JPH0880094A - Method and device for controlling variable speed generator motor - Google Patents

Abstract

PURPOSE: To control the quantity of excitation to its optimum value in the case of using a synchronous machine operation method when stopping or starting the pumping of a variable generator motor. CONSTITUTION: This variable speed generator motor has an excitation current arithmetic unit 16, which operates the ingredients of a torque current by active power adjustment operation and outputs them, an operation command operation set 20, which outputs a synchronous machine operation command, and a synchronous machine operation switching control circuit 15 which switches a variable speed generator motor from variable operation to synchronous operation, receiving the synchronous machine operation command outputted from the operation command operation set 20. The synchronous machine operation switching control circuit 15 is so controlled as to bring the components torque currents fixed to the value right before the switching to synchronous operation close to several different goal values, dependent upon whether the synchronous machine operation command is a synchronous machine operation command at stoppage or a synchronous machine operation command at start of pumping.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an operation control method and apparatus for a variable speed generator-motor, in which a secondary winding is AC-excited by using a frequency converter and a generator or an electric motor is operated at a variable speed. In particular, the present invention relates to an operation control method and apparatus for a variable-speed generator-motor, which is suitable for controlling the amount of excitation to an optimum value even when the synchronous machine operation method is used when the generator or motor is stopped or when pumping the electric motor.

[0002]

2. Description of the Related Art Conventionally, since a synchronous machine is generally used as a generator motor of a pumped-storage power generation system, only operation at a constant rotation speed can be performed, so that the efficiency of a pump turbine decreases due to the amount of power generation, the amount of pumped water, and the head. What to do
There was a problem that the load could not be adjusted during pumping operation.

Therefore, there has been proposed a variable speed pumped storage power generation system which solves the above problems by making the rotational speed of a pump turbine variable. This system is a system in which the secondary winding of a variable speed generator-motor (hereinafter referred to as variable speed machine) consisting of a large-capacity winding type AC excitation synchronous machine is secondarily excited, and the excitation frequency is adjusted. It realizes power generation and pumping operation at variable speed.

A major difference between such a variable speed generator-motor and the above-mentioned synchronous machine is that in the synchronous machine, a torque commensurate with the load torque (active power) is generated by a change in the internal phase difference angle. And the exciting current does not contribute to the torque, whereas the variable speed machine has 2
Since the secondary excitation current can be decomposed into a torque current component (also called active power component or q-axis component) and a magnetic flux direction current component (also called reactive power component or d-axis component) and controlled, It is possible to control active power and reactive power independently of each other (see, for example, JP-A-62-62).
-181698).

As described above, the method of controlling the exciting current in the two axes of dq axis to operate the AC excitation synchronous machine at a variable speed does not cause step out, is easy to be in parallel, and is capable of high-speed output control. There are merits.

On the other hand, when the generator motor is stopped or when pumping water is started, the torque rapidly changes, so that the rotation speed suddenly changes and stable operation cannot be performed.

Japanese Patent Laid-Open Publication No. 3-112398 discloses a method of operating a variable speed generator-motor, which keeps the rotation speed constant by a synchronizing force like a conventional synchronous machine. This operating method can be realized by fixing the frequency of the exciting current in order to apply the synchronizing force, omitting the calculation of the automatic active power regulator (APR), and fixing the value of the torque current component Iq.

[0008]

However, when the variable speed machine is started and stopped by using the synchronous machine operation method, the exciting current cannot be controlled to an optimum value because the torque current component Iq is fixed. An unstable phenomenon occurs due to excitation or underexcitation. For example, when the variable speed machine is stopped at a load of 100% and is stopped using the synchronous machine operation method, the torque current component Iq when switching from the variable speed operation to the synchronous machine operation method by the stop operation is the maximum value. The operating value Iq of the torque current component is fixed to this value.

In this state, the load factor (active power) is reduced by the operation of closing the guide vane, and at the same time, the power factor 1 control calculation for controlling the reactive power to zero constant is operated to reduce the magnetic flux direction current component Id. Is controlled in the direction
After the magnetic flux direction current component Id reaches the lower limit (for example, zero), the total excitation amount √ (Iq ² + Id ² ) becomes the fixed torque current component Iq and cannot be lowered below that. That is, when the stop operation is performed from an operating state with a large load, the torque current component Iq is fixed at a large value, and therefore the lower limit of the total excitation amount becomes excessive as the excitation amount of the no-load power factor 1. Therefore, the power factor 1 control does not work effectively, a phenomenon in which the reactive power cannot be controlled to zero constant occurs, and the load on the circuit breaker during disconnection increases.

When the synchronous machine operation method is used in the process of pumping up the variable speed machine, the torque current component Iq should be fixed at a small value in order to switch from the variable speed operation to the synchronous machine operation in the runner idling state where the torque is small. become.
After that, after the pushing down of the water surface is released and the priming water pressure that maximizes the torque change is established, the input sharply increases in the process of opening the guide vanes, but the torque current component Iq is fixed at a small value. Due to the insufficient excitation, the synchronization force becomes insufficient and the magnetic flux direction current component Id abnormally vibrates.

The present invention has been made in view of the above circumstances, and controls the amount of excitation to an optimum value when the synchronous machine operating method is used when stopping the variable speed generator-motor or starting pumping. It is an object of the present invention to provide an operation control method and device for a variable speed generator-motor that can be used.

[0012]

The above problem is that the torque current component of the secondary excitation current, which is fixed to a value immediately before switching to the synchronous machine operation mode when the variable speed generator-motor is stopped, is preset. It is solved by lowering to a predetermined value.

The above problem is also solved by obtaining the optimum target value of the torque current component of the secondary excitation current from the detected value of the system active power by a predetermined conversion formula when the variable speed generator-motor is stopped, and the synchronous machine operating system The problem can also be solved by adjusting the torque current component, which is fixed to the value immediately before switching to, to approach the target value.

The above problem is that the torque current component of the AC excitation current of the secondary winding, which is fixed to a value immediately before switching to the synchronous machine operation mode when the variable speed motor is pumped, is preset. It can also be solved by increasing the value to a predetermined value.

The above problem is also solved by obtaining a target value of the optimum torque current component of the secondary excitation current from a detected value of the system active power by a predetermined conversion formula when the variable speed generator-motor is pumped and starting the synchronous machine operation. The problem can also be solved by adjusting the torque current component fixed to the value immediately before switching to the system so as to approach the target value.

[0016]

When the variable speed generator motor is started and stopped by using the synchronous machine operation method, the torque current component of the AC excitation current of the fixed secondary winding is controlled to an optimum value, thereby overexciting. In addition, the unstable phenomenon due to underexcitation is eliminated, and as a result, the load on the circuit breaker at the time of disconnection can be reduced, and the pumping start can be controlled in a stable state.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows the overall configuration of an embodiment of a variable speed pumped storage power generation system to which the present invention is applied, and FIG. 2 shows the configuration of the main parts of the excitation control unit.

In FIG. 1, a primary terminal of a variable speed generator-motor 2 connected to a water turbine 1 is connected to a power system 5 via circuit breakers 3 and 8 and a main transformer 4. The secondary winding of the variable speed generator-motor 2 is supplied with a three-phase AC exciting current from a cycloconverter 6 as a frequency converter.

The cycloconverter 6 includes an exciting transformer 7
And a primary side of the main transformer 4 via a circuit breaker 8. The detected values of the active power P _L and the output voltage V _G are obtained by the power / voltage detector 11 via the instrument transformer 9 and the current transformer 10.

Phase detector 12 connected to generator motor 2
Detects a slip phase θs equal to the difference between the voltage phase of the power system and the rotation phase of the generator motor 2. The reference signal arithmetic circuit 13 connected to the phase detector 12 has a slip frequency ωs and a constant amplitude based on the slip phase θs, and
The fundamental wave signals cos θs and sin θs having the same phase and a phase difference of π / 2 with the next induced voltage are generated and output to the exciting current control device 14. An exciting current command computing device 16 is connected to the output side of the power / voltage detector 11,
The exciting current command calculation device 16 includes adders 17A and 17B.
And an adder 17A, a power adjustment calculator (APR) 18 which is an active power control means and a voltage adjustment calculator (AVR) 19 which is an output voltage control means connected to the output sides of the adders 17A and 17B, respectively. ing.

During normal variable speed operation, the exciting current command calculating device 16 calculates the torque current component Iq by the APR 18 so as to reduce the deviation between the command value P _{0 of} active power and the detected value P _L , and the AVR 19 The magnetic flux direction current component Id is calculated so that the deviation between the command value V ₀ of the output voltage and the detected value V _G is set to 0, and the obtained torque current component Iq is transferred to the magnetic flux via the synchronous machine operation switching control circuit 15. The direction current component Id directly,
Output to the exciting current control device 14.

The exciting current controller 14 comprises a current pattern calculator 22, a current control calculator 23 and an automatic pulse phase shifter 2.
4. Vector composition calculation from the torque current component Iq and the magnetic flux direction current component Id input from the excitation current command calculation unit 16 by the current pattern calculation unit 22 and the fundamental wave signals cos θs and sin θs input from the reference signal calculation circuit 13. Then, the current pattern I ₂ is calculated and output to the current control calculator 23.

The current control arithmetic unit 23 is a cyclone for zeroing the deviation between the current pattern I ₂ input from the current pattern arithmetic unit 22 and the exciting current detection value I _f detected by the current transformer 29. The control phase angle EC of the converter 6 is obtained and output to the automatic pulse phase shifter 24.

The automatic pulse phase shifter 24 controls the control phase angle E of the cycloconverter input from the current control calculator 23.
An ignition pulse is output to the thyristor of the cycloconverter 6 based on the power source voltage signal input from C and the transformer for instrument 28. The torque current component I of the secondary excitation current in the synchronous machine operating method according to the present invention will be described below.
The calculation method of q will be described. FIG. 2 shows a calculation block of the torque current component Iq in the synchronous machine operating method according to the present invention.

In FIG. 2, the operation command operation unit 20 is a circuit for judging the condition for using the synchronous machine operation method based on the operation command, and lowers the synchronous operation command at the time of stop, and the calculator 35.
To the calculator 34 when the pump operation is started
Also, the logical sum of both commands is output to the analog switch 30 and the reference signal calculation circuit 13. That is, in the process of stopping from the power generation operation, the input from the stop operation is dropped by the stop operation during the section from the time when the stop operation is started to the time when the load (active power) is lowered and the power is disconnected from the power system. In the section from the time when the input lower limit value is calculated to the time when it is disconnected from the power system, the synchronous machine operation command at stop is turned ON, and when the pumping is started, the runner idles by pushing down the water surface and parallels to the power system, then priming. From the time when the water pressure is increased to the rotational speed that is established, the push down of the water surface is released, the guide vane is opened to the specified opening, and the pumping start synchronous machine operation command is turned ON in the section until the time when the pumping operation is started. .

The analog switch 30 sends the torque current component Iq, which is the calculation result of the ARP 18, to the exciting current controller 14 as it is when the synchronous machine operation command from the operation command controller 20 is OFF, that is, during the normal variable speed operation. Output,
When the synchronous machine operation command is ON, that is, when the synchronous machine operation method is used, the output of the ARP 18 is disconnected and the setter 32
The torque current component Iq, which is the calculation result of the above, is output to the exciting current control device 14. At the same time, the reference signal calculation circuit 13 also switches the fundamental wave signal to a sine wave having the immediately preceding slip frequency.

The previous value holding circuit 31 is a circuit for holding the previously output torque current component Iq until the next calculation, and the value is output to the setter 32. Raising calculator 3
5 and the lowering calculator 34 are circuits that determine conditions for increasing or decreasing the value of the torque current component Iq held at the value immediately before switching to the synchronous machine operation mode, and the result is a raising command or a lowering command. It is output to the setter 32. That is, as shown in FIG. 3, the lowering calculator 34 lowers when the stop synchronous machine operation command is ON and the output of the comparator 36A is ON (that is, when the previous output Iq> the stop Iq target value). The command is output to the setter 32, and the raising calculator 34 is as shown in FIG. 4 when the pumping start synchronous machine operation command is ON and the output of the comparator 36B is ON (that is, when the previous output Iq <pumping start When the target value is Iq), an increase command is output.

As shown in FIG. 3, the Iq target value during stoppage is obtained from the active power detection value P _L by P _L × A + B. However, A, B
Are predetermined values set in advance. That is, the relationship between the active power detection value P _L and the Iq target value during stop is as shown in FIG. For example, when the operating point during variable speed operation of the variable speed machine is at the point P, and when switching to the synchronous machine operation mode by the stop operation from that point, first, the torque current component Iq of the secondary excitation current is fixed at the point P, At this time, Iq at stop
Since the target value is larger than the fixed torque current component Iq, the lowering operation is not performed. After that, when the active power detection value P _L decreases by closing the guide vane, the operating point eventually reaches point Q.

When the detected value P _{L of} active power further decreases, the fixed torque current component Iq becomes larger than the Iq target value at the time of stop, and the output of the comparator 36A in FIG.
And the lowering command is turned on.

Similarly, the Iq target value at the start of pumping is also obtained by P _L × C + D as shown in FIG. 6, and when the Iq target value at the time of stop becomes larger than the fixed torque current component Iq, the output of the comparator 36B is output. Is turned on, and the raising command is turned on. The Iq target value at the time of starting and at the time of stopping may be a fixed value set in advance. In this case, the stop Iq target value sets the optimum torque current component Iq with respect to the amount of excitation when disconnecting from the power system, and the Iq target value at the start of pumping starts the pumping operation and the variable speed operation. A torque current component Iq that is optimum for the amount of excitation when switching to is set.

The setter 32 adds a predetermined value set in advance to the previous value input from the previous value holding circuit 31 (increases) in accordance with the increase command or the decrease command input from the increase calculator 35 or the decrease calculator 34. (At the time of command) or subtraction (at the time of lowering command), the calculation result is output to the analog switch 30, and the value is output to the excitation current control device 14 as the torque current component Iq.

As described above, according to the present invention, even when the synchronous machine operating system is used in the process of stopping the variable speed machine, the value immediately after switching to the synchronous machine operating system after switching from the variable speed operation to the synchronous machine operating system. By lowering the operating value Iq of the torque current component fixed to the target value of the optimum torque current component Iq, the excitation amount can be controlled to the optimum value,
The unity power factor control can operate effectively.
That is, since the reactive power during disconnection can be controlled to 0, the load on the circuit breaker can be reduced.

Further, according to the present invention, even when the synchronous machine operation system is used in the pumping start process of the variable speed machine, the value immediately before switching to the synchronous machine operation system after switching from the variable speed operation to the synchronous machine operation system. The excitation amount can be optimally controlled by increasing the operating value Iq of the torque current component fixed to the target value of the optimum torque current component Iq, and from the lack of the synchronization force due to the lack of the excitation amount. There is no abnormal vibration of the generated magnetic flux direction current component Id, and stable pumping can be performed.

[0034]

As described above, according to the present invention, the excitation amount can be controlled to an appropriate value when the synchronous machine operation method is used when the variable speed machine is stopped or when pumping is started, so that the parallel disconnection can be achieved. This has the effect of reducing the load on the circuit breaker during operation and enabling stable operation when pumping water.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a variable speed pumped storage power generation system to which the present invention is applied.

FIG. 2 is a detailed block diagram showing a configuration of a main part of the embodiment shown in FIG.

FIG. 3 is a block diagram showing a specific configuration of the down calculator shown in FIG.

FIG. 4 is a block diagram showing a specific configuration of the raising arithmetic unit shown in FIG.

FIG. 5 is an explanatory diagram showing operating characteristics of the down calculator shown in FIG. 2;

FIG. 6 is an explanatory diagram showing operating characteristics of the raising calculator shown in FIG. 2;

[Explanation of symbols]

 1 Pump Turbine 2 Variable Speed Generator Motor 6 Cycloconverter 14 Excitation Current Control Device 15 Synchronous Machine Operation Switching Control Device 16 Excitation Current Command Calculator 18 Power Adjustment Calculator 19 Voltage Adjustment Calculator 20 Operation Command Operator 22 Current Pattern Calculator 23 Current control calculator 24 Automatic pulse phase shifter 31 Previous value holding circuit 32 Setting device 34 Raising calculator 35 Lowering calculator

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Taisho Ohno 3-3-22 Nakanoshima, Kita-ku, Osaka City, Osaka Prefecture Kansai Electric Power Co., Inc. (72) Hiroto Nakagawa 3-3, Nakanoshima, Kita-ku, Osaka City, Osaka Prefecture No.22 in Kansai Electric Power Co., Inc.

Claims (16)

[Claims] 1. An active power adjustment calculation is performed on a secondary winding of a variable speed generator motor connected to an electric power system so that a deviation between a command value and a detected value of output active power of the variable speed generator motor is zero. The torque current component obtained by performing the voltage adjustment and the magnetic flux direction current component obtained by performing voltage adjustment calculation so that the deviation between the voltage command value and the detection value of the output voltage of the generator motor becomes zero. In the operation control method of the variable speed generator-motor which is excited by the alternating excitation current obtained by vector synthesis, with the slip phase equal to the difference between the phase and the rotation phase of the generator-motor, the two axes of the torque current component and the magnetic flux direction current component are used. A variable speed operation method for performing current control and fixing the torque current component to a value immediately before excluding the active power adjustment calculation by excluding the active power adjustment calculation and at the same time the phase difference Calculation, the slip phase is switched to a sine wave having the slip frequency immediately before the phase difference calculation is excluded, and current control is performed like a synchronous machine, and the synchronous machine operation method is switched and operated according to predetermined conditions. An operation control method for a variable speed generator-motor, which is characterized by the following. 2. In the process of stopping the variable speed generator-motor from a power generation operation, the variable-speed generator-motor is operated by the synchronous machine operation method in a section from a time point when the stop operation is started to a time point when the output active power is lowered to be disconnected from the power system. The operation control method of the variable speed generator according to claim 1, wherein 3. In the process of stopping the variable speed generator-motor from the pumping operation, from the time when the input active power is lowered to the input lower limit value calculated from the head by the stop operation,
2. The operation control method for a variable speed generator-motor according to claim 1, wherein the operation is performed by the synchronous machine operating method in a section from the time when the guide vane opening is throttled to the parallel opening and the parallel is opened from the electric power system. . 4. A torque current component of an AC excitation current fixed to a value immediately before switching to the synchronous machine operation mode when stopping the variable speed generator motor using the synchronous machine operation method is preset. The operation control method for a variable speed generator-motor according to claim 2, wherein the operation speed is reduced to a predetermined value. 5. The optimum target value of the torque current component of the AC exciting current is obtained by a predetermined conversion formula from the detected value of active power when the variable speed generator-motor is stopped by using the synchronous machine operation method. 4. The operation control method for a variable speed generator-motor according to claim 2, wherein the torque current component fixed to a value immediately before switching to the operation mode is adjusted to approach a target value. 6. When the variable speed generator-motor is started to pump water, the water surface depression is released and the guide vanes are released from a predetermined point at the time point when the system speed is increased to a rotational speed that establishes priming water pressure after system parallelization in a runner idle state by water surface depression. The operation control method for the variable speed generator-motor according to claim 1, wherein the operation is performed by the synchronous machine operation method in a section up to the time point when the pumping operation is started up to the opening degree. 7. A torque current component fixed to a value immediately before switching to the synchronous machine operating mode when pumping and starting the variable speed generator-motor using the synchronous machine operating system up to a preset predetermined value. The operation control method of the variable speed generator-motor according to claim 6, wherein the operation speed is increased. 8. An optimum target value of a torque current component of an AC exciting current is obtained by a predetermined conversion formula from a system active power detection value when pumping and starting the variable speed generator-motor using the synchronous machine operating method, 7. The operation control method for a variable speed generator-motor according to claim 6, wherein the torque current component fixed to a value immediately before switching to the synchronous machine operation mode is adjusted so as to approach a target value. 9. A frequency converter for AC-exciting a secondary winding of a variable speed generator-motor connected to a power system, and a deviation between a command value and a detected value of output active power of the variable speed generator-motor is set to zero. Active power control means for obtaining the torque current component as much as possible,
Output voltage control means for obtaining a magnetic flux direction current component so as to zero the deviation between the voltage command value and the detection value of the output voltage of the variable speed generator-motor, and the torque current output from the active power control means and the output voltage control means. The vector and the magnetic flux direction current component are vector-synthesized with a slip phase equal to the difference between the voltage phase of the electric power system and the rotational phase of the generator motor.
In an operation control device for a variable speed generator motor, which has an exciting current control means for obtaining an exciting current value of a secondary winding and outputting it to the frequency converter, current control is performed by two axes of a torque current component and a magnetic flux direction current component. Variable speed operation and fixing the torque current component to a value immediately before excluding the active power adjustment calculation by excluding the active power adjustment calculation, and at the same time excluding the phase difference calculation and excluding the slip phase phase difference calculation Operation switching control means for performing switching control based on an operation command of the variable speed generator-motor, and switching between a synchronous machine operation in which current is controlled like a synchronous machine by switching to a sine wave having a slip frequency immediately before, and the external operation Synchronous start-up command for instructing synchronous machine operation when the variable speed generator-motor is stopped, or synchronous pumping start instruction for instructing synchronous machine operation when the variable speed generator-motor is pumped Operation control device for a variable speed generator-motor and having an operation command operating means for outputting operation command. 10. In the process of stopping the variable speed generator-motor from the power generation operation, the operation command operation means stops in a section from a time point when the stop operation is started to a time point when the output active power is lowered to disconnect from the power system. The operation control device for the variable speed generator-motor according to claim 9, wherein a time synchronous machine operation command is output to the operation switching control means. 11. In the process of stopping the variable speed electric motor from the pumping operation, the guide vane opening degree is opened from the time when the input active power is lowered to the input lower limit value calculated from the head by the stop operation. 10. The variable speed power generation according to claim 9, wherein the stop command synchronous motor operation command is output from the operation command operation means to the operation switching control means in a section up to the time of disconnection from the throttle power system up to 10 degrees. Operation control device for electric motors. 12. The operation switching control means presets a torque current component of an alternating excitation current fixed to a value immediately before switching to the synchronous machine operation when the variable speed generator-motor is stopped by the synchronous machine operation. The operation control device for a variable speed generator-motor according to claim 10 or 11, characterized in that the operation is controlled to a predetermined value. 13. The operation switching control means obtains an optimum target value of a torque current component of an AC exciting current from a detected value of active power by a predetermined conversion formula when the variable speed generator motor is stopped by a synchronous machine operation. The operation control device for a variable speed generator-motor according to claim 10 or 11, wherein the torque current component fixed to a value immediately before switching to the synchronous machine operation is adjusted to approach a target value. . 14. When the variable speed generator-motor is started to pump water, the water pressure is released and the guide vanes are released from a predetermined point at the time when the system speed is increased to a rotational speed that establishes priming water pressure after system parallelization in a runner idling state by water pressure depression. 10. The pump according to claim 9, wherein a pumping start-up synchronous machine operation command is output from the operation command operation means to the operation switching control means in a section up to the time point when the pumping operation is started up to the opening degree. Operation control device for variable speed generator-motor. 15. The operation switching control means presets a torque current component fixed to a value immediately before switching to the synchronous machine operation when pumping the variable speed generator-motor by the synchronous machine operation. The operation control device for a variable speed generator-motor according to claim 14, wherein the operation control device is increased to a value. 16. The operation switching control means sets a target value of an optimum torque current component of an AC exciting current according to a predetermined conversion formula from a system active power detection value when pumping and starting the variable speed generator-motor by synchronous machine operation. 15. The operation control device for the variable speed generator-motor according to claim 14, wherein the torque current component fixed to a value immediately before switching to the synchronous machine operation mode is adjusted to approach a target value.