A Design For Electromagnetic Environment Monitoring System Of ±660kV DC Transmission Line

Since our own technology was used in Zhoushan HVDC project in 1987, the HVDC project has been developing rapidly in China. At present, China has become the country that has the largest HVDC capacity in the world. Taken into consideration economic and environment, a large number of analyzes and studies at home and abroad reveal that the most optimal transfer voltage of DC transmission should be±660kV when the power transmission in a distance of 1400～3000km. Therefore, the electromagnetic environment of HVDC transmission line should be analyzed and studied, and the electromagnetic parameters should be monitored.In this article, the main electromagnetic parameters included transmission line synthesis electric field near the ground, around the transmission line audible noise, radio interference, ground magnetic field and corona effects of Ningdong-Shandong ±660kV DC transmission line which have running for two years was analyzed and simulated. Through the analysis and simulation of electromagnetic parameters, we found that ground magnetic field generated by DC transmission line has the smallest influence on the environment, radio interference comes second, and the ground synthetic electric field and audible noise has the greatest influence. So, these parameters should be monitored. Aiming at ground magnetic field and audible noise generated by ±660kV DC transmission line, an monitoring system for electromagnetic environment of DC transmission line was designed. A monitoring terminal nearby power lines and a detecting system on a central computer were included in this system. Because the data volume sent and received by monitoring terminal is small, the GPRS network transmission which has most extensive coverage and mature technology was used in data transmission. Master controller, field monitor, noise monitor and GPRS module was included in monitoring terminal. The important function of monitoring software in central computer include real-time data viewing, analysis of historical data and set up the monitoring terminal.The electric field intensity and the audible noise detected by the system, and data was sent to monitoring central computer through the GPRS. Some related parameters were monitored by monitoring software, also the history data can be checked and analyzed.