How to calibrate electric energy measurement

Electric energy measurement is an important link in the operation and management of power system, which is widely used in industry, commerce and residential electricity consumption. Accurate electric energy measurement is not only related to the economic benefits of electric power enterprises, but also affects the electricity cost of users. Therefore, it is of great practical significance to calibrate the watt-hour meter regularly to ensure its measurement accuracy.

First, the basic principle of electric energy measurement

Electric energy meter, also known as watt-hour meter, is an instrument used to measure electric energy. Its basic working principle is that the current and voltage in the circuit are induced by the current coil and the voltage coil, and the aluminum disk is driven to rotate by the electromagnetic induction principle, or the signal is converted into digital display in the electronic watt-hour meter. The unit of measurement of electric energy is usually kWh.

Second, the significance of electric energy measurement and calibration

In the process of long-term use, the measurement error may increase due to mechanical wear, aging of electronic components or environmental factors (such as temperature and humidity). The calibration of electric energy measurement is to check whether the actual measured value of electric energy meter is within the allowable error range by comparing with the standard instrument to ensure its accuracy.

Calibration is not only a test of the performance of watt-hour meters, but also the basis for ensuring fair trade in the power market. For power companies, accurate measurement helps to prevent power loss; For users, it can ensure the reasonable charge of electricity.

Third, the method of electric energy measurement and calibration

1. Laboratory calibration
The laboratory calibration is carried out in the standard test environment, using the standard electric energy meter as a reference, and connecting the same load circuit with the calibrated meter at the same time, and comparing the differences between the measured values. This method has high accuracy and is suitable for the first verification and periodic inspection of newly installed electric energy meters.

2. Field calibration
On-site calibration refers to testing the electric energy meter at the actual installation site. The actual voltage, current and power are measured by connecting the portable multifunctional electric energy calibrator to the circuit, and then compared with the displayed value of the electric energy meter to judge whether the error is within the allowable range. Field calibration has the characteristics of flexible operation and high efficiency, and is suitable for periodic calibration of large-scale in-use meters.

3. Remote online monitoring and calibration technology
With the development of smart grid, more and more smart meters have the function of remote communication. By collecting meter data and uploading it to the background system, combined with big data analysis, error evaluation and anomaly detection are carried out. Although it can not completely replace the traditional calibration at present, it has become an important trend of energy metering management in the future.

IV. Calibration Period and Standard Specification

According to relevant national standards (such as JJG 596 Verification Regulation of Electronic Watt-hour Meter), different types of watt-hour meters have clear verification cycle requirements. For example, the verification period of AC watt-hour meters used for trade settlement is generally 2 years, while the period of high-voltage watt-hour meters in operation is shorter. Calibration should be based on the national metrological verification regulations, using certified standard equipment and operated by qualified professionals.

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With the intelligent and digital development of power system, the technology of electric energy measurement and calibration is also improving. From traditional manual calibration to modern intelligent remote monitoring, accurate measurement has become an important support for power management. Scientific and standardized calibration of electric energy meters can not only improve the management level of electric power enterprises, but also help to build a fair and just electricity market environment. Therefore, strengthening the attention to the calibration of electric energy measurement is one of the key measures to ensure the accuracy of energy measurement and promote energy conservation and emission reduction.