Measuring method for energy metering error of single-phase electric energy meter under dynamic load

Abstract

The invention provides a measuring method for energy metering error of a single-phase electric energy meter under dynamic load. The method comprises the following steps of: timing from the rotation of N cycles of the electric energy meter to be measured; collecting load current Ii by one time in every timing cycle Deltat; accumulating collecting time S-1 and accumulating load current (test I); ending the rotation of N cycles of the electric energy meter to be measured, collecting the current load current Is, obtaining timing time T and calculating the current timing interval by the formula Delta1=T-(S-1)*Deltat; calculating the accumulated energy (test II); setting that actual energy Er passing the electric energy meter to be measured is equal to the accumulated energy EO; and calculating error by the formula r=(EX-Er) / Er=(EX-EO) / EO. By measuring the changing load current continuously, the method avoids the influence of change of the load current to the energy metering error, thus greatly improving the accuracy of measuring the energy metering error.

Description

technical field [0001] The invention relates to a method for measuring an electric energy metering error, in particular to a method for measuring an electric energy metering error of a single-phase electric energy meter under a dynamic load. Background technique [0002] Single-phase electric energy meters are widely used in thousands of households as electric energy metering and billing instruments; single-phase electric energy meters work on the installation site for a long time, in order to ensure accurate measurement of electric energy, it is necessary to carry out on-site calibration and inspection of electric energy meters, measure Whether the energy measurement error meets the requirements, and at the same time judge whether there is electricity theft. [0003] At present, there are mainly two methods for measuring the energy measurement error of the electric energy meter: [0004] 1. Use the field calibrator of the electric energy meter to directly measure and displ...

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Problems solved by technology

[0007] Although the error measurement method using the field calibrator of the electric energy meter has the advantages of high measurement accuracy and direct error measurement, it can be used in occasions where the number of electric energy meters to be tested is large and the measurement accuracy is not high, such as business census, feedback In the case of electric stealing screening, etc., there are the following problems and deficiencies: a. When measuring errors, the on-site calibrator must be connected to the voltage circuit of the meter under test, but it is difficult to reliably connect to the voltage circuit in the field. Therefore, the operation is cumbersome, inconvenient, and the work efficiency is low; b. If the voltage circuit is connected on site, there may be dangers such as electric shock and short circuit, and the safety is not high

[0018] When this method is used to measure the error of electric energy measurement, it has the advantage of not needing to measure the line voltage U at the same time, but it has the following disadvantages: a. The test process requires more than two test tools, and manual calculation is also required. The test process is cumbersome and the work efficiency is low; b. . Due to the excessive manual participation in the measurement process, the possibility of measurement errors is greater; c. The calculation formula is more complicated, and it is difficult for personnel without a certain theoretical basis or non-professionals to master and use it, such as: agricultural electricians; d. Especially when When the load current changes greatly during the measurement period, the measurement accuracy of the error is poor

[0026] Combine below figure 1 To illustrate the situation that the load current I changes: U×It×cosφ is the electric energy passing through the electric energy meter measured by the inspection instrument in the time interval T under the condition that U, I (I=It), and cosφ are constant, which is figure 1 The rectangular area formed by ABt2t1 in , but during T, the actual electric energy passing through the electric energy meter is figure 1 The shaded area Act2t1 in , it can be seen from the figure that the actual electric energy passing through the electric energy meter is very different from the electric energy measured by the tester using the steady-state load method, so there will be measurement method errors

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