JPH04203401A - Turbine control device - Google Patents

Abstract

PURPOSE:To stabilize an electric power system by making the control width of a variable according to the value opening set value of a value opening setter. CONSTITUTION:When a value opening set value P1 is large in a condition in which a turbine/power generator is operated in synchronization with an electric power system, multiplier value K2 outputted from a function generator 6 is increased and the output value P2 of multiplier 4 is enlarged with respect to a speed deviation signal S3, thereby, turbine speed is controlled positively. On the other hand, when the value opening set value P1 is small, a steam amount generating from a boiler is reduced, and the multiplier value K2 is reduced since a boiler side comes in an unstable operation range so as to reduce change amount of the steam amount with respect to the speed change of the burbine, thereby, the turbine speed is in a range in which operation is possible. On the other hand, when the load of the burbine/power generator is shut out, the turbine speed is controlled in order to prevent any overspeed of the turbine. It is thus possible to stabilize the electric power system.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a turbine control device that can contribute to stabilizing the output of a turbine/generator.

(Prior Art) The power generating equipment in a turbine/generator of a thermal power plant has a configuration as schematically shown in FIG. 5. In FIG. 5, the turbine 17 is driven by the steam generated in the boiler 15 flowing through the steam control valve 16.
The steam that has entered the turbine 17 is exhausted to the condenser 18. A generator 19 is directly connected to the turbine 17, and as the generator is rotated by the turbine 17, a power generation output is obtained. This generator 19 is connected to an electric power system 21 via a breaker 2o for synchronous operation.

By the way, in such a turbine/generator, in order to control the output of the generator 19, the boiler 15 is connected to the turbine 1.
This is done by adjusting the opening degree of the steam control valve 16 wJ to control the amount of steam flowing into the steam control valve 7.

FIG. 6 is a circuit diagram showing an example of the configuration of such a conventional turbine control device. As shown in FIG. 6, the actual turbine speed signal S2 detected by the speed detector 2 and the turbine reference speed set in the reference speed setter 1, that is, the rated set speed S1 are input to the adder 3. The deviation between the two signals is determined, and this is given to the coefficient unit O as a speed deviation signal S. This coefficient multiplier 10 sets a speed control gain, which is generally called a speed adjustment rate, and is usually set at a rate of 4 to 5%, although it varies depending on the power system. Here, for example, an adjustment rate of 5% means a gain that changes the turbine output by 100% with a speed change (deviation) of 5%.

Also, the speed control signal P4 output from this coefficient unit 10
and the valve opening setting signal P output from the valve opening setting device 8 are input to the adder 9, and the added signal is given to the operator of the steam control valve 16 as the valve opening command signal P]. It is. In this case, the valve opening degree setting device 8 sets the valve opening degree of the steam control valve 16, and by setting this setting device 8, the operator obtains the required turbine output.

In a turbine control device with such a configuration, if an imbalance occurs between the generated power value and the demanded power (load power) in the power system, the power system frequency changes, so the turbine control system that is operating in synchronization with the power system changes. The speed of will also change. When the turbine speed changes, the speed change signal S3 input to the coefficient multiplier 10 changes, so it is obtained by adding the signal P4 multiplied by the coefficient in the coefficient multiplier 10 and the setting value of the valve opening setting device 8. The valve opening command signal P3 also changes. Therefore, by inputting this valve opening command signal P to the operator of the steam regulating valve 16, the valve opening of the steam regulating valve 16 is controlled so that the turbine speed is constant.

Here, the relationship between the turbine speed S2 and the valve opening command signal P is shown in FIG.

That is, the characteristics shown in FIG. 7 assume that the speed regulation rate set by the coefficient unit 10 is 5%, and the graph a shows the valve opening setting value P.
, is set to 100%, and the graph b is when Pl is kept constant at 50%.

In both graphs, when turbine speed S2 increases, valve opening command P3 decreases, and when S2 decreases, P
3 shows an increasing characteristic. Then, the reference speed S1
It can be seen that the rate of change in P3 with respect to is constant in all graphs.

(Problem to be Solved by the Invention) When the frequency of the power system, that is, the turbine speed changes in this way, it is essential for the power system to perform control to correct this change as described above. .

However, in a steam turbine power generation system such as in a thermal power plant, the fluctuation period is fast and the fluctuation range is relatively large in the turbine control system, so there is a generation output range in which the boiler side that generates steam cannot follow. There is. For example, if the turbine output, i.e. the amount of steam generated by the boiler, is small, the control of the flow rate of water fed to the boiler becomes unstable, and the fuel control of the boiler becomes unstable, so turbine speed control is excluded. There is a problem in that it is necessary to operate with the valve opening set value constant and the steam control valve 16 maintained at a constant opening, resulting in the inconvenience of not being able to contribute to frequency control of the power system.

The present invention provides a turbine control device that contributes to stable load operation of the power system by expanding the frequency control range of the power system, and that prevents the turbine from accelerating beyond a specified value even if the load on the turbine/generator is cut off. The purpose is to provide

[Configuration of the Invention (Means for Solving the Problems) In order to achieve the above object, the present invention configures the following turbine control device.

(1) The turbine is activated by a signal that is the sum of the turbine steam valve opening setting signal, which sets the reference value of the generated power of the turbine/generator that is operated in synchronization with the power grid, and the turbine speed and speed reference speed deviation signal. A turbine control device that controls the output of the turbine/generator by adjusting the opening degree of a steam control valve, a multiplier that receives the speed deviation signal and sets a speed control gain of the speed deviation signal; a function generator that receives a valve opening setting signal, generates a gain setting signal according to the magnitude of the turbine steam valve opening setting signal, and varies the speed control gain of the speed deviation signal that is input to the multiplier; It is equipped with the following.

(2) The turbine is activated by a signal that is the sum of the turbine steam valve opening setting signal, which sets the standard value of the generated power of the turbine/generator that is operated in synchronization with the power grid, and the turbine speed and the speed deviation signal based on the speed standard. A turbine control device that controls the output of the turbine/generator by adjusting the opening degree of a steam control valve, a multiplier that receives the speed deviation signal and sets a speed control gain of the speed deviation signal; a function generator that receives a valve opening setting signal and generates a gain setting signal according to the magnitude of the turbine steam valve opening setting signal; a signal generator that outputs a constant gain setting signal; When the turbine/generator is operating in synchronization with the power grid, the gain setting signal generated from the function generator is input to the multiplier, and the turbine/generator is operated in isolation from the state in which it is operating in synchronization with the power grid. and switching means that performs a switching operation to input the output signal of the signal generator to the multiplier when the signal generator is in the state.

(3) The turbine is activated by a signal that is the sum of the turbine steam valve opening setting signal, which sets the reference value of the generated power of the turbine/generator that is operated in synchronization with the power grid, and the turbine speed and the speed deviation signal based on the speed standard. In a turbine control device that controls the output of the turbine/generator by adjusting the opening degree of a steam control valve, the coefficient machine receives the speed deviation signal and sets a speed control gain of the speed deviation signal; a signal limiter that limits the control width of the speed control signal output from the turbine; and a signal limiter that receives the turbine steam valve opening setting signal and generates the speed control signal according to the magnitude of the turbine steam valve opening setting signal. and a function generator for inputting a limit value for limiting at least one of the upper and lower limits to the signal limiter.

(4) The turbine is activated by a signal that is the sum of the turbine steam valve opening setting signal, which sets the reference value of the generated power of the turbine/generator that is operated in synchronization with the power grid, and the turbine speed and speed standard speed deviation signal. In a turbine control device that controls the output of the turbine/generator by adjusting the opening degree of a steam control valve, the coefficient machine receives the speed deviation signal and sets a speed control gain of the speed deviation signal; a signal limiter that limits the control range of the speed control signal output from the turbine; and a signal limiter that receives the turbine steam valve opening setting signal and sets the upper and lower limits of the speed control signal according to the magnitude of the turbine steam valve opening setting signal. a function generator that generates a limit value that limits the control width of at least one of the speed control signals; a signal generator that is set with a limit value that limits the speed control signal to a certain limit width; When operating in synchronization with the power grid, the output signal of the function generator is input to the multiplier, and when the turbine/generator changes from operating in synchronization with the power grid to an isolated operating state, a switching operation is performed. and switching means for inputting the output signal of the signal generator to the multiplier.

(Function) In a turbine control device configured as in item (1) or (3) above, the turbine speed control signal is controlled according to the valve opening setting value, that is, the output setting value of the turbine/generator. By varying the gain or control width according to the valve opening set value, it is possible to operate the boiler stably, and it is possible to suppress fluctuations in steam amount due to turbine speed control, thereby increasing the operational range of frequency control. It can be expanded and contribute to stable load operation of the power system.

In addition to the above-mentioned effects, the turbine control device configured as in item (2) or (4) above also has the following effects:
When the generator is disconnected from the power system and the load fluctuates, the speed control gain or control width of the turbine speed control signal is switched to a constant value that can prevent overspeeding of the turbine.
The turbine speed will not be overspeeded beyond the specified value.

(Example) An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an example of the construction of a turbine control device according to the present invention, and the same parts as in FIG. 6 are shown with the same symbols. As shown in FIG. 1, the actual speed signal S2 of the turbine detected by the speed detector 2 and the reference speed of the turbine set in the reference speed setting device 1, that is, the rated setting speed S
1 is input to the adder 3 to find the deviation between both signals, and this is given to the multiplier 4 as the speed deviation signal S. This multiplier 4 inputs 1 or 2 to the multiplier value output from the signal generator 5 or function generator 6 via a switch 7,
It multiplies the speed deviation signal S and outputs the speed control signal P2. The signal generator 5 outputs a constant multiplier value of 1, and this value is set to a value that provides a turbine speed control gain that prevents the turbine from overspeeding when the turbine/generator load is cut off. has been done. Further, the function generator 6 receives the valve opening setting value P1 of the valve opening setting device 8 as input, and changes depending on the magnitude of the valve opening setting value P1 as shown in FIG. That is, as shown in FIG. 2, in a range where the valve opening degree setting value is low, a small multiplier value of 2 is output, and in a range where the valve opening degree setting value is high, a large multiplier value of 2 is output. Furthermore, the switching device 7 operates in response to a switching command from a detection device (not shown) that operates when it detects that the load of the turbine generator is cut off, and when the turbine/generator is operating in synchronization with the power grid. The multiplier value is switched to the 2 side, and the multiplier value is switched to the 1 side when operating alone or when the load is cut off.

Next, the operation of the turbine control device 0 configured as described above will be described.

Now, when the turbine/generator is operating synchronously with the power grid and the valve opening setting value P1 is large, that is, when the turbine/generator output is large, a large amount of steam generated from the boiler is consumed. , the boiler side can perform stable operation. Therefore, at this time, by increasing the multiplier value output from the function generator 6 by 2, the speed deviation signal S,
Since the turbine speed control gain increases by increasing the output value P2 of the multiplier 4 relative to the current value, active turbine speed control is performed.

In addition, when the valve opening setting value P1 is small, the amount of steam generated from the boiler decreases and the boiler enters an unstable operation region, so the multiplier value is set to 2 to reduce the amount of steam generated from the turbine speed change. By reducing the amount of change in the amount, turbine speed control is performed within a range in which the boiler side can operate.

On the other hand, when the load of the turbine/generator is cut off, the switch 7 switches to the 1 side for the multiplier value, and 1 for the - constant multiplier value.
is input to the multiplier 4 and multiplied by the speed deviation signal M S . This multiplier value is generally set to a value larger than 2, so that the amount by which the steam control valve is closed due to turbine overspeed due to load cutoff becomes large, so that turbine speed control is performed to prevent the turbine from overspeeding.

In this way, in this embodiment, the gain of the turbine speed control is made variable according to the operating output range of the turbine/generator, that is, the steam usage range of the boiler. This makes it possible to continue controlling the turbine speed. Although this will reduce the contribution of frequency control to the power system, the scope of operation will be expanded, and if multiple turbines and generators are collected, it will be possible to contribute more frequency control than before, which will help stabilize the power system. can contribute.

FIG. 3 is a block diagram showing another embodiment of the present invention,
The same parts as in FIG. 6 are shown with the same symbols. As shown in FIG. 3, an adder 3 adds the turbine actual speed signal S2 detected by the speed detector 2 and the turbine reference speed set in the reference speed setting device 1, that is, the rated setting speed S1.
, calculate the deviation between both signals, and convert this into the speed deviation signal S
Coefficient unit 1 with turbine speed control gain set as ,
It is given to 0. The output signal P4 of this coefficient multiplier 10 is input to a signal limiter 11. This signal limiter 11 has a limit value P output from a signal generator 12 or a function generator 13.
6 or P7 is input via the switch 7, and functions to prevent output of a signal larger than the limit setting value P6, and outputs the speed control signal P. in this case,
The signal generator 12 outputs a constant limit value P6,
This value outputs a value that does not limit the human input signal P4 of the signal limiter 11, for example, a large value such as ±100%. A valve opening setting value P is input, and in response to this signal, a limit value P7 having input/output characteristics as shown in Fig. 4 is output.In other words, in the example shown in Fig. f54, the valve opening setting value A large limit value is set when the value P is in a high range, and a small limit value is set when the value P is in a low range.Furthermore, the switch 7 operates when it detects that the load of the turbine generator is cut off, as in the previous embodiment (not shown). The limit value P is switched to P6 by a switching command from the detection device, and the limit value P6 is input to the signal limiter 11 as the limit value P6.

In the turbine control device configured in this way, the limit value P output from the function generator 13 becomes large in the operating range where the boiler side has a large amount of boiler steam that allows stable operation, that is, in the range where the valve opening setting value is high. , through the switch 7 to the signal limiter 11, the turbine speed is actively controlled by the current speed control signal P5. In addition, in a low range of valve opening set value where the boiler side is in an unstable operating region, the signal limit value P7 inputted from the function generator 13 to the signal limiter 11 becomes small, and at this time, the signal limiter 11 outputs Since the variation range of the steam control valve is limited by the speed control signal P, the speed of the turbine is controlled within the range in which the boiler side can be operated.

On the other hand, when the load of the turbine/generator is cut off, the switch 7 switches the signal generator 12 to the circular side, and the constant limit value P6 is input as the limit value P8 of the signal limiter 11. This signal limiter 11 outputs a speed control signal P4 that greatly deviates from the limit range of the output signal P4 of the coefficient multiplier 10 and is not subject to the same limit. As a result, the speed of the turbine is controlled with priority given to overspeed prevention control.

In this way, in the embodiment shown in Fig. 3, the control width of the turbine speed control is made variable according to the output band of the turbine/generator, that is, the steam usage band of the boiler. It becomes possible to continue controlling the turbine speed even in the stable region.

Although this will reduce the contribution to frequency control to the power system, it will expand the scope of operation, so if multiple turbines and generators are collected, it will be possible to contribute more to frequency control than before, which will improve the power system. can contribute to the stabilization of

It goes without saying that the same effect can be obtained by limiting the signal in this embodiment by limiting both the upper limit and the lower limit, or by limiting either the upper limit or the upper limit depending on the operation.

[Effects of the Invention] As described above, according to the turbine control device according to the present invention, the speed control gain or control width of the turbine is varied according to the valve opening setting value of the valve opening setting device. Even in the unstable control region of the boiler, turbine speed control is possible by lowering the turbine speed control gain or reducing the control width, and it is also possible to expand the operational range of turbine speed control, making it possible to improve the power system. It can contribute to stable load operation. In addition, even if the turbine/generator load is cut off when the turbine speed gain is low or the control width is limited, it is possible to control the turbine speed without overspeeding the turbine beyond the specified value. .

[Brief explanation of the drawing]

FIG. 1 is a block circuit diagram showing the configuration of one embodiment of a turbine control device according to the present invention, FIG. 2 is a characteristic diagram of a frequency generator in the same embodiment, and FIG. 3 is a configuration of another embodiment of the present invention. 4 is a characteristic diagram of the frequency generator in the same embodiment, FIG. 5 is a system diagram of power generation equipment in a turbine/generator, and FIG. 6 is a configuration example of a conventional turbine control device. The block circuit diagram, FIG. 7, is a characteristic diagram of turbine speed versus steam valve opening in the same control device. 1... Reference speed setter, 2... Speed detector, 3.9... Adder, 4... Multiplier, 5......・Signal generator, 6...Function generator, 7...Switcher, 8...Valve opening setting device, 10...Coefficient unit, 11... ... Signal limiter, 12 ... Signal generator, 13 ... Function generator, 15 ... Boiler, 16 ... Steam control valve, 17...Turbine・18...
・Condenser, 19... Generator, 20... Breaker, 21... Power system. Applicant's agent Patent attorney Takehiko Suzue Figure 41 2 Figure 2 Figure 3E

Claims (4)

[Claims] (1) The turbine is activated by a signal that is the sum of the turbine steam valve opening setting signal, which sets the reference value of the generated power of the turbine/generator that is operated in synchronization with the power grid, and the turbine speed and speed reference speed deviation signal. A turbine control device that controls the output of the turbine/generator by adjusting the opening degree of a steam control valve, a multiplier that receives the speed deviation signal and sets a speed control gain of the speed deviation signal; a function generator that receives a valve opening setting signal, generates a gain setting signal according to the magnitude of the turbine steam valve opening setting signal, and varies the speed control gain of the speed deviation signal that is input to the multiplier; A turbine control device characterized by comprising: (2) The turbine is activated by a signal that is the sum of the turbine steam valve opening setting signal, which sets the standard value of the generated power of the turbine/generator that is operated in synchronization with the power grid, and the turbine speed and the speed deviation signal based on the speed standard. A turbine control device that controls the output of the turbine/generator by adjusting the opening degree of a steam control valve, a multiplier that receives the speed deviation signal and sets a speed control gain of the speed deviation signal; a function generator that receives a valve opening setting signal and generates a gain setting signal according to the magnitude of the turbine steam valve opening setting signal; a signal generator that outputs a constant gain setting signal; When the turbine/generator is operating in synchronization with the power grid, the gain setting signal generated from the function generator is input to the multiplier, and the turbine/generator is operated in isolation from the state in which it is operating in synchronization with the power grid. 1. A turbine control device comprising: a switching means that performs a switching operation to input an output signal of the signal generator to the multiplier when a state is reached. (3) The turbine is activated by a signal that is the sum of the turbine steam valve opening setting signal, which sets the reference value of the generated power of the turbine/generator that is operated in synchronization with the power grid, and the turbine speed and the speed deviation signal based on the speed standard. In a turbine control device that controls the output of the turbine/generator by adjusting the opening degree of a steam control valve, the coefficient machine receives the speed deviation signal and sets a speed control gain of the speed deviation signal; a signal limiter that limits the control width of the speed control signal output from the turbine; and a signal limiter that receives the turbine steam valve opening setting signal and generates the speed control signal according to the magnitude of the turbine steam valve opening setting signal. A turbine control device comprising: a function generator that inputs a limit value that limits at least one of upper and lower control widths to the signal limiter. (4) The turbine is activated by a signal that is the sum of the turbine steam valve opening setting signal, which sets the reference value of the generated power of the turbine/generator that is operated in synchronization with the power grid, and the turbine speed and speed standard speed deviation signal. In a turbine control device that controls the output of the turbine/generator by adjusting the opening degree of a steam control valve, the coefficient machine receives the speed deviation signal and sets a speed control gain of the speed deviation signal; a signal limiter that limits the control range of the speed control signal output from the turbine; and a signal limiter that receives the turbine steam valve opening setting signal and sets the upper and lower limits of the speed control signal according to the magnitude of the turbine steam valve opening setting signal. a function generator that generates a limit value that limits the control width of at least one of the speed control signals; a signal generator that is set with a limit value that limits the speed control signal to a certain limit width; When operating in synchronization with the power grid, the output signal of the function generator is input to the multiplier, and when the turbine/generator changes from operating in synchronization with the power grid to an isolated operating state, a switching operation is performed. A turbine control device comprising: switching means for inputting an output signal of a signal generator to the multiplier.