Mitsubishi Denki Kabushiki Kaisha

Other

The Tokyo Electric Power Company, Incorporated

Isao Iyoda

Makoto Terada

Hiroshi Suzuki

Koji Temma

Hisao Taoka

Nobuyuki Sato

Isao Furo

Shigeru Warashina

Katsuhiko Matsuno

Hideo Noguchi

Yukio Kojima

Yoshinao Matsushita

Akifumi Iwamaru

Yoshiyuki Kobayashi

When a voltage of a system is stabilized by connecting the system with two types of voltage regulators, i.e., a slow-response tap-changing transformer and a quick-response reactive power regulator, it is not always clear how characteristics of the reactive power regulator should be regulated. Moreover, the regulation takes much time. In a range where voltage fluctuation of the system is small and a tap-changing transformer can cope with the change, gain of a reactive power regulator is set to be low, and its output is restrained. In a range where voltage fluctuation of the system is large and the voltage deviates from a width of a dead zone of the tap-changing transformer, gain of the reactive power regulator is set to be high, and regulating current is fully utilized.

Reactive power compensator

A load management and control apparatus comprising a control unit in which system voltage and a power flow state are measured to make an arithmetic decision by using the resultant variations in voltage and reactive power so as to estimate system reactance, and the estimated system reactance is used to carry out control operation while establishing unique relationship between tap changing operation of the transformer and connection or disconnection of the reactive power supply unit in the receiving side sub-station so as to set voltage and power factor of the receiving side of power system in desired ranges, whereby in a receiving end side substation, it is possible to prevent frequent tap changing operation of the transformer, and adjust system voltage not only to reduce the voltage deviation but also to provide integrated and reasonable management of the reactive power.

Load management and control apparatus

A semi-conductor bridge thyrister converter circuit for converting AC power into DC power with suppression of the higher harmonics generated by the circuit including a semi-conductor converter circuit, a control circuit, and instrument transformers for measuring the voltages and the currents at the source and the load side at a node. On the basis of the outputs of these transformers, the control circuit controls the control delay angle and the overlap angle of the thyristers of the semi-conductor converter circuit such that higher harmonics generated by the converter current are reduced to a minimum as seen from the power system side.

Thyristor converter system with higher harmonics suppression

An electric power system simulator comprising first calculator which calculates a generator dynamic characteristic, second calculator which calculates a load dynamic characteristic and third calculator which calculates power transmission condition of an electric power system network, then the first calculator cyclically obtains an amplitude and a phase of an internal induced voltage of the generator based on data on an output power and a terminal voltage of the generator, and the second calculator calculates a load equivalent admittance at predetermined time based on data on an A.C. voltage at a load installation point, and the third calculator calculates a current flowing in each element of the electric power system based on respective data obtained by the first calculator and the second calculator and an electric power system network impedance to obtain the output power and terminal voltage of the generator, so that a condition change of the electric power system including the generators is serially simulated by alternately executing the calculations of the first and the second calculators and the calculation of the third calculator.

Electric power system simulator

Growing community of inventors

Tokyo, Japan

Isao Iyoda