JPS62236395A - Operation control system for variable speed pumpingup generator plant - Google Patents

Abstract

PURPOSE:To stably control a variable speed pumping-up generator plant to a target value at AFC operation time by operating it with a rotating speed determined by a power command value and an effective head and a governor valve opening. CONSTITUTION:A block 25 obtains an optimum valve opening and an optimum rotating speed by an effective head H and an output command P0. The output of a speed governor 24 which responds to the difference between the optimum rotating speed and the actual rotating speed N is applied to an output command value P0 in the block 25. The optimum valve opening is applied to a servo system 14 to become the valve opening of a governor. A secondary winding phase angle calculator 16 calculates a phase angle by the effective power, actual rotating speed and the output of the block 25 to apply it to a setter 17 for setting the exciting amount of a secondary circuit.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to an operation control method for a variable speed power generation system that can be operated at any rotation speed using an induction machine with secondary excitation.
In particular, the present invention relates to an operation control method suitable for stably controlling to a target value during AFC operation of power generation and pumping.

[Background of the invention]

In conventional pumped storage power generation systems, the efficiency of the system changes due to the inability to adjust the load during pumping, changes in the power required by the grid during power generation and pumping operations, and changes in the head during pumping. There were drawbacks.

For this reason, research is underway to operate the above system at maximum efficiency, regardless of power generation or lift. In order to achieve the above objectives, by using a so-called variable speed power generation system in which the conventional pumped storage generator, which is a synchronous material, is operated with an induction material with secondary excitation, the system achieves maximum efficiency regardless of power generation or pumping height. From the perspective of making it possible to operate the vehicle, research is underway to make this possible. However, regarding such a system, there is a paper 4553r "Variable Speed Operation Characteristics of Large Capacity Synchronous Motor" at the 1981 National Conference of the Institute of Electrical Engineers of Japan, etc., but a specific control method % formula % [Object of the Invention] The present invention It is an object of the present invention to provide an operation control method for compensating for the above-mentioned drawbacks and stably controlling to a target value during AFC31ij rotation in a variable speed pumped storage power generation system that operates with high efficiency under various operating conditions of pumping and power generation.

[Summary of the invention]

This application proposes a method for stably controlling to a target value during AFC operation of pumping and power generation in a variable speed pumped storage power generation system. The operating conditions for obtaining a desired power generation power are determined by the relationship between the effective head per rotation speed and the governor valve opening degree. Among these, the efficiency of this system is determined by the rotation speed and valve opening degree. For this reason.

When the effective head and rotation speed are determined, the valve opening degree is controlled to achieve maximum efficiency. On the other hand, the above-mentioned rotation speed is determined by the difference between the water qt large input generator output.

Therefore, it is necessary to control the phase angle of the secondary excitation voltage so that the generator output matches the command value. In this system, which is an induction machine with secondary excitation, the phase angle of the secondary excitation voltage is controlled in this way, and the governor valve opening degree is also controlled.

Specifically, the phase angle is controlled using the difference between the power command value and the actual value, and based on the difference between the target rotation speed and the actual rotation speed, the effective head, and the power command value, The valve opening is controlled to a predetermined optimum valve opening, and the engine is operated at the rotational speed and puff valve opening determined from the power command value and the effective head.

[Embodiments of the invention]

FIG. 1 shows an outline of a variable speed power generation system, and both the negative and secondary sides are composed of three-phase windings.

In the same figure, 1 indicates the stator and 2 indicates the rotor 658-5c
68 to 6c indicate the a, b, and a phase windings of the stator, and the a, b, and Q phase windings of the rotor. Furthermore, if the rated frequency is f and the slip is S, then the rotor speed is! (1-g),
By exciting the excitation winding of the rotor 2 at the frequency S, the rotating magnetic field of the rotor rotates with zero slip (synchronous speed).

It becomes the same as the speed of the rotating magnetic field of the stator. 7 indicates a measurement unit that measures the rotation speed of the rotor, and from this output, 3 detects the slip frequency, and 4 generates a voltage according to the slip frequency to excite the secondary winding. There is. By doing so, even if the motor is operated at any rotational speed, a voltage of the system M frequency can always be generated in the armature winding. That is, in the example of FIG. 1, the rotating magnetic field of the rotor is.

f (1-s) +f-s=f (
1), and the output at the rated frequency can be obtained regardless of slippage. In this system, the gist of the present application is to devise a system that can stably control the rotation speed to a target value at any rotation speed during AFC operation for pumping and power generation.

FIG. 2 shows a specific example of this system, and shows a case where a variable speed machine is connected to a grid and is in operation.

Reference numeral 10 indicates an electric power system, and 1 and 2 indicate the same stator and rotor as in FIG.

The output command Po is given to the 1-phase angle calculation section 16. On the other hand, the effective head H and the output command P are determined in block 15 according to a predetermined function.

From this, the optimum valve opening degree and optimum rotation speed are determined.

The output of the speed governor 24, which responds to this output according to the difference between the optimum rotational speed determined from the effective head H and the output command PO and the actual rotational speed, is converted into electric power via block 26 and converted into an output command value at block 25. Added, Block 1
The optimum valve opening obtained in step 5 is given to the servo system 14,
With a time delay, the valve opening of the governor becomes 13. 12 is the waterwheel military department. Due to this water wheel characteristic, the rotor 2 of the variable speed machine rotates. Reference numeral 11 indicates a speed generator, and the speed is detected by the output of this generator. Reference numeral 19 indicates a current transformer, 20 indicates a voltage transformer, and 21 calculates active power based on the outputs of the current transformer 19 and the voltage transformer 20. 616 is a phase angle calculation unit of the secondary winding. Yes, 21 outputs and block 2
The phase angle is calculated from the output of 5. 17 is a setting section for setting the amount of excitation of the secondary circuit, 18 is a voltage adjustment section for controlling the voltage value of the amount of excitation, 23a, 23b, 23
c is a phase shift unit that shifts the excitation amount set in step 17 to the a, b, and Q phases. 22a, 22b.

22c is the excitation amount phase-shifted by the phase shifters 23a to 23c;
This is an excitation tube line that excites the b and c phases. In this way, control is performed by calculating the phase angle of the secondary winding from the difference between the power control command value and the actual output. On the other hand, the valve opening degree 13 is controlled to be the optimum valve opening degree based on the effective head and rotation speed.

The present invention attempts to establish an optimal system during power generation operation, as shown in FIG.

Hereinafter, embodiments of the present invention will be explained in more detail with reference to FIG. FIG. 3 shows an example in which a so-called variable speed power generation system Gl, which can be operated at any rotation speed using an induction machine with secondary excitation, is connected and operated to the grid 10 via a power transmission line.

The power transmission ML includes a voltage transformer PT1. current transformer CT s
is installed.

Generally, Francis turbines are used for pumped storage generators.
The relationship between water turbine output and efficiency is shown in Figure 4.

In this figure, the horizontal axis represents the water turbine output, the vertical axis represents the efficiency, and the number of rotations is shown as a parameter. PI and P2 are the water turbine outputs, η1. η2 is the efficiency, Ns, Nz are the rotation speed,
Yl and Y2 indicate the valve opening degree, and the output Pl is the rotation speed Nl
, at the valve opening Yz and the output P2, the rotation speed N2. Maximum efficiency η1 for each output at valve opening Y2. This shows that η2. As described above, the rotational speed at which efficiency is maximized varies depending on the output, and the gist of the present application is to operate at these points of maximum efficiency.

In FIG. 3, when the variable speed pumped storage power generation system G1 is given a power command Po required for the generator from the operating end T, the variable speed pumped storage power generation system G1 operates with high efficiency, taking into account the characteristics of the generator and the effective head H. In order to achieve this, the opening degree of the governor valve of the water turbine is determined by the control control section C from the rotational speed N of the generator determined from the speed generator 11 and the effective head H, and the operation is performed to meet these values. need to be controlled. When a command to change the output of one generator is given in such a state, the effective head is changed using a method given in advance.

Based on the generator output, determine the governor valve opening to maximize the efficiency of the generator, and control the rotation speed to achieve these values.The difference between the rotation speed and the target value is shown in Figure 2. Like,
This will be added to the output command value for control, resulting in efficient operation.

On the other hand, the deviation of the rotation speed of one generator from the rated value is caused by the excitation circuit E
By using the slip frequency as the information on x, an output at the rated frequency can be obtained as described above.

Next, a specific example of secondary excitation will be described. As shown in FIG. 2, the three-phase secondary excitation winding is constructed as follows.

That is, one phase angle Δδ of the function for obtaining the excitation amount of the aHby G phase is controlled by a command given from the operating end T in FIG. If the a, b, and c phase voltages of the secondary excitation circuit are V z a e V t b e V g c +, then the following is given. Here, E is a voltage value determined by slip and the operating state of the variable speed machine, δ0 is a phase angle determined by the operating state of the variable speed machine, and Δδ is a phase angle controlled by the output of the control command section.

When performing control using the above formula, voltage E is used for reactive power control commands, and voltage E is used for active power control commands.
It may be controlled by the phase angle Δδ.

The present application aims to provide stable control during AFC operation of power generation in the above system.

Therefore, in the above configuration, the phase angle (Δ
δ), it is necessary to adjust the rotation speed and electric power to target values, and to control the valve opening degree so as to achieve optimum efficiency. For this purpose, active power is used as information for controlling one phase angle. That is, the phase angle Δδ is Δδ=kx(P-Pa)dt+kp(-Po)
(3). Here, Po: target value of active power,
P: actual value of active power, kt, kp: constants.

On the other hand, pump input is controlled by adjusting the valve opening of the governor. That is, as shown in FIG. 2, the optimum valve opening degree is set in advance based on the actual values of the effective head and rotational speed.

Controls the governor valve opening.

In block 24, as shown in FIG. ), and add their outputs in block 35.

〔Effect of the invention〕

According to the present invention, there is a function to control the valve opening of the governor based on the actual values of the effective head and speed, and a function to control the phase angle of the secondary excitation voltage based on the difference between the target value and the actual value of the electric power. Equipped with both, in AFC operation during pumping,
Since the target value can be stably controlled, the effect on stability is extremely large.

Furthermore, in pumped storage power generation systems that generate electricity during the day and operate as pumped storage at night to cover the fluctuating load of the grid, it is possible to operate efficiently with the power determined by the grid even during pumped storage operation, which has an extremely large economic effect. .

[Brief explanation of drawings]

Figure 1 is an overview of the principle of variable speed pumped storage power generation system, 11'
Fig. 2 shows an overview of variable speed pumped storage power generation, Ute A (7) control, Fig. 3 shows an example of the embodiment of the present application, and Fig. 4 shows an example of the relationship between the output and efficiency of a variable speed machine. , FIG. 5 is a diagram showing a specific embodiment of the present application. Ex...excitation circuit, G1...variable speed power generation system,
L...Power transmission line, ■...Governor valve, C...Control command unit, T...Operation end, 1...Stator, 2...Rotor, 3...Slip detection unit , 4... Voltage generating section, 5a~
5c... Stator a. b, c phase winding, 6 a ~ 6 c - rotor a, b, c
Phase winding, 7... Rotation speed measuring section, 10... System, 11
... Speed generator, 12... Water turbine section, 14... Servo system, 15... Delay circuit, 13 Governor valve, 16...
Secondary winding phase angle calculation section, 17... Secondary winding excitation amount setting section, 18... Voltage adjustment section, 19... Current transformer, 2
0... Voltage transformer, 21... Effective receiving force deriving unit, 22
a. 22b, 22cm secondary excitation a, b, Q phase winding, Po.
...Output command value, N...Speed, 23a, 23b. 23c... Phase shift section, 24... Speed governor, 25
...Kaya 1 Day HPσ $3 Eye Kaya 4- Prisoner F2 F.

Claims (1)

[Claims] 1. In a variable speed power generation system that operates an induction machine with secondary excitation at an arbitrary rotation speed, a function of performing excitation control based on a power command value and the output of the induction machine, and a function of controlling the excitation by the power command value and the output of the induction machine, and the rotation speed, power command value, and head of the induction machine. An operation control method for a variable speed pumped storage power generation system, comprising a function of determining a deviation from a more determined optimum rotation speed, and a function of controlling a power command value so that the deviation becomes zero.