Abstract: An compact dry transformer (1A) comprising a magnetic material core (2) and a coil assembly (3) assembled onto the core. The core comprises heat dissipating covers (4) with cooling fins (5) snug fitted over the core. The coil assembly is mounted on the core over a heat dissipating shifted inner jacket (9) made of non-magnetic material in close contact with the inner jacket. At least one first heat pipe (11) provided with cooling fins is located between the core and inner jacket in close contact therewith. The coil assembly further comprises a heat dissipating shifted outer jacket (13) made of non-magnetic material snug fitted over the high voltage winding. At least one second heat pipe (15) protruding out of bushings provided with cooling fins is located against the outer jacket in close contact therewith.

Abstract: A dynamic harmonic filter for an AC power system comprising at least one voltage source and at least one load is provided. The harmonic filter comprises a current sensing or voltage injection transformer connected in series with the voltage source and the load. One end of the primary of the transformer is connected to the voltage source, and the other end is connected to the load. The harmonic filter further comprises a parallel resonant LC circuit tuned to the fundamental frequency of the power system. One end of the secondary (S2) of the current injection of the voltage sensing transformer is connected to one junction of the parallel resonant LC circuit and the other end of the secondary of the current injection or voltage sensing transformer is connected to the other junction of the parallel resonant LC circuit through the secondary (S1) of the current sensing or voltage injection transformer.

Abstract: Compact dry transformer (1A) consisting of a magnetic material core (2) provided with a first heat sink consisting of covers (10) having cooling fins (11) on the outer surface thereof. The transformer also consists of a coil assembly (3,4) provided with a second heat sink consisting of enclosures (12) having cooling fins (14) on the outer surface thereof. The second heat sink further consists of jackets (15) with heat pipes (17) containing a thermic fluid having low boiling point at vacuum such as water. The heat pipes consist of evaporator portions and condenser portions having cooling fins (21) on the outer surface thereof. Due to the heat sinks heat dissipation efficiency of the transformer is improved (FIG. 3).