| The ultra high voltage (UHV) power network is the transmission network with great AC and DC power which consists of 1000 kV AC and±800 kV DC transmission systems. It has the outstanding advantages including great transmission capacity, long transmission distance and little energy losses. According to the development planning till 2015, national electric power framework will cover all areas with UHV network framework as core. Meanwhile the construction for wireless and wire communication systems has been developing rapidly. In the field of wireless communication, the applications of radio to communication, navigation and orientation industries are comprehensive, and the greatest civilian mobile and 3G radio communication systems over the world have been established. These radio communication systems have the requirements on surrounding interference sources and metal barriers. In the field of wire communication, the most advanced communication network with the greatest size worldwide has also been developed, and the number of customers for internet broad band access has achieved the largest over the world.The UHV transmission line consists of iron towers with the height greater than 100m and bundled conductors with the diameter more than 1m, which will form the oversize metal mesh-shaped framework in the country. In the meantime, due to high voltage and large current for UHV transmission line, the complex electromagnetic environment will be developed along the line including electric, magnetic fieds and radio interference. It could have potential interference on surrounding wire and wireless communication systems, and there are the stricter challenges for computer devices applied to UHV network. So it is very critical technical problem to maintain the information safety of communication systems.There are scientific research plans especially developed by State Grid Corporation of China in 2006, And the plan has been ranked as the key project in the national science and technology pillar program during the 11th five-year plan period with the number of 2006BAA02A09. Based on the background, the paper includes:(1) For no effective arithmetic on passive interference of high voltage transmission lines to radio communication over the world,3D simulation model for passive interference is established based on Moments’(MOM) and multilevel fast multipole algorithm (MLFMA), the effective calculation for UHV transmission line could be developed using minicomputer. By the verification for the accuracy of model, it provides basic computation methods to study on passive interference of UHV network to radio communication.(2) For no measurement data about radio interference of UHV transmission line worldwide, by analyzing the mechanism, computation and measurement results on UHV test lines, the actual radio interference level and propagation characteristics of UHV transmission lines are grasped for providing technical reference on active interference study of UHV network to radio communication system.(3) Based on theoretic study, the information security influences of UHV power network on typical radio communication system, including are emphasized, including short-wave direction-finding and receiving stations, medium-wave navigation system and civil mobile communication network, and the passive and active interference levels of UHV transmission line to above radio communication systems are calculated. Finally the reasonable protection distances between UHV transmission line and above radio communication equipments, as reference to protection design of UHV projects and radio communication equipments.(4) The influences on information security of wire communication and computer network are studied, the mechanism for the interference of UHV network to wire communication system are presented. The physical structure of wire telecommunication network and popular network access technology are analyzed deeply, and the interference object focused on from UHV network, namely audio frequency telephone, and the internet access way, ADSL, are both put forward. Further the technology level and immunity ability of telecommunication equipment and cables are comprehensively checked, the probability evaluation model answering for the technology level of telecommunication network is established. By calculation, the reasonable and economic interference limit of UHV network to wire communication system is provided, and the additional interference protection measures adoptable for wire communication line are introduced.(5) The special immunity requirements and protection design are studied for computers and network equipments applied for UHV substation. Firstly the electromagnetic disturbance level and characteristics of UHV substation are analyzed, and the electromagnetic compatibility requirements of computers and network equipments applied for UHV substation are put forward. Then based on the instance of the electromagnetic compatibility design for trusted computer, the electromagnetic compatibility reinforcing design of computer and network equipments and the principles for information electromagnetic leakage-proof are summarized. By testing, the effectiveness of these measures is verified to satisfy the special guarantee requirements for the information security of UHV substation. |
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