JPH0544625A - Variable speed pumped storage generator - Google Patents

Abstract

(57) [Summary] [Purpose] To reduce the output voltage required at the pumping start of the power converter. [Structure] At the start of pumping, a short-circuiting switch 4 is turned on to short-circuit the primary side 1a of the synchronous machine 1 via a resistor 7. After that, the variable frequency power is supplied from the power converter 5 to the secondary side of the synchronous machine 1.
Supply to 1b to start the synchronous machine 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable speed pumped storage power generation system, and more particularly to a pumping start system for the system.

[0002]

2. Description of the Related Art In a variable speed pumped-storage power generator using an AC excitation type synchronous machine, as a method of starting pumping, that is, starting as a pump, a method of short-circuiting the primary side and operating the synchronous machine as a wound induction motor is known. is there. FIG. 3 is a circuit diagram showing the configuration of a conventional variable speed pumped storage hydropower system adopting this type of system. In the figure, 1 is an AC excitation type synchronous machine (hereinafter abbreviated as synchronous machine) connected to an AC system 3 via a main switch 2, and 4 is a short circuit for short-circuiting a primary side 1a of the synchronous machine 1. The switches 5 are power converters whose input side is connected to the AC system 3 via the transformer 6 and whose output side is connected to the secondary side 1b of the synchronous machine 1, respectively. Supply to the secondary side 1b.

Next, the operation, especially the procedure for starting the pumping will be described. First, the main switch 2 is opened and the short-circuit switch 4 is turned on to bring the primary side 1a of the synchronous machine 1 into a short circuit state. After that, the low-frequency power is supplied from the power converter 5 to the synchronous machine 1
Supply to the secondary side 1b. As a result, the synchronous machine 1 operates as an induction motor and starts rotating. The output frequency of the power conversion device 5 is increased in accordance with the increase in the rotation speed of the synchronous machine 1, and finally is increased to the output frequency that is the rated synchronous frequency plus the so-called slip frequency of the induction motor.
From this state, the short-circuiting switch 4 is opened and the main switch 2 is closed to start pumping operation at the synchronous frequency.

[0004]

Since the conventional variable speed pumped storage hydropower system is constructed as described above, the power converter 5 requires a particularly high output voltage at the start of pumping. If this is explained according to an actual example, for example, the primary side voltage of the synchronous machine 1 during power generation and rated operation of pumped water is 1
For equipment with 6.5kV and secondary voltage of 2.0kV, it is necessary to supply a voltage of approximately 4.5kV to the secondary side of synchronous machine 1 at the start of pumping. Therefore, due to the existence of this pumping start condition, there is a problem in that the capacity of the power conversion device 5 must be significantly increased beyond the value determined in its original power generation and pumping operation. The present invention has been made to solve the above problems, and can reduce the output voltage required at the time of pumping start of the power conversion device so that its capacity can be reduced to the value required for the original power generation and pumping operation. The object is to obtain a variable speed pumped storage power generation device that can be stopped.

[0005]

In the variable speed pumped-storage power generation apparatus according to the invention of claim 1, the primary side of the AC excitation type synchronous machine is short-circuited via a resistor at the time of starting pumping.

According to the second aspect of the present invention, a boosting transformer is inserted between the secondary side of the AC excitation synchronous machine and the power conversion device at the time of pumping start.

[0007]

In the first aspect of the invention, the resistance increases the starting torque, and the supply voltage to the secondary side can be reduced accordingly.

According to the second aspect of the present invention, the output voltage of the power converter rises by passing through the step-up transformer and becomes a voltage necessary for starting and is supplied to the secondary side.

[0009]

【Example】

Example 1. 1 is a circuit diagram showing a configuration of a variable speed pumped storage hydropower system according to Embodiment 1 of the present invention. The only difference from the prior art is that a resistor 7 is inserted in series with the short-circuit switch 4. In this embodiment, when the short-circuiting switch 4 is turned on at the pumping start, the primary side 1a of the synchronous machine 1 is short-circuited via the resistance of the resistor 7. As a result, the starting torque generated in the synchronous machine 1 is increased by the so-called proportional change due to this resistance even if the supply voltage to the secondary side 1b of the synchronous machine 1 is the same, and the acceleration characteristic of the synchronous machine 1 is improved accordingly. To do. In other words, the value of the output voltage required for the power conversion device 5 can be reduced at the start of pumping. Therefore, the required capacity of the power conversion device 5 can be reduced, and if the resistance value of the resistor 7 is set appropriately, the capacity of the power conversion device 5 can be kept at its original value required for power generation and pumping operation. Therefore, the power converter 5 can be downsized and the price can be reduced.

Although the resistor 7 is inserted in the above embodiment, a reactor may be inserted to utilize the resistance.

Embodiment 2. Second Embodiment FIG. 2 is a circuit diagram showing a configuration of a variable speed pumped storage hydropower system according to a second embodiment of the present invention. What is different from the conventional one is the circuit configuration between the synchronous machine 1 and the power conversion device 5, which will be described below. That is, 8 is a step-up transformer, 9 is a switch that is turned on when starting pumping, and 10 is a switch that is turned on when pumping power.

Next, the operation will be described. At the start of pumping, the main switch 2 is opened, the short-circuit switch 4 is closed, the switch 9 is closed, and the switch 10 is opened. After that, the power conversion device 5 outputs electric power of a low frequency, and the voltage thereof is boosted by the boosting transformer 8 to become a high voltage and supplied to the secondary side 1b of the synchronous machine 1. The torque increases as the supply voltage increases, and the synchronous machine 1 rapidly increases its rotation speed. The point that the output frequency of the power conversion device 5 is increased in accordance with the increase in the rotation speed of the synchronous machine 1 is the same as in the conventional case. When the rated frequency is reached, switch 9 is opened and switch 10
To close and start the original pumping operation.

In this case, since the step-up transformer 8 is inserted, the output voltage of the power converter 5 can be reduced with respect to the voltage value to be supplied to the secondary side 1b of the synchronous machine 1. Accordingly, the capacity of the power conversion device 5 can be reduced. If the step-up ratio of the step-up transformer 8 is appropriately set, the capacity of the power conversion device 5 can be kept at its original value required for power generation and pumping operation, and the power conversion device 5 can be made compact and inexpensive. To do.

[0014]

Since the present invention is configured as described above, it is possible to reduce the output voltage required at the time of pumping start of the power conversion device, and to realize the downsizing and cost reduction of the device.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a configuration of a variable speed pumped storage hydropower system according to Embodiment 1 of the present invention.

FIG. 2 is a circuit diagram showing a configuration of a variable speed pumped storage hydropower system according to Embodiment 2 of the present invention.

FIG. 3 is a circuit diagram showing a configuration of a conventional variable speed pumped storage power generation device.

[Explanation of symbols]

 1 AC excitation type synchronous machines 1a, 1b Primary side and secondary side of synchronous machine 1 3 AC system 4 Short circuit switch 5 Power converter 7 Resistor 8 Step-up transformer

Claims (2)

[Claims] 1. An alternating current excitation type synchronous machine having a primary side connected to an alternating current system and a power conversion device connected to the alternating current system for supplying electric power of a variable frequency to a secondary side of the alternating current excitation type synchronous machine. A variable-speed pumped-storage power generation apparatus, wherein when starting pumping, the primary side of the AC excitation synchronous machine is disconnected from the AC system and short-circuited to start as an induction motor by the power from the power conversion apparatus. A variable speed pumped storage power generation device characterized in that the output voltage required at the time of starting the power conversion device is reduced by short-circuiting the primary side of the AC excitation type synchronous machine via a resistor at the time of starting. 2. An alternating current excitation type synchronous machine having a primary side connected to an alternating current system, and a power conversion device connected to the alternating current system for supplying variable frequency electric power to the secondary side of the alternating current excitation type synchronous machine. A variable-speed pumped-storage power generation apparatus, wherein when starting pumping, the primary side of the AC excitation synchronous machine is disconnected from the AC system and short-circuited to start as an induction motor by the power from the power conversion apparatus. At the time of starting, by inserting a step-up transformer between the secondary side of the AC excitation synchronous machine and the power converter, the output voltage required at the start of the power converter is reduced. Characteristic variable speed pumped storage generator.