JP2652033B2 - Operation control method of variable speed pumped storage power generation system - Google Patents

Description

Description: BACKGROUND OF THE INVENTION The present invention relates to an operation control method of a variable speed pumped-storage power generation system that can be operated at an arbitrary rotation speed by a winding type induction machine, and particularly to an AFC (automatic frequency adjustment) operation. The present invention relates to an operation control method suitable for stably controlling to a target value so as to obtain optimum efficiency during pumping operation.

[Prior Art] and [Problems to be Solved by the Invention] Conventional pumped-storage power generation systems are incapable of adjusting the load during pumping, and during power generation operation and pumping operation, changes in power generation required by the system and There is a drawback that the efficiency of the power generation system changes due to the head at the time of pumping.

For this reason, research is being conducted to operate the above system at the highest efficiency regardless of the generated power and the head. In order to achieve the above object, a synchronous machine conventionally used as a pumping generator is operated by an induction machine with secondary excitation (that is, a winding type induction machine), that is, for realizing a so-called variable speed power generation system. Research is ongoing.

 Here, the variable speed power generation system will be described.

FIG. 5 shows the principle of the variable speed power generation system. In Figure 5, G ₁ is wound induction machine (hereinafter, referred to as variable speed machines.), 1 stator, 2 denotes a rotor. 5a-5c
Are the windings of the respective phases a, b, and c of the stator 1, and 6a to 6c are the windings of the rotor 2
The winding of each phase is shown. Assuming that the rated frequency is f and the slip is s, the speed of the rotor 2 is f (1-s). By exciting the secondary windings 6a to 6c of the rotor 2 at the frequency of the slip s, the rotor The rotating magnetic field 2 has a slip s of zero (periodic speed) and is equal to the rotating magnetic field speed of the rotor and the stator 1. The rotational frequency of the rotor 2 is measured by the measuring unit 7, the slip frequency is detected from the output by the slip frequency detector 3, and the frequency / voltage converter 4 generates a voltage corresponding to the slip frequency. Excitation is given to the secondary windings 6a to 6c. By doing so, the secondary windings 6a to 6c can always generate a voltage of the system frequency even when the operation is performed at an arbitrary rotation speed. That is, in the example of FIG. 5, the rotating magnetic field of the rotor 2 becomes f (1−s) + fs · f = f (1), and the output of the rated frequency is obtained regardless of the slip s. Become.

Showa 59 as a literature on the above variable speed power generation system
IEEJ National Convention (held March 28-30, 1984)
No. 553 "Variable speed operation characteristics of large capacity synchronous motor", but this document does not disclose any specific control method.

An object of the present invention is to provide an operation control method capable of controlling a target power value with high efficiency and stability in an automatic frequency control (hereinafter, referred to as AFC) operation in a variable speed pumped storage power generation system. I do.

[Means for solving the problem]

In order to achieve the above object, the present invention relates to an operation control method for a variable speed pumped-storage power generation system that operates a wound-type induction machine connected to a water turbine in response to a change in system load. And controlling the phase angle of the exciting current of the induction machine to reduce the deviation between the actual input power value and the given power control command. Based on the correlation between the set input power value and the governor valve opening,
A governor valve opening corresponding to a given lift command and the actual input power value is determined, and while operating the governor valve of the turbine to the determined governor valve opening, a change in the power control command is delayed. Features.

[Action]

In the variable-speed power generation system, operating conditions for obtaining an arbitrary power generation are determined by the relationship between the head, the rotation speed, and the governor valve opening. Among these, the efficiency of the variable speed power generation system is determined by the rotation speed of the induction machine and the governor valve opening. this house,
Since the number of revolutions is determined by the difference between the input and output of the induction machine, the governor valve opening is controlled so that the maximum efficiency is achieved when pumping and input are determined. On the other hand, the above rotation speed is determined by the difference between the pump input and the induction machine output. For this reason, it is necessary to control the phase angle of the secondary excitation voltage so that the output of the induction machine matches the specified value. In the variable speed power generation system according to the present invention using the winding type induction machine which is the induction machine with the secondary excitation, the phase angle of the secondary excitation voltage is controlled so as to always obtain the optimum efficiency, and the governor valve is opened. Control the degree.

Here, a Francis turbine is generally used as the pumping generator, and the relationship between the turbine output and the efficiency is shown in FIG. FIG. 3 shows the turbine output on the horizontal axis, the efficiency on the vertical axis, and the rotation speed as a parameter. P ₁ , P
₂ is the turbine output, η ₁ and η ₂ are the efficiency, N ₁ and N ₂ are the rotation speeds,
Y ₁ and Y ₂ indicate the valve opening. Rotational speed N ₁ at the output P _1, the valve opening degree Y ₁
In the rotational speed N _2, the valve opening degree in the output P ₂ is Y _2, shows to be a maximum efficiency eta _1, and eta ₂ at each output.

In addition, since the power control command often changes in a step-like manner, the phase angle of the exciting current of the wound-type induction machine changes in a step-like manner in response thereto, and the output of the wound-type induction machine greatly changes. As a result, the rotational speed may become unstable. However, according to the present invention, since the change of the power control command is delayed, such instability can be suppressed.

Thus, according to the present invention, it is possible to stably control the target power while maintaining the optimum efficiency.

〔Example〕

Next, an embodiment of an operation control method for a variable speed pumped storage power generation system according to the present invention will be described with reference to the drawings.

First, an outline of the variable speed pumped storage power generation system is shown in FIG. The system variable transmission G ₁ is operated by the hydraulic turbine 13, power system output power of the variable speed machine G ₁ is via the transmission line L
Supplied to 10.

In FIG. 1, an optimal valve opening Y of the governor valve 12 is calculated based on a lift command H given from a console T and a rotation speed N from a rotation speed detector 11, and the opening control of the governor valve 12 is performed. Do. On the other hand, based on the power control command P ₀ given from the console T, the active power calculation unit 21 calculates the active power from the values detected by the voltage transformer (PT) 20 and the current transformer (CT) 19, and the active power considering the number of revolutions N by performing control by applying an excitation voltage v to the exciting circuit E _x of the variable transmission G ₁ and. That is,
The output control is performed at a certain pumping point F.

Next, FIG. 2 shows a more specific example of the variable speed pumped-storage power generation system shown in FIG. Note that the same reference numerals are used for the portions that overlap with FIG. In FIG. 2, when a head command H is given, the optimum valve opening calculating section 25 converts the head command H into a parameter based on the characteristics (FIG. 4) of the predetermined input P and the governor valve opening Y. The governor valve opening Y corresponding to the input P is output. For example, in FIG. 4, the governor valve opening to the Y ₁ and Y ₂ if you change the input P ₁ to P _2. This governor valve opening Y is given to the servo system 14. The servo system 14 adjusts the governor valve 12 by giving an operation amount corresponding to the input governor valve opening Y to the governor valve 12. Thus, the water wheel 13 is controlled according to the head command H.

On the other hand, if the power control command P ₀ is given in Figure 2, the power control command P ₀ is input to the phase angle calculation unit 16 via the delay circuit 15. The delay circuit 15 controls the power control command P ₀
There order given stepwise, as variable transmission G ₁ secondary winding 6a~6c variable speed machine when used for controlling the excitation voltage v of
Since the output of G ₁ is made that varies greatly, it is intended to delay in order to prevent it. Power control command P ₀ which has passed through the delay circuit 15 is input to the phase angle calculation unit 16. On the other hand, the active power P is determined by the voltage and current of the system from the transformers 19 and 20 by the active voltage calculation unit 21 and input to the phase angle calculation unit 16.

The phase angle calculator 16 calculates the excitation voltage v applied to the secondary windings 6a to 6c. That is, the phase angle Δδ among the functions for obtaining the amount of excitation of each phase of the secondary windings 6a to 6c is controlled by the command given by the console T. A secondary winding 6 a to 6 c, b, and c phase voltages v _fa, v _fb, When v _fc, Is given. Here, E is a voltage value determined by the operating state of the slip and variable speed motor, [delta] ₀ is the phase angle determined by the operating state of the variable speed machine, .DELTA..delta is a phase angle which is controlled by the output of the control command section.

When the control is performed using the above equation (2), the control command of the reactive power may be controlled by the voltage E, and the control command of the active power P may be controlled by the phase angle Δδ.

For this reason, in the above configuration, the opening angle of the governor valve 12 is controlled by controlling the phase angle (Δδ) of the secondary windings 6a to 6c so that the rotational speed N and the electric power P are adjusted to the target values and the optimum efficiency is obtained. Needs to be controlled. Therefore, the active power P is used as information for controlling the phase angle. That is, the phase angle Δδ is set as follows: Δδ = ∫k ₁ (P−P ₀ ) dt + k _1P (P−P ₀ ) (3) Here, P ₀ is a target value of active power, P is an actual value of active power, and k ₁ and k _1P are constants. Thus the phase angle .DELTA..delta ₁ value calculated in is output to the amount of excitation setter 17.

The excitation amount setting unit 17 obtains the excitation voltages v _a , v _b , v _b of the secondary windings 6a to 6c based on the rotation speed N (frequency f) and the phase angle Δδ, and a calculation formula thereof ( Equation (2) is as shown in equation (2). The calculated excitation voltages v _a , v _b , v _b are used as phase shifters 23.
a, 23b, and 23c, and is provided to each of the windings 6a to 6c. Note that 1
Reference numeral 8 denotes a feedback adjustment unit for correcting the excitation voltage.

As described above, while controlling so as to obtain the optimum valve opening under the head command H, the phase angle Δδ value of the secondary windings 6a to 6c is calculated from the difference between the power control command value P ₀ and the actual output. Then, the power is controlled to be an appropriate power value.

According to the practical example described above, both the function of controlling the governor valve opening degree from the head and the actual input value and the function of controlling the phase angle of the secondary excitation voltage by the difference between the target value and the actual value of the electric power are both used. Since the AFC operation during pumping can be stably controlled to the target value, the effect on stability is extremely large.

Furthermore, in a pumped storage power generation system that generates electricity during the daytime and pumps up during the night to cover the fluctuating load of the system, it can operate efficiently even at the time of pumping operation and the power determined by the system, resulting in extremely high economic efficiency. .

〔The invention's effect〕

As described above, according to the present invention, in the variable speed power generation system, when performing the AFC operation, it is possible to stably control the target power value while maintaining high efficiency.

[Brief description of the drawings]

1 is a system diagram showing an outline of an embodiment of the present invention, FIG. 2 is a block diagram showing a specific example thereof, FIG. 3 is a characteristic diagram showing a change in efficiency with respect to output, and FIG. 4 is a governor with respect to input. FIG. 5 is a characteristic diagram showing a change in valve opening, and FIG. 5 is a block diagram showing the principle of a general variable speed power generation system. Ex _: Excitation circuit, G _1: Variable speed machine, C: Control command unit, T: Operating terminal, 1 ... Stator, 2 ... Rotor, 3 ... Slip frequency detection unit, 4 ... ... Frequency / voltage converter, 5a-5c ... Phase winding of stator a, b, c, 6a-6c ... Phase winding of rotor a, b, c, 7 ... Rotation speed measuring part, 10 … Power system, 11… rotation speed detector, 13… water turbine, 14… servo system, 15… delay circuit, 16… secondary winding phase angle calculator, 17… secondary winding excitation Amount setting unit, 18: Voltage adjustment unit, 19: Current transformer, 20: Voltage transformer, 21: Active power calculation unit, P _0: Power control command value, N: Speed, 23a, 23b , 23c …… Phase shift section, 25 …… Optimal valve opening calculation section.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Eiji Haraguchi 3-3-22 Nakanoshima, Kita-ku, Osaka City, Osaka Prefecture Inside of Kansai Electric Power Company (72) Inventor Shigeaki Hayashi 3-3-1 Nakanoshima, Kita-ku, Osaka City, Osaka 22 Kansai Electric Power Co., Inc. (56) References JP-A-62-236393 (JP, A)

Claims (1)

(57) [Claims] An operation control method for a variable-speed pumped-storage power generation system that operates a coiled induction machine connected to a water turbine in response to a change in system load, wherein an actual input power value of the induction machine is detected during pumping operation. In addition, while controlling the phase angle of the exciting current of the induction machine to reduce the deviation between the actual input power value and the given power control command, the input power value set in advance using the lift of the water turbine as a parameter And a governor valve opening corresponding to the given head command and the actual input power value based on the correlation between the governor valve opening and the governor valve opening, and operating the governor valve of the water turbine to the determined governor valve opening. And an operation control method for the variable speed pumped storage power generation system, wherein a change in the power control command is delayed.