JP2851490B2 - Pumped storage generator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pumped-storage power generator in which, for example, an AC excitation synchronous machine is connected to a pump turbine.

[0002]

2. Description of the Related Art Conventional pumped-storage power generators of this type include:
The following are known.

(1) FIG. 4 shows, for example, Japanese Patent Application Laid-Open No. 62-7708.
FIG. 2 is a block diagram for explaining the principle of the variable speed pumped-storage power generator disclosed in Japanese Patent Publication No. 2 (hereinafter referred to as “No. 2”). In FIG. Excitation Synchronous Machine M Operated with Electric Power
(Hereinafter abbreviated as AESM), 1 is an armature of the wound type induction motor, 2 is a rotor (secondary coil) of the induction motor, 3 is a reversible pump turbine, 4 is a shaft, 5 is a cyclone. A transformer for converter, 6 is a cycloconverter (hereinafter abbreviated as EX) as a converter for excitation, 7 is a rotation speed detector, and 8 is a controller of the cycloconverter.

FIG. 5 shows the pumping direction operation characteristics of the above-mentioned variable speed pumping power generator. The vertical axis indicates the pump input in%, and the horizontal axis indicates the pump head. 100% of the head is the highest head and the lowest head is 90%. Points P1 to P
4, P13, P14 indicate specific points, line L12 is the maximum pump input, L5 is the 100% pump input, L6 is the limit line of stable pump operation, L7 is the minimum pump input value at the minimum head. , The lines L8 to L11 have the rotational speeds of 102, 100, 97.
It is an operation characteristic curve when changing to 5,95%.

[0005] Always a rated speed (n = 10
Pumping direction driving characteristics pumped storage device which is operated at 0%) based on the thus uniquely pump input is determined by the lift in the characteristics shown in line L9 in FIG. 5, the case of the variable-speed pumped-storage power generator The pump input can be adjusted within the range connecting the points P2 to P4 by lowering the rotation below the rated rotation speed, and the range connecting the points P13, P14, P2 and P3 by increasing the rotation above the rated rotation speed. Adjustment of pump input is possible within P13, P2, P4
The area surrounded by P14 is operable.

(2) FIG. 6 shows a cycloconverter type variable speed pumping system shown in, for example, "Exciting System Protection Method for Variable Speed Pumping Power Generation System", 11th-55th and 11th-56th, IEEJ National Convention 1991. FIG. 5 is a block diagram of a power generator, in which the same parts as those in FIG. 4 are denoted by the same reference numerals, and redundant description will be omitted. In FIG. 6 , reference numeral 9 denotes a cycloconverter as a frequency conversion device, and an overvoltage suppression thyristor 10, an overvoltage suppression arrester 11, and an overvoltage detection circuit 12 are connected in parallel to its input side.

Next, the operation will be described. In order to operate the AESM at a variable speed, a method of secondary excitation of the AESM is usually adopted. Even if the rotational speed changes, parallel operation with the system is possible if the frequency is corrected by secondary excitation by the amount of slip so as to match the system frequency.

It is known that when a system fault occurs, an overvoltage occurs secondarily to the AESM. The overvoltage detection circuit 12 detects the overvoltage, and the overvoltage suppression arrester 11 is fired to suppress the overvoltage. Was.

(3) FIG. 7 shows, for example, JP-A-3-11739.
Is a block diagram showing an outline of a cycloconverter form variable-speed pumped-storage power apparatus shown in 6 discloses, in FIG. 4, the same parts for a repeated explanation thereof are denoted by the same reference numerals. In FIG. 7 , 13 is a current transformer for an instrument, and 14 is a transformer for an instrument. FIG. 8 is a circuit diagram of a 12-phase non-circulating current type cycloconverter applied to the above device.

Next, the operation will be described. First, AES
To operate the M synchronously at a variable speed, the armature 1 of the AESM is used.
An AC excitation method for secondary excitation of the magnetic field is usually adopted. This excitation method is, for example, as shown in FIG.
The secondary voltage obtained by converting the output voltage of the above by the converter transformer 5 is input to EX6.

In general, in order to operate the synchronous generators in parallel, if the three elements of frequency, voltage magnitude, and phase of both machines do not match, disturbance occurs at the same time as the parallel operation, so that the rotor 2 is always used. It is necessary to correct the frequency by the secondary excitation by the amount of the slip so that the frequency coincides with the system frequency even when the rotational speed of the motor increases.

Therefore, as a frequency conversion function of EX6,
A cycloconverter control method is used in which AC power having different frequencies is directly obtained from an AC power supply by using the switching action of a thyristor and supplied to the rotor 2 of the AESM.

The EX 6 includes a position signal of a rotational position detector (for example, a resolver) 7 of the rotor 2 of the AESM, a generator output current by the current transformer 13, and an instrument transformer 14.
The AESM is controlled by a cycloconverter controller 8 which receives the generator output voltage and the like as a control element, and controls the AESM so that the finally set power and optimum rotational speed are obtained.

(4) FIG. 9 shows, for example, IEEJ, 107, 3
No., No. 62, pp. 210, FIG. 12 is a block diagram of a pumped-storage generator shown in FIG. 12, where M is an AESM having an armature 1 and a rotor 2, 3 is a pump-turbine directly connected to the AESM, 15 Is a cycloconverter, 16 is an automatic current control circuit, 17 is a load adjustment circuit, 18 is an output setter, 19
Is the input / output control servo of the pump turbine 3, 20 is the governor, 2
1 is a rotation speed calculation circuit, 22 is a valve opening calculation circuit,
N, H, and GVO are actual generated power, rotation speed, head,
This is the guide vane opening. Zero of each suffix indicates a command value.

[0015] In the above configuration, so that the set power as shown in FIG. 10 (65P), the output setter 1
8, the load setting circuit 17 and the automatic current control circuit 16 control the cycloconverter 15 to control the power as P, and to set the output setting unit 1 to the optimum rotation speed (N ₀ ).
8, the input / output control servo 19 is controlled by the rotation speed calculation circuit 21, the governor 20, and the valve opening degree calculation circuit 22, and the rotation speed N
Drive the AESM.

[0016] (5) Figure 11 is a block diagram showing a starting device for a variable speed pumped storage power generation apparatus shown in Figure 9, the duplicated description thereof is omitted with like reference numerals denote the same parts as FIG. Figure 1
In 1 , 23 is the circuit breaker for AESM, 24 is AES
M phase switching disconnector, 25 a main transformer, 26 an EX circuit breaker, 27 a starting circuit breaker, 28 a starting transformer, 2
9 is a circuit breaker for a starting transformer, and 30 is a thyristor starting device.

Next, the operation of the starting device will be described. The pumping direction disconnector (P side) of the phase switching disconnector 24 is turned on, the breakers 26 and 29 are turned on, the water surface of the pump turbine 3 is first pushed down by a start command, and then the breaker 27 is turned on. The thyristor starting device 30 starts the starting. The speed is increased by the thyristor starting device 30, and the excitation during the speed increase is EX6.
DC or low frequency (slip 3% or less) excitation by
When the vehicle is accelerated to near the synchronous speed, the starting circuit breaker 27 is released, the EX 6 is controlled to perform uniform speed control, and the generator circuit breaker 23 synchronously turns on. After exhausting the air for pushing down the water surface, the priming pressure is established, the guide vanes are opened, and the pumping operation starts. Incidentally, as a conventional example relating to the starting device pumped storage devices and 11 of Figure 9, Sho 60-20107
8, Japanese Patent Application Laid-Open No. 2-111300,
No. 51910 and the like.

[0018]

Since the conventional pumped-storage power generator is configured as described above, it has the following problems.

First, in the pumped storage power generator of the above (1), the output of EX6 is very low frequency and close to DC at very low frequency (S = 0), that is, near the rated speed (n = 100%). By energizing one arm of the three phases for a long time, the capacity of EX6 must be thermally increased, which is uneconomical.

In the cycloconverter type variable speed pumped storage power generator of the above (2), once the overvoltage protection circuit is operated,
If the return becomes difficult, the return circuit becomes complicated,
It is necessary to provide an overvoltage protection device on the output side of X6, and since the configuration is complicated, the device space is large and uneconomical.

The EX 6 always detects the number of revolutions of the rotor 2 and outputs A at a slip frequency due to a difference between the system frequency and the phase.
Since the ESM is excited, A
As soon as the generated voltage of the ESM and the system voltage matched, they were connected. This does not confirm that the frequency and phase always match, but the voltage and phase are set to 3 as in the case of the conventional synchronous machine.
Since the phase circuits are compared and the synchronization is determined, there have been problems such as parallel connection under insufficient conditions and a complicated device.

In the cycloconverter type variable speed pumped storage power generator of the above (3), the capacity of EX6 is limited by the capacity of the elements used in the converter, it is difficult to apply it to a large capacity converter, and the capacity of AESM is increased. There were problems such as the inability to start the AESM and the self-start of the AESM by the converter.

In the pumped storage power generator of the above (4), when the input / output setting device is operated, the electric power is immediately responded to the EX6 electrically by the output setting device 18, but since the guide vane operation is mechanical and slow, the power is temporarily reduced. The rotation speed responds in the opposite direction.
In addition, because early control is fed back with electric power,
Since the electric power is kept constant, the stability of the governor loop is degraded, the rotational speed may deviate from the variable speed range, and there is a case where there is a problem in response to the AFC signal.

The pumped-storage power generator of the above (5) requires the installation of a thyristor starting device at the time of pumping start, and when the self-start is performed only by the vector control in the EX6, the capacity of the EX must be increased. Economy.

The present invention has been made in order to solve the above-mentioned problems, and an object of the present invention is to provide a pumped-storage power generator capable of automatic frequency adjustment (hereinafter, abbreviated as AFC) during economical pumping operation. Aim.

[0026]

According to the first aspect of the present invention, there is provided a pumped storage power generator having an operation prohibition zone for preventing slippage below a certain value in order to avoid operation near zero slippage, and instructing the command rotation speed to be zero slippage. A device comprising a rotation correcting device for correcting a command rotation speed so as to operate outside the driving prohibited zone when entering a nearby driving prohibited zone, and a current restricting circuit for reducing an exciting current while passing through the driving prohibited zone. It is.

[0027]

The pumped storage power generator according to the first aspect of the present invention controls so as to prohibit operation near slippery zero, and performs control to narrow down the excitation current while passing through the operation prohibition zone.
Automatic frequency adjustment during pumping operation is possible even with a small capacity.

[0028]

[Embodiment 1] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of a variable-speed pumped-storage power generator showing one embodiment of the present invention. In the drawing, M denotes a winding type induction generator motor.
The secondary side is secondarily excited by the sliding frequency, and the finger is
AC-excited synchronous machine M (hereinafter, referred to as "operated")
AESM), 1 is the wound-type dielectric generator motor
Armature, 2 is a rotor (secondary coil) of the induction generator motor.
3) reversible pump turbine, 4 shaft, 5
6 is a transformer for a black converter, and 6 is a transformer as a converter for excitation.
Micro converter (hereinafter abbreviated as EX), 7 is rotating
Number detector, 8 is an inverter control circuit (cycloconverter)
Controller).

The EX 6 comprises an inverter 6a and a converter 6b. The inverter control circuit 8 includes a .SIGMA. Detection circuit 8a, a three-phase / two-phase conversion circuit 8b, an excitation system control command operation circuit 8c, and a q-axis control circuit 8d, d. Axis control circuit 8e, voltage,
It comprises a reactive power control circuit 8f, a two-phase to three-phase conversion circuit 8g, and the like.

Reference numeral 31 denotes a power setting device; 32, a rotation command circuit for avoiding slippage operation in a prohibited operation zone; 33, a current restricting circuit for restricting a current while passing through the prohibited operation zone; A rotation speed calculation circuit, 35 is a governor system control command calculation circuit, 36 is a governor, and 37 is a power detection circuit.

Next, the operation of the above embodiment will be described with reference to the characteristic curve of the pump turbine shown in FIG. In FIG. 2, the same parts as those in FIG. 5 are denoted by the same reference numerals, and redundant description will be omitted.

In FIG. 2, a range surrounded by lines L15 and L16 is a driving prohibited zone (for example, ± 0.5 Hz). As an example, if the head is 95% and the pump input command value of the AFC signal is intermediate between the points P17 and P18, the point P18
1 is determined by the rotation command circuit 32 of FIG. 1 and the governor-system control command calculation circuit 35 controls the rotation speed.
If the pump input command value is between the points P17 and P19,
The operation is performed so that the rotation speed at the point 19 is obtained. Further, when the vehicle is passing through the operation prohibition zone, the current narrowing circuit 33 controls the excitation current to be narrowed. By doing so, the rotation speed can be adjusted even if the capacity is small.

In FIG. 3, the horizontal axis is the slip (S) and the vertical axis is the EX capacity. L-1 is the theoretical characteristic, L-2 is the actual characteristic, L-3 is the capacity of EX6 when the slip is large, L-
Numeral 4 indicates a theoretical capacity when the driving prohibited zone slip is between lines L-8 and L-9, L-5 indicates a practical capacity with a margin added to L-4, and L-6 indicates a conventional capacity. Theoretical required capacity, L
-7 indicates a conventional realization capacity.

That is, since the slip zero is completely DC, 3
Since the currents that were ignited one after another in the phases and flowed evenly in each phase element continuously flow only in the one-phase element, theoretically when the slip was large, three times the heat capacity was required, At the implementation level, it is necessary to provide a further margin, so that the capacity must be very large, but according to the present invention, the capacity L-5
Therefore, it is possible to provide an economical variable speed pumped storage power generator.

Embodiment 2 FIG. Further, in the first embodiment, the control of the EX 6 is described in the case of the power feedback. However, in the rotation speed feedback, a rotation speed correction circuit may be added to the power feedback, or the power correction circuit may be added to the rotation speed feedback. Is also good. Also, the case where the EX 6 is composed of the inverter 6a and the converter 6b has been described. However, a cyclo converter may be used, and even in the case of variable speed power generation alone, a variable speed phase adjuster as an application of the variable speed machine, with a flywheel The variable speed generator has the same effect as the above embodiment.

[0036]

As described above, according to the first aspect of the present invention, it is possible to avoid the operation of the exciting converter near slippery zero and to reduce the exciting current while passing near the slippery zero. Therefore, even if the capacity of the excitation converter is small, automatic frequency adjustment during the pumping operation is enabled.

[Brief description of the drawings]

FIG. 1 is a block diagram of a pumped storage power generator according to an embodiment of the present invention.

FIG. 2 is a pumping operation characteristic curve diagram of the pump-turbine according to the embodiment apparatus of FIG. 1;

FIG. 3 is a characteristic curve diagram of slip versus excitation converter capacity.

FIG. 4 is a block diagram illustrating the principle of a conventional pumped storage power plant.

FIG. 5 is a pump operation characteristic curve diagram of a pump-turbine according to a conventional apparatus.

FIG. 6 is a block diagram of a conventional cycloconverter type variable speed pumped storage power generator.

FIG. 7 is a block diagram of another conventional cycloconverter-type variable speed pumped storage power generator.

FIG. 8 is a circuit diagram of a 12-phase non-circulating current type cycloconverter in a conventional device.

FIG. 9 is a block diagram of a conventional pumped storage power plant.

FIG. 10 is a response characteristic diagram in the case where the exciting converter is power-controlled.

FIG. 11 is a block diagram of a starting device in a conventional device.

[Explanation of symbols]

3 Reversible pump-turbine, 6 Excitation converter, 6a Inverter, 6b converter, 33 Current throttle circuit, 34
Optimal rotation speed calculation circuit (rotation speed correction device), 35 governor system control command calculation circuit, M AC excitation synchronous machine.

Claims (1)

(57) [Claims] 1. An AC excitation synchronous machine directly connected to a reversible pump-turbine, and an excitation converter for controlling a secondary voltage of the AC excitation synchronous machine to perform a variable speed operation of the AC excitation synchronous machine. In the pumped-storage power generator having, when the commanded rotation speed enters an operation prohibition zone near zero slip, a rotation speed correction device that corrects the command rotation speed to operate outside the operation prohibition band,
And a current restricting circuit for restricting an exciting current while passing through the operation prohibition zone.