JPS60204273A - Drive device of nuclear reactor containing nuclear reactor cooling material recirculating pump - Google Patents

Abstract

PURPOSE:To restart an internal pump by controlling a recirculating pump at the starting time so that the ration V/F of the output frequency F of a power source to the output voltage V becomes larger than the value at the normal time. CONSTITUTION:The 3-phase AC voltage of a bus 1 is supplied through a stationary variable voltage variable frequency power source (VVVF) to an internal pump 5. A frequency controller 8 controls the output frequency of the VVVF3 proportionally to a speed request signal P. A voltage controller 12 controls the output voltage of the VVVF3 proportionally to the signal P. When the pump 5 is started, the signal P is set to a low value due to a low frequency start, but a bias signal is superposed to the input signal of a voltage controller 12 only at the starting time. As a result, the V/F value of the output of the VVVF3 becomes larger than the prescribed value, and the pump 5 can generate a large starting torque.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a drive device for driving a reactor coolant recirculation pump built into a nuclear reactor in a nuclear power plant, and particularly to a drive device for driving a reactor coolant recirculation pump built into a nuclear reactor in a nuclear power plant. This paper relates to improvements to the drive device used.

[Technical background of the invention and its problems]

In boiling type nuclear power plants, reactor output is controlled by controlling the recirculation flow rate of reactor coolant.

Among them, in Plan 1 to use an internal pump, which is a reactor coolant recirculation pump built into the reactor, a static variable voltage variable frequency NWA is used as a drive device for variable speed control of the internal pump. Sometimes used. The variable speed control of the internal pump is called r'V/F.
= constant control. This is because the internal pump motor is an induction motor, so if the V/F is constant, the excitation current of the internal pump motor will be constant, and there will be no risk of an increase in the temperature of the iron core due to overexcitation. Note that ■ is the output voltage of the static variable voltage variable frequency power supply, and F is its output frequency. Furthermore, the method for starting the internal pump is so-called "low frequency starting." this is,
This utilizes the general characteristic of induction motors that a lower power supply frequency generates a larger starting torque, and furthermore rV
/F=constant control", the voltage is lowered and the starting current can be reduced, making it possible to economically design a static variable voltage variable frequency power supply.

By the way, generally multiple internal pumps are used in one plant, but during normal plant operation, for example, one
When the internal pump of a reactor stops due to a failure or the like and is restarted after repair is completed, a flow path is formed in which a portion of the reactor coolant does not pass through the reactor core but passes through the stopped internal pump.

Under such conditions, a reverse torque is generated in the stopped internal pump, so a large starting torque is required to restart the pump. Therefore, when restarting an internal pump that has stopped due to a failure, etc., it is generally done by reducing the speed of other internal pumps and reducing the reverse torque acting on the stopped internal pump to less than the starting torque. There is.

However, this type of method has the following problems. That is, there is a problem that the plant operation rate decreases due to a decrease in the output of the plant, and it is also unfavorable for the operation of the electric power system. In addition, even when the internal pump is restarted after it has been stopped, it is possible to use an internal pump that generates sufficient starting power at a predetermined V/F. Due to size and structural limitations due to the installation at the bottom of the pressure vessel, it is extremely difficult to realize this.

[Purpose of the invention]

The object of the present invention is to provide a reactor built-in type that can restart an internal pump that has stopped during normal operation of an atomic couplant without reducing the output of the atomic couplant, and that is extremely effective for driving an internal pump. An object of the present invention is to provide a driving device for a nuclear reactor coolant recirculation pump.

[Summary of the invention]

The gist of the present invention is to utilize the general characteristic of induction electric imaging that the larger V/Flii, the larger the generated torque. Here, by increasing the V/F value, temporary overexcitation occurs, but since the time is short, there is almost no problem.

Therefore, under conditions where the internal pump is restarted after being stopped, a large starting torque can be generated only during startup by controlling the V/F value, and the internal pump can be restarted.

That is, the present invention provides a stationary variable voltage variable frequency RAM circuit that applies an output of a predetermined frequency and voltage to a reactor built-in reactor coolant recirculation pump in a nuclear power plant, and an output of this power supply circuit that applies a speed request signal. and a voltage control circuit that controls the output of the power supply circuit to have a voltage V proportional to the speed request signal, and drives the recirculation pump. In a drive device for a nuclear reactor coolant recirculation pump built into a nuclear reactor, the output of the power supply circuit is controlled such that the ratio V/F of F and V is larger than a steady state value only when the recirculation pump is started. The system is equipped with a starting circuit that controls the speed.

〔Effect of the invention〕

According to the present invention, when, for example, one of a plurality of internal pumps stops during normal operation of an atomic coupler, the internal pump can be restarted without reducing the plant output after its repair is completed.

becomes possible. Therefore, it is possible to improve the operating rate of the plant. Further, since there is no need to use a large internal pump that generates a sufficiently large torque at a predetermined V/F value, there are advantages such as ease of realization of reactor plans 1 to 1.

(Embodiment of the Invention) Fig. 1 is a circuit configuration diagram schematically showing a drive device according to an embodiment of the present invention.In the figure, 1 is a bus bar, and this bus bar 1 is Type variable voltage variable frequency power supply (
(hereinafter abbreviated as VVVF) 3. The output of the VVVF 3 is supplied to an internal pump 5 via an output transformer 4.

On the other hand, the speed request signal P from the system is supplied to the frequency control circuit 8 via the electric line 6.7.

Frequency 11ilJt [1 circuit 8 is connected to the above V via electric path 9
It is connected to the VVF3 and controls the output frequency of the VVVF3 in proportion to the input speed request signal P.

Further, the speed request signal P is supplied to the voltage control circuit 12 via the electric line 6.10.11.

The voltage control circuit 12 is connected to the VVVF3 through an electric line 13, and controls VV in proportion to the input speed request signal P.
It controls the output voltage of VF3. Here, the output of the output transformer 4, that is, the input voltage of the internal pump 5, is fed back to the electric line 11 via the instrument voltage transformer 14 and the electric line 15. As a result, the positive speed request signal P transmitted via the electric line 6.10 and the negative signal of the input voltage of the internal pump 5 transmitted via the electric line 15 are added.

Furthermore, the voltage of the DC power supply 16 is changed to the switch 17 and the electric line 1
8 to the electric line 11. When the switch 17 is ONL, the sum of the voltage calculated by hl and the voltage of the power supply 16 becomes the output setting voltage signal of the VVVF 3, which is supplied to the voltage control circuit 12 via the electric line 11.

Next, the operation of this apparatus configured as described above will be explained.

First, the three-phase AC voltage of the mother m1 is converted into a DC voltage by the rectifier (not shown) of the VVVF3, and then the VVVF
The voltage is again converted into a three-phase AC voltage by a No. 3 inverter (not shown). Here, the variable control method of the internal pump 5 is so-called rV/F=constant control. VVVF3
The output frequency of is controlled by the frequency control circuit 8 so as to be proportional to the speed request signal from the grid. Also, ■v
The output voltage of VF3 is controlled by the voltage control circuit 12 so as to be proportional to the speed request signal from the normal system.
Feedback of the input voltage of the internal pump 5 compensates for the effect on the output voltage due to voltage fluctuations.

Here, when starting the internal pump 5, the speed request signal P is set to a low value in order to start at a low frequency. The activation signal corresponding to the voltage of m16) is superimposed. As a result, the output voltage of VVVF3 becomes larger, and the V/F value of the output of vVvF3 becomes larger than a predetermined value.

Therefore, since the internal pump 5 can generate a large starting torque, the plant output can be reduced even under conditions where reverse torque is generated when, for example, one of the multiple internal pumps 5 stops. It is possible to restart the stopped internal pump 5 without reducing the internal pump 5.

As described above, according to this embodiment, after the internal pump 5 that has stopped due to a failure or the like is repaired, the switch 1
By turning on 7, it is possible to easily restart the plant without causing a decrease in the output of the plant. For this reason, it is extremely effective in improving plant availability. Further, since a conventional internal pump 5 can be used as is, it has the advantage of being extremely easy to implement.

FIG. 2 is a circuit diagram schematically showing another embodiment. Note that the same parts as in FIG. 1 are given the same reference numerals, and detailed explanation thereof will be omitted. This embodiment differs from the previously described embodiments in the means for supplying the activation signal. That is, the speed request signal P is transmitted to the electric line 10. switch 20 and electric circuit 21
It is supplied to the electric line 11 via. Also, start l
The I8 voltage setting signal Q is supplied to the electric line 21 via the switch 22 and the electric line 23. And the above switch 2
0 is 0FFL when ON1 is activated when the internal pump 5 is in steady state, and the switch 22 is OFF when the internal pump 5 is normally operated and turned ON when activated.

With such a configuration, if the startup@voltage setting signal Q is set to a value greater than the speed request signal P, the V/F of the output of the VVVF3 will be greater than the predetermined value when the internal pump 5 is started. , the internal pump 5 generates a large 1-lux when it is started. Therefore, as in the previous embodiment, without causing a decrease in plant output,
It becomes easy to restart the internal pump 5, and Plan 1
It is effective in improving the operating rate of ~.

Note that the present invention is not limited to the embodiments described above. For example, the V/F value at the time of restarting the internal pump may be determined as appropriate in a range larger than the V, /F value at steady state according to the necessary conditions such as The voltage control circuit controls the VV at startup.
Instead of increasing the output voltage of VF, the frequency control circuit may lower the output frequency of VVVF at startup. In addition, without departing from the gist of the present invention,
Various modifications can be made.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram schematically showing a driving device according to one embodiment of the present invention, and FIG. 2 is a circuit diagram schematically showing another embodiment. 1... Bus bar, 2... Input transformer, 3... Stationary variable voltage variable frequency power supply (VVVF), 4... Output transformer, 5... Reactor built-in reactor cooling Material recirculation pump (internal pump), 6.7, 9.10°11.
13.15.1B, 21.23... Electric circuit, 8... Frequency control circuit, 12... Voltage control circuit, 14... Instrument voltage transformer, 16... DC power supply, 17.20゜2
2...Switch. Applicant's agent Patent attorney Takehiko Suzue Figure 1 Figure 2

Claims (1)

[Scope of Claims] (1) In a drive device for driving a reactor coolant recirculation pump built into a nuclear reactor in a nuclear power plant, a static variable voltage that applies an output of a predetermined frequency and voltage to the recirculation pump. a variable frequency power supply circuit; a frequency control circuit for controlling the output of the power supply circuit to have a frequency F proportional to the speed request signal; and a frequency control circuit for controlling the output of the power supply circuit to have a voltage V proportional to the speed request signal. a voltage control circuit for controlling the recirculation pump; and a starting circuit for controlling the output of the power supply circuit when starting the recirculation pump so that the ratio V/F of the F and (2) is larger than a steady state value. A driving device for a reactor coolant recirculation pump built into a nuclear reactor, characterized by: (2) The startup circuit superimposes a predetermined signal on the speed request signal input to the voltage control circuit when starting the recirculation pump, and the speed corresponding to the signal input to the voltage control circuit is set to the speed request signal. The drive device for a reactor coolant recirculation pump built into a nuclear reactor according to claim 1, wherein the drive device controls the speed to be faster than the speed corresponding to the signal. (3) The activation device. The circuit causes the voltage control circuit to input a starting special voltage setting signal corresponding to a faster speed than the speed request signal that is input to the control circuit during normal operation, when the recirculation pump is started. A driving device for a reactor coolant recirculation pump built into a nuclear reactor according to claim 1.