JPH0734809A - Temperature control device of extraction steam turbine - Google Patents

Abstract

PURPOSE:To control the temperature of each steam discharged from a high pressure part upstream of and from a low pressure part downstream of an extraction regulating valve to the prescribed value which does not adversely affect the strength and vibration of the turbine when the extraction steam turbine is operated with low load after the load dump. CONSTITUTION:The deviation signal between the detected temperature of the discharge steam from a high pressure part 2 by an extraction temperature detector 16 and the target value of the prescribed temperature, and the deviation signal between the detected temperature of the discharge steam from a low pressure part 3 by a discharge temperature detector 17 and target values of each prescribed temperature are outputted at an extraction temperature regulator 21 and a discharge temperature regulator 22 respectively. These deviation signals are received by a steam regulating valve controller 1 3 and an extraction regulating valve controller 14 of a governor 12 to control a steam regulating valve 6 and an extraction regulating valve 7 to control the steam flow rate in the high pressure part 2 and the low pressure part 3 respectively, and the temperature of the discharge steam from the high pressure part 2 and the low pressure part 3 is controlled to the prescribed value respectively.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a temperature control device for an extraction steam turbine, which controls the temperature of each exhaust steam from a high pressure part upstream and a low pressure part downstream of an extraction control valve when the load of the extraction steam turbine is low. Regarding

[0002]

2. Description of the Related Art In an extraction steam turbine, a steam control valve is provided at the turbine inlet, and an extraction control valve is provided at the extraction section. In a thermal power generation facility, a generator is connected to this extraction steam turbine. In such a thermal power generation facility, the flow rate of steam from the boiler is controlled by the steam control valve to flow into the turbine to drive the turbine, and the electric power generated by the generator is supplied to the power system, while the extraction control valve is used. The extraction pressure is controlled to supply extraction steam to the outside.

By the way, after the load is cut off when the power supply to the power system is cut off, the extraction steam turbine is operated at a low load, and a low load power is supplied to the power system. In this case, the bleed air control valve is operated with the valve fully closed or fully opened.
A small amount of steam flows in the high-pressure portion including the blade stages upstream of the extraction control valve and the low-pressure portion including the blade stages downstream of the extraction control valve.

[0004]

In the low load operation performed after the load is cut off as described above, a small amount of steam flows in the high pressure portion upstream of the extraction control valve and the low pressure portion downstream of the extraction control valve of the extraction steam turbine. Therefore, the minimum flow rate required to cool the inside of the turbine may not be reached. When such a case is continuously operated for a long time, the temperature of the exhaust steam from the high-pressure portion, that is, the temperature of the extraction steam, or the temperature of the exhaust steam from the low-pressure portion rises extremely. However, there is a problem that the rotor cannot be aligned with the increased temperature, and the rotor is misaligned, resulting in a large vibration of the rotor.

An object of the present invention is, in a bleed steam turbine, an exhaust steam from a high pressure portion upstream of a bleed air control valve of the turbine and an exhaust steam from a low pressure portion downstream of a bleed air control valve in a low load operation after the load is cut off. It is an object of the present invention to provide a temperature control device for an extraction steam turbine that can control the temperature of each of the above to a predetermined temperature that does not cause an abnormality in the turbine.

[0006]

According to the present invention, in order to solve the above-mentioned problems, a steam control valve provided at a turbine inlet and a bleed air control valve provided at a bleeding portion are provided, and a blade upstream of the bleed air control valve is provided. The temperature of the extraction steam turbine that controls the temperature of each exhaust steam from the high pressure part and the low pressure part during low load operation of the extraction steam turbine consisting of a high pressure part consisting of paragraphs and a low pressure part consisting of blades downstream from the extraction control valve. In the control device, the extraction temperature detector that detects the temperature of the exhaust vapor from the high pressure part, the exhaust temperature detector that detects the temperature of the exhaust vapor from the low pressure part, and the exhaust vapor from the high pressure part in the extraction temperature detector. The control means that controls the steam control valve from the deviation between the detected temperature of the exhaust gas and the target value of the predetermined temperature that does not cause abnormalities in the high pressure part, and the detected temperature of the exhaust steam from the low pressure part in the exhaust temperature detector and the abnormality in the low pressure part Cause Shall and control means for controlling the bleed control valve from the deviation between the target value of the predetermined temperature that does not.

[0007]

In the steam turbine, the temperature of the exhaust steam becomes higher as the flow rate of the steam flowing through the turbine becomes smaller, that is, as the load becomes lower, from the viewpoint of turbine efficiency. By the way, in a bleed steam turbine including a steam control valve provided at the turbine inlet and a bleed control valve provided at the bleed unit, the amount of steam flowing to the turbine is reduced during low-load operation, and therefore the high pressure upstream of the bleed control valve is increased. The temperature of each exhaust vapor in the low pressure portion downstream of the high pressure portion and the extraction control valve may increase, and may rise to a temperature that causes an abnormality in the high pressure portion and the low pressure portion.

Therefore, in order to prevent such a temperature rise, the temperature of the exhaust vapor from the high pressure portion in the extraction temperature detector is detected, and the detected temperature and a target of a predetermined temperature that does not cause abnormality in the high pressure portion are detected by the control means. The steam control valve is controlled based on the deviation from the value to control the amount of steam flowing into the high pressure section so that the temperature of the exhaust steam from the high pressure section reaches a predetermined temperature. On the other hand, the temperature of the exhaust vapor from the low pressure part is detected by the exhaust temperature detector, and the bleeding control valve is controlled by the control means from the deviation between this detected temperature and the target value of the predetermined temperature that does not cause abnormality in the low pressure part. The amount of steam flowing to the low pressure part is controlled to control the temperature of the exhaust steam from the low pressure part to a predetermined temperature.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a system diagram of an extraction steam turbine provided with a temperature control device. In FIG. 1, the extraction steam turbine 1 is provided with a steam control valve 6 at the turbine inlet and a extraction control valve 7 at the extraction section, and the turbine main body has a high pressure section 2 consisting of blade stages upstream of the extraction control valve 7 and an extraction valve. It is composed of a low pressure portion 3 composed of a blade downstream of the regulator valve 7. The condenser 5 is connected to the outlet of the low pressure section 3 via an exhaust pipe 4. Here, 8 is a main steam supply system that supplies steam to the turbine, 9 is an extraction steam supply system that extracts the exhaust steam from the high-pressure unit 2 and supplies it to the outside, and 10 is a main steam stop valve. A generator (not shown) is connected to the extraction steam turbine 1.

The governor 12 controls the rotational speed of the turbine, and is provided with a steam control valve controller 13 for controlling the steam control valve 6 and a bleed air control valve controller 14 for controlling the bleed air control valve 7. The extraction steam supply system 9 includes an extraction temperature detector 16 that detects the temperature of extraction steam extracted from the exhaust steam from the high-pressure unit 2, and the exhaust pipe 4 detects the temperature of exhaust steam from the low-pressure unit 3. An exhaust temperature detector 17 is provided. Reference numeral 18 is a main steam flow meter that indicates the flow rate of steam that flows into the turbine through the main steam supply system 8, and 19 is an extraction steam flow meter that indicates the flow rate of extraction steam that flows in the extraction steam supply system 9.

The extraction temperature controller 21 is an extraction temperature detector 16
A signal of the detected temperature of the extracted steam is input, and a deviation signal between the detected temperature and a target value of a predetermined temperature that does not adversely affect the strength and vibration of the high pressure part 2 of the turbine is output, and the governor 1
2 is input to the steam control valve controller 13. The exhaust temperature controller 22 outputs a deviation signal between the detected temperature of the exhaust steam from the low pressure part 3 in the exhaust temperature detector 17 and a target value of a predetermined temperature that does not adversely affect the strength and vibration of the low pressure part 3 of the turbine. Then, it is input to the extraction control valve controller 14 of the governor 12.

With such a configuration, in the extraction steam turbine 1, steam flows into the turbine through the main steam supply system 8 while the main steam stop valve 10 is open and the steam flow rate is controlled by the steam control valve 6. After expanding and working in the high-pressure part 2 and the low-pressure part 3, it flows into the condenser 5 to be condensed. At this time, the pressure of the extracted steam flowing through the extracted steam supply system 9 is controlled by the control of the extraction control valve 7, and the pressure thereof is supplied to the outside.
As described above, electric power is extracted from the generator according to the flow rate of the steam flowing through the high pressure portion 2 and the low pressure portion 3 and supplied to the electric power system.

However, the generator driven by the extraction steam turbine 1 may be cut off from the power system, that is, the load may be cut off. In this case, the generator driven by the extraction steam turbine 1 after the load is cut off is operated in parallel with the power system, and the extraction steam turbine 1 is operated at a low load.
At this time, the temperature control of the extraction steam turbine according to the present invention is performed, the steam control valve 6 and the extraction control valve 7 are controlled as described below, and the temperature of the exhaust steam from the high pressure portion 2, that is, the temperature of the extraction steam and the low pressure portion 3 are controlled. The temperature of the exhaust vapor from is controlled.

During a low load operation after the load of the extraction steam turbine 1 is cut off, the exhaust steam from the high pressure portion 2 detected by the extraction temperature detector 16, that is, the temperature signal of the extraction steam is input to the extraction temperature controller 21. A deviation signal between the detected temperature of the extracted steam and the target value of the predetermined temperature is output. Then, this deviation signal is input to the steam control valve controller 13 of the governor 12, and the opening of the steam control valve 6 is controlled so that this deviation becomes zero. At this time, the opening degree of the steam control valve 6 is in the opening direction when the temperature detected by the extraction temperature detector 16 is higher than the target value, and conversely when it is low, the closing direction.

On the other hand, a signal of the detected temperature of the exhaust vapor from the low pressure portion 3 in the exhaust temperature detector 17 is input to the exhaust temperature controller 22 and a deviation signal between the detected temperature of the exhaust vapor and the target value of the predetermined temperature. Is output. The deviation signal is input to the extraction control valve 14 of the governor 12, and the opening of the extraction control valve 7 is controlled so that the deviation becomes zero. At this time, the opening degree of the extraction control valve 7 is in the opening direction when the temperature detected by the exhaust gas temperature detector 17 is higher than the target value, and is in the closing direction when it is lower than the target value, as described above.

In this way, during the low load operation after the load is cut off, the temperature of the exhaust steam from the high pressure section 2 is controlled by the control of the steam control valve 6 so as not to adversely affect the strength and vibration of the high pressure section 2 of the turbine. Temperature control, while bleeding regulator 7
The exhaust steam from the low pressure portion 3 is controlled to a predetermined temperature that does not adversely affect the strength and vibration of the low pressure portion 3 of the turbine.

[0017]

As is apparent from the above description, according to the present invention, the temperature of each exhaust steam from the high pressure section and the low pressure section is controlled by the above-described structure during the low load operation after the load removal of the extraction steam turbine. By controlling the steam control valve and the bleed control valve, respectively, the temperature is controlled to a predetermined temperature that does not cause abnormalities in the high pressure part and the low pressure part of the turbine, so the strength of the turbine is maintained against temperature, and the vibration of the turbine is increased. Can be prevented.

[Brief description of drawings]

FIG. 1 is a system diagram of an extraction steam turbine including a temperature control device according to an embodiment of the present invention.

[Explanation of symbols]

 1 Extraction Steam Turbine 2 High Pressure Section 3 Low Pressure Section 6 Steam Control Valve 7 Extraction Control Valve 13 Steam Control Valve Controller 14 Extraction Control Valve Controller 16 Extraction Temperature Detector 17 Exhaust Temperature Detector 21 Extraction Temperature Controller 22 Exhaust Temperature Controller

Claims (1)

[Claims] 1. A steam control valve provided at a turbine inlet and a bleeding control valve provided at a bleeding section, and a high pressure section composed of a blade upstream of the bleeding control valve and a low pressure composed of a blade downstream of the bleeding control valve. The temperature control device for the extraction steam turbine that controls the temperature of each exhaust steam from the high pressure part and the low pressure part during low load operation of the extraction steam turbine consisting of A detector, an exhaust temperature detector that detects the temperature of the exhaust vapor from the low pressure part, and a target value of the detected temperature of the exhaust vapor from the high pressure part in the extraction temperature detector and a predetermined temperature that does not cause abnormalities in the high pressure part. Control means for controlling the steam control valve based on the deviation of the bleeding control valve, and the bleeding control valve for controlling the bleeding control valve based on the deviation between the detected temperature of the exhaust steam from the low pressure part in the exhaust temperature detector and the target value of the predetermined temperature that does not cause abnormalities in the low pressure part. Do Temperature control apparatus of the extracted steam turbine, characterized in that a control means.