Simulation of load displacement in parallel lines using series connected tapped reactor

Different parallel transmission lines can be utilized when there is a power flow from a surplus generation area to a load centre in a meshed power grid. The current distribution in these lines depends on the inverse value of the line impedances. The current path with the lowest impedance will reach its maximum transmission capacity considerably earlier than the other parallel paths. It thus determines the maximum transmittable power, although the other parallel paths are not loaded to full capacity. There are different possibilities to influence the current distribution, for example using a phase shifting transformer (PST) or reducing the impedances of the partially loaded lines with series capacitors. Another possibility is a tapped reactor series connected to the overloaded line. The different taps are switched with circuit breakers. The current will be displaced into the other paths by increasing the reactors impedance. This paper presents a simulation model of power transmission with three parallel transmission lines, using PSCAD Software. A tapped reactor is inserted into the line with the least impedance. The simulation is carried out with different steady state load flows, and the respective effect on current distribution caused by varied reactor impedance is investigated. Furthermore, the stress on the components, for example the reactor and the circuit breakers, while changing the reactors impedance, is analyzed.