JP3073719B2 - 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. 3 shows, for example, Japanese Patent Application Laid-Open No. Sho 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. AC excitation synchronous machine (hereinafter abbreviated as AESM) operated with the applied power, 1 is an armature of the wound-type induction motor, 2 is a rotor (secondary coil) of the induction motor, and 3 is reversible. 4 is a shaft, 5 is a shaft, 5 is a transformer for a cycloconverter, 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. is there.

FIG. 4 shows the pumping direction operation characteristics of the above-mentioned variable speed pumping power generator. The vertical axis represents the pump input in%, and the horizontal axis represents 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. 4, 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. 5 is a cycloconverter type variable speed pumping system shown in, for example, "Exciting System Protection System for Variable Speed Pumping Power Generation System", 11th-55th and 11th-56th, IEEJ National Convention 1991. FIG. 4 is a block diagram of a power generator, in which the same components as those in FIG. 3 are denoted by the same reference numerals, and redundant description will be omitted. In FIG. 5 , 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 on the 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 next 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. 6 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. 3, the same parts for a repeated explanation thereof are denoted by the same reference numerals. In FIG. 6 , 13 is an instrument current transformer, and 14 is an instrument transformer. FIG. 7 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, when the synchronous generators are operated in parallel, if the three elements of the frequency, the voltage magnitude, and the phase of the two generators do not match, disturbance occurs at the same time when the parallel generators are turned on. 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 speed detector (for example, a resolver) 7 of the rotor 2 of the AESM, a generator output current by the instrument current transformer 13, and a generator output voltage by the instrument transformer 14. Are controlled by the cyclo-converter controller 8 which receives the control information and the like as the control elements, and the AESM is system-controlled so that the finally set power and the optimum rotational speed are obtained.

(4) FIG. 8 shows, for example, IEEJ, Vol.
FIG. 13 is a block diagram of the pumped-storage power plant shown in FIG. 12, No. 62, pp. 210, and 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 setting device,
9 is an input / output control servo of the pump turbine 3, 20 is a governor,
21 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. 9 (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 10 is a block diagram showing a starting device for a variable speed pumped storage power generation apparatus shown in Figure 8, the duplicated description thereof is omitted with like reference numerals denote the same parts as FIG. Figure 1
At 0 , 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, and the water level of the pump turbine 3 is first pushed down by a start command, and then the starting breaker 27 is turned on. Then, starting is started by the thyristor starting device 30.
The speed is increased by the thyristor starting device 30, and the excitation during the speed increase is E
When DC or low frequency (slip 3% or less) excitation is performed by X6, and when the vehicle is accelerated to near the synchronous speed, the starting circuit breaker 27 is released and EX6 is controlled to perform uniform speed control.
Synchronous input by the circuit breaker 23. 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, FIG pumping power generator and Fig 1
As a conventional example related to the starting device of 0, JP 60-2
JP-A-01078, JP-A-2-111300 and JP-B-3-51910.

[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 to solve the above-mentioned problems, and has as its object to obtain a small, economical and simple pumped-storage power generator.

[0026]

A pumping power generator according to the present invention comprises an exciting converter for controlling a rotor of an AC exciting synchronous machine comprising a multi-phase parallel multiplex type inverter and a converter. Is converted by a three-phase to two-phase conversion circuit in order to execute the current balance control independently for each parallel circuit with the two-phase components of the d and q axes. Each parallel multiplex inverter is controlled by three-phase conversion independently by a two-phase to three-phase conversion circuit, and the converter is controlled by a converter control circuit.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below. Embodiment 1 FIG. FIG. 1 is a block diagram of a variable-speed pumped-storage power generator showing a first embodiment of the present invention. In the figure, M designates secondary excitation of a secondary side of a wound induction motor with a sliding frequency and a variable speed. AC excitation synchronous machine (hereinafter abbreviated as AESM) operated with the supplied electric power, 1 is an armature of the wound-type induction motor, 2 is a rotor (secondary coil) of the induction motor, and 3 is an induction motor. Reversible pump turbine, 4 is a shaft, 5 is a transformer for a cycloconverter, 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. It is. The EX 6 is an inverter 6a, a converter 6b, a DC link capacitor 6
c, an excessive DC voltage detection circuit 6d, a GTO 6e for protection, and a short-circuit resistor 6f.

Reference numerals 46, 47, 48 and 49 denote current detection circuits for detecting the input / output current of EX6,
a-2 is a three-phase to two-phase (2φ, d, q-axis component) conversion circuit, 51 is an operation command circuit, 52a-1, 52a-2 are two-phase to three-phase conversion circuits, 53a-1, 53a -2, an inverter control circuit for controlling two sets of parallel multiplexed inverters 6a-1, 6a-2; 54, a converter control circuit for controlling two sets of parallel multiplexed converters 6b-1, 6b-2;
Reference numeral 5 denotes a head detection circuit, and reference numeral 84 denotes a controller.

[0029] Next, the operation will be described. First, the inverter control circuits 53a-1 and 53a-2 control the inverters 6a-1 and 6a so that the output of the AESM becomes the power, the reactive power, the voltage, and the optimum rotation speed commanded by the operation command circuit 51.
a-2 is PWM (pulse web modulation)
Control.

The inverters 6a-1, 6a-
Independently of converter 2, converter control circuit 54 converts the converter output voltage to a power factor of converters 6b-1 and 6b-2 of 1.0.
Is controlled so as to approach. That is, as shown in the GTO thyristor multiphase voltage source excitation converter of FIG. 7 , the voltage waveform is PWM controlled, so that the inverter control circuit 53a
-1, 53a-2 are simplified, and at the same time, the protection circuit and the like (not shown) of the GTO circuit are also simplified.

It should be noted, conventional cycloconverter for which was a 12 natural commutation mode of a non-phase circulating current, as shown in FIG., The power factor control was not performed independently. Therefore, the power factor was as low as about 0.3. Further, since the input / output rotation speed control is controlled by the cycloconverter, the circuit cannot be avoided from becoming complicated, and it is difficult to say that the controllability is also favorable.

In order to increase the capacity of AESM, EX is required.
Since the six inverters 6a-1 and 6a-2 are multiplexed in parallel, the parallel multiplexing control requires current balance control between the multiplexed inverters. In this case, too, an independent current balance is provided for each parallel circuit. Since PWM control is enabled by the circuit, controllability is facilitated.

Further, after three-phase to two-phase conversion circuit 50a-1,50a-2 3-phase two-phase converted detects the output current of the parallel circuit by the current detecting circuit 46 and 47 for each parallel circuit, wherein Current balance control is performed by a current balance circuit, and the balance control is performed on the d and q axes for each parallel circuit in combination with the output of the inverter control circuits 53a-1 and 53a-2. The conversion circuits 52a-1 and 52a-2 use 3
And the inverters 6a-1 and 6a-
2 is subjected to PWM control, so that controllability is also improved.

In general, regarding the effectiveness of controlling the d and q axes, see the Institute of Electrical Engineers of Japan, July 11, 1986, Semiconductor Power Conversion Workshop, SPC-86-51, "Secondary Excitation Induction Machine". Examination of power and reactive power control using ”.

As described above, according to the first embodiment,
Since the exciting converter is composed of a multi-phase parallel multi-voltage type inverter, a converter and a converter, the output current of this inverter is independently supplied to each parallel circuit via a three-phase to two-phase converter, and d, q After being converted and further subjected to current balance control by a current balance circuit for each parallel circuit, the parallel circuit is again independently subjected to a two-phase to three-phase conversion circuit and returned to three phases, and an inverter for each parallel circuit is returned. By being controlled by the control circuit, it can be applied to increase the capacity.

[0036] Embodiment 2. In the first embodiment, the forced commutation type multi-phase parallel multiple voltage type has been described as an example of the secondary excitation converter. However, the number of phases is three or more and the number of parallel multiplexes is two.
With the above, the same effects as in the above embodiment can be obtained.

In addition, not limited to pumped storage power generators,
The present invention may be applied to an SM application plant, for example, a flicker prevention system using a phase shifter or a flywheel generator, and has the same effects as those of the above embodiment.

[0038]

As described above, according to the present invention, the exciting converter is constituted by the forced commutation type multi-phase parallel multiplex inverter and the converter, and the current balance between the parallel inverters is independent for each parallel circuit. In addition, since the control is performed on the d and q axes, the controllability of the inverter is improved and the conversion efficiency of the AC excitation synchronous machine is also improved, thereby providing a compact, economical and simple variable speed pumped storage power generator. There is an effect that can be done.

[Brief description of the drawings]

FIG. 1 is a block diagram of a pumped storage power generation device according to a first embodiment of the present invention.

FIG. 2 is a block diagram of a converter for GTO multiphase voltage source excitation in the apparatus of the embodiment of FIG. 1;

FIG. 3 is a block diagram illustrating the principle of a conventional pumped storage power plant.

FIG. 4 is a pumping operation characteristic curve diagram of the pump turbine according to the conventional apparatus of FIG. 3 ;

FIG. 5 is a block diagram of a conventional cycloconverter type variable speed pumped storage power generator.

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

FIG. 7 is a circuit diagram of a 12-phase non-circulating current type cycloconverter in a conventional device.

FIG. 8 is a block diagram of a conventional pumped storage power plant.

FIG. 9 is a response characteristic diagram when the power of the excitation exchanger is controlled.

FIG. 10 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, 7 Speed detector, 50a
-1, 50a-2, 63, 64, 65 three-phase to two-phase conversion circuit, 52a-1, 52a-2 two-phase to three-phase conversion circuit,
53a-1, 53a-2 Inverter control circuit.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H02P 9/00

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, a multi-phase parallel multiplex type inverter and a converter constituting the exciting converter, and a voltage, current and an output signal of a rotational speed detector and a command detected from an output side of the AC exciting synchronous machine are transmitted. A three-phase to two-phase conversion circuit for independently performing d and q conversion of the output current of each of the parallel multiple voltage inverters for each parallel; A current balance circuit for independently controlling the current balance between multiple inverters for each parallel; and a d and q axis independently for each parallel circuit from the current balance circuit for each parallel and the output of the controller. Balance system A two-phase to three-phase conversion circuit for controlling each parallel multiplex inverter, each parallel multiplex inverter control circuit for controlling the output current of the inverter, and the converter for generating a DC voltage of the inverter.
And a converter control circuit .