JPH0366486B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a bypass system control device for a steam turbine plant, and in particular, the present invention relates to a bypass system control device for a steam turbine plant. The present invention relates to a bypass system control device for a steam turbine plant that can completely prevent high-temperature steam from flowing into a condenser.

[Technical background of the invention]

Generally, in nuclear power plants and thermal power plants, the main steam generated from the nuclear reactor or boiler is routed through the main steam pipe as shown in Figure 1.
The steam is guided to the steam turbine 4 through the main steam stop valve 2 and the steam control valve 3, and after performing expansion work, flows into the condenser 5 where it is cooled and becomes condensate.
The main steam line 1 and the condenser 5 are directly connected by a bypass pipe 6 that bypasses the steam turbine 4, and the bypass valve 7 is opened by a valve drive device 8 in the event of an emergency such as a system load or power outage. The main steam in the main steam pipe 6 is directly routed to the condenser 5 without passing through the steam turbine 4.
This prevents the steam turbine 4 from overspeeding, protects the nuclear reactor or boiler, and provides flexibility in the operation of the power plant. In addition, the bypass valve 7
are opened and closed even when the plant is started up, to stabilize the steam pressure generated by the reactor and boiler. Further, this bypass valve 7 is periodically tested for opening and closing, and a constant check is made to ensure that the bypass valve 7 does not open during an emergency or startup of the plant.

Further, the bypass pipe 6 is provided with a temperature reducing device 9 on the downstream side of the bypass valve 7, and high-temperature steam flows into the condenser 5 during plant emergencies, startup, and opening/closing tests of the bypass valve 7. We are trying to prevent this from happening. This temperature reducing device 9 includes a pressure reducing section 12 equipped with a multi-stage orifice 11 and a cooling water supply pipe 13.
A cooling water valve 15 is provided in the middle of the cooling water supply pipe 13. Conventionally, the cooling water valve 15 is operated by a signal from the limit switch 16 of the bypass valve 7. When the limit switch 16 senses the start of the opening operation of the bypass valve 7, the cooling water valve 15 is activated by the limit switch 16. A valve open signal is issued to the water valve 15.

[Problems with background technology]

However, according to such a conventional response system,
At the beginning of the opening operation of the bypass valve 7, the supply of cooling water was delayed, and the temperature reduction effect of the temperature reduction device 9 became insufficient, albeit for a short time. As a result, high-temperature steam temporarily flows into the condenser 5, and the inside of the condenser 5 is exposed to the high-temperature steam, resulting in damage or destruction and shortening the service life.

[Purpose of the invention]

In view of these points, the present invention prevents the supply of cooling water from being delayed at the beginning of the opening operation of the bypass valve, and in the event that the opening operation of the cooling water valve is not performed at the same time as the opening operation of the bypass valve. In this case, the cooling water valve is reliably opened using the bypass valve opening signal, etc., and high-temperature steam is completely prevented from flowing into the condenser through the bypass pipe, thereby protecting the condenser. The purpose is to obtain a bypass system control device that can perform the following steps.

[Summary of the invention]

In order to achieve the above object, the bypass system control device according to the present invention includes a dual valve opening operation signal generation circuit that simultaneously issues a valve opening signal to the bypass valve and the cooling water valve in response to a system operation request signal, and a bypass valve opening operation start circuit. and a cooling water valve opening signal generation circuit that generates a valve opening signal to the cooling water valve in response to either the signal, the bypass valve position signal, or the condenser internal temperature detection signal. Even if the operation signal generation circuit does not issue a valve open signal to the cooling water valve, the valve open signal is generated from the operation signal generation circuit to the cooling water valve.

[Embodiments of the invention]

Embodiments of the present invention will be described in detail below with reference to the drawings.

In FIG. 2, in which the same components as those in the conventional steam turbine bypass system shown in FIG. A bypass system operation request signal S ₁ , S ₂ , or S ₃ is applied to simultaneously open the bypass system. That is, an emergency activation signal S ₁ is input to the bypass system control device 21 in the event of an emergency such as a power outage, and a startup stabilization signal S ₂ for stabilizing the steam pressure is input at the time of plant startup. Further, when performing an opening/closing test of the bypass valve 7, a bypass valve operation test signal _S3 is input. And these signals S ₁ ,
When S ₂ and S ₃ are received, valve open signals are simultaneously issued from the bypass system control device 21 to the bypass valve 7 and the cooling water valve 15, respectively.

Furthermore, cooling water valve operation request signals S ₄ , S ₅ , S ₆ for opening the cooling water valve 15 are input to this bypass system control device 21 , and the bypass system operation request signals S ₁ , S ₂ , Even if the cooling water valve 15 fails to open due to S ₃ , the cooling water valve 15 will be reliably opened by the cooling water valve operation request signals S ₄ , S ₅ , and S ₆ . These cooling water valve operation request signals S ₄ , S ₅ , and S ₆ are the bypass valve opening operation start signal S ₄ from the limit switch 16 that detects the opening operation of the bypass valve 7, and the valve opening of the bypass valve 7 as well. from the bypass valve position signal S ₅ from the valve position detector 17 that detects the flow of high-temperature steam into the condenser 5 and the condenser internal temperature detection signal S ₆ that is emitted from the temperature sensor 18 that detects the inflow of high-temperature steam into the condenser 5. It's getting old,
Even when the cooling water valve 15 is not opened by the bypass system operation request signals S ₁ , S ₂ , S ₃ , the bypass system control device 21 releases the cooling water based on these signals S ₄ , S ₅ , S ₆ . A valve opening signal is issued to the valve 15.

The internal circuit of the bypass system control device 21 will be explained below.

As shown in FIG. 3, the bypass system control device 21 includes a both valve opening signal generation circuit 22 and a cooling water valve opening signal generation circuit 23.

First, the both valve opening operation signal generation circuit 22 is provided with a valve opening timing setting device 24 that sets the operation timing of the system. This valve opening timing setting device 24
consists of a comparator 25 and a bias signal generator 26, and the system operation request signals S ₁ , S ₂ , S ₃ applied to the comparator 25 are compared with the bias signal S ₇ from the bias signal generator 26 . and when the deviation between both signals exceeds a certain value, valve open instruction signals _S8 and _S9 are issued to the bypass valve open operation signal generator 27 and the cooling water valve open operation signal generator 28, respectively. ing. In this embodiment, the bias signal S ₇ is set to zero, and as soon as any of the system operation request signals S ₁ , S ₂ , S ₃ is input, the valve opening instruction signals S ₈ , S ₉ are activated. It is beginning to be emitted.

Further, the bypass valve opening operation signal generator 27 is provided with a comparator 29, and the comparator 29 outputs the valve opening instruction signal _S8 and the bypass valve position signal _S5 from the valve position detector 17. are compared, and a deviation signal _S10 of both values is sent to the bypass valve 7 through an amplifier 31 as a bypass valve opening signal _S11 . Note that the system operation request signal S ₁ ,
Initially, when S ₂ and S ₃ are issued, the bypass valve 7 is fully closed, and the bypass valve position signal S ₅ is zero, so a signal instructing the bypass valve to fully open is first output to the bypass valve 7. When the bypass valve 7 is completely opened, the bypass valve position signal _S5 becomes the valve opening instruction signal.
_S8 , and the output of the bypass valve opening signal _S11 is stopped.

On the other hand, the cooling water valve opening operation signal generator 28 is provided with a signal generator 32 having a function of generating a cooling water valve opening signal _S12 .
A normally open contact 33 is provided in the signal transmission circuit connecting the cooling water valve 15 and the cooling water valve 15 .

Further, a switching signal generator 34 is provided which operates the normally open contact 33, and this switching signal generator 34 receives the valve opening instruction signal _S9 from the valve opening timing setting device 24 and operates the normally open contact 33. Close side switching signal to close
It has the ability to emit S ₁₃ .

Next, the cooling water valve opening operation signal generation circuit 23 is provided with a signal generator 35 having a function of generating a cooling water valve opening signal _S12 , and also connects this signal generator 35 and the cooling water valve 15. Three normally open contacts 36, 37, 38 are arranged in parallel with each other in the signal transmission circuit. Furthermore, a switching signal generator 3 actuates these three normally open contacts 36, 37, 38.
9, 40, 41 are provided, and these switching signal generators 39, 40, 41 open the normally open contacts 36, 41 when receiving the cooling water valve operation request signals _S5 , _S4 , _S6, respectively. Close side switching signal that closes 37 and 38
It has the function of emitting S ₁₄ , S ₁₅ , and S ₁₆ .

In such a bypass system control device 21, as described above, the system operation request signal
When S ₁ , S ₂ , and S ₃ are input, the bypass valve open signal S ₁₁ and the cooling water valve open signal S ₁₂ are simultaneously generated from the double valve opening operation signal generation circuit 22, and the bypass valve 7 and the cooling water valve 15 are activated. will be opened at the same time. This results in
When the bypass system is activated, the high-temperature steam that has passed through the bypass valve 7 is reliably cooled by the temperature reducing device 9, and high-temperature steam is prevented from flowing into the condenser 5. Even in the unlikely event that the cooling water valve 15 does not open, the opening operation of the bypass valve 7 causes the cooling water valve opening operation signal generation circuit 23 to receive the cooling water valve operation request signal S ₄ from the limit switch 16 and valve position detector 17. Since S ₅ is being applied, a valve open signal S ₁₂ is issued to the cooling water valve 15.
That is, for example, when the bypass valve is opened, the cooling water valve operation request signal _S5 from the valve position detector 17 is input to the switching device 39, a switching signal _S14 is generated, and the contact 36 is closed. Therefore, the valve opening signal _S12 from the cooling water opening operation signal generator 35 is applied to the cooling water valve 15, and its opening operation is performed. Furthermore, if the cooling water valve 15 still does not open, the cooling water valve operation request signal _S6 from the condenser 5 is applied to the cooling water valve opening operation signal generation circuit 23, and the valve opening signal _{S12 is} applied.
is output to the cooling water valve 15, and high temperature steam is output to the condenser 5.
It is possible to completely prevent it from flowing into the interior.

The embodiment shown in FIG. 4 is one in which a plurality of bypass valves 7 and temperature reducing devices 9 are provided in parallel, and the same components as in the embodiment described above are indicated by the same reference numerals. That is, the bypass pipe 6 is
It is branched into main pipes, each branch pipe 6-1, 6-2,
Bypass valves 7-1, 7- for ..., 6-n, respectively
2,...,7-n and temperature reducing devices 9-1, 9-2,...,
9-n are provided. Further, the branch pipes 6-1, 6-2, ..., 6-n are connected to the condenser 5, and the temperature detector 1 is connected to the branch pipes 6-1, 6-2, ..., 6-n.
8-1, 18-2,..., 18-n are attached.

The bypass system control device 31 that controls multiple sets of valves can basically be configured by combining multiple sets of valves shown in FIG. They will be released in sequence. That is, in FIG. 5, in which the same components as in FIG. 3 are indicated by the same symbols, n sets of control units are arranged in parallel, and the emergency operation signal _S1 of the system operation request signals and the start stabilization signal are All other signals except signal _S2 are arranged to enter and exit in each group. The emergency activation signal S ₁ and the activation stabilization signal S ₂ (indicated by one signal line in FIG. 5 to simplify the drawing) are respectively applied to the comparator 25 of each control unit. However, the signal lines are combined into one, so that outputs are sent to all comparators 25 at the same time. However, the bias signals S ₇ -1, S 7 -2, ..., S ₇ generated from the bias signal generators 26-1, _26-2 , ..., 26-n of each control unit are
The output value of -n is set to increase in order according to a certain rule, and the output value of each comparator 25-1, 2
Valve opening instruction signals S ₈ -1, S 8 -2,..., S ₈ -n and S ₉ -1, S ₉ output from 5-2,..., ₂₅ -n
The output timings of -2,..., S ₉ -n are shifted from each other according to a certain rule. That is, when the emergency activation signal S ₁ and the start stabilization signal S ₂ are output, the number of bypass valves 7 and cooling water valves 15 proportional to the magnitude of the output values of the signals S ₁ and S ₂ are opened. It's getting old. FIG. 6 shows the opening operation of the bypass valve 7. As the output values (horizontal axis) of the system operation request signals S ₁ and S ₂ gradually increase, the bypass valve 7-1 first opens. As the opening degree (vertical axis) increases, this bypass valve 7-1
When the bypass valve 7-2 becomes fully open, the bypass valve 7-2 starts to open at the same time, and this process is repeated sequentially up to the bypass valve 7-n.

Note that the other valve opening operations are performed independently for each group, and the operations are exactly the same as in the embodiment described above.

〔Effect of the invention〕

As described above, the bypass system control device according to the present invention includes a dual valve opening signal generation circuit that simultaneously issues valve opening signals to the bypass valve and the cooling water valve in response to a system activation request signal, and also includes a dual valve opening signal generation circuit that simultaneously issues valve opening signals to the bypass valve and the cooling water valve. As a safety circuit of the signal generation circuit, bypass valve opening operation start signal, bypass valve position signal,
Alternatively, we have installed a cooling water valve opening signal generation circuit that issues a valve opening signal to the cooling water valve based on one of the condenser internal temperature detection signals, so the cooling water valve is always opened when the system is operating. This allows the temperature reduction device to function reliably, completely prevents high-temperature steam from flowing into the condenser, and protects the condenser extremely well.

[Brief explanation of drawings]

FIG. 1 is a system explanatory diagram of a general steam turbine bypass system, FIG. 2 is a system explanatory diagram of a steam turbine bypass system in an embodiment of the present invention,
FIG. 3 is a circuit explanatory diagram of a bypass system control device in one embodiment of the present invention, FIG. 4 is a system explanatory diagram of a steam turbine bypass system in another embodiment of the present invention, and FIG. 5 is shown in FIG. FIG. 6 is a circuit explanatory diagram of a bypass system control device that controls a steam turbine bypass system, and FIG. 6 is a diagram showing an opening operation of a bypass valve. 7... Bypass valve, 9... Temperature reduction device, 15...
Cooling water valve, 21, 31...Bypass system control device, 22...Both valve opening operation signal generation circuit, 23...
...Cooling water valve opening signal generation circuit, S ₁ , S ₂ , S ₃ ...
System operation request signal, S ₄ , S ₅ , S ₆ ...Cooling water valve operation request signal.

Claims (1)

[Claims] 1. In a bypass system control device for a steam turbine plant that controls valves in a bypass system arranged to bypass a steam turbine, an emergency activation signal issued when a system load is interrupted, and a steam The cooling water of the bypass valve and temperature reducing device is controlled by either the startup stabilization signal issued to stabilize the generated pressure or the bypass valve operation test signal issued to perform the opening/closing test of the bypass valve. A dual valve opening signal generation circuit that simultaneously outputs valve opening signals for the valves, and a valve opening signal generation circuit for the cooling water valve that outputs a bypass valve opening operation start signal, a bypass valve position signal, or a condenser internal temperature detection signal. 1. A bypass system control device for a steam turbine plant, comprising: a cooling water valve opening signal generation circuit that outputs an opening signal. 2. The double valve opening operation signal generation circuit includes a valve opening timing setting device that issues a valve opening instruction signal when the output of the system operation request signal exceeds a set value, and a valve opening instruction signal from this valve opening timing setting device. The steam turbine plant according to claim 1, further comprising a bypass valve opening signal generator and a cooling water valve opening signal generator, which generate bypass valve and cooling water valve opening signals in response to the received signal. Bypass system controller. 3 A plurality of sets of both valve opening operation signal generation circuits and cooling water valve opening operation signal generation circuits are provided, and each setting value set in the valve opening timing setter of each set of both valve opening operation signal generation circuits is different from each other. A bypass system control device for a steam turbine plant according to claim 2, characterized in that: 4. The cooling water valve open operation signal generation circuit generates a cooling water valve operation request signal through a valve open signal generator, a normally open contact provided in a signal transmission circuit connecting the valve open signal generator and the cooling water valve, and a cooling water valve operation request signal. 2. The bypass system control device for a steam turbine plant according to claim 1, further comprising a switching signal generator that receives the switching signal and generates a closing switching signal to the normally open contact. 5. The double valve opening signal generation circuit includes a bypass signal valve opening signal generator, and the cooling water valve opening signal generation circuit has a normally open signal in the signal transmission circuit connecting the valve opening signal generator and the cooling water valve. A bypass valve control device for a steam turbine plant according to claim 1, further comprising a contact point. 6. The cooling water valve open operation signal generator includes a valve open signal generator, a normally open contact provided in parallel with the normally open contact of the cooling water valve open operation signal generation circuit, and a switching signal to the normally open contact. 6. The bypass system control device for a steam turbine plant according to claim 5, further comprising a switching signal generator that emits a switching signal generator.