RU2315871C1 - System of automatic control of power of steam boiler-turbine power unit - Google Patents

Abstract

FIELD: heat power engineering.

SUBSTANCE: invention can be used in designing systems of automatic control of power of steam boiler-turbine power units, both with drum and with straight-through boilers. In power automatic control system with control of power only by boiler regulator (according to open scheme), fuel flow rate corrector is provided in boiler regulator taking into account influence of instability of calorific power of fuel onto generation of power, efficiency of power unit and influence of change of position of regulating valves of turbine in process of power control.

EFFECT: improved quality of control.

2 cl, 2 dwg

Description

The invention relates to a power system and can be used to create automatic power control systems (CAPM) for power units of a steam boiler - turbine with both drum and once-through boilers.

In recent years, increased attention has been paid to the problem of the effective participation of power units of thermal power plants (TPPs) in regulating the frequency and power flows in the Unified Electric Power System (UES) of Russia. The solution to this problem requires equipping the power units with sufficiently advanced CAPM.

The CAPM of a steam boiler-turbine power unit is known, comprising boiler and turbine power controllers, a driver of a signal deviating from a given value of the frequency or speed of rotation of the turbine rotor, a steam generator and a steam pressure sensor in front of the turbine, a power meter, a fuel consumption meter and a power task generator for both controllers moreover, the boiler power controller as a primary controller contains a fuel consumption controller [1] - a prototype. According to [1], power unit power is controlled only by the boiler controller according to an open circuit (without feedback) with blocking for the time of changing the power of the steam pressure regulator in front of the turbine. Given the complex dynamics of power changes in the process of regulation of a power unit by a boiler, open-loop control greatly simplifies the control system. In this case, however, in order to ensure high accuracy of regulation, it is necessary to issue a correspondingly high-precision power task to the boiler regulator. At the same time, the regulation of the power of the power unit by the boiler is reduced to the effect of the power task on the fuel supply regulator, the calorific value of which practically does not remain constant. In addition, the lack of accuracy in issuing tasks for power is also due to the error in measuring fuel consumption and deviations of the efficiency of the power unit from the calculated value, which is one of the disadvantages of the prototype.

The achieved result of the invention is to improve the quality of regulation by increasing the accuracy of the formation of tasks for power with an open automatic control system.

This result is achieved by the fact that the CAPM of the power unit of the steam boiler is a turbine containing boiler and turbine power regulators, a signal shaper of deviation from the set value of the frequency or speed of rotation of the turbine rotor, a steam generator and a steam pressure sensor in front of the turbine, a power meter, a fuel consumption meter and a task shaper in power for both regulators, moreover, the boiler power regulator as a primary regulator contains a fuel consumption regulator, according to the invention additionally neighbors the shaper of the task to the fuel consumption regulator, the corrector of the task of fuel consumption to the specified shaper and the driver of the control action on the turbine power regulator, one of the inputs of the driver of the task of the fuel regulator is connected to the output of the driver of the task of power for both regulators, the other to the output of the specified corrector, the inputs control action shapers are connected to the output of the task shaper by the power of both regulators, the setter by the pressure at the turbine inlet and dates iku said pressure.

The specified fuel consumption task corrector, according to the invention, may include a differentiator, an adder, a divider and two dampers, the input of the differentiator connected to a steam pressure sensor in front of the turbine, the output to one of the inputs of the adder, to the other input of which the output of the power meter is connected, output the adder is connected to one of the inputs of the divider, the other input of which is connected to the output of the first damper, the input of which is connected to the fuel consumption meter, and the output of the divider is connected to the input of the second damper, the output of which I It is output by the corrector.

Figure 1 shows the CAPM according to the invention with elements of an adjustable technological scheme of the power unit; figure 2 is a structural diagram of the CAPM according to the invention.

The technological scheme of the power unit (Fig. 1) includes a steam boiler K 1 with a fuel line 2 and a fuel control valve 3, a steam turbine T 4 with an electric generator 5 and a steam pipe 6 with a superheater 7 and control valves 8 for supplying steam to the turbine T 4.

CARM power unit of a steam boiler K 1 - turbine T 4 contains a boiler power regulator (not shown) with a fuel consumption regulator PPT 9 as a primary regulator, a turbine power regulator TPM 10, a signal shaper deviation from the set frequency or rotation speed of the turbine rotor FSOCH 11, a master and a sensor, respectively, 12, 13 of the steam pressure in front of the turbine T 4, power meter IM 14, fuel consumption meter ИРТ 15 and power task generator ФЗМ 16 for both controllers. The CAPM also contains a shaper of the task for the fuel consumption regulator FZRT 17, a corrector for the task for fuel consumption KZRT 18 and a shaper of the control action of the FUV 19 on the TPM 10. In this case, one of the inputs of the FZRT 17 is connected to the output of the FZM 16, the other to the output of the KZRT 18, the inputs of the FU 19 are connected to the output of the FSM 16, the setter 12 by pressure at the inlet to the turbine T 4 and the sensor 13 of the specified pressure.

KZRT 18 takes into account the instability of the qualitative characteristics of the combusted fuel and the effect of changes in steam pressure in front of the turbine T 4 caused by the movement of its control valves 8. According to the invention it contains (figure 2) a differentiator D 20, an adder 21, a divider 22 and two dampers, respectively 23 and 24 moreover, the input of the differentiator D 20 is connected to the steam pressure sensor 13 in front of the turbine T 4 (Fig. 1) that generates a signal p _t ', the output to one of the inputs of the adder 21 (Fig. 2), to the other input of which the IM 14 output is connected (figure 1) generating a signal N, the output of the adder 21 is connected to one of the inputs of the divider 22 (figure 2), the other input of which is connected to the output of the first damper 23, the input of which is connected to the ИРТ 15 (figure 1), which generates the signal F _t , and the output of the divider 22 to the input of the second damper 24 (figure 2).

и датчику 13 давления пара перед турбиной 4 (фиг.1), вырабатывающему сигнал p_т'. Выход сумматора 28 является выходом ФУВ 19.CAPM, according to the invention, also contains a turbine power regulator unit BTRM 25 (Fig. 2), which includes a driver for controlling the action of the FUV 19 on the TPM 10, the TPM 10 itself and the control mechanism of the turbine MUT 26. The FUV 19, in turn, contains a DP dynamic converter 27 and the adder 28, and the input of the DP 27 is connected to the output of the FSM 16, and the output is to the first input of the adder 28. The other two inputs of the adder 28 are connected respectively to the master 12 that generates a signal

and a steam pressure sensor 13 in front of the turbine 4 (FIG. 1) generating a signal p _t '. The output of the adder 28 is the output FUV 19.

FZM 16 (figure 2) contains an adder 29 and a shaper of the task according to the primary power of FZPM 30 based on the signal Δf (Δn) generated by the HSE 11 according to the deviation from the set value of the frequency f or speed n of rotation of the turbine rotor T 4. In this case, one of the inputs of the adder 29 is connected to the master of the planned component of power N _health (not shown), the second input is to the master of the unplanned component of power N _health (not shown), the third input is to the output of the MPS 30, the input of which is connected to the sensor 11 (figure 1) deviations from the set value of the sludge frequency Turbine rotor speed T 4. The output of adder 29 is the output 16 FGM.

и

по давлению пара перед турбиной Т 4. Выходной сигнал от сумматора 28, пройдя ТРМ 10 и МУТ 26, преобразуется в сигнал Н_т перемещения регулирующих клапанов 8 турбины Т 4 (фиг.1). При этом ТРМ 10 получает основной сигнал по небалансу между фактическим

и заданным

значениями давления пара перед турбиной Т 4 и динамический исчезающий сигнал по N_зд, формируемый динамическим преобразователем ДП 27 и предназначенный для компенсации изменения

при перемещении Н_т.CAPM power unit, according to the invention, operates as follows. When you change one of the components of the task in terms of power N _{health pl} , N _{health npl} , N _{health first} (the latter is formed in FZPM 30 (figure 2) by multiplying the signal proportional to the change Δf frequency or Δn of the speed of rotation of the turbine rotor T 4, _prim to K - coefficient determining droop primary regulation) N resultant signal _zd reference power output from FGM 16 arrives at RRT 9 (Fig.1) and TPM 10 (Figures 1 and 2). When an N _zd signal proportional to it the task of changing the fuel flow rate F _t.zd, leading to a consistent change in fuel consumption, air and the feedwater. At the same time, on PPT 9, the signal N _rear comes through FZRT 17, which generates the output signal of the reference for fuel consumption F _tzd = N _rear (F _t / N) _cp , where (F _t / N) _cp is the average ratio of fuel consumption to the current power value. This ratio is obtained by dividing in the divider 22 (FIG. 2) the signal according to F _t , passed through the first damper 23, by the sum of the signal according to N and the disappearing signal generated by the differentiator D 20 by the vapor pressure p _t 'in front of the turbine T 4. If correctly configured of the differentiator D 20, the indicated sum N + dp _n / dt practically does not react to the deviation of the position of the control valves 8 and at the same time changes intensively with a change in F _t . The first damper 23 is adjusted in such a way as to bring its dynamic characteristics closer to the dynamics of changes N + dp _n / dt with a disturbance F _t . The output signal of the divider 22 is additionally smoothed by the second damper 24. Thus, at a constant calorific value of the fuel, a change in F _t does not lead to a significant change (F _t / N) _cp , which leads to a high quality of control over the channel F _t in an open loop. A signal proportional to the specified ratio is generated in KZRT 18. The reference signal for power N _rear , fed to the TPM 10 in the BTRM 25 (Fig. 2), is fed to the input of the DP 27 and after conversion is summed in the adder 28 with the reference and current signals, respectively

and

according to the steam pressure in front of the turbine T 4. The output signal from the adder 28, passing TPM 10 and MUT 26, is converted into a signal N _{t the} movement of the control valves 8 of the turbine T 4 (figure 1). In this case, TPM 10 receives the main signal by the imbalance between the actual

and given

the values of the steam pressure in front of the turbine T 4 and the dynamic disappearing signal in N _rear , generated by the dynamic transducer DP 27 and designed to compensate for the change

when moving N _t

Thus, the technical solution according to the invention provides high quality power unit power control by a boiler controller in an open control system.

The source of information

1. Copyright certificate SU No. 691586, F01K 13/02, 1976.

Claims (2)

1. A system for automatically controlling the power of a steam boiler power unit — a turbine containing boiler and turbine power controllers, a signal shaper for deviating from the set value of the frequency or speed of rotation of the turbine rotor, a steam generator and a steam pressure sensor in front of the turbine, a power meter, a fuel consumption meter, and a task driver for power for both regulators, and the boiler power regulator as a primary regulator contains a fuel consumption regulator, characterized in that the additional system It contains the task driver for the fuel consumption regulator, the task corrector for fuel consumption for the specified driver and the driver for the control action on the turbine power regulator, one of the inputs of the task driver for the fuel regulator connected to the output of the task driver for power for both controllers, and the other for the output of the specified corrector, the inputs of the driver of the control action are connected to the output of the driver of the task by the power of both regulators, the master by the pressure at the input to t urbine and the specified pressure sensor. 2. The automatic control system according to claim 1, characterized in that the fuel consumption corrector contains a differentiator, an adder, a divider and two dampers, the input of the differentiator connected to a steam pressure sensor in front of the turbine, the output to one of the adder inputs, to the other the input of which is connected to the output of the power meter, the output of the adder is connected to one of the inputs of the divider, the other input of which is connected to the output of the first damper, the input of which is connected to the fuel consumption meter, and the output of the divider to the second input th damper whose output is the output of the equalizer.

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