Function of turbine brake cylinder

The first part is 1. The definition of hanging brake is to make the rotary vane pump move from the lower support point to the upper support point according to the action of steam pressure before the turbine generator is started, so as to establish steam pressure and realize the related work of the turbine generator in the future. 2. After the destination is locked, steam pressure can be generated in the lower cavity of each steam valve hydraulic cylinder, and a part of DEH electronic computer can operate a part of hydraulic actuators, and then the hydraulic actuators can operate the opening of each steam valve, thus increasing the steam quantity and finally controlling the speed ratio and load of the turbine generator. 3. Brake hanging mode The brake hanging mode is divided into remote (DEH) brake hanging and nearby (engine) brake hanging: 4. The whole process of brake hanging 5. The basic principle of hanging brake 1) The oil provided by the steam pressure of the hydraulic cylinder under the steam valve oil motor is transported to the lower cavity of the hydraulic cylinder through the hydraulic valve (green line in the figure). If you want to build a steam pressure unloading valve in the lower cavity of the hydraulic cylinder, you must close the lower cavity of the hydraulic cylinder to the pressurized oil return channel (bottom line in the figure). The interaction force of steam pressure (total wind oil) at the upper end of the rotary vane pump plus spring force will exceed the interaction force of high pressure oil at the lower end of the rotary vane pump, and the cup-shaped rotary vane pump will press on the base, so the accelerator pedal similar to the pressurized oil return of the hydraulic cylinder will be closed, and the steam pressure of high pressure oil in the lower cavity of the piston of the hydraulic cylinder will be generated. Therefore, emergency total wind oil will be produced. 3) The generation of emergency total wind oil is controlled by AST relay and pneumatic butterfly valve. Only when AST relay and pneumatic butterfly valve are closed can emergency total wind oil be created, which is actually ETS calibration and low-pressure safety personnel oil calibration. Therefore, hanging the brake of the generator set is a secondary calibration process. 6, ETS calibration -AST relay power off: 1)AST relay principle The working steps of AST solenoid valve, AST relay is energized, the relay pushes the valve core to sink, and the HP oil discharge channel provided by high pressure is closed (marked with light yellow). The pressure in the X chamber increases, which provides oil working pressure for high pressure, gets rid of the tension of the torsion spring 1 and pushes the piston rod. When AST relay trips, the solenoid valve core shifts under the pulling force of the spring plate 2, which opens the HP oil discharge channel provided by high pressure, and the pressure in the X cavity decreases, so it is impossible to get rid of the pulling force of the torsion spring 1 The piston rod deviates under the action of spring tension, which opens the oil discharge safety channel of AST emergency main air oil, and the AST emergency main air oil is overpressure. The actual operation of ETS calibration is to create the oil and steam pressure of AST emergency total air. According to the principle of AST relay, the actual operation of ETS calibration is to energize AST relay. 7. Check of low-pressure safety oil-close pneumatic butterfly valve: 1) Principle of pneumatic butterfly valve When low-pressure safety oil is produced and the steam pressure exceeds the spring force, the piston rod sinks to close the gate valve and block the total wind oil of EH disaster, that is, check of low-pressure safety oil of steam turbine; When the steam pressure of the pit is lower than the spring force, the piston rod pushes the gate valve to open, unloading the EH dangerous main air oil, and the unit trips. Therefore, if you want to close the pneumatic butterfly valve, you must make low-pressure safety personnel oil. 2) Calibrating low-pressure safety oil If we want to make low-pressure safety oil, we only need to move the rotary vane pump to the left and block the oil drain. There are two main ways to make the rotary vane pump move to the left: one is to turn the rocker arm to the nearby "calibration" position by human factors, and the other is to click the "brake arm" button at DEH point on the CRT in the control room to turn on the four-way solenoid valve, and the remote controller calibrates the sinking of the oil cylinder to make the rocker arm to the "calibration" position. There are two kinds of orifice plates on the drawing, and their functions are as follows: orifice plate 1 Function: When oil is discharged from the oil outlet of rotary vane pump, it will not affect the lubricating oil system of large POS and ensure good lubrication of bearings. The function of orifice plate 2: the oil discharge is small, and it is not easy to stop during refueling experiment. The second part is the whole process of generating set creating safe steam pressure. Only when the safe steam pressure is established can the steam pressure at the top of each oil motor be established (if the brake is not hung, the oil inlet at the bottom of the oil motor will get rid of the torsion spring of the unloading valve and leak from the working pressure oil inlet pipe), and then each oil motor can be opened. Generally speaking, the hanging brake is divided into two types, which are indispensable: one is the hanging brake of the generator set, which is characterized by the high pressure at the upper end of the pneumatic butterfly valve, which should generally be greater than 0.4-0.5 MPa. This working pressure varies according to the generator set, but operators are usually worried about tripping, so they all raise this working pressure to 0.7-0.8 MPa, and the other is the hanging brake of electrical equipment. That is, the telecommunication network is used to command OPC and AST valves to close. Generally, AST valves are powered off and OPC valves jump off. If there is a pressure AST and OPC barometer on the emergency main wind field effect tube, we can decide whether the electrical equipment is locked by the working pressure, or you can try it on the AST valve with a small wire. If it is magnetic, it can also indicate that a part of the electrical equipment is locked. Coherent attitude after braking suspension-ast relay is closed before braking suspension, opc relay is closed, but pneumatic butterfly valve is opened. Ast main pipe has two kinds of oil drain holes, one is ast relay, the other is pneumatic butterfly valve, so ast main pipe overpressure, opc main pipe steam pressure is zero. After the brake is hung, check the emergency main fan, steam pressure is generated at the upper end of the pneumatic butterfly valve, and the pneumatic butterfly valve is closed. Ast mother pipe establishes steam pressure, blocks the high-efficiency unloading valve of common high and medium pressure main valve oil motive, closes the unloading valve, blocks the oil drain hole of high pressure main valve oil motive, and opc mother pipe establishes steam pressure, blocks the oil drain hole of common high and medium pressure regulating valve high-efficiency unloading valve, closes the unloading valve and blocks the oil drain hole of common high and medium pressure regulating valve oil motive. There is no servo valve in the high-pressure main valve after the brake is hung, eh. In other words, the safety oil has been discharged and all steam valves have been completely closed. There are two kinds of braking, the nearest braking and vehicle-mounted braking. The posture of the nearby brake and the flying hammer is the same, both of which discharge the pressure oil at the upper end of the pneumatic butterfly valve, indicating that there is no steam pressure on the pneumatic butterfly valve, while the vehicle-mounted brake discharges AST steam pressure. Both braking methods use turbine tripping. After the brake is turned on, the continuous attitude shutdown data signal is sent to the main air relay and ast solenoid valve. The main air relay is turned on, the emergency main fan rotor exhausts air, the oil drain hole of the pneumatic butterfly valve is opened, and the pneumatic butterfly valve is opened, resulting in overpressure of the ast mother pipe. At the same time, ast relay will be turned on, resulting in overpressure of ast main pipe, thus completing two-way maintenance. Ast mother pipe overpressure will also lead to the opening of the high-efficiency unloading valve of the common high and medium pressure main valve (the steam pressure in the lower cavity of the common high and medium pressure main valve is lost and the common high and medium pressure main valve is closed), and it will also lead to the overpressure of opc mother pipe, the high-efficiency unloading valve of the common high and medium pressure regulating valve is opened and the common high and medium pressure regulating valve is closed. For the 600MW generator set of Harbin Automobile Co., Ltd., the whole braking process is as follows: 1, the hydrogen sealed gasoline pump and EH oil pump are running, ETS is calibrated first, and AST relay is turned on and off. 2, DEH point turbine generator brake, calibration of emergency total vane pump, create brake steam pressure and low pressure safety oil, close the pneumatic butterfly valve, create ASY steam pressure, open the high pressure automatic main valve.