阅读说明：本技术 一种汽机旁路系统单回路双调节对象控制方法 (Single-loop double-regulation-object control method for steam turbine bypass system ) 是由 吴智君 何炜煜 崔承永 穆娜 程谦烨 董春鹂 于 2021-08-31 设计创作，主要内容包括：本发明公开了一种汽机旁路系统单回路双调节对象控制方法,在常规的高旁控制的基础上,继续保持单回路控制策略不变,确保自动控制能够快速响应机组运行工况要求；在原来的一个PID模块控制一个调节对象的基础上,增加为两个PID模块分别控制两个调节对象,两个PID模块共用一个阀门操作模块；但是不同于串级回路控制,这两个PID是各自独立的,各自形成各自的单回路控制：PID1控制高旁阀后压力,PID2控制高旁阀前压力。本发明可以根据机组的实际运行情况,由运行人员去选择调节对象,双调节对象切换为勿扰切换,避免调节对象切换后造成系统扰动,保证机组运行供热安全稳定,能够提高设备自动控制效率。(The invention discloses a single-loop double-regulation-object control method of a steam turbine bypass system, which is characterized in that on the basis of conventional high-bypass control, a single-loop control strategy is continuously kept unchanged, and the requirement of a unit on operation conditions can be quickly responded by automatic control; on the basis that one original PID module controls one regulating object, two PID modules are added to respectively control the two regulating objects, and the two PID modules share one valve operation module; but unlike cascade loop control, the two PIDs are independent of each other, each forming a respective single loop control: PID1 controls high bypass valve back pressure and PID2 controls high bypass valve front pressure. According to the invention, the operator can select the regulating object according to the actual running condition of the unit, and the double regulating objects are switched to do not disturb switching, so that system disturbance caused by the switching of the regulating objects is avoided, the safety and stability of unit running heat supply are ensured, and the automatic control efficiency of equipment can be improved.)

1. A single-loop double-regulation-object control method for a steam turbine bypass system comprises the following steps:

s1: selecting two PID modules which are respectively a PIDA01 module and a PIDAO2 module, wherein the PIDA01 module and the PIDAO2 module are mutually independent and respectively form an independent single-loop control system, the PID01 module takes the rear outlet steam pressure of a high bypass valve as an adjusting object, and the PID02 module takes the front main steam pressure of the high bypass valve as an adjusting object;

s2: selecting a manual selection button module, and connecting the manual selection button module with the PIDA01 module and the PIDAO2 module respectively, wherein the logical connection relationship between the manual selection button module and the PIDA01 module and the PIDA02 module is opposite, that is, if the manual selection button module is in positive connection with the PIDA01 module, the manual selection button module is in negative connection with the PIDA01 module;

s3: the PIDA01 module, the PIDAO2 module and the manual selection button module are all connected with the SWCH analog quantity selection module;

s4: first selecting, by the manual selection button module, whether the PIDA01 module is in the automatic position or the PIDA02 module is in the automatic position, and once it is determined that one of them is in the automatic position, the other is in the manual position;

s5: after selection, the selected PID output instruction is transmitted to an MSA1 high bypass adjusting valve manual operation module through the SWCH analog quantity selection module, control of a single-loop double-PID adjusting object is completed, and a closed loop is formed.

2. The single-loop double-regulation-object control method of the steam turbine bypass system according to claim 1, characterized by comprising the following steps of: the adjusting object of the PIDA01 module and the adjusting object of the PIDAO2 module are not disturbed when being switched, an auxiliary protection logic for automatically switching to a manual position is further arranged in single-loop double-PID adjustment, and when the main steam pressure is totally bad or a bad quality instruction is fed back by a high-pressure bypass pneumatic adjusting door, the system is automatically switched to the manual position;

and when the absolute value of the difference between the control instruction of the high-pressure bypass pneumatic adjusting door and the feedback of the high-pressure bypass pneumatic adjusting door is larger than 15, the system is automatically switched to a manual position.

3. The single-loop double-regulation-object control method of the steam turbine bypass system according to claim 2, characterized by comprising the following steps of: when the absolute value of the difference between the set value and the actual value of the high-side post-pressure is larger than 0.5, the system is in the high-side post-pressure control loop and the loop is in an automatic state, the system is switched from the automatic position to the manual position.

4. The single-loop double-regulation-object control method of the steam turbine bypass system according to claim 3, characterized by comprising the following steps of: when the absolute value between the set value of the high bypass front pressure and the actual value of the main steam pressure regulation is larger than 0.5, the system is in the high bypass rear pressure control loop, and the loop is in an automatic state, the system is switched to a manual position from an automatic position.

5. The single-loop double-regulation-object control method of the steam turbine bypass system according to claim 1, characterized by comprising the following steps of: in the single-loop double-PID regulation, auxiliary logic for controlling the opening degree of a bypass of the steam turbine is further arranged, and under the condition that the steam turbine is tripped, the active power value of the steam turbine generator is greater than or equal to 7, and the valve command value is smaller than 30, the command for forcibly regulating the opening degree of the valve is transmitted to the MSA1 high bypass regulating valve hand operation module for forcibly regulating the opening degree.

6. The single-loop double-regulation-object control method of the steam turbine bypass system according to claim 5, characterized by comprising the following steps of: the opening degree can itself be selected in the opening degree module CHAR.

Technical Field

The invention relates to a steam turbine bypass control method, in particular to a single-loop double-regulation-object control method of a steam turbine bypass system.

Background

At present, with the continuous improvement of the national requirement on clean energy, the distributed energy heat supply unit is developed rapidly in various industrial parks at present, a gas combined cycle heat supply unit is often only used as an auxiliary heat supply workshop for industrial production, and a conventional steam turbine bypass system mainly controls the pressure of the gas before a high bypass valve so as to realize the normal running and the stable operation of the unit or control the pressure after the high bypass valve so as to maintain the stable heat supply pressure.

However, the gas combined unit mainly takes heat supply as a main part and also takes power generation into consideration. Therefore, when the unit is in different working conditions, the steam turbine bypass system has different adjusting objects, so that the steam turbine bypass system is required to give consideration to the adjustment of the pressure before the valve, the stable operation of the unit is ensured, and the adjustment of the pressure after the valve is also required to ensure the stable heat supply.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: the method overcomes the defects of the prior art, and provides the single-loop double-regulation-object control method of the steam turbine bypass system, which can improve the automatic control efficiency of the equipment.

The technical scheme adopted by the invention for solving the technical problem is as follows:

a single-loop double-regulation-object control method for a steam turbine bypass system comprises the following steps:

s1: selecting two PID modules which are respectively a PIDA01 module and a PIDAO2 module, wherein the PIDA01 module and the PIDAO2 module are mutually independent and respectively form an independent single-loop control system, the PID01 module takes the rear outlet steam pressure of a high bypass valve as an adjusting object, and the PID02 module takes the front main steam pressure of the high bypass valve as an adjusting object;

s2: selecting a manual selection button module, and connecting the manual selection button module with the PIDA01 module and the PIDAO2 module respectively, wherein the logical connection relationship between the manual selection button module and the PIDA01 module and the PIDA02 module is opposite, that is, if the manual selection button module is in positive connection with the PIDA01 module, the manual selection button module is in negative connection with the PIDA01 module;

s3: the PIDA01 module, the PIDAO2 module and the manual selection button module are all connected with the SWCH analog quantity selection module;

s4: first selecting, by the manual selection button module, whether the PIDA01 module is in the automatic position or the PIDA02 module is in the automatic position, and once it is determined that one of them is in the automatic position, the other is in the manual position;

s5: after selection, the selected PID output instruction is transmitted to an MSA1 high bypass adjusting valve manual operation module through the SWCH analog quantity selection module, control of a single-loop double-PID adjusting object is completed, and a closed loop is formed.

The adjusting object of the PIDA01 module and the adjusting object of the PIDAO2 module are switched with each other without disturbance,

in the single-loop double-PID regulation, an auxiliary protection logic for automatically switching to a manual position is also arranged, and when the main steam pressure is totally bad or a bad quality instruction exists in the feedback of the high-pressure bypass pneumatic regulation gate, the system is automatically switched to the manual position;

and when the absolute value of the difference between the control instruction of the high-pressure bypass pneumatic adjusting door and the feedback of the high-pressure bypass pneumatic adjusting door is larger than 15, the system is automatically switched to a manual position.

When the absolute value of the difference between the set value and the actual value of the high-side post-pressure is larger than 0.5, the system is in the high-side post-pressure control loop and the loop is in an automatic state, the system is switched from the automatic position to the manual position.

When the absolute value between the set value of the high bypass front pressure and the actual value of the main steam pressure regulation is larger than 0.5, the system is in the high bypass rear pressure control loop, and the loop is in an automatic state, the system is switched to a manual position from an automatic position.

In the single-loop double-PID regulation, auxiliary logic for controlling the opening degree of a bypass of the steam turbine is further arranged, and under the condition that the steam turbine is tripped, the active power value of the steam turbine generator is greater than or equal to 7, and the valve command value is smaller than 30, the command for forcibly regulating the opening degree of the valve is transmitted to the MSA1 high bypass regulating valve hand operation module for forcibly regulating the opening degree.

The opening degree can itself be selected in the opening degree module CHAR.

The method can be applied to various scenes, not only pressure, but also other control fields such as temperature, flow, liquid level and the like, and has wide application range and strong practicability.

The invention has the following positive beneficial effects:

1. the invention adopts the single-loop double-PID module to respectively control the pressure before the high-side valve and the pressure after the high-side valve, the parameters of the two PID modules are different due to different adjusting objects, and the operating personnel can randomly select the PID module according to the operating requirement of the unit, thereby ensuring the safety and stability of the heat supply during the operation of the unit.

2. The automatic control between the two PID modules can perform undisturbed switching, meet the operation requirements under various working conditions, lighten the operation steps of operators, reduce the error rate and improve the working efficiency.

3. When the PDI output is selected, the PB01 selection button is also used as a condition for selecting corresponding PID manual/automatic switching, so that when a manual operator is put into automation, the corresponding PID is in an automatic position, the other PID is in a manual position, when the PB01 switches the output of the PID module, the other PID in the manual position is switched into the automatic position without disturbance, and the switched PID module is changed from the automatic position into the manual position, so that the operation steps when an operator switches an adjusting object are reduced, operation errors which possibly occur are avoided, and the automatic control efficiency of equipment is improved.

Drawings

FIG. 1 is a schematic diagram of the logic between a PIDA01 module and a PIDAO2 module of the present invention;

FIG. 2 is a logic diagram of the auxiliary protection for automatic switching to manual bit in the present invention;

fig. 3 is an auxiliary logic diagram of the opening degree control in the present invention.

Detailed Description

The invention will be further explained and explained with reference to the accompanying drawings, fig. 1, fig. 2, fig. 3 and the specific embodiments:

example (b): the gas combined cycle heat supply unit is designed to use heat to fix power, mainly uses heat supply as a main part, and the bypass system is designed to have 100% capacity, so that the gas combined cycle heat supply unit is not only responsible for starting a steam turbine, but also responsible for supplying heat to an industrial park.

The high-pressure steam of the unit is mainly used for heat supply, has high requirements on heat supply quality and stability, is mainly extracted by a steam turbine or is realized by a high-pressure bypass, and because the generating capacity of the gas turbine is large, the power generation requirement of a plant area on a steam turbine generator is low, so that more working conditions and states ensure stable heat supply of the unit and safe and stable operation of a gas combined unit.

The bypass system mainly comprises a high-pressure bypass and a low-pressure bypass, and the inlet pressure of the high-pressure bypass is regulated by a high bypass regulating valve and a low bypass regulating valve respectively; the low-pressure bypass is only responsible for adjusting the pressure of the low-side outlet, the process flow is simple, and the adjusting object is clear.

The high-pressure bypass is relatively complex and needs to be responsible for two regulating objects, one regulating object is the inlet pressure of the high bypass, and the regulating object is to control the gas supply pressure when the steam turbine is started, stopped and operated; the other regulating object is high-pressure bypass outlet pressure, and the regulating object is to control the heat supply pressure of the industrial park and ensure the heat supply stability.

The two regulating objects use respective independent PID parameters, so that the problems that the parameters are not appropriate and disturbance is increased when the regulating objects are switched are avoided, the automatic control and regulation quality is influenced, the continuous and stable heat supply can be ensured on the premise of ensuring the safety and stability of a unit, the frequent starting and stopping of a combustion engine caused by the operation of a steam turbine or heat supply are avoided, the pressure is regulated before a high bypass valve, the pressure is mainly an important monitoring object when the steam turbine is started and rushed to rotate, and the pressure is also a main regulating object when the steam turbine is started, operated and stopped; high by-pass valve back pressure, this bypass is 100% capacity heat supply bypass, therefore valve back pressure is the heating system main regulation object.

In order to meet the complexity of the high-side process design, the conventional high-side automatic control needs to be modified and upgraded, a new control strategy is designed, and meanwhile, the operation of operators is also facilitated:

on the basis of conventional high-side control, a single-loop control strategy is continuously kept unchanged, and the requirement of the unit on the running condition can be quickly responded by automatic control; on the basis that one original PID module controls one regulating object, two PID modules are added to respectively control the two regulating objects, and the two PID modules share one valve operation module; but unlike cascade loop control, the two PIDs are independent of each other, each forming a respective single loop control: PID1 controls pressure behind the high side valve, PID2 controls pressure in front of the high side valve, and can be selected by operators according to the actual running condition of the unit, and the double regulating objects are switched to be not disturbed to be switched, so that system disturbance caused by switching of the regulating objects is avoided.

The reliability and the correctness of automatic control are verified under the working conditions of each stage of unit starting, heat supply, loaded operation, stopping and the like, in the implementation process, the stability of each parameter of the bypass system is observed, the safety and the normality of each system are ensured, if abnormity occurs, manual intervention is required to be rapidly carried out, and the operation is automatically switched to manual operation.

The method specifically comprises the following steps:

s1: selecting two PID modules which are respectively a PIDA01 module and a PIDAO2 module, wherein the PIDA01 module and the PIDAO2 module are mutually independent and respectively form an independent single-loop control system, and the PID01 module takes the outlet steam pressure after a high bypass valve as an adjusting object and is used for maintaining the stability of the heat supply pressure; the PID02 module takes the main steam pressure before the high bypass valve as the regulating object and is used for maintaining the normal start and stop of the steam turbine.

S2: selecting a manual selection button module, and respectively connecting the manual selection button module with the PIDA01 module and the PIDAO2 module, wherein the logical connection relationship between the manual selection button module and the PIDA01 module and the PIDA02 module is opposite, namely if the manual selection button module is positively connected with the PIDA01 module, the manual selection button module is negatively connected with the PIDA01 module;

s3: the PIDA01 module, the PIDAO2 module and the manual selection button module are all connected with the SWCH analog quantity selection module;

s4: firstly, whether the PIDA01 module is in the automatic position or the PIDA02 module is in the automatic position is selected through a manual selection button module, and once one of the PIDA01 module and the PIDA02 module is determined to be in the automatic position, the other PIDA is in the manual position;

s5: after selection, the selected PID output instruction is transmitted to an MSA1 high bypass control valve manual operation module through an SWCH analog quantity selection module, control of a single-loop double-PID control object is completed, and a closed loop is formed.

Because the control strategy designs the automatic control of the high-pressure bypass system as a single-loop double-PID double-regulation object, the auxiliary protection logic of the automatic control switching operation can not simply switch the automatic switching operation according to the set value and the tracking value with large deviation, but respectively treat the automatic switching operation according to the selected PID loop, the specific method is that a PB01 button is also used as the condition of the switching operation, when one PID module is selected as the automatic, only the set value and the tracking value corresponding to the PID module are protected and do not work, and after the regulation object is switched, the corresponding set value and the tracking value deviation protection are also switched.

When the main steam pressure is totally bad or a bad quality instruction exists in the feedback of the high-pressure bypass pneumatic adjusting valve, the system is automatically switched to a manual position; when the absolute value of the difference between the control instruction of the high-pressure bypass pneumatic adjusting door and the feedback instruction of the high-pressure bypass pneumatic adjusting door is larger than 15, the system is automatically switched to a manual position.

When the absolute value of the difference between the set value and the actual value of the high-side post-pressure is larger than 0.5, the system is in the high-side post-pressure control loop and the loop is in an automatic state, the system is switched from the automatic position to the manual position.

When the absolute value between the set value of the high bypass front pressure and the actual value of the main steam pressure regulation is larger than 0.5, the system is in the high bypass rear pressure control loop, and the loop is in an automatic state, the system is switched to a manual position from an automatic position.

The steam turbine bypass system not only has manual auxiliary protection logic, but also has other specific auxiliary logic which is generally designed according to the operation of the unit and the actual use condition of an owner. For example, when the electric load is larger than a predetermined value, the opening degree of the bypass of the turbine is required.

Under the combined action that the steam turbine is tripped, the active power value of the steam turbine generator is greater than or equal to 7, and the valve instruction value is smaller than 30, an instruction of forcing the opening of the regulating valve is transmitted to an MSA1 high bypass regulating valve hand operation module to regulate the opening, and the opening can be selected in an opening module CHAR.

The invention is not limited to the above embodiments, and those skilled in the art can make equivalent modifications or substitutions without departing from the spirit of the invention, and such equivalent modifications or substitutions are included in the scope defined by the claims of the present application.