Disclosure of Invention
In view of this, the embodiment of the invention provides an online evaluation method for metering accuracy of a voltage transformer and a terminal device, so as to solve the problems that in the prior art, due to the fact that CVT physical characteristics enable error electric quantity to be continuously enlarged in a detection period, fairness and accuracy of electric quantity transaction are affected, and serious conditions even threaten safe operation of a power grid.
The first aspect of the embodiment of the invention provides an online evaluation method for the metering accuracy of a voltage transformer, which comprises the following steps:
acquiring gateway data acquired by a data acquisition system;
acquiring standard gateway data stored by a comprehensive test management platform;
and determining the capacitance, the dielectric loss and the parameter variation trend of the corresponding line loss of the voltage transformer according to the gateway data and the standard gateway data, and determining the metering accuracy of the voltage transformer according to the capacitance, the dielectric loss and the parameter variation trend of the corresponding line loss.
As a further technical solution, the method further comprises:
the line loss rate expression of the line loss between the metering gateway of the voltage transformer and the reference point is as follows:
r'=r-f1+f2wherein r' is the line loss rate displayed by the acquisition system, r is the actual line loss rate of the line, f1Is the ratio difference between the measuring point and the voltage transformer, f2Is the ratio difference between the reference point and the voltage transformer.
As a further technical scheme, the voltage transformer comprises a capacitance voltage division unit and an electromagnetic unit, wherein the capacitance voltage division unit comprises parallel membrane paper composite media or parallel full-membrane media.
As a further technical scheme, the influence of the insulation structure of the voltage transformer on the metering performance comprises the inner insulation performance, the outer insulation performance and the aging performance.
As a further technical solution, the method further comprises:
judging whether the metering accuracy of the voltage transformer is qualified or not according to a prestored accuracy judgment standard;
and if the metering accuracy of the voltage transformer is judged to be unqualified, sending an alarm instruction to an alarm device, wherein the alarm instruction is used for indicating the alarm device to alarm.
A second aspect of the embodiments of the present invention provides an online evaluation apparatus for measurement accuracy of a voltage transformer, including:
the gateway data acquisition module is used for acquiring gateway data acquired by the data acquisition system;
the standard gateway data acquisition module is used for acquiring standard gateway data stored by the comprehensive test management platform;
and the measurement accuracy determining module is used for determining the capacitance, the dielectric loss and the parameter change trend of the corresponding line loss of the voltage transformer according to the gateway data and the standard gateway data, and determining the measurement accuracy of the voltage transformer according to the capacitance, the dielectric loss and the parameter change trend of the corresponding line loss of the voltage transformer.
As a further technical solution, the apparatus further includes:
and the line loss rate determining module is used for expressing the line loss rate of the line loss between the metering gateway of the voltage transformer and the reference point as follows:
r'=r-f1+f2wherein r' is the line loss rate displayed by the acquisition system, r is the actual line loss rate of the line, f1Is the ratio difference between the measuring point and the voltage transformer, f2Is the ratio difference between the reference point and the voltage transformer.
As a further technical scheme, the voltage transformer comprises a capacitance voltage division unit and an electromagnetic unit, wherein the capacitance voltage division unit comprises parallel membrane paper composite media or parallel full-membrane media.
A third aspect of the embodiments of the present invention provides a terminal device for online evaluation of metering accuracy of a voltage transformer, including a memory, a processor, and a computer program stored in the memory and executable on the processor, where the processor implements the method according to the first aspect when executing the computer program.
A fourth aspect of embodiments of the present invention provides a computer-readable storage medium having stored thereon a computer program which, when executed by a processor, performs the method according to the first aspect.
Compared with the prior art, the embodiment of the invention has the following beneficial effects: after the scheme is adopted, the capacitance, the dielectric loss and the parameter change trend of the corresponding line loss of the voltage transformer can be determined according to the gateway data and the standard gateway data, the metering accuracy of the voltage transformer is determined according to the capacitance, the dielectric loss and the parameter change trend of the corresponding line loss, the operation and maintenance management level and the reliability of gateway metering are improved, the online state monitoring, the fault diagnosis and the state evaluation of the whole metering gateway equipment (comprising an electric energy meter and a current-voltage transformer) are expanded and realized, and the powerful support is provided for the state detection and the intelligent diagnosis evaluation of the gateway metering.
Detailed Description
In the following description, for purposes of explanation and not limitation, specific details are set forth, such as particular system structures, techniques, etc. in order to provide a thorough understanding of the embodiments of the invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present invention with unnecessary detail.
In order to explain the technical means of the present invention, the following description will be given by way of specific examples.
As shown in fig. 1, a flow chart of steps of an online evaluation method for metering accuracy of a voltage transformer provided in an embodiment of the present invention includes:
and S101, acquiring gateway data acquired by a data acquisition system.
And S102, acquiring standard gateway data stored by the comprehensive test management platform.
And S103, determining the capacitance, the dielectric loss and the parameter variation trend of the corresponding line loss of the voltage transformer according to the gateway data and the standard gateway data, and determining the metering accuracy of the voltage transformer according to the capacitance, the dielectric loss and the parameter variation trend of the corresponding line loss.
Specifically, the scheme is suitable for analyzing related parameters of metering accuracy of a gateway metering capacitor voltage transformer, remote online evaluation and early warning are realized on the accuracy change working condition of a CVT (continuously variable transmission), an evaluation and early warning mechanism replaces an online real-time inspection mode which is difficult to popularize, more than 10 internal and external factor parameter and metering characteristic change relation models are established, a powerful background calculation model base is formed, a system automatically acquires real-time data and test data, the comprehensive error is automatically analyzed, the actual error evaluation value under the standard condition is given, the comprehensive state of the CVT is evaluated, different-level alarms are given to abnormality, and an offline production plan is automatically generated. The assessment system achieves the purposes of improving the operation and maintenance management level and reliability of gateway metering, and simultaneously expands the online state monitoring, fault diagnosis and state assessment of the whole metering gateway equipment including the electric energy meter and the current-voltage transformer, and provides powerful support for the state detection and intelligent diagnosis and assessment of gateway metering.
Further, as shown in fig. 5, in a specific example, the method further includes:
the line loss rate expression of the line loss between the metering gateway of the voltage transformer and the reference point is as follows:
r'=r-f1+f2wherein r' is the line loss rate displayed by the acquisition system, r is the actual line loss rate of the line, f1Is the ratio difference between the measuring point and the voltage transformer, f2Is the ratio difference between the reference point and the voltage transformer.
Specifically, in a specific example, from the system configuration, according to DL/T448-. However, when the measurement accuracy changes, the line loss rate calculated by collecting the background data of the system changes correspondingly.
In addition, in a specific example, the voltage transformer comprises a capacitance voltage division unit and an electromagnetic unit, the capacitance voltage division unit comprises parallel membrane paper composite media or parallel full-membrane media, and a basic electrical schematic diagram of the capacitance voltage division unit is shown in fig. 6.
Further, in one particular example, the effect of the insulation structure of the voltage transformer on the metering performance includes inner insulation performance, outer insulation performance, and aging performance.
In addition, as shown in fig. 7, 8 and 9, in a specific example, the influence of the CVT insulation structure on the measurement performance mainly needs to consider the influence of the internal insulation, the external insulation, aging and temperature and humidity, and the influence of parameters such as leakage current, stray capacitance and power frequency resistance introduced into the device model, where Zm is excitation impedance, Zd is damping impedance, ZL is load impedance, and C in the dielectric parallel connection1Is a CVT high-voltage capacitor, C2For CVT low-voltage capacitance, R1 and R2 represent the comprehensive insulation resistance of the device, C1'、C2' high-voltage and low-voltage integrated capacitors are respectively considered, and influence of factors such as stray capacitance and the like is considered. In the operation process of the CVT, due to the influence of external dirt, temperature and humidity and aging, the reduction of external insulation resistance, the increase of capacitance leakage and the change of capacitance caused by partial breakdown of capacitance can occur.
For an RC parallel model medium, the dielectric loss isWherein, delta is a dielectric loss angle, and when no load exists, the output U is0And USThe relationship is as follows:
Wherein,
for the input-output relationship diagram equivalent to a basic RC circuit, the equivalent R, C is:
for the equipment load, the change influence is ignored, the loop impedance of the electromagnetic unit is ignored, the total equivalent load is ZL', the model is further simplified,
the calculation can obtain:
the output voltage U is dependent on the low-voltage capacitor C2 and its dielectric loss epsilon2Decreases with its high-voltage capacitance C1 and its dielectric loss e1The output voltage U varies with the insulation performance parameter of the equipment, i.e. the measurement accuracy varies with the insulation performance parameter of the equipment.
By integrating the above principles, a gateway metering capacitor voltage transformer metering accuracy remote online early warning system is established based on a cross-professional big data sharing platform, an evaluation early warning module is used as a core, data of an acquisition system and a comprehensive test management platform are used as resources, the operation condition of equipment is monitored in real time, parameter change trends such as CVT capacitance, dielectric loss and corresponding line loss are analyzed, the aging condition of the equipment is periodically evaluated, and the CVT accuracy change degree is pre-judged.
In addition, in a specific example, the method further comprises:
step S201, judging whether the metering accuracy of the voltage transformer is qualified or not according to a prestored accuracy judgment standard.
And S202, if the metering accuracy of the voltage transformer is judged to be unqualified, sending an alarm instruction to an alarm device, wherein the alarm instruction is used for indicating the alarm device to alarm.
As shown in fig. 3, a schematic structural diagram of an online evaluation apparatus for measuring accuracy of a voltage transformer provided in an embodiment of the present invention includes:
a gateway data obtaining module 301, configured to obtain gateway data collected by the data collection system.
And a standard gateway data obtaining module 302, configured to obtain standard gateway data stored by the comprehensive test management platform.
And the measurement accuracy determining module 303 is configured to determine the capacitance, the dielectric loss, and the parameter variation trend of the corresponding line loss of the voltage transformer according to the gateway data and the standard gateway data, and determine the measurement accuracy of the voltage transformer according to the capacitance, the dielectric loss, and the parameter variation trend of the corresponding line loss of the voltage transformer.
Further, in one particular example, the apparatus further comprises:
and the line loss rate determining module is used for expressing the line loss rate of the line loss between the metering gateway of the voltage transformer and the reference point as follows:
r'=r-f1+f2wherein r' is the line loss rate displayed by the acquisition system, r is the actual line loss rate of the line, f1Is the ratio difference between the measuring point and the voltage transformer, f2Is the ratio difference between the reference point and the voltage transformer.
In addition, in a specific case, the voltage transformer comprises a capacitance voltage division unit and an electromagnetic unit, wherein the capacitance voltage division unit comprises parallel membrane paper composite media or parallel full-membrane media.
Further, in one particular example, the effect of the insulation structure of the voltage transformer on the metering performance includes inner insulation performance, outer insulation performance, and aging performance.
Further, in one particular example, the apparatus further comprises:
and judging whether the metering accuracy of the voltage transformer is qualified or not according to a prestored accuracy judgment standard.
And if the metering accuracy of the voltage transformer is judged to be unqualified, sending an alarm instruction to an alarm device, wherein the alarm instruction is used for indicating the alarm device to alarm.
Specifically, a qualified value interval of the accuracy is recorded in the pre-stored accuracy judgment standard, if the metering accuracy of the voltage transformer is judged not to be in the qualified interval, the metering accuracy of the voltage transformer is judged to be unqualified, and an alarm instruction is sent to an alarm device to remind a worker to process the voltage transformer in time. The alarm type can be one or more of voice alarm, vibration alarm, buzzing alarm or information prompt alarm type.
In a specific case, independent models of the gateway CVTs are established, the accuracy change degree of the equipment is calculated by means of the change condition of high-voltage test parameters, and a comprehensive theoretical error is given. Based on a gateway acquisition system platform, the line loss data variation of the corresponding line of the CVT is used for verifying the theoretical error variation condition, comprehensively judging whether the CVT is abnormal or not, and early warning the abnormal variation trend. A relation model of a primary test parameter and a secondary metering accuracy test parameter of the CVT is established by a CVT physical model under several typical environmental factors. And the multi-characterization factor collaborative analysis under the big data can be used for widely and deeply mining a large amount of data of the power utilization information acquisition system and the comprehensive test data platform, and organically combining the comprehensive analysis. According to the multichannel data synchronous acquisition method, a CVT metering performance online monitoring system needs to acquire a plurality of CVT sampling values at intervals in a transformer substation, so that the synchronization of the acquired data among a plurality of electric quantities is realized, the synchronous delay error is ensured to be less than 10us, and the synchronism and effectiveness of data are ensured. The comprehensive evaluation method is developed on the basis of a model and various evaluation means, overall judgment is made on CVT metering characteristics, the method is synergistic, two methods of test parameter association and online line loss analysis are jointly evaluated and verified, and the reliability of the method is greatly improved. And establishing a relation model of the CVT high-voltage test parameter and the measurement accuracy test parameter. And (3) applying and mining cross-professional test data, fully utilizing the characteristic that the high-voltage test period is relatively short, establishing a primary parameter relation and a secondary parameter relation of equipment, and making up the defect of long test period of metering accuracy in an online comprehensive evaluation mode. And combining the offline test data with the online real-time electric quantity data to realize the deep application of the related data. The online evaluation of the metering performance of the CVT is achieved, the operation comprehensive error measurement and calculation under the actual state of the whole electric energy metering device are simultaneously achieved, the online state monitoring, the fault diagnosis and the state evaluation of the whole metering gateway equipment (comprising an electric energy meter and a current-voltage transformer) are achieved, the powerful support is provided for the state detection and the intelligent diagnosis evaluation of the gateway metering, compared with the current online verification mode, the online evaluation method is low in investment cost, and has better development prospect and space under the background of big data application.
It should be understood that, the sequence numbers of the steps in the foregoing embodiments do not imply an execution sequence, and the execution sequence of each process should be determined by its function and inherent logic, and should not constitute any limitation to the implementation process of the embodiments of the present invention.
Fig. 4 is a schematic diagram of a terminal device for online evaluation of metering accuracy of a voltage transformer according to an embodiment of the present invention, where the terminal device 4 of the embodiment includes: a processor 40, a memory 41 and a computer program 42, such as a voltage transformer metering accuracy on-line evaluation program, stored in said memory 41 and executable on said processor 40. The processor 40, when executing the computer program 42, implements the steps in the various embodiments of the method described above, such as the steps 101 to 103 shown in fig. 1. Alternatively, the processor 40, when executing the computer program 42, implements the functions of each module/unit in each device embodiment described above, for example, the functions of the modules 301 to 303 shown in fig. 3.
Illustratively, the computer program 42 may be partitioned into one or more modules/units that are stored in the memory 41 and executed by the processor 40 to implement the present invention. The one or more modules/units may be a series of computer program instruction segments capable of performing specific functions, and the instruction segments are used for describing the execution process of the computer program 42 in the voltage transformer metering accuracy online evaluation terminal device 4. For example, the computer program 42 may be divided into a synchronization module, a summary module, an acquisition module, and a return module (a module in a virtual device), and each module has the following specific functions:
and acquiring gateway data acquired by the data acquisition system.
And acquiring standard gateway data stored by the comprehensive test management platform.
And determining the capacitance, the dielectric loss and the parameter variation trend of the corresponding line loss of the voltage transformer according to the gateway data and the standard gateway data, and determining the metering accuracy of the voltage transformer according to the capacitance, the dielectric loss and the parameter variation trend of the corresponding line loss.
The line loss rate expression of the line loss between the metering gateway of the voltage transformer and the reference point is as follows:
r'=r-f1+f2wherein r' is the line loss rate displayed by the acquisition system, r is the actual line loss rate of the line, f1Is the ratio difference between the measuring point and the voltage transformer, f2Is the ratio difference between the reference point and the voltage transformer.
The voltage transformer comprises a capacitor voltage division unit and an electromagnetic unit, wherein the capacitor voltage division unit comprises parallel membrane paper composite media or parallel full-membrane media.
The influence of the insulation structure of the voltage transformer on the metering performance comprises the inner insulation performance, the outer insulation performance and the aging performance.
And judging whether the metering accuracy of the voltage transformer is qualified or not according to a prestored accuracy judgment standard.
And if the metering accuracy of the voltage transformer is judged to be unqualified, sending an alarm instruction to an alarm device, wherein the alarm instruction is used for indicating the alarm device to alarm.
The terminal device 4 for online evaluation of the metering accuracy of the voltage transformer can be a desktop computer, a notebook, a palm computer, a cloud server and other computing devices. The terminal equipment for online evaluation of the metering accuracy of the voltage transformer can comprise, but is not limited to, a processor 40 and a memory 41. Those skilled in the art will understand that fig. 4 is only an example of the terminal device 4 for online evaluation of the metering accuracy of the voltage transformer, and does not constitute a limitation of the terminal device 4 for online evaluation of the metering accuracy of the voltage transformer, and may include more or less components than those shown in the drawings, or combine some components, or different components, for example, the terminal device for online evaluation of the metering accuracy of the voltage transformer may further include an input-output device, a network access device, a bus, and the like.
The Processor 40 may be a Central Processing Unit (CPU), other general purpose Processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), an off-the-shelf Programmable Gate Array (FPGA) or other Programmable logic device, discrete Gate or transistor logic, discrete hardware components, etc. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like.
The memory 41 may be an internal storage unit of the voltage transformer metering accuracy online evaluation terminal device 4, for example, a hard disk or a memory of the voltage transformer metering accuracy online evaluation terminal device 4. The memory 41 may also be an external storage device of the voltage transformer metering accuracy online evaluation terminal device 4, for example, a plug-in hard disk, a Smart Media Card (SMC), a Secure Digital (SD) Card, a Flash memory Card (Flash Card), or the like, which is equipped on the voltage transformer metering accuracy online evaluation terminal device 4. Further, the memory 41 may also include both an internal storage unit and an external storage device of the online evaluation terminal device 4 for the metering accuracy of the voltage transformer. The memory 41 is used for storing the computer program and other programs and data required by the online evaluation terminal equipment of the metering accuracy of the voltage transformer. The memory 41 may also be used to temporarily store data that has been output or is to be output.
It will be apparent to those skilled in the art that, for convenience and brevity of description, only the above-mentioned division of the functional units and modules is illustrated, and in practical applications, the above-mentioned function distribution may be performed by different functional units and modules according to needs, that is, the internal structure of the apparatus is divided into different functional units or modules to perform all or part of the above-mentioned functions. Each functional unit and module in the embodiments may be integrated in one processing unit, or each unit may exist alone physically, or two or more units are integrated in one unit, and the integrated unit may be implemented in a form of hardware, or in a form of software functional unit. In addition, specific names of the functional units and modules are only for convenience of distinguishing from each other, and are not used for limiting the protection scope of the present application. The specific working processes of the units and modules in the system may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.
In the above embodiments, the descriptions of the respective embodiments have respective emphasis, and reference may be made to the related descriptions of other embodiments for parts that are not described or illustrated in a certain embodiment.
Those of ordinary skill in the art will appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.
In the embodiments provided in the present invention, it should be understood that the disclosed apparatus/terminal device and method may be implemented in other ways. For example, the above-described embodiments of the apparatus/terminal device are merely illustrative, and for example, the division of the modules or units is only one logical division, and there may be other divisions when actually implemented, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may be in an electrical, mechanical or other form.
The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.
In addition, functional units in the embodiments of the present invention may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit. The integrated unit can be realized in a form of hardware, and can also be realized in a form of a software functional unit.
The integrated modules/units, if implemented in the form of software functional units and sold or used as separate products, may be stored in a computer readable storage medium. Based on such understanding, all or part of the flow of the method according to the embodiments of the present invention may also be implemented by a computer program, which may be stored in a computer-readable storage medium, and when the computer program is executed by a processor, the steps of the method embodiments may be implemented. Wherein the computer program comprises computer program code, which may be in the form of source code, object code, an executable file or some intermediate form, etc. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, usb disk, removable hard disk, magnetic disk, optical disk, computer Memory, Read-Only Memory (ROM), Random Access Memory (RAM), electrical carrier wave signals, telecommunications signals, software distribution medium, and the like. It should be noted that the computer readable medium may contain other components which may be suitably increased or decreased as required by legislation and patent practice in jurisdictions, for example, in some jurisdictions, computer readable media which may not include electrical carrier signals and telecommunications signals in accordance with legislation and patent practice.
The above-mentioned embodiments are only used for illustrating the technical solutions of the present invention, and not for limiting the same; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not substantially depart from the spirit and scope of the embodiments of the present invention, and are intended to be included within the scope of the present invention.