Water-turbine generator set top cover drainage system

Abstract

The utility model discloses a water-turbine generator set top cover drainage system. A traditional top cover drainage system can cause frequent starting and stopping of a water pump, and frequent starting and stopping impact accelerates damage to elements or equipment such as a contactor, a relay, a motor and a pump body of the top cover drainage system. The device comprises a primary power supply loop, a secondary control loop and a water turbine inner top cover, a liquid level sensor is installed at the bottom of the water turbine inner top cover, the input end of a circuit breaker is connected with three-phase mains supply, and the output end of the circuit breaker is electrically connected with the power input end of a frequency converter. The power output end of the frequency converter is electrically connected with the power input ends of the variable frequency motor and the pump set; the input end of the air switch is connected to one phase of the three-phase mains supply in parallel, the coil output of the first relay is connected to the N pole of the three-phase mains supply, and the normally open contact of the second relay is connected to the two ends of the normally open contact of the first relay in parallel. The drainage device is used for drainage of the top cover of the water-turbine generator set.

Description

Technical Field

[0001] The utility model relates to a water turbine generator set top cover drainage system. Background Art

[0002] When the turbine unit is rotating, in order to prevent the dry friction between the stationary main shaft seal part and the rotating slip ring part from damaging the main shaft seal, the main shaft seal ring is usually lifted up by the main shaft seal water pressure to form a water film between the seal ring and the slip ring. However, this will also cause a gap between the seal ring and the slip ring, and some main shaft seal water or water in the volute will leak into the inner top cover through the gap. In order to prevent the water level in the inner top cover from being too high, a top cover drainage system is usually set up. When the water level in the inner top cover reaches the pump start level, the top cover drainage pump is started to drain water until the water level in the inner top cover reaches the pump stop level, and then the top cover drainage pump is stopped.

[0003] Because the amount of water leakage from the top cover of the turbine is different when the unit is operating under different operating conditions, and the amount of water leakage may suddenly increase with the wear of the seal, the drainage volume calculation is complicated, and it is impossible to select a fixed-discharge power frequency drainage pump set in a targeted manner. The traditional top cover drainage system will cause the water pump to start and stop more frequently. The frequent start and stop impacts accelerate the damage of components or equipment such as contactors, relays, motors and pump bodies of the top cover drainage system, which can easily lead to water flooding and "burning" of water guide bearing bearings, and even cause "non-stop" accidents of the unit, threatening the safe operation of the turbine generator set. Utility Model Content

[0004] The utility model aims to solve the above-mentioned technical problems and provide a water turbine generator set top cover drainage system.

[0005] The above purpose is achieved through the following technical solutions:

[0006] A water turbine generator set top cover drainage system, comprising a primary power supply circuit, a secondary control circuit and a turbine inner top cover, wherein a liquid level sensor is installed at the bottom of the turbine inner top cover, wherein the primary power supply circuit comprises a programmable logic controller, a circuit breaker, a frequency converter, a variable frequency motor and a pump group, wherein the input end of the circuit breaker is connected to a three-phase mains power supply, and the output end is electrically connected to a power input end of the frequency converter, and the power output end of the frequency converter is electrically connected to a power input end of the variable frequency motor and a pump group;

[0007] The secondary control circuit includes an air switch, a normally closed contact of a third relay, a normally open contact of a first relay, a fault normally closed contact of the frequency converter and a coil of the first relay connected in series in sequence. The input end of the air switch is connected in parallel to one phase of the three-phase mains power, the coil output of the first relay is connected to the N pole of the three-phase mains power, and the normally open contact of the second relay is connected in parallel to both ends of the normally open contact of the first relay.

[0008] The described water turbine generator set top cover drainage system, the described programmable logic controller comprises an analog quantity input module, a discrete quantity output module, an analog quantity output module and a discrete quantity input module.

[0009] In the water turbine generator set top cover drainage system, the coil of the second relay and the coil of the third relay are respectively connected to the discrete quantity output module.

[0010] In the water turbine generator set top cover drainage system, the liquid level sensor is connected to the analog input module.

[0011] In the water turbine generator set top cover drainage system, the analog output module is connected to the frequency signal input contact of the frequency converter.

[0012] In the water turbine generator set top cover drainage system, the circuit breaker is a circuit breaker with an overload protection function.

[0013] In the water turbine generator set top cover drainage system, the first relay is a 220V AC relay.

[0014] In the water turbine generator set top cover drainage system, the second relay and the third relay are 24V DC relays. Beneficial Effects

[0015] 1. The utility model can adjust the frequency of the inverter by the rising rate of the water level on the top cover, thereby changing the drainage volume of the drainage pump group. The water level on the top cover can be maintained within a safe value range under any operating condition of the unit, and the system will continue to operate stably during the operation of the unit. Frequent start and stop impacts will not accelerate the damage of system components or equipment such as contactors, relays, motors and pump bodies of the top cover drainage system, and the frequency output of the inverter is maintained within a reasonable range.

[0016] 2. After the utility model is remotely started, the discrete output module will drive the coil of the second relay to close the normally open contact of the second relay, and at the same time set the stop coil DO_K2 of the inverter to 0 to form a lock to prevent the logical conflict of the inverter starting and stopping at the same time.

[0017] 3. The fault normally closed contact of the inverter of the utility model is connected to the secondary control circuit. When the inverter body fails during operation, the fault normally closed contact of the inverter opens. At this time, the control circuit is disconnected, the inverter stops running, and the operation duty personnel can be notified in time. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Attached Figure 1 It is the principle diagram of the utility model;

[0019] Attached Figure 2This is a schematic diagram of control signal connection;

[0020] In the figure: 1. Programmable logic controller; 2. Inner cover of turbine; 3. Liquid level sensor; 4. Frequency converter; 5. Frequency converter motor and pump group; 6. Circuit breaker; 7. Air switch; 8. First relay; 9. Second relay; 10. Third relay; 111. Analog input module; 112. Analog output module; 113. Discrete output module; 114. Discrete input module. DETAILED DESCRIPTION

[0021] Reference Figure 1-Figure 2 , a water turbine generator set top cover drainage system, including a primary power supply circuit, a secondary control circuit and a turbine inner top cover 2, wherein a liquid level sensor 3 is installed at the bottom of the turbine inner top cover;

[0022] Pins 1, 3, and 5 of the circuit breaker 6 are respectively connected to A, B, and C of the 400V mains, and pins 2, 4, and 6 are respectively connected to the power input pins R, S, and T of the inverter 4; the power output pins U, V, and W of the inverter 4 are respectively connected to the power input pins U1, V1, and W1 of the variable frequency motor and pump group 5, and the start control pins FWD and CM_1 are respectively connected to the normally open contact pins 22 and 24 of the first relay 8, the inverter 4 body fault signal output pins 30A and 30C are normally closed contacts, the inverter 4 operation signal output pins Y1 and Y1E are normally open contacts, and the inverter 4 pins 1L_2 and C1 are Frequency signal input contact; Pin 1 of the air switch 7 is connected in parallel to the C phase of the 400V mains, and Pin 2 is connected in series to the normally closed contact pin 12 of the third relay 10; the normally open contact pin 14 of the first relay 8 and the normally open contact pin 14 of the second relay 9 are connected in parallel to the normally closed contact pin 11 of the third relay 10, and the normally open contact pin 11 of the first relay 8 and the normally open contact pin 11 of the second relay 9 are connected in parallel to the fault pin 30A of the inverter 4; the coil pin A1 of the first relay 8 is connected in series to the fault pin 30C of the inverter 4, and the coil pin A2 is connected to the system N pole;

[0023] The programmable logic controller includes an analog quantity input module 111, a discrete quantity output module 113, an analog quantity output module 112 and a discrete quantity input module 114;

[0024] The remote start top cover drainage system signal, the remote stop top cover drainage system signal, and the inverter 4 operation signal are respectively connected to the discrete quantity input module 114 channels 1, 2, and 3, the second relay 9 and the third relay 10 are respectively connected to the discrete quantity output module 113 channels 1 and 2, the liquid level sensor 3 is connected to the analog quantity input module 111 channel 1, and the analog quantity output module 112 channel 1 is connected to the frequency signal input contact of the inverter 4;

[0025] The circuit breaker is a circuit breaker with an overload protection function, the first relay is a 220V AC relay, and the second relay and the third relay are 24V DC relays.

[0026] Set the inverter 4 to the remote control mode, close the system main circuit breaker 6 and the control circuit air switch 7, and then the main power supply of the inverter 4 is turned on. Since the start control pins FWD and CM_1 of the inverter 4 do not form a closed circuit, the inverter 4 is in the working preparation state. Under normal conditions, the inverter 4 body fault signal output pins 30A and 30C are closed, and the inverter 4 operation signal output pins Y1 and Y1E are open.

[0027] Start the programmable logic controller, the analog input module 111 converts the collected real-time value of the inner top cover water level into a digital signal and stores it in the variable inner top cover water level real-time value AI_LT, the discrete input module 114 stores the collected pulse start signal in the variable remote start top cover drainage system signal DI_START, the pulse stop signal in the variable remote stop top cover drainage system signal DI_STOP, and the inverter operation signal in the variable inverter operation signal DI_RUN.

[0028] When the system is remotely started, the control system receives the signal of remotely starting the top cover drainage system. At this time, the discrete output module 113 will drive the coil of the second relay 9 to close the normally open contacts 11 and 14 of the second relay 9, and at the same time set the inverter stop coil DO_K2 to 0 to form a lock to prevent the logical conflict of the inverter starting and stopping at the same time. At this time, the control loop is closed, the coil of the first relay 8 is energized, so that the normally open contacts 11 and 14 of the first relay 8 are closed to form a self-maintaining closed state of the control loop, and the normally open contacts 22 and 24 of the first relay 8 are closed, so that the start control pins FWD and CM_1 of the inverter 4 form a closed loop, and the analog output module 112 converts the 40Hz frequency into an analog signal and outputs it to the inverter 4. The inverter 4 starts to run at the initial frequency of 40Hz, driving the variable frequency motor and pump group 5 to run drainage.

[0029] Before the control system receives a remote signal to stop the top cover drainage system, due to the self-holding circuit state of the first relay 8, the control circuit is always closed, and the variable frequency motor and pump group 5 continue to run to drain water.

[0030] When the remote stop system is in progress, the control system receives the remote start top cover drainage system signal DI_STOP as 1, at this time, the discrete output module 113 will drive the coil of the third relay 10 to disconnect the normally closed contacts 11 and 12 of the third relay 10, and at the same time, the inverter start coil DO_K1 is set to 0 to form a lock to prevent the logical conflict of the inverter start and stop being executed at the same time. At this time, the control loop is disconnected, the coil of the first relay 8 loses power, so that the normally open contacts 11, 14 and the normally open contacts 22, 24 of the first relay 8 are restored to the open state, the start control pins FWD and CM_1 of the inverter 4 are open, the inverter 4 stops running, and the variable frequency motor and pump group 5 stop.

[0031] When the inverter 4 body fails during operation, the inverter 4 body fault signal output pins 30A and 30C are open, at which time the control circuit is disconnected, the inverter 4 stops running and the operation signal output pins Y1 and Y1E contacts are open, and the operation duty personnel are notified in time. The control process is similar to the remote stop system and will not be repeated;

[0032] When the inverter 4 is overloaded, the circuit breaker 6 trips, the inverter 4 loses power and stops running, and the contacts of the operation signal output pins Y1 and Y1E are open, which can promptly notify the operation duty personnel to protect the inverter 4.

Claims

1. A water turbine generator set top cover drainage system, comprising a primary power supply circuit, a secondary control circuit and a turbine inner top cover, wherein a liquid level sensor is installed at the bottom of the turbine inner top cover, and is characterized in that: The primary power supply circuit includes a programmable logic controller, a circuit breaker, a frequency converter, a variable frequency motor and a pump group. The input end of the circuit breaker is connected to the three-phase mains power, and the output end is electrically connected to the power input end of the frequency converter. The power output end of the frequency converter is electrically connected to the power input end of the variable frequency motor and the pump group. The secondary control circuit includes an air switch, a normally closed contact of a third relay, a normally open contact of a first relay, a fault normally closed contact of the frequency converter and a coil of the first relay connected in series in sequence. The input end of the air switch is connected in parallel to one phase of the three-phase mains power, the coil output of the first relay is connected to the N pole of the three-phase mains power, and the normally open contact of the second relay is connected in parallel to both ends of the normally open contact of the first relay.

2. A water turbine generator set top cover drainage system according to claim 1, characterized in that: The programmable logic controller comprises an analog quantity input module, a discrete quantity output module, an analog quantity output module and a discrete quantity input module.

3. A water turbine generator set top cover drainage system according to claim 1, characterized in that: The coil of the second relay and the coil of the third relay are respectively connected to the discrete quantity output module.

4. A water turbine generator set top cover drainage system according to claim 2, characterized in that: The liquid level sensor is connected to the analog input module.

5. A water turbine generator set top cover drainage system according to claim 2, characterized in that: The analog output module is connected to the frequency signal input contact of the frequency converter.

6. A water turbine generator set top cover drainage system according to claim 1, characterized in that: The circuit breaker is a circuit breaker with an overload protection function.

7. A water turbine generator set top cover drainage system according to claim 1, characterized in that: The first relay is a 220V AC relay.

8. The water turbine generator set top cover drainage system according to claim 1, characterized in that: The second relay and the third relay are 24V DC relays.

Images