JPH04193100A - Voltage controlling equipment for pumped storage generating system of variable speed type - Google Patents

Abstract

PURPOSE:To control a system voltage and a system phase stably, by controlling the output voltage of a frequency converter through a phase control signal, which converges, the deviation between the voltage signal sensed through a voltage sensing means and a voltage reference signal used as the reference of the sensed voltage signal, into zero, and by also changing, in that case, the control gain of the aforesaid voltage control system, according to the magnitude of the sensed voltage signal. CONSTITUTION:A comparator 6 compares a voltage signal inputted from a voltage sensor 4 with a voltage reference signal used as the reference of a primary voltage, the voltage reference signal being inputted from a first voltage reference generator 5. Then, the deviation ev between the sensed voltage signal and the voltage reference signal is inputted to a voltage controller 9. A gain regulator 7 changes the control gain of the voltage controller 9, according to the deviation between a second voltage reference signal and the voltage signal sensed by a voltage sensor 4. The voltage controller 9 inputs a gain obtained from the gain regulator 7 and the voltage deviation (ev) obtained from the comparator 6, and gives to a phase controller 10 a phase control signal obtained from the deviation multiplied by the control gain. The phase controller 10 controls the amplitude and phase of the output voltage of the frequency converter 3, according to the phase control signal.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention provides a variable speed pumped storage power generation system in which the secondary side of a wound synchronous generator motor is excited with variable frequency alternating current using a frequency converter. In particular, when performing a test power transmission operation, the control gain is changed according to the magnitude of the primary voltage of the wound synchronous generator-motor, and the output voltage of the frequency converter is controlled so that the gain of the entire voltage control system does not decrease. This invention relates to a voltage control device for a variable speed pumped storage power generation system.

(Conventional technology) Thermal power plants and hydroelectric power plants are attracting attention as power plants for frequency adjustment to control the grid frequency to a constant level because it is easy to control the amount of power generated according to changes in power demand. Bathing.

However, due to the recent increase in the number of nuclear power plants, thermal power plants that shut down at night when demand for electricity is low, and hydropower generation capacity, have tended to increase, resulting in a shortage of nighttime frequency adjustment capacity. Therefore, as a method to increase frequency adjustment capacity at night, the speed of pumped storage power plants that pump water using surplus electricity at night is made variable, and the rotational speed of the generator motor is controlled in response to changes in power demand to generate pumped storage power. A variable speed pumped storage power generation system that adjusts the

By the way, in pumped storage power plants, in the unlikely event that a wide-scale power outage occurs due to some unforeseen cause, a so-called test transmission operation is carried out to supply on-site power to a thermal or nuclear power plant that is to be activated to restore the system. There are things that are done. This trial power transmission operation involves operating the pumped storage power plant's generator motor in generation mode to charge the line to the thermal or nuclear power plant, then supplying power to the internal load of the thermal or nuclear power plant, and connecting the generator to the grid. This continues until it is paralleled to . In this case, the voltage at the transmission end of the pumped storage power plant needs to be maintained constant not only during line charging, but also during the process in which the plant's loads are sequentially turned on.

However, as the generator-motor in conventional pumped storage power plants uses a synchronous generator-motor (hereinafter referred to as conventional machine) that is only excited by direct current and can only be operated at a constant speed, the terminal voltage of the generator depends on the excitation current. It is determined by the voltage induced by the voltage and the load conditions connected to the grid. Therefore, when other power sources are connected to the grid, the phase of the grid voltage is stable, and in the case of test transmission operation, for example, when a load is applied to or removed from the grid, the transient phenomenon Since the magnitude and phase of the current change, there may be a problem in stabilizing the system.

(Problem to be solved by the invention) As described above, when a trial power transmission operation is performed using a conventional machine, the phase of the grid voltage changes transiently due to changes in the grid load, etc.
The problem is that the voltage fluctuation becomes large and the recovery characteristics deteriorate.

The present invention provides a variable speed pumped storage power generation system equipped with a wound-rotor synchronous generator-motor, by changing the control gain according to the primary voltage of the wound-rotor synchronous generator-motor to prevent the gain of the entire voltage control system from decreasing. An object of the present invention is to provide a voltage control device for a variable speed pumped storage power generation system that has good voltage control characteristics and can stably control system voltage and phase even when load fluctuations occur.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the present invention has a primary side connected to an AC system, and a secondary side connected to the AC system via a frequency converter. In a variable speed pumped storage power generation system consisting of a wound synchronous generator motor driven by a prime mover,
Voltage detecting means for detecting the primary voltage of the wound synchronous generator-motor and outputting a voltage signal; and changing the control gain of the voltage control system according to the magnitude of the voltage signal input from the voltage detecting means. A gain adjustment means compares the voltage signal detected by the voltage detection means with a reference signal of the primary voltage of the wound synchronous generator-motor, and determines that the deviation is determined by the deviation and the control gain input from the gain adjustment means. A voltage control means that outputs a convergent phase control signal, and a tn LSI ff;! that is inputted from this voltage control means. I
and a phase control means for controlling the output voltage of the frequency converter in response to a control signal so that the gain of the entire voltage control system does not decrease.

(Function) In the voltage control device of the variable speed pumped storage power generation system having such a configuration, a phase control signal is provided that converges the deviation between the voltage signal detected by the voltage detection means and the voltage reference signal that is the reference stop. By changing the control gain of the voltage control system that controls the output voltage of the frequency converter according to the magnitude of the voltage signal, the decrease in control characteristics due to changes in the conversion gain of the frequency converter can be compensated for, so it is good. In addition to being able to perform voltage control with excellent control characteristics, it is also possible to stabilize the system voltage and phase even if load fluctuations occur.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a circuit configuration diagram showing a first embodiment of a voltage control device for a variable speed pumped storage power generation system according to the present invention. In FIG. 1, reference numeral 1 denotes a wound-rotor synchronous generator-motor constituting a variable speed pumped storage power generation system, which is driven by a prime mover such as a water wheel (not shown). The primary winding of this wound-type synchronous generator-motor 1 is connected to a system 2 that can be approximated by distributed constants of inductance and capacitance, and the secondary winding of this wound-type synchronous generator-motor 1 is connected to a frequency converter connected to system 2. It is excited by 3. These constitute the main circuit and are shown as single connections.

On the other hand, 4 is a voltage detector connected to the primary side of the wound-rotor synchronous generator-motor 1 via an instrument transformer PT, and this voltage detector 4 detects the primary voltage of the wound-rotor synchronous generator-motor 1. ,
While inputting the voltage signal to the comparator 6, the gain adjuster 7
Enter. The comparator 6 compares the voltage signal inputted from the voltage detector 4 with the voltage base $ signal inputted from the first voltage reference generator 5 and serves as a reference for the primary voltage, and calculates the deviation ev.
is input to the voltage controller 9. The gain adjuster 7 changes the control gain of the voltage controller 9 according to the deviation between the second voltage reference signal and the voltage signal detected by the voltage detector 4. The voltage controller 9 manually calculates the deviation ev between the gain from the gain adjuster 7 and the voltage from the comparator 6, and provides a phase control signal obtained by multiplying this deviation by a control key to the phase controller 10. This phase controller 10 controls the amplitude and phase of the output voltage of the frequency converter 3 according to the phase control signal.

Next, we come to the action of the voltage control device configured as shown in the second section.

Now, the voltage detector 4 indicates that one of the winding synchronous generator motors 1 is
When the next voltage is detected and the voltage signal is input to the comparator 6, this comparator 6 compares it with the voltage reference signal input from the first voltage reference generator 5 and determines the deviation ev from the voltage control. The signal is input to the device 9.

Further, when the voltage signal detected by the voltage detector 4 is input to the gain adjuster 7, this gain adjuster 7 inputs the voltage signal and a second voltage reference signal manually generated from the second voltage reference generator 8. The control gain of the voltage controller 9 is changed according to the deviation from the voltage controller 9. In other words, if the voltage signal becomes lower than the second voltage reference signal, the conversion cane of the frequency converter (the ratio of the human input signal of the phase controller that operates the frequency converter to the output voltage of the frequency converter) becomes smaller. , increase the control gain,
In the opposite case, the control gain is lowered. In this case, the voltage reference values set by the first reference voltage generator 5 and the second voltage reference generator 8 are not necessarily the same.

When the control gain from the gain adjuster 7 and the voltage deviation from the comparator 6 are input to the voltage controller 9, the voltage controller 9 outputs a phase control signal obtained by multiplying the deviation by the control gain to the phase controller 10. give to

Here, if we consider a general proportional integrator as the voltage controller 9, its control gains include a proportional gain and an integral gain of 1. For voltage deviation ev and control gain,
The phase control signal y calculated from is y-(Kp+/5)xev. Here, S is a Laplace operator. In this,
1 is input from the gain adjuster 7.

These become larger as the voltage signal becomes larger, and become smaller as the voltage signal becomes smaller.

A phase controller 10 controls the amplitude and phase of the output voltage of the frequency converter 3 according to the phase control signal.

If the minor loop has a current control system that controls the output current of the frequency converter, the current of the frequency converter 3 is detected by a current detector (not shown), and the current signal and the voltage controller 9 are used to detect the current of the frequency converter 3. It is sufficient to provide a current controller (not shown) that controls the phase control signal using the phase control signal as a current reference, and to control the frequency converter 3 with the phase controller using the output signal as a reference.

Figures 2 and 3 show the voltage drop and voltage recovery when a load is applied to the grid, respectively, when the control gain is fixed and when the control gain is made variable according to the first embodiment of the present invention. This shows the results of the simulation.

Each figure shows the waveforms of the voltage reference signal and the effective value voltage signal.

In FIGS. 2 and 3, T1 is the point at which an inductive load is applied to the system, and the voltage is shown in units. In addition, the voltage before load application, the minimum voltage after load application, and the voltage 300m5ec after load application are each V1611. Vm,
n+■,. 11.

When the control cane is fixed, the T
When a load is applied at one point, the voltage before the load is applied is 70%.
%, and recovered to a voltage of about 8596 after 300 m5ec.

On the other hand, when the control cane is made variable as in the first embodiment, the load is applied at time 14 as shown in Fig. 3, and when the voltage drops, the gain is changed to raise the control cane. Since the voltage is adjusted, the voltage at the time of load application is reduced to 78% of the voltage before load application L, 300 mr, e
After c, the voltage has recovered to about 95%.

By changing the control gain in accordance with the magnitude of the primary voltage of the wound-rotor synchronous generator-motor 1 in this manner, it is possible to reduce the amount of transient change in the primary voltage.

FIG. 4 is a circuit diagram showing a second embodiment of the present invention, in which the same parts as in FIG. 1 are given the same symbols and their explanation will be omitted.

In the second embodiment, as shown in FIG. 4, the voltage deviation signal from the comparator 6 is input to the gain adjuster 7, and the control cane of the voltage controller 9 is varied according to the value of this deviation signal. It was designed to do so.

With such a configuration, the voltage reference generator 8 shown in FIG. 1 can be omitted, and in particular, in FIG. Similar control characteristics can be obtained.

FIG. 5 is a circuit configuration diagram showing a third embodiment of the present invention, in which the same parts as in FIG. 1 are given the same symbols and their explanation will be omitted.

In the third embodiment, the cane adjuster 7 as shown in FIG.
The voltage deviation signal from the comparator 6 is inputted manually, and the cane Kx that changes according to the deviation is determined. For example, KX is xev with Kx =1+. Here, ev is the voltage deviation and K.

is an arbitrary gain.

The voltage controller 9 includes a fixed control key and a PI controller 91 that calculates the voltage deviation, and a multiplier 92 that multiplies the key by 8. The phase of the frequency converter is controlled by a phase controller 10 based on the output of the multiplier 92.

With such a configuration, the proportional integral Kei 7.

Since K1 is fixed, for example, when the voltage of another power source becomes stable after being turned on to the system, K can be set to zero to return to operation using the normal control gain.

[Effects of the Invention] As described above, according to the present invention, in a variable speed pumped storage power generation system equipped with a wound synchronous generator/motor, the primary voltage of the wound synchronous generator/motor is detected, and the magnitude of this voltage is By changing the control gain accordingly, the output voltage of the frequency converter is controlled so that the gain of the entire voltage control system does not change. A voltage control device for a variable-speed pumped storage power generation system that compensates for the conversion gain of the frequency converter to not decrease even if the primary voltage of the linear synchronous generator-motor drops by one level, and that can perform voltage control with good control characteristics. Can be provided.

[Brief explanation of drawings]

FIG. 1 is a circuit configuration diagram showing a first embodiment of the voltage control device for a variable speed pumped storage power generation system according to the present invention, FIG. 2 is a voltage response waveform diagram at the time of load application when the control gain is fixed, and FIG. FIG. 3 is a voltage response waveform diagram when a load is turned on during voltage control according to the first embodiment, and FIGS. 4 and 5 are circuit configuration diagrams showing the second and third embodiments of the present invention, respectively. . 1... Winding synchronous generator motor, 2... System, 3...
- Frequency converter, 4... Voltage detector, 5... First voltage reference generator, 6... Comparator, 7... Gain adjuster,
8. Second voltage reference generator, 9... Voltage controller, 91
...PI controller, 92.-multiplier, 10.-phase controller. Applicant's agent Patent attorney Takehiko Suzue No. 1 z No. 4261!5 2: Procedural amendment 4.2.26 Month, Day, 1998

Claims (1)

[Claims] In a variable speed pumped storage power generation system comprising a wound synchronous generator-motor whose primary side is connected to an AC system, whose secondary side is connected to the AC system via a frequency converter, and which is driven by a prime mover. , a voltage detection means for detecting the primary voltage of the wound-rotor synchronous generator-motor and outputting a voltage signal; and a gain adjustment means for changing the control gain according to the magnitude of the voltage signal inputted from the voltage detection means. , the voltage signal detected by the voltage detection means is compared with a reference signal of the primary voltage of the wound-rotor synchronous generator-motor, and the deviation is converged by the deviation and the control gain input from the gain adjustment means. voltage control means for outputting a phase control signal; and phase control means for controlling the output voltage of the frequency converter in accordance with the phase control signal input from the voltage control means so that the gain of the entire voltage control system does not decrease. A voltage control device for a variable speed pumped storage power generation system.