JPH0643803B2 - Steam turbine controller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a steam turbine control device for obtaining a quick and stable starting characteristic.

(Prior Art) Although a steam turbine plant has a steam generation source, it is necessary to drive an oil pump from the turbine without having another hydraulic power source or auxiliary power source for turbine control or lubrication. There is a method of self-sufficient oil for control and lubrication of the turbine itself. This type of turbine plant includes, for example, a geothermal power plant that has only a DC power supply that can be used for a short period of time such as a drive signal, a turbine for supplying backup power in an emergency, and an emergency backup for a nuclear power plant. Reactor isolation cooling system (hereinafter referred to as RC
There is an RCIC turbine pump system used in the IC).

Hereinafter, the steam turbine system to which the present invention is applied will be referred to as RC
The IC turbine system will be described as a typical example. RCIC is an atom for maintaining the water level of the reactor by supplying cooling water from the condensate storage tank to the reactor when the reactor is isolated from the turbine condenser and for cooling the core. It is a reactor auxiliary facility and has a system configuration as shown in Fig. 3.

In FIG. 3, RCIC is provided as an auxiliary facility for the nuclear reactor 2 housed in the containment vessel 1 having the pressure suppression pool 7. The steam generated in the reactor 2 is branched from the main steam line 4 and is passed through the RCIC steam line 8 having an electric valve 9, a steam stop valve 10 and a steam control valve 11 to the RCI.
It is guided to a C turbine (hereinafter simply referred to as turbine) 12 and drives it. The exhaust gas that has driven the turbine 12 is returned to the pressure suppression pool 7 attached to the reactor 2 via the steam turbine exhaust line 15. The main steam line is branched and connected to the pressure control pool 7 through the relief safety valve 6 in the containment vessel 1.

Water supply to the reactor 2 is performed via a water supply line 5. The shaft of the turbine 12, that is, the RCIC turbine drive shaft (hereinafter,
A turbine shaft 14) is provided with an RCIC feed pump (hereinafter referred to as feed pump) 13 for supplying cooling water from the condensate storage tank 3 to the reactor 2, and an oil for supplying lubricating oil to a turbine control device (not shown). Pump 16 is directly connected.

In the RCIC configured as described above, the reactor 2 is isolated and the reactor water level is lowered in an emergency such as when the reactor water supply is stopped in the reactor power generation system.
Starts to open, and the turbine 12 is started by passing the reactor steam through the steam stop valve 10 and the steam control valve 11 that are already waiting in the open state.
It has the function of driving 13 to supply cooling water from the condensate storage tank 3 to the reactor 2 to cool the core. Due to this function, the water supply pump 13 must supply a predetermined amount of water and supply the cooling water to the reactor 2.
When the 12RCIC start signal is received, it must start as quickly as possible and enter stable operation.

FIG. 4 shows a control device of the turbine 12. RC
When an IC start command is issued and the motor-operated valve 9 starts to open, steam flows into the turbine 12 through the steam stop valve 10 and the steam control valve 11 that are already in the fully opened state, and the turbine 12
Already mentioned that will start. At the same time when the turbine 12 is started, the oil pump 16 directly connected to the turbine 12 is driven, and when it reaches or exceeds a predetermined rotation speed, the pressure of the control oil 32 fed from the oil pump 16 is established, and the electro-oil converter 31 and the oil The steam control valve 11 can be controlled via the cylinder 33.

Further, during normal operation, in order to control the discharge flow rate of the water supply pump 13 at a constant level, for example, a differential pressure transmitter type flow rate detector 19 is provided on the discharge side of the water supply pump 13, and the output of the flow rate signal 19 is provided.
A and the set flow rate 20a output from the flow rate setter 20 are guided to the deviation calculator 21, and from there, the flow rate deviation signal 22 representing the difference between the set flow rate and the actual flow rate is sent to the target speed signal calculator 25. The target speed signal calculator 25 forms a target speed signal 26 for making the flow rate deviation zero and sends it to the speed control calculator 29.

The speed control calculator 29 uses the speed calculator 27 based on the output pulse of the speed detector consisting of the speed detection gear 17 attached to the turbine shaft 14 and the electromagnetic pickup 18 arranged opposite to the speed detection gear 17. The actual speed signal 28 representing the obtained actual speed is also introduced as a feedback signal of the speed control minor loop, and here, the deviation of both input signals, that is, the speed target signal 30 for making the deviation between the target speed and the actual speed zero It is formed and sent to the electro-oil converter 31 to control the opening / closing of the steam control valve 11.

A ramp signal generator 23 is provided so as to keep the rate of acceleration, that is, the acceleration, constant when the turbine 12 is started. The ramp signal generator 23 is connected by a limit switch provided in the motor-operated valve 9 at the beginning of opening the motor-operated valve 9. It is started by the start signal 34,
A calculator that calculates the ramp signal 24 that increases with a predetermined slope over time
Send to 37. Similarly, the idle signal 36 from the idle signal calculator 35, which is activated by the start signal 34, is supplied to the calculator 37.
Is also entered. The idle signal 36 is for giving the speed value of the ramp signal 24 at time zero (immediately after the start of startup), that is, the idle speed value, and the calculator 37 uses the ramp signal 24 and the ramp signal 24 to set the target value according to the desired ramp function. Ramp signal
38 is made and sent to the target speed signal calculator 25. The target speed signal calculator 25 always selects a low-value signal from the speed signals corresponding to the target ramp 38 and the flow rate deviation signal 22 to form the target speed signal 26.

(Problems to be Solved by the Invention) These relationships are shown in FIG. Since the turbine 12 was not started before the RCIC start command, the water supply pump 13
The discharge flow rate is zero, and the flow rate deviation signal 22 outputs a 100% output signal, so the target ramp signal 38, which has a low value, is prioritized by the start signal 34, and the turbine speed 49 also follows the target ramp signal 38. Thus, the steam control valve 11 is controlled, and the turbine speed follows. The flow rate deviation signal 22 is the actual flow rate 50
Is gradually decreased from 10% toward the flow rate set value 20a from the point at which is started to switch to the flow rate controller at the intersection with the target ramp signal 38.

Therefore, the purpose of the RCIC turbine is to supply the cooling water to the reactor 2 as quickly as possible and to start stable operation is determined only by the setting of the ramp signal generator 23, and the supply time of the cooling water cannot be shortened. It was in a state.

It is an object of the present invention to provide a more stable steam turbine control device that does not rely on the ramp function generator described above and further shortens the time for securing the flow rate.

[Configuration of Invention] (Means and Action for Solving Problems) A steam turbine control device according to the present invention detects a pressure of a steam source of a steam turbine and sets a target speed by the pressure detected by the pressure detector. A target speed setter to be created is added, and when the turbine is started, the signal from this target speed setter is prioritized and the signal of the target speed setter based on this furnace pressure and the flow deviation signal are compared and calculated. It is characterized by switching at the point where it reaches inside.

In the present invention, when the deviation between the target speed setting signal corresponding to the pressure of the steam source and the flow rate deviation signal is within a predetermined value,
The bias device is configured to raise the target speed setting signal by the upper limit value. Therefore, stable control characteristics can be obtained, and the flow rate securing time can be significantly shortened.

(Example) The present invention will be described below with reference to an example shown in FIG.
In FIG. 1, the same reference numerals as those in FIG. 4 indicate the same parts, and the description thereof will be omitted.

The difference between the controller according to the present invention shown in FIG. 1 and the conventional controller shown in FIG. 4 is that the conventional ramp function signal generator 23 is used.
In the present invention, the reactor pressure detection for detecting the pressure of the reactor 2 which is the steam source is utilized by utilizing the feature that the required command value to the steam turbine changes from the function of the system head of the RCIC system according to the reactor pressure. The point is that the container 40 is provided.

Further, the feedwater outflow start rotation speed of the feedwater pump 13 obtained by the reactor pressure signal 42 is created, and this feedwater outflow start rotation speed is used as the target speed setting device 43, and the target speed setting signal 44 and the flow rate deviation signal 22 are This is in the point of calculation by the calculator 46.

Further, since the flow rate deviation signal 22 is switched when the deviation signal 47 obtained by the calculator 46 reaches a certain setting, an adder 45 is provided between the target setting signal 44 and the target speed ratio calculator 25. The point is that the flow rate deviation signal of the flow rate controller is switched by setting the target speed signal 44 to the upper limit value by the bias device 48.

Next, the operation of the steam turbine control device of the present invention configured as shown in FIG. 1 will be described with reference to FIGS. 1 and 2. FIG. 2 shows the operating state according to the present invention. The flow deviation signal 22 from the calculator 21 of the flow controller system is
As in the conventional case, the flow rate is zero before the start command, so the output signal is 100% .However, the target mark setting signal 44 of the target speed setter 43
Is set to a value corresponding to the actual flow rate starting rotation speed, the turbine rotation speed 49 is increased by the start command 34 and settles to the target speed setting signal 44.

After that, since the flow rate deviation signal 22 decreases toward the rated point when the actual flow rate 50 starts to be output with the first delay, the target speed setting signal 44 and the flow rate deviation signal 22 have substantially the same value. Then, the deviation signal 47 is operated within a certain setting by the calculator 46,
Since the target speed setting signal 44 is raised by the bias device 48 to the upper limit value as shown in FIG. 2, stable control characteristics can be obtained and the flow rate securing time can be greatly shortened.

As described above, according to the present invention, when the deviation between the target speed setting signal corresponding to the pressure of the steam source and the flow rate deviation signal reaches a predetermined value, the target speed setting signal is raised to the upper limit value. With this configuration, stable control characteristics can be obtained, and the time required to secure the flow rate with respect to the steam source can be significantly shortened.

[Brief description of drawings]

FIG. 1 is a block system diagram showing an embodiment of a steam turbine control device of the present invention, FIG. 2 is a turbine start-up characteristic diagram for explaining the operation of the present invention, and FIG. 3 is a reactor isolation in a reactor power plant. 4 is a block system diagram showing a conventional steam turbine control device, and FIG. 5 is a turbine starting characteristic diagram thereof. 2 ... Reactor (steam source), 11 ... Steam control valve 12 ... RCIC turbine, 13 ... Water supply pump 16 ... Oil pump, 19 ... Flow rate detector 20 ... Flow rate setter, 21 ... Deviation Calculator 22 …… Flow rate deviation signal, 25 …… Target speed calculator 26 …… Target speed signal, 27 …… Speed calculator 30 …… Speed signal, 31 …… Electro-hydraulic converter 34 …… Start signal, 40… … Furnace pressure detector 42 …… Furnace pressure signal, 43 …… Target speed setter 44 …… Target speed setting signal, 45 …… Adder (switch) 46 …… Arithmetic unit, 47 …… Deviation signal 48 …… Bias device

Claims (1)

[Claims] 1. An oil pump for supplying at least control oil used in a control unit for controlling the steam control valve to a steam turbine driven by steam supplied from a steam source through the steam control valve, At least a water supply pump for supplying waste water to the steam source is connected, and the steam turbine speed is controlled so that the discharge flow rate of the water supply pump becomes a predetermined value given from a flow controller by a start command. In a steam turbine control device including a speed controller for controlling, a target speed setting device that detects a pressure of a steam source to which the cooling water is supplied and sets a target speed corresponding to the pressure, and the target speed setting device And a flow rate deviation signal from the flow rate controller, and a calculator for calculating a deviation between the signal and a flow rate deviation signal from the flow rate controller. Steam turbine characterized by comprising an adder for switching the signal of the speed setting device to the flow deviation signal from the flow controller, and a bias device for applying a bias to the signal of the target speed setting device upon completion of the switching. Control device.