캐나다의 고압직류송전선과 손실보상

Recently, high voltage direct current (HVDC) transmission systems have been used in many countries such as Canada not only because HVDC converter for bulk transmission has been developed and the demand for direct current increases but also because HVDC has many advantages for long distance transmission compared to HVAC. In South Korea, HVDC transmission lines are going to be built in the sections from northern Dangjin to Koduk and from Sinhanwol to Singapyeong. 「An Act on Compensation and Support for the Surrounding Area of Power Transmission and Converting Structures」, which was adopted in 2014 by the National Assembly of Korea, provides the legal grounds such as support for the surrounding area of power transmission and converting structures, monetary compensation for condemned land and offer to buy a residential house, etc. However, the Act has a defect that 500kV HVDC is not regulated by it because it defines the surrounding area of power transmission line as the area near the right-of-way of 765kV and 345kV transmission lines respectively. HVDC system, which is used for bulk power transmission for long distance, boosts AC power generated at a power plant to a high voltage through AC transformer and converts to HVDC through a rectifier for transmission, then reconverted to AC through an inverter and transforms to a lower voltage for use. A few companies have exclusively developed this high technology, which has been widely used in the countries including Canada and China. In Canada, the Provinces have the Surface Right Board to regulate the legal disputes over installation of power transmission lines. In case of installing HVDC, an operator usually does not purchase the land outright for a right-of-way, but negotiates with a landowner for fair and reasonable compensation. When the negotiation fails, the operator may apply for a Right of Entry Order. If the order is issued, the operator compensates for entry fee and easement, etc. Determining the compensation, the Board may consider the factors such as the amount of the land granted to the operator based on the highest approved use, the loss of use value, nuisance, inconvenience and noise, etc. However, the operator does not compensate for electromagnetic fields because the static magnetic fields produced by HVDC is usually very low and may be ignored unlike that by HVAC. Due to an advantage that an HVDC transmission can carry a higher effective voltage than an HVAC of equivalent size, HVDC is more economical transmission method than HVAC when the transmission distance is greater than the break even distance, despite the cost of an HVDC converter station is much higher than that of an AC substation. It is also expected that HVDC is to be more used in the future in that it needs smaller size of steel tower and right-of-way than those of HVAC. In particular, the fact that HVDC generates electromagnetic fields very low compared to HVAC has an important implication for Korea where has had a lot of claims against power transmission lines.