Box transformer substation comprehensive measurement and control protection method integrating electrical quantity and non-electrical quantity monitoring

Abstract

The invention discloses a box transformer comprehensive measurement and control protection method integrating electrical quantity and non-electrical quantity monitoring, and the method comprises the steps: collecting the electrical analog quantity of a box transformer, carrying out the discrimination based on a preset electrical quantity protection logic, and generating an electrical quantity protection judgment result; non-electric quantity state signals reflecting the state of the transformer body are collected, judgment is carried out based on preset non-electric quantity protection logic, and a non-electric quantity protection judgment result is generated; according to the electric quantity protection judgment result and the non-electric quantity protection judgment result, comprehensive protection decision making is carried out through collaborative decision logic, and whether a preset protection action condition is met or not is determined; when the comprehensive protection decision result is that the protection action condition is met, a control instruction is output to drive an associated circuit breaker to act; the electrical quantity information and the non-electrical quantity information are placed under the unified collaborative decision framework, comprehensive and rapid response to the box transformer substation fault is achieved, the protection reliability and accuracy are effectively improved, and misoperation or operation refusal possibly caused by a single information source is avoided.

Description

Technical Field

[0001] This invention relates to the field of power system relay protection technology, and in particular to a comprehensive measurement and control protection method for prefabricated substations that integrates the monitoring of electrical and non-electrical quantities. Background Technology

[0002] With the rapid development of distributed energy sources such as wind power and photovoltaic power generation, prefabricated substations, as key hubs connecting new energy power generation units and the power grid, are crucial for safe and stable operation. To meet the high demands of modern power grids for automation and reliability, the measurement and protection technology for prefabricated substations has gradually evolved from traditional single relay protection to integrated, intelligent microprocessor-based protection devices. These devices generally employ embedded microprocessor technology, enabling real-time monitoring of electrical quantities (such as current and voltage) within the substation and performing conventional electrical quantity protection such as overcurrent and overvoltage. Simultaneously, they achieve remote data transmission and control through communication interfaces, adapting to the "less-manned" operation mode of the substation.

[0003] However, existing technologies still have shortcomings in achieving comprehensive protection for prefabricated substations. First, the monitoring and protection logic for electrical and non-electrical quantities (such as transformer oil temperature, oil level, and gas pressure) is often fragmented. Non-electrical quantity protection typically functions as independent alarm or trip inputs, lacking deep integration and collaborative decision-making mechanisms with electrical quantity protection logic. This results in limited comprehensive fault judgment capabilities of the protection system, and the information dimension is singular, making it difficult to accurately and quickly diagnose the intrinsic correlation between electrical anomalies and changes in the physical state of equipment. Second, some existing protection schemes are not precise or robust enough in identifying abnormal operating conditions. For example, when a voltage transformer (TV) secondary circuit breaks, if the detection logic is incomplete, it can easily cause voltage-dependent protection functions (such as undervoltage and overvoltage protection) to malfunction or fail to operate, posing a threat to system safety.

[0004] CN104836340A discloses an intelligent monitoring system and method for monitoring the operation of prefabricated substations. This solution combines smart grid technology and internet technology in the prefabricated substation, achieving self-identification, self-diagnosis, self-monitoring, and self-action of the prefabricated substation through the introduction of compatible intelligent monitoring devices, reliable communication methods, and comprehensive communication protocols. However, this solution primarily relies on communication networking to monitor the operation of the prefabricated substation and does not mention the decision-making mechanism for electrical quantity protection and non-electrical quantity protection.

[0005] CN112993936B discloses an integrated protection method, system, terminal, and storage medium for prefabricated substations. This scheme calculates the sudden changes in starting current of the low-voltage outgoing lines and the sudden changes in current on the high-voltage side of the transformer to provide disconnection protection for the low-voltage outgoing lines, the transformer, and the low-voltage busbar. Furthermore, based on the amplitude of the transformer's low-voltage side current and the total amplitude of the currents from all low-voltage outgoing lines, it determines whether to implement delayed disconnection protection for the transformer and the low-voltage busbar. While the scheme mentions protection measures for electrical quantities, it primarily extends multi-level protection to the very end of the power system to improve power supply reliability, but it lacks consideration for the protection of non-electrical quantities.

[0006] Therefore, there is an urgent need for a comprehensive protection method that can integrate electrical and non-electrical quantity information, possess a unified collaborative decision-making logic, and have a high reliability in identifying key abnormal operating conditions. Summary of the Invention

[0007] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0008] In view of the aforementioned existing problems, this invention is proposed. Therefore, this invention provides a comprehensive measurement, control, and protection method for prefabricated substations that integrates electrical and non-electrical quantity monitoring, to solve the problems mentioned in the background art.

[0009] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a comprehensive measurement, control, and protection method for prefabricated substations that integrates electrical and non-electrical quantity monitoring, comprising: Collect multiple electrical analog and non-electrical status signals in the prefabricated substation, compare the collected electrical analog quantities with preset electrical protection settings, and generate electrical protection judgment results based on electrical protection logic; Monitor the non-electrical quantity status signal and generate a non-electrical quantity protection judgment result based on the non-electrical quantity protection logic; Based on the judgment results of the electrical quantity protection and the judgment results of the non-electrical quantity protection, a comprehensive protection decision is made to determine whether the preset protection action conditions are met. When the integrated protection decision meets the preset protection action conditions, a control command is output to drive the associated circuit breaker to operate.

[0010] As a preferred embodiment of the integrated electrical and non-electrical quantity monitoring method for prefabricated substations described in this invention, the method for acquiring multiple electrical analog and non-electrical quantity status signals within the prefabricated substation includes: Simultaneously, the electrical analog quantities of two power points on the high-voltage side and low-voltage side of the prefabricated substation are collected, and the two power points are executed independently. The collected electrical analog quantities are compared with the preset electrical quantity protection settings, and the electrical quantity protection judgment result is generated according to the electrical quantity protection logic.

[0011] As a preferred embodiment of the integrated monitoring and control protection method for transformer substations that integrates electrical and non-electrical quantities as described in this invention, the electrical analog quantities include three-phase current and three-phase voltage; the non-electrical quantity status signals are signals reflecting the status of the transformer itself, and the signals are at least one of switching signals and analog signals.

[0012] As a preferred embodiment of the integrated electrical and non-electrical quantity monitoring method for transformer substations described in this invention, wherein: the step of generating electrical quantity protection judgment results based on electrical quantity protection logic includes: Its execution process includes at least one of the following protection judgment methods: overcurrent protection judgment, zero-sequence overcurrent protection judgment, overvoltage protection judgment, undervoltage protection judgment, and overload protection judgment.

[0013] As a preferred embodiment of the integrated electrical and non-electrical quantity monitoring method for transformer substations described in this invention, the overcurrent protection judgment includes: The calculated value of any phase current among the collected three-phase currents is compared with at least one preset overcurrent setting. If the calculated phase current value continues to be greater than the overcurrent setting value, then the delay timer is started; When the delay time reaches the preset time value corresponding to the overcurrent set value, it is determined that the overcurrent protection condition is met.

[0014] As a preferred embodiment of the integrated electrical and non-electrical quantity monitoring method for transformer substations described in this invention, the non-electrical quantity status signal includes at least one switching signal selected from transformer heavy gas, pressure release, low oil level, and high oil temperature.

[0015] As a preferred embodiment of the integrated electrical and non-electrical quantity monitoring method for transformer substations described in this invention, the non-electrical quantity protection logic includes: Upon receiving the non-electrical quantity status signal, query the status of the protection activation / deactivation soft switch corresponding to the signal; If the soft pressure plate is in the engaged state, the non-electrical protection action condition is met; if the soft pressure plate is in the disengaged state, an alarm message is generated.

[0016] As a preferred embodiment of the integrated electrical and non-electrical quantity monitoring method for transformer substations described in this invention, after outputting control commands to drive the associated circuit breaker to operate, the method further includes: Record fault event information that triggers the control command; All electrical analog waveform data for a preset duration before and after the fault occurrence are extracted and stored in non-volatile memory.

[0017] As a preferred embodiment of the integrated electrical and non-electrical quantity monitoring method for prefabricated substations described in this invention, it further includes a TV disconnection detection step, which is performed after acquiring multiple electrical analog and non-electrical quantity status signals within the prefabricated substation, including: When it is detected that the three-phase phase voltages are all lower than the preset first voltage threshold and at least one phase current is greater than the preset current threshold, it is determined that the three-phase TV is disconnected. When the sum of the three-phase voltages is detected to be greater than the first voltage threshold and the minimum line voltage is less than the preset second voltage threshold, it is determined to be a single-phase or two-phase TV disconnection. When the sum of the three-phase voltages is detected to be 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 to be a single-phase or two-phase TV disconnection. Upon determining that a three-phase TV circuit is open, a single-phase TV circuit is open, or a two-phase TV circuit is open, all electrical quantity protection functions that rely on voltage measurement are automatically locked.

[0018] As a preferred embodiment of the integrated electrical and non-electrical quantity monitoring method for transformer substations described in this invention, it further includes a remote interaction step: The real-time telemetry data of the electrical analog quantities, the remote signaling data of the non-electrical quantity status signals, and the protection action events are uploaded to the remote monitoring center through a communication protocol, and the monitoring center's protection setting remote adjustment commands are received and executed.

[0019] Compared with existing technologies, the beneficial effects of the invention are: 1. This invention constructs a unified decision-making framework for electrical quantity protection and non-electrical quantity protection, and integrates electrical quantity information reflecting the power grid operation status with non-electrical quantity information reflecting the transformer's physical status for judgment. This overcomes the shortcomings of traditional protection logic being fragmented and having a single information dimension, and achieves comprehensive and accurate identification of transformer faults, significantly improving the accuracy and reliability of protection decisions. 2. In response to the typical abnormal operating condition of voltage transformer (TV) disconnection, this invention can reliably distinguish between three-phase, single-phase and two-phase TV disconnection through comprehensive analysis of phase voltage, line voltage and load current, and promptly lock out the relevant voltage protection functions, effectively avoiding protection maloperation or failure to operate due to voltage sampling circuit failure, and enhancing the selectivity and stability of the entire protection system. 3. By introducing a soft-plate activation / deactivation mechanism for non-electrical protection, operators are empowered to flexibly configure protection strategies (tripping or alarm) according to actual operating conditions. At the same time, combined with the fault recording function, key waveform data before and after a fault can be recorded completely, providing solid data support for post-fault tracing and accident analysis, and improving the flexibility and intelligence level of transformer substation operation and maintenance. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein: Figure 1 This is a flowchart illustrating the overall process of a comprehensive measurement, control, and protection method for prefabricated substations that integrates electrical and non-electrical quantity monitoring, as described in one embodiment of the present invention. Figure 2 This is a schematic diagram of the A / D system principle of the integrated electrical and non-electrical quantity monitoring and control protection method for transformer substations according to an embodiment of the present invention. Detailed Implementation

[0021] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0022] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0023] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0024] This invention is described in detail with reference to the schematic diagrams. When detailing the embodiments of this invention, for ease of explanation, the cross-sectional views illustrating the device structure may be partially enlarged, not adhering to the usual scale. Furthermore, the schematic diagrams are merely examples and should not be construed as limiting the scope of protection of this invention. In actual fabrication, the three-dimensional spatial dimensions of length, width, and depth should be included.

[0025] Furthermore, in the description of this invention, it should be noted that the terms "upper," "lower," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are used solely for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. 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.

[0026] Unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" in this invention should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; similarly, they can refer to mechanical connections, electrical connections, or direct connections, or indirect connections through an intermediate medium, or internal connections between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0027] Example 1 Reference Figure 1 and Figure 2 This is the first embodiment of the present invention, which provides a comprehensive measurement, control, and protection method for prefabricated substations that integrates electrical and non-electrical quantity monitoring, including: S1. Collect multiple electrical analog and non-electrical status signals in the box-type substation, compare the collected electrical analog quantities with the preset electrical quantity protection settings, and generate electrical quantity protection judgment results according to the electrical quantity protection logic. Specifically, through the AC plug-in inside the NSC411U box-type substation monitoring and protection device, electrical analog quantities (signals) from the secondary side of the current transformer (CT) and voltage transformer (PT) on the high-voltage and low-voltage sides of the box-type substation are connected. For further reference, Figure 2These analog signals (such as three-phase currents Ia, Ib, Ic and three-phase voltages Ua, Ub, Uc) are passed through an AC converter module (this circuit includes an anti-interference filter to filter out high-frequency interference and signal glitches introduced by the field environment) and sent to a low-pass filter. The cutoff frequency of the low-pass filter is set according to the sampling frequency (for example, set to half of the Nyquist frequency). The core function of this low-pass filter is to prevent signal aliasing. Then, the analog signal modulated by the low-pass filter is forwarded to a high-speed, high-precision synchronous analog-to-digital converter (MUX) through a multiplexer. In the A / D converter, a digital signal stream is obtained. At this time, the analog-to-digital converter in synchronous state ensures that the current and voltage signals of all phases are sampled at exactly the same time, thus accurately preserving the phase relationship between various electrical quantities. Finally, through this A / D converter, and by sampling at a frequency much higher than the power frequency (such as 64 points or higher per cycle), the continuous analog waveform is converted into a discrete, high-fidelity digital sequence (composed of the original digital signal stream) for real-time calculation and analysis by the 32-bit high-performance microprocessor embedded in the NSC411U transformer substation measurement and control protection device. It should be explained that the original current and voltage waveforms are preserved in the converted digital sequence; Furthermore, the microprocessor will collect and calculate the specific values ​​of electrical quantities in real time and continuously compare them with the electrical quantity protection settings (such as overcurrent settings, overvoltage settings, undervoltage settings, etc.) that the user or remote communication has stored in the NSC411U transformer substation measurement and control protection device in advance. It should be noted that the microprocessor does not directly use the original digital sequence for protection comparison, but instead performs real-time digital signal processing algorithms on the digital sequence to process the latest waveform data acquired in each sampling period. Preferably, the microprocessor of the present invention uses Discrete Fourier Transform (DFT) to execute digital signal processing algorithms; Specifically, through this algorithm, the microprocessor can accurately calculate the core characteristics of each electrical quantity from the sampled values. These core characteristics include the following: Effective values ​​(RMS): Effective values ​​of current in each phase and effective values ​​of voltage in each line (phase); Phase angle: The angle of each electrical quantity relative to a reference phase; Symmetrical components: positive-sequence, negative-sequence, and zero-sequence currents and voltages; Frequency: The real-time operating frequency of the power grid; It should be noted that in practical applications, the calculation of these features is usually refreshed at an extremely high frequency (e.g., every few milliseconds), thus providing continuous and dynamic electrical characteristic quantities for protection logic judgment. Furthermore, it should be noted that the protection of the two power points on the high-voltage side and the low-voltage side in this invention is carried out completely independently. For the electrical analog quantities collected from the high-voltage side and the low-voltage side respectively, the NSC411U transformer substation monitoring and protection device will execute the entire process from signal frequency modulation, A / D conversion, digital signal processing to protection logic judgment in parallel and independently. Furthermore, the present invention integrates multiple electrical quantity protection judgment methods, and the microprocessor can execute at least one of the following protection judgments according to the configuration: For overcurrent protection judgment, taking a single-stage time-limit overcurrent protection as an example, the detailed judgment process is as follows: The microprocessor calculates the effective value of any phase current using the Fourier algorithm and compares this effective value with the user-preset value point by point (assuming the effective value "current segment I on side 1" is compared with the preset value "current segment II on side 1"). Once the effective value of the phase current is detected to be greater than the preset value, the microprocessor immediately starts an internal software delay timer associated with the preset value and driven by the microprocessor clock. The delay timer starts accumulating time from 0. If the count value of the timer reaches the preset value before the effective value of the phase current recovers below the preset 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 is generated and set to "1" or "true". If the current recovers during the timing of the delay timer, the timer is reset to zero, and no judgment result is generated indicating that the condition is met. For undervoltage protection judgment, the aim is to prevent damage to equipment due to excessively low system voltage or premature load energization during fault recovery. The microprocessor compares the real-time calculated effective values ​​of line voltage or phase voltage with user-preset values. A judgment result is generated only when the following combined conditions are met: Voltage over-limit condition: The effective value of at least one phase voltage is continuously lower than the preset value; TV disconnection interlocking condition: Prior to this, the TV disconnection detection logic has not determined that a TV disconnection has occurred; Load current blocking condition (optional): To distinguish between normal low voltage of unloaded lines and abnormal low voltage under load, a preset value can be configured. The low voltage protection will only be blocked when the line current is less than the blocking current setting value. Dynamic rate of change blocking condition: To prevent protection maloperation caused by normal system fluctuations, the microprocessor will also calculate the voltage rate of change in real time; only when the absolute value of the voltage rate of change is less than the preset voltage rate of change threshold is the voltage drop considered to be a stable state, and the low voltage protection logic is allowed to continue to execute. Unbalance blocking condition: In order to ensure the response to systemic low voltage under the condition of three-phase basic balance, the microprocessor calculates the negative sequence component of the voltage and only activates the low voltage protection when the negative sequence line voltage is less than a very small threshold (5V), thereby blocking the non-systemic voltage drop caused by unbalance faults such as single-phase grounding. Delay conditions: After all the above conditions (i.e., voltage over-limit condition, TV disconnection lockout condition, load current lockout condition (optional), dynamic change rate lockout condition, and unbalance lockout condition) are met, the delay timer associated with the preset value is started. When the timer reaches the preset duration, it is finally determined that the undervoltage protection condition is met. In addition, the present invention will also perform judgments on zero-sequence overcurrent, overvoltage and overload protection. The implementation method is similar to the above-mentioned overcurrent protection, that is, by comparing the real-time calculated value with the corresponding set value and combining the delay time to generate the judgment result, which will not be described in detail here. Furthermore, to prevent voltage circuit abnormalities from causing false tripping or failure to trip of voltage protection, the present invention performs a TV disconnection detection step before performing voltage-related protection judgments: When it is detected that the phase voltage of all three phases is lower than a preset first voltage threshold (8V), and at this time the load current of at least one phase is greater than a preset current threshold (0.25A), it is determined that the three-phase TV is disconnected. If the sum of the calculated three-phase voltages is greater than the first voltage threshold (excluding three-phase open circuits), but one of the following two conditions is met, it is determined to be a single-phase or two-phase TV open circuit: When the minimum line voltage is detected to be less than a preset second voltage threshold (16V), it is determined to be a single-phase or two-phase TV disconnection. When the difference between the maximum line voltage and the minimum line voltage is detected to be greater than the second voltage threshold, it is also determined to be a single-phase or two-phase TV disconnection. Once any TV disconnection is detected, all electrical quantity protection functions that heavily rely on voltage measurement (such as overvoltage protection and undervoltage protection) will be automatically locked immediately, and a "TV disconnection" judgment result will be generated. Specifically, after performing the above operations, one or more clear electrical quantity protection judgment results are output, such as "Overcurrent I-stage condition on side 1 is met", "TV disconnection has occurred", or "Electrical quantity is normal", etc. S2. Monitor non-electrical quantity status signals and generate non-electrical quantity protection judgment results based on non-electrical quantity protection logic; Furthermore, the NSC411U prefabricated substation monitoring and protection device receives non-electrical status (contact) signals from outside the prefabricated substation through its dedicated digital input terminals; Specifically, the non-electrical status signals include switching signals for transformer heavy gas activation, pressure relief valve activation, low oil level, and excessively high oil temperature. In addition to the aforementioned switching signals, this non-electrical status signal can also be an analog signal reflecting the transformer's status, such as the main transformer oil temperature signal acquired through a 4-20mA current loop or a PT100 platinum resistance thermometer. The processing procedure for this type of analog signal is as follows: For 4-20mA or PT100 analog signals, a dedicated conditioning circuit (such as precision resistor sampling and signal amplification) is first used to convert them into voltage signals that match the input range of the A / D converter. Then, the A / D converter digitizes these signals to obtain a digital value representing the real-time temperature. Next, a microprocessor compares this real-time temperature value with a preset temperature setpoint (e.g., 100℃) corresponding to an "over-temperature delay time." If the real-time temperature value continuously exceeds this setpoint and reaches the preset "over-temperature delay time," the protection logic queries the status of the soft switch corresponding to the "main transformer over-temperature" protection. If the switch is engaged, a "main transformer over-temperature trip" judgment result is generated; if the switch is disengaged, a "main transformer over-temperature alarm" judgment result is generated. This judgment result is stored for subsequent comprehensive decision-making. It should be explained that since the external non-electrical quantity status (contact) signal is usually an active contact (such as AC220V), when the signal enters the NSC411U transformer substation monitoring and protection device, it will first pass through the opto-isolation circuit to achieve safe isolation between the external high-voltage signal and the internal CPU low-voltage system, while effectively suppressing interference. Furthermore, by continuously scanning the status of all digital input terminals with high-frequency polling by the microprocessor in the NSC411U transformer substation monitoring and protection device, when the level of a terminal changes (for example, from low level to high level), the microprocessor can immediately identify the change and map it to a specific non-electrical event according to the preset terminal definition (for example, the change of the DI-05 port corresponds to "main transformer heavy gas operation"). Furthermore, upon receiving a specific non-electrical event, similar to the aforementioned microprocessing steps, a protection action result is not immediately generated; instead, the non-electrical protection logic is executed first. To prevent false alarms caused by momentary sensor jitter or interference, upon receiving any switching signal among the non-electrical quantity status signals, an independent delay timer corresponding to that signal type is activated. The delay duration of this timer is determined by a preset value set by the user in the NSC411U transformer substation monitoring and protection device, such as "heavy gas delay time" or "main transformer pressure release delay." During or after the delay timer's timing, the microprocessor accesses the protection parameter configuration area stored in non-volatile memory to query the status of the protection enable / disable soft switch corresponding to the current non-electrical quantity event, in order to determine whether the final output behavior of the protection is tripping or only alarming. For example, for "main transformer heavy gas" protection, it will query whether its corresponding "main transformer heavy gas" switch is in an "enabled" or "disabled" state. Only after the non-electrical quantity status signal continues for the preset delay time will the final non-electrical quantity protection judgment result be generated based on the queried soft pressure plate status. If the soft pressure plate is in the "engaged" state, it is determined that the non-electrical protection action conditions are met. At this time, a protection action judgment result will be generated (for example, an event code for "heavy gas protection trip" will be generated). This judgment result will serve as an important basis for comprehensive decision-making and will directly lead to the output of the trip command. If the soft pressure plate is in the "exit" state, only one alarm message will be generated. At this time, although the non-electrical event is confirmed, the protection logic determines that it should not trigger a trip, but instead generates a lower-level "alarm" judgment result (for example, generating an event code for "heavy gas operation alarm"). As mentioned above, this judgment result will be used as an important basis for comprehensive decision-making. Furthermore, because what is triggered is the output of an alarm signal (such as lighting up the panel alarm light or uploading remote alarm information), it will not cause the circuit breaker to operate. It should be noted that the soft pressure plate is a software control word or flag bit, which can be adjusted by the user through the human-machine interface or remote communication; S3. Based on the judgment results of electrical quantity protection and non-electrical quantity protection, make a comprehensive protection decision to determine whether the preset protection action conditions are met; Furthermore, an event arbitration logic is built inside the microprocessor of the NSC411U transformer substation measurement and control protection device. This event arbitration logic continuously and in real time receives and evaluates the electrical quantity protection judgment result generated in step S1 and the non-electrical quantity protection judgment result generated in step S2. It should be noted that the core decision-making mechanism of this event arbitration logic is a decision matrix based on event priority. This matrix predefines the response level (e.g., "tripping level", "alarm level", or "normal level") of all possible protection judgment results generated by steps S1 and S2. Its decision-making process follows the following principles: Highest priority processing (tripping-level events): First, the event arbitration logic checks the judgment results of all inputs. If the electrical quantity protection judgment result contains any event pointing to tripping, for example, if step S1 determines that the protection conditions of "current stage I on side 1" or "current stage II on side 1" are met (i.e., the current exceeds the limit and arrives after a delay), then the result is considered a valid "tripping" request, i.e., an electrical quantity tripping event. Alternatively, if the non-electrical quantity protection judgment result contains any tripping event confirmed by a soft pressure plate in the "on" state, for example, if step S2 determines that "main transformer heavy gas operation" and its corresponding soft pressure plate is in the "on" state, thus generating a judgment result of "heavy gas protection tripping", then the result is also considered a valid "tripping" request, i.e., a non-electrical quantity tripping event. Once at least one tripping event is detected, the event arbitration logic no longer evaluates other low-priority alarm information, directly determines the comprehensive decision result as "meets the preset protection operation conditions", and generates a final action instruction code carrying the highest priority tripping reason (such as "overcurrent stage I on side 1" or "main transformer heavy gas"). Secondary priority processing (alarm-level events): If no trip-level event is detected in the current processing cycle, the event arbitration logic will continue to scan for events defined as alarm-level events. For example, if step S1 determines that a "TV disconnection" has occurred, a "TV disconnection alarm" judgment result is generated, which is an electrical quantity alarm event. Alternatively, if step S2 determines that a "main transformer oil level is low" has occurred, but its corresponding soft pressure plate is in an "exit" state, a "main transformer oil level low alarm" judgment result is generated, which is a non-electrical quantity alarm event. If the above alarm events are detected, the result of the comprehensive decision is "protection action conditions are not met" (i.e., no tripping), but one or more corresponding alarm command codes will be generated to drive panel lights, buzzers, or upload remote alarm information. Default state (normal level): If no "trip level" or "alarm level" event is found after scanning all inputs, the overall decision result is "protection action conditions are not met", and the device maintains normal monitoring state; It should be noted that by constructing a comprehensive protection decision, it is ensured that any serious fault that reaches the tripping level (whether electrical or physical) can be responded to without discrimination and with the highest priority. S4. When the integrated protection decision meets the preset protection action conditions, output control commands to drive the associated circuit breaker to operate. Furthermore, once the microprocessor in the NSC411U transformer substation monitoring and protection device receives the final action instruction code carrying the tripping reason issued by the event arbitration logic in step S3, it immediately starts the output processing program. The core task of this program is to map the logic instruction to the physical output. Furthermore, the microprocessor queries the internal preset output matrix configuration table based on the received action command code (e.g., "overcurrent stage I trip" or "main transformer heavy gas trip"). This configuration table defines the mapping relationship between each protection event and one or more physical output relays (DO), allowing users to flexibly configure which fault triggers which circuit breaker to trip. When the target output relay is located, the microprocessor sends a high-level signal to the relay's drive circuit through its I / O port. The drive circuit uses a 24V DC power supply provided by the device's internal power supply plug, isolated from the microprocessor, to excite the coil of the target output relay. After the coil is energized, its armature actuates, causing the normally open contact (NO) of the relay to close instantaneously. The closing action of this contact is the physical entity of the output control command in this invention. Specifically, for the closed output relay contacts, both ends are connected externally to the trip coil circuit of the associated circuit breaker inside the prefabricated substation. When the contacts are closed, the circuit is activated, allowing a strong operating current (in the range of 0.5A to 4A) to flow through the circuit breaker's trip coil. After being excited by the strong current, the trip coil generates sufficient electromagnetic force to drive the circuit breaker's tripping mechanism and release its mechanical latch. At this time, the circuit breaker can quickly trip under the action of the energy storage spring, thereby cutting off the fault current within milliseconds (the inherent action time of the fast-acting section is less than 40ms), isolating the fault point, and protecting the safety of the transformer and related power equipment. Furthermore, after outputting control commands to drive the circuit breaker, the microprocessor triggers the following tasks in parallel to ensure the integrity and traceability of fault information: The first task is for the microprocessor to immediately generate a structured event record from the fault event information that triggered this control command (including fault type, action time accurate to milliseconds, electrical quantity values ​​at the time of the fault, and protective elements that were activated), and store it in non-volatile memory for future reference. At the same time, the NSC411U transformer substation monitoring and protection device will immediately lock the ring waveform recording buffer that is running in its internal RAM. This buffer stores high-speed sampled waveform data of all key electrical analog quantities (such as Ia, Ib, Ic, Ua, Ub, Uc) in real time. According to the preset waveform recording strategy (e.g., "4 cycles before the fault, 6 cycles after the fault"), the microprocessor extracts complete waveform data segments before and after the fault occurrence time from the buffer to form a fault waveform recording file, and also transfers the fault waveform recording file to non-volatile memory. The second task is to push the circuit breaker action to the communication processing module of the NSC411U transformer substation monitoring and protection device. This module encapsulates the 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 back-end master station through RS485 or Ethernet interface. This allows operators to know the fault trip information of the transformer substation as soon as possible, thus realizing the "remote signaling" function in the "four remote" functions and improving the flexibility and intelligence level of transformer substation operation and maintenance.

[0028] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code. The solutions in the embodiments of this application can be implemented using various computer languages, such as the object-oriented programming language Java and the interpreted scripting language JavaScript.

[0029] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0030] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0031] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0032] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0033] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A comprehensive measurement, control, and protection method for prefabricated substations that integrates electrical and non-electrical quantity monitoring, characterized in that, include: Collect multiple electrical analog and non-electrical status signals in the prefabricated substation, compare the collected electrical analog quantities with preset electrical protection settings, and generate electrical protection judgment results based on electrical protection logic; Monitor the non-electrical quantity status signal and generate a non-electrical quantity protection judgment result based on the non-electrical quantity protection logic; Based on the judgment results of the electrical quantity protection and the judgment results of the non-electrical quantity protection, a comprehensive protection decision is made to determine whether the preset protection action conditions are met. When the integrated protection decision meets the preset protection action conditions, a control command is output to drive the associated circuit breaker to operate.

2. The integrated measurement, control, and protection method for prefabricated substations that integrates electrical and non-electrical quantity monitoring as described in claim 1, characterized in that, The acquisition of multiple electrical analog and non-electrical status signals within the prefabricated substation includes: Simultaneously, the electrical analog quantities of two power points on the high-voltage side and low-voltage side of the prefabricated substation are collected, and the two power points are executed independently. The collected electrical analog quantities are compared with the preset electrical quantity protection settings, and the electrical quantity protection judgment result is generated according to the electrical quantity protection logic.

3. The integrated measurement, control, and protection method for prefabricated substations that integrates electrical and non-electrical quantity monitoring as described in claim 1, characterized in that... The electrical analog quantities include three-phase current and three-phase voltage; the non-electrical quantity status signals are signals reflecting the status of the transformer itself, and the signals are at least one of switching signals and analog signals.

4. The integrated measurement, control, and protection method for prefabricated substations that integrates electrical and non-electrical quantity monitoring as described in claim 2, characterized in that, The step of generating an electrical quantity protection judgment result based on the electrical quantity protection logic includes: Its execution process includes at least one of the following protection judgment methods: overcurrent protection judgment, zero-sequence overcurrent protection judgment, overvoltage protection judgment, undervoltage protection judgment, and overload protection judgment.

5. The integrated measurement, control, and protection method for prefabricated substations that integrates electrical and non-electrical quantity monitoring as described in claim 4, characterized in that... The overcurrent protection judgment includes: The calculated value of any phase current among the collected three-phase currents is compared with at least one preset overcurrent setting. If the calculated phase current value continues to be greater than the overcurrent setting value, then the delay timer is started; When the delay time reaches the preset time value corresponding to the overcurrent set value, it is determined that the overcurrent protection condition is met.

6. The integrated measurement, control, and protection method for prefabricated substations that integrates electrical and non-electrical quantity monitoring as described in claim 1, characterized in that, The non-electrical quantity status signals include at least one switching quantity signal selected from transformer heavy gas, pressure release, low oil level, and high oil temperature.

7. The integrated measurement, control, and protection method for prefabricated substations that integrates electrical and non-electrical quantity monitoring as described in claim 6, characterized in that... Non-electrical quantity protection logic includes: Upon receiving the non-electrical quantity status signal, query the status of the protection activation / deactivation soft switch corresponding to the signal; If the soft pressure plate is in the engaged state, the non-electrical protection action condition is met; if the soft pressure plate is in the disengaged state, an alarm message is generated.

8. The integrated measurement, control, and protection method for prefabricated substations that integrates electrical and non-electrical quantity monitoring as described in claim 1, characterized in that, After outputting control commands to drive the associated circuit breaker, the following is also included: Record fault event information that triggers the control command; All electrical analog waveform data for a preset duration before and after the fault occurrence are extracted and stored in non-volatile memory.

9. The integrated measurement, control, and protection method for prefabricated substations that integrates electrical and non-electrical quantity monitoring as described in claim 1, characterized in that, It also includes a TV disconnection detection step, which is performed after the acquisition of multiple electrical analog and non-electrical status signals within the prefabricated substation, including: When it is detected that the three-phase phase voltages are all lower than the preset first voltage threshold and at least one phase current is greater than the preset current threshold, it is determined that the three-phase TV is disconnected. When the sum of the three-phase voltages is detected to be greater than the first voltage threshold and the minimum line voltage is less than the preset second voltage threshold, it is determined to be a single-phase or two-phase TV disconnection. When the sum of the three-phase voltages is detected to be 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 to be a single-phase or two-phase TV disconnection. Upon determining a three-phase TV circuit failure, a single-phase TV circuit failure, or a two-phase TV circuit failure, all electrical quantity protection functions that rely on voltage measurement are automatically locked.

10. The integrated measurement, control, and protection method for prefabricated substations that integrates electrical and non-electrical quantity monitoring as described in claim 1, characterized in that, It also includes a remote interaction step: The real-time telemetry data of the electrical analog quantities, the remote signaling data of the non-electrical quantity status signals, and the protection action events are uploaded to the remote monitoring center through a communication protocol, and the monitoring center's protection setting remote adjustment commands are received and executed.

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