Interview with China Academy of Metrology Science Lu Zuliang

The national electric energy meter verification procedures have made clear restrictions on the verification conditions, and the experiments are conducted under the steady-state conditions of the laboratory. The type evaluation syllabus used for calibrating the watt-hour meter and the domestic and foreign standards of the watt-hour meter include some harmonic experiments, but the dynamic characteristics of the watt-hour meter need to be emphasized.

[TC104] In recent years, you have been working on the research of the dynamic characteristics experiment of the electric energy meter. Can you tell us why you chose this topic?

[Lu Zuliang] The issue of dynamic load has long attracted attention, such as electric locomotives and rolling mills. However, in the past, the focus was on the treatment of harmonics, and now the discussion of dynamic functions covers the purpose of accurately measuring electrical energy.

In order to meet the needs of low-carbon and green development, energy sources such as solar cells and electric devices such as electric vehicles will be introduced into the power grid. The resulting current is often not steady-state but presents a transitional process. Although electronic devices that ease this state will certainly appear, the demand for the dynamic measurement function of the energy meter is an inevitable trend. Similar problems have attracted the attention of electric energy meter manufacturers and power scientific research units. Some have begun to study power meters with dynamic functions and corresponding calibration equipment.

The smart grid is an important task in the current national economy and has been under development for several years. The smart meter will add functionality to the original meter. I think dynamic measurement is one of the important new features. Dynamic measurement is an important part of AMI. From these perspectives, this issue requires in-depth study.

[TC104 Network] Please tell us about the research trend of the internationalization of this topic?

[Lu Zuliang] Currently, the IEC standards, international recommendations, national standards, and national verification regulations for electric energy meters are all specified for the performance test of electric energy meters under stable conditions. Verification or calibration of a watt-hour meter under dynamic conditions is a completely new problem. However, related issues have been discussed.

In 2010, we raised this issue at the International Conference on Precision Electromagnetic Measurement, and made preliminary suggestions that have attracted the attention of international counterparts. At present, some internationally renowned instrument manufacturers are developing related standard instruments with reference to our ideas. It is estimated that such products will be introduced soon.

[TC104 network] After painstaking experiment, what did you find?

[Lu Zuliang] I think that the resolution of this issue requires many efforts. For example, the operating unit of the electric power provides the actual situation or typical situation of the dynamic current of the electric network. The electric energy meter manufacturer develops the electric energy meter with dynamic function, and the instrument manufacturer provides the calibration equipment that meets the requirements. We are looking at the dynamic measurement function of the energy meter to see if it is truly (or accurately) measuring the energy under dynamic conditions. Specifically, it is hoped to guide, improve, and standardize the quality of a new generation of electric energy meter by proposing a test method that satisfies the dynamic measurement function. In this process, we need to combine our measurement capabilities to continuously deepen our understanding of this issue. With reference to the actual situation of the actual application department and the electric energy meter manufacturing company, we will continue to explore through continuous experimentation in constant discussions with various experts. Improve this test method.

[TC104 Network] At present, what is your progress in scientific research?

Director Lu Zuliang: Leaders at all levels of the China Institute of Metrology attach great importance to this work. Several years ago, they began to allocate funds and set up research topics.

With the assistance of instrument manufacturers, we have developed a power source with dynamic current output, and collected a variety of currently used power meters, including single-phase and three-phase, electrical gateways, and home-use, electronic ones. And inductive, imported and domestic. Then test these tables, initially found some problems, and proposed solutions. Research results have been published in the "Electrical Measurement and Instrumentation" magazine.

At present, the first phase of the work has been completed and the next phase of research is being planned. We are prepared to publish the achievements we have made and our thinking in international conferences in order to obtain opinions and suggestions from international colleagues and avoid possible one-sidedness.

Also participating in this work were Li Min Senior Engineer and Wang Lei Researcher of the China Academy of Metrology Science, Zhu Chinese Researcher and Zheng Jianzhong Engineer of the Zhejiang Institute of Metrology, and Dr. Eddy So ​​from NRC, National Institute of Metrology, Canada. After researching, he listened to his opinions.