Abstract: DL/T 731-2000 is a key industry standard in China’s power sector, specifically formulated for error calculators applied in electrical energy meter calibrating. This standard defines the technical requirements, test methods, inspection rules, marking, packaging, and storage requirements for such calculators, serving as the authoritative technical basis for the use, testing, and acceptance of error calculators by power metering departments and manufacturers. This article elaborates on the core content of DL/T 731-2000, analyzes its technical characteristics and application value, and discusses its role and significance in ensuring the accuracy and reliability of electrical energy measurement.

1. Introduction

Electrical energy measurement is a crucial link in the power industry, directly related to the fair trade of electrical energy and the stable operation of the power system. Error calculators used in electrical energy meter calibrating are core supporting equipment of electrical energy metering standard devices, whose performance and accuracy directly affect the calibration results of electrical energy meters. To standardize the technical indicators and application of such equipment, the State Economic and Trade Commission of the People’s Republic of China issued the industry standard DL/T 731-2000 “Error Calculator Used in Electrical Energy Meter Calibrating” on November 3, 2000, which was officially implemented on January 1, 2001 . This standard integrates relevant national and machinery industry standards and combines the characteristics of electrical energy metering work in the power industry, filling the gap in the technical standardization of error calculators in China’s power sector.

DL/T 731-2000 was proposed by the former Ministry of Electric Power Industry, standardized by the Power Industry Electrical Measurement Standardization Technical Committee, and drafted by East China Electric Power Test & Research Institute, Haiyan Electric Power Instrument Factory, and Yangcheng Technology Industrial Company . The standard has strong pertinence and operability, providing clear technical guidance for the research and development, production, and application of error calculators.

2. Scope of Application

DL/T 731-2000 specifies the technical requirements, test methods, and inspection rules for error calculators used in electrical energy meters . The standard is applicable to error calculators that adopt pulse input mode, use computer operation and processing, and display relative error values. In addition, electronic standard energy meters with error calculation functions and capable of displaying the relative error of energy meters, error calculation parts in energy meter verification devices, and on-site calibrators can also refer to this standard .

It should be noted that the application of this standard covers both laboratory verification and on-site calibration scenarios, which is of great significance for ensuring the consistency and accuracy of energy meter calibration results in different application environments . Meanwhile, as an important part of the power industry’s standard system, DL/T 731-2000 is closely linked with other relevant standards (such as GB/T 11150, JJG 597, etc.), forming a complete technical standard system for electrical energy measurement .

3. Core Technical Requirements

The technical requirements specified in DL/T 731-2000 are the core content of the standard, covering basic functions, input interfaces, DC power output, power consumption, insulation performance, climate resistance, electrostatic discharge immunity, and other aspects.

3.1 Basic Functions

3.1.1 Parameter Presetting: According to the requirements of different error calculation categories, the error calculator shall be able to arbitrarily set the number of revolutions or pulses of the energy meter, or the preset range and bit value of the energy meter constant or energy meter constant ratio, which shall meet the relevant provisions in the energy meter verification method . This ensures that the error calculator can adapt to the calibration needs of different types and specifications of energy meters.

3.1.2 Inspection Load Point Selection: The standard specifies that the inspection load points should preferably be 0.01, 0.02, 0.05, 0.1, 0.2, 0.5, 1, 2, 4, 6, 8, and 10 times the basic current (I) . This selection of load points covers the common working conditions of energy meters, ensuring the comprehensiveness and accuracy of error measurement.

3.2 Input Interface

The input interface requirements of the error calculator are clearly defined in the standard: (a) The standard pulse signal input terminal shall be able to accept pulse signals not less than 150 kHz, and the tested pulse signal input terminal shall also be able to accept pulse signals not less than 15 Hz; (b) The low level of the pulse signal is (0-0.6) V, the high level is (3.5-24) V, the input impedance shall be greater than 10 kΩ, and the interface shall be able to accept passive pulse signals . These requirements ensure the reliability and stability of pulse signal transmission, laying a foundation for accurate error calculation.

3.3 DC Power Output

For external photoelectric samplers, the error calculator can provide DC regulated power supply output. When the nominal voltage of each output is 5V, the output voltage value shall be within ±5% of the nominal value, the output power shall not be less than 2W, and the output voltage stability shall be less than 0.5% within 30 minutes . This ensures that the external photoelectric sampling equipment can work stably, further guaranteeing the accuracy of sampling signals.

3.4 Other Key Technical Requirements

Power Consumption: Under the conditions of nominal input voltage of 220V and frequency of 50Hz, the power consumption of the error calculator when not providing DC power output shall not be greater than 15VA (when each output terminal with external power supply is connected to a 2W load, the power consumption can be increased by 5VA) .

Insulation Performance: The error calculator shall be able to withstand the insulation resistance and AC voltage tests specified in Clause 6.8 of this standard, and no arc discharge or breakdown shall occur during the test .

Climate Resistance: It shall withstand high temperature (70±2)°C for 72 hours in non-working state, low temperature (-25±2)°C for 72 hours, and 6 cycles of alternating damp and heat test under the condition of applying reference working voltage without special measures to remove moisture. No component damage affecting normal work shall occur after the tests .

Electrostatic Discharge Immunity: The design of the error calculator shall ensure that no damage to the error calculator or substantial impact on it occurs under electrostatic discharge conditions .

Power Supply Adaptability: The error calculator shall work normally when the working power supply is within ±15% of the nominal voltage value and ±5% of the nominal frequency value .

Temperature Rise: Under the condition that the ambient temperature does not exceed 40°C, the temperature rise at any point on the surface of the error calculator shall be less than 25K .

4. Test Methods and Inspection Rules

DL/T 731-2000 specifies detailed test methods for each technical requirement, including test equipment, test procedures, and data processing methods. For example, in the test of DC power output performance, it is necessary to use a precision voltage meter to measure the output voltage under different load conditions and calculate the voltage stability; in the insulation performance test, it is necessary to use an insulation resistance tester and an AC voltage tester to carry out corresponding tests .

The inspection rules of the standard include type inspection and routine inspection. Type inspection shall be carried out when new products are put into production, product design is modified, raw materials or processes are greatly changed, or when the product is re-produced after being out of production for a long time. Routine inspection shall be carried out on each product leaving the factory . The items, qualified criteria, and sampling methods of the two types of inspections are clearly defined, ensuring that the quality of error calculators meets the standard requirements.

5. Marking, Packaging and Storage

The standard requires that the error calculator shall be marked with the product name, model, standard number (DL/T 731-2000), manufacturer’s name, production date, and serial number . For packaging, the product shall be packaged in appropriate packaging materials to prevent damage during transportation and storage. The packaging shall also be marked with the product name, model, quantity, manufacturer’s name, and transportation warning signs .

In terms of storage, the error calculator shall be stored in a dry, ventilated, and clean warehouse, away from sources of heat, moisture, and corrosion. The storage temperature shall be between -10°C and 40°C, and the relative humidity shall not exceed 80% . These requirements ensure the integrity and performance stability of the product during transportation and storage.

6. Application Value and Industry Significance

DL/T 731-2000 plays an important role in standardizing the technical indicators of error calculators and improving the level of electrical energy measurement in China. Firstly, this standard provides a unified technical basis for power metering departments and manufacturers, ensuring the consistency and comparability of error calculator products. Secondly, the strict technical requirements specified in the standard help to improve the accuracy and reliability of error calculators, thereby ensuring the fairness and accuracy of electrical energy trade .

In addition, with the continuous development of the power industry, especially the construction of smart grids and the large-scale access of new energy, the requirements for electrical energy measurement are getting higher and higher . DL/T 731-2000, as the basic standard for error calculators, provides technical support for the upgrading and intelligent development of electrical energy metering equipment. It also lays a foundation for the formulation and revision of subsequent related standards, promoting the continuous progress of electrical energy measurement technology in China .

In practical applications, many power companies and equipment manufacturers have adopted DL/T 731-2000 as the main basis for product research and development, production, and acceptance. For example, in the technical conditions for ordering and accepting three-phase AC energy meter verification devices of Guangdong Power Grid Corporation, DL/T 731-2000 is clearly listed as a referenced standard . This fully reflects the important position and wide application of this standard in the power industry.

DL/T 731-2000 is an important technical standard in China’s power industry, which comprehensively and systematically regulates the technical requirements, test methods, and application specifications of error calculators used in electrical energy meter calibrating. This standard not only ensures the quality and performance of error calculators but also provides a strong guarantee for the accuracy and reliability of electrical energy measurement, promoting the healthy development of the power industry. With the continuous advancement of power system reform and technological innovation, the application scenario of DL/T 731-2000 will be more extensive, and its role in ensuring the stable operation of the power system and fair trade of electrical energy will be more prominent. In the future, with the development of new technologies such as digitalization and intelligence, it is necessary to further research and revise the standard to adapt to the new requirements of the power industry for electrical energy measurement.

References

[1] DL/T 731-2000, Error Calculator Used in Electrical Energy Meter Calibrating[S]. State Economic and Trade Commission of the People’s Republic of China, 2000.

[2] Panorama of Technical Evolution, Core Deconstruction and Future Application of DL/T 731-2000 “Error Calculator Used in Electrical Energy Meter Calibrating”[P]. 2026.

[3] Guangdong Power Grid Corporation. Technical Conditions for Ordering and Accepting Three-Phase AC Energy Meter Verification Devices[S].

[4] Analysis and Testing Encyclopedia Network. Standards for Measurement Relative Error[EB/OL]. 2025.

[5] CSDN Blog. Input Voltage Overvoltage Protection Value and Undervoltage Protection Value of Three-Phase 380V[EB/OL]. 2025.

[6] Standard Library. Industry Standard Filing Announcement (No. 12, 2000)[EB/OL].