JP2539519B2 - Control device for variable speed pumped storage generator motor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a control device for a variable speed pumped-storage generator motor, which AC excites a secondary winding of a generator motor using a frequency converter, and in particular, the load is cut off. The present invention also relates to a control device for a variable speed pumped storage generator / motor that can prevent an increase in output voltage.

[Conventional technology]

Conventionally, a synchronous machine is generally used as a generator motor of a pumped storage power generation system. In that case, since only the operation at a constant rotation speed can be performed, there are problems that the efficiency of the pump turbine decreases due to the amount of power generation, the amount of pumped water, and the head, and that the load cannot be adjusted during the pumping operation.

Therefore, a variable speed pumped-storage power generation system has been proposed which solves the above-mentioned problems by making the rotation speed of the 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.

The main difference between such a variable speed machine and the above-mentioned synchronous machine is that, in the case of a synchronous machine, the torque commensurate with the load torque (active power) is generated by changing the internal phase difference angle. While the current does not contribute to the torque, in the case of a variable speed machine, the secondary excitation current is a torque component (also called active power combination or q-axis component) and a magnetic flux direction component (reactive power component, Since it can be decomposed into a voltage component and a d-axis component) and controlled, the active power and the reactive power can be controlled independently (see, for example, Japanese Patent Laid-Open No. 62-181698).

[Problems to be Solved by the Invention]

However, the above-described variable speed machine may cause the following problems due to its features.

That is, when the near end or far end of the power system is cut off or when the load of the variable speed machine is cut off (hereinafter, generally referred to as “when the power system is cut off”),
That is, a phenomenon in which the output voltage rises sharply appears. In the case of a synchronous machine, the internal phase difference angle is returned to zero when the system load is removed, the DC excitation current is throttled with respect to the increase ΔV in output power, and the output voltage is controlled to be held at the command value.
However, in the variable speed machine, when the system load is removed, the torque current component also contributes to the magnetic flux direction component for voltage control, so that the increase ΔV in the output voltage increases. That is, the direction of the magnetic flux shifts to the direction of the exciting current obtained by vector-synthesizing the magnetic flux direction current component Id and the torque current component Iq before the interruption. The amplitude of the synthesized excitation current is
Since it is larger than the amplitude of Id, ΔV increases.

When the system load is removed, active power control operates in the direction of increasing Iq, and reactive power control (voltage control) operates in the direction of decreasing Id. Therefore, those currents Iq, I
d reaches the upper limit value and the lower limit value, which are set in control respectively,
The output voltage cannot be controlled.

In the case described above, stopping the secondary excitation can solve problems such as an increase in output voltage.
Excitation cannot be stopped because the operation of the power system requires high-speed or rapid recovery of the interruption.

An object of the present invention is to solve the above-mentioned problems in the prior art. That is, it is an object of the present invention to provide a method and apparatus for exciting a variable speed pumped storage generator motor that can suppress a problem caused by an increase in output voltage when the power system is cut off.

[Means for solving the problem]

The present invention relates to a generator motor in which a primary winding is connected to a power system via a circuit breaker, a frequency converter for AC-exciting a secondary winding of the generator motor, an active power command value and output detection of the generator motor. A torque current component calculating means for calculating a torque current component for making the deviation from the active power value zero, and a magnetic flux for calculating a magnetic flux direction current component for making the deviation between the output voltage command value of the generator motor and the output detection voltage value zero. A power control device having a directional current component calculation means, wherein the torque current component calculation means and the magnetic flux direction current component calculation means are torque current components,
Control of variable speed pumped-storage generator motor characterized in that the current components in the magnetic flux direction are controlled independently of each other, and the frequency converter outputs AC excitation in accordance with the result of vector composition calculation of the torque current component and the magnetic flux direction current component. In the device, a load cutoff detector that detects that the load has been cut off depending on the open / close state of the circuit breaker, and a torque current component is set so that the torque current component becomes zero by a load cutoff signal from the load cutoff detector. A torque current component switching means for switching to a set value, and a magnetic flux for switching the magnetic flux direction current component to a second set value so that a rated voltage value is generated in the magnetic flux direction current component in response to a load cutoff signal from a load cutoff detector. The directional current component switching means is provided, and the frequency converter outputs the AC excitation by the torque current component switching means and the magnetic flux direction current component switching means. It is obtained so as to control.

[Action]

 Here, the operation of the present invention will be described.

First, when the power system is cut off, the variable speed pumped storage generator motor (hereinafter, simply referred to as the generator motor) is released from the power system, so that the output active power becomes zero, and the active power control means commands the active power. Torque current component to keep the value
The power control means acts to increase the Iq, and the power control means acts to decrease the magnetic flux direction current component Id in order to control the increase in the output voltage. Then, since the active power is not actually output, the increased torque current component Iq acts in the direction of increasing the output voltage, and the voltage control means loses its function and the output voltage is rapidly increased.

However, according to the present invention, when the power system is interrupted, the interruption is detected and the first set value is switched so that the torque current component becomes zero. Since the setting value is switched to the second set value for generating the rated voltage at some times, the AC excitation output resulting from the vector combination is narrowed down instantaneously. Therefore, the above-mentioned action of increasing the output voltage due to the torque current component is suppressed, and further, the current in the magnetic flux direction also becomes a no-load current, so that the output voltage is suppressed from becoming a transient unstable state thereafter. become.

〔Example〕

 Examples of the present invention will be described below.

FIG. 2 shows an overall configuration diagram of a variable speed pumped storage hydropower system that is an embodiment of the present invention, and FIG. 1 shows a calculation block diagram of an exciting current command of the exciter.

In FIG. 2, the primary terminal of the variable speed generator-motor 2 connected to the water turbine 1 is connected to the power system 5 via the circuit breakers 3 and 8 and the main transformer 4. The secondary winding of the generator motor 2 is a 4-wire type having a neutral point, and the three-phase AC exciting current is used as a cycloconverter 6 (6A to 6A) as a frequency converter.
C). Each of the cycloconverters 6A to 6C is connected to the primary side of the main transformer 4 via an exciting transformer 7 (7A to 7C) and a circuit breaker 8.

Active power P _L flowing out of the generator motor 2 and output voltage V _G
The detection value of is obtained by the transformer 9 for an instrument, the AC 10, and the power / voltage detector 11. Also the detector
Reference numeral 11 detects that the load is cut off from the power system by the breakers 8, 16A, 16B and outputs a load cutoff detection signal CBT.
The phase detector 12 detects the phase of the secondary induced electric power of the generator motor 2. The reference signal calculation circuit 13 forms a reference signal waveform for secondary excitation, has a slip frequency ω _S , has a constant amplitude, and has a secondary amplitude based on the phase of the secondary induced voltage input. Inductive power and in-phase and π, respectively
/ 2 form a signal with cosωst, sinωst with a phase difference,
It is designed to output to the exciting current control device 14 (14A to 14C).

The power controller 15 determines the torque current component Iq based on the command value P _O and the detection value P _L of the active power input from the outside, and the magnetic flux based on the command value V _O and the detection value V _G of the output voltage. The direction current Id is determined and output to the exciting current control device 14 for each phase. That is, the first
As computation block diagram of the excitation current command shown in FIG, and P _O
With respect to P _L, the deviation ΔP _L is obtained by the adder 171, and then, in the power adjustment calculator 18 as the active power control means, the torque current component Iq is obtained so as to make ΔP _L zero, and this Iq is switched. Excitation current controller 14 via switch 251
It is adapted to be output to the current pattern calculator 22 (FIG. 2).

Similarly, for V _O and V _{G, the} deviation ΔV _G is obtained by the adder 172, and then in the voltage adjustment calculator 19 as the output voltage control means, the magnetic flux direction current Id is obtained in order to make ΔV _G zero,
Exciting current controller 14 (second switch)
It is output to the current pattern calculator 22 of FIG.

The switching switch 251 of the torque current Iq switches from the active power adjustment calculator 18 to the set value 26 in response to the load cutoff detection signal CBT from the detector 11. On the other hand, the switching switch 252 for the magnetic flux direction current Id has the voltage adjustment calculator 19 and the set value 27 for the time set in advance by the timer 21 for the flip-flop 20 for holding the state and the self-holding time setting timer 21 for the load cutoff detection signal CBT. Are switched. Therefore, after detecting the load shedding, the voltage control is temporarily stopped to set Id to the set value, but thereafter, the voltage control is restored.

The excitation current controller 14 is formed to include a current pattern calculator 22, a current control calculator 23, and an automatic pulse phase shifter 24. As shown in FIG. 1, the current pattern calculator 22 is a multiplier 281 that multiplies the input torque current component Iq by the fundamental wave signal cosωst, and the magnetic flux direction current component Id is also the fundamental wave signal s.
A vector composition operator that combines the output of the multiplier 282 that multiplies inωst with the respective vector and outputs the excitation current command value I ₂ .
It is formed including 29. Here, the arithmetic processing shown in the following equation (1) is performed.

I ₂ = Iq cos ωst + Id sin ωst = I ₂ cos (ωst +) (1) In addition, when the equation (1) is displayed as a vector, the following equation (2) is obtained. ₂ = d + q (2) The current control calculator 23 obtains the control phase angle Ec of the cycloconverter 6 so that the deviation between the detected value of the exciting current detected by the current transformer 29 and the command value I ₂ becomes zero. Automatic pulse phaser
Reference numeral 24 outputs an ignition pulse to the thyristor of the cycloconverter 6 based on the control phase angle Ec input and the power supply voltage signal input from the transformer 30.

The operation of the embodiment thus constructed will be described below with reference to FIGS. 3 and 4. The same subscripts in FIGS. 3 and 4 represent the same quantity,
Further, in the time chart shown in FIG. 3, description will be made assuming that the power system is interrupted at t1.

First, assume that the normal state. That is, the circuit breakers 3 and 8 shown in FIG.
When the 16B is turned on, the generator motor 2 supplies power to the grid. Active power P _L and output voltage _{G at} this time
Is controlled based on the torque current component Iq ₁ and the magnetic flux direction current component Id ₁ obtained by the power regulator 18 and the voltage regulator 19 in FIG. In this state, the levels of the exciting current I ₂₁ and the output voltage V _G are stable as shown in FIG. Further, the vectors of Iq ₁ , Id ₁ , and I ₂₁ are as shown in FIG. 4, and since the phases of the magnetic flux direction Φ ₁ and the current Id ₁ are the same, the responsiveness of the output voltage control and the active power control is good.

Then, when the cut-off in the electric power system 5 occurs at time t _1, the detection value P _L of the effective power becomes zero instantly, in the interior of the relationship of the generator motor 3, a magnetic flux direction of FIG. 4 in an instant Turning to Φ ₂ from Φ _1. Thus since the exciting current I ₂₁ is a factor of the voltage generator, the output voltage V _G as shown in FIG. 3
Rises sharply. On the other hand, the power regulator 18 and the voltage regulator 19
, T ₂ after the control delay time of those control systems
At this time, the detected value P _L that is the feedback value of active power control becomes zero, so the operation starts in the direction to increase the torque current component Iq, and the magnetic flux direction current component Id decreases due to the increase in the output voltage V _G. The operation is started in the direction of.

If load shedding is detected at time t ₃ , the command value Id of the magnetic flux direction current is set to Id ₃ with the flip-flop 20 set, and Iq becomes a set value (Iq ₃ = 0). As a result, the exciting current is instantly reduced to I ₂₃ , and the output voltage V _G begins to fall. After that, from time t ₄ , the voltage regulator
With the function of 19, the magnetic flux direction current component Id is controlled so that the output voltage V _G is held at the command value V _O , and stable operation can be continued.

By the way, according to the conventional method, since the switching by the load cutoff detection in FIG. 1 is not provided, as shown by the dotted line in FIG. 3, the torque current component Iq and the magnetic flux direction current component Id are respectively The upper and lower limits indicated by Iq ₄ and Id ₄ in the figure are reached. As a result, the exciting current I ₂ becomes I ₂₄ ,
The high output voltage V _G will continue to be generated. The vector relationship at this time is as shown in FIG.

The present invention is not limited to the above embodiment,
The point is to control the rise of the output voltage by detecting the interruption of the power system and suppressing the torque secondary excitation current I ₂ so as to reduce it.

For example, FIG. 5 shows an embodiment in which the arithmetic block of FIG. 1 is assigned to a control device. In FIG. 5, the excitation current control device 14 is provided with switches 251 and 2 for switching the magnetic flux direction current command Id to the set value 27 and the torque current component Iq to the set value 26, respectively.
52 is provided, and the load cutoff detection signal CBT is input to switch the Iq to the set value when the load cutoff is detected. Although the switching switches 251, 252 and the like can be provided in the power control device 15, the configuration of FIG. 5 allows the power control device 15 to perform the excitation control as compared with the case of being installed in the power control device 15. Since the dead time such as data transmission to the device 14 can be shortened, it is effective in suppressing the voltage rise.

〔The invention's effect〕

As described above, according to the present invention, the rise of the output voltage is suppressed by rapidly controlling the torque current component and the magnetic flux direction component independently using the circuit breaker switching information of the power system, and the torque is increased. Since the current component and the magnetic flux current component are controlled to the setting values that match each other when the load is cut off, the fluctuation of the output voltage is reduced to the stable state at no load while minimizing the transient voltage fluctuation. Will be able to move to.

[Brief description of drawings]

FIG. 1 is a block diagram of an essential part of an embodiment of the present invention, and FIG.
FIG. 3 is an overall configuration diagram of a variable speed pumped storage power generation system according to an embodiment of the present invention, FIG. 3 is a time chart for explaining the operation of the embodiment shown in FIG. 2, and FIG. 4 is shown in FIG. FIG. 5 is a vector diagram of signals of respective parts for explaining the operation of the embodiment shown, and FIG. 5 is a diagram showing another embodiment of the present invention. 1 ... Pump turbine, 2 ... Variable speed generator motor, 3,8,16 ...
… Breaker, 4,7 Transformer, 5 …… Power system, 6 …… Frequency converter (cyclo converter), 12,13 …… Phase detection, 15 …… Power control device, 14 …… Current control device , 18,19
...... Control calculator, 20 …… Flip-flop, 21 …… Timer, 22 …… Vector calculator, 35 …… Change rate limiter, 36 …… AND circuit, 38 …… Function generator, 251,252,25
3,254,255 ... Switching switch, CBT ... Load cutoff detection signal, Id ... Flux direction current command, Iq ... Torque direction current command, Ec ... Control angle, P _L ...... Active power, P _O・ ・ ・ Power command value , V _G ... voltage, V _O ... voltage command.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshihiko Harashima 5-2-1 Omika-cho, Hitachi-shi, Ibaraki Hitachi Omika factory (72) Inventor Hiroshi Sugisaka 5-2-1 Omika-cho, Hitachi-shi, Ibaraki No. 1 Hitachi Ltd. Omika Plant (72) Inventor Masao Oura 3-22 Nakanoshima, Kita-ku, Osaka City, Osaka Prefecture 3-22 Kansai Electric Power Co., Inc. (72) Hiroto Nakagawa 3 Nakanoshima, Kita-ku, Osaka City, Osaka Prefecture Chome 3-22 Kansai Electric Power Co., Inc. (72) Inventor Satoshi Kuzusaka 3-3-22 Nakanoshima Nakanoshima, Kita-ku, Osaka City, Osaka Prefecture (56) Reference Kansai Electric Power Co., Ltd. (JP) 3-60400 (JP, A) JP-A-1-243895 (JP, A)

Claims (2)

(57) [Claims] 1. A generator motor having a primary winding connected to a power system via a circuit breaker, a frequency converter for AC-exciting a secondary winding of the generator motor, and an active power command value for the generator motor. A torque current component calculating means for calculating a torque current component that makes the deviation from the output detection active power value zero, and a magnetic flux direction current component that makes the deviation between the output voltage command value of the generator motor and the output detection voltage value zero. A power control device having a magnetic flux direction current component calculating means for calculating, wherein the torque current component calculating means and the magnetic flux direction current component calculating means control the torque current component and the magnetic flux direction current component independently of each other, In the control device of the variable speed pumped storage generator-motor, wherein the frequency converter outputs an alternating-current excitation according to a result of vector composition calculation of the torque current component and the magnetic flux direction current component. And a load cutoff detector for detecting that the load has been cut off depending on the open / closed state of the circuit breaker, and a torque cutoff signal from the load cutoff signal from the load cutoff detector so that the torque current component becomes zero. The torque current component switching means for switching to the set value of 1 and the magnetic flux direction current component so as to generate the rated voltage value when the load magnetic flux direction current component is no load by the load cutoff signal from the load cutoff detector. And a magnetic flux direction current component switching means for switching to a set value, wherein the frequency converter controls the AC excitation output by the torque current component switching means and the magnetic flux direction current component switching means. Control device. 2. The control device for a variable speed pumped storage generator motor according to claim 1, wherein the magnetic flux direction current component switching means switches to the second set value for a predetermined period and then outputs the output voltage. A control device for a variable speed pumped storage generator motor, wherein a deviation between a command value and the output detection voltage value is set to zero.