Control method for rapid door drop of large hydropower station

Abstract

The present invention relates to a method for controlling the rapid door drop of a large hydropower station. The method performs a logical OR operation on five door drop control signals to obtain an output signal for the rapid door of the large hydropower station to complete the door drop; the first door drop control signal is a rapid door drop button signal, a rapid door drop relay signal, or an emergency rapid door drop button signal of a simulated return screen; the second door drop control signal is a unit shutdown signal for a type of mechanical accident shutdown; the third door drop control signal is a rapid shutdown process start signal; the fourth door drop control signal is an emergency shutdown process start signal; and the fifth door drop control signal is a low oil pressure or low oil level signal of the hydraulic system of the unit speed regulator. The present invention greatly improves the reliability of the door drop protection action, eliminates the potential hidden dangers of the traditional single signal outlet or the mistaken drop of the rapid door due to signal jitter, and completely eliminates the risk hidden dangers of a single-point mistaken operation outlet, which can effectively prevent the occurrence of flooding accidents, major casualties, and damage to equipment and facilities.

Description

Technical Field

[0001] The invention belongs to the field of hydropower generation control, and in particular relates to a method for controlling the rapid door drop of a large hydropower station. Background Art

[0002] Currently, the automatic control systems of large hydroelectric generator sets are generally implemented using digital devices such as programmable logic controllers (PLCs) to form local control units. In the event of a large hydropower station unit shutdown, the guide vanes cannot be closed properly, the unit's stage II overspeed occurs, or the volute manhole door ruptures. To prevent major power safety incidents such as unit escape or plant flooding, the hydroelectric unit must be capable of emergency shutdown and emergency door drop. Plant flooding accidents are characterized by suddenness, rapid development, and severe harm, with extremely serious consequences, resulting in significant equipment damage and heavy casualties. In extreme circumstances, the rapid drop of hydroelectric unit doors is crucial as the last line of defense for safe production. It reliably cuts off the water flow and current, severing the hydroelectric unit's energy connection to the outside world, and ensuring the safe operation of the hydroelectric unit and the entire power station. Summary of the Invention

[0003] The purpose of the present invention is to address the above-mentioned problems and provide a method for controlling the rapid door dropping of a large hydropower station, thereby improving the reliability of the door dropping equipment of the hydropower unit in the event of a unit failure or accident, effectively reducing the risk of door dropping due to malfunction when the unit is in normal operation or standby, and avoiding accidents such as flooding of the plant due to signal refusal; achieving complete functions and being able to play a backup protection role, the emergency door dropping action of the unit is reliable, and can effectively avoid accidents such as unit escape and flooding of the plant, thereby ensuring the safe and stable operation of the power equipment.

[0004] The technical solution of the present invention is a door-drop control method for rapid doors of large hydropower stations. The door-drop control method performs logical OR operations on the first, second, third, fourth and fifth door-drop control signals to obtain an output signal that acts on the rapid doors of large hydropower stations to complete the door-drop; the first door-drop control signal is a rapid door-drop button signal or a rapid door-drop relay signal or an emergency rapid door-drop button signal of an analog return screen; the second door-drop control signal is a unit shutdown signal for a type of mechanical accident shutdown; the third door-drop control signal is a rapid shutdown process start signal; the fourth door-drop control signal is an emergency shutdown process start signal; the fifth door-drop control signal is a low oil pressure and low oil level signal of the unit speed governor hydraulic system.

[0005] The door drop control method performs a logical OR operation on a rapid door drop button signal, a rapid door drop relay signal, and a simulated return screen emergency rapid door drop button signal to generate a first door drop control signal. The rapid door drop button signal is connected to a first input of a first logical OR module via a first delay gate; the rapid door drop relay signal is connected to a second input of the first logical OR module via a second delay gate; and the simulated return screen emergency rapid door drop button signal is connected to a third input of the first logical OR module via a third delay gate. The first logical OR module outputs the first door drop control signal.

[0006] Preferably, the delay time of the first delay gate is 500-1000ms, the delay time of the second delay gate is 500-1000ms, and the delay time of the third delay gate is 500-1000ms.

[0007] Furthermore, the door-dropping control method performs a logical AND operation on a type of mechanical accident shutdown signal, a negated signal indicating the unit shutdown status, and a negated signal indicating the unit water system operating status, to generate a second door-dropping control signal. The type of mechanical accident shutdown signal is connected to the first input of a first logical AND module; the unit shutdown status signal is connected to the second input of the first logical AND module via a NOT gate; and the unit water system operating status is connected to the third input of the first logical AND module via a NOT gate. The first logical AND module outputs the second door-dropping control signal.

[0008] Furthermore, the door drop control method performs a logical AND operation on the unit rapid shutdown process initiation signal and the rapid shutdown first step timeout alarm signal to obtain a third door drop control signal. The unit rapid shutdown process initiation signal is connected to the first input terminal of a second logical AND module; the rapid shutdown first step timeout alarm signal is connected to the second input terminal of the second logical AND module; and the second logical AND module outputs the third door drop control signal.

[0009] Furthermore, the door drop control method performs a logical AND operation on the unit emergency shutdown process initiation signal and the emergency shutdown second step timeout alarm signal to obtain a fourth door drop control signal. The unit emergency shutdown process initiation signal is connected to the first input terminal of a third logical AND module; the emergency shutdown second step timeout alarm signal is connected to the second input terminal of the third logical AND module; and the third logical AND module outputs the fourth door drop control signal.

[0010] Preferably, the door drop control method performs a logical OR operation on the speed regulator hydraulic system low oil pressure fault signal and the speed regulator hydraulic system low oil level fault signal to obtain a hydraulic system fault signal, and then performs a logical AND operation on the speed regulator hydraulic system fault signal with the unit shutdown status signal not acting, the unit water system operation status signal not acting, the unit actual speed <10% rated speed node signal not acting, the guide vane position no-load below signal not acting, the guide vane fully closed signal not acting, and the speed regulator liquid system door drop soft pressure plate being put into use to obtain the fifth door drop control signal. Among them, the speed regulator hydraulic system low oil pressure fault signal and the speed regulator hydraulic system low oil level fault signal are respectively connected to the first and second input ends of the second logic OR module, and the third logic OR module outputs the hydraulic system fault signal; the hydraulic system fault signal is connected to the first input end of the fourth logic AND module via the fourth delay gate, the unit shutdown status signal is connected to the second input end of the fourth logic AND module via the NOT gate, the unit water system operation status signal is connected to the third input end of the fourth logic AND module via the NOT gate, the unit actual speed <10% rated speed judgment signal is connected to the fourth input end of the fourth logic AND module via the NOT gate, the guide vane position no-load below signal is connected to the fifth input end of the fourth logic AND module via the NOT gate, the guide vane fully closed signal is connected to the sixth input end of the fourth logic AND module via the NOT gate, the speed regulator hydraulic system drop door soft pressure plate input signal is connected to the seventh input end of the fourth logic AND module; the fourth logic AND module outputs the fifth drop door control signal.

[0011] Preferably, the door drop control method performs a logical AND operation on the judgment signal that the pressure of the speed regulator hydraulic system pressure tank is lower than the oil pressure threshold and the normal signal of the pressure tank pressure channel, the pressure tank accident low oil pressure signal, and the hydraulic system pipeline accident low oil pressure signal to obtain a speed regulator hydraulic system low oil pressure fault signal.

[0012] Furthermore, the pressure signal of the speed regulator hydraulic system pressure tank is connected to the first input end of the fifth logic AND module via the first logic comparator, the normal signal of the pressure channel of the speed regulator hydraulic system pressure tank is connected to the second input end of the fifth logic AND module, the accident low oil pressure signal of the speed regulator hydraulic system pressure tank is connected to the third input end of the fifth logic AND module, the accident low oil pressure signal of the hydraulic system pipeline is connected to the fourth input end of the fifth logic AND module, and the fifth logic AND module outputs a low oil pressure fault signal of the speed regulator hydraulic system.

[0013] Preferably, the door drop control method performs a logical AND operation on the judgment signal that the oil level of the pressure tank of the speed regulator hydraulic system is lower than the oil level threshold and the normal signal of the pressure tank oil level channel, the pressure tank accident low oil level signal, and the pressure tank low oil level alarm signal to obtain a low oil level fault signal of the speed regulator hydraulic system.

[0014] Furthermore, the oil level signal of the speed regulator hydraulic system pressure tank is connected to the first input end of the sixth logic AND module via the second logic comparator, the normal signal of the oil level channel of the speed regulator hydraulic system pressure tank is connected to the second input end of the sixth logic AND module, the accident low oil level signal of the speed regulator hydraulic system pressure tank is connected to the third input end of the sixth logic AND module, the low oil level alarm signal of the speed regulator hydraulic system pressure tank is connected to the fourth input end of the sixth logic AND module, and the sixth logic AND module outputs a low oil level fault signal of the speed regulator hydraulic system.

[0015] Preferably, the oil pressure threshold is 5.2 MPa.

[0016] Preferably, the oil level threshold is 1000 mm.

[0017] Compared with the existing technology, the beneficial effect of the present invention is to make full use of program condition judgment and scientific and reasonable control process to execute the rapid door dropping process of large hydropower stations to eliminate the risk of flooding of power plants, eliminate the potential hidden dangers of traditional single signal outlets or signal jitter causing the rapid door to fall by mistake, completely eliminate the risk of single-point false operation outlet, and greatly improve the reliability of the door dropping protection action. The safety and practicality have been greatly improved, and can effectively prevent the occurrence of power plant flooding accidents, major casualties and damage to equipment and facilities. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present invention will be further described below with reference to the accompanying drawings and examples.

[0019] Figure 1 This is a logic diagram of the door-drop control of a large hydropower station rapid door according to an embodiment of the present invention.

[0020] Explanation of the accompanying drawings: first delay gate 1, second delay gate 2, third delay gate 3, first logic OR module 4, first logic AND module 5, second logic AND module 6, third logic AND module 7, first logic comparator 8, fifth logic AND module 9, second logic comparator 10, sixth logic AND module 11, second logic OR module 12, fourth delay gate 13, fourth logic AND module 14, third logic OR module 15. DETAILED DESCRIPTION

[0021] In the embodiment, the large hydro-generator set has states such as shutdown state, water system operation state, startup process, idling state, no-load state, grid-connected state, and shutdown process.

[0022] like Figure 1 As shown, the large hydropower station rapid door drop control method includes:

[0023] 1) When a large hydro-turbine generator set is in operation or standby, the action signal of the fast door button is detected and connected to the pin IN of the first delay gate 1. The first delay signal T1 is connected to the pin PT of the first delay gate 1 and then output; in the embodiment, the value of T1 is 500-1000ms.

[0024] The fast door button of a large hydropower station is arranged on the cabinet door of the LCU water turbine backup panel of the unit. It is a passive button and sends the signal to the process for judgment. The T1 delay can effectively prevent the signal jitter from causing the door drop signal to be erroneously output.

[0025] 2) When the large hydro-generator set is in operation or standby, the action signal of the fast door relay is detected and connected to the pin IN of the second delay gate 2. The second delay signal T2 is connected to the pin PT of the second delay gate 2 and then output; in the embodiment, the value of T2 is 500-1000ms.

[0026] The fast-drop door relay is arranged in the unit's LCU local cabinet PC cabinet. In order to prevent the relay from erroneously outputting, two fast-drop door relays are connected in series and then output, and the signal is sent to the process judgment; the T2 delay can effectively prevent the signal jitter from causing the door drop signal to be erroneously output.

[0027] 3) When a large hydro-turbine generator set is in operation or standby, an action signal of the emergency fast door button of the simulated return screen is detected and connected to the pin IN of the third delay gate 3. The third delay signal T3 is connected to the pin PT of the third delay gate 3 and then output; in the embodiment, the value of T3 is 500-1000ms.

[0028] The emergency fast-drop door button on the simulated return screen of a large hydropower station is arranged on the simulated return screen in the central control room. It is a passive button and the signal is sent to the process for judgment. This is conducive to the operating personnel pressing the emergency fast-drop door button on the simulated return screen as soon as they find equipment abnormalities to deal with equipment abnormalities in an emergency; the T3 delay can effectively prevent signal jitter from causing erroneous output of the door drop signal.

[0029] 4) The shutdown status signal of the large hydro-generator unit is not activated, the water system operation status signal of the unit is not activated, and the first-class mechanical accident shutdown signal are ANDed together and output, wherein the output signal is connected to the input pin IN2 of the third logic OR module 15.

[0030] 5) The large hydro-generator rapid shutdown process start signal and the rapid shutdown first step timeout alarm signal are ANDed together and then output, wherein the output signal is connected to the input pin IN3 of the third logic OR module 15 .

[0031] In this embodiment, the rapid shutdown process for a hydropower unit includes nine steps, executed sequentially. After the rapid shutdown process is initiated, the first step is to activate the governor shutdown solenoid valve command. If the governor guide vanes do not close after this command is issued, or the guide vanes are above no-load, or the unit's active power exceeds a certain value (in this embodiment, this value is 5% of the rated power), the conditions for skipping from the first step to the second step cannot be met. A timeout alarm is triggered when the governor shutdown solenoid valve command is issued. If the conditions for skipping to the second step are not met by the maximum operating time of the first step, a timeout alarm for the first step of the rapid shutdown is issued. The maximum operating time is set to 30 seconds in this embodiment.

[0032] 6) The large hydro-generator emergency shutdown process start signal and the emergency shutdown second step timeout alarm signal are ANDed together and then output, wherein the output signal is connected to the input pin IN4 of the third logic OR module 15 .

[0033] In this embodiment, the emergency shutdown process for a hydropower unit consists of seven steps, executed sequentially. After the emergency shutdown process is initiated, the first step is to decouple the unit, and the second step is to activate the governor shutdown solenoid valve. If the governor guide vanes do not close or are above no-load after this command is issued, the conditions for transitioning from step 2 to step 3 cannot be met. A timeout alarm is triggered from the issuance of the governor shutdown solenoid valve command. If the conditions for transitioning to step 3 are still not met by the time the maximum run time for step 2 is reached, the second step of the emergency shutdown will time out. In this embodiment, the maximum run time is set to 30 seconds.

[0034] 7) The oil tank pressure Pt of the hydraulic system of the large hydro-generator speed governor is connected to the pin IN1 of the first logic comparator 8, and the oil pressure threshold P1 signal is connected to the pin IN2 of the first logic comparator 8. The two are compared and output, where the output signal is connected to the input pin IN1 of the fifth logic AND module 9. In the embodiment, P1 is 5.2 MPa based on the low oil pressure action of the hydraulic system of the large hydro-generator speed governor.

[0035] In the embodiment, the method for determining the oil pressure threshold value P1 includes: repeatedly operating the guide vane three times, with the guide vane opening ranging from 0% to 100%, then from 100% to 0%, and finally from 0% to 100%, recording the low oil pressure action value as P1, and serving as a constant value for program logic judgment.

[0036] In the embodiment, the pressure of the hydraulic oil tank of the speed governor of a large hydro-generator set is collected by a pressure sensor and sent to the monitoring process for judgment in the form of 4-20mA.

[0037] 8) The oil level Lt of the hydraulic system pressure tank of the large hydro-generator speed governor is connected to the pin IN1 of the second logic comparator 10, and the oil level threshold L1 signal is connected to the pin IN2 of the second logic comparator 10. After comparison, the two are output, where the output signal is connected to the input pin IN1 of the sixth logic AND module 11;

[0038] In the embodiment, the oil level threshold L1 is determined according to the low oil level action of the hydraulic system of the large hydro-generator set governor, and the value of L1 is 1000 mm.

[0039] In the embodiment, a method for determining the oil level threshold value L1 includes: using the oil suction port of the governor oil pipe in the pressure oil tank as a reference to effectively prevent air from entering the oil pipe; when the guide vanes are opened from 0% to 100%, the oil level in the pressure oil tank is exactly flush with the oil suction port of the governor oil pipe in the pressure oil tank; and the initial liquid level when the guide vanes are opened from 0% is L1.

[0040] The oil level of the pressure tank of the hydraulic system of the speed governor of a large hydro-turbine generator set is collected by a level gauge and sent to the monitoring process for judgment through 4-20mA. The level gauge adopts a float connecting rod level gauge with a magnetic flap.

[0041] 9) The output signals obtained in steps 1), 2), and 3) are respectively connected to the input pins IN1, IN2, and IN3 of the first logic OR module 4, and then output after performing an OR operation. The output pin Q of the first logic OR module 4 is connected to the input pin IN1 of the third logic OR module 15.

[0042] 10) The normal pressure channel signal of the pressure tank of the large hydro-turbine generator set governor, the accident low oil pressure signal of the pressure tank of the governor hydraulic system, and the accident low oil pressure signal of the pipeline of the governor hydraulic system are respectively connected to the input pins IN2, IN3, and IN4 of the fifth logic AND module 9, and are output after being ANDed with the signal obtained in step 7). The output signal is connected to the input pin IN1 of the second logic OR module 12.

[0043] The low oil pressure signal of the governor hydraulic system pressure tank accident and the low oil pressure signal of the governor hydraulic system pipeline accident are collected respectively through the low oil pressure switch. The low oil pressure switch is a passive node and its setting value is determined in a similar way to the oil pressure threshold P1.

[0044] 11) The normal oil level channel signal of the hydraulic system pressure tank of the large hydro-generator set governor, the accident low oil level signal of the hydraulic system pressure tank, and the low oil level alarm signal of the hydraulic system pressure tank are respectively connected to the input pins IN2, IN3, and IN4 of the sixth logic AND module 11, and are output after being ANDed with the signal obtained in step 8). The output signal is connected to the input pin IN2 of the second logic OR module 12.

[0045] The accidental low oil level signal of the hydraulic system pressure tank of the speed regulator and the low oil level alarm signal of the hydraulic system pressure tank of the speed regulator are respectively collected through the magnetic switch. The magnetic switch is installed on the float connecting rod liquid level gauge and is sent to the passive node. The setting value of the accidental low oil level of the hydraulic system pressure tank of the speed regulator is determined by the above-mentioned L1. The setting value of the low oil level alarm of the hydraulic system pressure tank of the speed regulator is set according to the lowest oil level during the operation of the hydraulic system. In the embodiment, its value is 1600mm.

[0046] 12) The signals obtained in step 10) and step 11) are ORed together and outputted. The output signal of the second logic OR module 12 is connected to the pin IN of the fourth delay gate 13 .

[0047] 13) The fourth delay signal T4 is connected to the pin PT of the fourth delay gate 13 and is output after the condition in step 12) is met, wherein the output signal is connected to the input IN1 of the fourth logic AND module 14; in the embodiment, the value of T4 is 30-40s.

[0048] 14) The shutdown status signal of the large hydro-turbine generator unit is not activated, the unit water system operation status signal is not activated, the unit speed <10% rated speed node signal is not activated, the guide vane position no-load or lower signal is not activated, and the guide vane fully closed signal is not activated. The above signals are respectively connected to the input pins IN2, IN3, IN4, IN5, and IN6 of the fourth logic AND module 14, and are also ANDed with the governor fluid system drop door soft pressure plate input signal and the hydraulic system fault signal obtained in step 13) and then output. The above governor fluid system drop door soft pressure plate is the soft pressure plate in the rapid door drop door process control of the large hydropower station. The soft pressure plate input signal is connected to the input pin IN5 of the third logic OR module 15.

[0049] The node signal of unit speed <10% rated speed is the 10% speed node signal sent by the speed device of the speed governor. The signal below the guide vane position no-load is sent through the magnetic switch or micro travel switch as the basis for process judgment. The magnetic switch or micro travel switch is installed on the travel rod of the guide vane relay in the waterwheel room.

[0050] 15) The signals obtained in step 4), step 5), step 6), step 9) and step 14) are output after being ORed. The first output is the remote emergency closing signal of the water inlet rapid door 1, the second output is the remote emergency closing signal of the water inlet rapid door 2, and the third output is the remote emergency closing signal of the water inlet rapid door of the simulated return screen. It is used for the rapid door closing of large hydropower stations.

Claims

1. A method for controlling the rapid door drop of a large hydropower station, characterized in that: The door drop control method performs a logical OR operation on the first, second, third, fourth and fifth door drop control signals to obtain an output signal for the rapid door of a large hydropower station to complete the door drop; The first door closing control signal is the fast door closing button signal or the fast door closing relay signal or the analog return screen emergency fast door closing button signal; The second door drop control signal is a unit shutdown signal for a type 1 mechanical accident shutdown; The third door drop control signal is the rapid shutdown process start signal; The fourth door drop control signal is the emergency shutdown process start signal; The fifth door drop control signal is the low oil pressure and low oil level signal of the unit speed governor hydraulic system; The door drop control method performs a logical AND operation on a type of mechanical accident shutdown signal, a negated signal of the unit shutdown state, and a negated signal of the unit water system operation state to obtain a second door drop control signal; One type of mechanical accident shutdown signal is connected to the first input end of the first logic AND module; the unit shutdown status signal is connected to the second input end of the first logic AND module via a NOT gate; the unit water system operation status is connected to the third input end of the first logic AND module via a NOT gate; the first logic AND module outputs a second door drop control signal.

2. The large hydropower station rapid door drop control method according to claim 1, characterized in that: The door drop control method performs a logic OR operation on the fast door drop button signal, the fast door drop relay signal and the simulated return screen emergency fast door drop button signal to obtain a first door drop control signal; The fast door button signal is connected to the first input terminal of the first logic or module through the first delay gate; The fast door closing relay signal is connected to the second input terminal of the first logic or module through the second delay gate; The simulated return screen emergency drop fast door button signal is connected to the third input terminal of the first logic or module through the third delay gate; The first logic or module outputs a first door-drop control signal.

3. The large hydropower station rapid door drop control method according to claim 1, characterized in that: The door drop control method performs a logical AND operation on the unit rapid shutdown process start signal and the rapid shutdown first step timeout alarm signal to obtain a third door drop control signal; The unit rapid shutdown process start signal is connected to the first input terminal of the second logic AND module; The timeout alarm signal of the first step of the rapid shutdown is connected to the second input terminal of the second logic AND module; The second logic AND module outputs a third door-drop control signal.

4. The large hydropower station rapid door drop control method according to claim 1, characterized in that: The door drop control method performs a logical AND operation on the unit emergency shutdown process start signal and the emergency shutdown second step timeout alarm signal to obtain a fourth door drop control signal; The unit emergency shutdown process start signal is connected to the first input terminal of the third logic AND module; The emergency shutdown second step timeout alarm signal is connected to the second input terminal of the third logic AND module; The third logic AND module outputs a fourth door-drop control signal.

5. The large hydropower station rapid door drop control method according to claim 1, characterized in that: The door drop control method performs a logical OR operation on the governor hydraulic system low oil pressure fault signal and the governor hydraulic system low oil level fault signal to obtain a hydraulic system fault signal, and then performs a logical AND operation on the governor hydraulic system fault signal with the unit shutdown state signal not being acted, the unit water system operation state signal not being acted, the unit actual speed <10% rated speed node signal not being acted, the guide vane position below no-load signal not being acted, the guide vane fully closed signal not being acted, and the governor hydraulic system door drop soft pressure plate being put into action to obtain a fifth door drop control signal; Wherein, the governor hydraulic system low oil pressure fault signal and the governor hydraulic system low oil level fault signal are connected to the first and second input terminals of the second logic or module respectively, and the third logic or module outputs the hydraulic system fault signal; The hydraulic system fault signal is connected to the first input terminal of the fourth logic AND module via the fourth delay gate, the unit shutdown status signal is connected to the second input terminal of the fourth logic AND module via the NOT gate, the unit water system operation status signal is connected to the third input terminal of the fourth logic AND module via the NOT gate, the unit actual speed <10% rated speed judgment signal is connected to the fourth input terminal of the fourth logic AND module via the NOT gate, the guide vane position below no-load signal is connected to the fifth input terminal of the fourth logic AND module via the NOT gate, the guide vane fully closed signal is connected to the sixth input terminal of the fourth logic AND module via the NOT gate, the governor hydraulic system drop door soft pressure plate input signal is connected to the seventh input terminal of the fourth logic AND module; the fourth logic AND module outputs the fifth drop door control signal.

6. The large hydropower station rapid door drop control method according to claim 5, characterized in that: The door drop control method performs a logical AND operation on a judgment signal indicating that the pressure of the governor hydraulic system pressure tank is lower than the oil pressure threshold, a normal pressure channel signal of the pressure tank, a low oil pressure signal caused by an accident in the pressure tank, and a low oil pressure signal caused by an accident in the hydraulic system pipeline, to obtain a low oil pressure fault signal of the governor hydraulic system; The pressure signal of the pressure tank of the speed regulator hydraulic system is connected to the first input terminal of the fifth logic AND module via the first logic comparator. The normal signal of the pressure channel of the speed regulator hydraulic system pressure tank is connected to the second input end of the fifth logic AND module, the accident low oil pressure signal of the speed regulator hydraulic system pressure tank is connected to the third input end of the fifth logic AND module, the accident low oil pressure signal of the hydraulic system pipeline is connected to the fourth input end of the fifth logic AND module, and the fifth logic AND module outputs the speed regulator hydraulic system low oil pressure fault signal.

7. The large hydropower station rapid door drop control method according to claim 5, characterized in that: The door drop control method performs a logical AND operation on the judgment signal that the oil level of the pressure tank of the speed governor hydraulic system is lower than the oil level threshold, the normal signal of the pressure tank oil level channel, the pressure tank accident low oil level signal, and the pressure tank low oil level alarm signal to obtain a speed governor hydraulic system low oil level fault signal; The oil level signal of the speed regulator hydraulic system pressure tank is connected to the first input end of the sixth logic AND module via the second logic comparator, the normal signal of the oil level channel of the speed regulator hydraulic system pressure tank is connected to the second input end of the sixth logic AND module, the accident low oil level signal of the speed regulator hydraulic system pressure tank is connected to the third input end of the sixth logic AND module, the low oil level alarm signal of the speed regulator hydraulic system pressure tank is connected to the fourth input end of the sixth logic AND module, and the sixth logic AND module outputs a low oil level fault signal of the speed regulator hydraulic system.

8. The large hydropower station rapid door drop control method according to claim 6, characterized in that: The oil pressure threshold is 5.2 MPa.

9. The large hydropower station rapid door drop control method according to claim 7, characterized in that: The oil level threshold is 1000 mm.

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