HVDC 가공 송전선로의 최적 도체방식 선정을 위한 전기환경 특성평가에 관한 연구

Abstract

Corona characteristic of conductors depends on the electric field conditions in the immediate vicinity of the conductors. For high voltage direct current transmission lines, in particular, the space charge plays an important role in the electric field distribution. Therefore, the HVDC transmission line conductor configuration needs to consider corona interferences such as radio noise, audible noise and television noise in its design. In addition, the transmission line design requires data that estimate the corona performance of any set of conductors. This paper first presents the design and construction of DC power supply, measurement system and data acquisition system to carry out the corona cage simulation and then shows the corona cage test results for three types of conductors. The DC corona cage was longitudinally divided into five equal lengths, and three inner sections were isolated from the outer cage ground to measure radio noise and corona current. The research measured the following: radio noise,corona current, television noise, audible noise, ion current density and meteorological conditions. The radio noise and corona current measuring circuits were installed between the outer and inner sections of the cage, and then calibration experiments and cage simulations were conducted. Since television noise has high frequencies 75 MHz, an antenna pick-up system has been selected to measure the television noise. The audible noise was measured by a conventional method, which measures the noise level with a microphone attached to the cage. The ion current density was measured by a plate electrode manufactured from a metal flat board. To obtain a satisfactory set of conductor design data, it is necessary to examine corona test results on a large number of conductor geometries. Therefore, a number of experiments were conducted on several bundle types. To reliably analyze corona discharge phenomenon, corona cage test data were obtained over a long period of time, under various weather conditions, and expressed as a statistical distribution. In conclusion, it is quite clear from test results that conductor geometries play an important role in establishing the magnitude of corona noise. Based on this result, we determined the environmentally friendly conductor bundle type for HVDC ±500 kV overhead transmission line.