JPS6231163B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is applicable to cases where a sudden accident occurs in a factory that utilizes extracted air from an extraction turbine, and it becomes necessary to temporarily suddenly reduce the supply of extracted air to the factory. The present invention also relates to a method for controlling the operation of an extraction turbine, which enables safe operation of the boiler and turbine without changing the amount of high-pressure steam.

FIG. 1 shows a system diagram of an example of a conventional extraction turbine operation control method, in which 1 is a high-pressure turbine, 2 is a low-pressure turbine, 3 is a condenser, and 4
is a generator, 5 is a high-pressure steam control valve, 6 is a low-pressure steam control valve, 7 is an extraction line leading to the factory side, 8 is a speed governor of the turbine shaft system, and the synchronized speed machine 8 is a regulator of the rotation speed n of the turbine shaft. The change in the governor primary control signal P ₁ , which is proportional to the square, is magnified and converted into the governor control signal P ₂ , and the governor control secondary signal P ₂ (hereinafter, the governor control secondary signal is simply referred to as the governor control signal P 2). The signal P ₂ is used to operate the high pressure steam regulating valve 5 in the opening or closing direction via the speed control signal line 9, and the low pressure steam regulating valve 6 is simultaneously operated in the opening or closing direction with the high pressure steam regulating valve 5. They are designed to operate in the same direction.

Therefore, when the speed governor control signal _P2 changes, the high pressure steam control valve 5 and the low pressure steam control valve 6 operate in the same direction, opening and closing, and the resulting change in steam amount is approximately the same amount. This allows the turbine output to be increased or decreased without changing the amount of extracted air.

Next, 10 is a bleed air pressure control device connected to the bleed air line 7, and 11 is a bleed air pressure control signal air pressure P from the bleed air pressure control device 10 in order to control the bleed air pressure to be constant according to changes in the bleed air pressure. control air signal line of _a (hereinafter the bleed pressure control signal air pressure P _a is simply referred to as the bleed control air signal P _a ), 12
13 is a converter that converts the bleed control air signal P _a into a bleed control signal P _A that operates the high pressure steam control valve 5;
is a bleed air control signal P _A line, 14 is a converter that converts the bleed air control air signal P _a into a bleed air control signal P _B that operates the low pressure steam control valve 6, and 15 is a bleed air control signal P _B line; When the bleed air pressure changes, the bleed air control air signal P _a from the bleed air pressure control device 10 changes, and in response, the bleed air control signal P _A issued from the converter 12 also changes, but the bleed air control signal P _A changes depending on the bleed air pressure. If it rises, high pressure steam control valve 5
is operated in the closing direction, and when the bleed air pressure decreases, it is operated in the opening direction. At the same time, the change in the bleed air control air signal P _a is caused by the bleed air control signal P _B issued via the converter 14.
The bleed air control signal P _B operates the low pressure steam control valve 6 in the opening direction when the bleed air pressure increases, and in the closing direction when the bleed air pressure decreases. In other words, the high-pressure steam control valve 5 and the low-pressure steam control valve 6 operate in opposite directions to open and close in response to changes in the bleed pressure, thereby maintaining the bleed steam while keeping the turbine output almost constant. The plan is to control the bleed pressure almost constant as the amount increases or decreases.

During normal operation, high-pressure steam introduced into the high-pressure turbine 1 from a boiler (not shown) via the high-pressure steam control valve 5 becomes low pressure by operating the high-pressure turbine 1, and a part of the low-pressure steam is extracted from the Air is extracted through line 7 and sent to the factory side, for example a paper machine line in a paper mill, where it is used as a heat source. Further, the remaining low-pressure steam is introduced into the low-pressure turbine 2, and after operating the low-pressure turbine 2, is led to the condenser 3. The power generation system of the generator 4 is normally connected to the power purchasing system of the power company outside the factory (hereinafter, this will be referred to as generator parallel operation).

Therefore, since the rotational speed is synchronized with the power purchasing system, the speed control signal _P2 remains at a nearly constant value unless operated by the operator, and the amount of power generated by the generator 4 changes depending on the increase or decrease in the output of the turbine. It also increases and decreases.

Next, the extracted steam is used when the generator 4 is operated in parallel using the conventional operation control method. For example, a case will be explained in which an accident such as a paper cut in the paper machine suddenly occurs on the paper machine line of a paper manufacturing factory. Since the amount of bleed steam used in the paper machine line due to the sudden accident suddenly decreases, the amount of bleed steam supplied from the turbine also sharply decreases at the same time. Therefore, the bleed pressure in the bleed line 7 suddenly rises, and the bleed control signal P _A sent by the bleed pressure control device 10 via the converter 12 causes the high pressure steam control valve 5 to close, and the converter 14 The bleed control signal P _B transmitted through the bleed air control signal P B respectively operates the low pressure steam control valve 6 in the opening direction. When the amount of extracted steam from the turbine decreases by the same amount as the reduced amount of extracted steam used by the factory, the extracted air pressure control device 10 sends an air extraction control signal P _A /
High pressure steam control valve 5 and low pressure steam control valve 6 by P _B
The closing/opening operation of is stationary. In this case, as a matter of course, the high-pressure steam control valve 5 is operated in the closing direction and becomes stationary by the extraction control signal _PA , so that the amount of high-pressure steam supplied to the high-pressure turbine 1 is also rapidly reduced. , it is practically impossible to immediately reduce the amount of boiler evaporation. This caused problems such as the boiler's high-pressure safety valve operating and steam blowing out. Such an accident in which the amount of bleed steam suddenly decreases in the bleed line 7, for example due to a paper cut in a paper machine, usually occurs several times or more every day.

The horizontal axis of the turbine performance curve shown in FIG. 3 is the turbine output N _G , the intersection of the horizontal axis and the vertical axis is zero output, and the right side is the increasing output side. The vertical axis is the high pressure steam amount G _H of the high pressure turbine 1, the intersection of the vertical axis and the horizontal axis is zero high pressure steam amount, and the upper side is the increasing side of the high pressure steam amount. The maximum turbine output in Figure 3 is the line between A and B, and the turbine output becomes zero at C.
The line between ~D and the maximum amount of high pressure steam is F~
It is A line. The relationship between the amount of extracted steam and the amount of high pressure steam G _H is, for example, the line of zero extracted steam amount G _e0 is C ~
B, and when the extracted steam amount is constant G _e1 , K ₁ ~
A ₁ line, and the extracted steam amount is G _e2 and G
After increasing to _e3 , G _e4 , G _e5 , the relationships between the turbine output N _G and the high pressure steam amount G _H when held constant are K ₂ ~ _{A 2} , K ₃ ~ A ₃ , K _A ~ A, and E, respectively. It is indicated by the line between ~F. The amount of low pressure steam to the low pressure turbine is approximately equal to the amount of steam obtained by subtracting the amount of extracted steam G _e from the amount of high pressure steam G _H to the high pressure turbine 1 . The low-pressure steam amount G _L to the low-pressure turbine 2 is the same on the lines indicated by D ~ E, F ₀ ~ F, and A ₀ ~ A, and the low pressure steam amount _GL intersects with the C ~ B line. High pressure turbine 1 equivalent to D ₀ point, F ₀ point, A ₀ point
It is almost the same as the amount of high-pressure steam _GH . The minimum point of the low pressure steam amount G _L is a line connecting D ~ K ₁ ~ _{K 2} ~ K ₃ ~ K _A ~ E, which prevents overheating of the low pressure turbine 2 and allows the minimum cooling steam of the low pressure turbine 2 to flow. This means that the low pressure steam control valve 6 is completely closed. This is how the turbine performance curve is drawn.

FIG. 4 is a characteristic curve of a servo motor for operating the high pressure steam control valve 5. The horizontal axis is the speed governor control signal P ₂
, and the servo motor lift l _H for high pressure steam control valve 5 is taken on the vertical axis. The bleed control signal P _A that operates the servo motor for the high pressure steam control valve 5 is P _A
0 , P _A1 , P _A2 , P _A3 , P _A4 , P _A5 are constant, and the operating line when the governor control signal P ₂ changes is c.
〜b, _k1〜a1 , _{k2〜a2 , k3〜a3 , kA〜a} , _e〜
Indicated by f. When the governor control signal P ₂ is constant and the bleed control signal _PA changes, the servo motor lift for the high pressure steam control valve 5 operates parallel to the vertical axis. Note that A, A 3 , A ₂ , A 3 , A ₂ ,
A ₁ , B, A ₀ , F ₀ , C, D ₀ , D, K ₁ , K ₂ , K ₃ , K
Each point _A , E, F is the high pressure steam control valve 5 in Fig. 4.
a, a ₃ , a ₂ , a ₁ , on the servo motor characteristic curve for
b, a ₀ , f ₀ , c, d ₀ , d, k ₁ , k ₂ , k ₃ , k _A , e,
Point f is the corresponding point. For example, the servo motor lift l _H for the high pressure steam regulator 5 when operating at point A on the turbine performance curve in Figure 3 is the point a on the servo motor characteristic curve for the high pressure steam regulator 5 in Figure 4. To maintain this point a, the servo motor lift _lH for the high pressure steam control valve 5 at point a is maintained by the speed governor control signal _P2 and the bleed control signal P _A3 .

FIG. 5 shows a servo motor characteristic curve for operating the low pressure steam control valve 6. The horizontal axis is the speed governor control signal P ₂
, and the servo motor lift l _L for the low pressure steam control valve 6 is taken on the vertical axis. The bleed control signal P _B that operates the servo motor for the low pressure steam control valve 6 is P _B
0 , P _B1 , P _B2 , P _B3 , P _B4 , P _B5 are constant, and the operating line when the governor control signal P ₂ changes is c'~
b′, k ₁ ′ ~ a ₁ ′, k ₂ ′ ~ a ₂ ′, k ₃ ′ ~ a ₃ ′, k ₄ ′ ~ a′
, e′~
Denoted by f′. The operating line when the other bleed control signal P _B is constant is on a line substantially parallel to the c'-b' line. When the governor control signal P ₂ is constant and the bleed control signal P _B changes, the servo motor lift for the low pressure steam control valve 6 operates parallel to the vertical axis. In addition, A, A ₃ , A ₂ , A ₁ , B, A ₀ , F ₀ ,
As mentioned above, each point C, D ₀ , D, K ₁ , K ₂ , K ₃ , K _A , E, F is a, a ₃ on the servo motor characteristic curve for the high pressure steam regulator 5 in Fig. 4. , a ₂ , a ₁ , b,
The points a ₀ , f ₀ , c, d ₀ , d, k ₁ , k ₂ , k ₃ , k _A , e, and f correspond to each other, and at the same time, the servo motor for the low pressure steam control valve 6 in FIG. a′, a ₃ ′, on the characteristic curve
a ₂ ′, a ₁ ′, b′, a ₀ ′, f ₀ ′, c′, d ₀ ′, d′, k ₁ ′
,k ₂ ′,
It is also the point where k ₃ ′, k _A ′, e′, and f′ points correspond. In addition, the speed governor control signal _P2 value at each corresponding point is the high pressure steam control valve 5.
Both the servo motor for the low pressure steam control valve 6 and the low pressure steam control valve 6 have the same speed regulating control signal _P2 value. For example, when the turbine is operating at point A on the turbine performance curve in FIG. 3, it is at point a on the servo motor characteristic curve for high pressure steam regulator 5 in FIG. It is point a' on the servo motor characteristic curve, the bleed control signal values are P _A0 and P _B0 values, and the governor control signal P ₂
The value is the same _P2 control signal value for both the high pressure steam control valve 5 and the low pressure steam control valve 6.

FIG. 6 is a bleed control signal P _A /P _B characteristic curve of the bleed pressure control device 10. The horizontal axis shows the bleed steam pressure (P bleed) or the bleed control primary signal P bleed ₁ which changes according to the change in the bleed pressure, and the vertical axis shows the bleed control signal value P _A /P _B. If the bleed control primary signal (P _bleed1 ) changes due to bleed pressure (P bleed) or bleed air fluctuations, the P _A /P _B values will also change from P _A0 and P _B0 to P
If _the amount _of extracted _{steam changes} further to _{A1 and} P _B1 , _{the extracted steam pressure (} P bleed) or the same bleed control primary signal value on the P _A characteristic line and the P _B characteristic line, respectively. These points correspond to the turbine performance curve shown in Figure 3 above, the servo motor characteristic curve for high pressure steam control valve 5 shown in Figure 4, and the servo motor characteristic curve shown in Figure 5.
This corresponds to the servo motor characteristic curve for the low-pressure steam control valve 6 shown in the figure and the bleed control P _A /P _B characteristic curve shown in FIG.

Each point on the turbine performance curve in Figure 3, each point on the servo motor characteristic curve for high pressure steam regulator 5 in Figure 4, and each point on the servo motor characteristic curve for low pressure steam regulator 6 in Figure 5. The corresponding points of each are as described above. The bleed control signal P _A /P _B values in FIG. 6 also have the same signal symbol corresponding to the constant bleed steam amount line of each characteristic curve. That is, G _e0 , G _e1 , G _e2 , G _e3 , _{G e} shown in the constant extracted steam amount line of the turbine performance curve in FIG.
₄ , G _e5 correspond to P _A0 , P _A1 , P _A2 , P _A3 , P A4 , P _A5 shown on the constant extraction steam amount line of the servo motor characteristic curve for high pressure steam control valve ₅ in Fig. 4. At the same time, P _B0 , P _B1 , P _B2 , P _B3 , P _B4 , P _B5 shown in the constant extraction steam amount line of the servo motor characteristic curve for the low pressure steam control valve 6 in FIG. 5 correspond. P _A0 , P _A1 , P _A of the bleed air control signal P _A /P _B values in each of the characteristic curves in FIGS. 4 and 5
₂ , P _A3 , P _A4 , P _A5 and P _B0 , P _B1 , P _B2 ,
P _B3 , P _B4 , P _B5 are the bleed air control signals P _A /
Each corresponds to the same control signal symbol in the P _B characteristic curve.

In the conventional operation control method, the turbine performance curve in FIG. 3 and the turbine performance curve in FIG.
The servo motor characteristic curve for high pressure steam control valve 5 shown in the figure,
This will be explained with reference to the servo motor characteristic curve for the low pressure steam control valve 6 shown in FIG. 5 and the bleed control signal P _A /P _B characteristic curve shown in FIG. For example, when operating at point M as shown in Figure 3, if the amount of extracted steam suddenly decreases from G _e3 to G _e1 , the turbine operating point will be either point M or S in the figure.
Move from point M to point S, which has the same symbol in both Figures 4 and 5, as indicated by the arrow ``A'', and in Figure 6 move from point ``A'' to point ``A''. At this time, the bleed air control signal P _A moves from the M _A point to the S _A point, and the signal P _A changes from the P _A3 value to the P _A1 value, and the bleed air control signal P _B becomes M _{B The signal P B changes} from the P _B3 value to the P _B1 value. As a result of such control operations, as shown in the turbine performance curve in Figure 3, the turbine output remains almost constant at N _M ≒ N _S , and the amount of extracted steam rapidly decreases from the G _e3 value to the G _e1 value. However, as a result, the amount of steam flowing to the high-pressure turbine 1 rapidly decreases, and the low-pressure turbine 2
The amount of steam flowing into the area increases rapidly. In this case, the sudden increase in the amount of steam to the low-pressure turbine 2 is a sudden increase in the displacement of the low-pressure turbine 2, and there is no problem because the steam is sent to the condenser 3, but as described above, the amount of steam to the high-pressure turbine 1 is Sudden reductions cannot immediately reduce the amount of evaporation in the boiler, so conventional methods have had the disadvantage of causing problems such as activation of the boiler's high-pressure safety valve.

The present invention solves the problems of the conventional extraction turbine operation control method described above, and when the generator 4 is operating in parallel, a sudden accident occurs in the extraction steam utilization system of the factory, and the extraction steam is not supplied to the factory. The purpose of this proposed method is to provide an extraction turbine operation control method that enables stable operation with a constant boiler evaporation amount and a constant steam amount to the high-pressure turbine when it is necessary to rapidly reduce the supply amount. This means that the bleed control signal P _A , which controls the opening degree of the high-pressure steam control valve from the bleed pressure control device, is temporarily reduced to the point immediately before the sudden drop in the amount of bleed steam by the means activated by the sudden decrease signal of the amount of bleed steam on the factory side. This bleed control signal P
_A and a substantially constant speed governor signal _P2 from a speed governor of the turbine shaft system to control the opening degree of the high pressure regulating valve,
The opening degree of the low-pressure steam regulating valve is controlled by the bleed control signal P _B which controls the opening degree from the bleed pressure control device and the speed regulating control signal P ₂ having a substantially constant value. This invention relates to an operation control method for an extraction turbine, characterized in that an extraction control operation is performed with a constant amount of high-pressure steam when the usage state of the turbine suddenly decreases.

Hereinafter, a system diagram of an example of the extraction turbine operation control method of the present invention is shown in FIG. 2, and in the same figure,
1 is a high-pressure turbine, 2 is a low-pressure turbine, 3 is a condenser, 4 is a generator, 5 is a high-pressure steam control valve, 6 is a low-pressure steam control valve, 7 is an extraction line, 8 is a speed governor, 9 is a speed governor Control signal P ₂ line, 10 is a bleed pressure control device, 11 is a bleed control air signal P _a line, 12 is a converter for the bleed control signal P _A (details will be explained in FIG. 7), 13 is a bleed control signal P _A line, 14 is a converter for the bleed air control signal P _B , and 15 is the bleed air control signal P _B line. The above-mentioned parts (symbols 1 to 15) other than the connecting part _a are almost the same as those in the conventional method shown in FIG. 1 above. 21 is a solenoid valve for the bleed control air signal P _a and P _aa line which is activated and fully closed when the bleed air amount suddenly decreases, and is fully opened when the bleed air amount is restored;
22 is the bleed control air signal P _aa line to the converter 12 for the bleed control signal P _A , and the bleed control signal line 22 becomes a closed room state when the solenoid valve 21 is fully closed, and the bleed control air signal line 22 is connected to the bleed control air signal P aa line which is connected to the converter 12 for the bleed air control signal P A. The P _aa value of the signal is maintained. When the solenoid valve 21 is fully opened, the P _aa signal value becomes the same as the P _a signal value. 23 is the sudden accident signal line where the amount of extracted steam used in the factory suddenly decreases, 2
4 is a command unit for opening and closing the solenoid valve 21, 25 is a command transmission line, and 26 is restored after the bleed air volume sudden decrease accident occurs, and the bleed air control air signal P _a is changed to the value of the bleed air control air signal P _aa immediately before the accident occurred. 27 is a differential pressure transmitter 26, which is a type of differential pressure transmitter that detects when it has almost recovered.
This is the return signal line from.

With reference to the system diagram shown in FIG. 2, normal air extraction operation control when the generators 4 are operated in parallel will be explained. First, when the output of the turbine is increased or decreased in order to rapidly reduce the amount of power generated by the generator 4, when the driver operates the speed governor 8, the speed governor control signal _P2 changes, and high pressure steam is sent via the speed governor signal line 9. The control valve 5 and the low pressure steam control valve 6 operate in the same direction to open or close,
Since the amount of high-pressure steam and the amount of low-pressure steam are increased or decreased by approximately the same amount, the turbine output can be increased or decreased according to the operator's operation without changing the amount of extracted steam. If the amount of increase or decrease in the amount of high-pressure steam and the amount of low-pressure steam is not the same and there is a slight difference, the amount of extracted steam will change, so the extraction pressure control device 1
By operating 0, the amount of extracted steam is maintained at the level used by the factory. Next, when the factory bleed air amount in the bleed line 7 changes, the bleed pressure control device 10 operates and the bleed control air signal P _a changes, and the solenoid valve 21 is fully open during normal bleed control operation, so the bleed air is controlled. The air signal P _a has the same value as the bleed air control signal P _aa , and the bleed air control signal P _aa changes. In response to this, the bleed control signal P _A also changes, and if the bleed pressure increases, the high pressure steam control valve 5 is operated in the closing direction, and if the bleed pressure decreases, the high pressure steam control valve 5 is operated in the open direction. At the same time, the bleed air control air signal P _a
The change in bleed air control signal P _B generated via the converter 14 also changes, and when the bleed air pressure increases via the bleed air control signal P _B line 15, the low pressure steam control valve 6 opens, and when the bleed air pressure decreases, the bleed air control signal P B changes. By opening and closing in the opposite direction to the high pressure steam control valve 5 in the closing direction, the extraction pressure is controlled to be approximately constant in accordance with the increase or decrease in the amount of extracted steam while keeping the turbine output approximately constant. These normal operation controls are the same as conventional operation control methods.

Next, the case of operation control when the amount of extracted steam suddenly decreases when the generator 4 is operated in parallel will be explained with reference to the system diagram shown in FIG. 2 according to the present invention. For example, if an unexpected accident such as a paper break in a paper machine occurs and the amount of extracted steam supplied from the turbine suddenly decreases, in the same figure, the accident occurrence signal 23 issued from the factory side will be sent to the command unit. 24, the command is immediately transmitted to the solenoid valve 2 via the command transmission line 25.
1 is fully closed, and the converter 12 for the bleed air control signal P _A
Since the bleed air control signal P _aa line connected to the bleed air control air signal P aa line is closed, the bleed air control air signal P _aa value maintains the same constant value as the value immediately before the accident, and this bleed air control air signal P _aa signal connects the converter 12. The bleed air control signal P _A
is generated, the bleed air control signal P _A value also remains stationary while maintaining the P _A value immediately before the accident occurred, and the speed governor control signal P ₂ is an almost constant value since the generator 4 is operated in parallel. The high-pressure steam control valve 5 remains stationary while maintaining the opening degree immediately before the accident occurred. On the other hand, the value of the bleed air control signal P _B that operates the servo motor of the low pressure steam control valve 6 changes as the bleed air control air signal P _a changes as the steam pressure in the bleed line 7 rises, and is applied via the converter 14. This P _B value causes the low pressure steam control valve 6 to operate in the opening direction, and the amount of steam to the low pressure turbine 2 increases.

Therefore, the amount of extracted steam to the factory side decreases, and the operation of the low-pressure steam control valve 6 is stopped when the amount of extracted steam becomes approximately the same amount as the rapidly decreased amount of steam. In this way, in the event of the sudden accident, the high pressure turbine 1
It is possible to cope with a sudden decrease in the amount of extracted steam by keeping the amount of steam constant. At this time, the amount of steam to the low-pressure steam turbine 2 increases, so the turbine output also increases, and the amount of power generated by the generator 4 also increases, but if the amount of power used at the factory does not change, the power will not be transmitted to the factory from an external power company. The amount of purchased electricity will be reduced by the increase in the amount of power generated by the generator 4. However, problems such as high-pressure steam blowing out from the boiler's high-pressure safety valve can be resolved.

Next, when the sudden accident that caused the sudden decrease in the amount of extracted steam is resolved and the amount of extracted steam is restored to the factory side, the steam pressure in the extracted steam line 7 will also drop, and accordingly, the extracted steam control device 10 will release the extracted steam. Signal P _a
The value also returned to the value before the accident, and the bleed air control air signal P
When _{the a} value becomes the same as the bleed control air signal P _aa value, which is the value before the sudden accident and is stationary, a repeat signal is issued from the differential pressure gauge 26 to inform that the pressure has returned to the same pressure, and in response to this, the command is issued. A signal for opening the solenoid valve 20 is issued from the section 24 via the command transmission line 25. In this way, the turbine bleed control operation returns to the state before the sudden accident and returns to normal control operation.

The system diagram shown in FIG. 7 is an example showing the components of a converter (converter 12 in FIG. 2) that converts the bleed control air signal P _aa into the bleed control signal P _A. The bleed air control signal P _A line, 22 indicates the bleed air control air signal P _aa line, and these 1
3 and 22 are the same as those in the system diagram in Figure 2,
31 is a bellows receiving the control air signal P _aa ; 32
33 is the valve _seat of the cup valve 32, 34 is the orifice, 35 is the fulcrum, 36 is the leaf spring, 37 is the lever on which the lever acts, and 38 is the cup valve that generates the bleed control signal P _A. A spring for adjusting the set value, and 39 are high-pressure oil supply piping to the bleed air control signal P _A. Hose balance type air pressure/
It is a hydraulic conversion device. For example, when the control air signal P _aa changes to the high pressure side, the force that pushes the lever 37 of the bellows 31 changes, and the force applied to the lever 37 is applied to the spring 38 and bellows 31 from above, and the cup valve 32 from below. The balance is lost, and bellows 3
The downward force applied to the cup valve 32 by the lever 37 changes according to the principle of force balance, in which a change in force of 1 is a moment of force about the fulcrum 35 of the lever 37. The bleed air control signal P _A value also changes by an amount corresponding to this change in force.
Changes in this control air signal P _aa and bleed air control signal P _A
The change in is almost linearly inversely proportional. The converter 14 for the bleed control signal P _B shown in the system diagram of FIG. 2 has the bellows 31 shown in FIG. It is almost the same as the converter for the signal P _A , and the changes in the control air signal P _a and the bleed air control signal P _B have an almost linear proportional relationship, and each of these characteristics corresponds to the bleed air control signal P shown in FIG. It is the same as _{the A} /P _B characteristic curve.

When the generator 4 is operated in parallel, the operation control method according to the present invention is applied based on the turbine performance curve shown in FIG. 3 and the high-pressure steam regulator servo motor characteristic shown in FIG. 4. This will be explained with reference to the low pressure steam control valve servo motor characteristic curve shown in FIG. 5, and the bleed control signal P _A /P _B characteristic curve shown in FIG. For example, as shown in Figure 3, M
When operating at a point, the amount of extracted steam changes from G _e3 to G _e1
When the turbine operating point suddenly decreases, the turbine operating point moves from point M to point K in the same figure, as shown by the arrow "B", and in Figure 4 it stays at point K, which is almost the same position as point M, and in Figure 5 it moves from point M to point K. The bleed air control signal P _A stays at the M K point which is almost the same as the M _A point in _Fig . 6, and the signal P _A is almost the same as the P _A3 value. _{The AK} value is held, and the bleed control signal P _B moves from point M _B to point K _B in the direction of the "ro" arrow, and the signal value P _B changes from the P _B3 value to the P _BK value. Through such control operations, as shown in the turbine performance curve in Figure 3, the turbine output moves from N _M to N _K , but the high-pressure turbine inlet steam amount remains at the G _HK value, which is approximately the same as the G _HM value. While being maintained at a substantially constant value, the extracted steam amount rapidly decreases from the G _e3 value to the G _e1 value and comes to a standstill. As a result, the amount of steam flowing to the low-pressure turbine 2 increases rapidly by an amount corresponding to the sudden decrease in the amount of extracted steam.
Since the amount of steam to the high-pressure turbine 1 is constant, problems such as activation of the high-pressure safety valve of the boiler do not occur.

Next, when the sudden accident that suddenly reduced the amount of extracted steam is resolved and the amount of extracted steam is restored to the factory, it is restored by the reverse control operation at the time of the sudden accident. In Figure 3, it returns from point K to point R, which is approximately the same position as point M, as shown by the arrow "C"; in Figure 4, it returns while staying at point R, which is approximately the same position as point M; and in Figure 5, it returns to point R, which is approximately the same position as point M. Then from point K to R
In Fig. 6, the bleed air control signal P _A returns from the M _K point to the R _A point, which is approximately the same position as the M _A point, and the bleed air control signal P _B changes from the K _B point to the M _B point. Returns to point _RB , which is almost the same as . In this way, if the air bleed control operation returns to the state before the sudden accident, the normal air bleed operation control method will be used.

As described above, since the operation control method of the present invention has the above-described structure and operation, according to the present invention, if a sudden accident occurs in a factory that uses extracted steam, Even if the amount of bleed air supplied to the boiler suddenly decreases, the bleed operation can be controlled to maintain a constant amount of main steam, which has the practical effect of eliminating problems such as the boiler's safety valve blowing.

In addition, although the control signal system described in the embodiment is of a hydraulic type, the present invention is not limited to such an embodiment, and may include an electric type, etc., within the scope of the spirit of the present invention. It goes without saying that the invention can be applied to various control devices and can be modified in various ways.

[Brief explanation of the drawing]

FIG. 1 is a system diagram showing an example of a conventional method.
FIG. 2 is a system diagram of one embodiment of the present invention. 3 is a turbine performance curve diagram, FIG. 4 is a servo motor characteristic curve diagram for high pressure steam regulator 5, FIG. 5 is a servo motor characteristic curve diagram for low pressure steam regulator 6,
FIG. 6 shows the bleed control signal P of the bleed pressure control device 10.
It is an _A / _PB characteristic curve diagram. FIG. 7 shows P _aa /P _A which converts the bleed air control air signal P _aa into the bleed air control signal P _A
It is a system diagram of a converter. 1: high pressure turbine, 2: low pressure turbine, 3: condenser, 4: generator, 5: high pressure steam control valve, 6: low pressure steam control valve, 7: extraction line, 8: speed governor of turbine shaft system, 9: Speed governor control signal P ₂ lines, 10:
Bleed air pressure control device, 11: Control air signal P _a line, 12: Control air pressure/control oil pressure P _A converter,
13: Bleed air control signal P _A line, 14: Control air pressure/control oil pressure P _B converter, 15: Bleed air signal P _B line, 21: Solenoid valve, 22: Bleed air control signal P _aa line, 23: Sudden accident occurrence signal line, 24: command unit, 25: command transmission line, 26: a type of differential pressure transmitter, 27: return signal line, 31: bellows, 32: cup valve, 33: valve seat of cup valve, 3
4: Orifice, 35: Fulcrum, 36: Leaf spring, 3
7: Lever that acts as a lever, 38: Spring that adjusts the set value of the bleed air control signal P _A , 39: High pressure oil supply pipe to the bleed air control signal P _A.

Claims (1)

[Claims] 1 In the extraction turbine which controls the extraction steam pressure sent to the factory side by the high pressure steam control valve and the low pressure steam adjustment valve, it is activated by this sudden decrease signal when the usage status of the extraction steam on the factory side suddenly decreases. The means temporarily maintains the bleed control signal P _A from the bleed pressure control device, which controls the opening degree of the high-pressure steam control valve, at the signal value immediately before the sudden decrease, and adjusts the bleed control signal P _A and the turbine shaft system. The opening degree of the high pressure regulating valve is controlled by a substantially constant speed regulating signal _P2 from the speed generator, and the opening degree of the low pressure steam regulating valve is controlled by the opening degree from the bleed pressure control device. Signal P
_B and the above-mentioned speed governor control signal _P2 having a substantially constant value, it is possible to perform extraction operation control with a constant amount of high-pressure steam when the use of the above-mentioned extracted steam on the factory side suddenly decreases. Characteristics of the extraction turbine operation control method.