JPH05196208A - Control of moisture separation heater - Google Patents

Abstract

PURPOSE:To interrupt heating without damaging a moisture separation heater at irregulanty of the moisture separation heater of a steam turbine of a thermal or atomic power generation plant or at the time of abnormality in the plant. CONSTITUTION:In the case where an alarm 28 is issued owing to abnromality 27 of a moisture separation heater, a manual interruption 20 signal is turned on, or in the case where a plant state signal 17 is turned on, a memory circuit 25 is set and a heating interruption signal 29 is turned on into a non-reheating operation. Thus, the non-reheating operation without damaging the moisture separation heater is enabled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steam turbine of a thermal power plant and a nuclear power plant, and more particularly to a steam turbine having a moisture separation heater for reheating high pressure turbine exhaust steam by using steam at an inlet of the high pressure turbine. The present invention relates to a method for controlling a moisture separation heater effectively used for

[0002]

2. Description of the Related Art As described in Japanese Patent Laid-Open No. 59-77012, the prior art is such that when the outlet steam temperature of a moisture separation heater exceeds a specified value, a detection signal from the detector causes The heating steam stop valve was fully closed.

[0003]

SUMMARY OF THE INVENTION The above-mentioned prior art is such that when the steam temperature at the outlet of the moisture separation heater exceeds a specified value or the high-pressure turbine exhaust pressure falls below a specified value, heating is performed by a detection signal from each detector. Although the steam stop valve is fully closed, when only the heating steam stop valve is fully closed, drainage and non-condensable gas discharge in the moisture separation heater become impossible,
There may be damage to the moisture separator heater. Also, the heating steam stop valve will be fully closed even if the detector fails, and if the heating steam stop valve is fully closed, the high pressure turbine exhaust steam will not be reheated, resulting in a decrease in output due to non-reheat operation. There's a problem. Further, even if the outlet temperature of the moisture separation heater becomes abnormal due to a failure of the detector, the heating steam stop valve may not be fully closed, and the moisture separation heater may be damaged.

As described above, due to the failure of the detector, there is a problem that the output is reduced or the moisture separation heater is damaged.

[0005]

[Means for Solving the Problems] To prevent damage to the moisture separation heater, drainage is performed by fully opening the drain valve in addition to fully closing the heating steam stop valve, and fully opening the condenser side vent valve and the feed water heater side. This can be achieved by fully closing the vent valve and discharging non-condensable gas.

In addition, the output is reduced due to a detector failure, or
To prevent damage from moisture separation heating, abnormal signals such as the outlet temperature of the moisture separation heater are multiplexed or an alarm is output, and the heating steam stop valve is fully closed, the drain valve is fully opened, and the condenser side vent is determined by the operator. This can be achieved by fully opening the valve and fully closing the vent valve on the feed water heater side.

[0007]

[Function] In order to prevent damage to the moisture separation heater and prevent output drop due to detector failure, the heating steam stop valve is fully opened,
Provide a common signal to fully open the drain valve, fully open the vent valve on the condenser side, and fully close the vent valve on the feed water heater side.The common signal is manually determined by the operator or by an abnormal signal from the multiplexed detectors. Turn it on.

[0008]

EXAMPLES Examples of the present invention will be described below.

First, the overall structure is shown in FIG.

The steam generated in the steam generator 1 enters a high pressure turbine 4 through a steam stop valve 2 and a steam control valve 3, and its exhaust gas is heated by a moisture separation heater 5 and is heated to a low pressure. It flows into the turbine 6 and drives the turbine and the generator 32. Turbine exhaust steam is the condenser 7
Is condensed in and becomes condensed water. Condensed water condensed in the condenser 7 is boosted by the feed / condensate pump 8 and heated by the feed water heater 9 by turbine extraction steam or the like and sent to the steam generator.

On the other hand, the steam branched from the upstream of the steam stop valve 2 passes through the heating steam stop valve 10 and passes through the heating steam control valve 1
1 or as heating steam through the heating steam control valve bypass valve 12 and is supplied to the moisture separation heater 5.

The moisture separator / heater 5 transfers heat by draining the drain accumulated in the heater header, the drain valve 13, the non-condensable gas in the heater chamber, and the partial scavenging steam. Vent piping provided to prevent supercooling due to in-pipe drainage and ensure a stable amount of steam, condenser side vent valve 14, feed water heater side vent valve 15, drain line of moisture separation heater, and It is composed of a heating steam system.

Next, the normal operation control of the moisture separation heater 5 will be described.

A control device 16 is provided to perform operation control, and the control device 16 includes the heating steam stop valve 10,
Heating steam control valve 11, heating steam control valve bypass valve 12,
The control functions of the drain valve 13, the condenser side vent valve 14, and the feed water heater side vent valve 15 are included, and the heating steam pressure 1
8, the low pressure turbine inlet temperature 19, the generator output signal 31, and the plant state signal 17 are input.

The control unit 16 controls the heating steam by the signals of the heating steam pressure 18 and the generator output 31, and the drain valve 13 is fully opened at the low load and fully closed at the high load by the signal of the generator output 31. The vent line, when the load is low, fully opens the condenser side vent valve 14, fully closes the feed water heater side vent valve 15,
When the load is high, the condensate side vent valve 14 is fully closed, the feed water heater side vent valve 15 is fully opened, and the heating steam control valve bypass valve is controlled to be fully closed at low load and fully open at high load.

As described above, the moisture separation heater reheats the high-pressure turbine exhaust steam by passing the heating steam, but operates only by the function of separating the moisture without passing the heating steam. Non-reheat operation is also possible. When this non-reheat operation is performed, the heating steam stop valve 10 is fully closed, the heating steam control valve 11 is fully closed, and the heating steam control valve bypass valve 12 is fully closed to completely shut off the heating steam and to drain the drain valve 13
The drain is discharged fully, the condenser-side vent valve 14 is fully opened, and the feedwater heater-side vent 15 is completely closed to discharge the non-condensable gas and the operation is performed.

Next, a first embodiment of the control method of the present invention will be described with reference to FIG.

When the moisture separation heater is abnormal or the plant is abnormal, the moisture separation heater is set to the non-reheat operation and the plant is operated without damaging the moisture separation heater and the turbine. Will be done.

FIG. 2 shows a method of operating the moisture separation heater in non-reheat operation.

In order to bring the moisture separation heater into non-reheat operation, the heating stop signal 29 is turned on to fully close the heating steam stop valve 10, fully close the heating steam control valve 11 and bypass the heating steam control valve. Non-reheat operation can be achieved by fully closing the valve 12, fully opening the drain valve 13, fully opening the condenser side vent valve 14, and fully closing the feed water heater side vent valve 15.

In order to turn on the heating stop signal 29,
This is to turn on the OR circuit 24 for the signal that sets the memory circuit 25. The OR circuit 24 is a circuit that is turned on when one or more signals input to the circuit are turned on. Therefore, the signal that needs to be in non-reheat operation is O
By inputting to the R circuit 24, non-reheat operation can be performed.

A signal for turning on the OR circuit 24 will be described.

The signal of the manual stop 20 is a signal which can be turned on by the judgment of the operator and is constituted by an operation switch. Therefore, in any operating state, non-reheat operation can be performed at the operator's discretion.

Therefore, process abnormality 2 related to the moisture separation heater
7 occurs, an alarm 28 is output to inform the operator of the abnormality of the moisture separator / heater, and the operator monitors the operating state and process values of the plant and the moisture separator / heater to detect the moisture separator / heater or steam. The signal for the manual stop 20 can be turned on to put the moisture separator heater into non-reheat operation, such as when the turbine may be damaged.

The following signals, the plant status signal 17, are composed of signals of the turbine trip 21, the generator trip 22, and the load cutoff 23. The signal of the plant state signal 17 turns on when the load on the steam turbine suddenly decreases and the plant is abnormal. When the plant is abnormal, the heating steam of the moisture separation heater must be rapidly reduced, and the drain discharge and non-condensable gas discharge in the moisture separation heater cannot be discharged to the feed water heater. In addition, it is necessary to switch to the condenser side. For that reason,
When the signal of the plant state signal 17 is turned on, the OR circuit 24 is turned on to bring the moisture separation heater into non-reheat operation.

Next, the memory circuit 2 for turning on the signal 29
No. 5 is set when the OR circuit 24 is turned on, and the set state is continued even when the OR circuit 24 is turned off, and the non-reheat operation is maintained. This is because the non-reheat operation is forcibly performed, and the release is performed by the operator's judgment. Therefore, the (R) lamp 30 can be turned on and the memory circuit 25 can be reset by the manual stop reset 26 so that it can be determined that the memory circuit 25 is in the set state. The signal of the manual stop reset 26 is a signal that can be turned on by the operator's judgment, and is constituted by an operation switch.

The memory circuit 25 is prioritized for the set signal. When the set signal is on, the memory circuit 25 continues to be in the set state even when the reset signal is turned on. When the set signal is off, the memory circuit 25 is reset by turning on the reset signal. It is a circuit that becomes.

Next, a second embodiment of the present invention will be described with reference to FIG.

In FIG. 3, the process anomalies 27a, 27b and 27c related to the moisture separation heater are multiplexed with 3 signals to be 2/2.
3 is input to the circuit 33. The 2/3 circuit 33 is a circuit which is turned on when two or more signals among the three signals are turned on. Therefore, even if one of the detectors for detecting the process abnormality related to the moisture separation heater fails, for example, even if only 27a is turned on, 2
Since 7b and 27c remain off, the 2/3 circuit remains off and the heating stop signal 29 is also off. Therefore, the detector does not become non-reheat operation and the output does not decrease.
If a process related to the moisture separation heater is abnormal,
If two or more signals 27a, 27b and 27c are turned on, 2
The / 3 circuit 33 is turned on, the heating stop signal 29 is turned on, and non-reheat operation is performed. Therefore, for example, even if 27a remains off due to a failure, 27b and 27c are turned on, so 2/3
The circuit is on and can be in non-reheat mode.

As described above, the abnormality of the moisture separation heater, or
When the plant is abnormal, the steam for heating the moisture separation heater is cut off, and drainage discharge and non-condensable gas discharge are performed for non-reheat operation to prevent damage to the moisture separation heater and steam turbine. .. Further, it is possible to prevent a decrease in output or damage to the moisture separation heater due to a failure of a detector that detects a process abnormality related to the moisture separation heater.

[0031]

According to the present invention, in a steam turbine having a moisture separation heater, non-reheat operation can be performed without damaging the moisture separation heater, and a moisture separation heater can be used. By performing non-reheat operation even when an abnormality occurs, it is possible to continue the plant operation without affecting the moisture separation heater and the steam turbine.

[Brief description of drawings]

FIG. 1 is a system diagram of an embodiment of the present invention.

FIG. 2 is a flowchart for stopping heating of a moisture separation heater.

FIG. 3 is a flowchart for stopping the heating of the moisture separation heater.

[Explanation of symbols]

16 ... Control device, 20 ... Manual stop, 24 ... OR circuit, 2
5 ... Memory circuit, 29 ... Heating stop signal.

Claims (3)

[Claims] 1. A steam generator, a high-pressure turbine driven by the steam generated by the steam generator, and a part of the inlet steam of the high-pressure turbine used as a heating source to reheat the exhaust gas of the high-pressure turbine. Separation heater, low-pressure turbine driven by reheated steam, heating steam stop valve for shutting off heating steam of the moisture separation heater, heating steam control valve and heating steam control valve for adjusting the amount of heating steam A bypass valve, a drain valve for discharging the drain in the moisture separator / heater, a condenser side vent valve for ensuring a stable amount of steam in the moisture separator / heater, and a feed water heater side drain valve. , The heating steam stop valve, the heating steam control valve, the heating steam control valve bypass valve,
In a steam turbine equipped with a drain valve, a vent valve (condenser), and a control device for controlling the vent valve, when abnormality occurs in the moisture separator / heater, the reheat of the exhaust steam of the high-pressure turbine is stopped. A method for controlling a moisture separation heater, comprising: 2. The method for controlling a moisture separation heater according to claim 1, wherein, when an abnormality occurs in the plant, the reheat of the exhaust steam of the high-pressure turbine is stopped. 3. The method for controlling a moisture separation heater according to claim 1, wherein the reheating of the exhaust steam of the high-pressure turbine can be arbitrarily stopped regardless of the plant state.