摘要:
In a pumping-up generator/motor system comprising an induction generator/motor, at least one cyclo-converter connected to the secondary winding of the induction generator motor for controlling the rotational speed of the generator/motor in the motor mode and for maintaining the output frequency thereof in the generator mode at a constant level, the center of the speed range of the generator/motor in the generator mode is set near the synchronous speed thereof and a plurality of converter units constituting each cyclo-converter are connected in parallel in the generator mode, and in series in the motor mode thereby allowing the capacity of the cyclo-converter to be made smaller.
摘要:
An induction generator/motor system has an induction machine connected at its secondary side to a cyclo-converter. An induced voltage develops when the cyclo-converter pauses during a transient phenomenon occurring in the system. When the induced voltage exceeds a predetermined voltage range which covers the maximum output voltage derivable from the cyclo-converter, the polarity of thyristor converters of the cyclo-converter is switched such that the induced voltage is applied to a thyristor converter to be rendered conductive next in forward relationship therewith, thereby preventing occurrence of an overvoltage.
摘要:
A control system for variable speed hydraulic turbine generator apparatus comprises an induction generator connected at its primary side to an AC power line system, a secondary excitation controller connected to the secondary side of the induction generator and being responsive to a generator output command signal supplied externally to supply to the induction generator an excitation current which causes the induction generator to generate AC power at the same frequency as that on the AC power line system, a hydraulic turbine for rotating the induction generator, a guide valve for regulating the amount of water supplied to the hydraulic turbine, a rotation speed detector for detecting a rotation speed of the induction generator, a rotation speed command calculator for receiving a hydraulic turbine running condition signal inclusive of the external generator output command signal and calculating an optimum rotation speed command, a rotation speed controller for comparing the optimum rotation speed command with a rotation speed signal from the rotation speed detector and producing a guide valve opening control signal in accordance with a difference between the optimum rotation speed command and the rotation speed signal, and a guide valve driver responsive to the guide valve opening control signal to deliver to the guide valve a signal which controls the opening of the guide valve in accordance with the guide valve opening control signal.
摘要:
There is disclosed a protecting apparatus for a secondary excitation type variable speed AC generator/motor having a primary winding connected to an electric power system and a secondary winding each phase of which is AC excited by an independent power converter unit. The protecting apparatus is arranged to detect an electrical event which includes at least one of an overvoltage and overcurrent appearing at each phase of the secondary winding of the AC generator/motor, to decide whether the detected electrical event meets a predetermined condition and to close, when the electrical event detected in respect to any of phases of the secondary winding is decided as meeting the predetermined condition, a switch circuit connected in the corresponding phase of the secondary winding.
摘要:
A control system for a variable speed water turbine generator apparatus includes a first function generator that is responsive to an output command signal. The first function generator produces a rotation number command signal. A speed adjuster produces an output signal in accordance with a different signal between the first function generator output and an actual rotation number. An adder adds the generator output command signal to the speed adjuster output signal to determine an overall output command signal. An output aduster produces an output signal in accordance with a difference between the adder output and an actual power output of the generator for controlling the firing angles of the frequency converter. A second function generator, responsive to the generator output command signal, determines an opening command signal for the variable opening vanes. An opening adjuster produces an output signal in accordance with a difference signal between the second function generator output and an actual opening of the variable opening vanes to control the variable opening vanes. The first and second function generators increase command values for the rotation number and the variable opening vanes, respectively, as the output command signal increases. The frequency converter is further controlled to maintain the rotation number within a predetermined operation range.
摘要:
Disclosed is a control apparatus for a variable-speed hydraulic power generating system comprising a variable-speed a.c. electric generator connected to an a.c. electric power system and a hydraulic machine system including a water turbine for driving the generator and a guide vane for controlling an amount of water supplied to the water turbine. The control apparatus comprises a frequency converter connected between the electric power system and the generator for controlling electric power supplied from the generator to the electric power system, control means operating in response to at least an externally applied power generation command signal for controlling, on one hand, the frequency converter thereby controlling the electric power supplied from the generator to the electric power system and generating, on the other hand, a guide-vane opening command signal for controlling the guide vane thereby controlling the amount of water supplied to the water turbine, and means for reducing resonance which may occur in the hydraulic machine system when the rotation speed of the water turbine changes in response to a change of the externally applied power generation output command signal.
摘要:
A variable-speed power generating system comprises a variable-speed generator electrically connected at its primary winding to an electric power system and its secondary winding to the electric power system through a frequency converter and mechanically coupled to a driver driving the secondary side thereof, a phase detector generating an output signal representing a slip frequency in response to the application of a first input having a frequency component of an output generated from the primary winding of the variable-speed generator and a second input having a frequency component corresponding to the rotation speed of the driver, a controller controlling the frequency converter on the basis of a reference phase provided by the output signal of the phase detector, and regulating means for controlling the frequency converter so that, when the variable-speed generator is disconnected from the electric power system, the frequency applied to the secondary winding of the variable-speed generator may not deviate from a predetermined allowable range of variable frequency operation of the frequency converter.
摘要:
A semiconductor power conversion system comprising a multiphase bridge circuit which includes semiconductor devices having a controllable firing function and a reverse blocking characteristic, a gate control circuit which gives firing commands to the semiconductor devices, a short circuiting switch in which switching devices having a controllable firing function and a reverse blocking characteristic are connected in parallel with a DC output side of the multiphase bridge circuit, and a protection control device for performing a control for protecting the multiphase bridge circuit. The protection control device includes a device for detecting a commutation failure of the multiphase bridge circuit, and a device in response to the detection of the commutation failure for producing a blocking command for blocking the firing of the semiconductor devices of the multiphase bridge circuit and producing a short-circuiting command for firing the switching device which is short-circuited which bypasses current of the commutation failure. The protection control device further includes a device for detecting ending of a short-circuit based on the ceasing of current conduction of the short circuiting switch and for halting the blocking of the firing of the semiconductor devices of the multiphase bridge circuit.
摘要:
An improved electric power conversion system comprising a multi-phase bridge circuit composed of semiconductors such as thyristors and an associated firing circuit. It is so constructed that: if the AC input current Iac flowing in the bridge circuit is equal to or larger in value that the DC output current Idc flowing out of the bridge circuit, it will be decided than an inner defect or fault is caused, and possible expansion of inner defect will be prevented by disabling the firing circuit to extinguish the thyristors in the bridge circuit, and if the AC input current Iac is smaller than the DC output current Idc in value, the bridge is permitted to continue the operation of power conversion, thus eliminating unnecessary interruption which otherwise would be caused by exterior disturbances. Also, an improved electric power conversion system may be equipped with a device to prevent an adverse effect from being caused by abnormal rise of thyristors' temperature.
摘要:
A generator-motor apparatus with economical protection measures for use in a variable speed pumping-up electric power plant, having a main transformer, a secondary winding of which is coupled to an electric power system, a power system breaker connected to a primary winding of the main transformer, a syncronizing breaker connected in series with the power system breaker, a generator-motor, a rotor of which is mechanically coupled to the pump-turbine and an armature winding of which is connected to the power system through the synchronizing breaker, the power system breaker and the main transformer, and an excitation circuit, including a frequency converter for supplying a field winding of the generator-motor with AC voltage of the variable frequency and a converter transformer for feeding the converter, which is branched from a junction of the power system breaker and the synchronizing breaker.