CN117167667A - Protection system and protection method for automatic regulation and control of pipeline flow - Google Patents

Abstract

The invention relates to a protection system and a protection method for automatic regulation and control of pipeline flow, wherein the protection system comprises a flowmeter and a regulating valve which are arranged on a pipeline, wherein the flowmeter is used for collecting medium flow data in the pipeline, the regulating valve is used for regulating the medium flow in the pipeline, the protection system also comprises a main controller, an analog input module and an analog output module, the main controller is used for controlling and regulating the medium flow in the pipeline, the collected data of the flowmeter is transmitted to the main controller through the analog input module, the main controller compares and calculates the collected data, and then a control signal is output to the regulating valve through the analog output module, and the regulating valve is used for regulating and controlling the medium flow in the pipeline. When the abnormal condition appears in the flowmeter, can be with the regulator by automatic switch to manual, prevent that the governing valve from also undulant by a wide margin, avoid leading to production and technology index to appear undulant because of the problem of flowmeter to guarantee personal safety and production operating mode, running equipment's stability.

Description

A protection system and protection method for automatic adjustment and control of pipeline flow

Technical field

The invention belongs to the technical field of flow control, and specifically relates to a protection system and a protection method for automatic adjustment and control of pipeline flow.

Background technique

In the field of industrial control, especially the petrochemical industry, automatic flow adjustment control is often used to control process flows. This control system can greatly reduce the workload of operators, and the control is relatively accurate and smooth. Automatic adjustment control is widely used. It can improve the automation level of enterprises.

However, in the actual operation process, the analog signals collected from the on-site flow meter may have various abnormal situations. If there is no judgment and differentiation of data quality, the control system is likely to make wrong judgments, thereby triggering a series of Wrong action instructions may cause the controller to issue wrong instructions to the regulating valve after calculation, causing large fluctuations in the regulating control, and may even cause safety production accidents, which is very detrimental to safe and stable production.

Contents of the invention

In view of the above situation, the present invention provides a protection system and protection method for automatic flow adjustment control of pipelines to solve the technical problems that are prone to abnormality in the existing automatic flow adjustment control technology. When the instrument data is abnormal, the speed changes by Speed and amplitude are used to distinguish the quality of data and avoid erroneous instructions, thereby ensuring the safety and stability of production.

In order to achieve the above objectives, the present invention adopts the following technical solutions:

A protection system for automatic adjustment and control of pipeline flow, including a pipeline and a flow meter and a regulating valve installed on the pipeline. The flow meter is used to collect medium flow data in the pipeline, the regulating valve is used to adjust the medium flow in the pipeline, and the flow meter and regulating valve settings are common settings for pipelines in the chemical industry.

The protection system for automatic adjustment and control of pipeline flow of the present invention also includes a main controller, an analog input module and an analog output module. The main controller is used to control and adjust the medium flow in the pipeline, and the collected data of the flow meter is input through the analog input module. The module is transmitted to the main controller, which performs a comparison operation on the collected data, and then outputs a control signal to the regulating valve through the analog output module, and the regulating valve performs regulation and control of the medium flow in the pipeline.

Furthermore, the main controller adopts the DCS system of ECS-700. The main controller is equipped with data quality judgment protection, deviation rate change protection, data filtering protection and abnormal alarm function programs to control and protect the flow adjustment process. .

Furthermore, a regulator function block is provided in the main controller, which can switch between manual and automatic adjustment functions of the regulating valve.

Further, the flow meter transmits data with the analog input module through an analog input signal of 4 to 20 mA; the analog output module controls the action of the regulating valve through an analog output signal of 4 to 20 mA.

The specific steps of the protection method of the above-mentioned pipeline flow automatic adjustment and control protection system include:

S1. The main controller adopts the DCS system of ECS-700, installs the deviation rate change protection program, data quality judgment protection program, and data filtering protection program on the main controller, and sets the flow data threshold; making it capable of data quality judgment Protection, deviation rate change protection, data filtering protection and abnormal alarm functions.

S2. The flow meter collects the medium flow data in the pipeline and transmits it to the main controller with an analog input signal of 4~20mA through the analog input module; due to the actual operation process, the analog signal collected from the on-site flow meter may appear Various abnormal situations will cause the controller to issue wrong instructions to the regulating valve after calculation, causing large fluctuations in pipeline flow regulation control, which is very detrimental to safe and stable production. Therefore, it is necessary to judge the data quality of the flow meter to prevent errors. Command output to realize the protection of automatic adjustment and control of pipeline flow;

S3. The DCS system of the main controller calculates and compares the collected data; when the collected data exceeds the upper and lower limits of the threshold, it is judged as data abnormality and an alarm is issued; first, an alarm for data exceeding the limit abnormality will be given. Prompt the operator to pay attention; at the same time, output an instruction to the automatic adjustment control program, so that the adjustment control switches the main controller from automatic mode to manual mode, preventing the adjustment valve from making erroneous actions following abnormal over-limit flow;

S4. When the collected data is within the threshold range, it is judged that the data is normal. At this time, the main controller is in the automatic control mode. The main controller controls the action of the regulating valve with an analog output signal of 4~20mA to control the medium flow in the pipeline. Make automatic adjustments.

The present invention also includes other components that can be used normally, which are conventional means in this field. In addition, devices or components that are not limited in the present invention, such as: pipeline flow meters, regulating valves, main controllers, analog inputs Modules, analog output modules, as well as the ECS-700's DCS system and deviation rate change protection program, data quality judgment protection program, data filtering protection program, etc., all adopt the existing technology in this field.

The beneficial effects of the present invention are as follows:

The invention provides a protection system and protection method for automatic adjustment and control of pipeline flow. Through the use of the deviation rate change protection program, the data quality judgment protection program, and the data filtering protection program, when an abnormality occurs in the flow meter, the regulator can be Switching from automatic to manual prevents the regulating valve from fluctuating significantly, which can well avoid fluctuations in production and process indicators due to problems with the flow meter, thereby ensuring personal safety and the stability of production conditions and operating equipment.

Description of drawings

Figure 1 is a block diagram of the connection relationship of the protection system for automatic adjustment and control of pipeline flow in the embodiment.

Figure 2 is a block diagram of the process steps of the protection method for automatic adjustment and control of pipeline flow in the embodiment.

Detailed ways

The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention.

Example

As shown in Figure 1, a protection system for automatic adjustment and control of pipeline flow includes a pipeline, a flow meter FI and a regulating valve FV installed on the pipeline. The flow meter is used to collect the medium flow data in the pipeline, and the regulating valve is used to regulate The medium flow rate, flow meter and regulating valve settings in the pipeline are all conventional settings for pipelines in the chemical industry.

The protection system for automatic adjustment and control of pipeline flow also includes the main controller CPU, the analog input module AI and the analog output module AO. The main controller is used to control and adjust the medium flow in the pipeline. The collected data of the flow meter FI passes through the analog input module. The input module AI is transmitted to the main controller CPU, and the main controller performs a comparison operation on the collected data, and then outputs a control signal to the regulating valve FV through the analog output module AO, and the regulating valve performs the regulation of the medium flow in the pipeline. control.

The main controller adopts the DCS system of ECS-700. The main controller is equipped with data quality judgment protection, deviation rate change protection, data filtering protection and abnormal alarm function programs to control and protect the flow adjustment process. The main controller is equipped with a regulator function block, which can switch between manual and automatic adjustment functions of the regulating valve.

Under normal circumstances, the regulator function block in the main controller can perform manual and automatic adjustment of the regulating valve. When it is in manual mode, the operator inputs the value of the regulator's output to control the adjustment; when it is in automatic mode, the regulator's output is calculated based on the comparison between the value of the flow meter and the operator's set value, and then the control value is output. The adjustment is controlled, reducing the workload of the operator, and the control is relatively precise and smooth.

The flow meter transmits data with the analog input module through an analog input signal of 4 to 20 mA; the analog output module controls the action of the regulating valve through an analog output signal of 4 to 20 mA.

When the flow meter is affected by external influences or its own faults, the output value of the flow meter will fluctuate greatly. If automatic is selected at this time, the regulator will output a large fluctuation according to the fluctuation of the flow meter. This causes the regulating valve to fluctuate significantly, eventually causing the flow in the pipeline to be out of control, affecting production safety and the stability of process indicators.

In the regulator control function, a deviation rate change protection program is added. When there is a large fluctuation in the flow meter and the front and rear deviation is greater than the preset value, it is considered that the flow meter has an abnormality. At this time, the regulator is switched from automatic to manual to prevent the regulating valve from also fluctuating greatly and avoid affecting safe production and technology. The indicator is stable.

As shown in Figure 2, the protection method of the above-mentioned pipeline flow automatic adjustment and control protection system, the specific steps include:

S1. Install the deviation rate change protection program, data quality judgment protection program, and data filtering protection program on the main controller, and set the flow data threshold; the main controller adopts the DCS system of ECS-700, which has data quality judgment protection, deviation rate Change protection, data filtering protection and abnormal alarm functions.

S2. The flow meter collects the medium flow data in the pipeline and transmits it to the main controller with an analog input signal of 4~20mA through the analog input module.

S3. The DCS system of the main controller calculates and compares the collected data; when the collected data exceeds the upper and lower limits of the threshold, it is determined that the data is abnormal and an alarm is issued.

S4. When the collected data is within the threshold range, it is judged that the data is normal. At this time, the main controller is in the automatic control mode. The main controller controls the action of the regulating valve with an analog output signal of 4~20mA to control the medium flow in the pipeline. Make automatic adjustments.

Data quality judgment:

When the data suddenly appears to be greater than or equal to the upper limit of the measurement range or less than or equal to the lower limit of the measurement range, the data is judged to be abnormal. First, a data over-limit exception alarm will be given, prompting the operator to pay attention and handle it. At the same time, an instruction is output to the automatic adjustment control program to switch the adjustment control from automatic mode to manual mode to prevent the adjustment valve from making erroneous actions following abnormal over-limit flow.

Deviation rate calculation:

Subtract the flow value collected in the previous scan cycle of the controller from the flow value collected in the next scan cycle to obtain the deviation value of the flow rate in one scan cycle. Perform an absolute value operation on the obtained deviation value to obtain a positive deviation value. Compare this value to the set value.

If it is lower than the set value ①, it is considered normal and the automatic adjustment control operates normally.

When it is greater than or equal to the set value ① and less than the set value ②, it is considered that the data has begun to have unstable factors such as small fluctuations, and the setting protection of the filter time is triggered in time, and the data is automatically optimized and a data is given The filtered alarm prompts the operator to pay attention and handle it.

Filter protection:

The filter protection uses a first-order inertia filter, which is a commonly used filter in control systems. Its output is exponentially close to the input.

First-order inertial filters are low-pass filters used to reduce high-frequency noise components in process measurement signals.

Filter formula: y(i)=K1*x(i)+K2*y(i-1), where K1=Ts/(Ts+TF), K2=1-K1; where y(i) is The current display value; x(i) is the current sampling value; y(i-1) is the last display value; Ts is the sampling period; TF is the filtering time, and K1 is called the filtering time constant.

It can be known from the formula that setting the filter time helps to improve the smoothness of the signal, and the longer the filter time, the smaller the impact of the current sampling value on the displayed value, and the smoother the curve.

These filters are often used on flow measurement signals because these signals tend to generate a lot of noise.

Normally, the filtering time is about (1.0~2.0) seconds for the pressure and flow signals, and the temperature signal is relatively stable. When not filtering, please set the filtering time to 0.

When it is greater than or equal to the set value ②, it is considered that unstable factors such as large fluctuations have occurred. First, an alarm will be given that the deviation rate is too fast, prompting the operator to pay attention and deal with it.

At the same time, an instruction is output to the automatic adjustment control program to switch the adjustment control from automatic mode to manual mode to prevent the adjustment valve from experiencing drastic fluctuations following the collected flow rate.

The present invention comprehensively analyzes and detects data by taking a variety of measures, and carries out optimization and protection measures for various abnormal situations that may occur, ensuring safe and reliable operation of automatic adjustment control of pipeline flow.

The technical solution of the present invention is not limited to the above-mentioned specific embodiments. Without departing from the scope and spirit of the illustrated embodiments, many modifications and changes will be obvious to those of ordinary skill in the art. Within the spirit and principles of the present invention, any technical modifications made fall within the protection scope of the present invention.

Claims (6)

1. A protection system for automatically adjusting and controlling pipeline flow is characterized in that: the device comprises a pipeline, a flowmeter and a regulating valve, wherein the flowmeter is arranged on the pipeline and used for collecting medium flow data in the pipeline, the regulating valve is used for regulating the medium flow in the pipeline, the device further comprises a main controller, an analog input module and an analog output module, the main controller is used for controlling and regulating the medium flow in the pipeline, the collected data of the flowmeter are transmitted to the main controller through the analog input module, the main controller performs comparison operation on the collected data, and the analog output module outputs a control signal to the regulating valve to execute regulation control on the medium flow in the pipeline.

2. The protection system for automatic pipe flow regulation control of claim 1, wherein: the main controller adopts a DCS system of ECS-700, and is internally provided with a data quality judgment protection, deviation rate change protection, data filtering protection and abnormality alarm function program for controlling and protecting the flow regulation process.

3. The protection system for automatic pipe flow regulation control of claim 1, wherein: the main controller is internally provided with a regulator functional block, so that the manual and automatic regulating function of the regulating valve can be switched.

4. The protection system for automatic pipe flow regulation control of claim 1, wherein: the flowmeter performs data transmission through an analog input signal of 4-20 mA and an analog input module.

5. The protection system for automatic pipe flow regulation control of claim 1, wherein: the analog output module controls the action of the regulating valve through an analog output signal of 4-20 mA.

6. A protection method for automatic regulation and control of pipeline flow, characterized in that the protection method is based on the protection system for automatic regulation and control of pipeline flow according to any one of claims 1-5, and specifically comprises the following steps:

s1, installing a deviation rate change protection program, a data quality judgment protection program and a data filtering protection program for a main controller, and setting a flow data threshold;

s2, the flowmeter collects medium flow data in the pipeline, and the medium flow data are transmitted to the main controller through the analog input module in an analog input signal of 4-20 mA;

s3, the DCS of the main controller calculates and compares the acquired data; when the collected data exceeds the upper and lower limit ranges of the threshold, judging that the data is abnormal, and giving an alarm; meanwhile, an instruction is sent to enable the main controller to be switched from an automatic mode to a manual mode, so that the regulating valve is prevented from following the abnormal overrun flow to perform false actions;

and S4, when the acquired data is within the threshold range, judging that the data is normal, wherein the main controller is in an automatic control mode, and controlling the action of the regulating valve by the main controller according to an analog output signal of 4-20 mA so as to automatically regulate the medium flow in the pipeline.