Abstract: A power conversion device includes a major circuit part converting a power of a distributed power source into AC power corresponding to a power system, and a controller controlling an operation of the major circuit part; the controller includes an estimated value calculation part and a reactive power calculation part; the estimated value calculation part calculates an estimated value of a resistance component of a system impedance of the power system, an estimated value of a reactance component of the system impedance, and an estimated value of a voltage value of the infinite bus power system based on an active power value of a connection point to the power system, a reactive power value of the connection point, and a voltage value of the connection point.

Abstract: A process for producing ethylene-propylene block copolymer which comprises(1) The first step of reacting propylene or a mixture of propylene and ethylene in the presence of a catalyst composed essentially of(A) a solid catalyst component containing magnesium, titanium and a halogen as the indispensable ingredients,(B) an organoaluminum compound, and(C) a silicon compound (1) represented by the formula R.sup.1 R.sup.2 Si(OR.sup.3).sub.2, wherein R.sup.1 is an alicyclic hydrocarbon group of 5-20 carbon atoms and R.sup.2 and R.sup.

Abstract: The present invention relates to a process for producing ethylene propylene block copolymers excellent in appearance, elongation and impact resistance when molded by a gas phase polymerization which can be conducted in a stable manner.The process of the present invention comprises the first step of polymerizing propylene by using a catalyst system composed essentially of(A) a solid catalyst component containing magnesium, titanium, and a halogen as the indispensable ingredients,(B) an organoaluminum compound, and(C) a silicon compound represented by the formula R.sup.1 R.sup.2 Si(OR.sup.3).sub.2, wherein R.sup.1 is an alicyclic hydrocarbon group and R.sup.2 and R.sup.3 are each a hydrocarbon group, to form a propylene homopolymer, and the second step of then polymerizing ethylene and propylene with further addition of a silicon compound represented by the formula R.sup.4 R.sup.5.sub.a Si(OR.sup.6).sub.3-a, wherein R.sup.4 is an aromatic hydrocarbon group, R.sup.

Abstract: For use in gas phase polymerization apparatus having an agitator in a fluidized bed polymerization reactor, the present invention provides a gas distributor which has holes, and caps covering the respective holes from above and each having an opening oriented in a substantially horizontal direction at an angle of about 90 to about 135 deg with, and outwardly of, a tangent to a circle centered about the center of the reactor whereby an increase in the gas solid ratio can be prevented in the region above the distributor to ensure efficient discharge of the polymer produced, and the polymer particles can be prevented from falling into a gas room thereunder.