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1. 发明专利

JPH0553668A REACTIVE POWER COMPENSATOR 失效
公开(公告)号：JPH0553668A
公开(公告)日：1993-03-05
申请号：JP20954891
申请日：1991-08-21
申请人： HITACHI LTD , TOKYO ELECTRIC POWER CO
发明人： KONISHI HIROO , KAWAZOE HIROSHIGE , TOKIWA YUKIO , NAKAJIMA TATSUTO
IPC分类号： G05F1/70 , H02J3/18 , H02M7/48
摘要： PURPOSE:To speedily and stably control the advance and delay of the reactive power according to a command by corresponding to the change of system voltage. CONSTITUTION:The compensator is provided with a self-oscillation inverter 5 supplying the reactive power to the power system, an reactive power control means 20 inputting the difference between a command value Q and a detection value Q of the reactive power and calculating an amplitude command (k) of an inverter output voltage according to the difference at its output so as to reduce the difference, and compensation means 25 to 27 including an inverter control means 21 controlling the switching element of the inverter based on this amplitude command (k) and compensating the amplitude command (k) according to the detected value VS of the system voltage. The precedence control of the amplitude command according to the change of the system voltage enables the high-speed response as well as the stable control of the reactive power control.

2. 发明专利

JPH044755A SELF-EXCITED CONVERTER USING NORMALLY ON THYRISTOR 失效
公开(公告)号：JPH044755A
公开(公告)日：1992-01-09
申请号：JP10454190
申请日：1990-04-20
申请人： HITACHI LTD , TOKYO ELECTRIC POWER CO
发明人： WAKASUGI KENJI , KAWAI TADAO , TOKIWA YUKIO , ICHIKAWA FUMITOSHI
IPC分类号： H02H7/12 , H02M7/12 , H02M7/155 , H02M7/162
摘要： PURPOSE:To surely prevent short-circuiting of a normally ON thyristor at the time of starting conversion to enable applying the normally ON thyristor to an AC/DC converter, especially to a high-voltage-converter by turning OFF only a series switch prior to operating a breaker through adding the switch to the arm of the normally ON thyristor. CONSTITUTION:At the time of starting conversion, all switches 7 are turned OFF and then a breaker 1 is closed. In this case, electric current does not flow through the arm of normally ON thyristors 2. In gate pulse amplifiers 3, power is established by the current flowing through diodes 4 to control all normally ON thyristors 2 to OFF, immediately after the breaker 1 is closed. Accordingly, AC voltage is applied to both ends of each normally ON thyristor 2 and a converter is placed in a starting state. Because the power supply of the gate pulse amplifiers 3 is a charging type, the switching operation of the switch 7 is unnecessary after the gate power supply has been once established so that a normal operation as AC/DC converter is made possible.

3. 发明专利

JPH04208074A AC/DC CONVERTER 失效
公开(公告)号：JPH04208074A
公开(公告)日：1992-07-29
申请号：JP33938990
申请日：1990-11-30
申请人： HITACHI LTD , TOKYO ELECTRIC POWER CO
发明人： TANAKA CHIKARA , TOKIWA YUKIO , MIYAZAKI SATOSHI
IPC分类号： H02M7/06 , G05F1/10 , H02M7/12 , H02M7/155
摘要： PURPOSE:To improve reliability and to enable downsizing by disposing a series circuit of a thyristor with an overvoltage self-protecting function and a resistor in parallel with a smoothing capacitor, and providing a circuit for opening a changeover switch by detecting firing of a VBO free thyristor. CONSTITUTION:If a DC side voltage of an AC/DC converter 3 becomes abnormally high, when a forward voltage between terminals of a VBO free thyristor 5 exceeds an overvoltage self-protecting level, it is fired by an overvoltage. A discharging current of a smoothing capacitor 2 flows from the capacitor 2 through the thyristor 5 and a resistor 6 by firing, the DC voltage of the converter 3 is lowered, and damage due to an overvoltage can be prevented. A current flowing by firing is detected by a current detector 8, and a detection signal is sent to a switch controller 7. The controller 7 opens a changeover switch 4 if the detected current value becomes a predetermined value or more.

4. 发明专利

JPH03277121A CONTROL AND PROTECTION SYSTEM FOR SELF-EXCITATION TYPE CONVERTER 失效
公开(公告)号：JPH03277121A
公开(公告)日：1991-12-09
申请号：JP7333190
申请日：1990-03-26
申请人： HITACHI LTD , TOKYO ELECTRIC POWER CO
发明人： SHIMAMURA HIDEHIKO , KAWAI TADAO , TOKIWA YUKIO , SUZUKI KENICHI
IPC分类号： H02H7/122 , H02H7/16 , H02J3/18
摘要： PURPOSE:To protect a self-excitation type converter safely and surely and to control an effective use of equipment by detecting a discharge current of a direct-current capacitor when a trouble occurs, controlling discharge of the direct-current capacitor rapidly and by using the control function effectively even during the trouble. CONSTITUTION:A control and protection device 600 controls a converter and a direct-current switch 51 according to each relay operation signal. When a direct current short circuit occurs on the direct current side, a discharge current of a capacitor 40 flows toward the point where the short circuit occurred from the capacitor 40 while a high-speed direct over-current relay 100 installed on a direct-current capacitor circuit starts operation when it exceeds a detection sensitivity, opening a direct-current switch 51 to cut off the faulty current. From the start of the direct-current switch to the settlement of the trouble, the reactive power of an alternating current can be under control by the energy of the direct-current capacitor 40.

5. 发明专利

JPH02164231A AC TO DC CONVERTER 失效
公开(公告)号：JPH02164231A
公开(公告)日：1990-06-25
申请号：JP31641088
申请日：1988-12-16
申请人： HITACHI LTD , TOKYO ELECTRIC POWER CO
发明人： TANAKA CHIKARA , TOKIWA YUKIO , MIYAZAKI SATOSHI
IPC分类号： H02H3/00 , H02J1/00 , H02J5/00 , H02M7/12 , H02M7/155
摘要： PURPOSE:To improve the reliability of an apparatus by arranging a DC switch between a voltage type self-excited converter and a smoothing capacitor or said smoothing capacitor between the voltage type self-excited converter and DC switch or by using the arrangements at the same time. CONSTITUTION:When a short-circuit or ground fault occurs on the DC side, a short-circuit detector 12 or an earth detector 10 detects the fault so that an OFF signal is given from a gate control circuit 13 to a DC switch and the DC switch 4 is brought to an OFF state to cut OFF an overcurrent flowing through an AC to DC converter 1. In this manner, the overcurrent ceases to flow through the AC to DC converter 1 over a long period of time and the breakdown of the AC to DC converter 1 by the over-current can be prevented beforehand. Also, it is possible to prevent the discharge of the smoothing capacitor 3 so that an apparatus can be restarted even at high speed without recharging the smoothing capacitor.

6. 发明专利

JPH04368429A CONTROLLER FOR INVERTER 失效
公开(公告)号：JPH04368429A
公开(公告)日：1992-12-21
申请号：JP14296591
申请日：1991-06-14
申请人： HITACHI LTD , TOKYO ELECTRIC POWER CO
发明人： KONISHI HIROO , TOKIWA YUKIO , NAKAJIMA TATSUTO
IPC分类号： G05F1/10 , G05F1/70 , H02J3/18 , H02J3/38 , H02J3/50 , H02M7/48 , H02M7/515 , H02M7/525
摘要： PURPOSE:To obtain a controller for inverters which can be operated synchronously to the voltage phase of an AC system. CONSTITUTION:This controller for inverters is constituted of a synchronizing signal generation circuit 46 which detects the voltage phase of an AC system for operating an inverter synchronously to an AC system and outputs a synchronous signal, pulse signal generation circuit 48 which generates a control signal for controlling the inverter in accordance with the output of the circuit 46, and a control circuit 47 of a reactive power compensating device, etc. Therefore, a controller for inverters which can be operated synchronously to the voltage phase of the AC system can be obtained.

7. 发明专利

JPH04367011A METHOD AND DEVICE FOR POWER CONVERSION 失效
公开(公告)号：JPH04367011A
公开(公告)日：1992-12-18
申请号：JP14296791
申请日：1991-06-14
申请人： HITACHI LTD , TOKYO ELECTRIC POWER CO
发明人： KONISHI HIROO , KAWAZOE HIRONARI , KAWAKAMI JUNZO , NAKAMURA TOMOHARU , TOKIWA YUKIO , NAKAJIMA TATSUHITO
IPC分类号： G05F1/70 , H02J3/18 , H02M7/48
摘要： PURPOSE:To attain the method and a device for power conversion which can work stably and at a high speed as instructed without detecting the voltage phase of a system. CONSTITUTION:A power converter is provided with a means 430 which inputs the current and the voltage of the AC side of an inverter and obtains the instantaneous real power and the instantaneous imaginary power, and the means 414 and 418 which calculate both instantaneous real and imaginary power based on the level of the AC side voltage to obtain the real and imaginary currents and then calculate the signals showing the amplitude and the phase of the inverter based on the obtained real and imaginary currents. Thus it is possible to attain the method and the device which can work stably and at a high speed as instructed in a simple constitution without detecting the voltage phase of a system.

8. 发明专利

JPH02164230A DC POWER TRANSMISSION SYSTEM 失效
公开(公告)号：JPH02164230A
公开(公告)日：1990-06-25
申请号：JP31640988
申请日：1988-12-16
申请人： TOKYO ELECTRIC POWER CO , HITACHI LTD
发明人： TOKIWA YUKIO , MIYAZAKI SATOSHI , YOSHIZUMI TATSUNORI , KAWAI TADAO
IPC分类号： H02J1/00 , H02M7/12 , H02M7/17 , H02P9/00
摘要： PURPOSE:To obtain the interconnected transmission system of a pumped storage power station making a large remodeling unnecessary and solving the problem of stability by providing a self-excited converter instead of a separately excited converter and by controlling the output frequency of the self-excited converter. CONSTITUTION:At the time of starting an apparatus, a converter 5 is operated, a DC transmission line 4 is charged with electricity, and the DC side voltage of a self-excited converter 3 is set to a rated value. Then, the self-excited converter 3 is started at a low frequency and with a low voltage output. The synchronous generator of a pumped storage power station starts rotation by the output voltage. The frequency and output voltage of the self-excited generator 3 is gradually made higher so that the number of revolutions of the generator is raised, and pumping is started with suitable timing. Thereafter, a pump discharge rate of flow can be arbitrarily controlled according to the set value Pref of a conversion power. Thus, it is possible to eliminate large remodeling of a generator-motor and to operate a stable pumped-storage power station.

9. 发明专利

JPH02164229A DC POWER TRANSMISSION SYSTEM 失效
公开(公告)号：JPH02164229A
公开(公告)日：1990-06-25
申请号：JP31640888
申请日：1988-12-16
申请人： TOKYO ELECTRIC POWER CO , HITACHI LTD
发明人： TOKIWA YUKIO , MIYAZAKI SATOSHI , KAWAI TADAO
IPC分类号： H02J1/00
摘要： PURPOSE:To obtain a DC transmission system capable of operating multiple terminals stably by closing divided capacitors in the manner of causing no large disturbance, at the time of dividing a DC capacitor, providing respective capacitors with a switch and providing a parallel connection of the capacitors in the DC system in operation. CONSTITUTION:When a conversion office C is connected with the DC transmission system between conversion offices A, B in operation, a switch 4 is closed first to charge the conversion office C with electricity and thereafter switches 7-9 are closed successively. In a DC capacitor 6 at that time, because a rush current by closing takes a sufficiently small value so as not to influence the operation of the conversion offices A, B, the established operation system is not disturbed even if capacitors are successively charged with electricity by closing of said switches 7-9. Thus, it is easily realizable to provide the parallel connection of multiple terminals in a self-excited converter with a high capacity DC capacitor and to operate the terminals by the converter.

10. 发明专利

JP2728575B2 失效
公开(公告)号：JP2728575B2
公开(公告)日：1998-03-18
申请号：JP14296791
申请日：1991-06-14
申请人： HITACHI LTD , TOKYO ELECTRIC POWER CO
发明人： KONISHI HIROO , KAWAZOE HIRONARI , KAWAKAMI JUNZO , NAKAMURA TOMOHARU , TOKIWA YUKIO , NAKAJIMA TATSUHITO
IPC分类号： G05F1/70 , H02J3/18 , H02M7/48

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