A box transformer comprehensive measurement and control protection method integrating electrical quantity and non-electrical quantity monitoring

Abstract

The application discloses a kind of integrated electrical quantity and non-electrical quantity monitoring's box transformer comprehensive measurement and control protection method includes, the electrical analog quantity of box transformer is collected, and it is discriminated based on preset electrical quantity protection logic, generates electrical quantity protection judgment result;Collect the non-electrical quantity state signal reflecting the state of transformer body, and it is discriminated based on preset non-electrical quantity protection logic, generates non-electrical quantity protection judgment result;According to electrical quantity protection judgment result and non-electrical quantity protection judgment result, it is comprehensively protected decision by collaborative decision logic, determine whether to satisfy preset protection action condition;When comprehensive protection decision result is to satisfy protection action condition, output control instruction to drive associated circuit breaker action;The application places electrical quantity and non-electrical quantity information under unified collaborative decision framework, realizes the overall, fast response to box transformer fault, effectively improves the reliability and accuracy of protection, avoids the misoperation or refusal to move possibly caused by single information source.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of power system relay protection, and in particular to a box transformer comprehensive measurement and control protection method integrating electrical quantity and non-electrical quantity monitoring. BACKGROUND

[0002] With the rapid development of distributed energy such as wind power and photovoltaic power generation, the safe and stable operation of box-type substations, which are the key hubs connecting new energy generation units and power grids, is crucial. In order to meet the high requirements of modern power grids for automation and reliability, the measurement and control protection technology for box-type substations has gradually developed from traditional single relay protection to integrated and intelligent microcomputer protection devices. These devices generally use embedded microprocessor technology, which can realize real-time monitoring of electrical quantities (such as current and voltage) in the box transformer, and perform conventional electrical quantity protection such as overcurrent and overvoltage. At the same time, through the communication interface, data transmission and remote control are realized, which adapts to the operation mode of "few people on duty" of the power station.

[0003] However, the existing technology still has deficiencies in realizing comprehensive protection of box-type substations. First, the monitoring and protection logic of electrical quantities and non-electrical quantities (such as transformer oil temperature, oil level, gas pressure, etc.) are often fragmented. Non-electrical quantity protection is usually an independent alarm or tripping input, lacking deep integration and collaborative decision-making mechanism with electrical quantity protection logic, resulting in limited comprehensive judgment ability of the protection system to faults, and single information dimension, making it difficult to accurately and quickly diagnose the internal relationship between electrical abnormalities and changes in device physical state. Second, some existing protection schemes are not fine and robust enough in abnormal condition discrimination. For example, when a voltage transformer (TV) secondary circuit is disconnected, if the detection logic is not perfect, it is easy to cause the misoperation or refusal of protection functions (such as low voltage and overvoltage protection) that rely on voltage criteria, posing a threat to system safety.

[0004] CN104836340A discloses an intelligent monitoring system and method for monitoring the operation of a box-type substation. This scheme combines smart grid technology and internet technology in box-type substations, introduces intelligent monitoring devices, reliable communication methods, and perfect communication protocols, and realizes self-identification, self-diagnosis, self-monitoring, and self-action of box-type substations. However, its scheme mainly relies on communication networking to monitor the operation of box-type substations, and does not mention the decision-making mechanism for electrical quantity protection and non-electrical quantity protection.

[0005] CN112993936B discloses a box-type substation integrated protection method, system, terminal and storage medium. The scheme calculates the starting line current mutation of the low-voltage outgoing line and the mutation of the high-voltage side current of the transformer, performs disconnect protection on the low-voltage outgoing line, the transformer and the low-voltage bus, and judges whether to perform delay disconnect protection on the transformer and the low-voltage bus according to the transformer low-voltage side current amplitude and the total amplitude of each low-voltage outgoing line current. Although the scheme mentions the protection measures of electrical quantities, the scheme mainly extends the multi-level protection to the end of the power system to improve the power supply reliability, but it lacks consideration of non-electrical quantity protection.

[0006] Therefore, there is an urgent need for a comprehensive protection method that can integrate electrical quantity and non-electrical quantity information, has unified and coordinated decision-making logic, and has high reliability discrimination ability for key abnormal working conditions. SUMMARY

[0007] This section aims to summarize some aspects of the embodiments of the present application and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the abstract and title of the specification to avoid obscuring the purpose of this section, abstract and title, and such simplifications or omissions cannot be used to limit the scope of the present application.

[0008] In view of the above existing problems, the present application is proposed. Therefore, the present application provides a box transformer comprehensive measurement and control protection method integrating electrical quantity and non-electrical quantity monitoring to solve the problems proposed in the background art.

[0009] To solve the above technical problems, the present application provides the following technical scheme: a box transformer comprehensive measurement and control protection method integrating electrical quantity and non-electrical quantity monitoring, comprising:

[0010] Collecting multiple electrical analog quantities and non-electrical quantity state signals in the box-type substation, comparing the collected electrical analog quantities with preset electrical quantity protection setting values, and generating electrical quantity protection judgment results according to electrical quantity protection logic;

[0011] Monitoring the non-electrical quantity state signals and generating non-electrical quantity protection judgment results according to non-electrical quantity protection logic;

[0012] Based on the electrical quantity protection judgment results and the non-electrical quantity protection judgment results, comprehensive protection decision is made to determine whether the preset protection action condition is met;

[0013] When the comprehensive protection decision meets the preset protection action condition, output a control instruction to drive the associated circuit breaker to act.

[0014] As a preferred scheme of the integrated electrical quantity and non-electrical quantity monitoring box transformer comprehensive measurement and control protection method, the method comprises the following steps:

[0015] Meanwhile, the electrical analog quantities of the high-voltage side and the low-voltage side of the box transformer substation are collected, and the collected electrical analog quantities are compared with preset electrical quantity protection setting values, and electrical quantity protection judgment results are generated according to electrical quantity protection logic.

[0016] As a preferred scheme of the integrated electrical quantity and non-electrical quantity monitoring box transformer comprehensive measurement and control protection method, the method comprises the following steps:

[0017] As a preferred scheme of the integrated electrical quantity and non-electrical quantity monitoring box transformer comprehensive measurement and control protection method, the method comprises the following steps:

[0018] The execution process is at least one protection judgment mode selected from the following: overcurrent protection judgment, zero sequence overcurrent protection judgment, overvoltage protection judgment, low voltage protection judgment and overload protection judgment.

[0019] As a preferred scheme of the integrated electrical quantity and non-electrical quantity monitoring box transformer comprehensive measurement and control protection method, the method comprises the following steps:

[0020] The calculated value of any phase current in the collected three-phase current is compared with at least one preset overcurrent setting value;

[0021] If the phase current calculated value is greater than the overcurrent setting value for a long time, start the delay timer;

[0022] When the delay timer reaches the preset time setting value corresponding to the overcurrent setting value, it is determined that the overcurrent protection condition is met.

[0023] As a preferred scheme of the integrated electrical quantity and non-electrical quantity monitoring box transformer comprehensive measurement and control protection method, the method comprises the following steps:

[0024] As a preferred scheme of the integrated electrical quantity and non-electrical quantity monitoring box transformer comprehensive measurement and control protection method, the method comprises the following steps:

[0025] After receiving the non-electric quantity state signal, the state of the protection tripping soft pad corresponding to the signal is inquired;

[0026] If the soft pad is in the tripped state, it is determined that the non-electric quantity protection action condition is met, and if the soft pad is in the tripped state, alarm information is generated.

[0027] As a preferred scheme of the integrated electric quantity and non-electric quantity monitoring box transformer comprehensive measurement and control protection method, after outputting the control instruction to drive the associated circuit breaker to act, the method further comprises the following steps:

[0028] Recording fault event information triggering the control instruction;

[0029] A preset time length before the fault occurrence time and all electric analog quantity waveform data of the preset time length after the fault occurrence time are intercepted and stored in the non-volatile memory.

[0030] As a preferred scheme of the integrated electric quantity and non-electric quantity monitoring box transformer comprehensive measurement and control protection method, the method further comprises a TV line break detection step, which is performed after the acquisition of the multi-channel electric analog quantity and non-electric quantity state signal in the box transformer substation, and comprises the following steps:

[0031] When it is detected that the three-phase phase voltages are all lower than a preset first voltage threshold and at least any one phase current is greater than a preset current threshold, it is determined as three-phase TV line break;

[0032] When it is detected that the sum of the three-phase voltages is greater than the first voltage threshold and the minimum line voltage is less than a preset second voltage threshold, it is determined as single-phase or two-phase TV line break;

[0033] When it is detected that the sum of the three-phase voltages is greater than the first voltage threshold and the difference between the maximum line voltage and the minimum line voltage is greater than the second voltage threshold, it is determined as single-phase or two-phase TV line break;

[0034] After determining the three-phase TV line break, the single-phase or two-phase TV line break, all electric quantity protection functions depending on voltage measurement are automatically locked.

[0035] As a preferred scheme of the integrated electric quantity and non-electric quantity monitoring box transformer comprehensive measurement and control protection method, the method further comprises a remote interaction step:

[0036] The real-time telemetry data of the electric analog quantity, the remote signaling data of the non-electric quantity state signal, and the protection action event are uploaded to the remote monitoring center through a communication protocol, and the protection setting value remote adjustment instruction of the monitoring center is received and executed.

[0037] Compared with the prior art, the application has the following advantages:

[0038] 1、The application overcomes the defects of traditional protection logic fragmentation and single information dimension by constructing a unified decision-making framework of electrical quantity protection and non-electrical quantity protection, fusing the electrical quantity information reflecting the operation state of the power grid and the non-electrical quantity information reflecting the state of the transformer body, realizing comprehensive and accurate identification of box transformer faults, and significantly improving the accuracy and reliability of protection decision-making.

[0039] 2、For the typical abnormal working condition of voltage transformer (TV) wire breakage, the application can reliably distinguish three-phase, single-phase and two-phase TV wire breakage through comprehensive analysis of phase voltage, line voltage and load current, and timely lock out related voltage protection functions, effectively avoiding protection misoperation or refusal caused by voltage sampling loop failure, and enhancing the selectivity and stability of the entire protection system.

[0040] 3、By introducing the soft pressure plate switching mechanism of non-electrical quantity protection, the operation personnel are given the ability to flexibly configure protection strategies (trip or alarm) according to actual working conditions, and at the same time, combined with the fault recording function, the key waveform data before and after the fault can be recorded completely, providing solid data support for post-fault tracing and accident analysis, and improving the flexibility and intelligent level of box transformer operation and maintenance. BRIEF DESCRIPTION OF DRAWINGS

[0041] In order to more clearly illustrate the technical solutions of the embodiments of the application, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the application, and for those skilled in the art, other drawings can be obtained without creative labor based on these drawings. Among them:

[0042] Figure 1 The overall flowchart of the integrated electrical quantity and non-electrical quantity monitoring box transformer comprehensive measurement and control protection method described for an embodiment of the application;

[0043] Figure 2 The A / D system principle schematic diagram of the integrated electrical quantity and non-electrical quantity monitoring box transformer comprehensive measurement and control protection method described for an embodiment of the application. DETAILED DESCRIPTION

[0044] In order to make the above-mentioned purposes, features and advantages of the application more apparent and easy to understand, the specific embodiments of the application will be described in detail below with reference to the drawings of the specification. Obviously, the described embodiments are part of the embodiments of the application, rather than all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor should be within the scope of protection of the application.

[0045] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. However, it will be apparent to one skilled in the art that the present application can be practiced without the specific details set forth in this description. In other instances, well-known methods, procedures, components, and circuits have not been described in detail so as not to unnecessarily obscure aspects of the present application.

[0046] It should also be noted that, as used in the specification and in the claims, the article "a", "an", or "the" is intended to mean that there is one or more of the features or elements. Unless otherwise indicated, the use of the terms "coupled" and / or "connected", and any variations thereof, are intended to mean either an indirect or direct connection in an electrical circuit. In addition, terms, such as first and second, third and fourth, etc., are used merely as labels, and are not intended to impose numerical requirements on their objects.

[0047] The present application is described in detail below with reference to the attached drawings.

[0048] In the description of the present application, it should be noted that the terms "upper and lower", "inner and outer", and the like indicate the positional or directional relationship shown in the drawings, and are merely for the purpose of facilitating the description of the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore should not be construed as limiting the present application. In addition, the terms "first", "second", or "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0049] Unless otherwise expressly specified and limited, the terms "mounting", "connection", "connection" in the present application should be understood broadly, for example: it can be fixed connection, detachable connection or integral connection; it can also be mechanical connection, electrical connection or direct connection, it can also be indirectly connected through intermediate medium, or it can be the internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0050] Embodiment 1

[0051] Reference Figure 1 and Figure 2 The first embodiment of the present application provides a box transformer integrated electrical and non-electrical quantity monitoring and control protection method, which comprises:

[0052] S1, collecting the multi-channel electrical analog quantity and non-electrical quantity state signals in the box transformer substation, comparing the collected electrical analog quantity with the preset electrical quantity protection setting value, and generating an electrical quantity protection judgment result according to the electrical quantity protection logic;

[0053] Specifically, through the AC plug-in of the NSC411U box transformer measurement and control protection device, the electrical analog quantity (signal) from the secondary side of the current transformer (CT) and the voltage transformer (PT) on the high-voltage side and the low-voltage side of the box-type substation is connected;

[0054] Further, with reference to Figure 2 The analog signals (such as three-phase currents Ia, Ib, Ic and three-phase voltages Ua, Ub, Uc) are sent into a low-pass filter through an AC conversion module (which includes an anti-interference filter link for filtering high-frequency interference and signal burrs introduced by the field environment); the cut-off frequency of the low-pass filter is set according to the sampling frequency (for example, half of the Nyquist frequency), and the core function of the low-pass filter is to prevent signal aliasing; then the analog signals modulated by the low-pass filter are forwarded to a high-speed and high-precision synchronous analog-to-digital (A / D) converter through a multiplexer (MUX), to obtain a digital signal stream; at this time, the analog-to-digital converter in the synchronous state ensures that all phase currents and voltages are sampled at exactly the same time, thereby accurately preserving the phase relationship between the electrical quantities; finally, the A / D converter samples at a frequency much higher than the power frequency (such as 64 points per cycle or higher), converts the continuous analog waveform into a discrete and high-fidelity digital sequence (composed of the original digital signal stream), and supplies the 32-bit high-performance microprocessor embedded in the NSC411U box transformer measurement and control protection device for real-time calculation and analysis;

[0055] It should be explained that the digital sequence after conversion preserves the original current and voltage waveform;

[0056] Further, the microprocessor continuously compares the specific values of the electrical quantities calculated in real time with the electrical quantity protection setting values (such as overcurrent setting value, overvoltage setting value, and undervoltage setting value) stored in the NSC411U box transformer measurement and control protection device in advance by the user or remotely;

[0057] It should be noted that the microprocessor does not directly use the original digital sequence for protection comparison, but performs real-time digital signal processing algorithm on the digital sequence to operate the latest waveform data collected in each sampling period;

[0058] Preferably, the microprocessor of the present application adopts Discrete Fourier Transform (DFT) to perform the digital signal processing algorithm;

[0059] Specifically, through the algorithm, the microprocessor can accurately calculate the core features of each electrical quantity from the sampling values, which include the following:

[0060] RMS (Root Mean Square): RMS of each phase current, RMS of each line (phase) voltage;

[0061] Phase angle: the angle of each electrical quantity relative to the reference phase;

[0062] Symmetrical component: positive sequence, negative sequence, zero sequence current and voltage;

[0063] Frequency: the real-time operating frequency of the power grid;

[0064] It should be noted that in actual application, the calculation of these characteristics is usually refreshed once every few milliseconds at a very high frequency, thereby providing continuous and dynamic electrical characteristic quantities for protection logic judgment;

[0065] In addition, it should be noted that the protection of the two power points of the high-voltage side and the low-voltage side is completely independent, and the NSC411U box transformer control protection device will perform the above processes from signal frequency modulation, A / D conversion, digital signal processing to protection logic judgment in parallel and independently for the electrical analog quantities collected from the high-voltage side and the low-voltage side;

[0066] Furthermore, the present application integrates multiple electrical quantity protection judgment methods, and the microprocessor can execute at least one of the following protection judgments according to the configuration:

[0067] For overcurrent protection judgment, a one-section time-limit overcurrent protection is taken as an example, and the detailed process is as follows: the microprocessor compares the effective value of any phase current calculated by the Fourier algorithm with the preset value of the user point by point (assuming that the effective value "1 side current I section" and the preset value "1 side current II section" are compared); once it is detected that the effective value of the phase current is greater than the preset value, the microprocessor immediately starts an internal software delay timer associated with the value and driven by the microprocessor clock; the delay timer starts from 0 and accumulates time, and if the count value of the timer reaches the preset value before the effective value of the phase current returns to below the value, the protection condition is confirmed to be met; at this time, it is determined that the overcurrent protection condition is met, and a protection judgment result flag bit is generated, which is set to "1" or "true"; if the current recovers during the timing process of the delay timer, the timer is reset to zero, and no judgment result that meets the condition is generated;

[0068] For low voltage protection judgment, which aims to prevent system voltage from being too low to cause damage to equipment or prematurely put the load in fault recovery, the microprocessor compares the effective value of the line voltage or phase voltage calculated in real time with the preset value of the user, and generates a judgment result that meets the condition when the following composite conditions are met:

[0069] Voltage out-of-limit condition: the effective value of at least one phase voltage is continuously lower than the preset value;

[0070] TV open circuit blocking condition: before this, the TV open circuit detection logic has not determined that the TV open circuit occurs;

[0071] Load current blocking condition (optional): in order to distinguish the normal low voltage of the no-load line from the abnormal low voltage when the load, a preset value can be configured, and only when the line current is less than the blocking current value, the low voltage protection is blocked;

[0072] Dynamic change rate blocking condition: in order to prevent the protection misoperation caused by the normal fluctuation of the system, the microprocessor also calculates the voltage change rate in real time; only when the absolute value of the voltage change rate is less than the preset voltage change rate threshold, it is considered that the voltage drop is in a stable state, and the low voltage protection logic is allowed to continue to execute;

[0073] Imbalance degree blocking condition: in order to ensure the response to the system low voltage under the condition of three-phase balance, the microprocessor calculates the negative sequence component of the voltage, and only when the negative sequence line voltage is less than a very small threshold (5V), the low voltage protection is started, so as to block the non-systematic voltage drop caused by the unbalanced fault such as single-phase grounding;

[0074] Delay condition: after the above conditions (i.e. voltage out-of-limit condition, TV open circuit blocking condition, load current blocking condition (optional), dynamic change rate blocking condition and imbalance degree blocking condition) are met, the delay timer associated with the preset value is started, and when the counting reaches the preset time length, it is finally determined that the low voltage protection condition is met;

[0075] In addition, the scheme of the application also executes the zero sequence overcurrent, overvoltage and overload protection judgment, which is similar to the overcurrent protection described above, that is, the judgment result is generated by comparing the real-time calculation value with the corresponding value and combining the delay timing, which will not be described here;

[0076] Further, in order to prevent the voltage protection misoperation or refusal caused by the abnormal voltage loop, the scheme of the application preferentially executes a TV open circuit detection step before performing the voltage related protection judgment:

[0077] When it is detected that the three-phase phase voltages are all lower than a preset first voltage threshold (8V), and at least one phase of the load current is greater than a preset current threshold (0.25A) at this time, it is determined that the three-phase TV open circuit occurs;

[0078] When the sum of the calculated three-phase voltages is greater than the first voltage threshold (excluding three-phase open circuit), but at the same time one of the following two conditions is met, it is determined that the single-phase or two-phase TV open circuit occurs:

[0079] When it is detected that the minimum line voltage is less than a preset second voltage threshold (16V), it is determined that the single-phase or two-phase TV open circuit occurs;

[0080] When the difference between the maximum line voltage and the minimum line voltage is greater than the second voltage threshold, it is also determined that single-phase or two-phase TV line breakage occurs;

[0081] Once any one of the TV line breakages is determined, all electrical quantity protection functions (such as overvoltage protection and low voltage protection) that are strongly dependent on voltage measurement are immediately automatically locked out, and a determination result of "TV line breakage" is generated;

[0082] Specifically, after the above operations are performed, one or more explicit electrical quantity protection determination results are output, such as "1-side overcurrent I-section condition is met", "TV line breakage occurs", or "electrical quantity is normal", etc.

[0083] S2, monitor the non-electrical quantity state signal, and generate a non-electrical quantity protection determination result according to the non-electrical quantity protection logic;

[0084] Further, the NSC411U box transformer control and protection device receives non-electrical quantity states (contacts) from the outside of the box transformer substation through its dedicated switch input terminal;

[0085] Specifically, the non-electrical quantity state signal includes switch signals of transformer heavy gas action, pressure relief valve action, low oil level, and high oil temperature;

[0086] In addition, in addition to the above switch signals, the non-electrical quantity state signal can also be an analog signal reflecting the state of the transformer, such as the main transformer oil temperature signal collected by a 4-20mA current loop or a PT100 platinum resistance. For such analog signals, the processing process is as follows:

[0087] For 4-20mA or PT100 analog signals, first, a dedicated conditioning circuit (such as precision resistance sampling and signal amplification) is used to convert it into a voltage signal matching the input range of the A / D converter, and then it is digitized by the A / D converter to obtain a digital value representing the real-time temperature. Then, the microprocessor compares the real-time temperature digital value with the temperature setting value (for example, 100℃) corresponding to the "high temperature delay time"; if the real-time temperature value continuously exceeds the temperature setting value and reaches the preset "high temperature delay time", the protection logic will query the soft pressure plate state corresponding to the "main transformer overtemperature" protection, if the pressure plate is put in, the determination result of "main transformer overtemperature trip" is generated; if the pressure plate is withdrawn, the determination result of "main transformer overtemperature alarm" is generated, and the determination result is stored for subsequent comprehensive decision-making;

[0088] It needs to be explained that, as the external non-electric quantity state (contact) signal is usually an active contact (such as AC220V), when the signal enters the NSC411U box transformer measurement and control protection device, it will first pass through the photoelectric isolation circuit to realize the safety isolation of the external strong current signal and the internal CPU weak current system, and effectively suppress interference;

[0089] Further, by continuously scanning the state of all switch quantity signal input terminals in the NSC411U box transformer measurement and control protection device in a high-frequency polling manner, when the level state of a certain terminal changes (for example, from low to high), the microprocessor can immediately identify the change and map it to a specific non-electric quantity event (for example, DI-05 port displacement corresponds to "main transformer heavy gas action") according to the pre-set terminal definition;

[0090] Further, after obtaining a specific non-electric quantity event, the same as the aforementioned micro-processing step, a protection action result is not immediately generated, but a non-electric quantity protection logic is first executed:

[0091] To prevent false alarms caused by sensor transient jitter or interference, when receiving any switch quantity signal in the non-electric quantity state signal, an independent delay timer corresponding to the signal type is started, and the delay time of the timer is determined by the user's pre-setting in the NSC411U box transformer measurement and control protection device. Value, such as "heavy gas delay time", "main transformer pressure release delay" and the like; During the delay timer timing or after the timing is over, the microprocessor queries the state of the protection on-off soft pad corresponding to the current non-electric quantity event by accessing the protection parameter configuration area stored in the non-volatile memory, to determine the final outlet behavior of the protection is tripping or only alarm, for example, for "main transformer heavy gas" protection, it will query whether its corresponding "main transformer heavy gas" pad is in "put in" or "exit" state;

[0092] Only when the non-electric quantity state signal lasts to the end of the pre-set delay time, will the final non-electric quantity protection judgment result be generated according to the queried soft pad state:

[0093] If the soft pad is in the "put in" state, it is determined that the non-electric quantity protection action condition is met, at this time, a protection action judgment result (for example, a "heavy gas protection tripping" event code is generated) will be generated, which will be an important basis for comprehensive decision-making, and will directly lead to the output of the tripping instruction;

[0094] If the soft pressure plate is in the "exit" state, only one alarm information is generated, at this time, although the non-electric quantity event is confirmed, the protection logic determines that it should not trigger the trip, but generate a lower level of "alarm" judgment result (for example, generate the event code of "heavy gas action alarm"), as described above, the judgment result will be an important basis for the comprehensive decision; and because the alarm signal output is triggered (such as lighting the panel alarm lamp, uploading the remote alarm information), the circuit breaker will not be actuated;

[0095] It should be noted that the soft pressure plate is a software control word or flag bit, which can be set by the user through the man-machine interface or remote communication;

[0096] S3, based on the electrical quantity protection judgment result and the non-electric quantity protection judgment result, making a comprehensive protection decision to determine whether the preset protection action condition is met;

[0097] Further, an event arbitration logic is constructed in the microprocessor of the NSC411U box transformer control protection device, which continuously and real-timely receives and evaluates the electrical quantity protection judgment result generated in step S1 and the non-electric quantity protection judgment result generated by step S2;

[0098] It should be noted that the core decision mechanism of the event arbitration logic is a decision matrix based on event priority, which pre-defines the response level (for example, "trip level", "alarm level" or "normal level") of all possible protection judgment results generated by steps S1 and S2, and its decision process follows the following principles:

[0099] The highest priority processing (trip level event): first, the event arbitration logic checks all the input judgment results; if any of the electrical quantity protection judgment results points to a trip, for example, step S1 determines that the "1 side current I section" or "1 side current II section" protection condition is met (i.e. current overrun and delay arrives), then this result is regarded as a valid "trip" request, i.e. electrical quantity trip event; or, if any of the non-electric quantity protection judgment results contains a trip event confirmed by the soft pressure plate in the "on" state, for example, step S2 determines that the "main transformer heavy gas action" and its corresponding soft pressure plate is in the "on" state, thereby generating the judgment result of "heavy gas protection trip", then this result is also regarded as a valid "trip" request, i.e. non-electric quantity trip event; once at least one trip event is detected, the event arbitration logic no longer evaluates other low-priority alarm information, directly determines the comprehensive decision result as "meeting the preset protection action condition", and generates a final action instruction code carrying the highest priority trip reason (such as "1 side overcurrent I section" or "main transformer heavy gas");

[0100] Secondary priority processing (alarm level event): if no trip level event is detected in the current processing cycle, the event arbitration logic continues to scan whether there is an event defined as an alarm level; for example, step S1 determines that a "TV line break" occurs, and generates a "TV line break alarm" determination result, which is an electrical quantity alarm event; or, step S2 determines that a "main transformer oil level low" occurs, but its corresponding soft pressure plate is in the "exit" state, thereby generating a "main transformer oil level low alarm" determination result, which is a non-electrical quantity alarm event; if the above alarm event is detected, the comprehensive decision result is "not to meet the protection action condition" (i.e. not to trip), but one or more corresponding alarm instruction codes are generated to drive the panel light, buzzer or upload remote alarm information;

[0101] Default state (normal level): if all inputs are scanned and no "trip level" or "alarm level" event is found, the comprehensive decision result is "not to meet the protection action condition", and the device maintains a normal monitoring state;

[0102] It should be noted that by constructing a comprehensive protection decision, any serious fault reaching the trip level (whether electrical or physical) can be responded to without discrimination and with the highest priority;

[0103] S4, when the comprehensive protection decision meets the preset protection action condition, output control instructions are driven to drive the associated circuit breaker to act;

[0104] Further, when the microprocessor in the NSC411U box transformer control and protection device receives the final action instruction code carrying the trip reason issued by the event arbitration logic of step S3, the export processing program is immediately started, and the core task of the program is to map the logical instruction to the physical export;

[0105] Further, the microprocessor queries the internal preset export matrix configuration table according to the received action instruction code (for example, "1 side overcurrent I section trip" or "main transformer heavy gas trip"), which defines the mapping relationship between each protection event and one or more physical export relays (DO), allowing users to flexibly configure which fault triggers the trip of which circuit breaker; after locating the target export relay, the microprocessor sends a high-level signal to the driving circuit of the relay through its I / O port, and the driving circuit uses the 24V DC power provided by the internal power supply plug-in of the device, which is isolated from the microprocessor, to energize the coil of the target export relay; after the coil is energized, the armature moves, causing the normally open contact (NO) of the relay to momentarily close, wherein the closing action of the contact is also the physical entity of the output control instruction in the present application;

[0106] Specifically, for the closed outlet relay contact, its two ends are connected with the trip coil loop of the associated circuit breaker in the box-type substation outside the device. When the contact is closed, the loop is turned on, so that a strong operating current (in the range of 0.5A to 4A) flows through the trip coil of the circuit breaker; the trip coil is energized by the strong current to generate sufficient electromagnetic force, thereby driving the trip mechanism of the circuit breaker and releasing its mechanical lock. At this time, the circuit breaker can be quickly tripped under the action of the energy storage spring, thereby cutting off the fault current in milliseconds (the inherent action time of the quick-acting section is less than 40ms), isolating the fault point, and protecting the safety of the transformer and related power equipment;

[0107] Further, after outputting the control instruction to drive the circuit breaker to act, the microprocessor triggers the following tasks in parallel to ensure the integrity and traceability of the fault information:

[0108] The first task: the microprocessor immediately generates a structured event record of the fault event information (including fault type, action time accurate to milliseconds, electrical quantity value at the time of fault, and action protection element) triggered by the current control instruction, and stores it in the non-volatile memory for query; at the same time, the NSC411U box-type substation measurement and control protection device immediately locks the running ring buffer area in its internal RAM, which stores real-time high-speed sampling waveform data of all key electrical analog quantities (such as Ia, Ib, Ic, Ua, Ub, Uc); the microprocessor extracts the complete waveform data segment before and after the fault occurrence from the buffer area according to the preset recording strategy (for example, “4 cycles before fault, 6 cycles after fault”), forms a fault recording file, and stores the fault recording file in the non-volatile memory as well.

[0109] The second task: push the circuit breaker action to the communication processing module of the NSC411U box-type substation measurement and control protection device. The module encapsulates the current protection action event into a remote signaling change (SOE) message through a preset communication protocol (such as IEC-103 / 104 or Modbus), and actively uploads it to the remote monitoring center or background master station through the RS485 or Ethernet interface, so that the operation personnel can know the fault tripping information of the box-type substation in the first time, thereby realizing the “remote signaling” function in the “four remote” function and improving the flexibility and intelligent level of box-type substation operation and maintenance.

[0110] Those skilled in the art will appreciate that embodiments of the present application can be readily used as software, hardware, or a combination of software and hardware. In a software embodiment, various elements are implemented in hardware, software, or a combination of both hardware and software. In a software embodiment, the software implementation can be

[0111] The computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks. Figure 1 one or more flowcharts and / or blocks Figure 1 means for functionally implementing the steps listed in the flowchart block or blocks.

[0112] These computer program instructions can also be stored in a computer- readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instructions which implement the function specified in the flowchart block or blocks. Figure 1 one or more flowcharts and / or blocks Figure 1 means for functionally implementing the steps listed in the flowchart block or blocks.

[0113] The computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks. Figure 1 one or more flowcharts and / or blocks Figure 1 means for functionally implementing the steps listed in the flowchart block or blocks.

[0114] While the preferred embodiments of the application have been described, additional variations and modifications can be employed. Therefore, the terms and expressions

[0115] Obviously, numerous modifications and variations of the present application are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims and their equivalents, the application can be practiced otherwise than as specifically described.

Claims

1. A method for integrated electrical quantity and non-electrical quantity monitoring of a box transformer comprehensive measurement and control protection, characterized in that, The method comprises: collecting multiple electrical analog and non-electrical quantity state signals in a box-type substation, comparing the collected electrical analog quantity with preset electrical quantity protection setting values, and generating electrical quantity protection judgment results according to electrical quantity protection logic; a TV line break detection step, which is performed after the multiple electrical analog and non-electrical quantity state signals in the box-type substation, comprises: when it is detected that the three-phase phase voltages are all lower than a preset first voltage threshold value and at least any one phase current is greater than a preset current threshold value, it is determined as three-phase TV line break; when it is detected that the sum of the three-phase voltages is greater than the first voltage threshold value and the minimum line voltage is less than a preset second voltage threshold value, it is determined as single-phase or two-phase TV line break; when it is detected that the sum of the three-phase voltages is greater than the first voltage threshold value and the difference between the maximum line voltage and the minimum line voltage is greater than the second voltage threshold value, it is determined as single-phase or two-phase TV line break; after determining the three-phase TV line break, the single-phase or two-phase TV line break, automatically locking all electrical quantity protection functions dependent on voltage measurement; monitoring the non-electrical quantity state signals and generating non-electrical quantity protection judgment results according to non-electrical quantity protection logic; based on the electrical quantity protection judgment results and the non-electrical quantity protection judgment results, making comprehensive protection decisions to determine whether the preset protection action condition is met; when the comprehensive protection decision meets the preset protection action condition, outputting a control instruction to drive the associated circuit breaker to act.

2. The integrated electrical and non-electrical quantity monitoring method of the transformer substation comprehensive measurement and control protection according to claim 1, characterized in that, The multiple electrical analog and non-electrical quantity state signals in the box-type substation comprise: simultaneously collecting electrical analog quantities of two power points on the high-voltage side and the low-voltage side of the box-type substation, and independently performing the two power points, comparing the collected electrical analog quantities with preset electrical quantity protection setting values, and generating electrical quantity protection judgment results according to electrical quantity protection logic.

3. The integrated electrical and non-electrical quantity monitoring method of the transformer substation comprehensive measurement and control protection according to claim 1, characterized in that, The electrical analog quantity includes three-phase current and three-phase voltage; the non-electrical quantity state signal is represented as a signal reflecting the state of the transformer body, and the signal is at least one of a switching quantity signal and an analog signal.

4. The integrated electrical and non-electrical quantity monitoring method of the transformer substation comprehensive measurement and control protection of claim 2, wherein, The generation of the electrical quantity protection judgment result according to the electrical quantity protection logic comprises: the execution process of at least one protection judgment mode selected from the following: overcurrent protection judgment, zero sequence overcurrent protection judgment, overvoltage protection judgment, low voltage protection judgment and overload protection judgment.

5. The integrated electrical and non-electrical quantity monitoring method of the transformer substation comprehensive measurement and control protection according to claim 4, characterized in that, The overcurrent protection judgment comprises: comparing the calculated value of any one phase current in the three-phase current with at least one preset overcurrent setting value; if the phase current calculated value is continuously greater than the overcurrent setting value, start the delay timing; when the delay timing reaches the preset time setting value corresponding to the overcurrent setting value, it is determined that the overcurrent protection condition is met.

6. The integrated electrical and non-electrical quantity monitoring method of the transformer substation comprehensive measurement and control protection according to claim 1, characterized in that, The non-electrical quantity state signal comprises at least one switching quantity signal selected from transformer heavy gas, pressure release, low oil level and high oil temperature.

7. The integrated electrical and non-electrical quantity monitoring method of the transformer substation comprehensive measurement and control protection according to claim 6, characterized in that, The non-electrical quantity protection logic comprises: after receiving the non-electrical quantity state signal, querying the protection on-off soft pad state corresponding to the signal; If the soft pressure plate is in the input state, it is determined that the non-electric quantity protection action condition is met, and if the soft pressure plate is in the exit state, alarm information is generated.

8. The integrated electrical and non-electrical quantity monitoring method of the transformer substation comprehensive measurement and control protection of claim 1, wherein, Further comprising: Recording fault event information triggering the control instruction; All electrical analog quantity waveform data of a preset time length before the fault occurrence time and the preset time length after the fault occurrence time are intercepted and stored in the non-volatile memory.

9. The integrated electrical and non-electrical quantity monitoring method of the transformer substation comprehensive measurement and control protection of claim 1, wherein, Further comprising a remote interaction step: real-time telemetry data of the electrical analog quantity, remote signaling data of the non-electric quantity state signal, and protection action events are uploaded to a remote monitoring center through a communication protocol, and protection setting value remote adjustment instructions of the monitoring center are received and executed.

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