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Digital metering system, the electronic energy meter analog-to-digital conversion sampling function moved to the electronic instrument transformer, and electronic instrument transformer sampling frequency compared with the electronic energy meter is low, the sampling frequency will be insufficient in the analog-to-digital conversion process Introduce quantization error. In this paper, the measurement error model of electronic instrument transformer based on analog-to-digital conversion sampling principle is established, and the influence of sampling frequency on energy measurement error is quantitatively analyzed. The analysis shows that the accuracy of electronic instrument transformer measurement is related to oversampling rate.

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A microgrid cluster is composed of multiple interconnected microgrids and operates in the form of cluster, which can realize energy complementation between microgrids and significantly improve their renewable energy consumption capacity and system operation reliability. A microgrid optimal dispatch based on a distributed economic model predictive control algorithm is proposed in this paper. Firstly, the control task of the microgrid power generation system is defined, which is required to meet the load demand while reducing the economic loss of the system and realize dynamic economic optimization. The global objective function is designed based on the control task, and the detailed design method of the distributed economic model predictive controller is given. The control law is obtained by an iterative calculation using the Nash optimal method, which can effectively reduce the amount of data in the communication network. Finally, a microgrid group composed of four microgrids is used as an example for simulation verification. The simulation results show that the distributed economic model predictive control algorithm proposed in this paper has good economic benefits for microgrid dispatching.

The accuracy of electronic voltage transformer (EVT) can be influenced by the variation of ambient temperature. The influence of ambient temperature on key components of EVTs is studied in this paper. The temperature characteristic of the EVTs' collector, and the influence of temperature compensation technology for the accuracy of EVTs was discussed as well via the error comparison between the traditional voltage transformers and EVTs with temperature compensation technology. Compared with EVT, the accuracy of traditional voltage transformer can be less affected by ambient temperature. According to the experimental results, it was clear that the accuracy of EVTs can be greatly improved by the temperature compensation technology.