Bài viết trình bày một giải pháp để loại bỏ ảnh hưởng đó và đề xuất một mô hình thiết bị đo và giám sát điện trở cách điện. Kết quả nghiên cứu này có thể áp dụng trong việc thiết kế, chế tạo các thiết bị đo và giám sát tự động điện trở cách điện các mạng hỗn hợp xoay chiều/một chiều cách ly. | 80 Journal of Mining and Earth Sciences Vol. 63 Issue 2 2022 80 - 88 Measurement and automatic monitoring insulation resistance of AC DC mixed unearthed networks Anh Cam Thi Kim 1 Giang Truong Nguyen 1 Sy Tien Nguyen 1 Quan Van Nguyen 2 1Faculty of Electro-Mechanical Hanoi University of Mining and Geology Vietnam 2The Office of National Science and Technology Research Programs Ministry of Science and Technology Vietnam ARTICLE INFO ABSTRACT Article history Where the danger of electric shock is high for example underground Received 15th Aug. 2021 mines or medical equipment directly connected to a patient special Accepted 2nd Jan. 2022 ungrounded power systems unearthed networks may be used to Available online 30th Apr. 2022 minimize possible leakage current to the ground. In mixed unearthed Keywords networks AC DC-IT comprising alternating and direct current Automatic monitoring circuits AC part of system is connected with DC part through rectifyer Diode rectifier valves. Commutation of the valves causes cyclic variation of configuration of the entire galvanically connected network. A distinct Insulation resistive feature of AC DC-IT systems is that voltages between all points of AC side Unearthed network. and ground may have mean value different from zero. This characteristic parameter can be used as a signal to determine fault and position to ground or decrease in insulation resistance. However it also affects the results of the network equivalent insulation resistance measurements when a DC source is used to check insulation. The paper presents a solution to eliminate this effect and proposes a device model to measure and monitor insulation resistance. The results of this study can be applied in the design and manufacture of automatic resistance measuring and monitoring devices for AC DC mixed unearthed networks. Copyright 2022 Hanoi University of Mining and Geology. All rights reserved. _ Corresponding author E - mail kimthicamanh@ DOI .
