Nissin Electric Co., Ltd.

Masakuni Asano

Noriaki Tokuda

Yoshio Matsubara

Shoji Nishimura

Yoshifumi Minowa

Tokuo Emura

Yoshihiro Hada

Jun Nishidai

A power fluctuation monitoring unit which monitors and detects the power fluctuation at a receiving point by means of the measurement results of the voltage at injection point of an intermediate-order harmonic current and the current at incoming line 10, a power compensation unit which forms the compensation power injection signal for canceling out the power fluctuation based on the detection results of the power fluctuation, and an inverter device which is driven and controlled by the signal resulting from the addition of the intermediate-order harmonic current injection signal and the compensation power injection signal and injects the intermediate-order harmonic current and the compensation power into the injection point, are equipped.

Isolated operation prevention device for distributed power supply and interharmonic detection method

In a current-limiting device, a plurality of current-limiting elements are connected in series to one another, and are inserted between the system power source of an electric power system and the load thereof. In the device, transformers, the number of which is equal to that of the current-limiting element S through Sn, are arranged. The primary windings of the transformers are connected to the current-limiting elements in the same polarity, respectively, and all the secondary wings thereof are connected in parallel to one another.

Current-limiting device

A system interconnection device connected between two systems, such as a commercial bus line carrying power from a commercial power line and a private bus line carrying power from a private power generator, is able to connect and disconnect the two systems, and, in the event of a fault, has a current-limiting effect, thus preventing instantaneous voltage drop of the respective bus lines. In the system interconnection device, unit parallel circuits made up of diodes and DC reactors are serially connected so that the diodes thereof have opposite directions. With this structure, in realizing operations equivalent to those of a conventional system interconnection device having a DC reactor between DC terminals of a single-phase rectifying bridge circuit, the number of diodes, which are rectifying elements, can be halved. This not only enables reduction of the total cost of elements, but also, particularly in high-voltage and extra-high-voltage systems, enables great reduction of the cost and space devoted to insulation.

System interconnection device and method of designing same

Growing community of inventors

Kyoto, Japan

Masakuni Asano