JPH08254175A - Variable speed pumping-up device - Google Patents

Abstract

PURPOSE: To provide a variable speed pumping-up system capable of regulating an electric motor load even during pumping up operation and coping with control of a power system such as AFC. CONSTITUTION: A variable speed pumping-up device comprises an optimum rotation speed function generator 12 to input a power command P0 and a total head HST from the outside and compute a current optimum rotation speed NOPT a power control correction signal generator 16 to compare an output signal NOPT therefrom and an actual rotation speed N with each other and form a negative feedback circuit, and have at least an integrating element to reduce a deviation therebetween to zero and work to output a correction signal Q and a negative feedback circuit to add the power command P and the correction signal 5 to generate a synthetic signal P0 +ε, and compare it with an actual input PM. Further, the variable speed pumping-up device comprises a power controller 7 having at least an integrating element to reduce the deviation therebetween to zero; and a power converter 3 to perform AC excitation control so that the input P of the electric motor 2 forms the synthetic signal P0 +ε.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable speed pumping system connected to a power system consisting of a rotary electric machine capable of operating at any desired rotational speed and a power conversion device. In particular, the present invention relates to a variable speed pumped storage power generator that operates with high efficiency by adjusting the input of a pump driving electric motor according to a load setting command given from the outside. In a conventional pumped-storage power generation system using a synchronous generator-motor, the rotational speed of a pump turbine is fixed to the same constant value in both power generation operation and pumping operation. FIG. 7 is a diagram showing the performance of a pump having movable guide vanes, which is an example of operating characteristics of such a pumped-storage power generation system during pumping operation. In the figure, 1 and 1 ′ are guide vane opening degrees. To Y ₁ ,
It is a relationship curve between the pumped water quantity Q and efficiency η when fixed to Y ₂ and the pump rotation speed is kept at N ₂ , and 2, 2 ′ is a relationship curve between the pumped water quantity Q and the total head H corresponding to the above. . As is apparent from FIG. 7, the rotation speed N
Also, if the guide blade opening Y is fixed, the maximum efficiency point (points a and b in the figure) at each guide blade opening will be exceeded, and a sharp drop in efficiency will occur, causing vibrations and cavitation. Since the operating characteristics deteriorate, in the prior art, as shown by the envelope connecting the points a and b (indicated by a broken line), the guide vane opening is uniquely adjusted according to the lift H to operate. During the pumping operation of such a pumped storage power generation system, the load becomes a simple load with no freedom (no adjustment is effective) from the viewpoint of the power system, and no adjustment is made to improve the power supply and demand balance of the power system. could not. In view of such background of the prior art, studies and proposals are being made to make the rotational speed of the pump turbine variable so as to increase the degree of freedom during pump operation. No. 533 “Variable speed operation characteristics of large-capacity synchronous motor” is also an example thereof, but the variable speed pumping system is not specifically mentioned. On the other hand, as a conventional variable speed conduction system, a method of providing a frequency converter between an AC system and an electric motor, a primary side of a wire wound induction machine is connected to an AC system, and a secondary side and an AC system are connected. There is a method to install a frequency converter between them,
Each of them controls a frequency converter to give an arbitrary rotation speed to the electric motor. Of the methods using these frequency converters, an example of a method for realizing a variable speed pumping operation by providing a frequency converter between an AC system and an electric motor is disclosed in, for example, Japanese Patent Laid-Open No. 48-21045. There is a disclosure in the gazette.
However, in this known example, no specific control circuit diagram was mentioned. An object of the present invention is to clarify a concrete control circuit and a device configuration which have not been clarified in the above-mentioned prior art, to make it possible to adjust the electric motor load even during the pumping operation, and It is to provide a variable speed pumping system capable of controlling the electric power system. The present application is directed to a variable speed pumping system including a variable speed drive device connected to a power system composed of a rotary electric machine and a power conversion device, and a pump driven by the variable speed drive device. In this system, an electric power detection means for detecting an actual electric power value input to the electric motor and a rotational speed detection means for detecting an actual rotational speed of the electric motor are provided, and an electric power command value given from the outside and the electric power detection. The power converter is controlled so that the deviation from the actual power value given by the means is minimized, and the optimum rotation speed command of the pump is generated in accordance with both the power command value and the lift of the pump. A function generator is provided to minimize the deviation between the optimum rotation speed command value given by the function generator and the actual rotation speed value given by the rotation speed detecting means. The power converter is controlled so that As a result, during pumping operation, operation control in which the pump head is also taken into consideration is given, and the object of highly efficient load adjustment operation of the pump in accordance with a power command from the outside is achieved. BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below with reference to the embodiments shown in the drawings. FIG. 1 is a control circuit diagram according to an embodiment of the present invention. The details of the AC excitation circuit for power control are not directly related to the present invention.
Not shown. This embodiment is roughly classified as shown in the figure.
It has a rotation speed control circuit system, a power control circuit system, and a guide vane control circuit system. First, the rotation speed control circuit system receives as input the power command P ₀ from the outside and the total head H _ST at that time,
The optimum rotation speed function generator 12 for calculating the optimum rotation speed N _OPT at that time is compared with the output signal N _OPT from the optimum rotation speed function generator 12 and the actual rotation speed N, and a negative feedback circuit is constructed to make the deviation between them zero. Therefore, the power control correction signal generator 16 is provided with at least an integration element and functions to output the correction signal ε. Further, the power control circuit system has a power command P
₀ and the correction signal ε are added to form a combined signal P ₀ + ε,
Comparing with the actual input P _M and constructing a negative feedback circuit,
A power controller 7 having at least an integral element for making the deviation zero, and thereby an input P of the electric motor 2 (10).
_The power converter 3 (17) performs AC excitation control so that _M becomes the combined signal P ₀ + ε. Further, the guide vane control circuit system receives the load command P ₀ and the total lift H _ST from the outside as inputs, and calculates the optimum guide vane opening Y _OPT at that time. And the output signal Y _OPT and the actual guide vane opening Y are compared with each other, a negative feedback circuit is constructed, and an integral element included in the negative feedback circuit constitutes a guide vane controller 9 for making these deviations zero. Has been done. Here, the total head H _ST represents a simple water level difference between the upper and lower water storage tanks of the pumping system, while the actual head H is the total head H _ST of the water channels of the pumping system. It is defined as the sum of losses. According to this embodiment, the actual rotational speed N = optimal rotational speed N _OPT is obtained by the rotational speed control circuit system, and the actual input P _M = P ₀ + ε by the power control circuit system, and
The guide vane control circuit system can obtain the actual guide vane opening Y = the optimum guide vane opening Y _OPT . Here, the input P _P required by the pump 4 and the input P _M to the actual electric motor are the complete moments GD ² and N of the electric motor and the pump which can be regarded as a kind of integral element, the rotation speed control circuit, and the power control circuit. Since the deviation becomes zero due to the negative feedback circuit consisting of P _M = P _P , and if the error of the function generator 12 is ignored, Y _OPT = P ₀ , so P ₀ = Y _OPT = Y = P _P = P _M
The power control correction signal ε becomes zero. Therefore, according to this embodiment, the object of the present application that the actual input P _M is controlled according to the power command P ₀ from the outside can be achieved. FIG. 2 shows an embodiment of the present invention in which the wound-rotor induction machine 2 is used as a variable speed electric motor according to the control circuit of FIG. 1 described above. The primary side of the wire wound induction machine 2 is connected to the power system 1, and the secondary side is connected to the power converter 3, whereby the induction machine 2 is connected.
The input of is to be increased or decreased by the power converter 3 according to the phase command of the alternating excitation current. The actual input P _M is detected by the power detector 6, and the actual rotation speed N is detected by the rotation speed detector 5 and is input to each comparator. As is apparent from FIG. 2, the power command P ₀ from the outside and the total head H _{ST at} that time are input to the optimum rotational speed function generator 12 in this case as well. , By this, the optimum rotation speed N _{OPT at} that time
Is calculated. FIG. 3 shows another embodiment of the control circuit of FIG. 1, in which a synchronous machine 10 is used as a variable speed electric motor and a power system 1 is used.
It is a configuration example in the case where a power converter 17 is provided between the and the synchronous machine 10. A phase detector 11 is provided for matching with the phase command to the power converter. FIG. 4 shows an example of the optimum guide vane opening function generator, and FIG. 5 shows an example of the optimum rotation speed function generator. The signal values are calculated according to the load command P ₀ and the actual lift H, respectively. To be done. Note that points a to f and points a'to f'in the figure correspond to points in the pump characteristic diagram shown in FIG. This FIG. 6 is created based on the pump characteristic diagram of FIG. 7, and the curve in the figure shows the envelope characteristic shown by the broken line in the total head H curve for the pumping amount Q of FIG. 7 for each rotation speed. The curve shows the required load P _P with respect to the pumping amount Q from the characteristics of the curve. As a result, the optimum operating point corresponding to the operating condition at that time is given to the above-mentioned two kinds of function generators while maintaining the envelope operation restricted by the peculiar characteristic of the pump, and the actual rotation. It can be seen that the relationship between the speed N and the guide vane opening Y needs to be controlled by the function generator outputs N _OPT and Y _OPT , respectively. The horizontal axes in FIGS. 4 and 5 are set to the total head H (vertical axis in FIG. 6) for simplification of description, but the actual head H _ST is used as a signal in the embodiment. In that case,
As indicated by the alternate long and short dash line, the optimum point may be defined by a curve that is a line of the actual head obtained by subtracting the channel loss that is a function of the pumping quantity Q from the total head, and is shown by the point f. The curve indicated by the alternate long and short dash line in FIG. 7 shows the rotation speed from N ₂ to N ₃ when the guide vane opening is fixed to Y _2.
The characteristic curve when changing to is shown, showing how the operating point corresponding to point a, which is the optimum efficiency point, moves to point c. A curve in FIG. 6 is obtained by moving the operating points on the whole envelope in this manner for each rotational speed. FIG. 8 shows a modification of the embodiment shown in FIG. As described above, the optimum rotation speed N _OPT and the optimum guide vane opening Y _OPT according to the power command P ₀ from the outside are determined to be one, so N
_From the relationship of _OPT = corresponding to P ₀ = N, the input of the optimum guide vane opening generator 8 is the actual rotation speed N. FIG. 9 shows another modification of FIG. In the embodiment of FIG. 2, the input to the optimum guide vane opening function generator 8 is the optimum rotation speed signal N _OPT . According to the present invention, it is possible to provide a variable speed pumping system capable of controlling the load according to an electric power command from the outside. Therefore, in order to cover the fluctuating load of the system, power generation in the daytime,
In a pumped storage power generation system that operates as pumped water at night,
Even during pumping operation, it can be efficiently handled by adjusting the electric power required by the grid, so the economic effect is extremely large.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a control circuit diagram according to an embodiment of the present invention. FIG. 2 is a configuration diagram showing an embodiment of the present invention when an induction machine is used. FIG. 3 is a configuration diagram showing an example of a variable speed pumping device in the case where a power converter is provided between systems using a synchronous machine. FIG. 4 is a characteristic diagram showing an example of an optimum guide vane opening function generator. FIG. 5 is a characteristic diagram showing an example of an optimum rotation speed function generator. FIG. 6 is a characteristic diagram of a variable speed pump. FIG. 7 is a characteristic diagram of a pump. FIG. 8 is a configuration diagram showing an embodiment in which the input of the optimum guide vane opening function generator is the actual rotation speed in the embodiment of FIG. FIG. 9 is a configuration diagram showing an embodiment when an optimum rotation speed signal N _OPT is input in FIG. [Explanation of Codes] 1 power system 2 winding type induction machine 3, 17 power converter 4 pump turbine 5 speed detector 6 power detector 7 power controller 8 optimum guide blade opening function generator 9 by speed input 9 guide blade control Device 10 Synchronous machine 11 Phase detector 12 Optimal rotation speed function generator 13 Optimal guide vane opening function generator 16 by P command input Power control correction signal generator

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Akira Bando             3-1-1 Sachimachi Hitachi City, Ibaraki Prefecture Stock Association             Hitachi, Ltd.Hitachi factory (72) Inventor Yasuteru Ohno             3-3-22 Nakanoshima, Kita-ku, Osaka City, Osaka Prefecture             Kansai Electric Power Co., Inc. (72) Inventor Shigeaki Hayashi             3-3-22 Nakanoshima, Kita-ku, Osaka City, Osaka Prefecture             Kansai Electric Power Co., Inc.

Claims (1)

[Claims] 1. In a variable speed pumping device including a motor connected to a power system, a power converter that excites a secondary winding of the motor with an alternating current, and a pump pump coupled to a rotation shaft of the motor, the variable speed pumping device is input to the motor. An electric power detecting means for detecting an actual electric power value and a rotational speed detecting means for detecting an actual rotational speed of the electric motor are provided, and a deviation between an electric power command value given from the outside and an actual electric power value given by the electric power detecting means is provided. While controlling the power converter so as to minimize, a function generator that generates an appropriate rotation speed command of the pump according to both the power command value and the lift of the pump is provided, and the function generator Is configured to control the power conversion device so that the deviation between the appropriate rotation speed command value given by the rotation speed detection means and the actual rotation speed value given by the rotation speed detection means is minimized. Variable speed pumped storage apparatus according to claim. 2. The variable speed pumping device according to claim 1, wherein the function generator generates a pumping pump proper rotation speed command corresponding to the power command value in a steady state.