of the switch, and the calculation formula is:

[0085] ;

[0086] 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 contact resistance of the copper bar at time t, is the initial contact resistance of the copper bar, is the total harmonic distortion rate of the grid.

[0087] The switching decision correction coefficient directly determines the adjustment range of the actual switching trigger threshold, and is the core parameter of balancing switching accuracy and equipment protection.

[0088] Molecule Switch remaining life proportion: when the value is close to 1, the switch life is sufficient, the molecule is larger, the value is high, and the switch is switched according to the conventional threshold; when the value is small, the switch life is insufficient, and the molecule is reduced, the value is reduced, the switching threshold is more stringent, and unnecessary switching is reduced to protect the switch.

[0089] Denominator For associated copper bar contact resistance state: is the ratio of the current contact resistance to the initial resistance, the larger the value, the larger the contact resistance, and the larger the denominator, the lower the value.

[0090] Because when the contact resistance is large, frequent switching will cause current fluctuations, further exacerbating resistance growth, so by reducing the value reduces switching to avoid a vicious cycle; 0.5 is a balance coefficient to ensure , the denominator is 1.5 in the normal state, so that the life factor of the molecule can normally play a role.

[0091] Harmonic correction term: is the power grid harmonic distortion rate, the higher the value, the stronger the harmonic interference, the smaller the value of this term, the lower the value. This is because harmonics can cause voltage and current sampling values to be distorted, misjudging as a fault, so by reducing the value increases the switching threshold to resist harmonic interference; 0.3 is the harmonic influence weight, which is determined based on the influence degree of harmonics on sampling accuracy in actual tests. The overall formula converts switch state, copper performance, and power grid quality into quantifiable correction coefficients through the coordinated action of the numerator, denominator, and harmonic term, so that the switching decision can respond to the real.

[0092] This scheme realizes the dynamic adjustment of the switching threshold by constructing the correction coefficient , solves the problem of poor adaptability of the traditional fixed threshold - when is small, the value is reduced, the switching threshold is more stringent, and unnecessary switching is reduced; when is large, the denominator is increased to reduce the value, to avoid frequent switching causing current fluctuations to exacerbate contact resistance growth; when is high, the term reduces the value to increase the switching threshold to resist harmonic interference.

[0093] From a control logic perspective, this coefficient integrates multiple parameters such as switch status, copper bus performance, and power grid quality into a single correction index, making the switching decisions of the monitoring module more in line with the actual operating conditions. This reduces invalid switching while ensuring the accuracy of necessary switching.

[0094] Traditional technical solutions have the following technical problems: existing switch switching strategies do not combine the switching decision correction coefficient with actual operation. Even if the coefficient is calculated, it cannot be used to adjust the switching behavior, causing the switch to switch according to the conventional logic even when the remaining life is short and the contact resistance is high, which accelerates switch damage and contact resistance growth. At the same time, there is a lack of priority power supply strategies for different operating states, which cannot protect critical equipment while ensuring power supply continuity.

[0095] Based on this, the monitoring module will switch the decision correction coefficient. Applied to the control command generation process, when an abnormality is detected in the power supply or bus electrical parameters, the actual switching trigger threshold is the base threshold and... The product of, when When this happens, the monitoring module automatically prioritizes the third input power supply to reduce the number of switching operations. At that time, the monitoring module adjusts the current passing through the copper busbar by controlling the closed state of the contact switch 5, thereby reducing the rate of increase in the real-time contact resistance of the copper busbar.

[0096] This scheme uses a correction factor This translates into actual handover threshold adjustment, resolving the disconnect between traditional coefficients and operational procedures, and making handover decisions more adaptive—the actual handover trigger threshold adjusts accordingly. Dynamic adjustments ensure that switching is not easily initiated under strong harmonic interference and that fault response is normal when the switch life is sufficient. For cases of insufficient switch life, prioritizing the third input power supply reduces the number of switching operations between switches 1 and 2, extending their lifespan. For cases of excessive contact resistance, the copper busbar current is reduced by shunting through the tie switch 5, minimizing Joule heating and mitigating contact resistance increases. From a system coordination perspective, this solution achieves closed-loop control of "parameter calculation - decision correction - operation execution," combining switch protection, copper busbar protection, and power supply continuity assurance. This avoids premature failure of critical components and ensures stable operation of the power supply system, making the control logic more aligned with actual engineering needs.

[0097] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments that can be applied to other fields. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A method of 5-switch controlling a 3-way power 2-section bus, characterized in that, The method comprises the following steps: Three input power sources are connected to two bus sections through five switches, wherein the first input power source is connected to the first bus section through switch 1, the second input power source is connected to the second bus section through switch 2, and the third input power source is connected to the first bus section and the second bus section through switch 3 and switch 4 respectively, and the first bus section and the second bus section are connected through tie switch 5; The electrical parameters of the three input power sources and the two bus sections are collected through a power sampling device, and the collected electrical parameters are transmitted to a monitoring module through a CAN communication bus for sampling; After analyzing and processing the electrical parameters, the monitoring module generates control instructions according to a preset control logic, and the control instructions are transmitted to an operating mechanism through a 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 end through a 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 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 in each power supply mode; When generating the control instructions, the monitoring module needs to calculate the switch residual life based on the cumulative switching times, the working temperature and the power grid harmonic distortion rate of the switches, and the calculation formula is: ； wherein, is the remaining mechanical life of the switch, is the rated mechanical life of the switch, is the actual cumulative switching number of the switch, is the rated switching number 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 of the power grid.

2. The method of claim 1, wherein, The electrical parameters collected by the power 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 sampling device arranged at the input end of switch 1, the electrical parameters of the second input power source are collected by the power sampling device arranged at the input end of switch 2, the electrical parameters of the third input power source are collected by the power sampling device arranged at the input ends of switch 3 and switch 4, and the electrical parameters of the first bus section and the second bus section are collected by the power sampling devices arranged on the first bus section and the second bus section respectively.

3. The method of claim 1, wherein, The three power supply modes include: the first power supply mode is that the first input power source supplies power to the first bus section and the second input power source supplies power to the second bus section in the normal state, the second input power source supplies power to the first bus section 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 section through switch 1 and tie switch 5 when the second input power source fails, and the third input power source is used as a backup; the second power supply mode is that the first input power source supplies power to the first bus section and the second input power source supplies power to the second bus section in the normal state, the third input power source supplies power to the first bus section through switch 3 when the first input power source fails, the third input power source supplies power to the second bus section through switch 4 when the second input power source fails, and the first input power source and the second input power source are used as backups when the third input power source fails; and the third power supply mode is that the third input power source supplies power to the two bus sections through the corresponding switches and tie switch when the first input power source and the second input power source fail or the switches are under maintenance.

4. The method of claim 3, wherein, In the first power supply mode, when the first and second input power sources are normal, the switch 1 and the switch 2 are closed, and the switch 3, the switch 4 and the contact switch 5 are disconnected; when the first input power source is faulty and the second input power source is normal, 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 source is normal and the second input power source is faulty, the switch 1 and the contact switch 5 are closed, and the switch 2, the switch 3 and the switch 4 are disconnected; When the first and second input power sources are both faulty and the third input power source is normal, the switch 3 and the switch 4 are closed, and the switch 1, the switch 2 and the contact switch 5 are disconnected.

5. The method of claim 3, wherein, In the second power supply mode, when the first input power source is faulty, the second input power source is normal and the third input power source 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 source is faulty, the second input power source is normal and the third input power source is faulty, 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 source is normal, the second input power source is faulty and the third input power source 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 source is normal, the second input power source is faulty and the third input power source is faulty, the switch 1 and the contact switch 5 are closed, and the switch 2, the switch 3 and the switch 4 are disconnected.

6. The method of claim 1, wherein, The operation mechanism comprises five independent operation units corresponding to the switch 1 to the switch 5 respectively, each operation unit is connected with the monitoring module through a 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 operation mechanism is a 220V direct current uninterrupted power supply, which is jointly provided by a station direct current power supply and a storage battery.

7. The method of claim 6, wherein, The monitoring module also needs to calculate the real-time contact resistance based on the initial contact resistance, the working temperature and the passing current of the copper bar, and the calculation formula is: ； wherein, is the copper bar contact resistance at time t, is the initial copper bar contact resistance, is the copper bar thermal expansion coefficient, is the current operating temperature of the copper bar, is the reference temperature, is the Joule heating influence coefficient, is the real-time current through the copper bar, is the copper bar contact resistance at time t, is the calculation duration.

8. The method of claim 7, wherein, The monitoring module calculates the switching decision correction coefficient based on the residual life of the switch, the real-time contact resistance of the copper bar and the power grid harmonic distortion rate, which is used for adjusting the switching trigger threshold, and the calculation formula is: The monitoring module calculates the switching decision correction coefficient based on the residual life of the switch, the real-time contact resistance of the copper bar and the power grid harmonic distortion rate, which is used for adjusting the switching trigger threshold, and the calculation formula is: ； wherein, is a switching decision correction factor, is a switch residual mechanical life, is a switch rated mechanical life, is a copper bar contact resistance at time t, is a copper bar initial contact resistance, is a total harmonic distortion of the power grid.

9. The method of claim 8, wherein, The monitoring module will modify the switching decision coefficient The monitoring module will modify the switching decision coefficient The monitoring module will modify the switching decision coefficient When the monitoring module detects the abnormality of the power supply or bus electrical parameters, the actual switching trigger threshold is the product of the reference threshold and the switching decision coefficient, and when the actual switching trigger threshold is greater than the reference threshold, the monitoring module automatically selects the third input power supply as the power supply to reduce the switching frequency. When the monitoring module detects the abnormality of the power supply or bus electrical parameters, the actual switching trigger threshold is the product of the reference threshold and the switching decision coefficient, and when the actual switching trigger threshold is greater than the reference threshold, the monitoring module automatically selects the third input power supply as the power supply to reduce the switching frequency.

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