Constraints on the use of local compensation for the correction of neutral voltage displacement caused by the influence of nearby power lines

The use of the same right of way for several power lines is a popular technical solution nowadays. The drawback of this solution is the growth of interferences between nearby power circuits of transmission lines, especially in the case of multi-circuit lines positioned on the same pylons. Neutral voltage displacement in the network with resonant earthing caused by the influence of nearby power line is one of known effects of the interaction. The efficiency of the use of local compensation of neutral voltage displacement in the 110 kV resonant earthed network containing the 21 km segment of combined 380/110 kV overhead line is studied in the offered paper. It is shown that the voltage displacement influenced by the combined overhead line can be propagated over full 110 kV network containing several thousand km of overhead transmission lines. Taking into account the earth fault protection requirements it is shown that local compensation devices are not always capable to reduce the neutral voltage displacement down to the permissible level. Possible practical measures for the reduction of the influenced neutral voltage displacement are discussed in the paper.