JPH0687680B2 - Pumped storage generator system - Google Patents

Description

TECHNICAL FIELD The present invention relates to a pumped-storage power generator system in which an automatic frequency control (hereinafter, referred to as AFC) adjustment range during pumping operation is increased.

[Conventional technology]

Generally, in recent power systems, the AFC adjustment capacity in the midnight zone is insufficient due to the increase in the ratio of nuclear power and the increase in the number of times of thermal power start / stop, etc., and the input adjustment of pumped storage power plants is indispensable to cope with this. It was In response to this, variable speed pumps have been closed up.

Here, FIG. 3 shows a simple principle diagram of the variable speed pumping machine. In the figure, 1 is an armature of an induction generator motor, 2 is also a rotor (secondary coil), 3 is a reversible pump turbine, 4 is a shaft, 5 is a cycloconverter transformer, 6 is a cycloconverter, and 7 is a rotation. A number detector, 8 is a rotation speed controller. Here, in order to operate the reversible pump turbine 3 at a variable speed, the method of secondarily exciting the wound-rotor induction motor as described above is usually adopted. Therefore, even if the rotation speed changes, parallel operation with the system becomes possible by adjusting the frequency of the secondary excitation so as to match the system frequency. As the frequency conversion device, a cycloconverter method for making alternating current from alternating current to direct current is usually used.

An example of a conventional starting circuit is shown in FIG.

1 is a stator (armature) of an induction type variable speed generator-motor, 2 is a rotor of the armature 1, 6 is a cycloconverter, 10 is a transformer, 11 is a generator breaker, 12 is a phase inversion disconnector, Reference numeral 13 is a main transformer, 14 is a starting disconnector, and 15 is a starting breaker.

Next, the operation will be described.

First, at the time of starting, 1 of the stator 1 of the induction type variable speed generator motor
The secondary side is short-circuited by the disconnecting switch 14 for starting, and the winding type induction motor 2
While the secondary winding rotor 2 is regarded as the secondary winding, the secondary side rotor 2 is regarded as the primary winding of the winding-type induction machine 6 and excitation from the cycloconverter 6 performs low frequency variable frequency starting.

Next, when the intermediate speed (about 50% of the rated rotation speed) is reached, the frequency becomes large and it becomes difficult to control the cycloconverter. Therefore, the starting disconnector 14 is shut off and the starting breaker 15 is turned on to turn off the starter from the primary side. Switching to low voltage acceleration, opening the starting breaker 15 again near the rated speed, synchronizing with the cycloconverter 6 and turning on the generator breaker 11 to supply the system voltage and complete the start.

[Problems to be solved by the invention]

Since the conventional pumped-storage power generator system is configured as described above, the transformer 10 for starting needs to have a third winding, and the starting breaker 15 for the intermediate speed primary side is required, and There was a problem that the operation procedure at the time was complicated.

The present invention has been made to solve the above-mentioned problems, and it is a conventional cycloconverter that employs a circulating current method as an excitation method, and continuously operates from a stopped state of a pumped-storage power generator system to a specified speed near a synchronous speed. The purpose of the present invention is to obtain a pumped-storage power generator system in which the control circuit and the operating procedure are simplified by increasing the speed.

[Means for solving problems]

The pumped-storage power generator system according to the present invention is a generator motor.
The secondary side is short-circuited by a starter disconnecting switch, connected to the secondary side of the generator motor, and continuously operated from a stopped state of the pumped-storage generator system to a specified speed near the synchronous speed by a cycloconverter that uses the circulating current method as the excitation method. After speeding up,
The cycloconverter is once stopped so that the generator motor has no voltage, the disconnector for starting is opened, and the generator motor is synchronously inserted at the specified speed in order to operate the cycloconverter again.

[Operation] The pumped-storage power generator system according to the present invention does not require the reversal control of the positive and negative currents by adopting the circulating current method as the excitation method, and thus does not require the zero detection circuit and the gate switching circuit. In addition, it is possible to control from a large slippage stop state and to continuously accelerate from the stop state of the pumped storage generator system to a specified speed near the synchronous speed, and at a specified speed near the synchronous speed. Since the slippage is small, the starting breaker on the primary side for intermediate speeds is unnecessary.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. In the figure, the same parts as those in FIG.
In the figure, the difference between FIG. 4 and FIG. 1 is that the starting transformer
1 is a two-winding type in FIG. 1 for simplification, the breaker 15 for starting shown in FIG. 4 is also omitted, and the cycloconverter 6 is a non-circulating current control system in FIG. Then, the circuit is changed to the circulating current control method.

Next, the operation will be described. First, FIG. 2B shows a circuit diagram of a conventional non-circulating current control system, and FIG. 2A shows a circuit diagram of the circulating current control system used in the present invention. As shown in the figure, the conventional non-circulating current control method requires reverse control of the positive and negative currents, so that a zero detection circuit and a gate switching circuit are required as shown in FIG. (Small area), the secondary circuit frequency is small, so it is possible to switch the current between positive and negative. However, when the speed is low and the slippage is large, the secondary circuit frequency becomes large and the current cannot be switched between positive and negative. At times, as shown in FIGS. 2 (b) and 4, the control circuit and operation become complicated. However, in the circulating current method, the reversal control of the positive and negative currents unlike the non-circulating current method is not necessary, and the control can be performed from the stopped state with large slippage. Therefore, as shown in FIG. Also, the gate switching circuit is not required, which simplifies the configuration and simplifies the starting method. Therefore, in FIG. 1, the armature 1 which is the primary side of the induction generator motor is short-circuited by the starting disconnector 14, and the cycloconverter 6 on the secondary side controls V / F (voltage / frequency = constant control).
Then, after the speed is increased at once from the stopped state to about 90% of the specified speed synchronous speed), the cycloconverter 6 is temporarily stopped, the armature 1 of the induction generator motor is made non-voltage, and the disconnecting switch for starting 14
Open up. Then, the cycloconverter 6 is operated again, the frequency is adjusted at the specified speed, and the generator breaker 11 enters in parallel in parallel.

〔The invention's effect〕

As described above, according to the present invention, since the circulating current method is adopted as the excitation method of the cycloconverter, the reversal control of the positive and negative current as in the non-circulating current method is not necessary, and the sliding state is prevented from a large stop state. Therefore, the zero detection circuit and the gate switching circuit in the related art are not required, and the configuration can be simplified. In addition, it is possible to continuously increase the speed from the stopped state of the pumped-storage power generator system to the specified speed near the synchronous speed, and since the slip is small at the specified speed near the synchronous speed, it is for starting the intermediate speed primary side. There is an effect that a pumped-storage power generator system having a simplified control circuit and operating procedure can be obtained without requiring a breaker and without providing a starting transformer with a tertiary winding.

[Brief description of drawings]

FIG. 1 is a starting circuit diagram of a variable speed pumped-storage power generator system according to an embodiment of the present invention, and FIG. 2 (a) is a circulating current control system using a cycloconverter according to the present invention.
A block diagram showing a comparison of conventional non-circulating current control systems, FIG. 3 is a principle diagram of a general variable speed pumped storage generator system, and FIG.
The figure is a starting circuit diagram of a conventional variable speed pumped storage generator system. In the figure, 1 is an armature, 2 is a rotor, 6 is a cycloconverter, 10 is a transformer, 11 is a generator breaker, 13 is a main transformer, and 14 is a starting disconnector.

Claims (1)

[Claims] 1. A pumped-storage generator system in which a generator motor is a wound-type induction generator motor, and a secondary rotor of the generator motor is excited by a cycloconverter to perform a variable speed operation. As a starting device, the circulating current system is used as a circulating current system, the cycloconverter is also used as a starting device when the generator motor of the pumped-storage generator system is started, and the primary side of the generator motor is short-circuited by a starter disconnecting switch. After the pumping generator system is continuously accelerated by the cycloconverter connected to the secondary side to the specified speed near the synchronous speed, the cycloconverter is temporarily stopped to turn off the generator motor and then disconnect the starting circuit. So that the generator motor can be synchronously inserted again at its specified speed to operate the cycloconverter again. Pumped hydro system, characterized in that the.