CN-116906131-B - Online adjustment method for AP value of servo valve of steam turbine regulating valve

CN116906131BCN 116906131 BCN116906131 BCN 116906131BCN-116906131-B

Abstract

The invention relates to an on-line adjustment method for an AP value of a servo valve of a steam turbine, which comprises a valve body, a valve sleeve arranged on the inner wall surface of the valve body, a first adjusting piece and a second adjusting piece which are respectively locked at two ends of the valve body and can be abutted against the two ends of the valve sleeve, wherein the on-line adjustment is carried out according to the following steps that S1, the current AP value of the servo valve is compared with a standard AP value, when the current AP value is smaller than the standard AP value, the step S2 is executed, when the current AP value is larger than the standard AP value, the steps S3 and S2 are executed, the first adjusting piece is rotated to be separated from the valve sleeve, then the second adjusting piece is rotated to push the valve sleeve to move to be abutted against the valve sleeve, then the step S4 and S3 are jumped to, the second adjusting piece is rotated to be separated from the valve sleeve, and then the valve sleeve is pushed to move until the valve sleeve is abutted against the second adjusting piece to be reduced, and the current AP value of the servo valve is reduced, and the on-line adjustment is ended. The method can eliminate foreign matters and risk of oil leakage.

Inventors

LI CHUNGUANG
HUANG XIONGWEI
FU CHAOYANG
LI FEIHAN
TUO QINCAI
CHEN ZHAO
HE WEI
CHEN PENG
Yao Yazhou
LUO LEI
QIN YELIN
LI XIAOHUI
ZHU YINGJIE

Assignees

中广核核电运营有限公司

Dates

Publication Date: 20260505
Application Date: 20230625

Claims (6)

1. The on-line adjustment method for the AP value of the servo valve of the steam turbine adjusting valve comprises a valve body (1), a valve sleeve (3) arranged on the inner wall surface of the valve body (1), a first adjusting piece (4) and a second adjusting piece (5) which are locked at two ends of the valve body (1) respectively and can be abutted against two ends of the valve sleeve (3), and is characterized by comprising the following steps of: s1, comparing a current AP value of the servo valve with a standard AP value, and executing a step S2 when the current AP value is smaller than the standard AP value, and executing a step S3 when the current AP value is larger than the standard AP value; S2, rotating the first adjusting piece (4) to separate the valve sleeve (3), then rotating the second adjusting piece (5) to push the valve sleeve (3) to move to abut against the first adjusting piece (4) so as to increase the current AP value of the servo valve, and then jumping to the step S4; S3, rotating the second adjusting piece (5) to be separated from the valve sleeve (3), and then rotating the first adjusting piece (4) to push the valve sleeve (3) to move until the valve sleeve is abutted against the second adjusting piece (5) so as to reduce the current AP value of the servo valve; s4, the servo valve is operated once to obtain a new current AP value, and the current AP value is compared with a preset range; When the current AP value exceeds the preset range, jumping to the step S1 to repeat the adjustment once; ending the online adjustment when the current AP value is within the preset range; When the current AP value is within the preset range, a return-to-zero test is carried out on the servo valve, and the servo valve is confirmed to be gradually closed when no current is input; When the first adjusting piece (4) and the second adjusting piece (5) are adjusted by 10 degrees, corresponding to the change of the AP value 1, namely, when the valve sleeve (3) is driven to move towards the first adjusting piece (4), the AP value is increased, the valve sleeve (3) is driven to move towards the second adjusting piece (5), and the AP value is reduced, so that bidirectional correction and adjustment are facilitated; When the absolute value of the difference between the AP value and the preset range is larger than 3, the first regulating piece (4) or the second regulating piece (5) is regulated for 20-30 degrees each time; when the absolute value of the difference between the AP value and the preset range is less than or equal to 3, the first regulating piece (4) or the second regulating piece (5) is regulated by only 10 degrees at a time.
2. The online adjustment method of the servo valve AP value of the steam turbine adjusting valve according to claim 1, wherein in the step S2 and the step S3, the angle of each rotation of the first adjusting member (4) is not more than 30 °, and the angle of each rotation of the second adjusting member (5) is not more than 30 °.
3. The online adjustment method of the servo valve AP value of the steam turbine adjusting valve according to claim 2, wherein the sum of the angles of the multiple rotations of the first adjusting member (4) in the same direction is not more than 360 °, and the sum of the angles of the multiple rotations of the second adjusting member (5) in the same direction is not more than 360 °.
4. The online adjustment method of the servo valve AP value of the steam turbine adjusting valve according to claim 2, wherein the first adjusting member (4) and the second adjusting member (5) are rotated by the same angle each time.
5. The method according to any one of claims 1-4, characterized in that in step S2, after the valve sleeve (3) has been pressed against the first adjusting member (4) or after the valve sleeve (3) has been pressed against the second adjusting member (5) in step S3, a tightening torque of 2.5n·m is used for the first adjusting member (4) and the second adjusting member (5).
6. The online adjustment method for the servo valve AP value of the steam turbine adjusting valve according to any one of claims 1 to 3, further comprising, before the step S1: confirming that the servo valve and a driving mechanism and a valve body matched with the servo valve have no faults; And confirming that the servo valve is not input, wherein the servo valve comprises the step of closing the driving mechanism, stopping the oil pump of the corresponding GFR system and releasing pressure, and the step of disconnecting the aviation plug.

Description

Online adjustment method for AP value of servo valve of steam turbine regulating valve Technical Field The invention relates to the field of nuclear power, in particular to an online adjustment method for an AP value of a steam turbine regulating valve. Background In order to eliminate control command deviation and realize 'deviation-free' adjustment, a control system for adjusting a valve of a nuclear power 1000MW half-speed machine introduces a servo valve AP value into valve control logic. When the AP value is acquired, the valve is required to be positioned at a certain opening stable position, and a relatively stable comprehensive calculated AP value can be output in the control system. In the servo valve, there is also a zero offset value, and the AP value is different from the zero offset value of the servo valve. The "zero bias" refers to a characteristic that the output flow is not zero when the input current is zero due to the influence of factors such as the structural size, electromagnetic performance, hydraulic characteristic, assembly and the like of elements constituting the valve, and the corresponding input current is a zero bias value of the servo valve when the output flow is zero. The zero offset value of the servo valve is the control characteristic of the servo valve, when the input current value exceeds the zero offset value of the servo valve, the valve core of the servo valve is offset to enable the driving mechanism to feed oil, when the input current value is smaller than the zero offset value, the valve core of the servo valve is offset to the negative direction, the driving mechanism is enabled to discharge oil to an oil return pipeline, and the main influencing factor of the zero offset value is derived from the servo valve. The servo valve AP value is the comprehensive embodiment of the servo valve, a driving mechanism, a valve body and a control system, when the valve is regulated to be stable, stable deviation exists between the actual opening and the instruction, and the stable deviation is the sum of the servo valve AP value, the dithering current and the control instruction deviation. The servo valve is an electro-hydraulic switching valve with precise control, the zero offset value of the servo valve is not suitable to be adjusted to be too small or negative, when the zero offset value of the servo valve is too small or even negative, the adjusting system for adjusting the AP value is unstable, the servo valve can lose the protection function of ensuring that a driving mechanism is immediately closed under the condition of power failure, meanwhile, the zero offset value is not too large to be adjusted, the adjusting sensitivity of the adjusting system is reduced due to the fact that the zero offset value is too large to be adjusted, the AP value can reflect the stability of a valve and the adjusting system of the valve from the side, and the AP value is generally adjusted to be a standard value before a unit is started. The influence factors of the AP value of the servo valve are very many, all factors influencing the deviation of the opening degree of the valve can influence the AP value of the servo valve, including the leakage amount of the servo valve, the blockage of a nozzle, the resistance of a slide valve, the magnetic force and the resistance of a torque motor, the leakage amount of a driving mechanism, the friction force, the spring force and the buffer stroke of the driving mechanism, the friction force and the stroke of a valve body, and the comprehensive parameters of all clamping pieces of a control system, namely all factors influencing the current when the valve is opened, such as the leakage amount of the driving structure, the movement resistance, the blockage of a hydraulic system, the resistance, the capacitance and the like, influence the AP value of the servo valve. Because the factors which are most easily changed on site are various factors contained in the servo valve, and the servo valve is a servo valve which is subjected to maintenance of a replacement return factory, the various factors of the servo valve are regarded as an integral factor, and each part of the valve, the driving mechanism and the control system are regarded as integral factors of the valve, different AP values can be generated by the same servo valve and different valve bodies, and different AP values can be generated by the same valve body and different servo valves. The current method for changing the AP value is to replace a servo valve blind test, and after each AP value test, the servo valve is replaced if the AP value does not meet the requirement until the AP value is replaced to the servo valve with the AP value within the standard range, and the method has the following defects: Firstly, the single replacement time is long, the valve oil system is required to be isolated for each replacement, and the replacement is about 10H once, so that the operation of machine eq