CN201993463U - Testing device of digital electric energy meter - Google Patents

Abstract

A digital electric energy meter testing device, the device is composed of a digital signal power source, a standard meter, a switch, an error processing device and a control computer; the control computer of the test device is connected to the digital signal power source and the error processing device through an RS485 bus , the digital signal power source and error processing equipment are uniformly controlled by the control computer; when the test device is working normally, the master software of the main control computer controls the digital signal source, digital standard meter, error processor and other related equipment through the RS485 bus. ; The main station software communicates with the measured meter through the RS485 bus using the standard 645 protocol, and is used to read the measurement data and other parameters of the measured meter. The utility model is suitable for testing and checking the digital electric energy meter.

Description

Digital energy meter detection device

technical field

The utility model relates to a digital electric energy meter protocol conformity detection, which belongs to the technical field of electric power metering.

Background technique

The country is building a smart grid, and the application of digital energy meters will become more and more extensive. Because the digital watt-hour meter receives pure digital signals, there is no error caused by transmission, and the calculation of the digital value of the watt-hour meter will not bring additional errors, and the watt-hour meter will not be affected by temperature and long-term drift, so the digital watt-hour meter is ideal. The operating error in the state is very small, and no detection is required. But in fact, due to the following reasons, it will still bring certain errors to the digital energy meter.

(1) The impact of different sampling points on metering: because digital substations have different numbers of cycle sampling points, it is necessary to consider the influence of the number of sampling points on the measurement of electric energy meters.

(2: Harmonic processing of electric energy metering is realized through FFT analysis, and different sampling points also affect the results of FFT analysis. Therefore, it is necessary to consider the influence of harmonics on digital electric energy meter measurement.

(3): The measurement and quantization coefficients corresponding to various voltage and current specifications are different. The mathematical model of the quantization system is abstracted, and the quantization coefficients are calculated according to the voltage and current ratings. There is no need to modify the program according to different user specifications. However, it is necessary to consider the influence of the rated voltage on the measurement of the digital electric energy meter.

(4): When the digital electric energy meter does not receive the data packet of the merging unit, or the received data information is unreasonable, how to do corresponding fault-tolerant processing, so it is necessary to consider the detection of the fault-tolerant ability of the digital electric energy meter.

It can be seen from the above that digital energy meters need to be tested, but because there is no corresponding verification device, no corresponding test equipment, test methods and inspection devices, these digital energy meters are put into operation without a complete test. and performance cannot be guaranteed. In order to improve the performance, technical indicators and detection technology of digital energy meters, improve product quality, realize full intelligence of substations, and improve the level of power grid operation management and control, the detection problem of digital energy meters must be solved.

Contents of the invention

The purpose of this utility model is: to disclose a kind of verification device that can carry out laboratory and on-site detection on the digital electric energy meter of the low-voltage analog interface, which can detect the digital electric energy meter of the low-voltage analog interface; A verification device for laboratory and on-site testing of digital electric energy meters, and a laboratory and on-site digital electric energy meter testing platform. The number of cycle sampling points of the device can be set arbitrarily from 80-200, and the sampling frequency is adjustable from 4-10k. It can detect the influence of harmonics on the measurement of electric energy meters, and can simulate various on-site actual conditions such as packet loss and channel congestion. The merging unit is used for testing various performances of digital energy meters with digital interfaces.

The detection device of the digital electric energy meter of the utility model is composed of a digital signal power source, a standard meter, a switch, an error processing device and a control computer. The control computer of the detection device is connected with the digital signal power source and the error processing equipment through the RS485 bus, and the digital signal power source and the error processing equipment are uniformly controlled by the control computer; RS485 bus controls the work of digital signal source, digital standard meter, error processor and other related equipment. The master software communicates with the measured meter through the RS485 bus using the standard 645 protocol to read the measurement data and other parameters of the measured meter; after the control computer sets the parameters of the power source, it displays the current parameter value in real time. Detect whether the visual value displayed on the inspected meter is consistent with the set parameters. The control computer saves the detected error data, and can generate reports for export, which is convenient for data analysis.

The device can perform conformity tests of various communication protocols on the digital electric energy meter.

The device can simulate a variety of on-site working conditions to output data frames, and can perform protocol compliance tests such as data frame loss and abnormal data channel status.

The device can detect the influence of harmonics on the measurement of digital electric energy meters.

The beneficial effect of the utility model compared with the prior art is that in the traditional electric energy meter calibration device, the signal source and power amplifier of the analog part are affected by attenuation, zero drift, electromagnetic compatibility and linearity, etc., and the output signal needs to be compensated , the circuit design is complex, the accuracy is limited, and the device accuracy is easily affected by the environment. However, the utility model is applied to the electric energy meter detection device of the digital electric energy metering system. In addition to retaining the standard meter module and the error comparison circuit, the digital synthesis D/A analog conversion module and the power amplifier module required by the traditional electric energy meter verification device are not required. If necessary, the limited switching function is no longer required in the error comparison loop. These removed modules are precisely the source of errors in traditional electric energy meter calibration devices.

In addition, the meter detection device of the digital metering system and the metering system are completely numerical calculations, and the errors caused by algorithms and effective bits are negligible in the entire metering system. As an all-digital device, the possibility of accuracy drift caused by ambient temperature or long-term work no longer exists. The verification of the digital energy meter by the detection device is essentially a test of the transmission bit error rate and the software design of the energy meter.

The utility model is suitable for testing and checking the digital electric energy meter.

Description of drawings

The accompanying drawing is a structural block diagram of the digital electric energy meter detection device of the utility model.

Detailed ways

The specific implementation of the utility model is shown in the structural block diagram of the digital electric energy meter detection device in the accompanying drawing.

The electric energy meter detection device in this embodiment is composed of a digital signal power source, a standard meter, a switch, an error processing device and a control computer. The control computer of the calibration table is connected to the power source and error processing equipment through the RS485 bus, and the control computer controls the power source and error processing equipment in a unified manner. When the inspection device is working normally, the master software of the main control computer controls the digital signal source, digital standard meter, error processor and other related equipment through the RS485 bus. The master station software makes the signal source work in the mode of parameter control by setting the signal source parameters, and outputs the IEC60044-7/8 standard voltage signal that meets the parameter requirements. During the testing process, by adjusting the operating parameters and simulating various test conditions, various tests are performed on the meter under test. The master station software controls the digital meter standard meter to output the high-frequency pulse required by the test, and transmits it to the error processor for subsequent error calculation. The main station software can read the electricity value measured on the digital standard meter within a certain period of time through the RS485 bus interface, and compare it with the electric energy measured by the meter under test. The master software communicates with the measured meter through the RS485 bus using the standard 645 protocol, and is used to read the measurement data and other parameters of the measured meter. After the control computer has set the parameters of the power source, it will display the currently set parameter value in real time, and check whether the displayed value of the tested meter is consistent with the set parameter. The control computer saves the detected error data, and can generate reports for export, which is convenient for data analysis.

(1) Various communication protocol compliance tests can be performed on the digital energy meter

This digital energy meter detection device supports IEC61850-9-1/IEC61850-9-2, IEC60044-7/8 standards, and can simultaneously test the interface with non-traditional transformers (electronic transformers ECT/VT, low power transformers LPVCT) digital energy meter.

This digital energy meter detection device can flexibly configure various parameters of IEC61850-9-1 and IEC61850-9-2 standards, including the number of ASDUs, the number of sampling points, the rated delay time, the format of data frames, etc., to adapt to different testing requirements . The number of cycle sampling points can be set arbitrarily from 80-200, and the sampling frequency can be adjusted from 4-10k. It can simulate various on-site actual situations such as packet loss and channel congestion. Experiments that can be carried out include basic error experiments and data frame loss. Experiments, channel congestion and other IEC61850-9-1, IEC61850-9-2 protocol compliance experiments, abnormal data channel state experiments of data frames, influence quantity experiments of electrical parameters, basic function experiments of meters and other experimental items.

Detect the influence of harmonics on the measurement of digital electric energy meters, and the harmonic processing of electric energy measurement is realized through FFT analysis, and different sampling points also affect the results of FFT analysis.

Through the data relay unit, the data frame output by the digital signal source is divided and transferred to multiple signals for use by multiple meters under test at the same time. Realize the simultaneous verification of multiple meter positions of the digital electric energy meter.

This signal source is constructed based on the mathematical model of the three-phase power system. The parameters of the mathematical formulas used in the mathematical model can be set according to actual needs. By setting parameters to simulate various conditions of power grid operation, and then constructing The signal is sampled and quantized according to a certain sampling rate, and the data quantization method meets the requirements of IEC61850-9-1 and IEC61850-9-2 for the quantification of measurement data. The signal source can construct and output sampled data frames under various parameter conditions.

Claims (1)

1. a digitalized electrical energy meter pick-up unit is characterized in that, described pick-up unit is made up of digital power signal source, standard scale, switch, Error processing equipment and control computer; The control computer of described pick-up unit links to each other with digital power signal source and Error processing equipment by the RS485 bus, unifies control figure signal power source and Error processing equipment by control computer; Main platform software by main control computer during the pick-up unit operate as normal passes through RS485 bus control figure signal source, digital standard table, error processor work; Main platform software adopts 645 agreements of standard to communicate by letter with tested table by the RS485 bus, is used to read the continuous data of tested table.

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