A comprehensive measurement and control communication data unit adapted to distribution automation system

Abstract

The present invention discloses a comprehensive measurement and control communication digitization unit adapted to a power distribution automation system, which relates to the technical field of power distribution automation, and includes an interval unit and a common unit. The interval unit includes a module of a specific function or a specific circuit, specifically a CPU plug-in, an analog plug-in, a power output plug-in, and an input plug-in; the common unit includes a module shared by each interval unit, specifically a liquid crystal display plug-in; this comprehensive measurement and control communication digitization unit is installed on the following nodes of a 10kV ring network line: including a ring network power supply line, a single radial line, a branch line, and a circuit breaker or load switch cabinet of a low-resistance grounding system or a grounding system through an arc suppression coil. The present invention realizes rapid fault location, fault removal, fault isolation, and load transfer of a distribution line, and rapidly restores power supply to non-faulty areas.

Description

Technical Field

[0001] The present invention relates to the technical field of power distribution automation, and in particular to a comprehensive measurement, control, communication and data unit adapted to a power distribution automation system. Background Art

[0002] In modern power systems, 10kV distribution automation systems play a vital role. With the rapid development of social economy, the requirements for the reliability, stability and intelligence of power supply are constantly increasing. In order to meet these needs, distribution automation technology continues to develop and innovate. As one of the key equipment, the integrated measurement, control, communication and data unit plays an important role in the distribution system.

[0003] In the past, traditional distribution automation systems mainly adopted a centralized architecture, with a central control unit monitoring and controlling the entire distribution network. However, this architecture has some obvious limitations. For example, in some old industrial areas, during the operation of traditional distribution automation systems, once the central control unit fails, the distribution system in the entire area will be paralyzed, seriously affecting industrial production and residents' lives. In addition, the system response speed of the centralized architecture is slow, and it is difficult to meet the requirements of quickly handling faults and restoring power supply.

[0004] With the advancement of technology, distributed architecture has gradually become the development trend of distribution automation systems. Distributed integrated measurement and control communication data units can disperse monitoring and control functions to various nodes, improving the reliability and flexibility of the system. At the same time, the application of advanced communication technology and data processing algorithms enables these units to achieve more efficient information exchange and fault handling.

[0005] The Chinese patent with the authorization announcement number CN 101458504 B discloses a digital integrated protection and control unit with a multi-channel operation mode, including multiple independent and mutually information-sharing IED functional units that realize the merging function of multiple lines, relay protection function, intelligent operation function, and have synchronous measurement, control, recording, and system analysis functions; various Ethernet buses connected to each IED functional unit to realize the communication function; an intelligent operation unit that communicates with the control Ethernet and can collect the switch jump position, closing position, closing, and remote status, and can also collect user-defined remote signals; user-defined remote signals; and user protection units that can read relevant information from the IED functional unit, perform logical calculations, logical judgments, and logical result processing, and send their respective relevant information to the IED functional unit. This patent realizes resource information sharing conveniently and quickly on the spot without network communication, and uses a small amount of cables and has a simple structure.

[0006] Although the distributed intelligent station terminals developed by the above technology can conveniently and quickly realize resource information sharing on-site without network communication, and use a small amount of cables and have a simple structure, they have a low configuration, cannot quickly locate distribution line faults, and have poor data processing capabilities. Therefore, further development of a comprehensive measurement and control communication digitization unit that can quickly locate distribution line faults and improve data processing capabilities has become an inevitable trend in technological development. Summary of the invention

[0007] The technical problem to be solved by the present invention is to provide a comprehensive measurement and control communication digitization unit adapted to the power distribution automation system, so as to be able to quickly locate the distribution line fault and improve the data processing capability.

[0008] In order to solve the above technical problems, the technical solutions adopted by the present invention are as follows:

[0009] A comprehensive measurement, control, communication and digitization unit adapted to a power distribution automation system comprises an interval unit and a common unit. The interval unit comprises modules of specific functions or specific circuits, specifically a CPU plug-in, an analog plug-in, a power output plug-in and an input plug-in; the common unit comprises modules shared by each interval unit, specifically a liquid crystal display plug-in; the comprehensive measurement, control, communication and digitization unit is installed at the following nodes of a 10kV ring network line: including a ring network power supply line, a single radial line, a branch line and a circuit breaker or load switch cabinet of a low-resistance grounding system or a grounding system via an arc suppression coil.

[0010] Further preferably, a specially developed low-resistance grounding detection system is additionally installed on the low-resistance grounding system.

[0011] Further preferably, the low-resistance grounding detection system is powered by connecting to a constant micro power source, and uses a current sensor to collect data, and after interpolation, series expansion, and generation of a vector data layer, the grounding current variability in two or more corresponding intervals is numerically characterized by the direction, length, or composite data relationship of the vectors extracted in different intervals based on vector analysis, and compared with a fixed or feedback adjustable threshold, so as to determine whether the degree of grounding current variation reaches the warning or maintenance standard. Specifically, the data structure of the low-resistance grounding system includes: a discrete data layer; a continuous data layer; a linear data layer; a vector data layer; a grounding current variation characterization data layer. The data processing process includes: a. Power supply: set a connection to a constant micro power source to provide a weak current; b. Data acquisition: obtain current data points at a fixed sampling frequency through a current sensor to form a discrete data layer I0, I1, I2, I3...I n , where the subscript corresponds to the sampling interval ∆t1; c. Data interpolation: interpolate the discrete data layer and fit it to the continuous function I(t) to form a continuous data layer , where the superscript corresponds to the artificially selected larger interval ∆t2; d. Series expansion: Taylor series expansion is performed on the continuous function I(t) to obtain the linear data layer ; e. Vector data layer: extract the first k items from the linear data layer to generate n k-dimensional vectors , respectively , The subscript of corresponds to the superscript of In(t) above; f. Vector analysis: Based on the analysis of vector data, the variation characteristics of the grounding current are characterized by data to obtain the grounding current variation characterization data; the specific algorithm process is: through the direction, length or composite data relationship of the k-dimensional vector on different ∆t2 intervals, the variability of the grounding current in two or more corresponding ∆t2 intervals is numerically characterized; finally, the obtained data representation is compared with the pre-set fixed threshold or feedback adjustable threshold, and based on the data comparison result, it is determined whether the variation degree of the grounding current reaches the warning or maintenance standard.

[0012] Further preferably, the CPU plug-in is the core processing unit of the comprehensive measurement and control communication digitization unit, including data processing and logical judgment of telemetering, telesignaling, and remote control, executing algorithm calculation of optical fiber differential protection function and logical judgment of protection action, executing control logic and decision in feeder automation function, including master station centralized FA and local FA automation, processing protocol processing and data interaction in communication and management functions, waveform data collection for fault recording function, executing parameter setting and equipment self-diagnosis in debugging and maintenance functions, and executing data management in log, historical data storage and review functions.

[0013] Further preferably, the CPU plug-in includes a high-speed 32-bit ARM processor, equipped with a 16-bit high-precision external A / D chip, supports multiple independent network channels and multiple communication protocols, including RS-232, RS-485, Ethernet and other communication interfaces and IEC60870-5-101 / 104, IEC61850-MMS, IEC61850-GOOSE and other communication protocols, supports real-time peer-to-peer interactive communication between terminals, and provides 2 Ethernet ports, 1 fiber optic interface, and 2 serial ports.

[0014] Further preferably, the analog quantity plug-in includes analog signals such as AC voltage and current, which are converted into digital signals for processing by the CPU plug-in, providing a data source for the telemetry function.

[0015] Further preferably, the analog quantity plug-in includes an analog signal and two DC signals connected from the power distribution system, the analog signal includes a load side voltage, a power supply side voltage and a current signal, and the analog quantity plug-in converts the connected analog signal into a weak current signal suitable for CPU plug-in processing; a high-precision external A / D chip is used for AC sampling, and the measured voltage, current, frequency and calculated active power, reactive power, power factor and other parameters are supported for remote transmission, and the dead zone range of telemetry collection and upload is set by software; the analog quantity plug-in collects and records short-circuit current, zero-sequence current and zero-sequence voltage when a feeder fault occurs.

[0016] Further preferably, the power output plug-in is connected to a DC24V or DC48V power input with an input range of -20% to +20%, providing stable 24V and 5V DC power supplies for other parts of the terminal, and providing 8-way relay empty node output function. The power output plug-in is responsible for power management and monitoring, including power distribution of the management device and monitoring of the power status; the power output plug-in can use an external isolated power supply instead of the internal 24VDC as the contact input power supply.

[0017] Further preferably, the plug-in collects signals from 16 remote signal hard contacts to provide data for the remote signal function and collects necessary status signals for protection logic judgment. The DC / DC converter inside the plug-in device outputs an isolated 24VDC to provide input loop drive power for the dry contacts, allowing an external isolated power supply to be used instead of the internal 24VDC as the contact input power supply.

[0018] The beneficial effects of adopting the above technical solution are:

[0019] The present invention uses a high-speed 32-bit ARM processor configured by a CPU plug-in and is equipped with a 16-bit high-precision external A / D chip to ensure that the integrated measurement and control communication digitization unit has fast data processing capabilities;

[0020] The present invention supports multiple communication interfaces such as RS-232, RS-485, Ethernet, and communication protocols such as IEC60870-5-101 / 104, IEC61850-MMS, and IEC61850-GOOSE, ensuring the flexibility and compatibility of the communication of the integrated measurement and control communication digitization unit; supports real-time peer-to-peer interactive communication between terminals, which is important for distributed systems and improves the response speed and reliability of the system;

[0021] The present invention adopts a high-precision external A / D chip to perform AC sampling through an analog quantity plug-in, thereby ensuring the accuracy of telemetry data;

[0022] The present invention is responsible for power management and monitoring through the power output plug-in, including power distribution and status monitoring, which enhances the stability and reliability of the device;

[0023] The present invention collects signals from 16 remote signal hard contacts by inserting plug-ins, provides necessary status signals for the remote signal function, and enhances the monitoring capability of the system;

[0024] The present invention provides a 160*160 dot matrix LCD screen through an LCD display plug-in, which improves the user interaction experience and enables the user to conveniently view and set parameters;

[0025] The present invention newly constructs this low-resistance grounding detection system, which can detect the grounding condition of the casing, accurately determine whether its grounding is good, and issue an early warning and suggest maintenance. From the perspective of detection accuracy, we can analyze the changing characteristics of the grounding current in detail through multi-step data processing, gradually converting discrete data into continuous data and then extracting and converting linear data and vector data. Its significance is not only to improve the accuracy of detection, but also to improve the stability (generalization) of grounding detection under different grounding damage inducements in multiple environments. Finally, by numerically characterizing the variability of grounding current in different time intervals, possible potential problems can be discovered in time based on the changes in the actively applied grounding current, and pre-fault early warning and problem elimination can be performed (rather than processing during the fault and repairing after the fault). In addition, this specially developed grounding detection system can also adapt to different low-resistance grounding systems. By adjusting relevant parameters such as sampling frequency, interpolation interval, vector dimension, etc., especially vector dimension, it can always find the best sensitivity in the best detection performance, and achieve neither missed detection nor excessive false alarms while accurately warning. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a diagram of the optical differential protection transmission mechanism of the optical fiber differential protection function line configured by the present invention;

[0027] Figure 2 It is the action characteristic diagram of the current differential protection of the present invention;

[0028] Figure 3 It is the action logic diagram of the current longitudinal differential protection of the present invention;

[0029] Figure 4 It is the action logic diagram of the acceleration function after reclosing of the present invention;

[0030] Figure 5 It is the double-side voltage loss delayed opening logic diagram of the present invention;

[0031] Figure 6 This is the single-side incoming power delayed closing logic diagram of the present invention;

[0032] Figure 7 This is a single-side power-off delay closing logic diagram of the present invention;

[0033] Figure 8 It is the forward locking logic diagram of the present invention;

[0034] Fig. 9 It is the reverse blocking logic diagram of the present invention;

[0035] Fig.10 It is the logic diagram of the closing action of the pressure-locked switch on both sides of the present invention;

[0036] Fig.11 It is the comprehensive locking and closing logic diagram of the present invention. DETAILED DESCRIPTION

[0037] In order to make the features and advantages of the present invention more obvious and easy to understand, the technical solution will be clearly and completely described below in combination with the drawings and specific implementation methods. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0038] Our company's invention team has developed an integrated measurement and control communication digitization unit adapted to the 10kV distribution automation system. It is designed according to the distributed structure technology route and consists of several interval units and common units. Each unit of the integrated measurement and control communication digitization unit adopts a small structure, which is conducive to installation in the ring network cabinet. The integrated measurement and control communication digitization unit integrates the central FA and local FA protection functions of the master station, and can realize the logical functions of microcomputer integrated relay protection, optical fiber differential protection, voltage time feeder automation, voltage and current feeder automation, intelligent distributed feeder automation, etc. It can be installed anywhere in the 10kV ring network line, including the ring network power supply line and single radial line or branch line, the circuit breaker or load switch cabinet of the low resistance grounding system or the arc suppression coil grounding system, to realize the rapid fault location, fault removal, fault isolation and load transfer of the distribution line, and quickly restore the power supply to the non-fault area.

[0039] Example 1

[0040] The integrated measurement and control communication digitization unit adapted to the 10kV distribution automation system developed by the present invention team is code-named BHE-904 distributed station terminal.

[0041] The technical performance parameters of BHE-904 distributed station terminal are shown in Table 1.

[0042] Table 1 Technical performance parameters of BHE-904 distributed station terminal

[0043]

[0044]

[0045] A comprehensive measurement, control, communication and digitization unit adapted to a 10kV power distribution automation system comprises an interval unit and a common unit. The interval unit comprises modules of specific functions or specific circuits, specifically a CPU plug-in, an analog plug-in, a power output plug-in and an input plug-in; the common unit comprises modules shared by each interval unit, specifically a liquid crystal display plug-in. The comprehensive measurement, control, communication and digitization unit is installed anywhere on a 10kV ring network line, including a ring network power supply line and a single radial line or a branch line, a circuit breaker or a load switch cabinet in a low-resistance grounding system or a grounding system via an arc suppression coil.

[0046] The integrated measurement, control and communication data unit includes the following functions:

[0047] (1) Three remote functions

[0048] (1.1) Telemetry:

[0049] Capacity configuration: It can collect bus side and cable side voltage quantities (Ua1\Ub1\Uc1\U0\Uab2\Ubc2), 4 current quantities (Ia\Ib\Ic\I0), and 2 DC quantities; it supports sending the measured voltage, current, frequency, and calculated active power, reactive power, power factor and other parameters to remote transmission; DC quantity collection, such as backup battery voltage, supercapacitor voltage, etc.; the telemetry collection and upload dead zone range can be set through software, with line pressure identification and telemetry out-of-bounds alarm functions; it collects and records short-circuit current, zero-sequence current and zero-sequence voltage during feeder faults.

[0050] (1.2) Remote signaling:

[0051] Capacity configuration: Provide 16 telesignal hard contacts such as switch position and switch energy storage status; the DC / DC converter inside the device outputs isolated 24VDC to provide input circuit drive power for dry contacts. It is allowed to use external isolated power instead of internal 24VDC as contact input power; it has dual-position telesignal processing function and supports telesignal position change priority transmission; perfect soft telesignal status quantity, including: device abnormality, protection (including overcurrent, grounding) action, PT line break alarm current, switch lock signal, switch action reason and other soft telesignals; the telesignal input circuit adopts photoelectric isolation, and has software and hardware filtering measures to prevent input contact jitter or strong electromagnetic field interference malfunction, and the telesignal jitter pulse width (5ms~65000ms) can be set; it has event sequence recording function, records position change telesignal, accident telesignal, switch accident opening and closing times statistics, event SOE (resolution ≤2mS), etc., and can be sent to the distribution automation master station according to the requirements of the telesignal point table. The event sequence record SOE that was not sent when the communication was interrupted will be resent when the communication is restored, and will not be resent multiple times.

[0052] (1.3) Remote control: Capacity configuration: Supports remote activation of 1-way switch closing and opening energy storage control outlet and battery; receives and executes remote control commands from the distribution automation master station; remote control output contacts use dry contact output, and the pulse width time of each remote control contact output can be set independently; remote control is strictly carried out in the order of preset, return to school, and execution. After preset return to school, within the set time (default 60s), if the communication is interrupted or the execution command is not issued, the remote control command will be automatically canceled; it has remote control anti-misoperation measures to ensure the reliability of control operations; the same remote control point can only perform one-way authentication at the same time; it cyclically stores the latest 256 remote control operation records and supports uploading; it has a soft pressure plate to exit and enter the remote control function. If the soft pressure plate is not entered, the remote control will fail to execute; it also has a physical hard pressure plate for the control outlet. Warm reminder: At the same time, the unit supports the local panel closing and opening buttons to perform on-site manual closing and opening operations on the switch.

[0053] (2) The optical fiber differential protection function includes the current differential protection function and the CT disconnection judgment function.

[0054] like Figure 1 As shown, this device is equipped with line longitudinal differential protection, which is suitable for the differential current inflow and outflow between two places of cables or overhead lines without other loads and distributed power sources, so as to quickly determine and isolate the fault.

[0055] like Figure 2 As shown, the current differential protection function protection function:

[0056] 1) Start criterion: Id≥Idz;

[0057] 2) Ratio braking criterion: when Ir≤Irdz, Id≥k1Ir; when Ir>Irdz, Id-Id'≥k2(Ir-Irdz); where Id is the differential current, Id=|Im+In|, Id'=K1×Irdz;

[0058] Ir is the braking current, Ir=|Im-In|; Idz is the differential threshold, Irdz is the braking inflection point current constant;

[0059] k1 and k2 are ratio braking coefficients. For single-power supply lines, k1 is generally 0.3 and k2 is generally 0.5. For dual-power supply lines, k1 and k2 can be appropriately increased.

[0060] like Figure 3 As shown in the figure, when the CT ratios at both ends of the line are not equal, the current on the opposite side can be compensated by setting the "opposite current balance coefficient". When setting, the CT ratio on this side is used as the reference, and the ratio of the CT ratio on the opposite side to the CT ratio on this side is the "opposite current balance coefficient" of the device on this side. The differential current setting value on both sides is set based on the CT ratio on this side.

[0061] When an optical fiber communication abnormality occurs, the device will record "optical fiber communication abnormality", the "alarm" light will light up, and the longitudinal differential protection will be locked. At the same time, an alarm signal will be output. The signal output can be adjusted, and the alarm will return after the optical fiber communication is restored.

[0062] CT disconnection judgment function: In normal operation, the sum of the three-phase current is zero. When the CT is disconnected, the three-phase voltage is symmetrical (zero-sequence voltage is zero), and the sum of the three-phase current is not zero. In order to distinguish it from a ground fault, the following two judgments must be made:

[0063] (1) Among the three-phase currents, the phase with the smallest current has a value of zero;

[0064] (2) The current value of the phase with larger current is not zero and is less than the maximum load current.

[0065] When the CT line break alarm and CT line break interlock are activated at the same time, the longitudinal differential protection will be interlocked when the CT line is broken.

[0066] (3) Feeder automation function: BHE-904 distributed station terminal has centralized and local feeder automation (boundary and relay protection feeder automation, recloser feeder automation, intelligent distributed feeder automation) logic functions, which can be used with section point switches and contact point switches to achieve different protection logic functions. It can be selected through the "centralized / local" switch on the panel. At the same time, the panel is also equipped with a "section / contact" selection switch and a reclosing switch.

[0067] The "automation function" on / off switch of the terminal panel of the BHE-904 distributed station is the general enabling pressure plate for the protection logic function. The pressure plate is put into operation in conjunction with the corresponding functional soft pressure plate to realize the corresponding protection function. When the pressure plate is put into operation, the protection logic control function is started; when the pressure plate is withdrawn, the protection logic control function is withdrawn and all protection functions are invalid.

[0068] The BHE-904 distributed station terminal fault indication supports manual reset, automatic reset and master station remote reset functions. It can also automatically reset according to the set time or after the line resumes normal power supply.

[0069] (3.1) Master station centralized feeder automation: This terminal has the "three remote" function and can establish optical fiber and wireless communication channels with the master station. Fault handling in this mode relies on communication with the master station. The master station system locates the fault based on the unit fault alarm information, determines the fault type and section, and the master station sends a remote control command to the unit to complete the fault isolation and restore power supply to the non-fault area.

[0070] (3.2) If Figure 4 As shown in the figure, IGLset is the overcurrent setting value; THJSset is the limit value during post-acceleration action; IN is the current of any phase.

[0071] Relay protection feeder automation includes phase-to-phase overcurrent protection, zero-sequence overcurrent protection, overload protection, small current grounding fault identification, acceleration function after reclosing, overcurrent triggering, no-voltage and no-current delayed opening, non-interrupting current protection, excitation inrush current protection, and overvoltage protection.

[0072] When used with a circuit breaker, it has the function of directly removing faults, and has a reclosing function, and supports sending fault events. When used with a load switch, it combines the action logic of the substation outgoing line switch to achieve effective fault isolation and support sending fault events.

[0073] If the matching switch is installed at the end or branch of the line, the function of the traditional boundary switch can be realized through the setting of the three-stage protection function. When a single-phase grounding or short circuit fault occurs within the boundary, the output of the trip signal switch body trips and isolates the fault. When a single-phase grounding or short circuit fault occurs outside the boundary switch, the switch does not operate.

[0074] Phase-to-phase overcurrent protection: It has three stages of overcurrent protection: quick-break, time-limited quick-break and overcurrent protection. You can select to put it in / out through the soft pressure plate. Detect the three-phase current. When the current is greater than the current setting value, it will output the alarm and trip (circuit breaker) command after the adjustable delay, and light up the overcurrent signal light. The protection action time limit, current setting value, and export mode can be set, as well as the secondary action current (0~20In) and trip delay (0~99.99S).

[0075] Zero-sequence overcurrent protection: It has two-stage protection, and can set the protection action time limit (0-99.99S), current setting value (0-20In), and exit mode (trip or alarm). This protection can be selected to be enabled / disabled through the soft pressure plate.

[0076] Overload protection: alarm and tripping can be set. When the current is greater than the current setting value, the device lights up the signal light after an adjustable delay, generates an alarm soft remote signal, or trips the output. The current (0-20In) and time setting value (0-99.99S) can also be set separately. The protection can be selected to be enabled / disabled through the soft pressure plate.

[0077] Low resistance ground fault identification: Supports steady-state zero-sequence current detection, directional grounding and transient method for ground fault detection. By analyzing the transient waveform characteristics of zero-sequence voltage and zero-sequence current, it can detect and distinguish ground faults under different neutral point grounding methods, and supports sending fault events. This protection can be selected to be enabled / disabled through the soft pressure plate.

[0078] In actual applications, due to the influence of external factors such as the vibration of the machine's cooling system, the grounding wire head will vibrate and loosen. In this case, the grounding safety of the product may have been seriously affected, but the current will usually only fluctuate during detection, and the mean value of the current may not necessarily decrease. Therefore, the method of simply relying on the current size to judge whether the chassis grounding is good is not reliable. Based on this discovery, the team of the present invention has developed a more accurate data model after in-depth research. This model is specifically used for ground fault detection and fault discrimination functions. Generally speaking, in low-voltage electrical equipment, the protective grounding resistance should not be greater than 4 ohms. In some places with high grounding requirements, such as electronic equipment rooms, the grounding resistance requirements may be more stringent, usually requiring no more than 1 ohm. For high-voltage systems, the grounding resistance requirements will be determined based on factors such as the system's voltage level, grounding method, and specific application environment. For example, in a small grounding current system of 10kV and below, the grounding resistance is usually no more than 10 ohms; while in a large grounding current system, the grounding resistance may be smaller.

[0079] The newly developed grounding safety detection architecture is different from the spot check and regular inspection in the existing technology. It considers giving the grounding wire a constant power supply. At the same time, in order to save energy, we set the constant power supply to a tiny power supply of about 0.01-0.5v, which generates a weak current (the corresponding energy consumption is almost negligible); at the same time, the current point value (discrete data layer) at a fixed sampling frequency is obtained through the current sensor. , where the subscript corresponds to the sampling interval ∆t1, for example, sampling once per minute. Under such a technical route, since the current is relatively weak, a corresponding current data feature extraction and processing method is required, and this processing method is preferably adjustable to adapt to various environmental changes (such as the above-mentioned heat dissipation or other mechanical vibrations on grounding, etc.) for the requirements of robust characteristics of grounding detection.

[0080] Specifically speaking about the problem of feature extraction, for the micro-current point values ​​sampled in a constant micro-power environment, they are first fitted into a continuous function (continuous data layer) by interpolation method. , where the superscript corresponds to a larger interval ∆t2 that is artificially selected, such as fitting once a day.

[0081] right Perform Taylor series expansion to obtain the linear data layer ; Here, through the data processing method of series expansion, it is possible to easily extract the data features of the adjustable curve, and it has the adjustability required above; for example, if we can take the first three continuous functions for data testing, we can get the final desired test effect, then we can use the first three continuous functions for testing; if the first three continuous functions cannot achieve the final desired test effect, we will continue to increase the number of continuous functions, for example, take the first five continuous functions, the first seven continuous functions, and so on, until the final desired test effect of grounding safety detection is achieved.

[0082] Next, take the first k items of the linear data level to get n k-dimensional vectors , respectively , The subscript of the above I n The superscripts of (t) correspond to each other; thus, the vector space data layer is obtained.

[0083] By analyzing the internal data structure characteristics of the vector space data layer, the grounding state variation warning is carried out. The specific calculation program is constructed as follows: . Among them, the numerator corresponds to the inner product of the vectors derived from different large intervals. It is easy to see mathematically that the size of the inner product corresponds to the consistency of the directions of the two vectors. For example, when the inner product is 1, it means that the directions of the two vectors are consistent, which means that the fitted continuous function curves are completely consistent, indicating that the current has no fluctuations and the grounding is normal; conversely, if the inner product is 0, it means that the two vectors are perpendicular, the current fluctuates greatly, and the grounding is abnormal. This gives a valuable hint, that is, by calculating the inner product of the vectors, a variation parameter of 0-1 can be obtained to detect the grounding condition of the casing of the multifunctional intelligent box transformer monitoring device used in new energy power stations. At the same time, the absolute value product of the length of the vector corresponding to the denominator is divided, and the calculated variation parameter based on the vector consistency inner product is expressed as a percentage. For example, Set it as the first large interval ∆t2, such as the value of the first day, at which time the equipment is considered to be in good condition. is the value of the nth day; after the data features are extracted and calculated through the above data program, a threshold is set (the threshold is of course adjustable, and in particular, it can be adjusted and optimized by post-feedback). For example, when the variation parameter is less than 60%, it is considered that a large variation has occurred. At this time, an early warning will be issued and maintenance will be recommended.

[0084] Acceleration function after reclosing: The front panel operation is equipped with a "reclosing" function throw-in / out switch, which can be used to realize the on-site throw-in / out operation of this function. Two automatic reclosing can be set, and the number of reclosing and the delay setting value of each reclosing can be set as needed. The three-stage overcurrent protection and zero-sequence protection can start the reclosing function, and the manual opening does not start the reclosing function. Supports the function of locking the secondary reclosing, and the time limit value of locking the secondary reclosing can be set. If a fault current is detected within the set time (adjustable) after the first reclosing, the secondary reclosing will be locked.

[0085] Supports the post-reclosing acceleration function. After successful reclosing, if the fault current is still detected, the post-reclosing acceleration function will be started according to the settings (the post-acceleration time can be set), the unit tripping output will be activated, and the fault current will be cut off. This protection can be selected to be enabled / disabled through the soft pressure plate.

[0086] In order to ensure the reliability and stability of the reclosing switch, charging conditions are set. The reclosing switch can only be started when the charging conditions are met.

[0087] Overcurrent triggering, no-pressure and no-current delayed tripping: When used with a matching load switch, the tripping pressure plate and this function pressure plate must be set at the same time. After detecting the fault current, the tripping action must be performed after no pressure and no current are met. Otherwise, the load switch will trip directly and there is a risk of cabinet explosion. The no-pressure, no-current and delay settings can be adjusted, and the protection can be selected to be enabled / disabled through the soft pressure plate.

[0088] Non-interrupting current protection: When the fault current exceeds the breaking capacity of the load switch, the non-interrupting current protection is activated, the switch is prohibited from opening, and the interrupting current setting value (0~20In) can be adjusted. This protection can be selected to be turned on / off through the soft pressure plate.

[0089] Excitation inrush current protection: Identify the characteristics of the excitation inrush current in the current loop to prevent the unit from malfunctioning when the user's large-capacity transformer is closed.

[0090] If one or more of the protection phase currents (IA, IB, IC) exceed the set current value, and the harmonic content of the corresponding phase is measured to exceed the inrush current blocking value, it is considered that there is an instantaneous large current impact and the outlet does not operate. This function is used in conjunction with the three-stage current protection, and the inrush current blocking value can be set. This protection can be selected to be enabled / disabled through the soft pressure plate.

[0091] Overvoltage protection: detect phase voltage (busbar UA, UB, UC). When one or more phase voltages are greater than the voltage setting value, protection tripping or alarm action can be performed according to the settings. This protection can be selected to be enabled / disabled through the soft pressure plate, and the voltage, time setting value, and output mode can also be set separately.

[0092] (3.3) Local feeder automation: This mode does not rely on communication with the master station, and can locate, isolate and restore faults locally. This is achieved through the switch's "no-voltage opening, delayed closing on incoming power" operating characteristics combined with the substation outgoing switch's secondary closing. The primary closing isolates the faulty section, and the secondary closing restores power to the non-faulty section. There are two different operating modes set as the switch's section point or contact point, and only one operating mode can be put into operation at most.

[0093] In the segment point mode, it has the following functions, each of which can be activated or deactivated by the soft pressure plate:

[0094] a. Figure 5 As shown in the figure, Umax1 is the maximum value of Uab1 and Ubc1 on the load side; Umax2 is the maximum value of Uab2 and Ubc2 on the power supply side; USYset is the double-sided voltage loss setting value; TSYset is the double-sided voltage loss delay setting value.

[0095] The function of opening the switch after voltage loss on both sides is not locked. The switch opens after voltage loss on both sides (adjustable). In order to avoid malfunction of protection caused by voltage loss on the load side when the device is powered on, the device sets the voltage sign after the load voltage or power supply voltage is normal before starting the voltage loss opening action. This protection action logic is applicable to section switches or contact switches.

[0096] b. Figure 6 As shown in the figure, this protection action logic is only applicable to sectionalized switches. In the figure, Umin1 is the minimum value of Uab1 and Ubc1 on the load side; Umin2 is the minimum value of Uab2 and Ubc2 on the power supply side; UYYset is the voltage setting value; TLDset is the power-on delay setting value; when the single-side power-on delay closing function is not locked, the switch is in the open position, one side has voltage and the other side has no voltage, and the power-on delay (X time limit) time is up, the switch is controlled to close; Figure 7 As shown, this protection action logic is only applicable to the contact switch. In the figure, Umin1 is the minimum value of Uab1 and Ubc1 on the load side; Umin2 is the minimum value of Uab2 and Ubc2 on the power supply side; Umax1 is the maximum value of Uab1 and Ubc1 on the load side; Umax2 is the maximum value of Uab2 and Ubc2 on the power supply side; UYYset is the voltage set value; TSDHZset is the single-side power failure delay closing time set value. In order to prevent the single-side power failure delay closing from repeated actions, a "charging" counter is set in each action logic. If the following 7 conditions are met at the same time and the delay is 15 seconds, the power failure delay closing charging flag is set and the closing lock flag is cleared. If any condition is not met, the circuit breaker will be discharged immediately.

[0097] c. Reverse blocking closing function (X blocking): Fig. 9As shown in the figure, TLDset is the incoming power closing delay setting, TSDHZset is the power-off closing delay setting, and the residual voltage pulse condition is detected when the voltage of Uab1 or Ubc1 is greater than the residual voltage setting and the duration is between 20MS-2000MS, or the voltage of Uab2 or Ubc2 is greater than the residual voltage setting and the duration is between 20MS-2000MS. Either of the two conditions can be met; the X-locked closing flag is set to lock the reverse closing, and the X-locked closing flag is cleared when the manual closing, remote control closing or forward incoming power exceeds X time. When a power failure occurs within the X time limit for more than the Z time limit, the unit enters the X-time limit locked state; reverse power supply is prohibited, and the lock indicator light is on.

[0098] d. Forward blocking closing function (Y blocking): Figure 8 As shown in the figure, Umax1 is the maximum value of Uab1, Ubc1 on the load side, and Uab2, Ubc2 on the power supply side; USYset is the double-side voltage loss setting; Y is the forward locking time. After the switch is closed (including manual closing, manual unlocking delay closing, and normal power-on delay closing), if there is voltage loss within the Y time limit, the switch will be opened and forward locked and closed; the Y locking closing flag is set to lock the forward closing, and the Y locking closing flag will be cleared after manual closing, remote control closing or reverse call exceeds X time.

[0099] e. Close to zero voltage and open and lock the closing function

[0100] After the switch is closed, if a zero-sequence voltage signal is detected within the Y time limit, the switch will be opened and locked to cut off the ground fault; if a zero-sequence voltage signal is detected outside the Y time limit, or there is a zero-sequence voltage before the switch is closed, the locking closing function will not be executed.

[0101] f. Residual voltage pulse blocking and closing function has residual voltage pulse (residual voltage value is ≥30% rated voltage, and the lower limit of pulse time is not more than 40ms) detection function. Within the X time limit, it supports residual voltage detection in the non-shutdown state, and can also realize the identification and memory of residual voltage pulse in the shutdown state (backup power supply is not put into use). After the controller is powered on, the identified residual voltage pulse can be involved in the logic operation and reverse blocking and closing function.

[0102] g. Manual opening locking function Manual opening (manual opening by local controller, opening by switch operating lever and remote control opening) locking closing function.

[0103] h. Short-time locking and opening function: If the switch does not open due to loss of pressure within the set time (adjustable) after closing, the opening function will be locked and released after a delay.

[0104] i. When the switch is in the open position, the automatic closing function is prohibited when there is pressure on both sides.

[0105] j. Continuous opening and closing function: If the number of continuous openings exceeds the limit (settable, the initial value is 3 times / 10min) within the set time, the switch will be locked and closed.

[0106] In the contact point mode, the following functions are available, and each function can be activated or deactivated by the soft pressure plate. Contact function activation conditions: the switch is in the open position, there is pressure on both sides and the set time is reached, the unit automatically releases the lock and closes, and enters the single-side pressure loss delay closing working state.

[0107] a. Delayed closing when voltage is lost on one side

[0108] When the switch is in the open position, there is pressure on both sides and the set time (Y time limit) is reached, the unit automatically releases the lock and closes, and enters the single-side pressure loss delay (XL time limit) closing

[0109] b. After the residual voltage pulse locking closing function is started, during the single-side pressure loss delay closing timing (the switch is not closed), a residual voltage pulse is detected on the pressure loss side (the residual voltage value is 30%-100% of the rated voltage, and the lower limit of the pulse time is not more than 40ms), and the closing is locked.

[0110] c. Fig.10 As shown, manual closing, remote control closing or simultaneous loss of pressure on both sides for more than Z time clears the pressure-locked closing signs on both sides, and when the double-side pressure-prohibited closing function switch is in the open position, the double-side pressure-prohibited automatic closing function.

[0111] d. The switches for the pressure loss tripping function on both sides are in the closed position, the pressure loss on both sides will delay the tripping and lock the energized closing on one side.

[0112] e. Fig.11 As shown, manual closing, remote control closing or simultaneous loss of pressure on both sides for more than Z time to clear the pressure on both sides, lock closing marks, manual opening, locking and closing functions.

[0113] (3.4) Intelligent distributed feeder automation function

[0114] BHE-904 distributed station terminal has intelligent distributed logic function, which can be switched on and off through soft pressure plate. Intelligent distribution enables each terminal in the ring network to exchange information with each other through peer-to-peer communication between terminals. After the fault, the switches on both sides closest to the fault point are directly tripped within milliseconds, minimizing the power outage area. At the same time, the contact switch automatically closes and transfers the power.

[0115] The communication between BHE-904 distributed stations and terminals is based on the GOOSE service model in the IEC61850 standard system. The GOOSE mechanism is similar to the GOOSE mechanism based on IP network in IEC61850-90-5.

[0116] The intelligent distributed mode requires the establishment of a fiber-optic peer-to-peer communication channel between each terminal. Through different logical function settings, two intelligent distributed working modes, fast-acting and slow-acting, can be realized. The fast-acting mode can achieve millisecond-level fault location and isolation, and the slow-acting mode requires a station trip.

[0117] The main functions are as follows: Fast-acting type: When a line fault (grounding or short circuit) occurs, before the outgoing line switch protection of the substation is activated, the terminals can communicate with each other to achieve the automatic location and isolation of the fault and the automatic restoration of power supply to the non-fault area, and report the processing process and results to the distribution automation master station. Slow-acting type: When a line fault (grounding or short circuit) occurs, after the outgoing line switch protection of the substation is activated, the terminals can communicate with each other to achieve the automatic location and isolation of the fault and the automatic restoration of power supply to the non-fault area, and report the processing process and results to the distribution automation master station.

[0118] a. Rapid fault location and isolation function. It has the function of isolating the fault of the outgoing line at the power supply point; it has the function of isolating the busbar fault within the distribution station; it has the function of isolating the line fault between distribution stations; it has the function of isolating the feeder line fault within the distribution station;

[0119] b. Automatic closing and power transfer function of the contact switch When a line fails, the switch in the contact position will make a judgment on closing or keeping open based on the isolation of the fault section and whether it has the load transfer capability, and complete the restoration of power supply to the non-fault area. The whole process should be completed before the substation outgoing line circuit breaker is reclosed. When there are multiple contact switches at the same time, the load can be transferred to multiple contact switches according to the set priority order.

[0120] c. Abnormal situation handling function

[0121] When an abnormal situation occurs, the relevant functions of the distributed FA are locked, and an alarm is sent to the distribution master station and the reason for the lockout is reported; at the same time, without affecting safety conditions, when an abnormality occurs, a logical strategy of appropriately expanding the isolation area is adopted to isolate the fault area to a smaller range as much as possible, and restore power supply to the non-fault area.

[0122] When any switch fails to operate or the switch fails to operate, a request is quickly sent to the nearest upstream circuit breaker to trip, so that the scope of power failure is kept to a minimum. When any distribution terminal fails, the adjacent device will detect the GOOSE communication interruption and alarm. When a fault occurs, it will be extended to the upper level circuit breaker to trip, so that the scope of power outage is kept to a minimum. When the voltage transformer fails and the direction signal fails, it can switch to the non-directional protection mode and continue the intelligent distributed logic processing. The fault processing scope is only extended to the upper level circuit breaker.

[0123] When communication interruption occurs, the distribution terminal sends a reliable GOOSE communication interruption alarm signal and continues intelligent distributed logic processing. The fault processing scope is only expanded to the upper-level circuit breaker.

[0124] It has backup protection function and can be switched in and out. When communication is interrupted in any link and the fault cannot be accurately located, the intelligent distributed logic will not be executed and the backup protection switch designated in the line will trip.

[0125] The interconnecting switch is locked and closed when in maintenance state. If the interconnecting switch loses pressure on one side and the delay time expires and no fault isolation information is received, the interconnecting switch will be locked and closed.

[0126] d.FA information generation function

[0127] The unit generates FA action information based on the fault handling process and results and reports it to the distribution automation master station. The main information includes the distributed FA system switch status signal, the distributed FA related feeder switch action start signal, the distributed FA related feeder switch action normal end signal, the distributed FA related feeder switch action refusal signal, and other FA abnormal end signals.

[0128] e. Plug and Play function, automatic registration of information subscription / publishing model transmission service

[0129] f. Surface protection function of network communication When a line fails, adjacent terminal units exchange the positions of all switches on the line, protection fault information and current and voltage measurements through peer-to-peer communication, determine the switches on both sides of the fault section that are directly electrically connected, and start tripping with positive or reverse protection to achieve high-speed fault location and fault isolation.

[0130] g. Network flow self-identification function When the operating mode changes, the unit has the function of self-identification of flow direction.

[0131] (4) Communication and management functions

[0132] a. Support RS-485 / RS-232 communication, equipped with 2 reusable interfaces, and configurable transmission rate;

[0133] b. Support 10 / 100BASE-T adaptive Ethernet network communication, equipped with 2 Ethernet communication interfaces;

[0134] c. Communication with the master station supports optical fiber or wireless communication; communication with the public unit supports serial port or Ethernet port communication.

[0135] d. Support SNTP time synchronization, protocol and other time synchronization methods, receive time synchronization commands from the master station or other time synchronization devices, and keep synchronization with the system clock. Support time synchronization of each interval unit through SNTP and other time synchronization methods.

[0136] e. Support IEC60870-5-101IEC60870-5-104 communication protocols, Modbus multiple protocols; can receive status monitoring, standby automatic switching and other equipment data functions.

[0137] f. Distributed FA information interaction adopts GOOSE protocol. The fault information interaction message delay time of fast-moving distributed FA peer-to-peer communication is ≤20ms; the fault information interaction message delay time of slow-moving distributed FA peer-to-peer communication is ≤200ms.

[0138] g. The panel has local status indicators for each communication port, making it easy to observe the communication status of the interface.

[0139] (5) Fault recording function

[0140] a. It can store 64 groups of recorded data in a loop, and support uploading to the main station, and support local export and saving / viewing of recorded data;

[0141] b. The recording content includes the waveform data of 4 cycles before the fault occurs and 8 cycles after the fault occurs, and the recording points are 80 points / cycle;

[0142] c. The recorded data includes voltage, current, switch position, etc.;

[0143] d. The start-up conditions of the recording function include overcurrent fault, line voltage loss, zero-sequence voltage, zero-sequence current mutation, etc. The start-up condition parameters can be set remotely and locally;

[0144] e. The recording file format follows the format defined in the Comtrade1999 standard, using two files: CFG (configuration file, ASCII text) and DAT (data file, binary format).

[0145] (6) Debugging and maintenance functions

[0146] a. Maintenance and management of parameters and fixed values ​​Receive remote parameter and fixed value calls and modification commands; display and modify parameters and fixed values ​​locally using maintenance background software or directly on the unit LCD panel; the background maintenance software has the function of backing up and importing unit parameters and fixed values;

[0147] b. Equipment self-diagnosis and self-recovery function

[0148] Real-time detection of important chips such as AD and EPROM inside the device, alarm to the main station (substation) and reflect the real-time working conditions when abnormal;

[0149] Real-time detection of the working status of telemetry, telesignaling, remote control and other functional plug-ins, and alarm to the main station (substation) and reflect the real-time working conditions when abnormal;

[0150] It has soft and hard watchdogs to monitor the program running status in real time and automatically reset and restart when an abnormality occurs; the communication ports such as the serial port and Ethernet port have software watchdogs, which can automatically reset the port when no data is sent or received for a long time.

[0151] c. Local debugging and maintenance functions

[0152] Equipped with 160*160 dot matrix LCD and pure Chinese interface, it can realize real-time working condition display, parameter setting, protection setting value setting, unit debugging, fault diagnosis, event record display and other functions on-site;

[0153] Provides manual closing / opening buttons and protection throw-in / out switches, which can directly complete local manual opening and closing operations and configuration-related operations of protection functions.

[0154] It supports manual reset, automatic reset, and master station remote reset for fault indication. It can automatically reset according to the set time or after the line returns to normal. It can also automatically select the reset method according to the nature of the fault (transient or permanent).

[0155] (7) Log and historical data storage and review functions

[0156] Supports remote access to historical data, which can be uploaded to the distribution network master station in the form of files; historical data includes: event sequence records, remote control operation records, daily frozen electricity, electric energy fixed-point data, power fixed-point data, voltage fixed-point data, current fixed-point data, voltage daily extreme value data, current daily extreme value data, etc.

[0157] Supports historical data recording and cyclic storage functions, and saves data after power failure. It stores the latest 31 days of fixed-point records and extreme value records, 1024 event sequence records, and 256 remote control operation records. Fixed-point data generates 96 records at equal intervals every day, and extreme value records generate 1 record every day.

[0158] It has a log recording function, including information such as system login, abnormal status, parameter modification, etc. It provides a dedicated debugging and maintenance communication interface RS232 and Ethernet interface for maintenance tools; the unit panel is equipped with various operating indicators, which can intuitively judge the working status of the equipment; the unit supports the telemetry manual setting function, and the actual increase of the amount is not required during power outage installation, and the measurement point position calibration of the device and the distribution automation system telemetry data can be completed, which is convenient for on-site installation and debugging.

[0159] Dedicated maintenance background software: It has application functions such as unit operation parameter setting, unit operation condition monitoring, line protection setting value setting, forwarding configuration setting, real-time data monitoring, analog quantity accuracy verification, three-telemetry table configuration, historical record reading and exporting; it has communication message monitoring function.

[0160] Example 2

[0161] The hardware of the integrated measurement, control, communication and data unit is as follows:

[0162] The device adopts front LCD display and rear plug-in structure, which is easy to install and maintain. It is divided into CPU plug-in, power output plug-in, analog plug-in and LCD display plug-in.

[0163] (1)CPU plug-in

[0164] The CPU plug-in uses a high-speed 32-bit ARM processor and 16-bit AD to complete data collection, processing and communication functions, and provides 2 Ethernet ports, 1 optical fiber interface, and 2 serial ports.

[0165] (2) Analog plug-in The analog plug-in completes the access of load side voltage (Ua1, Ub1, Uc1, U0), power side voltage (Uab2, Ubc2), current (Ia, Ib, Ic, I0) and two DC quantities, and converts them into weak current signals for use by the CPU plug-in;

[0166] (3) Power outlet plug-in

[0167] The power output plug-in supports DC24V / DC48V input, outputs 24V and 5V for other plug-ins, and provides 8-way relay empty node output;

[0168] (4) Open the plug-in

[0169] The plug-in completes the acquisition of 16-channel telemetering information. The DC / DC converter inside the device outputs isolated 24VDC to provide input circuit drive power for the dry contacts. It is allowed to use an external isolated power supply instead of the internal 24VDC as the contact input power supply;

[0170] (5) LCD display plug-in

[0171] The LCD display plug-in uses a 160*160 dot matrix LCD and a pure Chinese interface, which can complete real-time working condition display, parameter setting, protection setting value setting, unit debugging, fault diagnosis, event record display and other functions on-site.

[0172] The present invention has the following characteristics:

[0173] (1) The terminal uses a powerful 32-bit high-end ARM processor with strong processing power, parallel data acquisition and data calculation processing, and uses a 16-bit high-precision external A / D chip for AC sampling. It has powerful communication management capabilities, provides independent multi-network channels and protocol support, provides multiple communication interfaces such as RS-232, RS-485, Ethernet, and communication protocols such as IEC60870-5-101 / 104, IEC61850-MMS, IEC61850-GOOSE, and can realize real-time peer-to-peer interactive communication between terminals, and realize rapid fault location of distribution lines, rapid on-site fault isolation, rapid transfer of power supply loads, and rapid self-healing of power supply to non-fault areas.

[0174] (2) It has complete local FA logic functions, which can realize the functions of local fault monitoring, positioning, isolation and power restoration in non-fault areas. It supports fast-acting and slow-acting distributed feeder automation functions based on peer-to-peer communication; it supports voltage-time type and voltage-current type feeder automation functions that do not rely on communication; it has optical fiber longitudinal differential protection function.

[0175] (3) The terminal integrates multiple feeder automation functions such as control, monitoring, signaling, communication, measurement, event recording, and protection.

[0176] (4) The terminal uses a high-precision clock chip inside and has the function of receiving SNTP network time synchronization from the power distribution master station.

[0177] (5) The terminal has the functions of fault recording and fault waveform recording, supports 64 sets of waveform recording data cyclic storage, 80 points sampling per cycle, records four cycles before the fault and eight cycles after the fault; the waveform recording file can be uploaded to the host computer through the network interface, and the fault waveform can be analyzed by the host computer software.

[0178] (6) The terminal uses a large-screen Chinese character LCD display and menu operation mode, with a good human-machine interface. The set value data, control word meaning, switch input, and fault information are all displayed in Chinese characters, which is very convenient for on-site adjustment and viewing.

[0179] (7) When a backup power management device is configured externally, the terminal has a battery management function, including battery voltage information collection, external power supply failure, battery failure, battery charging failure and other collection functions, and also has a remote battery activation function.

[0180] (8) The terminal has self-diagnosis and self-recovery functions. It can perform self-diagnosis on various functional boards, important chips, etc., send alarm information when abnormalities occur, and automatically reset when software abnormalities occur.

[0181] (9) The terminal has the function of local and remote access and configuration of unit operating parameters. The configuration parameters include zero threshold value (zero drift), change threshold (dead zone), heavy overload alarm limit, short circuit and ground fault action parameters, etc.

[0182] (10) The terminal has the function of local and remote access to the unit's inherent parameters, including terminal type and factory model, terminal ID number, embedded system name and version number, hardware version number, software checksum, communication parameters and secondary transformation ratio, etc.

[0183] (11) The terminal has the function of cyclic storage of historical data. The data will not be lost after power failure and can be accessed remotely. The historical data includes remote signal changes with time stamps, remote control operation records, daily frozen power, fixed-point data, extreme value data, etc.

[0184] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0185] In each embodiment, the hardware implementation of the technology can directly adopt existing intelligent devices, including but not limited to industrial computers, PCs, smart phones, handheld stand-alone machines, floor-standing stand-alone machines, etc. Its input device preferably adopts a screen keyboard, its data storage and calculation module adopts existing memory, calculator, controller, its internal communication module adopts existing communication ports and protocols, and its remote communication adopts existing GPRS networks, World Wide Internet, etc. It can be clearly understood by technicians in the relevant field that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example. In actual applications, the above-mentioned function allocation can be completed by different functional units and modules as needed, that is, the internal structure of the device is divided into different functional units or modules to complete all or part of the functions described above. Each functional unit and module in the embodiment can be integrated in a processing unit, or each unit can exist physically separately, or two or more units can be integrated in one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of each functional unit and module are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application. The specific working process of the units and modules in the above-mentioned system can refer to the corresponding process in the above-mentioned method embodiment, and will not be repeated here. The functional units in the various embodiments of the present invention can be integrated in a processing unit, or each unit can exist physically separately, or two or more units can be integrated in one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of a software functional unit. If the integrated module / unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the present invention implements all or part of the processes in the above-mentioned embodiment method, and can also be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium, and the computer program can implement the steps of the above-mentioned various method embodiments when executed by the processor.

[0186] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein with equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the scope of protection of the claims of the present invention.

Claims

1. A comprehensive measurement, control, communication and data unit adapted to a power distribution automation system, characterized in that: It includes an interval unit and a common unit. The interval unit includes a CPU plug-in, an analog plug-in, a power output plug-in, and an input plug-in; the common unit includes a module shared by each interval unit, specifically a liquid crystal display plug-in; this comprehensive measurement and control communication data unit is installed at the following nodes of the 10kV ring network line: the ring network power supply line, the single radial line, the branch line, and the circuit breaker or load switch cabinet of the small resistance grounding system or the arc suppression coil grounding system; A low-resistance grounding detection system is additionally installed on the low-resistance grounding system. The low-resistance grounding detection system is powered by connecting to a constant micro power supply, and uses a current sensor to collect data and interpolate, expand it in series, and generate a vector data layer. Specifically, first, the current data points are acquired by the current sensor at a fixed sampling frequency to form a discrete data layer; then the discrete data layer is interpolated and fitted to a continuous function to form a continuous data layer; then the continuous function is expanded in a Taylor series to obtain a linear data layer; finally, the first k items are extracted from the linear data layer to generate n k-dimensional vectors to obtain a vector data layer; based on vector analysis, the direction, length or composite data relationship of the extracted vectors in different intervals is used to numerically characterize the variability of the grounding current in two or more corresponding intervals, and compared with a fixed or feedback adjustable threshold, so as to determine whether the degree of grounding current variation reaches the warning or maintenance standard.

2. The integrated measurement, control, communication and data unit for power distribution automation system according to claim 1, characterized in that: The CPU plug-in is the core processing unit of the comprehensive measurement and control communication digitization unit, including data processing and logical judgment of telemetering, telesignaling, and remote control, executing algorithm calculation of optical fiber differential protection function and logical judgment of protection action, executing control logic and decision in feeder automation function, including master station centralized FA and local FA automation, processing protocol processing and data interaction in communication and management functions, waveform data collection for fault recording function, executing parameter setting and equipment self-diagnosis in debugging and maintenance functions, and executing data management in log, historical data storage and review functions.

3. The integrated measurement, control, communication and data unit for power distribution automation system according to claim 1, characterized in that: The CPU plug-in includes a high-speed 32-bit ARM processor, equipped with a 16-bit high-precision external A / D chip, supports multiple independent network channels and multiple communication protocols, including RS-232, RS-485, Ethernet multiple communication interfaces and IEC60870-5-101 / 104, IEC61850-MMS, IEC61850-GOOSE communication protocols, supports real-time peer-to-peer interactive communication between terminals, and provides 2 Ethernet ports, 1 optical fiber interface, and 2 serial ports.

4. The integrated measurement, control, communication and data unit for power distribution automation system according to claim 1, characterized in that: The analog quantity plug-in includes receiving AC voltage and current analog signals, converting them into digital signals for processing by the CPU plug-in, and providing a data source for the telemetry function.

5. The integrated measurement, control, communication and data unit for power distribution automation system according to claim 1, characterized in that: The analog quantity plug-in includes an analog signal and two DC signals connected from the power distribution system, the analog signal includes a load side voltage, a power supply side voltage and a current signal, and the analog quantity plug-in converts the connected analog signal into a weak current signal suitable for processing by the CPU plug-in; A high-precision external A / D chip is used for AC sampling, and the measured voltage, current, frequency, and calculated active power, reactive power, and power factor parameters are sent to remote transmission. The dead zone range of telemetry collection and upload is set by software; the analog plug-in collects and records short-circuit current, zero-sequence current, and zero-sequence voltage when a feeder fails.

6. The integrated measurement, control, communication and data unit for power distribution automation system according to claim 1, characterized in that: The power output plug-in is connected to the DC24V or DC48V power input with an input range of -20% to +20%, providing stable 24V and 5V DC power supplies for other parts of the terminal, and providing 8-way relay empty node output function. The power output plug-in is responsible for power management and monitoring, including power distribution of the management device and monitoring of the power status; the power output plug-in can use an external isolated power supply instead of the internal 24VDC as the contact input power supply.

7. The integrated measurement, control, communication and data unit for power distribution automation system according to claim 1, characterized in that: The plug-in device collects signals from 16 remote signal hard contacts to provide data for the remote signal function and collects status signals for protection logic judgment. The DC / DC converter inside the plug-in device outputs an isolated 24VDC to provide input loop drive power for the dry contacts, allowing an external isolated power supply to be used instead of the internal 24VDC as the contact input power supply.

8. The integrated measurement, control, communication and data unit for power distribution automation system according to claim 1, characterized in that: The LCD display plug-in includes a 160*160 dot matrix LCD screen. The user interface displays telemetry, telesignaling data, protection and control status. The user checks and sets parameters through the LCD screen.

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