CN215369958U

CN215369958U - Redundant servo control system of steam turbine valve

Info

Publication number: CN215369958U
Application number: CN202120524828.2U
Authority: CN
Inventors: 刘文军; 高连达; 端木昭勇; 李群; 于龙; 曲博; 胡庆宇; 张秋喜; 李国江; 苏德; 侯建华; 李宝华; 赵刚
Original assignee: Manzhouli Dalai Lake Thermal Power Co ltd
Current assignee: Manzhouli Dalai Lake Thermal Power Co ltd
Priority date: 2021-03-12
Filing date: 2021-03-12
Publication date: 2021-12-31
Anticipated expiration: 2031-03-12

Abstract

The embodiment of the present utility model provides a control system for the redundant servo of steam turbine gate adjustment, including: a first servo module, a second servo module, a main controller, a backup controller, a first LVDT feedback loop, and a second LVDT feedback loop circuit, electro-hydraulic converter, oil motor; the main controller is connected with the first servo module, the backup controller is connected with the second servo module, the first servo module, the second servo module The servo modules are all connected in parallel to the electro-hydraulic converter, and the electro-hydraulic converter is connected to the oil motor; the first LVDT feedback loop is connected to the first servo module, and the second LVDT feedback loop The loop is connected to the second servo module, and the first LVDT feedback loop and the second LVDT feedback loop are both connected to the oil motor.

Description

Redundant servo control system of steam turbine valve

Technical Field

The utility model relates to the technical field of steam turbines, in particular to a control system for redundant servo of a steam turbine governor.

Background

The digital electro-hydraulic control system (DEH) of the unit turbine adopts a Symphony system produced by Beijing ABB belie engineering Limited, and the control module adopts an IMHSS13 hydraulic servo module. The development of the steam turbine control system is experienced by a mechanical hydraulic speed regulation system, a full hydraulic speed regulation system, an analog electro-hydraulic speed regulation system, an electro-hydraulic concurrent speed regulation system and a digital electro-hydraulic speed regulation system DEH which is generally adopted at present. The DEH control system adopts a digital computer as a controller, and the electric signal controls the oil pressure of high-pressure fire-resistant oil through an electro-hydraulic converter to drive the servomotor, so that the high-pressure main throttle valve and the medium-pressure main throttle valve are opened and closed, and the rotating speed and the load of the steam turbine are controlled. Reliable operation of the DEH system is the basis for ensuring stable operation of the unit, a redundant controller is basically adopted for most DEH control systems, and a redundant IO bus ensures reliable operation of the system.

But single-mode control is still used for the servo module controlling the valve. When the servo module has problems, the valve is easily opened or closed by mistake, the stable operation of the unit is affected, and even forced shutdown is caused.

SUMMERY OF THE UTILITY MODEL

The utility model provides a redundant servo control system for a steam turbine governor valve, and aims to solve the problem that the stable operation of a unit is influenced because the false opening and the false closing of the valve are easily caused when the existing servo module has problems. In order to achieve the purpose, the utility model adopts the following technical scheme:

a control system for redundant servo of a steam turbine governor comprising: the system comprises a first servo module, a second servo module, a main controller, a first LVDT feedback loop, a second LVDT feedback loop, an electro-hydraulic converter and an oil motor;

the first servo module and the second servo module are connected to the main controller, the first servo module and the second servo module are connected to the electro-hydraulic converter in parallel, and the electro-hydraulic converter is connected with the servomotor;

the first LVDT feedback loop is connected with the first servo module, the second LVDT feedback loop is connected with the second servo module, and the first LVDT feedback loop and the second LVDT feedback loop are both connected to the servomotor.

Furthermore, a pure proportional control mode is adopted between the first servo module and the second servo module.

Further, the first servo module and the second servo module are both of a type HSS 13.

Further, the first servo module and the second servo module are arranged in the cage.

Compared with the prior art, the utility model has the following advantages;

according to the control system for the redundant servo of the steam turbine valve regulator, the first servo module, the second servo module, the main controller, the first LVDT feedback loop and the second LVDT feedback loop are arranged, so that the risk of machine set shutdown caused by the problem of a single servo module is reduced, and the safety, the stability and the reliability of the machine set are improved. Thereby reducing the potential economic loss of the power plant.

In addition to the technical problems addressed by the present invention, the technical features constituting the technical solutions, and the advantageous effects brought by the technical features of the technical solutions described above, other technical problems that the present invention can solve, other technical features included in the technical solutions, and advantageous effects brought by the technical features will be described in further detail in the detailed description.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below.

FIG. 1 is a schematic connection diagram of a control system for redundant servo of a steam turbine governor according to an embodiment of the present invention;

FIG. 2 is a control schematic diagram of a control system for redundant servo of a steam turbine governor according to an embodiment of the present invention;

FIG. 3 is a control schematic of a single servo module;

fig. 4 is a control schematic of a single LVDT feedback loop.

Reference numerals:

1. a main controller; 2. a controller; 3. a first servo module; 4. a second servo module; 5. an electro-hydraulic converter; 6. an oil-operated machine; 7. a second LVDT feedback loop; 8. a first LVDT feedback loop.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below. It is to be understood that the described embodiments are merely a few embodiments of the utility model, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1 to 4, an embodiment of the present invention provides a control system for redundant servo of a steam turbine governor, including: the system comprises a first servo module 3, a second servo module 4, a main controller 1, a controller 2, a first LVDT feedback loop 8, a second LVDT feedback loop 7, an electro-hydraulic converter 5 and an oil motor 6;

as shown in fig. 1 and 2, the first servo module 3 and the second servo module 4 are both connected to the main controller 1, the first servo module 3 and the second servo module 4 are both connected to the controller 2, the first servo module 3 and the second servo module 4 are both connected to an electro-hydraulic converter 5, and the electro-hydraulic converter 5 is connected to the servomotor 6 to open or close the servomotor;

the first LVDT feedback loop 8 is connected with the first servo module 3, the second LVDT feedback loop 7 is connected with the second servo module 4, and the first LVDT feedback loop 8 and the second LVDT feedback loop 7 are both connected with the servomotor 6.

Specifically, the first servo module 3 and the second servo module 4 adopt a pure proportional control mode. The control of proportional integral is changed into the control of pure proportion, and the control mode of pure proportion is as follows: the controller's output signal c (t) can be proportional to its input signal epsilon (t); expressed mathematically, i.e.: c (t) kp epsilon (t). In the formula, kp is a proportionality coefficient; and a pure proportion control mode is arranged, so that mutual interference of the output instructions of the first servo module 3 and the second servo module 4 is eliminated.

In particular, the first servo module 3 and the second servo module 4 are each of the type HSS 13. The first servo module 3 and the second servo module 4 are both arranged in a cage.

It should be noted that the servo module and LVDT feedback loop are prior art. A unit turbine digital electro-hydraulic control system (DEH) can be referred to and a Symphony system produced by Beijing ABB belie engineering Co., Ltd; the control schematic diagram of the servo module is shown in FIG. 3, and the control schematic diagram of the LVDT feedback loop is shown in FIG. 4. In the application, a servo module and an LVDT feedback loop are added on the basis of the original servo module and the original LVDT feedback loop; no improvement was made to the servo module and LVDT feedback loop itself. And redundant coils of the LVDT feedback loop and the electro-hydraulic converter 5 form a fully redundant servo control system. The first servo module 3 and the second servo module are logically connected to the electro-hydraulic converter 5 through an AND gate to drive the electro-hydraulic converter 5.

It should be noted that the redundant controller includes a main controller 1 and a slave controller 2, and only the main controller 1 works during normal operation; when the main controller 1 fails, the redundant controller is automatically switched into the backup controller 2, and simultaneously, the commands are transmitted to the first servo module 3 and the second servo module 4; wherein the automatic switching of the main controller 1 and the controller 2 is prior art in DCS systems.

In actual operation the modified design is as follows,

first, the address of the first servo module 3 is No. 17, and the address of the second servo module 4 is No. 7 to form a redundant servo module control electro-hydraulic converter 5. The main controller 1 is connected with the first servo module 3 and the second servo module 4 through an IO bus; the controller 2 is connected with the first servo module 3 and the second servo module 4 through an IO bus.

Second, the first servo module 3 and the second servo module 4 are connected to the terminal block through signal cables.

Thirdly, modifying FC55 function codes S2, S3 and S4 of the first servo module 3 and the second servo module 4;

s2 and S3 select the first LVDT feedback loop 8 and the output of the first servo module 3 according to actual conditions, the first servo output is 0V when the S4 is set as the LVDT error, and the output of the first servo module 3 can be cut off when the first servo module 3 has problems through the setting of S4, so that the first servo module 3 is prevented from causing interference; the electro-hydraulic converter 5 can also be controlled by a second servo module in this case. Meanwhile, the servo module triggers an output inhibition function under certain conditions, such as timeout of a watchdog caused by mechanical failure of the module D or A error, and the servo module resets an output command to zero at the moment, and in this case, the other redundant module controls normal opening and closing of a valve.

Fourthly, the manual tracking logic is modified, when the first servo module 3 is off-line and is switched to the manual mode, the second servo module 4 also needs to track the instruction read-back value of the current first servo module, so that the first servo module 3 can be switched back to be automatic without disturbance after being recovered to be normal, and the electro-hydraulic converter 5 cannot generate disturbance.

The working principle is as follows:

the main controller 1 outputs an instruction to the first servo module 3 or the controller 2 to output an instruction to the second servo module, and then the instruction is compared with a position feedback instruction of the servomotor 6 of the first LVDT feedback loop 8 or the second LVDT feedback loop 7 respectively, and then the instruction is transmitted to the electrohydraulic converter 5, so that the opening degree of a valve core of the electrohydraulic converter 5 is changed, hydraulic oil in an oil cylinder of the servomotor 6 is changed, and the valve core of the servomotor 6 is moved to the position where the instruction is located; meanwhile, the misoperation of the servomotor caused by the fact that the output instruction is 0 due to the fact that the first servo module or the second servo module breaks down is avoided. And also facilitates on-line replacement of a faulty servo module.

Claims

1. a control system of a steam turbine door-adjusting redundant servo, is characterized in that, comprising: the first servo module, the second servo module, the main controller, the standby controller, the first LVDT feedback loop, the second LVDT feedback loop , Electro-hydraulic converter, oil motor;

The first servo module and the second servo module are both connected to the main controller, the first servo module and the second servo module are both connected to the standby controller, and the first servo module and the second servo module are both connected to the standby controller. The servo module and the second servo module are both connected to the electro-hydraulic converter, and the electro-hydraulic converter is connected to the oil motor;

The first LVDT feedback loop is connected to the first servo module, the first LVDT feedback loop is connected to the oil motor; the second LVDT feedback loop is connected to the second servo module, The second LVDT feedback loop is connected to the oil motor.

2 . The control system of a steam turbine gate-adjusting redundant servo according to claim 1 , wherein the first servo module and the second servo module adopt a pure proportional control mode. 3 .

3 . The control system of a steam turbine gate-adjusting redundant servo according to claim 1 , wherein the models of the first servo module and the second servo module are both HSS13. 4 .

4 . The control system for the redundant servo of steam turbine gate adjustment according to claim 1 , further comprising a machine cage, wherein the first servo module and the second servo module are both arranged in the machine cage. 5 .