CN118226246A - State maintenance system and method suitable for AST electromagnetic valve protection loop - Google Patents

Abstract

The invention discloses a state maintenance system and a state maintenance method suitable for an AST electromagnetic valve protection loop, comprising a DCS system, wherein the DCS system is controlled by a plurality of AST electromagnetic valves, and a plurality of closed loops are formed between the plurality of AST electromagnetic valves and the DCS system; the closed loop is provided with a current detection device which is electrically connected with the DCS system to form a current detection loop; the surfaces of the AST electromagnetic valves are provided with temperature sensing devices, and the temperature sensing devices are electrically connected with the DCS system to form a temperature detection loop. By comparing the current of the AST electromagnetic valve with the current of the temperature judgment of the AST electromagnetic valve, the abnormal AST electromagnetic valve is judged, false alarm is not frequently generated, the alarm threshold value of the current deviation is reduced, and the current deviation of the electromagnetic valve is accurately judged in advance. The technical problem that an AST electromagnetic valve cannot discover abnormal states of the AST electromagnetic valve in time in advance due to regular overhaul in the prior art is solved.

Description

State maintenance system and method suitable for AST electromagnetic valve protection loop

Technical Field

The invention belongs to the technical field of AST state monitoring, and particularly relates to a state maintenance system suitable for an AST electromagnetic valve protection circuit and a state maintenance method suitable for the AST electromagnetic valve protection circuit.

Background

All turbines of the thermal power plant are provided with ETS system protection turbine main equipment, and the main executive component of the emergency shutdown consists of a critical interruption control block with 4 AST electromagnetic valves and 2 overspeed protection control valves, and the like. The emergency shutdown of the ETS system is achieved by controlling the oil pressure through the solenoid valve assembly. AST solenoid valve assemblies are the most important components in the system. AST solenoid valve is electrified for a long time, and the operating voltage is 220VAC, and the temperature is higher and sometimes higher than 100 ℃ during electrified operation. The electromagnetic valve coil is aged due to high temperature, the aging can further increase the temperature, the situation that a plurality of electromagnetic valve coils are burnt to cause false tripping of a starting turbine unit can occur in a short time, and the unit is not scheduled to be shut down due to AST electromagnetic valve faults every year, so that the stability of a power grid is very unfavorable. The AST electromagnetic valve of the general thermal power plant adopts manual temperature measurement, periodically tests whether the electromagnetic valve normally acts, and periodically changes the control measure of the electromagnetic valve. In operation, the method is a treatment method for immediately replacing the solenoid valve coil on line after the solenoid valve coil is found out of order, and if the solenoid valve coil is out of order, the solenoid valve coil can be stopped. Namely, the AST solenoid valve is subjected to periodic test, periodic maintenance and fault maintenance modes.

The working state of the existing AST electromagnetic valve cannot be monitored and early-warned on line, and the output condition cannot be monitored; the aging state cannot be monitored on line, namely the insulation of the coil or the loop is reduced, and the contact resistance is increased and cannot be found in time; the abnormal valve core or the aging state of the sealing element of the existing AST electromagnetic valve can not be found in advance, and only the test period and the replacement period can be quickened or the replacement can be forced to stop after the fault; the existing AST electromagnetic valve control loop is complex, multiple nodes such as a manual switching-on button are connected in series, and any node contact failure can cause the power-off action of the AST electromagnetic valve, so that no online monitoring means is provided for the contact resistance condition of each node. Even if the current monitoring alarm is designed in the prior art, the control of the power supply voltage and the power supply frequency is not considered, and the current monitoring alarm is inaccurate and the data is not well utilized. Even if the existing temperature monitoring alarm is designed, the temperature of the working environment of the AST electromagnetic valve is not considered to change from about 5 ℃ to about 50 ℃ in four seasons, so that the temperature monitoring alarm is inaccurate.

Disclosure of Invention

The first object of the present invention is to provide a status maintenance system suitable for an AST electromagnetic valve protection circuit, which solves the technical problem that an AST electromagnetic valve cannot discover an abnormal status of the AST electromagnetic valve in time due to regular maintenance in the prior art.

The second object of the present invention is to provide a state maintenance method suitable for an AST electromagnetic valve protection circuit, which solves the technical problem that the working state of an AST electromagnetic valve cannot be monitored on line in the prior art.

The first technical scheme adopted by the invention is that the state maintenance system suitable for an AST electromagnetic valve protection loop comprises a DCS system, wherein the DCS system is electrically connected with a plurality of AST electromagnetic valves, a plurality of closed loops are formed between the plurality of AST electromagnetic valves and the DCS system, and a power supply is arranged on the closed loops;

The closed loops are provided with current detection devices, and the current detection devices are electrically connected with the DCS system to form a current detection loop;

The surfaces of the AST electromagnetic valves are provided with temperature sensing devices, and the temperature sensing devices are electrically connected with the DCS system to form a temperature detection loop.

The first technical solution of the invention is also characterized in that,

The number of the AST electromagnetic valves is four, the number of the detection circuits is four, each detection circuit is provided with a current detection device, and the side wall of each AST electromagnetic valve is provided with a temperature sensing device.

The current detection device adopts a current transducer.

The temperature sensing device adopts a patch thermal resistor.

The DCS system is connected with a single-loop flash alarm.

The second technical scheme adopted by the invention is that the state maintenance method suitable for the AST electromagnetic valve protection circuit is used, and the state maintenance system suitable for the AST electromagnetic valve protection circuit specifically comprises the following steps:

Step 1, respectively installing four current transmitters on a closed loop between four AST electromagnetic valves and a DCS system;

Step 2, arranging four patch thermal resistors on the side walls of the four AST electromagnetic valves respectively;

step 3, setting a power supply on the closed loop of the step 1 to electrify the AST electromagnetic valve;

step 4, the current transducer and the patch thermal resistor transmit the measured value signal to a DCS system;

Step 5, calculating an actual measurement ideal current value and an actual measurement ideal temperature value of the AST electromagnetic valve according to the numerical value measured in the step 4 by the DCS;

Step 6, the current transducer and the patch thermal resistor monitor the current and the temperature of the AST electromagnetic valve in real time, and judge whether the current and the temperature of the AST electromagnetic valve are abnormal or not by comparing the current and the temperature with the actual measurement ideal current value and the actual measurement ideal temperature value in the step 5;

Step 7, if the current and/or the temperature of the AST electromagnetic valve are abnormal, the DCS system sends a signal to the single-loop flash alarm instrument to control the single-loop flash alarm instrument to alarm;

if the current and/or the temperature of the AST electromagnetic valve are normal, returning to the step 6, and continuously monitoring the current and the temperature of the AST electromagnetic valve by the current transducer and the patch thermal resistor in real time.

The second technical proposal of the invention is also characterized in that,

The specific calculation method of the actually measured ideal current value and the actually measured ideal temperature value in the step 5 is as follows:

adding the values obtained by detecting the 4 AST electromagnetic valves in the same time period through a current transmitter, subtracting the maximum value and the minimum value, and obtaining one half of the values to obtain the actually measured ideal current value of each AST electromagnetic valve;

and adding the values detected by the patch thermal resistor in the same time period of the 4 AST electromagnetic valves, subtracting the maximum value and the minimum value, and obtaining one half of the values to obtain the actually measured ideal temperature value of each AST electromagnetic valve.

In the step 6, when the deviation between the current monitored by the current transducer and the actually measured ideal current value exceeds +/-5% of the rated current of the selected electromagnetic valve coil, the abnormality is determined;

And when the deviation between the temperature monitored by the patch thermal resistor and the actually measured ideal temperature value exceeds the temperature of the selected solenoid valve coil by +/-5 ℃, the abnormality is obtained.

The beneficial effects of the invention are as follows:

According to the invention, a plurality of AST electromagnetic valves are integrated on one DCS system in a lossless manner, a current detection device is arranged on a closed loop between each AST electromagnetic valve and the DCS system, a temperature sensing device is arranged on each AST electromagnetic valve, the current and the temperature of each AST electromagnetic valve are monitored in real time through the arrangement of the current detection device and the temperature sensing device, the abnormal AST electromagnetic valve is judged by comparing the current and the temperature of each AST electromagnetic valve through actual measurement ideal values, false alarm is not frequently generated, the alarm threshold value of current deviation can be reduced, the current deviation of the electromagnetic valve can be judged in advance, and the accurate and advanced judgment is realized.

Drawings

FIG. 1 is a schematic diagram of a state maintenance system of the present invention adapted for use with an AST solenoid valve protection circuit;

FIG. 2 is a schematic diagram of the current anomaly alarm logic for an AST solenoid valve in a status maintenance system for an AST solenoid valve protection circuit of the present invention;

FIG. 3 is a schematic diagram of a temperature anomaly alarm logic for an AST solenoid valve in a status maintenance system for an AST solenoid valve protection circuit according to the present invention;

FIG. 4 is a schematic diagram of a curve of normal start current and operating current lower than the actual measured ideal current of an AST solenoid valve in a state maintenance system suitable for an AST solenoid valve protection loop;

FIG. 5 is a schematic diagram of a state maintenance system for an AST solenoid valve protection circuit according to the present invention, wherein the starting current and the working current of an AST solenoid valve are both lower than the actual measured ideal current;

FIG. 6 is a schematic diagram of a state maintenance system for an AST solenoid valve protection circuit of the present invention in which both the start current and the operating current of an AST solenoid valve are higher than the actual measured ideal current;

fig. 7 is a schematic diagram of a curve of an operating temperature of an AST solenoid valve higher than an actual measured ideal temperature in a state maintenance system applied to an AST solenoid valve protection circuit according to the present invention.

In the figure, a DCS system, a first current transducer, a second current transducer, a first power supply, a first patch thermal resistor, a first AST electromagnetic valve, a second patch thermal resistor and a second patch thermal resistor are respectively arranged in the figure, wherein the first current transducer, the second current transducer, the first power supply, the first patch thermal resistor, the first AST electromagnetic valve, the second AST electromagnetic valve and the second patch thermal resistor are respectively arranged in the figure, the three-phase current sensor comprises a third current transmitter, a fourth current transmitter, a second power supply, a third patch thermal resistor, a third AST electromagnetic valve, a fourth AST electromagnetic valve and a fourth patch thermal resistor.

Detailed Description

The invention is further explained below with reference to the drawing and the specific embodiments.

Example 1

As shown in fig. 1, the state maintenance system suitable for an AST electromagnetic valve protection loop disclosed by the invention comprises a DCS system 1, wherein the DCS system 1 is electrically connected with a plurality of AST electromagnetic valves, a plurality of closed loops are formed between the plurality of AST electromagnetic valves and the DCS system 1, and a power supply is arranged on the closed loops;

the closed loops are provided with current detection devices, and the current detection devices are electrically connected with the DCS system 1 to form a current detection loop;

the surfaces of the AST electromagnetic valves are provided with temperature sensing devices, and the temperature sensing devices are electrically connected with the DCS system 1 to form a temperature detection loop.

In the actual use process, the lengths of the cables of the closed loops are the same, the closed loops of the AST electromagnetic valve are the same, whether a plurality of current signals are consistent or not can be monitored and judged in logic real time, if a certain current signal is inconsistent with other current signals, the abnormal condition is confirmed, no matter how the voltage and the frequency of a control power supply change, false alarm can not be frequently generated, the alarm threshold value of current deviation can be reduced, the abnormal AST electromagnetic valve body, AST electromagnetic valve coil and control loop can be accurately judged in advance through the electromagnetic valve current deviation as soon as possible, and state maintenance is timely arranged; the working environments of the AST electromagnetic valves are the same, whether the temperature signals are consistent or not can be logically monitored and judged in real time, if a certain temperature signal is inconsistent with other temperature signals, the problem is definitely caused, and no matter how the environment temperature changes in spring, summer, autumn and winter, the abnormal AST electromagnetic valve can be accurately judged in advance through the temperature of the coil of the AST electromagnetic valve, and state maintenance is timely arranged; the invention can monitor and discover abnormal conditions such as abnormal AST solenoid valve, AST solenoid valve coil and control loop bad contact in real time by judging the working current and working temperature of the AST solenoid valve and utilizing the current deviation and temperature deviation of a plurality of AST solenoid valves, and can judge whether the working state of the AST solenoid valve is normal in real time by integrating the AST solenoid valve, the current detection device and the temperature sensing device into the DCS system 1. The original AST electromagnetic valve has no feedback signal, and normally the AST electromagnetic valve is considered to normally operate as long as the instruction is sent, current can be used as the feedback signal at present, and the normal operation of the AST electromagnetic valve can be confirmed when the instruction is sent and the current reaches a certain value, so that the actual situation of the AST electromagnetic valve can be truly reflected. The invention can be improved on the basis of not affecting the reliability of the original closed loop.

According to whether the working current and the temperature of the AST electromagnetic valve are in a proper range, the abnormal conditions such as poor loop contact, insufficient valve core action, ageing of a sealing element, ageing of coil insulation, hidden problems caused by irregular process during overhauling and the like can be judged, and the abnormal deformation of the coil due to overlarge fastening moment can be judged. The temperature of the AST electromagnetic valve is monitored continuously in real time, the problems of uncertainty and periodic interval of manual periodic temperature measurement are avoided, and periodic maintenance and fault maintenance of the AST electromagnetic valve can be converted into state maintenance.

Example 2

Based on embodiment 1, the number of the AST electromagnetic valves in this embodiment is four, the number of the detection circuits is four, each detection circuit is provided with a current detection device, and the side wall of each AST electromagnetic valve is provided with a temperature sensing device.

In the present embodiment, 4 AST solenoid valves are used, namely, a first AST solenoid valve 6, a second AST solenoid valve 7, a third AST solenoid valve 13 and a fourth AST solenoid valve 14; namely 4 current sensing devices and 4 temperature sensing devices.

Further, the current detection device adopts a current transducer, and the temperature sensing device adopts a patch thermal resistor.

Correspondingly, the number of the closed loop, the current detection device and the temperature sensing device is four, and the current transducer can directly convert alternating current in the closed loop to direct current 4-20 mA constant current loop standard signals output according to the linear proportion and continuously convey the direct current 4-20 mA constant current loop standard signals to the DCS system;

PT100 is selected as the patch thermal resistor, the size is controlled to be one quarter of the area of a metal part at the side of the AST electromagnetic valve, the installation positions of the patch thermal resistor on all AST electromagnetic valves are consistent, the resistance value of the patch thermal resistor is 100 ohms when the PT100 is at 0 ℃, the resistance value of the patch thermal resistor can be increased at a nearly uniform speed along with the temperature, and abnormal electromagnetic valves can be accurately judged in advance regardless of the change of the ambient temperature in four seasons of spring, summer, autumn and winter, and timely state maintenance is arranged.

According to the working current and the wire diameter of an AST electromagnetic valve, a current transducer with a corresponding model is selected, and an alternating current transducer, a 0-1A range, an accuracy level 0.2, a 4-20mA output, a 24VDC power supply and a pore diameter of 4mm are selected corresponding to CCP 230D; 4-20mA output by the current transducer is connected to the DCS system. In this embodiment, the 4 current detecting devices are a first current transducer 2, a second current transducer 3, a third current transducer 9 and a fourth current transducer 10, respectively, and the 4 temperature sensing devices are a first patch thermal resistor 5, a second patch thermal resistor, a third patch thermal resistor 12 and a fourth patch thermal resistor 15, respectively.

Example 3

On the basis of the embodiment 1, a single-loop flash alarm instrument is connected with the DCS system.

When in use, the single-loop flash alarm is externally connected with an electric bell or sounder, and the out-of-limit alarm is realized through the control of the DCS system.

The invention also discloses a state maintenance method suitable for the AST electromagnetic valve protection circuit, which comprises the following steps:

Step 1, respectively installing four current transmitters on a closed loop between four AST electromagnetic valves and a DCS system;

Step 2, arranging four patch thermal resistors on the side walls of the four AST electromagnetic valves respectively;

step 3, setting a power supply on the closed loop of the step 1 to electrify the AST electromagnetic valve;

step 4, the current transducer and the patch thermal resistor transmit the measured value signal to a DCS system;

Step 5, calculating an actual measurement ideal current value and an actual measurement ideal temperature value of the AST electromagnetic valve according to the numerical value measured in the step 4 by the DCS;

The specific calculation method of the actually measured ideal current value and the actually measured ideal temperature value in the step 5 is as follows:

adding the values obtained by detecting the 4 AST electromagnetic valves in the same time period through a current transmitter, subtracting the maximum value and the minimum value, and obtaining one half of the values to obtain the actually measured ideal current value of each AST electromagnetic valve;

and adding the values detected by the patch thermal resistor in the same time period of the 4 AST electromagnetic valves, subtracting the maximum value and the minimum value, and obtaining one half of the values to obtain the actually measured ideal temperature value of each AST electromagnetic valve.

Step 6, the current transducer and the patch thermal resistor monitor the current and the temperature of the AST electromagnetic valve in real time, and judge whether the current and the temperature of the AST electromagnetic valve are abnormal or not by comparing the current and the temperature with the actual measurement ideal current value and the actual measurement ideal temperature value in the step 5;

In the step 6, when the deviation between the current monitored by the current transducer and the actually measured ideal current value exceeds +/-5% of the rated current of the selected electromagnetic valve coil, the abnormality is determined;

And when the deviation between the temperature monitored by the patch thermal resistor and the actually measured ideal temperature value exceeds the temperature of the selected solenoid valve coil by +/-5 ℃, the abnormality is obtained. Step 7, if the current and/or the temperature of the AST electromagnetic valve are abnormal, the DCS system sends a signal to the single-loop flash alarm instrument to control the single-loop flash alarm instrument to alarm;

if the current and/or the temperature of the AST electromagnetic valve are normal, returning to the step 6, and continuously monitoring the current and the temperature of the AST electromagnetic valve by the current transducer and the patch thermal resistor in real time.

Wherein, the steps 4-7 are shown in fig. 2 and 3.

As shown in fig. 4-7, in fig. 4, the starting current of a certain solenoid valve is normal, the working current is lower than the actually measured ideal current, and the solenoid valve is judged to be jammed and not in place. In fig. 5, the starting current and the working current of a certain solenoid valve are lower than the actual measurement ideal current, and the poor contact of the control loop is judged. In fig. 6, the solenoid valve coil is judged to be aged when the solenoid valve starting current and the operating current are higher than the actual ideal current. In fig. 7, the solenoid valve coil is judged to be aged when the operating temperature of a certain solenoid valve is higher than the actual ideal temperature.

Claims (8)

1. The state maintenance system suitable for the AST electromagnetic valve protection loop is characterized by comprising a DCS (1), wherein the DCS (1) is electrically connected with a plurality of AST electromagnetic valves, a plurality of closed loops are formed between the AST electromagnetic valves and the DCS (1), and a power supply is arranged on the closed loops;

The closed loops are provided with current detection devices, and the current detection devices are electrically connected with the DCS (1) to form a current detection loop;

the surfaces of the AST electromagnetic valves are provided with temperature sensing devices, and the temperature sensing devices are electrically connected with the DCS system (1) to form a temperature detection loop.

2. The state maintenance system applicable to an AST electromagnetic valve protection circuit according to claim 1, wherein the number of the AST electromagnetic valves is four, the number of the detection circuits is four, a current detection device is arranged on each detection circuit, and a temperature sensing device is arranged on the side wall of each AST electromagnetic valve.

3. The condition maintenance system for an AST solenoid valve protection circuit of claim 2, wherein the current sensing device employs a current transducer.

4. The condition maintenance system for an AST solenoid valve protection circuit of claim 2, wherein the temperature sensing device employs a patch thermal resistor.

5. The condition maintenance system for an AST solenoid valve protection circuit of claim 4, wherein the DCS system is connected with a single circuit flash alarm.

6. A method for status maintenance applicable to an AST solenoid valve protection circuit, using the status maintenance system applicable to an AST solenoid valve protection circuit according to claim 5, characterized by comprising the steps of:

Step 1, respectively installing four current transmitters on a closed loop between four AST electromagnetic valves and a DCS system;

Step 2, arranging four patch thermal resistors on the side walls of the four AST electromagnetic valves respectively;

Step 3, setting a power supply on the closed loop in the step 1 to electrify the AST electromagnetic valve;

step 4, the current transducer and the patch thermal resistor transmit the measured value signal to a DCS system;

Step 5, calculating an actual measurement ideal current value and an actual measurement ideal temperature value of the AST electromagnetic valve according to the numerical value measured in the step 4 by the DCS;

Step 6, the current transducer and the patch thermal resistor monitor the current and the temperature of the AST electromagnetic valve in real time, and judge whether the current and the temperature of the AST electromagnetic valve are abnormal or not by comparing the current value with the actual measurement ideal current value and the actual measurement ideal temperature value in the step 5;

Step 7, if the current and/or the temperature of the AST electromagnetic valve are abnormal, the DCS system sends a signal to the single-loop flash alarm instrument to control the single-loop flash alarm instrument to alarm;

if the current and/or the temperature of the AST electromagnetic valve are normal, returning to the step 6, and continuously monitoring the current and the temperature of the AST electromagnetic valve by the current transducer and the patch thermal resistor in real time.

7. The method for overhauling the state of the protection circuit of the AST electromagnetic valve according to claim 6, wherein the specific calculation method of the actually measured ideal current value and the actually measured ideal temperature value in the step 5 is as follows:

adding the values obtained by detecting the 4 AST electromagnetic valves in the same time period through a current transmitter, subtracting the maximum value and the minimum value, and obtaining one half of the values to obtain the actually measured ideal current value of each AST electromagnetic valve;

and adding the values detected by the patch thermal resistor in the same time period of the 4 AST electromagnetic valves, subtracting the maximum value and the minimum value, and obtaining one half of the values to obtain the actually measured ideal temperature value of each AST electromagnetic valve.

8. The method for overhauling the state of the protection circuit of the AST electromagnetic valve according to claim 6, wherein in the step 6, when the deviation between the current monitored by the current transmitter and the actually measured ideal current value exceeds +/-5% of the rated current of the selected electromagnetic valve coil, the abnormality is determined;

And when the deviation between the temperature monitored by the patch thermal resistor and the actually measured ideal temperature value exceeds the temperature of the selected solenoid valve coil by +/-5 ℃, the abnormality is obtained.